Hand and Wrist Flashcards
Site of compression of the median nerve
Supracondylar process/ligament of Struthers
Lacertus fibrosus
Between humeral and ulnar heads of Pronator teres
Fibrous origin of FDS (sublimus bridge)
Ganzer’s accessory FPL (AIN compression)
Sites of compression of ulnar nerve
Medial intermuscular septum
Arcade of Struthers
Hypertrophied medial head of triceps
Cubital tunnel (Osborne’s ligament)
Anconeus epitrochlearis
Between humeral and ulnar heads of FCU
Deep flexor-pronator aponeurosis
Sites of compression of radial nerve
FREAS
Fibrous bands proximal to radiocapitellar joint
Radial recurrent vessels (Leash of Henry)
ECRB leading edge
Arcade of Frohse
Supinator (as it exits)
Order of innervation of Radial nerve and PIN
Radial
Triceps, lateral 1/3 of brachialis, anconeus, brachioradialis, ECRL
PIN
ECRB, Supinator, ECU, EDC, EDM, APL, EPL, EPB, EI
Order of innervation of ulnar nerve
FCU, FDP 3&4, ADM, ODM, FDM, Lumbricals 3&4, Deep head FPB, Adductor pollicus, Interossei
Order of innervation of median nerve / AIN
AIN
FDP 1&2
FPL
PQ
Median
PT, FCR, PL, (AIN) FDS, APB, FPB (superficial), OP, Lumbricals 1&2
Principles of tendon transfers (8)
SADISSMS
Strength (Will lose 1 power grade)
Amplitude (Equal excursion)
Direction (straight line of pull)
Integrity (one tendon, one function)
Synergism
Sensate joint
Mobile joint
Soft tissue coverage
Tendon transfers for high radial nerve palsy and PIN palsy
Elbow extension
Deltoid/lat dorsi/biceps to triceps
Wrist extension
PT to ECRB
**When only PIN out, do side to side ECRL to ECRB
Digit extension
FCR to EDC
Thumb extension
PL (or FDS long/ring) to EPL
Transfers for a low median nerve palsy
Opponensplasties
Bunnell: FDS (ring) to base of prox. phalanx or APB (using FCU as a pulley)
Burkhalter: EIP to APB
Camitz: PL to APB
Huber: ADM to APB
Tendon transfers for high median nerve palsy.
Thumb opposition
Opponensplasty (can’t use FDS! Use EIP)
Index/long flexion
FDP ring/small to FDP index/long
Thumb IP flexion
Brachioradialis to FPL
Tendon transfers for ulnar nerve palsy
Thumb pinch
FDS (ring) or ECRB* to adductor pollicis
Index pinch
EIP or APL slip to 1st dorsal interosseous
Ring/Small clawing
FDS to radial lumbrical insertion (Stiles Bunnell)
(another option for claw digit: Zancolli Lasso - FDS cut, woven back over A1 pulley to itself)
*ECRB may require graft for required length
Thumb tendon insertions:
APB/FPB/OP
APL/EPB/EPL
APB: prox phalanx
FPB: prox phalanx
OP: metacarpal
APL: metacarpal
EPB: base prox phalanx
EPL: base distal phalanx
Name the classification for basal joint thumb arthritis.
Bonus: Name of basal thumb AP xray
Eaton & Littler
- Slight joint narrowing
- Sclerotic CMC, osteophytes <2mm
- Osteophytes >2mm
- Pan-trapezial OA
Roberts view
Contributions to DRUJ stability
DRUL: primary stabilizer of dorsal displacement of radius
PRUL: primary stabilizer of palmar displacement of radius
Bony DRUJ: confers approx 20% of DRUJ stability
Distal IOM: contributes to dorsal stability of radius
ECU sheat and Ulnocarpal ligs: contribute minimally to DRUJ stability.
Outline classification and mgmt of Kienbock’s dz
Lichtman classification:
- Normal xray (cast 6 weeks)
- Lunate sclerosis
3A. Lunate collapse with NO scaphoid rotation
(Tx is forage/decompression, vasc BG to lunate, capitate shortening osteotomy, radial wedge if ulnar positive, radial shortening if ulnar negative)
3B. Lunate collapse WITH scaphoid rotation
(Tx is lunate excision with STT/SC fusion; or PRC)
- Pancarpal OA
(Tx is wrist fusion)
Percunateously fixed scaphoid fractures vs cast treatment?
Faster rate of healing
Earlier return to work
In a DISI deformity, what does the scaphoid do?
Flexes and PRONATES
Mayfield classification
- Scapholunate
- Scaphocapitate
- Lunotriquetral
- Volar lunate dislocation
Stages of SLAC wrist and stages of SNAC wrist
SLAC
- Arthritis b/w scaphoid and radial styloid
- Arthritis of whole scaphoid fossa
- Capitolunate arthritis
SNAC
- Arthritis b/w scaphoid and radial styloid
- Scaphocapitate arthritis
- Capitolunate arthritis
Periscaphoid arthrosis (proximal lunate and capitate may be maintained)
Both end off with pan carpal arthritis.
List xray findings of scapholunate dissociation.
AP
Widened SL interval, scaphoid(signet)ring sign, triangular shaped lunate (extended lunate), widened triquetrum (from also being extended), decreased carpal height ratio (<54%)
Lateral
SL angle >60degrees, Lunate/triquetrum dorsiflexed (DISI), Radiolunate angle >15deg, Carpal V sign of Taleisnik (normally volar margins of scaphoid and DR assume a C shape)
How do you measure the carpal height ratio?
Carpal height/3rd MC length
Carpal height: distance between DR articular surface and distal articular surface of capitate
Average is 54%
Explain Bunnell test for intrinsic muscle tightness
More PIP flexion with MCPs flexed than with MCPs extended.
MCP extension places intrinsics on stretch.
MCP flexion relaxes intrinsics.
Explain how to test for extrinic extensor tightness
Flexion range of PIPs is less with MCP flexion than with MCP extension.
MCP flexion places extrinsics on stretch, and MCP extension relaxes extrinsics.
(Essentially opposite of Bunnell test.)
Rheumatoid thumb. What is most common deformity?
Treatment?
Thumb boutonniere!
Etiology: MCP synovities, attenuation of dorsal capsule and EPB tendon (hence, often have extensor lag of thumb MCP)
Stage 1: flexible deformities (can do synovectomy of MCP and pin MCP in extension for 4 weeks)
Stage 2: Fixed MCP deformity, flexible IP. Fuse MCP.
Stage 3. BOTH fixed deformities. Fuse IP. Fuse MCP if CMC ok, if not then do MCP arthroplasty.
Re: EPL. Can lengthen if tight. Should tenodese to EPB to restore MCP extension.
(IP hyperextension and MCP flexion)
Dupuytren’s associations (3)
Peyronie’s dz (penile fascia)
Ledderhose disease (plantar fascia)
Garrod disease (knuckle pads)
Clinically relevant cords in Dupuytren’s disease
Central cord: causes MCP joint contracture
Spiral cord: causes PIP joint contracture
Natatory cord: webspace contracture (adduction contracture of digit)
Structures involved in spiral cord (5)
BONUS: What does the spiral cord do to the neurovascular bundle?
Pretendinous band
spiral band
natatory band
lateral digital sheet
grayson’s ligament
Spiral cord displaces NV bundle CENTRALLY and SUPERFICIALLY
Swan neck!
Causes (4)
Classification
Treatment
Causes: PIP synovitis (attenuated volar plate), FDS rupture, Mallet injury, intrinsic tightness from MCP subluxation/dislocation
Classification (Nalebuff) & Treatment
- Supple: Ring splint (nonop).
Operative: DIP fusion (if mallet is the cause); FDS tenodesis; volar plate advancement; ORL reconstruction.
- PIP stiff in MCP extension. Release intrinsics
- PIP stiff in all positions. Mobilize lateral bands and do central slip tenotomy to release PIP
- Arthritic PIP: Fuse at 20/30/40/50
Boutonniere!
Causes (2)
Classification and Treatment
BONUS: Which physical exam test?
Causes: PIP synovitis and attenuation of central slip; traumatic central slip avulsion/laceration
**Elson test**
Central slip rupture causes tightness and volar subluxation of lateral bands which extends the DIP
Classification (Nalebuff) & Treatment
- Supple PIP
Acute: splint PIP extension. Fix if avulsion #.
Chronic: Splint PIP extension. Synovectomy. Can release terminal extensor if fixed DIP extension.
- Marked flexion of PIP
Mobilize lateral bands dorsally, reconstruct triangular ligament. Reinsert central slip.
- Arthritic PIP: Fuse at 20/30/40/50
Complex MCP dislocation.
Direction of flexor/lumbrical for index and for small finger.
Direction of ADM and FDM for small finger
Bonus: which structure lies distal to metacarpal head? Proximal?
Index
Flexor goes ulnarly, lumbrical goes radially
Small
Flexor and lumbrical go radially
FDM/ADM go ulnarly
Bonus: Natatory ligament lies distal to MC head and superficial transverse MC ligament lies proximal.
List management algorithm for dorsal PIP fracture-dislocation
If fracture involves <40% of articular surface of base of middle phalanx:
Dorsal extension block splint at 30deg. Increase by 10 deg per week.
If >40%:
ORIF, cerclage wiring, hemihamate autograft, dynamic distraction exfix, volar plate advancement/arthroplasty.
Common deformities in proximal and middle phalanx fractures and forces behind them.
Proximal phalanx: usually apex volar. Central slip acts distally to extend, intrinsics act on proximal fragment to flex.
Middle phalanx: Apex dorsal if fracture proximal to FDS insertion (central slip extends).
May be apex volar if fracture distal to FDS insertion
Acceptable reduction criteria for proximal and middle phalanx fractures.
Do not accept any rotation.
Alignment up to 10deg
Up to 2mm shortening
In absence of EPL, what muscles can extend the IP thumb joint to neutral?
Abductor pollicis brevis and adductor pollicis (insert into EPL tendon).
Thumb sesamoids are within which tendons?
Radial sesamoid: FPB tendon
Ulnar sesamoid: Adductor pollicis tendon
With dorsal thumb MCP dislocation, the sesamoids follow the proximal phalanx dorsally when which aspect of the volar plate is rupture? (ie proximal or distal)
Proximal volar plate rupture - the sesamoids will follow the proximal phalanx.
What are the deforming forces of a Bennett’s fracture?
Describe the reduction maneuver:
Bonus: which ligament holds the intraarticular fragment in place?
Adductor pollicis: adducts (ulnar angulates) and supinates the metacarpal shaft.
Abductor pollicis longus (and EPL/EPB): Displaces metacarpal shaft/base proximally, dorsally and radially.
Reduce with traction, pronation, abduction & extension.
Anterior oblique (beak) ligament keep volar-ulnar base fragment anchored to trapezium
Accept what amount of angulation for nonop treatment of extraarticular thumb MC base fracture?
30degrees
Acceptable position of MC neck fractures
index/long: 10-15 degrees
ring: 40 degrees
small: 60 degrees
Acceptable position for metacarpal shaft fractures
Bonus: deforming forces of MC shaft?
Alignment:
Up to 10degrees for index/long
Up to 30deg for ring/small & THUMB
Shortening up to 5mm
Less than 5 degrees of rotation (preferably none)
Deforming forces: interossei and flexor tendons create apex DORSAL angulation
Order of pulleys!
A5 at DIP
C3
A4
C2
A3 at PIP
C1
A2
A1 at MCP
Superficial palmar arch - supplied by? Supplies what?
Deep palmar arch - supplied by? Supplies what?
Superficial - supplied by ulnar artery. Main supply to digits.
Deep - supplied by radial artery. Supplies thumb and radial side of index.
Interossei - describe structure
4 dorsal bipennate. 1st and 2nd insert on radial side of index and long proximal phalanges respectively. 3rd and 4th insert on ulnar side of long and ring proximal phalanges respectively.
3 palmar unipennate. 1st insert on ulnar side of index proximal phalanx. 2nd and 3rd insert on radial side of ring and small proximal phalanges respectively. (Remember they originate from the same digit they insert on)
Describe zones of flexor tendon injury
Zone 1: distal to FDS insertion
Zone 2: from distal palmar crease to FDS insertion
Zone 3: from carpal tunnel to the distal palmar crease
Zone 4: within carpal tunnel
Zone 5: proximal to carpal tunnel
Outline Leddy & Packer classification
What to avoid when repairing these and why?
Classification of zone 1 flexor tendon (FDP) injury
- Tendon retracted into palm. Means VLP and VBP are disrupted. Fix within 7-10 days
- FDP still within sheath. VLP usually preserved. Fix within a couple weeks.
- Bony fragment avulsion, retracts to A4 pulley. Fix within a couple weeks.
- Avulsion fracture with subsequent separation of tendon from avulsed piece. ORIF piece then repair tendon as if 1/2
***Don’t advance FDP more than 1cm - can cause Quadrigia
Camptodactyly
What is it and briefly outline treatment
Flexion deformity of PIP joint (usually in ulnar sided digits)
Treated usually w/ stretching.
If progressive and disabling, can release volar structures (plate, FDS).
IF joint supple, transfer FDS to lateral bands to aid IP joint extension
Symphalangism
What is it? Treatment?
Failure of IP joint to form.
Observation!
Clinodactyly
What is it? Treatment?
Lateral deviation of digit.
Usually small finger radial deviation.
Often observe. Can operate if presence of dysfunction and if Delta phalanx present
Wassel classification of preaxial polydactyly?
- Bifid distal phalanx
- Duplicated distal phalanx
- Bifid prox phalanx
- Dup prox phalanx (most common)
- Bifid MC
- Dup MC
- Triphalangeal thumb
Most preaxial polydactyly is sporadic but what is triphalangeal thumb associated with?
Holt Oran, Fanconi Anemia, Diamond-Blackfan anemia, hypoplastic anemia, imperforate anus, cleft palate, tibial defects.
Martin Gruber anastomosis?
Occurs in the forearm. Motor fibres from median nerve cross over to ulnar nerve.
Clinically it means that in a high ulnar nerve injury, the expected motor loss in the hand may not be observed. Median fibres are contributing to motor function in the hand normally just performed by the deep branch of the ulnar nerve.
Riches-Cannieu anastomosis?
Ulnar-to-median communication of motor fibres in the hand.
Clinically may see preserved median (thenar) function despite a higher median nerve injury.
Xray findings of Madelung’s deformity
Proximal lunate migration (“pyramidalization” of the carpus); Anterior radial bow; Dorsal prominence of ulnar head.
McCarroll criteria (4)
- Ulnar Tilt [90 – (Ulna:Tangent SL)] = > 33°
- Lunate subsidence > 4 mm
- Lunate fossa angle [90 – (Ulna:Lunate fossa)] = > 40°
- Palmar carpal displacement: Long axis ulna to the volar lunate or capitate > 20mm
Seddon classification
Neuropraxia
Myelin disrupted. Axon intact. Endoneurium intact. No wallerian degen
Axonotmesis
Myelin disrupted. Axon NOT intact. Endoneurium intact. YES wallerian degeneration
Neurotomesis
Myelin disrupted. Axon NOT intact. Endoneurium NOT intact. YES wallerian degeneration.
Maneuvers for assessment of pronator syndrome?
- Pronator compression test
- 30s of pressure proximal and just lateral to origin of pronator. Should reproduce sx. - Resisted pronation
- Will reproduce sx if pronator is site of compression - Resisted supination
- Will reproduce sx if lacertus is site of compression - Resisted PIP flexion of long finger.
- Will reproduce sx if proximal edge of FDS is site of compression - Volar forearm Tinel
