Adhesive Capsulitis

Adhesive capsulitis (frozen shoulder) is a condition of pain and progressive restriction of active and passive glenohumeral motion, from synovitis and fibrosis of the capsule, mainly in the rotator interval, coracohumeral ligament and axillary recess. It affects 2 to 5% of the general population, mostly aged 40 to 60, and women more than men.

The primary (idiopathic) form is associated with diabetes (prevalence 10 to 20% of diabetics, with more severe and longer disease), thyroid disease, stroke, cardiac disease, Dupuytren contracture and Parkinson disease. Secondary causes include shoulder surgery, fracture, rotator cuff injury and prolonged immobilization.

Course is self-limiting over 1 to 3 years, in three phases: freezing (painful, 2 to 9 months), frozen (stiff, 4 to 12 months) and thawing (recovery, 5 to 24 months). Up to half have residual limitation. The other shoulder is affected in 20 to 30%, usually within 5 years.

• Gradual onset of shoulder pain, worse at night and on lying on the shoulder
• Progressive stiffness: loss of external rotation greater than 50% compared with the other side, then abduction and internal rotation
• Equal active and passive motion loss (capsular pattern), and a firm endpoint
• Difficulty dressing, reaching behind the back and combing hair
• Red flags: age under 40, bilateral onset, no pain with stiffness, neurological signs, fever, weight loss, unrelenting night pain (tumor), a recent fall or seizure (locked posterior dislocation)

• Clinical diagnosis: loss of passive external rotation, with normal radiographs.
• Radiographs (anteroposterior in internal and external rotation, scapular Y and axillary): exclude glenohumeral arthritis, calcific tendinitis, locked posterior dislocation, and tumor. Radiographs are normal in adhesive capsulitis.
• Ultrasound or MRI arthrography: a thickened coracohumeral ligament (over 3 mm), thickened axillary recess capsule (over 4 mm), and rotator interval obliteration. MRI is used if other pathology is suspected.
• Blood tests: fasting glucose and HbA1c, thyroid stimulating hormone, and lipids.

Differentials: rotator cuff tear, glenohumeral osteoarthritis, calcific tendinitis, locked posterior dislocation, cervical radiculopathy, subacromial pain, neoplasm, complex regional pain syndrome.

• Education and analgesia: reassurance about the self-limiting course. Paracetamol 1 g orally every 6 hours (maximum 4 g/day) and naproxen 500 mg orally twice daily with food for up to 2 to 4 weeks (avoid in peptic ulcer disease, renal impairment, heart failure and anticoagulation).
• Intra articular corticosteroid (most effective in the painful phase): triamcinolone acetonide 40 mg with lidocaine 1% 5 mL into the glenohumeral joint by the posterior approach under ultrasound guidance. Repeat once after 6 weeks if needed. In diabetics monitor glucose for 3 to 5 days.
• Hydrodilatation: injection of triamcinolone 40 mg, lidocaine 1% 5 mL and normal saline to a total of 30 to 40 mL to distend the capsule.
• Physiotherapy: gentle stretching within pain limits, 3 to 4 times daily, with pendulum exercises and capsular stretching (external rotation, forward flexion, cross body reach). Avoid aggressive stretching in the painful phase.
• Suprascapular nerve block with bupivacaine 0.25% 10 mL for refractory pain.
• Surgery after 6 to 12 months of failed treatment:
  • Arthroscopic capsular release (rotator interval, anterior, inferior and posterior capsule) with or without manipulation under interscalene block.
  • Manipulation under anesthesia carries a risk of humeral fracture (especially in osteoporosis), labral tear and rotator cuff injury.
  • Cefazolin 2 g IV before incision.
  • Immediate postoperative physiotherapy, with an interscalene catheter for 48 hours.
• Complications: recurrent stiffness, fracture, axillary nerve injury and cuff tear.

Follow up every 4 to 6 weeks. Counsel on optimal diabetes control and on contralateral shoulder risk.