Hand-Miller Review Flashcards
Anatomy of the extensor Mechanism
Extensor retinaculum: Prevents extensor tendon bowstringing at wrist
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Juncturae tendinum: Extensor tendon interconnections in hand that may mask proximal tendon lacerations
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Sagittal bands: Centralize the extensor mechanism and attach to the volar plate at the metacarpophalangeal (MCP) joint
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Central slip: Terminal extensor digitorum communis tendon; inserts at the base of middle phalanx (P2) and aids in proximal interphalangeal (PIP) joint extension
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Lateral bands: Common extensor and intrinsics converge to form terminal extensor tendon, which inserts on base of distal phalanx (P3) and extends distal interphalangeal (DIP) joint.
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Transverse retinacular ligament: Prevents dorsal subluxation of lateral bands in PIP extension, while pulling lateral bands volarly in PIP flexion. Injury may result in swan neck deformity.
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Triangular ligament: Prevents volar subluxation of lateral bands. Injury may result in boutonnière deformity.
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Oblique retinacular ligament (ligament of Landsmeer): Helps link PIP and DIP joint extension
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In PIP flexion is relaxed to allow DIP flexion
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In PIP extension is tight to allow DIP extension
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Grayson/Cleland ligaments: Fibrous skin and neurovascular stabilizers lying volar (Grayson) and dorsal (Cleland) to digital neurovascular bundles, respectively (mnemonic: Grayson is ground; Cleland is ceiling)
Review the extensor compartments of the wrist
Flexor tendon anatomy
Flexor Pulley Anatomy
Flexor digitorum profundus (FDP): Inserts at metadiaphyseal region of the distal phalanx (P3), flexes DIP joint, aids in PIP and MCP flexion
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FDP tendons of the middle, ring, and small fingers have a common muscle belly in the forearm.
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Index FDP often has a distinct muscle belly.
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Flexor digitorum superficialis (FDS): Inserts at metadiaphyseal of the middle phalanx (P2), flexes the PIP joint, aids in MCP flexion
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Small finger FDS: absent approximately 20% of the time
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Campers chiasm: FDS splits at level of proximal phalanx (P1) to allow FDP to pass through it.
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Flexor tendon sheath: Tunnel encompasses tendons distal to MCP joint, creating a closed system separate from surrounding structures.
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Vascular supply: Both intrinsic (direct feeding vessels) and extrinsic (diffusion via synovial sheath to flexor tendons)
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Pulleys: Each digital flexor tendon sheath has five annular pulleys (A1–A5) and three cruciate pulleys (C1–C3)
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A2 and A4 pulleys critical to preventing flexor tendon bowstringing
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A1 involved in trigger finger
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Thumb: 2 or 3 annular pulleys (A1, A2, Av [annular variable]) and an oblique pulley in between that prevents bowstringing of flexor pollicis longus (FPL) tendon,
Contents of the Carpal Tunnel
Contains the median nerve and nine flexor tendons (FPL, four FDS, and four FDP tendons)
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FPL tendon most radial structure in carpal tunnel
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Long and ring FDS tendons are volar to index and small FDS.
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Transverse carpal ligament (TCL): Roof of carpal tunnel
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Ulnar tunnel (Guyon canal): Contains ulnar nerve and artery
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Borders: Volar carpal ligament (roof) and TCL (floor)
Lumbrical Anatomy
The lumbrical muscles flex the metacarpophalangeal joint and extend the proximal interphalangeal joint.
Lumbrical muscles: Originate on radial aspect of FDP tendons, and pass volar to transverse metacarpal ligaments (TMLs) to insert on the radial lateral bands (extensor hood)
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Function: IP joint extension, relaxation of extrinsic flexor system
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Innervation: Radial two lumbricals (median n.), ulnar two lumbricals (ulnar n.)
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Intrinsic tightness: Limited PIP flexion with MCP joints held in extension (intrinsics on stretch, extrinsics [extensor tendons] relaxed)
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Extrinsic tightness: Limited PIP flexion with MCP joints held in flexion (extrinsics on stretch, intrinsics relaxed)
Sensory Patterns of the Hand
Nerve/muscle interactions in the hand
Median nerve: Innervates pronator teres, FDS, FCR, PL, radial two lumbricals (Fig. 7.8)
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Anterior interosseous branch of median nerve (AIN): Innervates FPL, index and long FDPs (50% of the time), pronator quadratus
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Palmar cutaneous branch of median nerve: Usually lies between PL and FCR at distal wrist flexion crease and can be injured during the modified FCR Henry approach in treating distal radius fractures
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Recurrent motor branch of median nerve: Innervates abductor pollicis brevis (APB), opponens pollicis, and superficial head of flexor pollicis brevis (FPB)
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Ulnar nerve: Innervates FCU, ring/small FDPs, long FDP (50% of the time), and ulnar two lumbricals (see Fig. 7.8)
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Deep motor branch of ulnar nerve: Innervates dorsal and volar interossei, abductor digiti minimi (ADM), flexor digitorum minimi, palmaris brevis, and deep head of FPB
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Martin-Gruber anastomoses: Interconnections between motor fibers of the median and ulnar nerves in the forearm
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Incidence: 17% of people
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Type 1 (most common of four variations): Motor branches from the median nerve to the ulnar nerve that innervate median intrinsic muscles is most common.
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Riche-Cannieu anastomoses: Interconnections of motor fibers of the median and ulnar nerve within the palm
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Radial nerve proper: Innervates lateral portion of brachialis (also musculocutaneous), triceps, anconeus, brachioradialis, and extensor carpi radialis longus (ECRL) (see Fig. 7.8)
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Divisions: Superficial sensory branch (SBRN) and posterior interosseous nerve (PIN)
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PIN: Innervates all remaining extensor muscles
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Extensor carpi radialis brevis (ECRB): Variable innervation from either radial nerve proper or PIN
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Terminal branch of PIN: Lies on the floor of fourth extensor compartment and is excised as part of a partial denervation procedure for wrist arthritis
Distal Radius Fracture Overview
Composite figure outlining various important pathologies in the wrist (described in clockwise order from top right [purple] box). • The distal radius fractures often follow specific fracture types involving the radial, ulnar, volar, and dorsal columns. There are a variety of surgical techniques to fix these fractures according to the fracture pattern. • The multiple types of carpal instability include carpal instability nondissociative (CIND), carpal instability dissociative (CID), and carpal instability complex (CIC). CID is one of the more commonly faced pathologies, including dorsal intercalated segment instability (DISI) involving the scapholunate (SL) ligament and extrinsic stabilizers, as well as volar intercalated instability (VISI) involving the lunotriquetral (LT) ligament and extrinsic stabilizers. SL pathology can progress to DISI and eventually to different stages of scapholunate advanced collapse (SLAC) arthritis. • The distal radioulnar joint (DRUJ) has multiple dynamic and static stabilizers. When it is injured, the ulna is able to translate (usually dorsally) with respect to the radius. DRUJ arthritis can happen as a result of trauma (e.g., prior associated fracture), recurrent instability, or either OA or inflammatory arthritis. • The triangular fibrocartilage complex (TFCC) is one of the most important DRUJ stabilizers. Multiple tear patterns may be seen; the Palmer classification being one of the most useful to describe them. A TFCC tear has the potential to destabilize the DRUJ. • There are three types of lunate morphology and two types of capitate morphology. These are important considerations in assessment and treatment of various carpal pathologies. For example, a type 1 (flat) capitate has been shown to be a better indication for proximal row carpectomy than a type 2 (round) or type 3 (V-shaped).
Distal Radius Acceptable Radiographic measurements
Radial height, volar tilt, and radial inclination: 11:12:22 rule
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Radial height: Average 11 mm; less than 5 mm of shortening accepted
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Radial inclination: Average 22 degrees (Fig. 7.10); less than 5-degree change accepted
Distal Radius Fracture Review
Most common fractures of the upper extremity (>300,000 per year) in the United States, with bimodal distribution
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Young patients: High-energy trauma (e.g., motor vehicle accident, fall from height)
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Elderly patients: Low-energy falls; most common upper extremity osteoporotic fracture
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Anatomy
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Distal radius articular surface: Biconcave, scaphoid, and lunate facets
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Distal radioulnar joint (DRUJ): Articulation with ulna at sigmoid notch
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Lister tubercle: Small dorsal prominence; landmark for dorsal approach to wrist; cause of attritional rupture of extensor pollicis longus (EPL) after a distal radius fracture
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Metaphysis: Thin cortex, vulnerable to bending forces
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Deforming force: Brachioradialis insertion on radial styloid
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Normal wrist: Distal radius bears 80% of axial load
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Clinical evaluation
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Pain, swelling, and deformity at the wrist after trauma
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Open injuries more common in young patients
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Arm should be examined for concurrent anatomic snuffbox and ulnar-sided wrist tenderness.
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Median and ulnar nerve function should be assessed.
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Radiographic evaluation (posteroanterior, lateral, and oblique views)
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Intra articular involvement (Fig. 7.9): Fracture pattern, gap, and step-off
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Distal fragment angulation: Apex dorsal (Smith fracture), apex volar (Colles fracture)
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Radial height, volar tilt, and radial inclination: 11:12:22 rule
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Radial height: Average 11 mm; less than 5 mm of shortening accepted
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Radial inclination: Average 22 degrees (Fig. 7.10); less than 5-degree change accepted
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Volar tilt (lunate fossa inclination): Average 11 degrees; less than 10-degree dorsal angulation accepted
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Additional considerations
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Ulnar variance: Neutral (normal), positive, or negative; assessed with forearm in neutral rotation, and compared with contralateral side (Fig. 7.11)
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DRUJ involvement: True lateral radiograph assessed for DRUJ alignment
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Ligamentous injuries: scapholunate (SL), lunotriquetral (LT), or TFCC
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Associated fractures: ulnar styloid, distal ulna, carpus
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Chauffeur fracture: Isolated fracture of radial styloid that may be associated with SL ligament disruption
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Radiocarpal dislocation or “inferior arc” injury: Purely ligamentous or associated with styloid fracture (radial and/or ulnar)
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Highly unstable and difficult to reduce closed
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Other imaging studies: CT for detail of complex intraarticular patterns; MRI for occult fracture, bone contusion, associated soft tissue injury
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Classification
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Common eponyms (Colles, Smith, Barton, Hutchinson) predate radiography
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More than 10 other schemes exist (e.g., AO, Frykman, Fernandez, Melone, Mayo) but largely fail to help with prediction of treatment or prognosis.
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Treatment
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Goals: Maintain reduction until union, restore function, prevent symptomatic posttraumatic radiocarpal osteoarthrosis
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Factors: Age, medical condition, activity demands, bone quality, fracture stability, associated injuries
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Nonoperative: Immobilization ± closed reduction
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Indications for immobilization: Extraarticular, minimally displaced fracture; functionally low-demand patient
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Closed reduction indicated in displaced fracture with abnormal radiographic parameters, especially in functionally high-demand patient
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Technique of closed reduction: Volar translation of lunate with traction and ulnar deviation.
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Dorsal hematoma block with local anesthetic, finger traps
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Re-creation of deformity, manipulation of distal fragment
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Sugar-tong plaster splint with three-point mold
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Aim: To hook volar cortex to try to prevent loss of reduction.
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MCP and IP joints must be kept free for motion.
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Loss of reduction correlates with increasing age.
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Postreduction benchmarks (American Academy of Orthopaedic Surgeons guideline)
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Radial shortening less than 5 mm
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Dorsal articular tilt less than 5–10 degrees
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Intraarticular step-off less than 2 mm
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Immobilization for 6–8 weeks (no evidence to support any particular type)
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Wrist and digit stiffness, muscle atrophy, and disuse osteopenia may result from prolonged immobilization.
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Operative treatment
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Closed reduction and percutaneous pinning (CRPP) (see Fig. 7.9)
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Indications: Extraarticular fracture in younger patients without osteoporosis
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Is less often used today with the advent of volar plating. Can be used as an isolated treatment or as an adjunct with external fixation.
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Techniques: Kapandji intrafocal technique or arthroscopically assisted reduction
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External fixation
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Indications: Alone for unstable fractures with soft tissue compromise or in combination with percutaneous pin fixation or internal fixation techniques in highly unstable fractures
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Articular alignment is difficult to restore.
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Overdistraction may lead to increased risk of complex regional pain syndrome (CRPS).
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Open reduction with internal fixation (ORIF)
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Patients undergoing ORIF should be monitored for symptomatic hardware that may need to be removed to prevent tendon rupture.
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Distraction or bridge plating
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Indications: Alternative to external fixation in highly comminuted unstable fractures or elderly patients with severe osteoporosis. Allows weight bearing through injured extremity and so a consideration in a multiple-trauma patient.
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Technique: Secured second or third metacarpal and radial shaft (Fig. 7.12)
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Can be combined with volar plating
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Disadvantage: Second procedure to remove plate at 8–12 weeks
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Dorsal plating
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Indications: Dorsally displaced fractures with dorsal bony defects
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Technique: Approach between third and fourth extensor compartments
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Enables direct visualization of articular reduction
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Historical disadvantage: Extensor tendon irritation or rupture from prominent hardware
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Volar plating
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Indications (most common): volarly or dorsally displaced fractures, more than 2 mm articular displacement, metaphyseal comminution, combined distal radius and ulna fractures
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Technique: Henry approach between FCR and radial artery or through floor of FCR tendon sheath
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Articular reduction not directly visualized; relies on fluoroscopic guidance
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Fixed-angle and variable-angle plates available
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Plates placed at or proximal to watershed line (Fig. 7.13)
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Repair of pronator quadratus: No clinical benefit
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Can be combined with dorsal bone grafting for dorsal comminution
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Flexor tendon most commonly injured with a plate placed distal to the watershed line is the FPL, followed by the FDP of the index finger.
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Extensor tendon most commonly injured with a volar plate is the EPL, from use of a screw that is too long.
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Fragment-specific techniques
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Considerations: Low-profile constructs, technically challenging
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Indications: May be best suited to certain intraarticular fracture patterns, including those with volar-ulnar (“critical corner”) fragment
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Hook plate may capture volar-ulnar fragment with less chance of flexor tendon irritation than standard volar plate implant.
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Intramedullary nailing
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May have role in stable extraarticular patterns, but minimal data available
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Arthroscopic reduction assistance
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Aids in articular reduction
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Ensures screws do not penetrate the radiocarpal joint
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Additional technical considerations
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Injectable bone substitutes: Calcium phosphate, coralline hydroxyapatite
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Possible role in dorsal or metaphyseal comminution
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Postoperative motion: Evidence does not support any advantage of early over later motion recovery after surgical fixation of distal radius.
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Ulnar styloid fracture: Concurrent treatment of ulnar styloid fracture is not routinely necessary; it has no additional clinical benefit if the DRUJ is stable to clinical examination after the distal radius fracture has been stabilized.
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Painful nonunion/DRUJ instability in small number of cases after radial fracture reduction (<10%)
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Complications
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Acute carpal tunnel syndrome: Characterized by progressive, evolving paresthesias and disproportionate pain; requires emergent median nerve decompression (carpal tunnel release)
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Mild, vague, and nonprogressive sensory dysfunction is not indicative of acute carpal tunnel syndrome.
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Ulnar nerve palsy: Possible after high-energy displaced distal radius fracture
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EPL tendon rupture
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Late complication due to sheath hematoma, attritional wear, and/or vascular insufficiency near the Lister tubercle
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Presentation: Painless, acute loss of thumb extension; inability to lift thumb off table with palm
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Treatment: Extensor indicis proprius (EIP)—EPL tendon transfer followed by PL intercalary autograft reconstruction. The EIP is the more ulnar of the two extensor tendons over the index finger MCP joint and has the most distal muscle belly of the fourth extensor compartment tendons at the wrist.
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Nonunion: Uncommon complication
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Asymptomatic malunion in a functionally low-demand patient does not require treatment
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Ulnocarpal impaction: Can be treated with distal ulna resection (low-demand patient) or ulnar shortening osteotomy (high-demand patient).
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Corrective radius osteotomy with ORIF and bone grafting may be indicated in functionally high-demand patients to prevent adaptive carpal instability and possible midcarpal arthritis (Fig. 7.14).
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Wrist arthritis: Associated with residual intraarticular step-off, but often does not necessarily correlate with patient-reported symptoms.
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Tendon injury: Reported after volar (flexor and extensor) and dorsal plating (extensor)
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FPL: Tendon most commonly ruptured after volar plating; potentially due to improper plate placement distal to watershed zone
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EPL: Extensor tendon most commonly injured; potentially due to drill-bit penetration or dorsally prominent screws
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CRPS: Vitamin C in doses of at least 500 mg/day for 50 days, in patients with normal renal function, may decrease the incidence of CRPS in women older than 50 years who are treated for a distal radius fracture, although this issue is controversial because new evidence disputes early reports.
Review Scaphoid fractures
Most common carpal fractures, accounting for up to 15% of acute wrist injuries
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Anatomy of scaphoid
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Approximately 75% covered by articular cartilage
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Blood supply
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Main (proximal ¾) supply from dorsal branch of the radial artery enters at dorsal ridge just distal to waist and flows in retrograde fashion toward proximal pole.
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Distal ¼: Superficial volar branches of radial artery enter at distal tubercle
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Danger: Tenuous and retrograde vascular supply puts waist and proximal pole fractures at risk for nonunion and posttraumatic osteonecrosis.
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Diagnosis
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Mechanism: Forced hyperextension and radial deviation of the wrist
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Presentation: Swelling, anatomic snuffbox/volar tubercle tenderness, limited wrist and/or thumb motion
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Radiographs: Standard wrist radiographs; additional scaphoid view—approximately 30 degrees of wrist extension and 20 degrees of ulnar deviation—displays scaphoid in best profile
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Radiographs initially nondiagnostic in more than 30% of cases
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If normal radiographic findings and high clinical suspicion, arm should be immobilized and physical examination and radiographs should be repeated in 2 weeks, or MRI should be obtained immediately.
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Advanced imaging: Bone scan, ultrasonography, CT, and MRI have all been used for earlier diagnosis.
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All advanced imaging modalities are better for ruling out rather than ruling in a scaphoid fracture.
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MRI has highest sensitivity, specificity, and accuracy (all >95%) with high positive and negative predictive values at less than 24 hours.
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Missed fracture: Failure of identification and immobilization for more than 4 weeks after fracture increases nonunion rate almost tenfold.
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Classification
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Locations (Fig. 7.15)
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Tubercle, distal pole, waist (most common), proximal pole
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Distal pole is most common in skeletally immature patients
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Stability
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Stable fractures: Transverse pattern, minimal comminution, and limited displacement
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Unstable fractures: Vertical or oblique patterns, significant comminution, and wide displacement
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CT: Required for determining displacement and stability
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Treatment
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Nonoperative
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Cast immobilization for nondisplaced fractures
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No difference in the type of cast for union, with similar outcomes seen in long-arm vs. short-arm and standard vs. additional thumb spica component
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Time to union: Increases as the fracture location becomes more proximal.
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Consequently, length of cast immobilization should be greater for more proximal fractures.
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CT is best modality to assess union rates after treatment.
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Operative
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Indications: proximal pole fracture, more than 1 mm displacement, intrascaphoid angle more than 35 degrees (humpback deformity), comminuted or vertical/oblique fracture, and transscaphoid perilunate dislocation
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Faster time to union and return to work in nondisplaced waist fractures with operative than with nonoperative management
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Minimally displaced fractures: May be treated with percutaneous internal fixation using a headless compression screw
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Displaced fractures: Formal ORIF via dorsal or volar approach
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Most critical technical factor: Guide-pin placement should be within the central axes of both the proximal and distal fragments.
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Approach: Volar and dorsal approaches have equivalent outcomes. In general, the dorsal approach is used for proximal pole fractures and the volar approach for distal pole injuries.
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Outcomes: Union rates of more than 90% expected with surgical treatment
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CT confirmation of union necessary before physical therapy is begun
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Complications
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Nonunion: Diagnosed on CT
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Symptomatic early-stage scaphoid nonunion may be treated with ORIF and bone grafting (using distal radius or iliac crest) (Fig. 7.16).
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Vascularized proximal pole: Inlay (Russe) technique used in cases with minimal deformity
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Best diagnosed with presence of intraoperative punctate bleeding
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Humpback deformity: Requires open-wedge interposition structural graft to restore scaphoid length and carpal alignment
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Vascularized bone grafting has a role in nonunion with an avascular proximal pole.
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Bone most commonly harvested from dorsal aspect of distal radius, based on 1,2 intercompartmental supraretinacular artery (1,2 ICSRA)
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For correction of both humpback deformity and avascular proximal pole: Free transfer of medial femoral condyle bone graft, supplied by descending medial genicular, and connected end-to-side to radial artery
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Scaphoid nonunion advanced collapse (SNAC) wrist: Untreated, chronic scaphoid nonunion may lead to characteristic progression of posttraumatic osteoarthrosis
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Stage I—radioscaphoid arthritis
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Stage II—involvement of the scaphocapitate joint
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Stage III—involvement of the lunocapitate joint
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Options for treatment of SNAC wrist include radial styloidectomy, distal scaphoid resection (Malerich procedure), proximal row carpectomy (PRC), scaphoid excision and four-corner (bone) fusion, and total wrist fusion, depending on stage of presentation and surgeon preference (Figs. 7.17 and 7.18).
DISI
carpal instability
DISI: Most common form of carpal instability; lunate and triquetrum tilt dorsally (see Fig. 7.9)
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Etiology: SL ligament disruption
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Dorsal fibers are stronger than volar fibers.
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DISI develops after secondary injury to stabilizing dorsal and/or volar extrinsic ligaments, volar scaphotrapeziotrapezoid (STT) ligaments
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Mechanism: Scaphoid hyperflexion and lunate hyperextension
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May be traumatic or may result from inflammatory or crystalline arthropathy
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Physical examination: Dorsal wrist pain with loading, diminished grip strength
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Watson shift test: Reproduction of pain/palpable clunk with scaphoid shift test (dorsally directed pressure over volar scaphoid tubercle while wrist is brought from ulnar to radial deviation subluxates or dislocates scaphoid over dorsal ridge of distal radius that, when released, causes scaphoid to reduce with painful clunk)
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Bilateral nonpainful clunks constitute a negative test result.
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Diagnosis
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Radiographs: Cortical ring sign showing flexion of the scaphoid, increased scapholunate angle (>70 degrees), or widened scapholunate interval (>3 mm).
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Pencil test or bilateral clenched-fist (AP grip) comparison views: Dynamic DISI with relatively widened scapholunate interval on affected side (stress radiographs)
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MRI: Best but not perfect for detection of SL ligament injury
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Wrist arthroscopy: Gold standard to diagnose any wrist ligament injury (including SL)
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Geissler classification (Table 7.2)
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Treatment: Depends on stage of instability
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Partial ligament injuries (predynamic or dynamic instability): Nonoperative treatment or arthroscopic débridement.
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For acute SL ligament rupture: Rarely amenable to primary repair alone
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After delayed diagnosis of SL ligament rupture: Open reduction of scapholunate interval and K-wire pinning with or without dorsal capsulodesis or tendon autograft reconstruction
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Various tendon (e.g., Brunelli) and bone-retinaculum-bone grafts have also been attempted for SL reconstruction.
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Limited clinical data on reduction-association of scaphoid and lunate (RASL) procedure or other forms of implants to span SL joint
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Scapholunate advanced collapse (SLAC): Chronic untreated static SL instability
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Fig. 7.23 illustrates the three stages.
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Radiolunate joint is often spared.
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Treatment: Depends on condition of articular surfaces and competency of the radioscaphocapitate ligament.
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Options include radial styloidectomy, PRC, scaphoid excision with four-corner arthrodesis, isolated capitolunate arthrodesis, and total wrist arthrodesis.
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Partial wrist denervation: Excision of the terminal branch of the PIN ± AIN is often done in conjunction with these procedures but is also an option on its own.
Review VISI, and other less common
carpal instability
Second most common form of carpal instability; lunate and scaphoid tilt volarly (see Fig. 7.9)
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Disruption of LT interosseous ligament
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Volar fibers are stronger than dorsal fibers.
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Static instability: Accompanying injury of the dorsal extrinsic ligaments (dorsal radiocarpal and intercarpal ligaments)
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Physical examination
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Ulnar-sided wrist pain
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Lunotriquetral shear or shuck test
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Diagnosis
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Radiographic findings: Break in Gilula arc on posteroanterior view and scapholunate angle decreased to less than 30 degrees on lateral view
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MRI may show pathology of LT ligament.
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Wrist arthroscopy: Gold standard
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Treatment
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Direct volar lunotriquetral ligament repair
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FCU tendon augmentation
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Lunotriquetral arthrodesis
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Ulnar shortening osteotomy for patients with concurrent ulnocarpal impaction syndrome
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Midcarpal carpal instability nondissociative (CIND)
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Clunking wrist that may or may not be painful
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Many patients have generalized ligamentous laxity.
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History of trauma often absent
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Sudden shift of proximal carpal row with active ulnar deviation
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Nonoperative management, including hand therapy and proprioceptive training, should be maximized.
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Midcarpal fusion preferred over soft tissue reconstructions in patients in whom non-operative treatment fails, because the latter repair may stretch out.
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Radiocarpal dislocation (CIND)
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Rare, high-energy injury
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“Inferior arc” injury
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May be associated with intracarpal injury, acute carpal tunnel syndrome, possible compartment syndrome, other major musculoskeletal and/or organ injuries
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May be purely ligamentous or include radial and/or ulnar styloid fractures
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Ulnar translocation of the carpus signifies global ligamentous disruption.
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The affected ligaments are:
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Volar extrinsic ligaments (in order, radial to ulnar): Radioscaphocapitate, long radiolunate, short radiolunate, and radioscapholunate (also termed ligament of Testut—vestigial neurovascular contents)
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Ulnocarpal ligaments: Ulnolunate, ulnotriquetral, and ulnocapitate
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ORIF of radial styloid fractures may reduce ulnar translocation of the carpus by restoring radioscaphocapitate ligament stability.
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May also require direct ligamentous repair and/or external fixation or bridge plate to neutralize forces
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Associated intracarpal injuries treated simultaneously
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Carpal instability adaptive from distal radius malunion
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May result from deformities with more than 30 degrees of dorsal angulation in the sagittal plane
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Concern for midcarpal pain/arthritis
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Treated with corrective osteotomy of the distal radius
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Perilunate dislocations (carpal instability complex)
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Potentially devastating injuries resulting from forced dorsiflexion, ulnar deviation, and intercarpal supination
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Approximately 25% of cases may be missed in the emergency department due to poor radiographs and lack of awareness. Key is to analyze the three Gilula lines on an AP plain radiograph.
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Mayfield described four stages of perilunar disruption of ligamentous constraints, proceeding in counterclockwise direction
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Stage I: Scapholunate disruption
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Stage II: Capitolunate disruption
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Stage III:
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Lunotriquetral disruption
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Dorsal midcarpal dislocation
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Capitate appears dorsal to lunate on lateral view
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Stage IV:
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Circumferential disruption
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Volar lunate dislocation: Osteonecrosis of the lunate avoided because of attached volar extrinsic (short radiolunate) ligament that maintains blood supply (Fig. 7.24)
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Lesser-arc injuries: Purely ligamentous
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Greater-arc injuries: Carpal fracture (transscaphoid most common)
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Treatment: Prompt attempt at closed reduction, especially in setting of acute carpal tunnel syndrome
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Stable closed reduction may allow for delayed definitive surgical management, but there is no role for closed treatment alone.
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Irreducible injuries necessitate urgent operative intervention.
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ORIF may require dorsal and/or volar approach.
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Combination of ligamentous repair, fracture fixation, dorsal capsulodesis, and K-wire pinning of proximal row and midcarpal joint (Fig. 7.25)
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Carpal tunnel release for associated acute carpal tunnel syndrome
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Cast immobilization for 2–3 months
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Late diagnosis leads to consistently poor outcomes
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Methods of treating delayed and chronic perilunate dislocations are controversial.
what are the volar extrinsic ligaments in order?
Volar extrinsic ligaments (in order, radial to ulnar): Radioscaphocapitate, long radiolunate, short radiolunate, and radioscapholunate (also termed ligament of Testut—vestigial neurovascular contents)
Review metacarpal shaft fractures
Transverse, oblique, or spiral
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Higher risk of malrotation: 5 degrees of malrotation results in 1.5 cm of digital overlap.
•
Acceptable angulation/shortening of each metacarpal shaft
•
Index/long: less than 10 degrees
•
Ring/small: less than 30 degrees
•
All: less than 5 mm of shortening is acceptable without significant functional deficit.
•
Every 2 mm of metacarpal shortening leads to 7 degrees of extensor lag.
•
Irreducible displaced fractures: CRPP or ORIF
•
Intramedullary pinning: Antegrade or retrograde
•
Lag screw fixation: Fracture length twice the bone diameter
•
Dorsal plates: Prominent dorsal plates irritate or injure extensor tendons.
•
Multiple metacarpal shaft fractures are unstable injuries that often necessitate surgical intervention.
Review metacarpal head and neck fractures
Most commonly occurs in the index or middle finger
•
Some condylar injuries represent ligamentous avulsions
•
Surgical treatment
•
More than 1 mm of articular step-off: ORIF
•
Open fight bites: Early surgical débridement and assessment of extensor mechanism injury
•
Severe open or comminuted fractures (e.g., gunshot wounds): Spanning external fixation.
•
Severe comminuted closed fractures: Arthroplasty or arthrodesis (especially index MCP)
•
Joint stiffness: most common complication with both nonoperative and operative treatment.
□
Metacarpal neck fracture
•
Weakest portion of metacarpal
•
Most frequently involves the ring and small fingers
•
Boxer’s fracture: Metacarpal neck fracture of the small finger
•
Deforming forces: Intrinsic muscles lead to apex dorsal angulation.
•
Examiner should check for malrotation, pseudoclawing, and MCP joint extensor lag.
•
Nonoperative treatment: Most cases can be treated with closed reduction (dorsal pressure or Jahss maneuver) and 3–4 weeks of immobilization.
•
Acceptable angulation of each metacarpal neck
•
Index/long: less than 15–20 degrees
•
Ring: less than 30–40 degrees
•
Small: less than 60–70 degrees (controversial)
•
Greater compensation from more mobile fourth and fifth carpometacarpal (CMC) joints
•
Irreducible fractures: CRPP (antegrade, retrograde, or transverse)
Metacarpal base fractures
including thumb
Metacarpal base fracture and CMC joint dislocation
•
Stable, minimally displaced fractures of metacarpal base are treated nonoperatively.
•
Ring and small CMC joint fracture-dislocations often result from higher-energy mechanisms.
•
Radiographs: Pronated 30-degree oblique view
•
CT: For complex injuries
•
Small-finger CMC joint fracture-dislocation is termed a reverse or baby Bennett fracture.
•
Extensor carpi ulnaris (ECU) tendon is major deforming force.
•
Accompanying distal row carpal fractures may be seen, especially of the hamate and capitate, which can signify high-energy mechanism.
•
Closed reduction may be attempted, but these are unstable injuries that often require surgical stabilization via CRPP or ORIF. Over the fourth and fifth CMC joints, care must be taken not to injure the dorsal sensory branch of the ulnar nerve during open approaches.
•
Delayed treatment, painful malunion, or posttraumatic osteoarthrosis may require arthrodesis.
□
Thumb metacarpal fracture
•
Most common pattern is extraarticular basilar fracture.
•
Acceptable angulation: Up to 30 degrees, secondary to compensatory CMC joint motion
•
Excessive angulation: MCP joint hyperextension, requiring CRPP or ORIF
•
Mnemonic for reduction maneuver is TAPE: traction, abduction, pronation, and extension of thumb metacarpal (©Kakar).
•
Bennett fracture: Intraarticular fracture-dislocation (Fig. 7.26)
•
Deforming forces: Abductor pollicis longus (APL) and thumb extensors cause proximal, dorsal, and radial displacement of the metacarpal shaft.
•
APL causes supination and adduction of the metacarpal shaft.
•
Anterior oblique or “beak” ligament keeps the volar-ulnar base fragment reduced to the trapezium.
•
Treatment: CRPP or ORIF based on the size of fragment
•
Reduction: Traction, palmar abduction, and pronation
•
Goal: More than 1–2 mm of articular step-off
•
Rolando fracture: Comminuted intraarticular fracture (T or Y shape) (Fig. 7.27)
Review GameKeeper’s Thumb
Injuries: Acute (skier’s thumb) or chronic (gamekeeper’s thumb) injury to the ulnar collateral ligament (UCL) of the thumb via supination of the proximal phalanx around intact RCL
•
UCL function is critical for strong, effective pinch.
•
Mechanism of injury: Forceful thumb hyperextension and/or hyperabduction
•
Spectrum of injury: Dorsal-to-volar, involving proper UCL, accessory UCL, and volar plate. Ligament injury tends to occur at its insertion at the base of the proximal phalanx.
•
Radiographs: Obtained prior to stress examination to rule out bony avulsion injury.
•
MCP stress test (in the absence of fracture): MCP joint is stressed with radial deviation both in neutral and in 30 degrees of flexion.
•
Instability in 30 degrees of flexion: Proper UCL and/or dorsal capsule injury
•
Instability in neutral: Accessory UCL and/or volar plate injury
•
Threshold: More than 35 degrees of opening or more than 20 degrees of difference from opening of uninjured thumb
•
Complete vs. partial tears: Difficult to differentiate by physical examination alone
•
Diagnosis: Stress radiographs and/or MRI
•
Partial injuries: Treated with thumb spica cast immobilization for 4–6 weeks.
•
Stener lesion: Occurs in 85% of complete injuries when the adductor pollicis aponeurosis is interposed between the avulsed UCL and its insertion site on the base of the proximal phalanx (Fig. 7.28)
•
Treatment: Surgical reattachment of ligament through drill holes, suture anchor, or interference screw.
•
Large displaced avulsion fracture of the base of the proximal phalanx: Requires ORIF
•
Chronic UCL injuries: Ligament reconstruction with either adjacent joint capsule or tendon graft, ± pinning of joint.
•
Posttraumatic osteoarthrosis: MCP arthrodesis
•
Radial collateral ligament (RCL) injury: RCL instability is due to overpull of adductor, which causes proximal phalanx to pronate around intact RCL. It is much more rare than the UCL tears, but has a similar evaluation and treatment approach.
•
Isolated injuries to the thumb MCP radial collateral ligament: After a forced flexion-ulnar deviation mechanism
•
Nonoperative treatment in most cases
•
Surgery: For high-grade or complete tears associated with volar MCP subluxation. Ligament injury tends to occur at its origin at the metacarpal.
What is Kaplan’s lesion?
An irreducible dorsal MCP joint dislocation with volar plate interposition
how do you treat simple PIP joint dislocations after reductions?
simple buddy taping
Finger Fracture/Dislocations
Dorsal dislocation accompanied by fracture at P2 base (Fig. 7.29)
•
Hastings classification based on amount of P2 articular surface involved (Table 7.3)
•
Treatment
•
Dorsal block splinting, dorsal block pinning, ORIF, or hemihamate reconstruction
•
More than 30% of involvement of the base of the proximal phalanx tends to lead to persistent dorsal subluxation of the PIP joint; surgical reconstructions such as volar plate arthroplasty and hemihamate transfer aim at restoring the volar buttress to dorsal displacement.
•
Maintenance of adequate joint reduction is most important factor for favorable long-term outcome.
•
Chronic PIP fracture-dislocations without severe posttraumatic osteoarthrosis: Hemihamate reconstruction or volar plate arthroplasty, depending on functional demands of the patient.
•
PIP posttraumatic arthritis: Silicone arthroplasty or arthrodesis
•
Highly comminuted pilon fractures are best handled with dynamic distraction external fixation for simple ligamentotaxis and early ROM.
□
DIP dislocation and distal phalanx fractures
•
Reducible DIP dislocation: Closed reduction and immobilization in slight flexion with a dorsal splint for 2 weeks
•
Irreducible DIP dislocation: Caused by interposition of the volar plate
•
Treatment: Open reduction and extraction of the volar plate
•
Stable tuft fracture (common): No specific treatment apart from temporary splinting
•
Open injuries: Irrigation and débridement, reduction, nail bed repair (if necessary), antibiotics, tetanus prophylaxis, and splinting
•
Unstable displaced fractures of the distal phalanx: Percutaneous pinning to support the nail bed repair
•
Common associated injuries: Soft tissue and/or nail bed disruption
•
Highly comminuted injuries with significant soft tissue loss: Revision amputation (shortening and closure)
•
Seymour fracture: A transverse physeal injury that may become displaced and require extraction of interposed nail matrix to prevent malunion. This is considered an open fracture.
•
For further details see the section Nail and Fingertip Injuries.
Extensor Tendon Injuries
Zone I injury (mallet finger)
•
Location: Terminal extensor tendon at or distal to DIP joint
•
Mechanism: Sudden forced flexion of the extended fingertip
•
Presentation: Patient cannot actively extend at DIP joint, and finger remains in flexed posture.
•
Bony mallet: Bony avulsion injury from dorsal base of P3 (bony mallet)
•
Nonoperative treatment: If detected less than 12 weeks of injury
•
DIP joint extension splinting for 6 weeks, followed by part-time splinting for an additional 4–6 weeks
•
No proven best type of splint
•
Hyperextension should be avoided because it can cause skin necrosis.
•
Maintenance of PIP joint motion often overlooked
•
Nondisplaced bony mallet finger: Extension splinting until fracture union
•
Displaced bony mallet finger: Controversial surgical indication
•
Treatment options: CRPP through DIP joint or extension block pinning if there is joint subluxation on the lateral radiograph or >50% articular surface
•
Chronic mallet finger (>12 weeks after injury)
•
Closed treatment: If joint supple, congruent, and without arthritic changes
•
Dynamic splinting + serial casting: Contracted joint
•
Operative treatment: Tenodermodesis, Fowler tenotomy
•
Prolonged DIP flexion: Associated with swan neck deformity from dorsal subluxation of lateral bands and corresponding PIP joint hyperextension
•
Supple swan neck deformities may be treated with
•
Fowler central slip tenotomy (maximum deformity 35 degrees), which allows the extensor apparatus to slide proximally, thereby increasing its effective pull at the DIP joint.
•
Boutonnière deformity is prevented by not injuring the triangular ligament, thereby keeping the lateral bands dorsal of the midline in the sagittal plane.
•
Spiral oblique retinacular ligament (SORL) reconstruction
•
DIP joint arthrosis: DIP arthrodesis.
•
Zone II injury
•
Location: Middle phalanx of digit or over proximal phalanx of thumb
•
Mechanism: Dorsal laceration or crush component
•
Partial disruptions (<50%): Local wound care and early mobilization
•
Lacerations more than 50%: Direct surgical repair
•
Controversial: Temporary pinning across terminal joint after direct repair
•
Zone III injury (boutonnière)
•
Location: PIP joint of digit (central slip) or MCP joint of thumb
•
Open injuries: Directly repaired if possible
•
Loss of tendon substance: Free tendon graft or extensor mechanism turndown flap
•
Elson test: Examiner performs by flexing the patient’s PIP joint 90 degrees over the edge of a table and asking patient to extend the PIP joint against resistance.
•
Central slip intact: The DIP joint will remain supple as the power of extension is focused at the central slip insertion with the lateral bands remaining lax.
•
Central slip rupture: The DIP joint will be rigid as the power of extension is diverted to the lateral band rather than the central slip.
•
Acute boutonnière deformity: Results from central slip disruption and volar subluxation of the lateral bands, resulting in DIP hyperextension (Fig. 7.31)
•
Closed injury: Full-time PIP extension splinting for at least 6 weeks, followed by part-time splinting for an additional 4–6 weeks.
•
DIP flexion maintained to balance extensor mechanism by encouraging the lateral bands to drift dorsal of the midline in the sagittal plane.
•
Chronic (untreated) boutonnière deformity
•
May require dynamic splinting or serial casting to achieve maximal passive motion first
•
Terminal extensor tenotomy, PIP volar plate release
•
Central slip reconstruction techniques: Tendon graft, extensor turndown, lateral band mobilization with transverse retinacular ligament release
•
PIP joint arthrosis: PIP arthrodesis
•
Zone IV injury
•
Location: Proximal phalanx of digit or over the metacarpal of thumb
•
Treatment: Similar to that for injuries in zone II
•
Common complication: Adhesion formation leading to loss of digital flexion
•
Prevention of adhesion formation: Early protected ROM and dynamic splinting
•
Failure of nonoperative management may require extensor tenolysis.
•
Zone V injury
•
Location: MCP joint of digit or over CMC joint of thumb
•
Treatment (most): Early mobilization and dynamic splinting
•
Fight bite: Surgical débridement of the MCP joint with loose or delayed wound closure
•
Most common organism: Eikenella corrodens
•
Extensor lag and loss of flexion are common.
•
Sagittal band rupture (flea-flicker injury): From forced extension of flexed digit
•
Long finger most commonly injured
•
Rupture of the stronger radial fibers may lead to extensor tendon ulnar subluxation/dislocation.
•
Finger will be held in flexed position at MCP joint with no active extension.
•
Passive extension of the MCP joint is possible, and the patient can then usually maintain the finger in an extended position.
•
Treatment
•
Acute injuries: 4–6 weeks of extension splinting of the MCP joint (one of the only exceptions to splinting the MCP joints in flexion).
•
Failure of nonoperative management or missed injuries: Repair or reconstruction of the sagittal band
•
Zone VI injury
•
Location: Metacarpal and represents most frequently injured zone
•
Associated injuries: Lacerations of superficial veins and nerves
•
Laceration more than 50% tendon: Direct surgical repair
•
Early protected motion advocated postoperatively
•
Dynamic splinting may offer better short-term ROM and strength, without increased complications, than static splinting.
•
Good prognosis is good in the absence of concurrent bony injury.
•
Zone VII and VIII injuries
•
Location: Level of the wrist joint (VII) and distal forearm at the musculotendinous junction (VIII)
•
Lacerations at wrist level are usually associated with extensor retinaculum disruption, and postoperative adhesions are common.
•
Treatment
•
The retinaculum should be repaired to prevent tendon bowstringing.
•
Static immobilization with the wrist held in extension and the MCP joints partially flexed for the first 3 weeks, followed by protected motion
•
The results of surgical repair in these zones are not as good as those in zones IV, V, and VI.
Review the pathoanatomy of a boutinear’s deformity:
Elson’s test
Pathomechanics of the boutonnière deformity. (A) Attenuation of the central slip results in unopposed flexion at the PIP joint. (B) With PIP joint flexion, the lateral bands drift volar to the axis of rotation at the PIP joint. The lateral bands stay in the volar position owing to loss of dorsal support from the attenuated triangular ligament and contracture of the transverse retinacular ligament.
Flexor tendon injury
Overview
•
Concomitant neurovascular injury is common when associated with lacerations.
•
Physical examination: Examiner should note the resting posture of the hand and check the tenodesis effect with passive wrist flexion and extension.
•
Each digit should be tested in isolation for active DIP (FDP function) and PIP flexion (FDS function).
•
Treatment
•
Partial lacerations may be associated with gap formation or triggering with nonoperative treatment
•
Triggering treatment: Trimming tendon ends or performing epitendinous repair
•
Lacerations more than 60% tendon width: Simultaneous core and epitendinous repair within 3 weeks (ideally <10 days of injury)
□
Basic surgical techniques of flexor tendon repair
•
Strength of repair proportional to number of suture strands that cross repair site (core sutures)
•
6–8 strands have superior strength and stiffness
•
High-caliber (e.g., 5-0 instead of 6-0) suture material decreases gap formation and increases strength and stiffness.
•
A locking-loop configuration decreases gap formation.
•
Epitendinous repair decreases gap size and increases overall strength by 10%–50%.
•
Purchase, defined as the longitudinal distance from cut tendon end to transverse component of the core suture, should be 0.7–1.2 cm.
•
Dorsally placed core sutures are stronger.
•
Repair of the flexor tendon sheath has no effect on flexor tendon repair.
•
Atraumatic, minimal-touch technique minimizes adhesions.
•
A2 (most important) and A4 pulleys (oblique pulley in thumb) must be preserved to prevent bowstringing.
•
Risk of tendon rupture greatest 3 weeks after repair; failure typically occurs at suture knots.
•
Wide awake local anesthesia no tourniquet [WALANT] (uses lidocaine withepinephrine) allows one to perform flexor tendon repair with the patient wide awake to allow testing of the integrity of the repair.
•
Early protected ROM is thought to increase tendon excursion, decrease adhesion formation, and increase repair strength.
•
Postoperative use of an active flexion protocol requires a minimum four-strand repair with epitendinous suture.
•
Young children cannot comply with protected motion protocols so require cast immobilization for 4 weeks.
□
Tendon healing factors
•
Intrinsic healing is directed by tendon fibroblasts (tenocytes)
•
Extrinsic healing potential is limited
•
Only small contribution from repair cells within tendon sheath or from vascular invasion
•
Tendon healing is strongly influenced by biomechanical stimuli, and early mobilization has been shown to decrease adhesion formation and increase the strength of repair tissue.
•
No definitive evidence of growth factor or stem cell augmentation of healing
□
Treatment according to Verdan zones (Fig. 7.32)
•
Zone I injury (rugger jersey finger)
•
Location: FDP avulsion distal to the FDS insertion
•
Tendons involved: FDP only
•
Mechanism: Forced extension of the DIP joint during grasping
•
The ring finger is involved in 75% of cases.
•
Classification: Leddy and Packer (Fig. 7.33)
•
Type I: FDP is retracted to the palm; requires direct repair within 7–10 days.
•
Type II: May be directly repaired up to 6 weeks later because the intact vincula prevent FDP retraction proximal to the PIP joint
•
Type III: Associated with small bony avulsion fragment with minimal retraction as the fragment is caught upon the pulley; may be successfully repaired up to 6 weeks after injury
•
Type IV: FDP is avulsed off bony fragment and as such can retract proximally and requires expeditious repair (rare subtype).
•
Key point: Profundus advancement of 1 cm or more carries a risk of DIP joint flexion contracture or quadrigia.
•
Quadrigia: FDP tendons (middle, ring, small) have a common muscle belly, so distal advancement of one tendon compromises flexion of the adjacent digits, because the advanced FDP tendon has greater tension in comparison with the laxity of the adjacent FDP tendons. As such, when the advanced FDP tendon contracts, the efficiency of contraction of the adjacent FDPs is decreased, resulting in decreased DIP joint motion of the adjacent digits.
•
Full PIP flexion in chronic injuries: Treated with observation or DIP arthrodesis in a functional position
•
Intact FDS function should never be sacrificed to permit reconstruction of an injured FDP tendon.
•
Two-stage flexor tendon reconstruction with silicone rod can be considered in young motivated patients, although the results can be unpredictable.
•
Zone II (“no man’s land”) injury
•
Location: Between the FDS insertion and the distal palmar crease within flexor tendon sheath
•
Tendons involved: Both the FDS and FDP may be injured.
•
Key point: Tendon lacerations may be at a different level from that of the skin laceration, depending on the position of the finger when the laceration occurred.
•
Treatment: Direct repair of both tendons with a core and epitendinous suture technique followed by an early mobilization protocol
•
Outcomes: Historically poor owing to the high rate of adhesion formation at the pulleys and associated digital neurovascular injuries
•
Although advances in postoperative rehabilitation have improved the clinical outcomes, up to 50% of patients require subsequent tenolysis to enhance active motion at least 3 months after repair.
•
Zone III injury
•
Location: Occurs between the distal palmar crease and the distal end of the carpal tunnel
•
Tendons involved: Both FDP and FDS can be injured.
•
Treatment: In comparison with results of zone II injuries, those of direct repair are much better owing to a lack of the pulley system and hence fewer adhesions.
•
Key point: Lumbrical muscles originate from the radial aspect of FDP tendons in zone III.
•
Zone IV injury
•
Location: Within the carpal tunnel
•
Zone V injury
•
Location: Between proximal carpal tunnel and musculotendinous junction
•
Treatment: Direct repair in this zone has a favorable prognosis.
•
Outcomes: Results may be compromised by coexisting nerve injury.
□
FPL injury
•
Zone I injuries: Distal to IP joint
•
Zone II injuries: Between IP and MCP joints
•
Zone III injuries: Deep to thenar muscles
•
Postoperative rehabilitation
•
Two most common rehabilitation protocols are those of Kleinert and Duran.
•
Kleinert protocol: Dynamic splinting, allowing for active digit extension and passive digit flexion
•
Duran protocol: Other hand used to perform passive digital flexion exercises
•
Requires strict patient compliance
•
Both protocols: Avoidance of active flexion for 6 weeks
•
Newer advancements: Components of early active digital flexion added to reduce adhesion formation and increase tendon excursion
•
These protocols require stronger repair methods (i.e., use of a minimum of four core sutures).
□
Flexor tendon reconstruction
•
Indication: Failed primary repair or chronic, untreated injuries
•
Requirements: Supple skin, a sensate digit, adequate vascularity, and full passive ROM of adjacent joints
•
The majority of cases require two-stage reconstruction.
•
Stage I: Implantation of a temporary silicone (Hunter) rod that is secured distally but allowed to glide proximally to recreate a “tunnel” for the new tendon to glide through
•
A2 and A4 pulleys preserved or reconstructed
•
Stage II: Performed more than 3 months later, once full passive ROM has been attained and a sheath has formed around the silicone rod.
•
Rod is removed and tendon autograft is passed through the sheath
•
Grafts
•
Extrasynovial (e.g., palmaris longus or plantaris): Act as scaffold to allow tenocytes infiltration and collagen deposition
•
Intrasynovial (e.g., FDS): Retain their gliding surface and heal intrinsically
•
Postoperative rehabilitation: Despite the need for an intensive program, subsequent tenolysis is often required (>50%).
Trigger finger classification
Stress test of the the thumb UCL
gamekeepers/skier thumb
Instability in Neutral–Accessory UCL and or volar plate
Instability at 30 degrees–Proper UCL and or dorsal capsular injury
Threshold–more than 35 degrees of opening, or 20 degrees compared to the other side
Extensor Tendon Pearls
less than 50% or active extensionneeds no repair and are treated with early protected motion
Zone 1 = Mallet finger
Zone 3 = Boutonniere
Zone 5 = Fight bite or saggital band rupture
Zone 7 = extensor retinaculum disruption
Flexor tendon injury overview
Flexor tendon Zone 1 Injuries
Jersey Finger
Profudus advancement of 1cm or more carries a risk of DIP joint flexion contracture or quadrigia
Type 1 requires repair within 7-10 days
Type 2 can be repaired wihtin 6 weeks due to vinicular blood supply
Type 3 bony avulsion–direct repair within 6 weeks
what is quadrigia
two stage flexor tendon reconstruction with silicone rod can be consided in young motivated patients, although the results can be unpredictable.
Zone 2 Flexor tendon injuries
no mans land
located between the fds insertion and the distal palmar crease
note: tendon lacerations may be at different levels from that of the skin laceration, depending on the position of the finger when the laceration occured
TREATMENT: direct repair with epitendinous suture repair followed by an early motion protocol
upto 50% require furter tenolysis
Flexor tendon post-operative rehab protocols:
Kleinert Protocol:Dynamic splinting, allowing for active digit extension and passive digit flexion
Duran Protocol:The other hand is used to perform passive digital flexion exercises (i.e Duran Duran)
both protocols avoid active flexion for 6 weeks
require minimum of 4 core sutures
Flexor Tendon Reconstruction
Indicated for failed primary repair or chronic unreated injuries
requires supple skin, a sensate digit, and full PROM of adjacent joints
TWO-Staged reconstruction:
temporary silicone rod to create tunnel
Stage two is performed three months later, once full prom has beedn attanted and a sheath has formed around the silicone rod. Tendon autograft is passed through the tunnel
Trigger Finger
injection currative in 50%
not so good in diabetics
surgical release of A1 pulley, may have to resect ulnar FDS slip
Radial digital nerve at risk of iatrogenic injury during release given its superficial location
Pediatric Trigger Thumb
Notta Node: pathologic nodular tendon thickening, not seen in adults
treat with observation first, then at 2-4 years, annular pully release to prevent IP joint contracture
radial digital nerve at risk during release
A1 pulley release may not resolve triggering; additional a3 release or resection of ulnar FDS slip may be required
Dequervain tenosynovitis
attritional and degenerative condition affecting the first compartment, APL, EPB
Intersection syndrome
tenosynovitis and/or bursitis occuring at the junction of the first and second extensor tendon compartments
Rowers, lineman, golfers,
localized to an area 4-5 cm proximal to the radiocarpal joint
surgically release second compartment and debride inflamed bursa
Acute Calcific Tendonitis
Usually FCU, can be FCR
digital partial amputation flap options
Moberg Advancement Flap
Review the technique of a cross finger flap
Review the standard 60 degree z plasty
Limbs should always be equal, but the flap cut angles may vary to change the amount of desired lengthening—30 degrees for 25% lengthening, 45 degrees for 50%, and 60 degrees for 75%
Review of replantation
Indications and contraindications
•
Primary indications for attempting replantation
•
Thumb
•
Multiple digits
•
Wrist level or proximal
•
Any amputation in child
•
Relative indication: Amputation level distal to the FDS insertion (zone I)
•
Primary contraindications to replantation
•
Single digit amputation, especially index
•
Crushed or mangled amputated parts, arterial ribbon sign
•
Prolonged ischemia
•
Segmental amputations
•
Level of amputation within zone II flexor tendon sheath, because of pain and stiffness
•
Poor candidates for replantation: patients with multisystem traumatic injuries and those with multiple medical comorbidities or disabling psychiatric conditions
□
Care of the amputated part
•
Wrapped in moist gauze (normal saline or lactated Ringer’s solution) and placed within a sealed plastic bag in an ice-water bath.
•
Replantation is not recommended for (controversial):
•
Warm ischemia time is more than 6 hours for an amputation level proximal to the carpus or more than 12 hours for an amputated digit
•
Cold ischemia time of more than 12 hours for an amputation level proximal to the carpus or more than 24 hours for an amputated digit
□
Operative sequence of replantation (mnemonic: BEFAVNS)
•
Bone stabilization, usually with shortening
•
Extensor tendon repair
•
Flexor tendon(s) repair
•
Arterial reanastomosis
•
Venous reanastomosis
•
Nerve repair
•
Skin approximation (loose)
•
If multiple digits, priority sequence is thumb > long > ring > small > index
•
Thumb provides 40% of hand function.
•
Structure-by-structure technique faster and yields higher viability rate than finger-by-finger technique.
•
Use of venous couplers may result in shorter operative times and less vasospastic collapse of the anastomosis.
•
Postoperative care
•
Warm environment (≈80°F)
•
Adequate hydration
•
Pain relief to prevent sympathetic surge and vasoconstriction
•
Aspirin
•
Dextran/heparin controversial
•
Thorazine acts as both vasodilator and anxiolytic (especially good for children)
•
Prohibition of nicotine, caffeine, other vasoconstricting agents
•
Replantation monitoring
•
Most reliable method is close observation of color, capillary refill, and tissue turgor.
•
Monitoring techniques: Measurement of oxygen saturation by pulse oximetry and of skin surface temperature
•
A drop in temperature of more than 2°C in 1 hour and a temperature of less than 30°C both indicate decreased digital perfusion.
•
Invasive alternative: Placement of implantable venous Doppler probe
•
Length of monitoring: 4–5 days
•
Complications
•
Early (<12 hours) replantation failure: Due to arterial thrombosis from persistent vasospasm
•
Diagnosis: Pale skin color, decrease or absence of capillary refill, loss of ultrasound-measurable signal
•
Initial treatment: Release of constricting bandages, placement of extremity in dependent position, administration of heparin, stellate ganglion block
•
If initial measures fail: Exploration and attempt at reanastomosis
•
Late (>12 hours) replantation failure: Due to venous congestion or thrombosis
•
Diagnosis: Rubrous skin color, increased capillary refill, tissue engorgement
•
Arterial inflow may subsequently diminish.
•
Initial treatment: Removal of dressings and elevation of extremity
•
Heparin-soaked pledgets
•
Medicinal leeches (Hirudo medicinalis): Produce the anticoagulant hirudin, yield 8–12 hours of sustained bleeding (Fig. 7.45)
•
May be required for up to 5–7 days
•
Aeromonas hydrophila infection risk: Prophylactic antibiotics (e.g., ceftriaxone or ciprofloxacin) during leech therapy
•
Revision of venous anastomosis is last resort.
•
Late complications: Tendon adhesions, bone nonunion, and neuroma formation
•
Tenolysis is the most commonly performed secondary procedure following successful replantation.
•
Results
•
Factor most predictive of digit survival after replantation: Mechanism of injury (clean cut better than crush or avulsion)
•
Next most important factor: (Probably) ischemia time
•
Clean transverse amputations with cold ischemia time less than 8 hours survive replantation in more than 90% of cases
•
After 8 hours, the success rate drops to approximately 75%.
•
Replanted digits typically regain 50% of total active motion and static two-point discrimination of approximately 10 mm.
•
Long-term cold intolerance is almost universal, regardless of whether amputated digit is replanted or revised.
□
Forearm and arm replantation
•
Key Point: Arterial inflow is established before skeletal stabilization (with use of shunts if necessary) to minimize ischemia time.
•
Postreplantation fasciotomies performed to prevent reperfusion-induced compartment syndrome
•
Muscle necrosis leads to myoglobinuria and life-threatening renal failure.
•
Elevated postoperative serum potassium value may be prognostic of replantation failure.
•
Late complications: Infection, Volkmann ischemic contracture, insignificant functional recovery
□
Hand allotransplantation
•
Occurring around the world with more frequency, including in United States, at specialized centers with abundant resources
•
Bilateral transplantations have been performed with good survivorship, including several above-elbow procedures.
•
Newer immunosuppressive protocols are less toxic and may lead to less long-term recipient morbidity.
•
Long-term risk of continued immunosuppression is malignancy.
Replantation sequence of parts
Operative sequence of replantation (mnemonic: BEFAVNS)
•
Bone stabilization, usually with shortening
•
Extensor tendon repair
•
Flexor tendon(s) repair
•
Arterial reanastomosis
•
Venous reanastomosis
•
Nerve repair
•
Skin approximation (loose)
•
If multiple digits, priority sequence is thumb > long > ring > small > index
•
Thumb provides 40% of hand function.
•
Structure-by-structure technique faster and yields higher viability rate than finger-by-finger technique.
•
Use of venous couplers may result in shorter operative times and less vasospastic collapse of the anastomosis.
Thumb reconstriuction options
Traumatic thumb loss devastating to overall hand function (thumb accounts for 40% of hand function)
•
For amputation through middle to proximal third of proximal phalanx
•
First web space deepening
•
Metacarpal lengthening with dynamic distraction external fixator
•
Average 3-cm gain
•
For more proximal amputation level
•
Index finger pollicization
•
Great or second toe transfer by microvascular reconstruction
RIng Avulsion Injuries
Forceful avulsion of overlying soft tissues from skeletal structures
□
Classified by Urbaniak
•
Class I: Circulation adequate; digit salvage with standard soft tissue treatment
•
Class II: Circulation compromised and inadequate; revascularization recommended if no accompanying severe bone or tendon injury
•
Class III: Complete degloving; treated with completion amputation
Keinboch disease
Overview
•
Progressive, often debilitating disease
•
Characterized by fragmentation and collapse of lunate
•
Demographics: Men aged 20–40 years
•
Rare in children but they have a better prognosis
•
Rarely bilateral
•
Multifactorial etiology postulated
•
Lunate geometry
•
Anatomic variability of lunate blood supply
•
Single arterial supply; limited intraosseous branching most susceptible
•
Increased intraosseous pressure from venous stasis
•
Negative ulnar variance
•
Increased shear stress on marginally perfused lunate
•
Decreased radial inclination
□
Diagnosis
•
Dorsal wrist pain, mild swelling, limited motion, weakness
•
Ulnar variance determined with wrist posteroanterior in neutral rotation
•
Radiographic findings initially normal or show a linear fracture
•
Advanced stages: Lunate sclerosis followed by lunate collapse
•
Presentation: Unexplained persistent, non–activity-related dorsal wrist pain in young adult with negative ulnar variance should prompt MRI evaluation.
•
MRI (early diagnosis): Diffuse low signal intensity throughout lunate on T1- and T2-weighted images
Treatment
•
Based on Lichtman stage and ulnar variance
•
In general, goal in stages I–IIIA is to save the lunate; surgery in stages IIIB–IV, consists of salvage procedures because lunate pathology prevents its revascularization.
•
Stage I: Trial of cast immobilization, but long-term success is limited.
•
Stage II or higher: Surgical treatment according to MRI findings
•
First-line surgical treatment: Joint-leveling procedure
•
Ulnar-negative variance: Radial shortening osteotomy is preferred over ulnar lengthening with bone grafting (goal is neutral or 1-mm positive).
•
Ulnar-positive variance: Capitate shortening with capitohamate fusion.
•
Early stages: Core decompression of the radius and ulna is an option.
•
Thought to incite local vascular healing response
•
Vascularized bone grafting (stages I–IIIA)
•
Preferred pedicle is the fourth and fifth extracompartmental artery (4–5 ECA)
•
May be combined with scaphocapitate pinning and/or external fixation to “unload” the lunate temporarily
•
Other options: Pedicled vascularized transfers from pisiform and index metacarpal as well as free vascularized bone transfers
•
There is little evidence to support one procedure over another for the treatment of stages I–IIIA disease.
•
Treatment of stage IIIB disease must address the associated carpal instability.
•
Options: Scaphoid-trapezium-trapezoid fusion, scaphocapitate fusion, PRC
•
Stage IV disease (radiocarpal and/or midcarpal arthrosis): Either PRC or wrist fusion
Preiser’s Disease
Rare diagnosis based on radiographic evidence of sclerosis and fragmentation of the scaphoid without evidence of prior fracture
□
Predisposing vascular patterns have not been determined.
□
Demographics: Average age at onset is 45 years
□
Presentation: Insidious dorsoradial wrist pain
□
Classification: Four-stage radiographic classification similar to that for Kienböck disease
•
May also more simply be classified by MRI into complete and partial involvement
□
Initial treatment: Cast immobilization
□
Surgical treatment: Core decompression, curettage, allograft replacement, vascularized bone grafting with 1,2 ICSRA, PRC, scaphoid excision and four-corner fusion, or total wrist fusion
Review Hand Infections
Hand infections can involve any tissue type and a variety of pathogens (Table 7.13).
□
Staphylococcus aureus: Overall most common pathogen
□
Streptococcus second most common
□
Gram-negative and anaerobic bacteria are seen in intravenous drug abusers (IVDAs), diabetic patients, and in patients with farmyard injuries or bite wounds.
□
Community-acquired methicillin-resistant S. aureus (MRSA) is becoming more prevalent, especially in urban communities.
•
Risk factors: Antibiotic use in previous year, close and crowded living conditions, compromised skin integrity, sharing of items (towels, whirlpools, fitness equipment)
•
Risk groups: IVDAs, homeless people, children in daycare, prison inmates, military recruits, athletes in contact sports
•
High complication rate in diabetic patients
•
IV treatment with vancomycin or clindamycin; outpatient treatment with oral trimethoprim-sulfamethoxazole or clindamycin
▪
Paronychia/eponychia
□
Infections involving the nail fold are more common in the hand.
□
Typically S. aureus
□
Treatment: Incision and drainage, partial or total nail plate removal, oral antibiotics, soaks, and dressing changes
•
Eponychial fold (cuticle) must be preserved if possible.
□
Chronic paronychia unresponsive to oral antibiotic therapy often secondary to fungal infection (Candida albicans)
□
In rare cases, marsupialization (excision of the dorsal eponychium) may be required to eradicate the infection.
▪
Felon
□
Infection of the septated fingertip pulp
□
S. aureus is most common pathogen
□
Treatment: Incision and drainage through a central or midlateral incision
•
Septae must be broken up to adequately decompress the fingertip.
•
Midlateral digital incisions are usually placed ulnarly, except in the thumb and small digit, where they are placed radially (Fig. 7.74).
•
Incision should be left open to heal by second intention.
•
Delayed treatment: Concurrent flexor tenosynovitis, osteomyelitis, or digital tip necrosis
▪
Human bite
□
Potentially serious infection treated promptly with incision and drainage (I&D), especially if joint or tendon sheath is violated
□
Most commonly involves the third or fourth MCP joint (fight bite)
□
Most frequently isolated organisms: group A streptococci, S. aureus, Eikenella corrodens, and Bacteroides spp.
□
Antibiotics for empiric therapy: IV ampicillin/sulbactam and oral amoxicillin/clavulanate
▪
Dog and cat bites
□
More than 2 million cases per year in the United States
□
Vast majority are dog bites, with lower rate of serious infection.
•
More likely to avulse or crush soft tissue but often amenable to local wound care
□
Minority are cat bites, but they have a higher rate of serious infection.
•
Deeper penetrance, smaller wounds, and longer time to initiation of treatment
□
Nonoperative treatment: If patient presents immediately after bite
•
Splinting, elevation, soaks, and antibiotics, followed by aggressive therapy once infection controlled
□
Delayed treatment: Abscess formation and need for operative I&D
•
Further delay could lead to septic tenosynovitis, septic arthritis, and/or osteomyelitis
□
Antibiotics for empiric therapy: Ampicillin/sulbactam and amoxicillin/clavulanate
•
In patient with penicillin allergy: Ciprofloxacin, doxycycline, or tetracycline
•
Covers Pasteurella multocida (part of animal oral flora), S. aureus, and Streptococcus spp.
Review Flexor tenosynovitis
Infection of flexor tendon sheath
□
May occur in delayed fashion after penetrating trauma
□
S. aureus is most common pathogen
□
Kanavel signs (four)
•
Flexed resting posture of digit
•
Fusiform swelling of digit
•
Tenderness of flexor tendon sheath
•
Pain with passive digit extension
□
Early treatment: Hospital admission, splinting, IV antibiotics, and close observation
•
If signs improve within first 24 hours, surgery may be avoided.
□
Late treatment: Incision and drainage of flexor tendon sheath
•
Technique (Fig. 7.75)
•
Open drainage: Long midaxial or Bruner incision
•
Closed-catheter irrigation (CCI): Two small incisions placed distally (open A5 pulley) and proximally (open A1 pulley) with use of a pediatric feeding tube
•
Studies show similar outcomes for open and catheter irrigation techniques.
•
Classic horseshoe abscess: Proximal communication between the thumb and small finger flexor tendon sheaths in the Parona space (potential space between the PQ and FDP tendons)
•
Aggressive postoperative hand therapy is paramount because tendon adhesions and digital stiffness are likely.
Injection Injury
High-pressure injection injuries can be devastating.
▪
High rate of digital amputation
□
Organic solvents more toxic to tissue
□
Oil-based paint worse than latex or water-based
▪
Treatment: Emergent wide surgical débridement
Wrist Arthroscopy
Indicated for the diagnosis of wrist pain
□
Indications: TFCC tears, osteochondral injuries, loose bodies, intercarpal ligament injuries, ganglions, intraarticular distal radius fractures, and scaphoid fractures
□
Equipment: Traction tower, 1.9- or 2.7-mm, 30-degree arthroscope
□
Arthroscopic portals (Fig. 7.38)
□
Diagnostic arthroscopy: Radiocarpal → ulnocarpal → midcarpal joint inspection
□
Most common complication: Injury to superficial sensory nerves (branches of superficial sensory radial, dorsal sensory ulnar, lateral antebrachial cutaneous)
General Overview of Compression Neuropathies
What is the sequence of sensory loss?
light touch
pressure and vibration
pain and temperature
Review Parsonage-Turner syndrome
Parsonage-Turner syndrome
•
Characterized by viral illness and shoulder pain prior to nerve symptoms
•
Self-limiting inflammatory brachial neuritis or plexopathy
•
Diabetes, thyroid disease, inflammatory arthropathy, vitamin deficiency
□
Physical examination
•
Individual muscle strength (grades 0 [none] to 5 [maximal]), pinch strength, and grip strength in cases of long-standing compression
•
Neurosensory testing performed in context of both dermatomal and peripheral nerve distributions
•
Semmes-Weinstein monofilaments measure the cutaneous pressure threshold, a function of large nerve fibers (first to be affected in compression neuropathy).
•
Sensing the 2.83 monofilament is normal.
•
Two-point discrimination (performed with patient’s eyes closed)
•
Inability to perceive a difference between points more than 6 mm apart is considered abnormal and constitutes a late finding in compression neuropathy.
Review double crush syndrome
Double-crush phenomenon
•
Normal axonal function depends on factors synthesized in the nerve cell body.
•
Blockage of axonal transport at one point makes the entire axon more susceptible to compression elsewhere.
•
Cervical radiculopathy or proximal nerve entrapment may coexist with distal nerve compression in double-crush phenomenon.
•
Outcome of surgical decompression may be disappointing unless all points of compression are addressed.
•
Logical approach is to start with less complex distal releases.
Composite image of peripheral nerve compression
Composite figure showing multiple types of nerve compression syndromes. The radial nerve is involved in posterior interosseous nerve (PIN), radial tunnel, and Wartenberg syndromes. The median nerve is involved in the pronator, anterior interosseous nerve (AIN), and carpal tunnel syndromes. The ulnar nerve is involved in the cubital tunnel and Guyon canal syndromes. Various points of compression and associated anatomy are illustrated in the figure.
Review Carpal Tunnel Syndrome
Most common compressive neuropathy in the upper extremity
•
≈500,000 cases per year in United States
•
Anatomy of the carpal tunnel
•
Volar boundary (roof): Transverse carpal ligament (TCL)
•
Attaches to scaphoid tubercle/trapezium radially and to pisiform/hook of hamate ulnarly
•
Dorsal boundary (floor): Proximal carpal row and extrinsic volar carpal ligaments
•
Contents: Median nerve, FPL, four FDS tendons, and four FDP tendons
•
Normal pressure ≈2.5 mm Hg
•
Pressure more than 20 mm Hg: Epineural blood flow decreases; nerve becomes edematous.
•
Pressure more than 30 mm Hg: Nerve conduction decreases.
•
Forms of CTS
•
Idiopathic form; most common in adults
•
Mucopolysaccharidosis is the most common cause in children
•
May also be anatomic variation
•
Persistent median artery, small carpal canal, anomalous muscles, extrinsic mass effect
•
Risk factors: obesity, pregnancy, diabetes, thyroid disease, chronic renal failure, inflammatory arthropathy, storage diseases, vitamin deficiency, alcoholism, advanced age, vibratory exposure at work
•
Direct relationship between repetitive work activities (e.g., keyboarding) and CTS has never been established.
•
Acute CTS occurs in the setting of high-energy trauma (e.g., perilunate dislocation, hemorrhage, infection).
•
Evolving paresthesias and pain with increasing intensity
•
Treatment: Emergent decompression
•
Diagnosis (clinical)
•
Presentation: Paresthesias and pain (often at night) in volar aspect of radial 3½ digits (thumb, index, long, and radial half of ring)
•
Late findings: Weakness, loss of fine motor control, abnormal two-point discrimination
•
Most sensitive provocative test: Carpal tunnel compression test (Durkan test) with wrist in neutral position
•
Other provocative tests: Tinel test over the median nerve; Phalen test produces symptoms with wrist flexion.
•
Large sensory fibers (light touch, vibration) are affected before small fibers (pain and temperature).
•
Semmes-Weinstein monofilament testing is sensitive for diagnosing early CTS
•
Thenar atrophy may be present in severe denervation
•
CTS-6 diagnostic tool (Graham, 2008)
•
There is an 80% probability of CTS if patient has all 6 features:
•
Symptoms along digits innervated by median nerve
•
Night-time symptoms
•
Thenar atrophy or weakness
•
Presence of Tinel sign over median nerve
•
Positive Phalen test result
•
Loss of two-point discrimination
•
Electrodiagnostic tests are not necessary for the diagnosis of CTS but may help confirm diagnosis in equivocal cases
•
Distal sensory latencies of more than 3.5 ms or motor latencies of more than 4.5 ms are abnormal.
•
Decreased conduction velocity and decreased peak amplitude are less specific.
•
EMG may show increased insertional activity, positive sharp waves, fibrillation, and/or abductor pollicis brevis fasciculation.
•
More severe findings on EMG are associated with worse treatment outcomes.
•
Differential diagnosis: cervical radiculopathy, brachial plexopathy, thoracic outlet syndrome, pronator syndrome, ulnar neuropathy with Martin-Gruber anastomoses, peripheral neuropathy
•
Treatment
•
Nonoperative treatment: activity modification, night splints to keep wrist in neutral extension and decrease pressure within carpal tunnel, NSAIDs
•
Single corticosteroid injection yields transient relief in approximately 80% of patients after 6 weeks, but only 20% are symptom free by 1 year.
•
Failure to improve after corticosteroid injection is poor prognostic sign; surgery less successful in these cases.
•
Surgical treatment: open, mini-open, or endoscopic release of the TCL
•
No additional benefit gained from internal median nerve neurolysis or flexor tenosynovectomy
•
No need for preoperative antibiotics
•
Nerves at risk
•
If incision and approach are too ulnar: Ulnar neurovascular structures within Guyon canal
•
If incision and approach are too radial: Recurrent motor branch of the median nerve (Fig. 7.50)
•
Three main variations of the recurrent motor branch
•
Extraligamentous—approximately 50%
•
Subligamentous—approximately 30%
•
Transligamentous—approximately 20%
•
Endoscopic carpal tunnel release: Outcomes similar to those of open release, with potentially less early scar tenderness, better short-term grip/pinch strength, and shorter return to work
•
Long-term outcomes of endoscopic and open release procedures are equivalent
•
Endoscopic release is associated with a surgeon learning curve; higher rate of major complications (nerve injury or incomplete TCL division) may be seen early in surgeon experience.
•
Open carpal tunnel release
•
Pinch strength returns to preoperative level in 6 weeks, and grip strength in 3 months.
•
Pillar pain adjacent to incision for 3–4 months after open carpal tunnel release is common.
•
Persistent symptoms after release: May be secondary to incomplete release of the TCL, a missed double-crush phenomenon, concomitant peripheral neuropathy, space-occupying lesion, or wrong diagnosis
•
Worsening symptoms after surgery may indicate iatrogenic nerve injury.
•
Higher severity of preoperative symptoms negatively impacts the degree of symptom relief after carpal tunnel release.
•
Depression and poor coping mechanisms shown to predict patient dissatisfaction
•
Pain catastrophizing also prolongs return to work.
•
Chronic compression in elderly patients
•
Full sensory and motor function rarely recovered
•
Relief of painful nocturnal paresthesias more consistent
•
Improvements in activities of daily living, work performance, and overall hand function
•
Over 90% of patients satisfied with outcome
•
Revision carpal tunnel release: Outcome depends on identification and treatment of the underlying cause of the failure.
•
Hypothenar or fat pad graft may be employed in revision cases (pedicle off ulnar artery).
Review Pronator Syndrome
SLAPS
Compression of the median nerve in the arm/forearm
•
Potential sites of compression (Fig. 7.51) (mnemonic: SLAPS [©Kakar])
•
Supracondylar process: Anterior distal humerus seen on lateral radiograph, in ∼1% of the population
•
Ligament of Struthers: Courses between the supracondylar process and medial epicondyle
•
Bicipital aponeurosis (lacertus fibrosis)
•
FDS aponeurotic arch
•
Between the two heads of pronator teres muscle
•
Pronator syndrome differentiated from CTS by proximal volar forearm pain and sensory disturbances in distribution of palmar cutaneous branch of the median nerve over the thenar region, which comes off the median nerve proximal to the carpal tunnel
•
Patients with CTS have normal sensation over the thenar eminence
•
Patients with pronator syndrome have decreased sensation over the thenar region
•
Provocative tests: Resisted elbow flexion with forearm supinated (bicipital aponeurosis), resisted forearm pronation with elbow extended (pronator teres), and resisted long finger PIP joint flexion (FDS)
•
Electrodiagnostic test results often inconclusive
•
Nonoperative treatment: Activity modification, splints, NSAIDs
•
Surgical treatment (with failure of nonoperative management): Release of all potential sites of compression
•
Success rate approximately 80% in most series
•
Pronator syndrome is often associated with medial epicondylitis and tends to improve with its treatment
AIN syndrome
Hand OK sign failure
Involves motor loss of FPL, index ± long FDP, and PQ
•
No sensory disturbance
•
Precision sign: Index FDP and thumb FPL tested by asking patient to make an “OK” sign
•
Provocative test: PQ involvement tested by resisted pronation with elbow maximally flexed
•
Differential diagnosis
•
Transient AIN palsy is associated with Parsonage-Turner syndrome (viral brachial neuritis), especially if motor loss was preceded by intense shoulder pain or viral illness.
•
Isolated tendon rupture (e.g., Mannerfelt syndrome in RA with isolated FPL rupture as the tendon runs over the carpus within the wrist) must be ruled out.
•
EMG may help confirm diagnosis.
•
Sites/causes of median nerve compression in AIN syndrome, in addition to those listed for pronator syndrome, include
•
Enlarged bicipital bursa at the elbow
•
Gantzer muscle (accessory head of the FPL)
•
Vast majority of patients recover with observation
•
Nonoperative treatment: Activity modification and elbow splinting in 90 degrees of flexion
•
Results of surgical decompression generally satisfactory if done within 3–6 months after onset of symptoms
Ulnar Nerve Entrapment:
Cubital Tunnel Syndrome
Sites of ulnar entrapment. The nerve may be entrapped by (1) the arcade of Struthers, (2) the medial intermuscular septum, (3) the distal transverse fibers of the arcade of Struthers, (4) the Osborne ligament, and/or (5) the fascia (aponeurosis) of the FCU and fascial bands within the FCU.
Second most common compression neuropathy of upper extremity
•
Definition of the cubital tunnel
•
Deep (floor): medial collateral ligament (MCL) and elbow joint capsule
•
Walls of the tunnel: medial epicondyle and olecranon
•
Roof: FCU fascia and arcuate ligament of Osborne (fibrous band that traverses cubital tunnel from medial epicondyle to olecranon)
•
Sites of compression (Fig. 7.52) (mnemonic: AO TEAM [©Kakar])
•
Arcade of Struthers: fascial thickening at hiatus of medial intermuscular septum as the ulnar nerve passes from anterior to posterior compartment
•
Location: ≈8 cm proximal to the medial epicondyle
•
Osborne ligament
•
Medial head of triceps
•
Anconeus epitrochlearis: Anomalous muscle originating from medial olecranon and inserting on medial epicondyle
•
Aponeurosis of proximal edge of FDS or two heads of FCU
•
Medial intermuscular septum
•
External sources of compression: Tumors, ganglions, osteophytes, heterotopic ossification (HO), medial epicondyle nonunion
•
Other associations: Burns, cubitus valgus deformities, medial epicondylitis, and repetitive elbow flexion/valgus stress during occupational or athletic activities
•
Differential diagnosis: Special awareness of thoracic outlet syndrome and cervical radiculopathy (C8–T1)
•
Presentation: Paresthesias of the ulnar 1½ digits (ulnar half of ring and small) and dorsal ulnar hand
•
Provocative tests: Direct cubital tunnel compression, Tinel test, and prolonged elbow hyperflexion
•
Examiner should check for subluxation of ulnar nerve over medial epicondyle during elbow flexion-extension arc
•
Classic examination findings secondary to motor weakness
•
Froment sign
•
Compensatory thumb IP joint flexion (FPL) during key pinch due to weak adductor pollicis
•
Jeanne sign
•
Hyperextension of thumb MCP with key pinch due to weak adductor pollicis
•
Wartenberg sign
•
Persistent abduction and extension of small digit during attempted adduction due to weak third volar interosseous and small finger lumbrical
•
Masse sign
•
Flattening of palmar arch and loss of ulnar hand elevation due to weak opponens digiti quinti and decreased small digit MCP flexion
•
Interosseous and/or first web space atrophy
•
Ring and small digit clawing due to FDP contraction and paralysis of the intrinsic muscles
•
Electrodiagnostic tests are helpful for diagnosis and prognosis
•
Conduction velocity of less than 50 m/sec across elbow is the typical threshold for diagnosis; larger decreases in conduction velocity signal worse disease.
•
Nonoperative treatment: Activity modification, night splints (elbow held in relative extension), FCU stretching, NSAIDs
•
Numerous surgical techniques described
•
In situ decompression
•
Anterior transposition
•
Subcutaneous
•
Submuscular
•
Intramuscular
•
Medial epicondylectomy
•
Newer meta-analyses of techniques did not show statistically significant difference in outcomes between simple decompression and transposition when there is no ulnar nerve instability
•
Higher rate of recurrence than after carpal tunnel release
•
Better outcomes if release performed before motor symptoms appear
•
Promising early outcomes, but no long-term studies for endoscopic techniques
•
Persistent postoperative medial/posterior elbow pain: Neuroma formation from iatrogenic injury to branches of the medial antebrachial cutaneous nerve should be considered as possible cause.
Ulnar Tunnel Syndrome:
Compression neuropathy of ulnar nerve in Guyon canal
•
Most common cause: Ganglion cyst (80% of nontraumatic cases)
•
Other causative factors: hook of hamate nonunion, ulnar artery thrombosis, lipoma, palmaris brevis hypertrophy, other anomalous muscle
•
Borders of the Guyon canal: volar carpal ligament (roof), TCL (floor), hook of hamate (radial), and pisiform and ADM muscle belly (ulnar)
•
Ulnar tunnel divided into three zones
•
Zone I: Proximal to bifurcation of ulnar nerve; associated with mixed motor/sensory symptoms
•
Zone II: Deep motor branch; associated with pure motor symptoms
•
Zone III: Distal sensory branches; associated with pure sensory symptoms
•
Useful adjunctive tests include
•
CT: Hamate hook fracture
•
MRI: Ganglion cyst or other space-occupying lesion
•
Doppler ultrasonography: Ulnar artery thrombosis
•
Success of treatment depends on identifying the cause
•
Nonoperative treatment: Activity modification, splints, NSAIDs
•
Surgical treatment: Decompression followed by addressing of underlying cause
•
Concurrent CTS: Guyon canal is adequately decompressed by release of the transverse carpal ligament.
PIN Syndrome
LEAFS
Presentation: Lateral elbow pain and distal muscle weakness
•
Radial deviation occurs with active wrist extension, because ECRL is innervated by radial nerve proper more proximally.
•
PIN innervates the ECRB, supinator, EIP, ECU, extensor digitorum communis (EDC), extensor digiti minimi (EDM), APL, EPB, and EPL
•
First muscle innervated is the brachioradialis
•
Last muscle innervated (and last to recover after injury) is the EIP
•
Patients may also have dorsal wrist pain where the terminal nerve fibers provide sensory innervation to the dorsal wrist capsule
•
Terminal branch is located on the floor of the fourth extensor compartment
•
EMG helps confirm diagnosis
•
Anatomic sites of compression include (Fig. 7.53) (mnemonic: LEAFS [©Kakar])
•
Recurrent leash of Henry
•
Edge of the ECRB
•
Arcade of Frohse (most common site, at proximal edge of supinator) and fascial band at the radial head
•
Distal edge of the supinator
•
Unusual causes include chronic radial head dislocation, Monteggia fracture-dislocation, radiocapitellar rheumatoid synovitis, and space-occupying elbow mass (e.g., lipoma)
•
PIN palsy is differentiated from extensor tendon rupture by a normal wrist tenodesis test result
•
Nonoperative treatment: Activity modification, splinting, NSAIDs
•
Surgical treatment (if no recovery by 3 months): Surgical decompression of anatomic sites of compression provides good to excellent results for 85% of patients
Radial Tunnel Syndrome and Wartenbergs Syndrome
Radial tunnel syndrome (see Fig. 7.49)
•
Presentation: Lateral elbow/radial forearm pain without motor or sensory dysfunction
•
The point of maximum tenderness is several centimeters distal to lateral epicondyle.
•
Provocative tests include resisted long-finger extension (positive result: resistance reproduces pain at the radial tunnel) and resisted supination.
•
Lateral epicondylitis coexists in a small percentage of patients.
•
Electrodiagnostic test results are typically inconclusive
•
Nonoperative treatment: Prolonged (up to 1 year); activity modification, splints, NSAIDs, other modalities
•
Surgical decompression: Results less predictable than for PIN syndrome; good to excellent results in only 50%–80% of cases after prolonged postoperative recovery
□
Cheiralgia paresthetica (Wartenberg syndrome) (see Fig. 7.49)
•
Compressive neuropathy of SBRN
•
Nerve is compressed between brachioradialis and ECRL with forearm pronation (by a scissor-like action between the tendons).
•
Presentation: Pain, numbness, and paresthesias over the dorsoradial hand, inability to wear a watch or jewelry secondary to pain over the nerve
•
Provocative tests: Forceful forearm pronation for 60 seconds, Tinel test
•
Nonoperative treatment: Activity modification, splinting, NSAIDs
•
Surgical decompression: Warranted if 6-month trial of nonoperative treatment fails
Classification of Nerve Injuries
Neurapraxia
•
Injury type: Mild nerve stretch or contusion
•
Focal conduction block
•
No wallerian degeneration
•
Disruption of myelin sheath
•
Epineurium, perineurium, endoneurium intact
•
Prognosis: Excellent; recovery expected
•
Axonotmesis
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Injury type: Incomplete nerve injury
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Focal conduction block
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Wallerian degeneration distal to injury
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Disruption of axons
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Sequential loss of axon, endoneurium, perineurium (Sunderland classes 2, 3, 4)
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Neuroma-in-continuity may develop
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Prognosis: Recovery unpredictable
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Neurotmesis
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Injury type: Complete nerve injury
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Focal conduction block
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Wallerian degeneration distal to injury
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Disruption of all layers, including epineurium
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Neuroma formation by proximal nerve end
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Glioma formation by distal end
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Prognosis: Worst recovery
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In axonotmesis and neurotmesis, the distal nerve segment undergoes wallerian degeneration.
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The degradation products are removed by phagocytosis.
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Myelin-producing Schwann cells proliferate and align themselves along the basement membrane, forming a tube that will receive regenerating axons.
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Nerve cell body enlarges as rate of structural protein production increases.
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Each proximal axon forms multiple sprouts that connect to the distal stump and migrate at a rate of 1 mm/day.
anatomy of a nerve sheath
Nerve structure epineural sheath
surrounds peripheral nerve
epineurium
surrounds a group of fascicles to form peripheral nerve
functions to cushion fascicles against external pressure
perineurium
connective tissue covering individual fascicles
primary source of tensile strength and elasticity of a peripheral nerve
provides extension of the blood-brain barrier
provides a connective tissue sheath around each nerve fascicle
fascicles
a group of axons and surrounding endoneurium
endoneurium
loose fibrous tissue covering axons
participates in the formation of Schwann cell tube
myelin
made by Schwann cells
insulates axons to increase conduction velocity
conduction occurs at nodes of Ranvier
neuron cell
cell body - the metabolic center that makes up < 10% of cell mass
axon - primary conducting vehicle
dendrites - thin branching processes that receive input from surrounding nerve cells
Nerve fiber types
Fingertip flap options
