Shoulder OA

ACJ OA - history: pain at the top of the shoulder (patients often point directly to the joint), worse with cross-body movements (reaching across, seatbelt), aggravated by overhead pressing, bench press, push-ups. Many radiographic ACJ OA cases are asymptomatic.

ACJ OA - examination:

• •Localised tenderness over the ACJ
• •Positive cross-body adduction (scarf) test reproducing pain at the ACJ
• •High-arc pain above 120 degrees of abduction (distinguishes from subacromial pain at 60-120 degrees)
• •Preserved passive glenohumeral ROM
• •ACJ may be visibly prominent or swollen

GHJ OA - history: deep poorly localised shoulder pain, gradual onset of stiffness and reduced ROM, mechanical pattern (worse with activity, eases with rest), night pain in advanced disease, progressive functional difficulty. In cuff tear arthropathy: long history of shoulder weakness preceding the stiffness and pain.

GHJ OA - examination:

• •Restricted active AND passive ROM in capsular pattern: external rotation > abduction > internal rotation. Loss of passive external rotation is often the earliest and most sensitive sign
• •Crepitus on movement
• •Pain at end-range in all directions
• •Advanced disease: fixed deformity, muscle wasting
• •Cuff tear arthropathy: pseudoparalysis alongside OA features

Red flags: fever, acute swelling, erythema (septic arthritis - urgent same-day); weight loss or cancer history (proximal humerus metastasis); rapidly progressive joint destruction (AVN, crystal arthropathy, Milwaukee shoulder); bilateral pain with prolonged morning stiffness and raised inflammatory markers (inflammatory arthritis, PMR).

Differentials: frozen shoulder (capsular restriction but no crepitus or radiographic OA changes); cuff tendinopathy (painful arc with preserved passive ROM); cuff tear (weakness on resisted testing, passive ROM preserved unless secondary stiffness); calcific tendinopathy (acute severe pain, calcium on X-ray); inflammatory arthritis; PMR; AVN of the humeral head (early preserved joint space with humeral head sclerosis or collapse); Milwaukee shoulder (destructive arthropathy in elderly with large bloody effusion, basic calcium phosphate crystal arthropathy).

ACJ OA: AP shoulder may underestimate ACJ changes. The Zanca view (10-15 degree cephalic tilt) improves visualisation and shows joint space narrowing, sclerosis, and osteophytes. Radiographic ACJ OA is very common and does not always correlate with symptoms.

GHJ OA: BESS recommends true AP and axillary views. The X-ray shows joint space narrowing, subchondral sclerosis, osteophytes (the inferior humeral head osteophyte is characteristic), and subchondral cysts. The axillary view assesses posterior glenoid wear and underpins Walch typing.

Cuff tear arthropathy is suggested by superior humeral head migration, reduced acromiohumeral distance (under 7 mm), and acetabularisation of the acromion.

Ultrasound or MRI: not routinely required for OA diagnosis. Arrange via local MSK or secondary care pathway if a coexisting cuff tear is suspected, the diagnosis is uncertain, or pre-surgical planning is needed (NHS Evidence-Based Interventions framework).

Bloods: not required for primary OA. Request CRP, ESR, and a rheumatology screen if inflammatory arthritis, crystal arthropathy, or infection is suspected.

Outcome measures: Oxford Shoulder Score, SPADI.

Based on NICE NG226 (2022) OA principles adapted to the shoulder.

First-line (community):

• •Education: explain that OA does not always progress and that exercise and self-management are the cornerstones
• •Therapeutic exercise per NG226: local muscle strengthening (rotator cuff, periscapular stabilisation, ROM) plus general aerobic fitness
• •Weight management: core treatment if overweight or obese
• •Activity modification: adjust overhead tasks, ergonomic review

Pharmacological (NICE NG226):

• •Topical NSAID first
• •Oral NSAID at the lowest effective dose with gastroprotection if topical ineffective
• •Do not routinely offer paracetamol as sole analgesic for OA
• •Do not offer opioids, acupuncture, glucosamine, chondroitin, or intra-articular hyaluronic acid

Injection therapy:

• •ACJ OA: targeted corticosteroid injection within local MSK pathway provides short-term relief and has a diagnostic role - pain abolition confirms the ACJ as source
• •GHJ OA: per NG226, consider intra-articular corticosteroid when other treatments are ineffective or to support therapeutic exercise. Short-term relief only (2-10 weeks); response is NOT a reliable predictor of surgical outcome
• •Warn diabetic patients about transient hyperglycaemia

Referral (per NG226): consider joint replacement when symptoms substantially affect quality of life and non-surgical management is ineffective. Do not exclude based on age, sex, smoking, comorbidities, or obesity. For ACJ OA: at least one injection and 3-6 months of physiotherapy before surgical discussion.

Surgical options (awareness):

• •ACJ OA: arthroscopic distal clavicle excision (Mumford procedure)
• •GHJ OA with intact cuff: anatomical total shoulder replacement (superior outcomes to hemiarthroplasty for primary OA)
• •GHJ OA with cuff-deficient or cuff tear arthropathy: reverse total shoulder replacement
• •Hemiarthroplasty: less commonly used for primary OA; may suit selected fracture or AVN cases with preserved glenoid
• •Per NG226: do not offer arthroscopic lavage or debridement for OA

Exercise is the core treatment per NICE NG226. Some initial increase in pain is normal but consistent regular exercise is beneficial.

• •ROM exercises: pendular, passive, and active-assisted ROM (especially external rotation)
• •Strengthening: progressive rotator cuff and periscapular work; isometric initially if painful, progressing to isotonic
• •Aerobic exercise: swimming, walking, cycling
• •Activity modification: for ACJ OA, modify bench press, push-ups, cross-body movements

Post-arthroplasty:

• •Sling 2-6 weeks
• •Early passive ROM
• •Active ROM from approximately 6 weeks
• •Strengthening from approximately 12 weeks
• •Full recovery 3-6 months

Set realistic expectations: OA is managed, not cured. Outcome measures (Oxford Shoulder Score, SPADI) track response.

Modifiable factors: smoking slows recovery from arthroplasty (signpost NHS Stop Smoking services); weight optimisation; diabetes glycaemic control; and graded return-to-work planning.

• •NICE NG226 (2022) Osteoarthritis in over-16s - The governing UK guideline. Therapeutic exercise and weight management are core; topical NSAIDs first-line. Commonly tested do-not-offer rules: paracetamol alone, opioids, acupuncture, glucosamine, chondroitin, intra-articular hyaluronic acid, arthroscopic lavage or debridement.
• •Walch classification - Glenoid wear patterns in primary GHJ OA: Type A concentric, Type B posterior wear with subluxation, Type C retroversion. Drives surgical implant selection.
• •BESS shoulder care pathways - Recommend true AP and axillary views for GHJ OA; structured rehabilitation precedes injection or referral for joint replacement.
• •Anatomical TSR vs Reverse TSR - Intact cuff = anatomical TSR (superior outcomes vs hemiarthroplasty in primary OA); cuff-deficient or cuff tear arthropathy = reverse TSR. Hemiarthroplasty is reserved for selected fracture or AVN cases.
• •NHS Evidence-Based Interventions (EBI) - Provides the referral threshold framework for shoulder imaging and joint replacement in secondary care.

• •ACJ OA produces high-arc pain above 120 degrees with positive scarf test and localised ACJ tenderness. Subacromial impingement produces mid-arc pain at 60-120 degrees. The most commonly tested shoulder pain distinction.
• •GHJ OA restricts both active AND passive ROM in a capsular pattern (external rotation > abduction > internal rotation) WITH crepitus. Preserved passive external rotation effectively excludes GHJ OA and frozen shoulder.
• •NICE NG226 do-not-offer rules for OA: paracetamol alone, opioids, acupuncture, glucosamine, chondroitin, intra-articular hyaluronic acid, arthroscopic lavage or debridement. High-yield SBA distractors.
• •Anatomical TSR for intact cuff; Reverse TSR for cuff-deficient shoulder or cuff tear arthropathy. Hemiarthroplasty is rarely first choice for primary OA.
• •Rapidly destructive arthropathy in an elderly patient with a large bloody effusion = Milwaukee shoulder (BCP arthropathy). Young patient with humeral head sclerosis or collapse and preserved joint space = AVN - ask about corticosteroids and alcohol.