This retrospective review is an intermediate term follow-up of total elbow arthroplasties performed by one surgeon using three different prostheses: Souter-Strathclyde, Kudo, and Coonrad-Morrey, for the treatment of rheumatoid arthritis. A posterior triceps tendon turndown was utilized in each patient. The anterior band of the medial collateral ligament was preserved, except for patients undergoing a Coonrad-Morrey. Antibiotic impregnated cement was used in all patients without cement restrictors. Follow-up was performed at a mean of between 61-68 months. This showed adequate pain relief in the majority of patients in all groups. The preoperative flexion deformity was not significantly diminished by any of the three prostheses. Flexion, however, improved by 20 degrees with the Souter-Strathclyde, 14 degrees with the Kudo implant and 10 degrees with the Coonrad-Morrey implant. There was one infection in the Souter-Strathclyde and 2 in the Coonrad-Morrey and none in the Kudo prosthesis. There was no instability seen in the semi-constrained Coonrad-Morrey, but 1 persistent instability with the Souter-Strathclyde and 2 with the Kudo prosthesis. There were no documented triceps problems. The five-year survival rates related to revision and radiographic signs of implant loosening were 85% and 81% for the Souter-Strathclyde implant, 93% and 82% for the Kudo implant, and 90% and 86% for the Coonrad-Morrey implant. With revision used as the end point, the Coonrad-Morrey prosthesis was found to have a better survival rate. The mode of loosening was characterized as tilting of the tip of the humeral stem anteriorly with migration of the articular portion posteriorly in the Souter-Strathclyde implant whereas the pattern of loosening of the Kudo implant was less predictable.
This is the first known comparative study evaluating intermediate term follow-up of total elbow arthroplasties performed in patients with rheumatoid arthritis using three separate prostheses. Pain was adequately relieved in all groups. Range of motion of the elbows was not significantly improved, but the five year survival rate with revision surgery at the end point showed that the Coonrad-Morrey and Kudo devices had a higher survival rate than the Souter-Strathclyde implant. There was noted to be an incidence of 16 % ulnar component loosening in the Coonrad-Morrey group. This study confirmed a slightly higher rate of instability with unconstrained devices (as expected), but did not support a significantly higher risk of loosening with the semi-constrained devices. However, the ulnar component loosening observed in this group is somewhat worrisome. Longer term follow-up of these patients may be beneficial to further elucidate the advantages and disadvantages of each of these prostheses. However, at present, there does not appear to be substantial evidence to favor a non-constrained implant over a semi-constrained device in this population.
Elbow, Arthritis, Arthroplasty, Outcome, Rheumatoid
Journal of Bone and Joint Surgery