Computer Assisted Navigation Surgery Obviates the Need of Extensive Soft Tissue Release During Total Knee Arthroplasty for Varus Knees

Abstract

Introduction: We aim to (a) evaluate the kinematic patterns of varus deformities in patients with osteoarthritic knees (b) compare our result with literature published in the past and identify a valid classification scheme for the kinematic patterns of varus deformity, and (c) validate the concept of need-based soft tissue release in TKA. Methods: The computer navigations data for all those patients who underwent TKA for varus deformity was extracted and was used to assess the change in coronal plane alignment throughout the range of motion. Clinically, patient satisfaction levels were assessed by using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and functional outcomes were assessed using the Knee Society Score (KSS). Results: 120 patients satisfied the inclusion criteria set for the study. The mean age of the patients was 62.5 ± 7.09 years. The mean preoperative varus deformity was 9.5º ± 4.99o, which was correctable to a mean of 2.88º ± 2.48o in full extension. It was found that 74 (61.7%) patients had correctable varus while 46 (38.3%) had non-correctable varus. Based on the deformity pattern, the soft tissue release required was different in each group of patients. There was a statistically significant improvement both the clinical parameters (p < 0.001). Conclusion: Computer Assisted Navigation System helps to identify the dynamic nature of knee deformity before bone resections and soft tissue release. The soft tissue release for balancing the knee in varus osteoarthritic knees can be tailored sequentially according to need-base for a given pattern of deformity.