Concurrent rotator cuff tear and axillary nerve palsy associated with anterior dislocation of the shoulder and large glenoid rim fracture: a "terrible tetrad".

We present a case of concurrent rotator cuff tear and axillary nerve palsy resulting from anterior dislocation of the shoulder and a large glenoid rim fracture-a "terrible tetrad." A 61-year-old woman fell on her right shoulder. Radiographs showed anterior dislocation of the shoulder with a glenoid rim fracture, and an MRI two months after injury revealed a rotator cuff tear. Upon referral to our hospital, physical and electrophysiological examinations revealed axillary nerve palsy. The axillary nerve palsy was incomplete and recovering, and displacement of the glenoid rim fracture was minimal and already united; therefore, we surgically repaired only the rotator cuff tear three months after injury. The patient recovered satisfactorily following the operation. In patients whose axillary nerve palsy is recovering, surgeons should consider operating on rotator cuff tears in an attempt to prevent rotator cuff degeneration.