Persistent and profound peripheral nerve injuries following reverse total shoulder arthroplasty

Background: Peripheral nerve injuries associated with reverse total shoulder arthroplasty (rTSA) are rarely reported and are often dismissed as neuropraxias, particularly in the setting of perioperative nerve blocks. The purpose of this study was to evaluate nerve injuries following rTSA to determine if there is a pattern of injury and to evaluate outcomes of patients who sustain an intraoperative nerve injury. Methods: A retrospective review was performed identifying patients who underwent rTSA and had a concomitant major nerve injury who were referred to a multidisciplinary peripheral nerve injury clinic. Demographic data, preoperative nerve block use, physical examination, electrodiagnostic studies, injury pattern, and time from injury to referral was collected. Radiographs, Quick Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH) score, and outcomes surveys were obtained at final follow-up. Results: Twenty-two patients were identified with postoperative nerve injuries. Average time from injury to referral was 9.0 months, with 18.8 months’ follow-up. Eight patients had undergone prior shoulder surgery, and 11 patients had prior shoulder trauma. Injury patterns were variable and involved diffuse pan-plexopathies with severity localized to the posterior and medial cords (11), the upper trunk (5), lateral cord (2), and axillary nerve (4). The average postoperative acromiohumeral distance (AHD) was 3.7 cm, with an average change of 2.9 cm. The average postoperative lateral humeral offset (LHO) was 1.1 cm, with an average change of 0.2 cm. Seventeen patients were confirmed to have undergone preoperative nerve blocks, which were initially attributed as the etiology of nerve injury. Eighteen patients were initially treated with observation: 11 experienced residual debilitating neuropathic pain and/or disability, and 7 had substantial improvement. One patient underwent nerve transfers, whereas the others underwent procedures for hand dysfunction improvement. The average QuickDASH score was 53.5 at average of 4 years post rTSA. Conclusions: Although uncommon, permanent peripheral nerve injuries following rTSA do occur with debilitating effects. Preoperative regional blocks were used in most cases, but none of the blocks could be directly attributed to the nerve injuries. Nerve injuries were likely secondary to traction at the time of arthroplasty and/or substantial distalization and lateralization of the implants. Patients with medial cord injuries had the most debilitating loss of hand function. Surgeons should be cognizant of these injuries and make a timely referral to a peripheral nerve specialist.