A private partial (unicompartmental) knee replacement typically costs £10,000–£14,000 in the UK as a fixed-price package, against £12,000–£16,000 for a total knee replacement — with London hospitals towards or above the top of those ranges. The gap is smaller than most people expect, often only £1,500–£2,500, because theatre, implant, anaesthetist and hospital-stay costs don’t halve just because the operation is smaller. Budget too for the initial consultation (£150–£250) and pre-operative imaging, which often sit outside the package, and always get a written itemised quote.

A partial or unicompartmental knee replacement resurfaces only the damaged compartment of the knee — most commonly the inner (medial) side — with a small prosthesis, leaving the healthy bone, cartilage and ligaments untouched. Because both cruciate ligaments are preserved, the knee tends to feel more natural than after a total replacement. It’s a smaller operation through a smaller incision, usually with less blood loss, less post-operative pain and a shorter hospital stay — in some centres it’s done as a day case.

Only around 15–20% of people needing a knee replacement are suitable, because the arthritis must be genuinely confined to one compartment with intact ligaments and reasonable alignment. Surgeons assess this with examination and imaging — X-rays and often MRI. If damage extends across compartments, a partial replacement would leave arthritic surfaces behind and a total replacement is the appropriate operation. Suitability is a surgical judgement, not a preference: the honest advice is to choose the operation your assessment supports rather than choosing partial for the smaller scar or price.

Faster than a total replacement: most people are walking with support on the day of surgery, home within one to two days (or the same day in day-case units), walking unaided at around two to four weeks, and substantially recovered at four to eight weeks, with improvement continuing for months. Physiotherapy drives the outcome — the exercises are not optional extras. As with any knee surgery, full comfort kneeling and high-impact activity take longer, and your surgeon’s plan overrides any general timeline.

Typically around four to six weeks, and often sooner after a left-knee replacement in an automatic car. The test that matters is being able to perform an emergency stop safely and control the car without hesitation — and your insurer may require confirmation you’ve been cleared to drive, so it’s worth telling them. Your surgeon or physiotherapist confirms when you’re ready; driving before you can brake properly risks both safety and your insurance cover.

The honest one: revision rates are higher than for total knee replacement — National Joint Registry analyses consistently show partial replacements are more likely to need re-operation, partly because arthritis can progress in the remaining compartments and partly for loosening. The counterweight is that a partial-to-total revision is generally a more straightforward operation than revising a total replacement, and for well-selected patients under experienced surgeons the results are excellent, with a more natural-feeling knee. Surgeon experience and correct patient selection matter more to the outcome than the implant choice.

Yes — if the arthritis developed after the policy started, partial knee replacement is treated like any eligible acute surgical condition: covered subject to pre-authorisation and your plan’s terms. The universal caveat applies: knee arthritis that already existed or was symptomatic before you took the policy out is a pre-existing condition and will typically be excluded, so insurance bought after the knee already hurts won’t fund this operation. Existing policyholders should get pre-authorisation before booking anything.

Modern knee implants are durable — National Joint Registry data shows around 96% of knee replacements last at least 10 years and around 90% reach 20 years, with partial replacements somewhat more likely to need earlier revision than totals. For many patients in their 60s or 70s a well-functioning partial replacement lasts as long as they need it; younger, more active patients are more likely to face a revision eventually, which is a genuine part of the decision conversation with your surgeon.