The effect of glenohumeral osteoarthritis on the outcome of isolated operatively treated supraspinatus tears

Background Rotator cuff tear is considered to be a common source of shoulder pain and dysfunction. Osteoarthritis of the glenohumeral joint (OAG) may coexist with rotator cuff tear, especially in elderly patients. The aim of the study was to evaluate the effect of associated OAG on the treatment outcome of rotator cuff repair. Methods A total of 85 consecutive shoulders with an arthroscopically repaired isolated full-thickness supraspinatus tendon tear in males were included in this study. The grade of OAG was estimated preoperatively from shoulder radiographs using the Kellgren–Lawrence (K–L) classification, and peroperatively using the Outerbridge classification. Supraspinatus tendon tear was re-inserted anatomically to the native footprint in all cases. The Constant score was used as an outcome measure and was measured preoperatively and 1 year after the operation. The effect of OAG on the Constant score was analyzed statistically. Results 82 shoulders (96.5 %) were available for the 1-year follow-up. Preoperative OAG was detected in 22/82 patients (26.8 %). Any OAG above K–L grade 0 was associated with a lower Constant score preoperatively [49.9 (SD 17.6) vs. 60.1 (SD 16.7) ( p = 0.0185)] and also at the 1-year follow-up [73.9 (SD 17.5) vs. 82.8 (SD 10.9) ( p = 0.0074)]. 16/60 patients (26.7 %) with K–L grade 0 radiographs had peroperatively detected OAG. Furthermore, any peroperatively detected OAG was associated with a lower Constant score preoperatively [53.2 (SD 19.0) vs. 60.9 (SD 15.2) ( p = 0.0445)] and at the 1-year follow-up 76.8 [(SD 14.8) vs. 83.5 (SD 11.4) ( p = 0.0223)]. Conclusion OAG is a relatively common finding in operated supraspinatus tear patients. Pre- and peroperatively detected OAG during rotator cuff reconstruction is predictive for lower pre- and postoperative Constant scores.