Shoulder Stiffness — Adhesive Capsulitis

Adhesive capsulitis (frozen shoulder) is a common and disabling condition characterised by progressive pain and global restriction of glenohumeral joint movement, caused by fibrotic thickening and contracture of the shoulder capsule. It has an estimated prevalence of 2–5% in the general population, with a significantly higher incidence in diabetics (10–20%). Despite its familiar name, the pathophysiology is not primarily inflammatory but rather a fibroproliferative disorder akin to Dupuytren`s disease of the shoulder capsule.

• Incidence: 2–5% general population; peak incidence 40–65 years; female:male ratio approximately 3:2; bilateral in 6–30% (the contralateral shoulder is affected in a significant minority, usually sequentially)
• Risk factors: diabetes mellitus (most strongly associated — 10–20% of diabetics develop frozen shoulder; diabetics have a more severe and prolonged course, more frequent bilateral involvement, and worse response to manipulation); thyroid disease; Dupuytren`s disease (sharing similar fibroproliferative pathology); Parkinson`s disease; prolonged immobilisation; cardiac surgery; breast surgery and axillary node dissection
• Pathophysiology: synovial inflammation (early) → fibroblast proliferation → collagen deposition → capsular contracture → axillary fold obliteration and rotator interval contracture; the anterior capsule and rotator interval (between the supraspinatus and subscapularis) are the primary sites of contracture; capsular volume is dramatically reduced (from normal 28–35 mL to 5–10 mL)
• Classification: primary (idiopathic — no underlying cause); secondary (post-traumatic, post-surgical, post-immobilisation, systemic cause such as diabetes)

• Natural history: the majority of patients achieve satisfactory resolution of symptoms within 2–3 years without surgical intervention; however, approximately 15–20% of patients have persistent pain and motion restriction beyond 3 years; patients with diabetes have a longer course and more incomplete recovery; the "self-limiting" characterisation is not universal

• Symptoms: insidious onset of global shoulder pain (diffuse, poorly localised, often referred to the deltoid insertion); marked nocturnal pain (Stage 1); progressive global restriction of all shoulder movements; difficulty with activities of daily living (dressing, reaching overhead and behind back, seatbelt, bra strap)
• Key clinical finding: global restriction of passive and active glenohumeral movement in all planes — external rotation loss is typically the most severe (often to 0° or even internal rotation only); flexion, abduction, and internal rotation also restricted; the restriction is PASSIVE as well as active (differentiating from rotator cuff tear where passive movement may be preserved)
• External rotation (ER): tested with the elbow at the side; normal approximately 60–70°; in frozen shoulder, often <30° or absent; loss of passive ER is the hallmark finding
• Scapular compensation: as GHJ motion is lost, the scapula compensates with increased rotation — observe from behind; scapular dyskinesis (winging, premature elevation) indicates glenohumeral restriction
• Exclude secondary causes: assess for rotator cuff pathology, OA, infection, tumour, and referred pain from the cervical spine (spurling test, cervical ROM); MRI or USS if diagnosis uncertain

• Plain radiographs: AP and axillary shoulder; usually normal in primary frozen shoulder; exclude glenohumeral OA, calcific tendinitis, osteochondral lesion, and superior migration of the humeral head; periarticular osteopaenia may be seen in prolonged cases
• MRI shoulder: thickening of the rotator interval (between supraspinatus and subscapularis — the primary site of contracture), axillary pouch contracture, and capsular thickening are the characteristic findings; useful to exclude rotator cuff tears, labral pathology, and OA; not mandatory in typical clinical presentation
• Arthrogram: reduced joint volume (5–10 mL vs normal 28–35 mL) is pathognomonic; rarely performed for diagnosis but can confirm frozen shoulder when clinical diagnosis uncertain; used in hydrodilatation procedure
• Bloods: fasting glucose, HbA1c (undiagnosed diabetes), TFTs (thyroid disease) — all patients with frozen shoulder should have these checked as systemic association is common and may be the first presentation of diabetes

• Stage 1 (painful freezing): analgesia (NSAIDs, paracetamol); subacromial or glenohumeral corticosteroid injection — most effective in early Stage 1 for pain relief; physiotherapy (gentle pendulum exercises, pain-free ROM); avoid aggressive physiotherapy in the painful phase as this may worsen synovitis
• Corticosteroid injection: significant short-term benefit (6–12 weeks) for pain and early ROM; most effective in the painful freezing stage; multiple injections may be given (3 maximum — risk of tendon and skin atrophy, cartilage damage, and systemic effects in diabetics); effect is primarily on pain rather than long-term ROM restoration; USS-guided glenohumeral injection is more accurate than landmark-guided
• Hydrodilatation (hydrodistension): USS-guided distension arthrography — injection of saline (10–40 mL), local anaesthetic, and corticosteroid into the glenohumeral joint to disrupt the capsule and restore volume; evidence supports short-term benefit for pain and ROM; may be repeated; useful in Stage 1–2; relatively minimally invasive
• Stage 2 (frozen): physiotherapy with stretching exercises; home exercise programme; hydrodilatation; continue until natural resolution; the role of aggressive physiotherapy (beyond pain-free range) is controversial and not supported by evidence in this stage

• Surgical indications: failure of 6 months of structured non-operative management; persistent significant functional restriction; patient preference after full discussion of non-operative timeline
• Manipulation under anaesthesia (MUA): the most commonly performed procedure; performed under general anaesthesia or interscalene nerve block; the shoulder is progressively manipulated in flexion, abduction, ER, and IR to rupture the contracted capsule; immediate post-operative physiotherapy essential to maintain gained ROM; complications include humeral shaft fracture, rotator cuff tear, glenohumeral dislocation, brachial plexus injury, and labral tear; AVOID in patients with severe osteoporosis
• Arthroscopic capsular release: arthroscopic division of the contracted capsule — rotator interval, anterior capsule, and inferior axillary recess; under direct visualisation; avoids the blind force of MUA; can be combined with MUA; particularly useful in diabetics (who have a higher risk of fracture with MUA) and in cases of failure of MUA; allows assessment of glenohumeral joint at the same time
• Arthroscopic release vs MUA: no clear evidence of superiority of one over the other in most cases; arthroscopic release allows more precise capsulotomy and is safer in high-risk patients (osteoporosis, diabetes, post-surgical stiffness with scarring); MUA is faster and simpler; many surgeons combine both (MUA first, then arthroscopic assessment and targeted release of any remaining tight areas)
• Post-operative rehabilitation: intensive physiotherapy from day 1 is essential to prevent recurrence of contracture; interscalene nerve block (prolonged if catheter placed) facilitates early rehabilitation by providing analgesia; continuous passive motion (CPM) occasionally used

• Diabetic frozen shoulder: more severe, more bilateral, more prolonged, and more refractory than idiopathic frozen shoulder; responds less well to corticosteroid injection (also causes blood glucose elevation — warn diabetic patients); responds less well to MUA (higher fracture risk and higher recurrence); arthroscopic capsular release gives better long-term outcomes than MUA in diabetics; optimise glycaemic control before and after surgery; HbA1c should be checked and controlled before elective surgery
• Rotator cuff tear associated with MUA: a recognised complication; the risk is higher in older patients with pre-existing rotator cuff disease; clinical assessment of rotator cuff function post-MUA is important — failure to regain active elevation despite restored passive range suggests a new rotator cuff tear; MRI if suspected; repair if significant functional deficit
• Secondary frozen shoulder after arthroplasty: adhesive capsulitis can develop after shoulder arthroplasty, rotator cuff repair, or other shoulder surgery; treatment is more challenging; arthroscopic release preferred over MUA (risk of component loosening or periprosthetic fracture); ensure implant is well-fixed before MUA if this is planned
• Treating the rotator interval in arthroscopic release: the rotator interval is the primary site of contracture — release of the coracohumeral ligament and anterior rotator interval tissue is the most important step in restoring external rotation; this is performed first during arthroscopic release and alone may restore ER dramatically in early cases

• Three stages: Stage 1 painful freezing (3–9 months); Stage 2 frozen/stiff (3–12 months); Stage 3 thawing/resolution (6–24 months)
• Diabetes: strongest association — 10–20% of diabetics affected; worse prognosis, bilateral, refractory, higher surgical risk
• Key clinical finding: global PASSIVE restriction — ER loss most severe; distinguishes from rotator cuff tear (passive range preserved)
• Capsular volume: reduced from normal 28–35 mL to 5–10 mL — pathognomonic on arthrogram
• Check HbA1c and TFTs in all patients — frozen shoulder may be the first presentation of undiagnosed diabetes or thyroid disease
• Corticosteroid injection: most effective in Stage 1 for pain; USS-guided glenohumeral injection; maximum 3 injections; short-term benefit primarily
• Natural history: 85% resolve within 2–3 years; 15–20% have persistent restriction beyond 3 years; diabetics slower to resolve
• MUA complications: humeral fracture, rotator cuff tear, dislocation, BPI; avoid in severe osteoporosis; ensure immediate post-op physiotherapy
• Arthroscopic release preferred over MUA in: diabetics, post-surgical stiffness, osteoporosis, failed MUA; rotator interval release is the key step for restoring ER
• Hydrodilatation: USS-guided distension with saline + steroid; short-term benefit for pain and ROM; less invasive than surgery