RA Finger Deformities 3

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

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