Navigation-assisted minimal invasive total knee arthroplasty in patients with extra-articular femoral deformity.

In the presence of extra-articular femoral deformity, total knee arthroplasty (TKA) is difficult to perform because of altered anatomical axis and distorted landmarks. Although minimal invasive surgery (MIS) has known advantage of earlier rehabilitation, MIS with this deformity may have higher incidence of component malposition due to inadequate exposure. Navigation has been shown to increase the accuracy of alignment and may compensate possible complication of MIS. We report 4 cases with extra-articular femoral deformity that underwent MIS-TKA using an image-free navigation system in which preoperatively planned mechanical alignment was surgically achieved with proper positioning of the implants as well as soft tissue balance. Navigation-assisted MIS-TKA may become a valuable mean especially for a patient with a deformed femur in which conventional instruments are difficult to use correctly. Copyright 2010 Elsevier Inc. All rights reserved.