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Orthopaedics · UK

Partial knee replacement - replace the worn third, keep the rest.

When arthritis is confined to one compartment of the knee - as it is in roughly one patient in four - resurfacing just that compartment means a smaller operation, a faster recovery, and a knee that feels more like your own.

See indicative pricing
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Indicative pricing

What a private partial knee replacement costs in the UK.

Indicative ranges across UK orthopaedic units.

In short

£12,000–£16,500, walking the same day.

Procedure Indicative range
Knee surgeon consultation £250–£400
Weight-bearing and stress X-rays £150–£300
MRI knee (borderline cases) £450–£800
Partial (unicompartmental) knee replacement £12,000–£16,500
Robotic-assisted partial knee replacement £14,000–£18,500
Patellofemoral replacement £12,500–£17,000
Total knee replacement (for comparison) £14,000–£19,000

Prices vary by hospital, surgeon and implant, and by whether robotic assistance is used.

The problem

The right operation, the right surgeon, and selection you can trust.

Partial knees fail for reasons decided before theatre - offered to knees that need totals, done by surgeons who do three a year, or never offered at all. We fix all three.

  • A quarter of knees, not all of them

    Partials excel precisely when selection is strict. Stress X-rays and ligament checks decide - enthusiasm does not.

  • Volume halves revision risk

    Registry data is unambiguous: surgeons doing partials weekly revise far fewer. That statistic is our selection policy.

  • The option too rarely offered

    Many suitable patients are simply never told a partial exists. A second opinion before a total knee costs nothing and can change the next twenty years.

When it helps

When a partial knee is the right operation.

The patterns we see most, plus the one red flag after surgery that needs urgent review rather than reassurance.

  • Pain on the inner side of the knee

    Medial compartment arthritis is by far the commonest pattern - pain localised to the inside of the joint, worse on standing and walking.

  • Arthritis confined to one compartment

    X-rays showing bone-on-bone in one compartment with the rest preserved - the anatomical case for replacing a third, not the whole.

  • A stable knee with good movement

    Intact cruciate ligaments and a knee that still bends well - the functional requirements that make a partial work for decades.

  • Pain behind the kneecap

    Isolated patellofemoral arthritis - pain on stairs and rising from chairs - suits a patellofemoral replacement in selected patients.

  • Injections and physio exhausted

    When weight management, physiotherapy, braces and injections no longer hold the line, resurfacing the worn compartment is the logical next step.

  • The younger, active patient

    Partials preserve bone and ligaments, keep more natural movement, and make any future revision more straightforward - attractive trade-offs at 55.

  • Osteonecrosis of one condyle

    Spontaneous osteonecrosis (SONK) destroying a single femoral condyle is a classic partial-knee indication when caught before collapse spreads.

  • Red flag: hot, swollen implant with fever

    A red, hot, increasingly painful replaced knee with fever is infection until proven otherwise - same-day contact with the team or A&E, never antibiotics from afar.

Procedure options

One knee, three compartments - and several honest options.

What each option involves - and how a partial compares with the total knee replacement you may also have been offered.

  • Medial unicompartmental replacement

    The workhorse - resurfacing the inner compartment, around 90% of all partials. Excellent, durable results in well-selected knees.

  • Lateral unicompartmental replacement

    The rarer outer-side equivalent, technically distinct and best concentrated in surgeons who do it regularly.

  • Patellofemoral replacement

    Resurfacing the kneecap groove alone for isolated patellofemoral arthritis - a small, targeted implant in the right pattern of wear.

  • Mobile- and fixed-bearing designs

    Two established implant philosophies with comparable outcomes in experienced hands - your surgeon will explain their choice and their numbers.

  • Robotic-assisted partial knee

    Robotic platforms plan and execute bone cuts to sub-millimetre targets. Evidence shows more accurate positioning; registry survivorship differences are still maturing.

  • Total knee replacement

    The right operation when arthritis involves multiple compartments or the ACL is gone - more predictable for widespread disease, at the cost of a bigger recovery.

  • High tibial osteotomy

    Realigning the leg to unload the worn compartment - the joint-preserving alternative for younger, active patients with early single-sided wear.

  • Staying non-operative

    Weight loss, structured physiotherapy, braces and judicious injections - still worth optimising, and occasionally enough to shelve surgery for years.

Safety and recovery

What to expect afterwards - honestly.

Partial knee replacement recovers faster and feels more natural than a total - and carries a somewhat higher chance of needing revision one day. Both halves of that sentence belong in honest consent.

  • A smaller operation, genuinely

    Less bone removed, ligaments preserved, less blood loss and a shorter stay than total replacement - most patients walk within hours.

  • Pain relief and function

    Around 9 in 10 patients get substantial, lasting pain relief; partial knees consistently score higher than totals for feeling “natural”, kneeling and stairs.

  • Infection

    Deep infection affects well under 1% - lower than total replacement. Skin, dental and diabetes checks beforehand exist to keep it that way.

  • Clots

    DVT and PE are recognised risks of any knee replacement; mechanical and drug prophylaxis are routine, and early walking is itself protective.

  • Revision, honestly quoted

    Registry data shows partials are revised more often than totals - roughly 10–15% by 15 years overall, but markedly lower in high-volume hands.

  • Arthritis can progress elsewhere

    The untouched compartments can wear in later years - one reason careful selection matters, and the commonest reason a partial is eventually converted to a total.

  • Conversion is straightforward-ish

    If revision is ever needed, a partial usually converts to a standard total knee - an easier operation than revising a failed total. Bone preserved now is options preserved later.

  • The timeline, realistically

    Driving at 3–4 weeks, desk work at 2–3, most sports (golf, cycling, doubles tennis) by 3–4 months. Swelling and warmth grumble on for months - normal, and worth knowing.

  • Red flags after surgery

    Calf pain or breathlessness, a hot swollen joint with fever, or a wound leaking beyond the first days need same-day contact - every patient leaves with the direct number.

Reading your operation note

Your operation note in four parts. Read the last one first.

Whether your partial was conventional or robotic-assisted, the note the surgeon sends you keeps to the same shape.

A UK knee surgeon reviewing a patient’s operation notes and X-rays

A quiet reminder

Implant names, sizes and angles read like a parts catalogue - ask your care team to explain them if anything is unclear.

Ask your care team to explain anything that is unclear.

  1. 01 Header

    Diagnosis, compartment and approach

    Which compartment was replaced and why, the anaesthetic used, and whether the procedure was robotic-assisted.

  2. 02 Technique

    Implant and alignment detail

    The implant brand, sizes and bearing type, plus the alignment achieved - the data your national joint registry entry is built from.

  3. 03 Findings

    The rest of your knee

    The state of the other compartments and ligaments seen at surgery - the honest forecast for how long this knee should serve.

  4. 04 Impression

    Rehab plan and review dates

    Read this first: weight-bearing status, physio milestones, wound care, clot prophylaxis doses, and when X-ray review is booked.

Recognised by major UK insurers

BupaAXA HealthVitalityAvivaWPACignaHealixBupaAXA HealthVitalityAvivaWPACignaHealixBupaAXA HealthVitalityAvivaWPACignaHealix

Partial knee replacement is routinely covered by UK private medical insurance for symptomatic arthritis that has failed conservative care, including robotic-assisted surgery in most policies.

Frequently asked

Everything we get asked about partial knees.

Quick answers on suitability, partial vs total, robotics, longevity, recovery and cost.

  • What is the difference between a partial and a total knee replacement?

    A total replacement resurfaces the whole joint and removes the anterior cruciate ligament; a partial resurfaces only the worn compartment - usually the inner third - and keeps both cruciates and all healthy cartilage. The result is a smaller operation, roughly half the recovery time, and a knee more patients describe as feeling natural. The price is a somewhat higher lifetime chance of revision.

  • Am I suitable for a partial knee replacement?

    Roughly one in four patients needing knee replacement is. The requirements: arthritis genuinely confined to one compartment on weight-bearing and stress X-rays, intact cruciate ligaments, a correctable deformity and reasonable movement. Age and weight matter less than they once did.

  • How long does a partial knee last?

    National registry data shows around 85–90% of partial knees still in place at 15 years overall - and meaningfully better than that from high-volume specialist units, where survivorship approaches total-knee figures. If revision is ever needed, a partial usually converts to a standard total knee rather than complex revision surgery.

  • Is robotic surgery worth it?

    Robotic platforms demonstrably improve the accuracy of implant positioning, and early registry signals for robotic partials are encouraging, though long-term superiority is not yet proven. Where UK surgeons use robotics, it typically adds £1,500–£2,500. We present it as it is: a precision tool in good hands, not a substitute for surgeon volume.

  • How quick is the recovery, honestly?

    Most patients walk the day of surgery, go home within a day or two, drive at three to four weeks and walk unaided by four to six. Desk work resumes at two to three weeks. The knee keeps improving - swelling settling, trust returning - for six to twelve months. It is a genuinely faster course than a total, but it is still a joint replacement, not a scope.

  • How much does a private partial knee replacement cost?

    Typically £12,000–£16,500 all-in - implant, hospital, anaesthetist, initial physio - rising to £14,000–£18,500 with robotic assistance. A total knee runs £14,000–£19,000 for comparison. Insured patients are routinely covered.

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