Hyperextension of the thumb metacarpophalangeal (MCP) joint is frequently seen with trapeziometacarpal osteoarthritis, but there is no consensus on the indication for, or type of, treatment. We re-examined 12 thumbs at a mean of 9 (range 6–13) years following MCP capsulodesis using a suture anchor performed with trapeziectomy. Mean MCP hyperextension improved from 45° pre-operatively to 19° at 1 year post-operatively. At 9 years follow-up, it had increased to 30° but was still significantly better than pre-operatively ( p = 0.007). Mean MCP flexion was 37° and near normal opposition was retained. The median pain score had improved from 5.5 to 1 ( p = 0.002). Thumb key and tip pinch and hand grip strength showed no significant change from pre-operative values. No thumb MCP had symptomatic radiological degeneration. Our results suggest that MCP capsulodesis preserves a useful range of MCP flexion but stretches out over time. However, this did not result in increased pain or thumb weakness.