Functional outcome comparison of semiconstrained and unconstrained total elbow arthroplasties.
Twenty-six patients, each of whom had undergone either a semiconstrained (linked) or an unconstrained (unlinked) total elbow arthroplasty, were examined specifically to evaluate the restoration of function with respect to activities of daily living. The functional outcomes of these 2 groups were then compared to identify any significant differences. All of the unlinked/unconstrained prostheses were Ewald total elbow arthroplasties; the linked/semiconstrained prostheses, all of which were performed by a single surgeon, were Mayo-Coonrad prostheses. Follow-up radiographs, taken to rule out loosening or failure of the prosthesis as a cause for functional deficits, were available for review for 25 elbows. There were 14 elbows in 13 patients who had semiconstrained prostheses and 12 elbows in 10 patients who had unconstrained total prostheses. Average age at the time of elbow replacement surgery was 62.8 years (range, 47-75 years) for the semiconstrained group and 63.1 years (range, 54-74 years) for the unconstrained group. The semiconstrained group consisted of 8 female and 6 male elbows; the unconstrained group consisted of 10 female and 2 male elbows. Follow-up averaged 35.5 months (range, 24-73 months) in the semiconstrained group and 73 months (range, 27-110 months) in the unconstrained group. Twenty-two operations were performed for rheumatoid arthritis, 3 for posttraumatic humeral nonunion, and 1 for posttraumatic degenerative arthritis. Two elbows required revision, one (in the semiconstrained group) for aseptic loosening and the other (in the unconstrained group) for metal synovitis and pain from a chronically dislocated prosthesis; both of these elbows were considered failures and excluded from the functional comparison. No significant differences in functional performance were found, and no elbows demonstrated progressive radiolucencies suggestive of loosening. With the exception of 1 patient (in addition to the patients who had revisions) with a dislocated unconstrained prosthesis, all patients were satisfied with the procedure. It appears that when it is properly performed, total elbow arthroplasty with either type of prosthesis yields satisfactory functional results.