Functional outcome of semiconstrained total elbow arthroplasty.
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BACKGROUND: The objective of the present study was to review the results of primary total elbow arthroplasty with use of the Coonrad-Morrey prosthesis. Two hypotheses were tested: (1) the results in patients with inflammatory arthritis would be superior to those in patients with a traumatic or posttraumatic condition, and (2) the isometric extensor torque after total elbow arthroplasty would be significantly less than that of the contralateral elbow. METHODS: Forty-seven consecutive patients (fifty-one elbows) had the operation performed by one of three surgeons between November 1, 1989, and June 30, 1996. Thirty-six surviving patients (thirty-nine elbows) were available for follow-up. The mean duration (and standard deviation) of follow-up was 50 +/- 11 months (range, twenty-four to ninety-seven months). The mean age at the time of the operation was 64 +/- 11 years (range, twenty-seven to eighty-seven years). Eighteen patients (twenty-one elbows) had inflammatory arthritis. Eighteen patients (eighteen elbows) had an acute fracture or posttraumatic condition (posttraumatic osteoarthritis in eight, an acute fracture of the humerus in seven, nonunion of the distal aspect of the humerus in two, and primary osteoarthritis in one). The patients were evaluated with use of questionnaires (the Mayo elbow performance index, the Short Form-36 [SF-36], and the Disabilities of the Arm, Shoulder and Hand [DASH] Questionnaire); clinical examination by an orthopaedic surgeon who was not involved with the pre-operative, operative, postoperative, or follow-up care; radiographs; and elbow strength-testing with an isokinetic dynamometer. RESULTS: The mean score (and standard deviation) on the Mayo elbow performance index for the group that had inflammatory arthritis (90 +/- 11 points) was significantly higher than that for the group with a traumatic or posttraumatic condition (78 +/- 18 points) at the time of the latest follow-up (p < 0.05). In both groups, the mean extensor torque of the involved elbow was significantly less than that of the contralateral elbow (p < 0.05). No significant difference between the groups was found with respect to the flexion-extension arc of motion. Ten elbows (26 percent) had ulnar nerve dysfunction (a transient deficit in six and a permanent deficit in four); nine (23 percent), an intraoperative fracture (of the humeral diaphysis in four, of the ulnar diaphysis in four, and of the olecranon in one); three (8 percent), a periprosthetic infection; three, a triceps disruption; and one (3 percent), a revision because of a fracture of the ulnar component. There were no other revisions. Of the thirty-four elbows with complete radiographic follow-up, twenty-three had no change in the bone-cement interface. Progressive radiolucency was noted around the ulnar prosthesis in eight elbows, around the humeral prosthesis in one elbow, and around both components in two elbows. CONCLUSIONS: Patients who had a total elbow arthroplasty with use of a semiconstrained Coonrad-Morrey prosthesis were generally satisfied; the mean level of patient satisfaction was 9.2 of a possible 10 points for those who had inflammatory arthritis and 8.6 points for those who had a fracture or posttraumatic condition. The rates of complications involving the ulnar nerve, intraoperative fracture, triceps disruption, deep infection, and periprosthetic radiolucency are of concern.