Midcarpal Instability

Midcarpal instability (MCI) is an uncommon form of nondissociative carpal instability, although it is an important cause of diffuse and ulnar sided wrist pain. The abnormality and instability lie between the proximal and distal carpal rows, and the bones of the proximal carpal row remain linked together (“nondissociated”). Diagnosis can be difficult and requires examiner suspicion and comfort with a series of key provocative tests, most notably a “clunk” with the midcarpal shift testing. Nonsurgical management, including splinting and selective muscle strengthening in therapy, and surgical management, including arthroscopic thermal capsulorrhaphy, soft tissue reconstruction, and limited intercarpal fusions, are considered. Limited series have shown good results with these procedures in the short- and mid-term, though more long-term follow-up studies are needed.