What is knee osteoarthritis?
Knee osteoarthritis occurs when the cartilage cushioning the knee joint gradually wears down, leading to pain, swelling, stiffness and sometimes a change in the shape or alignment of the leg. It is one of the most common joint problems in the UK, typically affecting people over 50, and is more likely after previous knee injury or surgery, in people who are overweight, and in those with physically demanding jobs.
A GP or physiotherapist can often diagnose knee osteoarthritis from your symptoms and an examination alone. An X-ray may be used to confirm the diagnosis or assess severity, particularly if surgery is being considered. MRI is rarely needed unless another problem, such as a meniscus tear, is suspected.
Common symptoms
- Pain in or around the knee, worse with activity
- Stiffness after rest that eases with movement
- Swelling around the joint
- Grinding, creaking or crunching sensations
- The knee giving way or feeling unstable
- Difficulty with stairs, kneeling or squatting
- Gradual bowing or change in leg alignment
How long will you wait?
Routine NHS referral through to knee replacement frequently takes six to twelve months or longer at many trusts, with trauma and orthopaedics among the specialties under most pressure.
Privately, you can typically see a knee specialist within 3–7 days, with joint replacement surgery usually scheduled within 2–6 weeks.
NHS England median referral-to-treatment wait: 12.4 weeks, with 2.5 million people waiting over 18 weeks (May 2026). Individual waits vary by trust and urgency.
Treatment options
- Exercise and physiotherapy. Strengthening the thigh muscles is one of the most effective treatments for knee osteoarthritis at any stage.
- Weight loss. Each kilogram lost meaningfully reduces the load passing through the knee with every step.
- Steroid injections. A corticosteroid injection can settle a painful flare for weeks to months, useful while building up other treatment.
- Partial knee replacement. When wear is confined to one part of the knee, replacing only that compartment preserves more natural movement.
- Total knee replacement. The worn joint surfaces are replaced with metal and plastic components, giving reliable pain relief in advanced disease.
What does private treatment cost?
As a guide, self-pay total knee replacement in the UK typically costs around £13,000–£16,500, with partial knee replacement often somewhat less.
Does health insurance cover knee osteoarthritis?
Insurers routinely cover knee osteoarthritis treatment, from specialist consultations and injections through to knee replacement, when the condition arises after the policy begins. Knees that were already painful or diagnosed before you joined will normally be excluded as pre-existing, though some policies review exclusions after a symptom-free period. As a long-term condition, cover applies to acute episodes such as surgery rather than open-ended management.
Frequently asked questions
Will I definitely need a knee replacement?
No. Many people with knee osteoarthritis manage well for years with exercise, weight management and occasional injections, and only a minority ever need surgery. Replacement is reserved for knees where pain significantly limits daily life despite good non-surgical care, and the decision is always made jointly with your surgeon.
What is the difference between partial and total knee replacement?
A partial replacement resurfaces only the worn compartment of the knee, usually the inner side, preserving the rest of the joint and its ligaments. Recovery tends to be quicker and the knee often feels more natural. A total replacement resurfaces the whole joint and is used when wear is more widespread.
How long is recovery after knee replacement?
Most people are walking with support on the day of surgery or the day after, and many go home within one to three days. You can usually drive again at around six weeks. Improvement continues for up to a year, and committed physiotherapy in the first three months makes a real difference to the final result.
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