Computer navigation and fixator-assisted femoral osteotomy for correction of malunion after periprosthetic femur fracture.

Periprosthetic femoral fracture post-total knee arthroplasty can lead to malunion. This may lead to abnormal force transmission and accelerated wear of the prosthesis. Accurate femoral deformity correction depends on the combined correction of the mechanical axis alignment and the lateral distal femoral angle. Modern external fixation correction devices allow for simultaneous gradual corrections in multiple planes through one osteotomy site. Despite the accuracy of the devices, technical failures occur and are typically due to difficulty in assessing the exact intraoperative correction. Furthermore, conventional intraoperative measurements display high interobserver and intraobserver variations. Computer navigation has demonstrated great accuracy. Combining a mechanical corrective device and navigation should allow for increased precision and dynamic control intraoperatively. The current authors report on a clinical application of a novel minimally invasive fixator-assisted correction of a posttraumatic distal femoral varus deformity after total knee arthroplasty with combined navigated measurements.