Rotator Cuff Tendinopathy

Degenerative or overload disease of one or more rotator cuff tendons (supraspinatus most often, then infraspinatus, subscapularis and teres minor), causing shoulder pain and weakness. It forms a spectrum from tendinopathy, through partial thickness tears, to full thickness tears.

• It is the commonest cause of shoulder pain, accounting for about 70 to 85% of cases in adults, and the commonest cause of pain in subacromial pain syndrome. Prevalence rises with age: tendon changes are present in about 20 to 25% of adults over 60 and in more than half of adults over 80, often without symptoms.
• Mechanisms: intrinsic degeneration (age, poor blood supply to the critical zone of the supraspinatus tendon about 1 cm from its insertion), extrinsic compression (acromial shape and spurs, thickened coracoacromial ligament, scapular dyskinesis), repetitive overhead activity, trauma, and calcific deposits.
• Risk factors: age above 40, overhead work and sport (painters, carpenters, swimmers, throwers, racquet sports), smoking, diabetes, hypercholesterolaemia, thyroid disease, a family history, corticosteroid or fluoroquinolone exposure, and obesity.
• About 70 to 80% of patients improve with well delivered conservative treatment over 6 to 12 months.

• Pain at the lateral and anterior shoulder, spreading to the lateral upper arm (deltoid insertion), worse with overhead and reaching activities, lifting, and lying on the shoulder at night, with night pain disturbing sleep. Weakness and loss of function increase with tears.
• Examination: a painful arc during abduction between 60 and 120 degrees, pain on resisted abduction and external rotation, a positive Neer test and Hawkins test (impingement), pain and weakness on the empty can (Jobe) test for the supraspinatus, weak external rotation at the side for the infraspinatus and teres minor, a positive lag sign for large tears, a positive drop arm sign, and a positive lift off or belly press test for the subscapularis. Passive range is usually full (limited in adhesive capsulitis).
• Differential diagnosis: adhesive capsulitis, glenohumeral osteoarthritis, calcific tendinitis, long head of biceps tendinopathy, acromioclavicular joint arthritis, glenohumeral instability and labral tear, cervical radiculopathy, suprascapular neuropathy, thoracic outlet syndrome, referred visceral pain (cardiac, diaphragmatic, gallbladder), Pancoast tumour, septic arthritis and fracture.
• Red flags: trauma with acute weakness (acute tear), fever and hot swollen joint, severe constant pain, neurological deficit, unexplained weight loss, history of cancer, and chest pain or breathlessness with arm pain.
• Complications: progression to full thickness tear, tear enlargement, fatty infiltration and muscle atrophy, rotator cuff arthropathy, adhesive capsulitis, and sleep and work disability.

• Clinical examination of the neck, shoulder and neurovascular function, with active and passive range and rotator cuff strength tests.
• X-ray (anteroposterior in the scapular plane, scapular Y and axillary views) shows the acromial shape, spurs, calcification, high riding humeral head (narrowing of the acromiohumeral distance below 7 mm suggests a large tear), and arthritis.
• Ultrasound is a first line imaging test and shows tendon thickening, hypoechoic change, partial and full thickness tears, calcification and bursal fluid, and guides injection. MRI (or MR arthrography) is the best test for tear size, retraction, muscle atrophy, labral lesions and when surgery is planned.
• Blood tests (CRP, ESR, full blood count, HbA1c) when inflammatory arthritis, infection or diabetes is suspected. Check the cervical spine and nerve function if radiculopathy is possible.

• Conservative treatment, first line for tendinopathy, partial tears and most degenerative full thickness tears in older or low demand patients, for 3 to 6 months:
  • Relative rest from overhead and aggravating activities, ergonomic changes, and early return to movement. Avoid a sling beyond a few days.
  • Paracetamol 1 g orally 6 hourly, ibuprofen 400 mg 8 hourly with food (or naproxen 500 mg 12 hourly, or diclofenac 50 mg 8 hourly) for 1 to 2 weeks, with gastroprotection in at risk patients, and topical diclofenac 1% gel 2 to 4 g 3 to 4 times daily. A short course of weak opioid for night pain only.
  • Ice 10 to 15 minutes after activity, and heat before exercise. Sleep with a pillow supporting the arm, and avoid lying on the affected side.
  • Physiotherapy for 12 weeks or more: posture and scapular stabilisation, progressive rotator cuff loading (isometric holds, then band resisted external and internal rotation, scaption, and eccentric work, 3 sets of 10 to 15, 3 to 4 times weekly), posterior capsule stretching, and graded return to overhead function.
• Subacromial corticosteroid injection for pain that limits rehabilitation after 4 to 6 weeks: triamcinolone acetonide 40 mg or methylprednisolone acetate 40 mg with lidocaine 1% 4 to 5 mL (or bupivacaine 0.25% 3 to 5 mL), preferably under ultrasound guidance. Relief lasts 2 to 12 weeks, and it can enable rehabilitation. Limit to 2 to 3 injections per year, avoid within 3 months before surgery (higher infection risk), and avoid in large tears awaiting repair. Risks: tendon weakening, skin atrophy and depigmentation, infection, and a rise in glucose for 3 to 5 days in diabetes.
• Other options: ultrasound guided needle lavage and extracorporeal shock wave therapy (3 weekly sessions) for calcific disease, platelet rich plasma (evidence mixed), and suprascapular nerve block for refractory night pain.
• Surgery:
  • Acute traumatic full thickness tear in an active patient: early repair within 3 to 6 weeks gives better results.
  • Degenerative full thickness tear with persistent pain and weakness after 3 to 6 months of failed conservative care: arthroscopic repair (single or double row, with suture anchors), with a sling for 4 to 6 weeks and gradual rehabilitation over 6 to 12 months. Healing is about 70 to 90% in small tears and lower in large tears (retear rates up to 20 to 40%), and age, smoking, diabetes and fatty atrophy reduce healing.
  • Partial tears with persistent symptoms: debridement, or repair if more than 50% of thickness.
  • Subacromial decompression and acromioplasty adds little to exercise alone in an intact cuff, so it is used in selected patients.
  • Massive irreparable tears: tendon transfer (latissimus dorsi, lower trapezius), superior capsular reconstruction, or reverse total shoulder arthroplasty (for older patients with cuff tear arthropathy and pseudoparalysis).
  • Prophylaxis: cefazolin 2 g IV once (3 g if above 120 kg).
• Special groups:
  • Diabetes: higher risk of stiffness and poor healing, so control glucose and monitor after injection.
  • Elderly: favour exercise, topical agents and fewer injections, and consider reverse arthroplasty only for severe disease.
  • Smokers: advise cessation, which improves tendon healing.
  • Pregnancy: physiotherapy, paracetamol and positioning. Avoid NSAIDs after 20 weeks and avoid steroid injection unless essential.
  • Anticoagulation: use ultrasound guidance with a fine needle and pressure for 5 to 10 minutes.
  • Renal impairment and gastrointestinal disease: avoid oral NSAIDs.
• Follow up: review at 6 weeks and 3 months. Refer to orthopaedics or sports medicine for suspected full thickness tear with weakness, acute traumatic tear, failure of 3 to 6 months of treatment, or diagnostic doubt.