The concept of a new developed cup arthroplasty (Durom-Cup) is the replacement of the destroyed joint surface with minimal bone resection. In cases of additional cuff arthropathy the cup can be placed in a more valgic position to articulate with the glenoid and the acromion. The aim of this prospective study was to evaluate the results of this surface replacement as a hemiarthroplasty in rheumatoid arthritis with and without cuff arthropathy.
35 Durom-Cups of 29 patients (23 woman, 6 men) with rheumatoid arthritis were evaluated preoperatively and every 3 months postoperatively. 7 of these shoulders additionally had cuff arthropathy. The average age was 61. 6 ± 11. 8 years and the average follow-up 33. 4 ± 11. 8 months. The Constant-Score and SAS-function-Score were used and the cups were examined radiologically.
In rheumatic shoulders without cuff arthropathy the Constant-Score increased from 20. 6 ± 9. 5 points preoperatively to 47. 1 ± 14. 8 points 3 months postoperatively, to 47. 4 ± 13. 7 points 6 months, and to 56. 3 ± 8. 8 points 9 months postoperatively. During further follow-up it increased slightly and was 59. 5 ± 10. 1 points 12 months, 61. 8 ± 11. 3 points 18 months and 64. 6 ± 14. 8 points 24 months postoperatively. In shoulders with cuff arthropathy the Constant-Score increased from 17. 6 ± 8. 2 points preoperatively to 45. 0 ± 6. 4 points 3 months postoperatively, to 45. 5 ± 8. 5 points 6 months, and to 51. 5 ± 838 points 9 months postoperatively. At this level the Constant-Score stayed during further follow-up and was 54. 1 ± 10. 5 points 12 months, 56. 3 ± 9. 8 points 18 months, and 56. 1 ± 11. 6 points 24 months postoperatively. No complication, component loosening, or changes of cup position were observed.
The results of the Durom-Cup are encouraging. In shoulders with additional cuff arthropathy the limited goal criteria were reached always. Therefore cup arthroplasty is a good alternative other kinds of shoulder endoprostheses in rheumatic shoulders with and without cuff arthropathy.
