Arthroscopic bursectomy less effective in the degenerative shoulder with chronic subacromial pain

BACKGROUND: Varying results after surgery in patients with subacromial pain syndrome (SAPS) have raised the question on whether there is a subgroup of patients that can benefit from surgery. Therefore, we aimed to identify preoperative and peroperative factors associated with a favorable patient-reported outcome after arthroscopic bursectomy in patients with SAPS. METHODS: Patients with chronic SAPS who underwent arthroscopic bursectomy after failed conservative management were included (n = 94). Patients were evaluated at the baseline, and 2 weeks, 8 weeks, 6 months, and 1 year after surgery. The primary outcome was the Western Ontario Rotator Cuff index (WORC) score one year after surgery. The secondary outcome measure was a visual analog scale for pain. Mixed model analyses were used to identify prognostic factors. RESULTS: The mean WORC (mean difference 39%, 95% confidence interval (CI) 32.8–45.3, P < .001) and visual analog scale pain scores (mean difference 41 mm points, 95% CI 3.37–4.88, P < .001) significantly improved one year after surgery. Nineteen patients (20%) developed a postoperative frozen shoulder. A longer duration of preoperative complaints and the peroperative identification of degenerative glenoid cartilage were associated with significantly worse WORC scores, with −0.086% per month (95% CI −0.156 to −0.016, P = .016) and −20% (95% CI −39.4 to −1.26, P = .037), respectively. CONCLUSION: We identified demographic and clinical factors that predict the course after arthroscopic subacromial bursectomy. We found that arthroscopic bursectomy is less effective in patients with SAPS with a degenerative shoulder. This finding suggests that an improved treatment effect of arthroscopic subacromial bursectomy can be expected in patients with chronic SAPS if intra-articular pathologies such as glenohumeral osteoarthritis are sufficiently excluded.