DOES RIGID BODY FIXATION IN COMPUTER ASSISTED TOTAL KNEE ARTHROPLASTY LEAD TO POSTOPERATIVE MUSCLE DYSFUNCTION

Abstract

This prospective study is designed to assess intra-operative trauma to soft tissue envelope around the knee joint especially quadriceps due to rigid body fixation on the femur and its influence on rehabilitation outcome obtained using a kinematic navigation system for TKR. We also evaluated the impact of the extra time needed to adopt this system on immediate post-operative rehabilitation.

One hundred and sixteen operations were performed with the aid of the kinematic navigation system. Results, including operation time, radiographic alignment of the prosthesis and complications, were compared with non-navigated group. Outcome measures included preoperative knee function, intra-operative factors, blood loss and postoperative rehabilitation.

The operation time (from skin to skin) in the navigation group was average 32 minutes longer compared historical controls. No major complications such as delayed wound healing, infection or pulmonary embolism occurred during this study. Mean blood loss in both the group showed no difference

A higher incidence and duration of early postoperative quadriceps dysfunction was not associated with computer-assisted TKA through the lateral Para patellar approach. No patient who received surgery had a lag of more than 20 degrees, at 48 hours postoperatively, regardless of the duration of intra-operative time used.

Although the total surgical time was longer, it does not translated into increased postoperative morbidity. Use of a kinematic navigation system has a short learning curve, and requires an additional operation time of less than 32 minutes. We found no impact of patients’ perioperative times on short-term outcomes obtained during our learning curve and next two years. The mechanical axis of the leg was within 3 degrees of neutral alignment along with accurate component alignment. The Computer-assisted TKA through a lateral parapatellar approach was not associated with delayed recovery of the patients during early postoperative rehabilitation.