Description
【Objective】 Anterior tibial subluxation (ATS) in knee extension is seen in anterior cruciate ligament (ACL) injured knees. It has been reported that preoperative ATS adversely affects postoperative anterior and rotation stability and risks early graft failure. The purpose of this study was to investigate the associated factors with preoperative ATS in ACL injured knees.
【Methods】 A total of 191 patients who underwent primary ACL reconstruction at our hospital were included (98 females, 93 males) between July 2017 and December 2022. Preoperatively, all patients were taken lateral radiographs in full extension of both knees to evaluate ATS. ATS was measured the distance between a perpendicular line to femoral condyles and tibial condyles with respect to the medial tibial plateau to one decimal place. These 191 patients were divided into 2 groups based on the positive ATS. Positive ATS was defined as a preoperative SSD in ATS more than +SD from average preoperative SSD in ATS. Evaluation items were age, sex, height, weight, time from injury to surgery, mechanism of injury, PTS, knee extension deficit, ATT, and meniscal tear in arthroscopy.
【Result】 In total, the 191 patients were divided into 2 groups based on the positive ATS: positive ATS group (32 patients); negative ATS group (159 patients). The overall average of preoperative SSD in ATS was 1.7 ± 1.9 mm. Therefore, ATS of more than 3.6 mm was regarded as positive ATS. In the positive ATS group, the ratio of more than 6 months from injury to surgery and the ratio of non-contact injury was significantly higher. The contralateral hyper extension angle and SSD in ATT were significantly greater in the positive ATS group. There was no significant difference between 2 groups in meniscal tears. Logistic regression analysis indicated that the positive ATS predictors were SSD in ATT (odds ratio [OR], 1.27; 95% confidence interval [CI95], 1.13-1.45; p<0.001), more than 6 months from injury to surgery (odds ratio [OR], 2.59; 95% confidence interval [CI95], 1.07-6.27; p=0.035), the contralateral hyper extension angle (odds ratio [OR], 1.10; 95% confidence interval [CI95], 1.00-1.21; p=0.045).
【Conclusion】 Anterior knee laxity and Chronicity of ACL-deficiency, Knee hyperextension affect preoperative ATS in ACL injured knees.
