Partial (Unicompartmental) Knee Replacement

What is a partial knee replacement?

A partial knee replacement — also known as unicompartmental knee arthroplasty (UKA) — replaces only the damaged compartment of the knee rather than the entire joint surface. The knee has three compartments: medial (inner), lateral (outer) and patellofemoral (kneecap). When arthritis is confined primarily to one compartment, partial replacement can restore function while preserving healthy bone, cartilage and the cruciate ligaments in unaffected areas.

How does it differ from total knee replacement?

• Only the affected compartment is resurfaced — typically the medial compartment
• Cruciate ligaments are retained, often giving a more natural feel
• Less bone removed and a smaller incision
• Less blood loss and faster recovery in most cases
• Conversion to a total knee replacement remains possible later if needed

Robotic partial knee replacement — Mako

Partial knee replacement is an area where robotic assistance offers particular benefits. Mako-assisted UKA uses the same CT planning and haptic guidance to allow even more precise bone cuts and implant positioning in the narrow confines of a single compartment, with accurate simulation of the knee's natural movement.

Who is this for?

• Arthritis confined to one compartment of the knee
• Correctable deformity (not severe fixed varus or valgus)
• Patients who want a less invasive option with a faster recovery

My approach

• Zimmer Biomet partial knee replacement system
• Mako robotic assistance available
• Careful patient selection with thorough pre-operative imaging to confirm compartmental disease
• Available at: Meriden Nuffield Health Hospital and University Hospitals Coventry & Warwickshire

Risks

• Deep vein thrombosis (DVT) and pulmonary embolism (PE)
• Fracture
• Infection
• Stiffness
• Neurovascular injury
• Further surgery
• Failure of the implant
• Bleeding
• Disease progression in unreplaced compartments may require conversion to total knee replacement

Recovery

Recovery is generally faster than from total knee replacement. Most patients are discharged within 1–2 days and walking without crutches within 4–6 weeks.