Review Question - QID 217909

The ideal position for arthrodesis of the thumb MCP joint is in 20-25 degrees of flexion, which optimizes key pinch.

Thumb MCPJ arthritis has many etiologies ranging from rheumatoid arthritis, osteoarthritis, post-traumatic arthritis, and chronic joint instability. Various nonsurgical treatment options have been shown to be effective, including activity modification, systemic and topical anti-inflammatory medications, splinting, and cortisone injections. For patients with rheumatoid arthritis, newer-generation disease-modifying antirheumatic drugs have shown to be effective. As far as operative intervention for the thumb MCPJ, silastic arthroplasty is an option, but arthrodesis remains the gold standard. The majority of thumb motion occurs at the carpometacarpal and interphalangeal joints, and, as such, arthrodesis of the thumb MCP is well tolerated.

Saldana et al. performed an anatomic study to determine the most optimal position of the thumb metacarpophalangeal joint during arthrodesis. They evaluated thirteen positions of function for different tasks in two hundred joints in normal subjects. The mean of all thirteen measured positions was considered the "optimal functional position". Based on this study, they concluded that the metacarpophalangeal joint of males is fused in approximately 25 degrees of flexion and females in 20 degrees of flexion.

Rizzo published a review on arthritis of the metacarpophalangeal joint, including non-operative and operative modalities. He reports that thumb MCPJ arthritis is most commonly treated with arthrodesis, whereas arthroplasty remains the most common treatment option for other finger MCPJ arthritis. He discusses traditional constrained silicone joint replacements as well as newer generation unconstrained, surface replacement arthroplasties.

Incorrect Answers:
Answers 1-4: The ideal position for arthrodesis of the MCP joint is in 20-25 degrees of flexion, which optimizes key pinch.