Shoulder Rotator Cuff Arthropathy
Rotator Cuff Arthropathy is a pattern of degenerative joint disease of the shoulder, which results from chronic large rotator cuff tearing. The impact of a chronic rotator cuff tear of this magnitude is abnormal wear of the shoulder (glenohumeral) joint.
Chronic rotator cuff insufficiency results in cartilage damage, superior migration of the humeral head, and subchondral osteoporosis. It most commonly occurs in the 7th decade of life, and affects females more than males.
Hamada Classification of Rotator Cuff Arthropathy
- Grade 1: Acromiohumeral interval ≥6 mm
- Grade 2: Acromiohumeral ≤5mm
- Grade 3: Acromiohumeral ≤5mm, with acetabularization of acromion
- Grade 4a: Glenohumeral arthritis without acetabularization, AHI < 7 mm
- Grade 4b: Glenohumeral arthritis with acetabularization, AHI ≤5 mm
- Grade 5: Humeral head collapse
Physical Examination and Work-up
On examination, patients often limitations in active and passive range of motion, as well as grinding/crepitus during motion. There may be atrophy of the supraspinatus and infraspinatus muscles noted and prominence of the humeral head anteriorly.
External Rotation Lag Sign: the examiner passively places the shoulder in external rotation with the elbow at 90 degrees. If the patient cannot maintain the position, this finding is consistent with a massive infraspinatus tear.
X-rays are utilized to classify the arthropathy with the Hamada Classification system. X-rays also demonstrate the presence of osteophytes and, possibly, the “snowcap sign” due to subchondral sclerosis. MRI is not needed to make a diagnosis if the humeral head is demonstrating anterosuperior escape, however, it will help characterize the fatty infiltration of the rotator cuff.
Management of Rotator Cuff Arthropathy
Physical therapy, activity modification, NSAIDs and injection are the mainstays of first line treatment. If non-operative treatment fails, reverse total shoulder arthroplasty (RTSA) is considered. RTSA requires a well-functioning deltoid muscle and good bone stock. The deltoid is required to assist the glenohumeral joint in acting like a fulcrum during shoulder elevation. Post-operative rehabilitation is closely monitored and guided with criterion-based advancement based on regular exercise testing intervals at the COSMO Fit Lab.