Secondary rotator cuff dysfunction following total shoulder arthroplasty for primary glenohumeral osteoarthritis: results of a multicenter study with more than five years of follow-up.

BACKGROUND: Secondary rotator cuff dysfunction is a recognized complication following shoulder arthroplasty. We hypothesized that the rate of secondary rotator cuff dysfunction would increase with follow-up and result in less satisfactory clinical and radiographic outcomes. Our aim was to investigate the rate of secondary rotator cuff dysfunction following shoulder arthroplasty for primary osteoarthritis and identify factors associated with the dysfunction.
METHODS: Between 1991 and 2003, in ten European centers, 704 total shoulder arthroplasties were performed for primary glenohumeral osteoarthritis. Complete radiographic and clinical follow-up of more than five years was available for 518 shoulders. The diagnosis of secondary rotator cuff dysfunction was made when moderate or severe superior subluxation of the prosthetic humeral head was present on radiographs. Multivariate logistic regression identified factors associated with the development of rotator cuff dysfunction. Kaplan-Meier survivorship analysis was performed, with the end point being secondary rotator cuff failure. Clinical outcome was assessed with use of the Constant score, a subjective assessment of the shoulder, and an evaluation of shoulder motion.
RESULTS: At an average of 103.6 months (range, sixty to 219 months) after shoulder arthroplasty, the rate of secondary rotator cuff dysfunction was 16.8%. Survivorship free of secondary cuff dysfunction was 100% at five years, 84% at ten years, and 45% at fifteen years. Duration of follow-up (p < 0.0001), implantation of the glenoid implant with superior tilt (p < 0.001), and fatty infiltration of the infraspinatus muscle (p < 0.05) were risk factors for the development of secondary cuff dysfunction. Patients with secondary rotator cuff dysfunction had significantly worse clinical outcomes (Constant score, subjective assessment, and range of motion; p < 0.0001) and radiographic results (radiolucent line score, radiographic loosening, glenoid component migration; p < 0.0001).
CONCLUSIONS: In this study, rates of secondary rotator cuff dysfunction with moderate or severe superior subluxation of the prosthetic humeral head increased with the duration of follow-up and significantly influenced the clinical and radiographic outcome of total shoulder arthroplasty performed for primary glenohumeral osteoarthritis. Preoperative fatty infiltration of the infraspinatus muscle and implantation of the glenoid component with superior tilt were prognostic factors.