RADIOLOGICAL OUTCOMES OF A HAND HELD SURGICAL NAVIGATION SYSTEM IN TOTAL KNEE ARTHROPLASTY

Introduction Failures in total knee arthroplasty (TKA) have been associated with overall lower limb malalignment and component malposition. Although traditional computer navigation systems improve component placement, they require fixation of the femoral and tibial reference arrays for software recognition using anchoring pins. This increases the risk of bony fracture, pin sites infection and osteomyelitis. Aim This study aims to evaluate the accuracy of a new hand held navigation system (BrainLAB® Dash® Navigation system) that will avoid these complications. Materials and Methods Power analysis was done prior to the conduct of this study. Two hundred patients diagnosed with tricompartmental osteoarthritis and underwent total knee arthroplasty by a senior surgeon were included in this study. 100 patients underwent TKA using the hand held navigation system while the other 100 patients underwent TKA using conventional technique. The primary outcomes of this study were the overall alignment of the lower limb and the position of the components. This was determined radiologically using the: 1) Hip-Knee-Ankle angle (HKA) for lower limb alignment; 2) Coronal Femoral-Component angle (CFA) and 3) Coronal Tibia-Component angle (CTA) for component position. Normal alignment was taken as 180 ± 3 degrees for the HKA and 90 ± 3 degrees for both the CFA and CTA. Results There was no difference in the mean HKA, CFA and CTA between the hand held navigation group and the conventional group. For the CFA, the proportion of outliers was 7% and 17% in the hand held navigation and conventional group respectively ( p =0.030). For the HKA and CTA, there was no difference in the proportion of outliers between the two groups. The duration of surgery was 73 ± 9 minutes and 87 ± 15 minutes in the hand held navigation and conventional group respectively ( p 0.001) Conclusion Dash® is an effective intraoperative tool to reduce the duration of surgery while concurrently reducing the proportion of outliers. The authors recommend its routine use in TKA.