OrthoNet

Finger Deformities 3
TENDON RUPTURE

Extensor Tendon

- basically caused by rheumatoid tenosynovitis
- the long extensors of the middle, ring, and little fingers rupture as a group - usually related to the dorsal subluxation of the distal ulna, forcing the tendons to rub up against the rough bone and the dorsal carpal ligament
- acutely, direct repair may be done.
- chronically, a segmental tendon graft will be required
- potential graft sources are the extensor indicis, EPB (especially when the MCP is going to be fused anyways), or sublimis to the ring finger

Flexor Tendon

- not as common to rupture as the extensor tendons, but harder to treat
- tendon grafts almost always fail.
- FPL rupture may be treated with thumb IP fusion

ARTHRODESIS OF THE FINGER JOINTS

- preferred position for arthrodesis:
MCP - 20-30o flexion
PIP - 25o flexion in the index to 40o in the small
DIP - 15-20o flexion

DEFORMITIES OF THE THUMB

- Nalebuff classification of thumb deformities in rheumatoid patients

Type I: boutonniere deformity
- synovitis at the MCP stretches the extensor hood; the EPL migrates medially and causes flexion of the MCP joint, extension of the IP joint, and volar subluxation of the proximal phalanx
- if mild, MCP synovectomy and extensor reconstruction suffice
- if severe, MCP arthrodesis (if IP and CMC joint function are intact)
- if IP and CMC are involved, MCP arthroplasty may be better

Type II: MCP flexion, IP hyperextension, plus CMC subluxation
- treat with all of the above plus CMC arthroplasty

Type III: swan neck deformity
- begins with synovitis at the CMC joint, subluxing the trapeziometacarpal joint laterally; an adduction contracture of the metacarpal develops, and the MCP joint hyperextends as the result of the extension forces on the MCP joint and laxity of the volar plate.
- if mild, trapeziometacarpal interposition arthroplasty
- if the MCP joint is very deformed, both trapeziometacarpal interposition arthroplasty and MCP fusion may be necessary

Type IV: ulnar collateral ligament laxity (Gamekeeper�s thumb)
- for mild deformities, synovectomy, ligament reconstruction and adductor release
- for severe deformities, MCP arthrodesis

RHEUMATOID DEFORMITIES OF THE WRIST

- the wrist may be the first location of painful swelling
- persistent swelling at the dorsum of the wrist for 6 weeks failing medical treatment may be an indication for synovectomy, as prophylaxis against extensor tendon rupture
- on the volar surface, even a small bit of tenosynovitis can cause carpal tunnel syndrome
- the level of the deep transverse carpal ligament is a frequent site of rupture of flexor tendons

Arthrodesis

- whether arthrodesis or arthroplasty is best in the wrist is controversial.
- arthrodesis provides a painless, stable wrist with the chance to correct deformity
- most consider it the procedure of choice for marked flexion deformity of the wrist and fingers, for carpal dislocation, or for a painful wrist with associated tendon ruptures