Suprascapular Neuropathy Associated with Massive Rotator Cuff Tears: a Rationale for Arthroscopic Rotator Cuff Repair

INTRODUCTION Massive rotator cuff tears may be present in patients with minimal pain and good function, or in patients with significant pain and disability.5,6,14,26 In the latter case, arthroscopic repair, either partial or complete, has been demonstrated to improve function.3,11,20,21 The mechanism of recovery is believed to be associated with an improved rotator cuff function due to at least partial healing of the posterior portion of the tendon repair. 6-8,11,16,18,22 However, retear after repair of a massive tear has been shown to be common.13,17 Recently, it has been suggested that a consequence of tendon tearing and retraction is traction on the suprascapular nerve (SSN) with the result being suprascapular nerve dysfunction (SSND) presenting as pain and weakness (Figs. 1A and B).1,2 The anatomy of the suprascapular nerve has been well described by others who have emphasized the relatively fixed position of the nerve as it passes beneath the transverse scapular ligament, thus making it especially prone to injury.4,23-25,2729,31 In addition, previous studies have demonstrated the limits of lateral advancement of the rotator cuff before placing these neurovascular structures at risk during operative repair.31 It has been suggested that improved pain and function despite radiographic evidence of a failed rotator cuff repair may be the result of complete or partial decompression of a tethered suprascapular nerve1,2 In a prospective series of eight consecutive patients with massive rotator cuff tears, Albritton and coworkers reported that all patients had evidence of suprascapular nerve dysfunction with severe limitation of active motion and pain.2 Half of the patients elected for partial arthroscopic rotator cuff repair with significant improvement in function at an average sixteen month followup. Vad examined the prevalence of peripheral neurologic injuries in twenty-five patients with full-thickness tears of the rotator cuff associated with shoulder muscle atrophy. He noted a 28% prevalence of peripheral neuropathy, primarily involving the axillary and suprascapular nerves in patients with full-thickness rotator cuff tears.30 The purpose of our study was to test two hypotheses: Hypothesis #1: SSND is not uncommonly associated with massive rotator cuff tears. Hypothesis #2: Arthroscopic repair of massive rotator cuff tear in patients with SSND will result in improved pain and function which will correlate with recovery of SSND.