Locking mechanism failure in semiconstrained total elbow arthroplasty.

Between 1988 and 2000, we performed 170 total elbow replacements using a semiconstrained implant (custom or standard). We are aware of 9 implants (5.3%) that have had late failure of the locking mechanism, as evidenced by migration of the connecting axle on radiographic examination. The mean time to failure of the locking mechanism was 5.5 years. Eight elbows required surgery for revision of the polyethylene bushing and locking mechanism by use of a custom-made locking clip. A limited approach was devised that allowed sufficient exposure to change the bushing and axle. In 1 of the 8 cases, the revised locking mechanism failed at 5.5 years, necessitating a reoperation. Of the 8 patients, 7 have not had recurrence of the failure at a mean of 1.4 years (minimum follow-up of 1 year). These 7 patients have good or excellent results based on the Hospital for Special Surgery elbow scoring system, with a mean arc of motion of 130 degrees.