OUTCOME OF SHOULDER PROSTHESIS FOR DEGENERATIVE DISEASE SECONDARY TO GLENOHUMERAL DYSPLASIA

Abstract

Purpose of the study: Glenohumeral dysplasia is an uncommon cause of degenerative disease of the shoulder joint. In this context, arthroplasty is a therapeutic challenge due to the bony deformations.

Material and methods: Between 1998 and 2004, simple humeral prostheses were implanted in eight shoulders (seven patients, two men and five women, mean age 49.5 years). There was no procedure on the glenoid cavity. A Neer II was used for four shoulders (two dysplasic cases with short 63 mm stems) and a Neer III for four shoulders.

Results: At mean follow-up of 4.5 years (maximum 7 yers) the Neer outcome was satisfactory for five patients and non-satisfactory for two. Five of the seven patients were satisfied with their operation. The Constant scores improved: from 3.5 to 11.8 for pain, 9.8 to 16.6 for activity, and 13.8 to 24.4 for active mobility. Active anterior elevation was 114° on average, external rotation 25°, and internal rotation at level L3. The overall constant score was 52.8 points with a weighted score of 43%. Radiographically, there were no lucent lines around the humeral implant. Anterior dislocation occurred in one shoulder six months after the initial operation. Capsuloligament revision was performed but the implant was left in place. For one other shoulder, secondary rotator cuff tears limited the function outcome, but the prosthesis was not revised.

Discussion and conclusion: The results were average, but did allow our patients to resume nearly normal activity without pain. Looking at the failures in this small series suggests that the status of the rotator cuff is the main prognostic factor. Neither glenoid deformation nor the lack of replacement appeared to have an effect on the final outcome. Deformation of the proximal end of the humerus may require use of a shorter stem which should be available at the time of the operation.