Indications for unicompartmental arthroplasty of the knee
This is an area of some controversy, and some surgeons are opposed to unicompartmental arthroplasty. It is indicated in a patient with at least 90 to 110 degrees of flexion arc and arthritic involvement of only one compartment of the knee. It is contraindicated in inflammatory arthritis, <90 to 110 degrees arc of motion, absence of the anterior or posterior cruciate ligaments, flexion contracture (>15 degrees), fixed angular deformity (varus >15 degrees or valgus >20 degrees), and/or involvement of the patellofemoral compartment. It is accomplished by resurfacing the femoral and tibial joint surface in the involved compartment. Revision to total knee replacement is possible, but this is technically more difficult and has higher complication and failure rates than primary arthroplasty.