Abstract
Purpose: Loosening remains a problem with semi-constrained total elbow prostheses. The trend in recent years has been to improve prosthesis design to achieve stability of the humeral implant. We report a small series of nine Coonrad-Morrey total elbow prostheses where three early loosenings were observed in the ulnar implant. We attempt to analyse the causes and present a review of the recent literature.
Material and methods: Nine patients, mean age 60 years, age range 57–63 years, underwent total elbow arthroplasty with a Coonrad-Morrey prosthesis for rheumatoid disease (n=5), stiff degenerative joints after trauma (n=3, flexion-extension 20°), floating joint after trauma (n=1). The posterolateral approach described by Bryan and Morrey was used for eight elbows and the posterior approach for one. Clinical and radiological results were assessed with the performance index and the Mayo clinic score respectively.
Results: Mean follow-up was 3.6 years (1.5–4.7). Outcome was very good or good for seven elbows (score > 75 and > 50), fair for one (< 50) and poor for one (< 25). Three elbows were pain free, two presented pain during movement against force. Flexion was greater than 120° in four elbows (all four rheumatoid polyarthritis). Radiologically, we observed three cases of ulnar implant loosening with two type IV lucent lines, and one type III line. There was one humeral implant with a lucent line which did not change over time (type I). The two cases of type IV lines were associated with radial and anterior translation migration of the prosthetic stem with effraction or lysis of the ulnar cortical. The three ulnar loosenings appeared between the second and third postoperative year on two post-trauma stiff degenerative elbows (flexion-extension < 20°) and one rheumatoid elbow. At last follow-up, there was one poor result requiring revision surgery, one fair result, and one very good result (totally asymptomatic type 4 lucent line).
Discussion: The causes of these loosenings were studied: difficult cementing technique in a tight canal, mediocre primary stability of the ulnar implant opposing the excellent fit of the humeral implant with an encased graft under the anterior wing, excessive constraint. Our results are similar to those reported by Hilebrand who had 30% evolving ulnar lucent lines and suggest that we should reserve this prosthesis for unstable elbows.
The abstracts were prepared by Docteur Jean Barthas. Correspondence should be addressed to him at Secrétariat de la Société S.O.F.C.O.T., 56 rue Boissonade, 75014 Paris.
