Knee Osteoarthritis

See Hip & Generalised Osteoarthritis for hip-specific management and multi-joint disease.

• Demographics: middle age and later; women, obesity, previous trauma, underlying deformity.
• History: progressive pain and stiffness, aggravated by activity and eased by rest. Descending stairs more painful than ascending points to the patellofemoral joint.
• Examination: flexion restricted, extension typically preserved; crepitus; ± varus/valgus deformity.
• Investigations: weight-bearing X-ray (clinical diagnosis — imaging severity correlates poorly with symptoms).

Management (RACGP OA guideline, 2nd edition)

Exercise and weight management are the two strong recommendations for an intervention. Everything else is conditional at best.

• Exercise. Offer land-based exercise for all people with knee OA to improve pain and function, regardless of their age, structural disease severity, functional status or pain levels. Walking, muscle-strengthening exercise and specifically Tai Chi are strongly recommended. Prescribe an individualised program and refer to an exercise professional where supervision would help. Aquatic exercise and stationary cycling are conditional options.
• Weight management. Strongly recommended for anyone overweight (BMI ≥25) or obese (BMI ≥30), with a minimum weight-loss target of 5–7.5% of body weight, and better results with more. Combine it with exercise.
• Analgesia. Oral NSAIDs at low doses for short periods, with monitoring for adverse effects. There is no recommendation either for or against paracetamol or topical NSAIDs — a short trial of either is reasonable, with monitoring, then stop if it isn’t working.
• Intra-articular corticosteroid. Short-term symptom relief; take care with repeated injections because of potential harm.
• Duloxetine. Consider when other pain relief is inadequate.
• Adjuncts (conditional): CBT, heat packs, a cane or walker, a short course of manual therapy or massage, home TENS.

Not recommended: glucosamine/chondroitin, opioids (avoid), arthroscopic lavage/debridement for OA. The guideline is a strong recommendation against oral and transdermal opioids, and against arthroscopic surgery for knee OA unless the knee is locked. Glucosamine and chondroitin, vitamin D and acupuncture should not be offered. Capsaicin, bisphosphonates, colchicine, methotrexate, viscosupplementation and PRP all carry a conditional recommendation against or no recommendation at all.

Bracing helps some patients but the evidence is weak — valgus braces and lateral wedge insoles for medial knee OA carry a conditional recommendation against.

Joint replacement for progressive pain and loss of function refractory to conservative care — optimise first (weight, comorbidities, smoking, anaemia, glycaemia; “prehabilitation” improves arthroplasty outcomes).