Metacarpophalangeal hyperextension in thumb basal joint osteoarthritis: Radiological study and implications for treatment.

We report a series of 95 consecutive patients operated on for total trapeziometacarpal joint replacement, screening for radiological characteristics to differentiating patients with and without preoperative MCP hyperextension. Loss of thumb column length and metacarpal head circularity on lateral view were quantified. Statistically, a combination of reduced length and circular metacarpal head was a determining factor for MCP hyperextension. We therefore believe it is essential to restore thumb column length in surgery for trapeziometacarpal osteoarthritis and to avoid trapeziectomy in patients with a circular head on lateral view. LEVEL OF EVIDENCE: III; prospective cohort study.