Abstract
Purpose: Consolidation of the tuberosity is the key to success of shoulder arthroplasty for fracture. The purpose of this study was to assess the number and causes of tuberosity complications in order to find solutions for this problem.
Material and methods: This retrospective multicentric study included 334 shoulder prostheses implanted for fracture between 1991 and 2000. Two different prostheses were used: 300 standard Aequalis prostheses implanted between 1991 and 1997 (mean follow-up four years) and 31 Aequalis Fracture prosthesis between 1999 and 2000 (mean follow-up nine months). Radiological results were assessed on the postoperative and last follow-up x-rays. The Constant score was used for clinical assessment.
Results: For the 300 standard prostheses, the Constant score was 54 points with active anterior elevation = 104°. For the 31 fracture prostheses, the Constant score was 58 points with active anterior elevation = 114°. According to the operator’s assessment, 49% of the postoperative radiological results were fair or poor and objectively 35% of the tuberosities were poorly positioned with the standard prosthesis and 22% with the fracture prosthesis. Twenty-six percent of the good or poorly positioned tuberosities migrated secondarily with the standard prosthesis and 10% with the fracture prosthesis. Statistically significant prognostic factors limiting tuberosity complications were: satisfactory initial osteosynthesis with correct prosthesis height and retroversion facilitated by use of the fracture system, rehabilitation in a specialised centre, relative immobilisation during the first postoperative month limiting exercises to balancing movements which divided the number of secondary migrations by two compared with immediate moblisation (14% versus 27%).
Discussion: A precise analysis of the radiograms revealed a very high rate of tuberosity complications (50%). There has been little study of these complications which are underestimated in the literature. The Aequalis fracture prosthesis can reduce these tuberosity complications two-fold. Postoperative immobilisation also reduces two-fold tuberosity migrations. These observations are against the early passive motion advocated by Neer. Finally, the quality of tuberosity fixation is crucial for success. The surgeon must concentrate on this element, searching to achieve a perfectly positioned prosthesis on the peroperative x-ray.
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.
