Changes of mediolateral soft tissue gaps in total knee arthroplasty after suturing medial extensor in navigation

Purpose:Aim is to investigate the changes of mediolateral soft tissue gaps in total knee arthroplasty (TKA) after suturing medial extensor.Methods and materials:We compared the differences of medial and lateral gap values that were shown by the computer navigation at 0°, 45°, 90°, and 120° knee flexion during patella in situ and during patella repaired by a towel clip on two constant sites. Fifty consecutive knees (43 patients) scheduled for TKA due to varus knee osteoarthritis, from February 2017 to May 2017, were enrolled in this prospective study.Results:The medial gaps with patella repaired were significantly lower (p < 0.05) than the medial gaps with patella in situ at 45°, 90°, and 120° knee flexion. Differences in the medial gap were largest at 90, with the difference of 0.87 mm. Twenty-four of 50 cases (48%) showed medial gap differences of 1 mm or over, and 13 of 50 cases (26%) showed medial gap differences of 2 mm or over. The variation in the medial gap at 90° following patellar repair showed s...