01OverviewDefinition, clinical context and the essential points that orientate the chapter.
Adhesive capsulitis is a painful fibrosing disorder of the glenohumeral capsule, commonly called frozen shoulder. Typical onset is gradual in a middle-aged adult, with night pain and difficulty fastening clothing, reaching a back pocket, washing hair or putting on a coat. Ask what became restricted first and whether an injury produced immediate loss. Establish diabetes, thyroid disease, previous surgery, stroke, prolonged sling use, cancer, infection exposure and bilateral symptoms. The natural history is prolonged and variable; promising a fixed recovery date undermines trust when improvement takes one to three years.
Examination must isolate the glenohumeral joint from scapulothoracic compensation. Observe scapular movement, then compare active and passive elevation, external rotation with elbow at the side, abduction and internal rotation with the opposite shoulder. A firm painful endpoint and marked passive external-rotation loss support capsular contracture. Inspect for wasting or swelling, palpate focal structures, assess cuff power within available range and examine cervical neurology. Pain alone can cause guarding, so repeat gently and avoid forcing a highly irritable shoulder.
Clinical diagnosis is appropriate when the history and capsular pattern are convincing and red flags are absent. Plain radiography is the useful exclusion test when arthritis, calcific disease, previous trauma or atypical progression is plausible. A normal radiograph is compatible with frozen shoulder. Ultrasound may show coexisting cuff disease but does not establish the diagnosis. MRI is reserved for a specific alternative, unexplained weakness, tumour concern or surgical planning rather than ordered reflexively.
Explain the phases without presenting rigid boundaries. During pain-predominant disease, sleep support, safe analgesia and gentle movement within tolerance matter more than aggressive stretching. As irritability falls, physiotherapy can progress capsular range, active control and strength. Home practice should be frequent enough to maintain gains but not so forceful that severe pain persists into the next day. Set functional markers such as hand-behind-back level, external rotation, sleep and dressing instead of chasing range measurements alone.
Intra-articular corticosteroid is most useful as short-term anti-inflammatory treatment in the painful stage. Accurate glenohumeral placement, often image guided according to local service, improves confidence that the intended compartment was treated. Discuss temporary pain flare, facial flushing, skin change, bleeding, rare infection and glucose rise. Arrange extra glucose checks for several days in diabetes. Injection does not instantly reverse fibrosis; its value is a quieter window for sleep and movement.
Hydrodilatation distends the contracted capsule with fluid, usually with local anaesthetic and corticosteroid, and may improve pain and movement in selected patients. Evidence and technique vary, so it is a specialist or commissioned-pathway choice rather than a universal gold standard. Persistent disabling restriction may lead to manipulation under anaesthesia or arthroscopic capsular release. Both require informed discussion and immediate structured rehabilitation to preserve movement, with particular caution around osteoporosis, previous instability and medical fitness.
Distinguish the condition from glenohumeral osteoarthritis. Both restrict passive range, but deep mechanical pain, crepitus and radiographic cartilage loss favour arthritis. Conversely, preserved passive movement with painful weakness suggests cuff disease. Fever and an acutely hot joint require aspiration for infection; acute post-traumatic restriction requires imaging. Bilateral shoulder and hip-girdle stiffness in an older adult suggests polymyalgia rheumatica, not bilateral frozen shoulders by default.
Adapt treatment to context. Diabetes predicts a more resistant course and makes injection-related hyperglycaemia relevant, but does not preclude evidence-based care. Older patients need fracture risk considered before forceful procedures. Anticoagulation requires an individual procedural bleeding plan; do not instruct unsupervised interruption. In pregnancy, prioritise education and physiotherapy, choose compatible analgesia and avoid systemic NSAIDs from 20 weeks unless specifically required, with complete avoidance late in gestation.
Key points
- The defining examination feature is loss of both active and passive glenohumeral movement, with passive external rotation at the side disproportionately restricted.
- Pain commonly precedes dominant stiffness: a painful phase may progress to a stiff phase and then slow recovery, although individual trajectories overlap rather than follow a perfect timetable.
- Diabetes is the strongest common association; ask about thyroid disease, previous shoulder immobilisation, trauma and surgery, but do not order broad screening without clinical reason.
- First-line investigation is a careful movement examination; obtain plain radiographs when needed to exclude glenohumeral arthritis, fracture, dislocation, calcification or destructive disease.
- MRI is not the gold-standard confirmation for a typical case because adhesive capsulitis is a clinical diagnosis and scanning may reveal distracting age-related cuff abnormalities.
- First-line management combines explanation, analgesia and physiotherapy matched to irritability: gentle tolerated movement during severe pain, then progressive range and strengthening as pain recedes.
- An image-guided or anatomically accurate intra-articular corticosteroid injection can improve short-term pain and function, particularly early, and should be linked to a rehabilitation goal.
- Escalate persistent major restriction after adequate non-operative care for specialist consideration of hydrodilatation, manipulation under anaesthesia or arthroscopic capsular release.
02AetiologyUnderlying causes, associations and risk factors, with why each one matters.
Primary disease
Many cases arise without a preceding structural lesion, typically in midlife, and reflect an individual fibrotic response rather than damage from ordinary movement.
Diabetes association
Diabetes substantially increases risk, bilateral involvement and persistent restriction; duration and glycaemic burden may influence severity even though correcting glucose does not immediately reverse fibrosis.
Endocrine and systemic associations
Thyroid disease, dyslipidaemia and some neurological disorders occur more often among affected people and may justify targeted assessment when history suggests them.
Secondary immobilisation
Pain, trauma, breast surgery, cardiac surgery or prolonged arm protection can precede capsular inflammation and shortening, particularly when active shoulder movement is delayed.
03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.
- 1Early synovial inflammation
An initially painful inflammatory phase affects the rotator interval and capsule, producing intense night pain and guarding before fixed stiffness dominates.
- 2Fibroblast and myofibroblast activity
Collagen deposition and contractile cellular activity thicken the coracohumeral ligament and capsule, reducing joint volume and external rotation.
- 3Capsular pattern
Contracture restricts passive external rotation most recognisably, then abduction and internal rotation, distinguishing true joint stiffness from isolated weakness or voluntary protection.
- 4Slow remodelling
Inflammation eventually declines and tissue remodels, but improvement often takes many months and residual restriction can persist, especially with diabetes or severe initial loss.
04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.
Progressive night pain and pain at the end of movement may dominate before the patient appreciates the extent of fixed restriction.
Restriction when the examiner rotates the relaxed arm with the elbow by the side is the most useful high-yield sign of the capsular pattern.
Hair care, fastening a bra, reaching a back pocket, dressing and overhead tasks become difficult as several planes contract.
The scapula rotates early to compensate for a stiff glenohumeral joint, so apparent elevation may overestimate true joint motion.
A history of diabetes increases probability, bilateral disease and persistence, while also changing steroid-injection counselling and monitoring.
Focal weakness, preserved passive rotation, neurological findings, systemic illness or radiographic joint destruction argues against uncomplicated adhesive capsulitis.
05InvestigationsWhat to request, why it matters and how to interpret it.
Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.
- 01
First-line active and passive range examinationFirst stepFirst line - Why
- Demonstrate true glenohumeral capsular restriction and separate it from pain-limited active weakness.
- Interpretation and limitations
- Marked passive external-rotation loss with restriction in other planes supports adhesive capsulitis after urgent alternatives are excluded.
- 02
Plain shoulder radiographs - Why
- Exclude arthritis, fracture, unreduced dislocation, calcific deposit and destructive bone disease when presentation is stiff or atypical.
- Interpretation and limitations
- Normal joint space and contour support the clinical diagnosis; radiographic arthritis redirects management even if capsular stiffness coexists.
- 03
Targeted glucose or HbA1c - Why
- Identify or review diabetes when symptoms, risk factors or monitoring history make testing clinically appropriate.
- Interpretation and limitations
- Diabetes association informs prognosis and injection safety, but a raised result does not prove that shoulder symptoms are capsulitis.
- 04
Targeted thyroid testing - Why
- Assess suspected thyroid dysfunction rather than screen every patient indiscriminately.
- Interpretation and limitations
- Abnormal thyroid status may be associated and merits treatment on its own criteria; correction does not provide immediate capsular release.
- 05
Ultrasound or MRI for a competing question - Why
- Investigate substantial weakness, tumour concern, unusual trauma or anatomy needed for intervention.
- Interpretation and limitations
- Imaging signs of capsulitis are not required for routine diagnosis, and incidental cuff abnormalities must be correlated clinically.
- 06
Urgent aspiration when infection suspected - Why
- Obtain synovial cell count, Gram stain, culture and crystals from an acutely hot painful joint.
- Interpretation and limitations
- Do not allow normal blood inflammatory markers or a presumptive frozen-shoulder label to delay source control and antimicrobial care.
06Differential diagnosisRealistic alternatives and the features that help distinguish them.
Glenohumeral osteoarthritis
Both conditions restrict passive movement, but arthritis often adds crepitus and radiographic joint-space narrowing, osteophytes or humeral-head change.
Rotator-cuff tear
A tear mainly limits active movement and strength while passive excursion remains available unless pain or secondary stiffness has developed.
Cervical radiculopathy
Neck-provoked pain, paraesthesia, reflex change and myotomal weakness may restrict use through pain but do not create a consistent glenohumeral capsular end point.
Calcific periarthritis
Acute deposit resorption can cause dramatic pain and guarding that mimics stiffness; radiographs show calcification and passive range improves as irritability settles.
Septic or malignant disease
Systemic illness, rapidly progressive unremitting pain, mass or destructive imaging requires urgent alternative investigation rather than assuming an unusually severe frozen phase.
07ManagementImmediate care, first-line treatment, alternatives and escalation.
01First-lineConfirm the capsular patternFirst stepFirst lineGradual pain and progressive stiffness occur without trauma, fever, deformity or neurological deficit.+
- 1Compare active and passive external rotation, elevation and internal rotation while stabilising or observing the scapula.
- 2Obtain radiographs when arthritis, previous injury, calcification or another structural diagnosis remains plausible.
- 3Explain the uncertain duration and generally improving course using individual functional goals rather than a promised recovery date.
- 4Start compatible analgesia and stage-appropriate physiotherapy with explicit advice against forceful pain-provoking manipulation at home.
02Pain-predominantCreate a tolerable movement windowNight pain and irritability prevent sleep, gentle mobility or participation in rehabilitation.+
- 1Use heat or cold according to preference, sleep positioning and gentle pendular or assisted range that settles promptly afterwards.
- 2Offer the safest short analgesic option after renal, gastrointestinal, cardiovascular, anticoagulation and pregnancy review.
- 3Consider one accurately placed intra-articular corticosteroid injection and agree how movement will progress during the response.
- 4In diabetes, plan glucose checks for several days and provide infection and post-injection flare safety advice.
03RecoveryProgress range then strengthRest pain has eased enough to permit sustained rehabilitation without prolonged flare.+
- 1Increase capsular stretching gradually in external rotation, elevation and behind-back reach without using uncontrolled force.
- 2Add cuff, scapular and functional strengthening through the newly available range.
- 3Measure passive external rotation and meaningful activities every several weeks rather than judging day-to-day variability.
- 4Address neck, opposite-shoulder and general deconditioning that accumulated during the painful phase.
04Specialist escalationDiscuss procedures for refractory disabilityEscalationMajor pain or restriction persists despite diagnosis review, supported rehabilitation and appropriate injection treatment.+
- 1Reconfirm that arthritis, cuff failure, infection and cervical disease do not better explain the residual limitation.
- 2Refer for discussion of hydrodilatation, manipulation under anaesthesia or arthroscopic capsular release within the local pathway.
- 3Review diabetes, osteoporosis, anticoagulation, anaesthetic risk and the complications specific to each procedure.
- 4Arrange immediate postoperative or post-procedure physiotherapy because newly gained range can be lost without active follow-through.
Key medicines and prescribing safety3 treatments · regimens, roles and cautions+
Paracetamol for short rescue use
Take paracetamol 500–1000 mg orally when required, leaving at least 4 hours between administrations and keeping the total at or below 4 g each 24 hours; reduce the ceiling for low weight, frailty, malnutrition or liver risk.Check all combination products to prevent overdose, reduce dose for relevant hepatic risk, and review continued use because benefit in musculoskeletal pain is often modest.
Short-course oral NSAID with protection when indicated
If suitable, use naproxen 250–500 mg orally twice daily with food for the shortest effective course and add omeprazole 20 mg orally once daily during treatment when gastroprotection is needed.Avoid or modify for ulcer disease, kidney impairment, heart failure, uncontrolled hypertension, cardiovascular risk, anticoagulants and antiplatelets; follow pregnancy restrictions from 20 weeks and avoid in the third trimester.
Intra-articular triamcinolone acetonide
Give one glenohumeral injection of triamcinolone acetonide 20–40 mg using an aseptic trained local protocol, with image guidance where commissioned, then review clinical response before any further procedure.Exclude infection and damaged overlying skin, assess bleeding risk, warn about flare, skin atrophy and rare infection, and arrange additional glucose monitoring for several days in diabetes.
08ComplicationsImportant consequences, why they occur and why they matter clinically.
Persistent contracture
Some people retain external-rotation or elevation loss for years, affecting dressing, hygiene, sleep, driving and overhead occupation despite less pain.
Compensatory pain
Scapulothoracic substitution and guarded neck movement can overload trapezius, cervical structures and the opposite shoulder while masking true glenohumeral range.
Metabolic disruption
Corticosteroid injection can transiently raise glucose, which matters in a population with a high prevalence of diabetes and may require planned monitoring.
Procedural injury
Manipulation or surgery can cause fracture, cuff injury, dislocation, nerve damage, infection or recurrent stiffness, risks that must be balanced against refractory disability.
09Monitoring and follow-upTreatment response, safety checks and longer-term review.
- Track passive external rotation, elevation, hand-behind-back reach, sleep and one valued daily activity at agreed intervals.
- During the painful phase, monitor whether exercises settle by the next day and reduce intensity if a sustained severe flare follows.
- After steroid injection, assess glucose where relevant, screen for increasing pain or fever and document whether function actually improved.
- Reconsider radiographs or alternative diagnosis if stiffness progresses unusually fast, systemic features develop or passive restriction becomes mechanically blocked.
- After hydrodilatation, manipulation or release, ensure rapid access to rehabilitation and watch for fracture, neurological change, infection or recurrent stiffness.
- Review analgesic toxicity and deprescribe when sleep and movement no longer improve meaningfully.
10Special situationsVariants, exceptions and circumstances that change the usual approach.
External rotation is the discriminator
Testing passive rotation with the arm by the side helps separate capsular contracture from a cuff that is painful during active elevation.
Phases overlap
Pain, stiffness and recovery do not switch on fixed dates; treatment should follow current irritability and function rather than a calendar label.
Scapular movement can mislead
A patient may appear to elevate farther by rotating the scapula, so assess true glenohumeral contribution and compare sides.
A normal radiograph is useful
It does not visualise capsular fibrosis, but it helps exclude osteoarthritis and other bony explanations for a stiff shoulder.
Steroid treats pain before fibrosis
Early anti-inflammatory benefit can facilitate movement; injection should not be described as mechanically dissolving a contracted capsule.
Diabetes changes counselling
The course may be longer and glucose may rise after injection, yet these issues support tailored care rather than therapeutic nihilism.
11Common pitfallsFrequent interpretation and management errors.
- 01
Diagnosing frozen shoulder from painful active elevation without demonstrating passive external-rotation restriction.
- 02
Skipping radiographs when arthritis, trauma or destructive disease could explain a genuinely stiff joint.
- 03
Ordering MRI as routine confirmation and then attributing symptoms to an incidental degenerative cuff tear.
- 04
Applying forceful stretching during a highly irritable phase and interpreting the resulting flare as disease progression.
- 05
Giving repeated injections without a rehabilitation objective, glucose plan or reassessment of benefit and diagnosis.
- 06
Promising recovery by a fixed month or assuming that every patient regains completely normal movement.