InSpace Implant Compared with Partial Repair for the Treatment of Full-Thickness Massive Rotator Cuff Tears

These authors evaluated the outcomes of a subacromial balloon spacer (InSpace; Stryker) compared with arthroscopic partial repair in patients with irreparable, posterosuperior massive rotator cuff tears. Twenty sites randomized 184 patients: 93 to the InSpace group and 91 to the partial repair group.

Included patients were 40 years of age or older with symptomatic, irreparable, posterosuperior, massive rotator cuff tears and an intact subscapularis who had failed nonoperative management.

Intraoperative eligibility criteria were confirmed during the arthroscopic surgery. Subjects were included if the posterosuperior, massive rotator cuff tear was amenable to partial repair (adequate tissue quality to restore the force couple) but could not be completely repaired, the subscapularis was intact, and severe glenohumeral arthritis was not present. Eligible subjects were electronically randomized intraoperatively 1:1 to either receive the InSpace implant without partial repair (the treatment group) or undergo partial repair (the control group). Patients randomized to partial repair underwent suture anchor

repair (the best possible repair as determined by the operating surgeon) of the posterosuperior rotator cuff.

Concomitant procedures were frequently performed in both groups.

The operative time was significantly shorter in the InSpace group that for the group having partial rotator cuff repair.

Subjects were blinded to their treatment assignment throughout the study. The rehabilitation program was the same for both groups.

Clinical outcome data were collected at baseline through a 24-month follow-up. The primary outcome measure was improvement in the American Shoulder and Elbow Surgeons (ASES) scores. Significant and clinically relevant improvements in the ASES score from baseline were noted in both groups at Month 12 and were maintained at Month 24. Overall, 83% of patients in the InSpace group and 81% of patients in the partial repair group achieved the ASES minimally clinically important difference threshold, and 82% of patients in the InSpace group and 79% of patients in the partial repair group achieved the substantial clinical benefit threshold.

The shoulder physical examination was conducted by an investigator not blinded to treatment group.

No device-related surgical complications were noted. 4 reoperations after InSpace implantation and 3 reoperations after partial repair were required.

The authors concluded that "the InSpace implant demonstrated functional and patient reported outcomes that were comparable with those of partial repair for the treatment of irreparable, posterosuperior, massive rotator cuff tears in shoulders with an intact subscapularis by month 12, with durable benefit maintained up to month 24. "

Comment: This study comparing the InSpace balloon to partial repair can be compared to another recent study (see this link) comparing the InSpace balloon combined with debridement to debridement alone; it found that debridement alone yielded superior outcomes to debridement combined with the balloon.

Further studies will elucidate whether the subacromial balloon offers clinically significantly better outcomes - i.e. an added benefit that exceeds the minimally important clinical difference - than other treatment methods for the treatment of massive irreparable posterior rotator cuff tears.

In patients with retained active elevation, the smooth and move procedure can produce substantial and durable improvement in comfort and function for patients with massive irreparable rotator cuff tears as well as for patients with failed rotator cuff surgery (see this link). Patients having this procedure are encouraged to return to their activities as soon as possible after surgery.

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