Conversion of lateral unicompartmental arthroplasty to anterior cruciate retaining tricompartmental knee arthroplasty.

This case report presents the conversion of a lateral unicompartmental arthroplasty (UKA) to an anterior cruciate retaining tricompartmental knee arthroplasty. The patient presented with disease progression to the medial and patellofemoral compartments of the knee, in addition to significant varus deformity. During revision surgery, the previously implanted UKA device was found to be well fixed and in good condition. The conventional treatment option would be conversion to total knee arthroplasty (TKA). However, in this case conversion to a tricompartmental, ligament sparing arthroplasty via implantation of a bicompartmental knee arthroplasty (BKA) device was found to be feasible. In UKA revision cases where the device is functional, the current surgical approach may be an appropriate alternative to conventional TKA.