To study the effect of using gap balance technique versus measuring osteotomy technique in total knee arthroplasty on postoperative knee joint function, lower extremity alignment changes, and intraoperative osteotomy parameters in patients with knee osteoarthritis.

From October 2019 to May 2021, 81 patients with knee osteoarthritis who underwent unilateral total knee arthroplasty at Xing'anmeng People's Hospital were included, of which 30 underwent femoral osteotomy using the gap balance technique (using a novel femoral measurement locator; experimental group), and 51 underwent femoral osteotomy using the combined technique of measuring osteotomy and gap balance (control group). The operation time, intraoperative parameters (the amount of osteotomy of the lateral tibial plateau, the amount of osteotomy of the distal femur, the amount of osteotomy of the posterior medial condyle of the femur, the amount of osteotomy of the posterior lateral condyle of the femur, and the thickness of the spacer) were compared between the two groups. Posterior knee pain visual analogue scale (VAS) score, knee range of motion, knee society score (KSS), Western Ontario MacMaste (WOMAC) score, and related imaging parameters were also compared.

The osteotomy of the posterior medial condyle of the femur (9.0±0.98 vs 9.7±01.0, t=-3.212, P=0.002) was less and the thickness of the spacer (8.2±0.6 vs 9.4±1.1, t=-4.939, P=0.001) was thinner in the experimental group than in the control group. The KSS (74.8±13.7 vs 66.9±14.5) and WOMAC score (32.9±7.8 vs 38.9±8.1) at the 1-month follow-up were significantly better in the experimental group (P<0.05), suggesting a faster recovery of knee joint function. There was no significant difference in KSS or WOMAC score at 6 months, 1 year, and last follow up after operation between the two groups (P>0.05). The plateau angle was significantly corrected in both groups after operation (P<0.05), but there was no significant difference in the femoral-tibial angle or tibial plateau angle between the two groups after surgery (P>0.05).

The use of the new femoral measuring locator for gap balance osteotomy in total knee arthroplasty can achieve ideal flexion gap balance and reduce the amount of osteotomy on the posterior medial condyle of the femur, and the short-term postoperative knee joint function recovery is better.