Private knee replacement in London, by a consultant knee surgeon.

Roughly one in three arthritic knees is suitable for a unicompartmental replacement — usually medial (about 90%), sometimes lateral. It needs isolated compartment wear, an intact ACL, a correctable deformity and minimal patellofemoral OA. When it fits, UKA gives faster recovery, more natural kinematics, and can be revised to a TKR later. We say honestly which category your knee falls into before you commit.

National Joint Registry data show around 95% of TKRs are still in place at ten years and roughly 90% at twenty years. Unicompartmental replacements have a slightly higher revision rate at ten years but revise more easily to a TKR if needed. Longevity depends on implant, alignment, weight and activity — not just brand.

Roughly £11,000–£18,000 for a standard total knee replacement, £9,000–£14,000 for a unicompartmental (Oxford / Sigma HP), £13,000–£20,000 with robotic assistance (MAKO / ROSA / Cori), and £16,000–£22,000 with a premium implant such as a medial pivot design. We confirm a firm figure within one working day.

Robotic systems — MAKO, ROSA, Cori — improve the precision of bone cuts and component positioning. Evidence for better long-term outcomes is emerging rather than settled. It is a reasonable choice, especially for unicompartmental replacements and complex deformities, but a well-planned manual TKR by an experienced consultant is not inferior in most patients.

Cemented remains the UK workhorse and has the largest evidence base. Uncemented press-fit implants are increasingly used in younger, higher-demand patients where long-term osseointegration is the goal. Neither is universally better; the surgeon matches the fixation to your age, bone quality and expected demand.

Home in one to three nights on an ERAS pathway. Off two crutches by two to three weeks, off a stick by four to six weeks, driving by four to six weeks if you can perform an emergency stop. Back to a desk job in two to four weeks, a manual job in eight to twelve. Full recovery — the last of the swelling and stiffness — takes six to twelve months.

The first two weeks are the hard part. A regional block (adductor canal and genicular nerve block) plus tranexamic acid on an ERAS pathway make the first day much more comfortable than TKR used to be. Pain then improves week by week; night pain often disappears within four to six weeks.

Symptomatic DVT or PE (1–2%), deep periprosthetic joint infection (1–2% and serious, usually needing a two-stage revision), periprosthetic fracture, ongoing stiffness or pain (the “unhappy TKR”, around 5–15%), and eventual aseptic loosening at 15–25 years. Rare complications include patellar tendon rupture, MI, pneumonia, AKI and delirium in older patients.

Kneeling is often uncomfortable after a TKR and many patients avoid it — a partial knee is usually more forgiving. Running is generally discouraged after TKR, encouraged low-impact after UKA. Skiing, cycling, doubles tennis, golf and hiking are all realistic goals once rehab is complete.

A hot, swollen, painful knee with fever after a previous replacement is a suspected periprosthetic joint infection and needs same-day A&E. So do calf pain and swelling suggestive of DVT, breathlessness or chest pain suggestive of PE, or a sudden inability to weight-bear after a fall.