Navigation as an Enabler of Arthroplasty in Severely Deformed Knees

Introduction: Successful results after knee replacement are based on accurate bone cuts. In most cases intramedullary cutting guides are used for correct distal femoral cut and are optional for the tibial cuts. The use of intramedullary guides is problematic in cases with femoral deformity and or other medullary lesions (tumor, infection etc.). For this cases computer assisted technology is enabler.

Materials and Methods: We retrospectively reviewed our computerized arthroplasty database using Orthosoft system. Between 2009 and 2016 we performed about 1400 primary knee replacements; in 134 (9.6%) we used computerized navigation assistance. 12 patients in the navigation group (8.95) had severe distal femoral deformities or other pathology precluding the use of the conventional intramedullary cutting guides ("enabler cases`). In all cases the navigation enables accurate cuts with no outliers (deviation from preplanning of less than 3ͦ . The procedure was longer than the conventional (average 10 min.), we did not observed any intraoperative or early complications in these patients. The long term outcome was simmilar to our conventional database outcome.

Conclusion: Computerized navigation was found to be improving tool in reducing outliers in knee replacement surgeries. When facing cases with severe deformity or other contraindication for intramedullary guidance It both enables the performance of the procedure and helps create a well aligned knee replacement. The accuracy that was achieved in this selective group indicates the quality and the potential of computer assisted technology.