The flexion gap preparation does not disturb the modified gap technique in posterior stabilized total knee arthroplasty

Midflexion Laxity After Implantation Was Influenced by the Joint Gap Balance Before Implantation in TKA

“…The pattern of joint gap kinematics after implantation in group 1 was very similar to that in PS TKA using measured resection technique [9]. Even if the sizes of extension and flexion joint gaps were prepared equally before implantation using gap balancing technique [8], midflexion laxity was still observed after implantation (group 2). To minimize the midflexion laxity after implantation, the flexion joint gap should be made smaller than the extension joint gap before implantation (group 3).…”

“…These mechanisms reflect the design feature of the component and allow for the reproduction of joint kinematics after implantation of the components. Interobserver and intraobserver variabilities of this device with 20 subjects have been previously reported [8]. The mean absolute value of the difference between 2 repeated measurements by 1 observer was 0.2 mm (95% confidence interval, − 0.1 to 0.4 mm) and 0.1°(95% confidence interval, − 0.2°to 0.4°).…”

“…All procedures were performed using the same surgical technique, which we previously published as the modified gap balancing technique [8]. The knees were exposed using a medial parapatellar approach, and The Journal of Arthroplasty 30 (2015) 762-765…”

“…Joint gap before implantation was measured using our previously validated technique [6,8]. After trial components were removed, the joint gap was measured at 0°of extension and 90°of flexion at 120 N of distraction force.…”

“…However, the relationship between the joint gap balance before implantation and the midflexion joint gap laxity after implantation has not been investigated yet. A previous report showed that the size of the extension and flexion joint gaps before implantation can be controlled by the operative technique such as modified gap balancing technique [8]. If the joint gap balance before implantation influences a degree of midflexion laxity after implantation, midflexion laxity after implantation can be modified and decreased by the operative technique.…”