Planning for minimally invasive unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) is considered the treatment of choice in patients with single compartment arthritis of the knee at early stages or with osteonecrosis limited to one compartment. However, results in the literature are still controversial and it is a technically difficult procedure. The main goal of UKA is to restore the articular space of the afflicted compartment, without influencing the limb alignment. Selection of patients and pre-operative planning are crucial. The necessity to improve functional results and to reduce immobilization of the patients has led to the development of minimally invasive surgery. Applied to UKA, this approach reduces blood loss and surgical time, causes fewer symptomatic postoperative complications, and permits earlier recovery compared to the traditional incision. The shorter incision makes careful pre-operative planning essential. We briefly review the indications for UKA, the pre-operative clinical and radiological assessment, and the surgical procedure.