Osteoarthritis of the knee is the progressive loss of articular cartilage, with bone remodelling, synovial inflammation and, over time, deformity of the limb. It is the single most common cause of chronic knee pain in adults and the leading indication for knee replacement.
Age, genetic predisposition and female sex are non-modifiable factors. Obesity is the most important modifiable one: every kilogram of body weight multiplies through the knee several times during walking. Previous injury — a meniscal tear, an anterior cruciate ligament rupture or an intra-articular fracture — leads to post-traumatic arthritis, often decades later. Varus or valgus malalignment concentrates load on one compartment and accelerates wear. Inflammatory arthritis and previous infection are further causes.
Pain that is worse on weight-bearing, on stairs and after activity, and that in advanced disease is present at rest and at night. Morning stiffness lasting under thirty minutes. Recurrent swelling. Crepitus. Giving way from quadriceps inhibition. Progressive loss of extension and flexion, and a bow-legged or knock-kneed appearance that develops over years. Symptoms fluctuate, and a bad month does not mean the joint has suddenly deteriorated.
Weight-bearing anteroposterior, lateral and skyline radiographs are essential — a non-weight-bearing film underestimates joint space loss. Long-leg alignment views are obtained when osteotomy or partial replacement is being considered. MRI is not needed to diagnose osteoarthritis and often confuses matters by showing degenerate meniscal tears that are a consequence rather than a cause of the arthritis.
Weight reduction and quadriceps and hip abductor strengthening have the best evidence base of any intervention. Low-impact activity — cycling, swimming, cross-training — maintains cartilage nutrition and muscle. Paracetamol and short courses of non-steroidal anti-inflammatories, topical preparations, a stick in the opposite hand and appropriate footwear all help. Intra-articular corticosteroid injection relieves an inflammatory flare; hyaluronic acid and platelet-rich plasma have a role in mild to moderate disease, with more modest and shorter-lived effects.
Arthroscopic washout has no lasting benefit in established arthritis and is not indicated. In younger patients with malalignment and single-compartment disease, a high tibial or distal femoral osteotomy transfers load to the healthy side and can defer replacement for many years. Where wear is confined to one compartment with intact ligaments, a partial knee replacement preserves the rest of the joint. For advanced tricompartmental disease, total knee replacement, with robotic assistance where appropriate, reliably relieves pain and restores walking.
Surgery is driven by symptoms and function, not by the appearance of the X-ray. The right time is when pain limits sleep, walking and the activities that matter to you despite proper conservative treatment. A second opinion is worthwhile before committing to any operation.
to guide you about your condition, to choose the best possible treatment.
