Prospective clinical study of a novel biodegradable sub-acromial spacer in treatment of massive irreparable rotator cuff tears.

PURPOSE: The purposes of this prospective non-randomized study were to confirm the feasibility of the biodegradable sub-acromial spacer (InSpace™) implantation in patients with massive irreparable rotator cuff tear and to determine the safety profile and functional results 3 years post-implantation.

METHODS: Twenty patients were implanted with the InSpace™ device and assessed up to 3 years of post-implantation. Improvement in shoulder function was assessed using Constant score, while ease of use of the system was recorded by surgeons as were device-related adverse events.

RESULTS: Twenty patients were available for assessment. Implantation was performed arthroscopically in all patients, and a range of deployment time was 2-20 min. The mean total Constant score increased from 33.4 to 65.4 points at 3 years. There was an improvement of 6.4 points in subjective pain score which commenced at 1 week post-operatively and was sustained until 3 years of follow-up. Also activities of daily living and motions commenced improvement by 9.4 and 7.7 points, respectively. Improvement in power was only evident at 18 months of follow-up but was sustained at 3 years.

CONCLUSIONS: Arthroscopic deployment of a co-polymer biodegradable spacer (balloon) into the sub-acromial space for an irreparable rotator cuff tear was found to be low-risk and simple procedure associated with improvement in shoulder function and low rate of complications.

LEVEL OF EVIDENCE: IV; therapeutic case series.