Abstract
We evaluated the results of Cementless Surface Replacement Arthroplasty (CSRA) of the shoulder in 67 patients with advanced glenohumeral destruction who have an intact rotator cuff.
Between november 2002 and december 2008, 70 CSRA (32 Copeland/ Biomet and 38 SMRR/ Lima) were implanted in 67 patients. A deltopectoral approach was used in 34 cases and an anterosuperior approach in 36 cases. Patients were assessed using Constant score, a patient satisfaction score and a detailed radiographic analysis. The mean follow up was 3.4 years (range 1 to 7.5 years).
The mean Constant score improved preoperatively from 17.6 points (range 2–55) to an average postoperative score of 66.1 (range 13–91). The pain score improved from 1.13 points (range 0–6) to 12.3 points (range 3–15). The forward flexion and external rotation improved from 71° (range 20 to 140) and 0° (range −40 to +45) to 143° (range 60 to180) and 34.4° (range −20 to +60) respectively.
Complications included: 1 subscapularis detachment, 5 secondary rotator cuff tear, 1sepsis, 3 patients with shoulder stiffness.
No shift in implant position was observed. 11 humeral components developed radiolucencies at the prosthesis-bone interface. The radiographic analysis involved a system of dividing the prosthesis/bone interface into 5 zones.
The best clinical results were significantly achieved in patients with necrosis compared with osteoarthritis (Constant Score, ant. elevation, ext. Rotation).
Using regression analysis we found that changes in the head-shaft angle position of the implant (valgus/varus placement of the CSRA) significantly predicted the age and sex adjusted Constant score. When the inclination angle of the humeral head decreases, the adjusted Constant score increases. In the same model, we also found that the lateral offset of the humerus significantly predicted the adjusted Constant score. When the lateral offset of the humerus decreases, the adjusted Constant score increases.
The medialization of the glenoid significantly and negatively predicted the Constant score.
Conclusion
CSRA of the shoulder outcomes have been comparable with those of stemmed arthroplasties. Radiolucent lines occur with follow up and most of the time located in the S1 area. Glenoid wear and humeral head lateralization negatively impact the clinical score. Cementless Shoulder resurfacing is a viable alternative to conventional shoulder arthroplasty.
