Instability is a recognized complication associated with unlinked total elbow implants. The best form of treatment of this problem is uncertain as very little has been written about it.
Twelve patients underwent operative treatment of instability at the site of a capitellocondylar unlinked total elbow replacement, and the results were reviewed retrospectively. The study group included ten women and two men with an average age of fifty-eight years. Ten patients had rheumatoid arthritis. Three elbows underwent conversion to a semi-constrained hinged prosthesis. In the other nine elbows, an attempt was made to continue with an unlinked prosthesis: three had reconstruction of one or both collateral ligaments, four had component revision, and two had both ligament reconstruction and component revision.
After an average duration of follow-up of six years (range, two to fifteen years) only three patients had retained a functioning unlinked prosthesis. Of the remaining nine patients, three had had a conversion to a semi-constrained arthroplasty at the time of the index procedure, four had had a conversion to a semi-constrained prosthesis at the time of a salvage procedure, one had had a resection arthroplasty, and one had a painfully dislocated elbow and had declined revision. Thus, seven elbows eventually underwent conversion to a semi-constrained prosthesis; these conversion procedures were technically difficult, with perforation of the humerus occurring in six patients and perforation of the ulna occurring in four. After all procedures, the average elbow flexion was 132 degrees and the average flexion contracture was 25 degrees. According to the Mayo Elbow Performance Index, there were four excellent results, three good results, three fair results, and one poor result.
Revision of an unlinked total elbow prosthesis to a linked total elbow prosthesis is difficult, but it restores elbow function. Although the present series documents the unpredictability of attempts to salvage an unstable unlinked prosthesis, it seems reasonable to attempt at least one soft-tissue procedure before converting to a linked prosthesis.