Upper Extremity Flashcards
Division of axial load (%) supported by the distal radius and ulna/triangular fibrocartilage complex:
80% axial load by distal radius, 20% ulna/tfcc
Reversal of the normal palmar/voler tilt results in what in regards to axial load?
Reversal of the normal palmar tilt results in load transfer onto the ulna and TFCC. The remaining load is then borne eccentrically by the distal radius and is concentrated on the dorsal aspect of the scaphoid fossa
Which set of ligaments confer more stability to the radiocarpal articulation?
The volar ligaments are stronger and confer more stability than the dorsal ligaments
Most common mechanism of injury for distal radius fxs?
Fall onto an outstretched hand with the wrist in dorsiflexion
The radius initially fails in tension on the volar aspect, with the fx propagating _________.
Dorsally
Bending moment forces of the distal radius induce compression stresses resulting in _____ __________.
Dorsal comminution
Radiographic eval for distal radius
PA, lateral, oblique for further definition
Normal Radiographic relationship for radial inclination:
23 degrees (13-30)
Normal Radiographic relationship for radial length
11mm (8-18mm)
Normal radiographic relationship for Palmar (volar) tilt
Averages 11-12 degrees (range from 0 to 28)
Classification system for Colles fx based on intraarticular involvement
Frykman
Frykman classification system:
Extra-articular = type 1, + distal ulna fx = type 2
Intra-articular involving radiocarpal joint = type 3, + distal ulna fx = type 4
Intra-articular involving distal radioulnar joint (DRUJ) = type 5, + distal ulna fx = type 6
Intra-articular involving radiocarpal and DRUJ = type 7, + distal ulna fx = type 8
Mechanism based classification system for distal radius fx
Fernandez classification
Fernandez classification:
Type 1: metaphyseal bending fx with the inherent problems or loss of palmar tilt and radial shortening relative to ulna (DRUJ injury)
Type 2: shearing fx requiring reduction and often buttressing of the articular segment
Type 3: compression of the articular surface WITHOUT THE CHARACTERISTIC FRAGMENTATION; also the potential for significant interosseous ligament injury
Type 4: avulsion fx or radiocarpal fx-dislocation
Type 5: combined injury with significant soft tissue involvement owing to high energy injury
Extra-articular (original description) and intra-articular distal radius fx demonstrating various combinations of dorsal angulation (apex volar), dorsal displacement, radial shift, and radial shortening:
Colles fx
Exact mechanism of injury for Colles fx
Fall on hyperextended, radially deviated wrist with the forearm in pronation
Fx with volar angulation (apex dorsal) of the distal radius with a “garden spade” deformity or volar displacement of the hand and distal radius
Smith fx (reverse Colles)
Mechanism of injury for smith fx:
Fall onto flexed wrist with the forearm fixed in supination…produces unstable fx pattern
Shearing mechanism of injury that results in a fx-dislocation or subluxation of the wrist in which the dorsal or volar rim of the distal radius is displaced with the hand and carpus
Barton fx
Mechanism of injury for Barton fx
Fall onto a dorsiflexed wrist with the forearm fixed in pronation
An avulsion fx with extrinsic ligaments remaining attached to the styloid fragment
Radial styloid fx = chauffer’s fx, backfire fx, Hutchinson fx
Mechanism of injury for chauffeur fx
Compression of the scaphoid against the styloid with the wrist in dorsiflexion and ulnar deviation
Radiographic alignment parameters for acceptable reduction in an active, healthy pt
Radial length: within 2 to 3 mm of the contralateral side
Palmar tilt: neutral tilt, but up to 10 degrees dorsal angulation
Intra-articular step off less than two mm
Radial inclination less than five degree loss
How is carpal alignment measured on a lateral radiograph
By the intersection of 2 lines: one parallel and through the middle of the radial shaft and the other through and parallel to the capitate. If the two lines intersect within the carpus, then the carpus is aligned.
Factors associated with redisplacement following closed manipulation of a distal radius fx
1: the initial displacement of the fracture
2: the age of the patient
3: extent of metaphyseal comminution
4: displacement following closed reduction
Primary Nonoperative tx for distal radius fx
Closed reduction: accentuate, traction, opposite. Long arm “sugar tong” splint with the wrist in neutral or slight flexion. Leave the MCP joints free. 6 weeks or until Radiographic evidence of union
Primary operative tx for extra-articular fractures or 2 part intra-articular fxs of distal radius
Percutaneous pinning: 2 or 3 kirschner wires placed across the fx site, generally from the radial styloid directed proximally and from the dorsoulnar side of the distal radial fragment directed proximally
Technique of trapping the distal fragment by buttressing to prevent displacement by inserting wires radially and dorsally directly into the fx site, then levering up and directing into the fx site
Kapandji “intrafocal” pinning
Options for ORIF of distal radius
1: dorsal plating - fixation is on the compression side, avoids neurovascular structures on palmar side, associated with extensor tendon complications
2: volar nonlocked plating - primary indication is a buttress plate for the shear fx of the volar Barton
3: volar locked plating - stabilizes distal radius fxs with dorsal comminution
Position of the proximal humerus relative to the epicondylar axis
35-40 degrees retroverted
4 osseous segments of the humerus (Neer)
Humeral head, greater tuberosity, lesser tuberosity, humeral shaft
Deforming muscular forces on the osseous segments:
The greater tuberosity is displaced superiority and posteriorly by the supraspinatous and external rotators
The lesser tuberosity is displaced medially by the pull of subscapularis
The humeral shaft is displaced medially by pec major
Proximal segment abducted by deltoid insertion
Major blood supply to the proximal humerus
Anterior and posterior humeral circumflex arteries. Humeral head supplied by arcuate artery (continuation of the ascending branch of the anterior humeral circumflex
Nerve that you must watch out for in proximal humerus fxs 2/2 it’s course just anteroinferior to the glenohumeral joint
Axillary nerve
Most commonly used surgical approach for the proximal humerus
Deltopectoral
Classification system used for proximal humerus fractures
Neer
Neer classification of proximal humerus fxs
Four parts: greater and lesser tuberosities, humeral shaft, humeral head.
A part is defined as displaced if: >1 cm of fracture displacement or >45 degrees of angulation
Fracture types include:
One part fxs - no displaced fragments regardless of the number of fx lines
Two part fx - any displaced piece (anatomic neck, surgical neck, greater tube, lesser tube
Three part fx - surgical neck with greater tube, surgical neck with lesser tube
Others: four part, fx dislocation, articular surface fx
Tx of minimally displaced fractures (one part)
Sling immobilization or swathe for comfort. Pendulum exercises, passive range of motion exercises, then active ROM exercises at 6 weeks
Treatment of two part anatomic neck fx
ORIF or prosthesis (elderly). High incidence of osteonecrosis
Tx of two part surgical neck fx
If fx is reducible and good bone quality, can consider fixation with Percutaneous pins or cannulated screws
Tx for Two part greater tuberosity fx
If displaced more than 5 to 10 mm (5 for superior translation), require ORIF with or without RCR
Tx of two part lesser tube fx
Tx closed unless inhibiting internal rotation
Tx of three part prox humerus fxs
Unstable 2/2 opposing muscle forces, ORIF or hemi
Tx of four part proximal humerus fxs
ORIF with locking plate and screw fixation, suture, and/or wire fixation
Recommended tx for anatomic neck fx-dislocations
Hemi arthroplasty - high incidence of osteonecrosis. These injuries may be associated with a higher incidence of myositis ossificans with repeated attempts at closed reduction
Percentage breakdown of humeral shaft fxs
60% middle third of diaphysis, 30% proximal third of diaphysis, 10% distal third of diaphysis
Vascular supply to the humeral diaphysis
Arises from perforating branches of the brachial artery, with the main nutrient artery entering the medial humerus distal to the midshaft
Mechanism of injury to humeral shaft resulting in comminuted or transverse fx
Direct (most common mechanism overall)
Mechanism of injury resulting in spiral or oblique midshaft humerus fxs
Indirect: fall on outstretched arm or rotational injury
Type of force applied to produce the following fxs:
1: proximal or distal humeral fxs
2: transverse shaft
3: spiral shaft
4: oblique, often with butterfly fragment
1: compressive
2: bending
3: torsional
4: torsional and bending
Descriptive classification of humeral shaft fxs
1: open vs closed
2: location - prox, mid, distal third
3: degree - displaced vs nondisplaced
4: direction and character - transverse, oblique, spiral, segmental, comminuted
5: intrinsic condition of bone
6: articular extension
Percent of humeral shaft fxs that will heal with nonsurgical tx
90%
Acceptable anterior angulation, varus angulation, and bayonet apposition that will not compromise function or appearance
20 degrees anterior angulation, 30 degrees varus angulation. 3 cm of bayonet appearance
Indication for hanging cast nonoperative tx
displaced midshaft humeral fx with shortening, particularly spiral or oblique patterns
Relative contraindications for hanging cast nonop tx
Short oblique or transverse
Acute tx of humeral shaft fxs with minimal shortening, short oblique or transverse fxs that may displace with hanging cast
Coaptation splint
Tx for minimally displaced or nondisplaced fxs that do not require reduction (shoulder/humerus)
Thoracobrachial immobilization (Velpeau dressing)
Nonoperative tx indicated when the fx pattern necessitates significant abduction and external rotation of the UE (operative tx is usually performed for these indications)
Shoulder spica cast
Preferred surgical approach for proximal third midshaft humeral fxs and the interval used. What nerve is identified between this interval?
Anterolateral, interval is between brachialis and brachioradialis. Radial nerve must be identified.
Muscular interval of the anterior and posterior surgical approaches to midshaft humerus
Anterior: muscular interval between biceps and brachialis
Posterior: interval between the lateral and long heads of triceps. Medial head is split. Must ID radial nerve in spiral groove
Surgical technique associated with the best functional results (does not violate the rotator cuff) and implant and fixation used
Open reduction and plate fixation with a 4.5 mm dynamic compression plate with 6-8 cortices of fixation proximal and distal to the fx. Lag screws used whenever possible
Indications for IM nailing the humerus (3)
1: segmental fxs in which plate placement would require significant soft tissue dissection
2: extremely osteopenic bone
3: pathologic fxs
2 types of IM nails and rationale for use of both in the humerus
1: flexible - fill the canal with multiple nails to achieve an interference fit. Use should be reserved for transverse or minimal comminution
2: interlocked - proximal and distal interlocking nails to provide rotational and axial stability.
With antegrade nailing, what is at risk for injury while inserting the proximal locking screw?
Axillary nerve
Distal locking of the humerus usually consists of a single screw in the AP plane. Why are these screws not inserted lateral to medial
Lateral to medial screws risk injury to the lateral antebrachial cutaneous nerve and the radial nerve
The proximal aspect of an IM humerus nail should be countersunk to prevent what?
Subacromial impingement
3 indications for external fixation of the humerus
1: infected nonunions
2: burn pts with fxs
3: open fx with extensive soft tissue loss
Most common (overall uncommon) vascular injury in humerus fx? Locations? Amount of time preferred to reestablish arterial inflow?
Brachial artery at proximal and distal third. 6 hours
Most common fx pattern of distal humerus fxs
Intercondylar
The joint surface to shaft axis, or the trochlear axis compared with the longitudinal axis is how many degrees
4-8 degrees of valgus
Rotation of the trochlear axis
3-8 degrees externally rotated
The IM canal ends approximately where in the humerus?
2-3 cm above the olecranon fossa
In nondisplaced fxs, an anterior or posterior “fat pad sign” may be present on the lateral radiograph, representing displacement of the adipose layer overlying the joint capsule in the presence of what?
Effusion or hemarthrosis
Normal condylar shaft angle on lateral xray
40 degrees
Operative tx for extra-articular supracondylar fxs
ORIF with plate fixation used on each column, either in parallel, 90 degrees or 180 degrees from one another
Operative tx for transcondylar fxs of the distal humerus
Open reduction and plate fixation, usually with precontoured locking plates
Mechanism of injury of most intercondylar fxs
Force is directed against the posterior aspect of an elbow flexed >90 degrees, thus driving the ulna into the trochlea
Classification system for intercondylar humeras fxs
Riseborough and Radin
Riseborough and Radin classification system
Type 1: nondisplaced condylar fx
Type 2: slight displacement with no rotation between the condylar fragments (T-condylar fx)
Type 3: displacement with rotation (T-condylar fx)
Type 4: severe comminution of the articular surface
Indications and types of nonoperative tx for intercondylar fxs
Nondisplaced, severe osteopenia and comminution, comorbid conditions. Cast immobilization (worst possible tx option-poor reduction and prolonged immobilization) or "bag of bones" to produce pseudoarthrosis
Operative txs and indications for intercondylar fxs
ORIF- displaced reconstructive fx, use interfrag screw or dual plate fixation
Total elbow arthroplasty - markedly comminuted or osteoporotic bone
Possible surgical approaches for intercondylar fx repair
1: tongue of triceps (Campbell’s)
2: olecranon osteotomy
3: triceps sparing extensive posterior approach (Bryan and Morrey)
Mechanism of injury for most condylar fxs
Abduction or adduction with the elbow in extension
2 classification systems used for condylar fxs
Milch and Jupiter
Milch classification system
Key is lateral trochlear ridge:
Type 1: lateral trochlear ridge is left intact
Type 2: lateral trochlear ridge is part of the condylar fragment
Nonoperative tx for condylar fxs (non or minimally displaced)
Posterior splinting with the elbow flexed to 90 degrees and the forearm in supination for lateral condylar fxs or pronation for medial condylar fxs
Operative tx of condylar fxs
Screw fixation with or without collateral ligament repair
Capitellum fx classification
Type 1: Hahn-steinthal fragment- large osseous component of capitellum, sometimes with trochlear involvement
Type 2: Kocher-Lorenz fragment - articular cartilage with minimal subchondral bone attached, “uncapping of the condyle”
Type 3: markedly comminuted (Morrey)
Type 4: extension into the trochlea (McKee)
Nonop tx for capitellum fxs
For nondisplaced fxs - posterior splint for 3 weeks followed by ROM exercises
Indication for operative tx and tx method for capitellum fxs
Indicated for type 1 displaced fxs via a posterolateral or posterior approach. ORIF
Mechanism of injury for trochlea fxs (laugier’s fxs)? Nonop and op tx?
Mechanism: tangential shearing force resulting from elbow dislocation
Nondisplaced fxs get posterior splint for 3 weeks
Displaced get kirschner wires or screw fixation
Operative indications for medial epicondyle fxs (4) with ORIF vs excision
1: displaced fragments with ulnar nerve symptoms
2: elbow instability to valgus stress
3: wrist flexor weakness
4: symptomatic nonunion of the displaced fragment
Name for the fibrous arch connecting the supracondylar process with the medial epicondyle, and the structures that pass through this arch
Ligament of Struthers
Median nerve and brachial artery
Provides valgus stability to the elbow? The anterior bundle is the primary stabilizer in what directions
Medial collateral ligament
Flexion and extension
Structures that provide varus stability to the elbow joint
Static: lateral collateral ligament
Dynamic: anconeous muscle
The capsuloligamentous structures of the elbow are injured in what direction of progression during dislocation of the elbow
Lateral to medial (Hori circle)
Structures that usually require repair following dislocation of the elbow. Structure that doesn’t require repair and why
Trochlear notch, radial head, lateral collateral ligament.
MCL: will usually heal properly with active motion, repair not necessary for stability
Classification of elbow dislocation (2, not specific names)
Simple vs complex (associated with fx)
According to the direction of the ulna in relation to the humerus: posterior, posterolateral, posteromedial, lateral, medial, anterior
Fx classification name and system used for fx-dislocations of the coronoid process
Regan and Morrey - based on size of fx fragment
Type 1: avulsion of the tip of the coronoid process
Type 2: a single or comminuted fragment involving 50% or less of the coronoid process
Type 3: single or comminuted fragment involving >50% of the coronoid process
Terrible triad of elbow injuries
Posterior dislocation with fxs of the radial head and coronoid process
Most common vascular structure injured in elbow dislocations
Brachial artery
Mechanism of injury and predictable fx pattern associated with each (2) for olecranon fxs
Direct: fall on point or direct trauma results in comminuted olecranon fx (less common)
Indirect: strong, sudden eccentric contraction of the triceps upon a flexed elbow typically results in a transverse or oblique fx
Classification name for olecranon fxs and 3 factors taken into consideration
Mayo classification
1: fx displacement
2: comminution
3: ulnohumeral stability
Mayo classification of olecranon fxs
Type 1: nondisplaced or minimally displaced; 1A is noncomminuted, 1B is comminuted. Tx is nonoperative
Type 2: displacement of the proximal fragment without elbow instability. Require operative tx. 2A are noncomminuted, tx by tension band wire fixation. 2B are comminuted and may require plate fixation
Type 3: instability of the ulnohumeral joint. Require surgery
Fx classification of olecranon fxs based on fx pattern
Schatzker: transverse, transverse-impacted, oblique, comminuted, oblique-distal, fx-dislocation
Nonoperative tx for olecranon fxs (reserved for nondisplaced mainly)
Immobilization in long arm cast or splint with elbow in 45-90 degrees flexion. May consider posterior splint
Operative indications for olecranon fx (2), tx of choice, and other tx options
1: disruption of the extensor mechanism (any displaced fx)
2: articular incongruity.
TOC = tension band wiring in combo with 2 parallel kirschner wires. Indicated for avulsion type fxs.
Other: IM fixation: 6.5 mm cancellous lag screw fixation. Plate and screw fixation. Excision
Tenderness to palpation or stress at the distal radioulnar joint, in association with a radial head fx, may indicate the presence of what lesion?
Essex-lopresti: radial head fx-dislocation with associated interosseous ligament and DRUJ disruption
Radiographic eval for radial head fxs
AP, lateral, and oblique (Greenspan view)
Radial head classification system name
Mason
Mason classification system
Type 1: nondisplaced fx
Type 2: marginal fx with displacement (impaction, depression, angulation)
Type 3: comminuted fx involving entire head
Type 4: associated with dislocation of the elbow (Johnston)
Relative indications (2) for operative tx of partial radial head fxs? Exposure used? Describe the safe zone in this tx?
Displacement of a large fragment >2 mm without a block to motion, or fx with block of motion. Kocher exposure. Safe zone is within 90 degree arc between the radial styloid and Lister tubercle
Optimal fx for ORIF of radial head fxs and tx
Three or fewer articular fragments without impaction or deformity, each should be of sufficient size and quality to accept screw, little or no metaphyseal bone loss. Reconstruct with screws and place plate posteriorly with arm supinated.
Eponym for Spiral fx of the distal radius resulting in compression/laceration of the radial nerve
Holstein-Lewis fracture
Fracture-dislocation of elbow with associated coronoid process is secondary to:
Avulsion by brachialis muscle
Types of Elbow Instability
Posterolateral rotatory instability, Varus posteromedial rotation instability, Olecranon fx-dislocations
Instability scale (Morrey) for elbow dislocations
Type 1: Posterolateral rotatory instability, positive pivot shift test, lateral ulnar collateral ligament disrupted.
Type 2: Perched condyles, varus instability, lateral ulnar collateral ligament, anterior and posterior capsule disrupted.
Type 3a: Posterior dislocation, valgus instability, lateral ulnar collateral ligament, anterior and posterior capsule, and posterior MCL disrupted.
Type 3b: Posterior dislocation, grossly unstable, lateral ulnar collateral ligament, anterior and posterior capsule, anterior and posterior MCL disrupted
Three general approaches to failed nonop tx of elbow dislocations:
Open reduction and repair of soft tissues back to the distal humerus, hinged external fixation, cross-pinning of the joint
