Comparison of joint line position changes after primary bilateral total knee arthroplasty performed using the navigation-assisted measured gap resection or gap balancing techniques

Abstract

This study aimed to compare the clinical and radiological results of navigation-assisted TKAs performed using the measured gap resection or the gap balancing technique in thirty patients who underwent bilateral primary TKAs. Sixty cases of navigation-assisted TKAs [30 TKAs performed using the measured gap resection technique (Group A) and 30 TKAs performed using the gap balancing technique (Group B)] were analyzed prospectively with minimum follow-up of 2 years. The joint line positions were measured using preoperative and postoperative weight-bearing anteroposterior and lateral radiographs. Clinical results were evaluated using knee scores and functional scores. No significant differences in knee scores or functional scores were observed. Polyethylene thickness and flexion/extension gaps were significantly larger in Group B (P < 0.05). The meaningful proximal shift of the joint line was shown in Group B (P < 0.05). The navigation-assisted TKA with measured gap resection technique could be a useful technique with regard to restoration of the joint line. II.