One hundred and eighty-four patients with posterosuperior massive rotator cuff tears were randomized to receive either the InSpace biodegradable balloon spacer implant (n=93) or partial rotator cuff repair (n=91). The primary outcome of this trial was to assess the American Shoulder and Elbow Society (ASES) score at 24 months. The secondary outcomes of this trial were to assess Western Ontario Rotator Cuff (WORC), Constant-Murley shoulder score, pain scores using a Visual Analog Scale (VAS), quality of life using EuroQol-5 Dimensions-5 Level, and active range of motion at 10 days, 6 weeks, 3, 6, 12, and 24 months. This trial's results showed that the InSpace implant outcomes were comparable to the partial repair group at 6 weeks, 12 months and 24 months in regard to ASES scores. The balloon implant group also had significantly lower operative time and earlier recovery.