Is the Subacromial Biodegradable Spacer “Reversible”?

Introduction: The management of patients with irreparable rotator cuff tears remains a challenge. Recently the subacromial biodegradable spacer (SBS) has been shown to be an effective treatment option in this group of patients. We have been using the SBS in our practice since 2009 with favorable, long lasting outcome in the majority of patients. Reverse shoulder arthroplasty (RSA) should be a viable salvage procedure in case non-arthroplasty solutions for the treatment of irreparable rotator cuff fail. The goal of our study was to evaluate the functional outcome, radiologic outcome and satisfaction in patients who were treated with RSA for failed SBS.

Methods: Six patients, with a mean follow-up of 30 months (range, 18-48) after RSA, were evaluated clinically with the Constant-Murley score, patient satisfaction and pain relief scores. The fixation of the glenoid and humeral components, subsidence and notching were evaluated on radiographs. The indications RSA were pain and functional deterioration.

Results: There were no intra or peri-operative complications related to the previous surgery, no adhesions or excessive fibrous tissue. The mean Constant score improved from 17 to 67. The mean patient satisfaction score improved from 2.7/10 to 8.5/10 and mean pain score improved from 1/15 to 12.5/15. We found an overall improvement in active forward flexion from 53° to 145°, external rotation from 20° to 45°, and internal rotation from 19° to 65°. No humeral loosening, subsidence or glenoid notching were observed.

Conclusions: Reverse arthroplasty is a valuable solution for patients with failed SBS insertion in short term follow up. The improvements in patient satisfaction, pain, clinical outcome as well as the radiographic results seem to be comparable with those of other studies reporting on the outcome of primary RSA for massive cuff tears.