[Risk factors for contralateral anterior cruciate ligament injury after primary anterior cruciate ligament reconstruction].

To investigate the risk factors of contralateral anterior cruciate ligament (ACL) injury after primary ACL reconstruction.A retrospective review was conducted on the 716 patients with ACL injury who received primary ACL reconstruction surgery and met the selection criteria between January 2012 and September 2018. After a mean follow-up period of 7.6 years (range, 4-10 years), 65 patients (9.1%) experienced contralateral ACL injury (injured group) and 651 patients (90.9%) did not (uninjured group). There was no significant difference in age, body mass index, and preoperative Lachman test degree between groups ( P>0.05). However, the proportion of female in the injured group was significantly higher than that of male ( P<0.05), and the preoperative posterior tibial slope (PTS) was significantly higher than that of the uninjured group ( P<0.05). Using the outcome of contralateral ACL injury as the dependent variable, the clinical data of the patient was first used as the independent variable, and univariate COX regression was used to analyze the prognostic influencing factors. Then, the indicators with differences in univariate COX regression were used as the independent variable, and multivariate COX regression was used to analyze the independent risk factors affecting prognosis. Log-Rank (Mantel-Cox) test was used to test and analyze the occurrence time of contralateral ACL injury in patients of different genders; X-tile software was used to analyze the occurrence time of contralateral ACL injury in patients with different PTS using Log-Rank (Mantel-Cox) test and PTS cut-off values.Univariate COX regression analysis showed that gender and PTS were influence factors for contralateral ACL injury ( P<0.05); further multivariate COX regression analysis showed that female and increased PTS were independent risk factors for contralateral ACL injury ( P<0.05). The Log-Rank (Mantel-Cox) test results showed that the contralateral ACL injury occurred in female at 8.853 (8.600, 9.106) years, which was significantly shorter than that in male [9.661 (9.503, 9.819) years] ( χ2=20.323, P<0.001). Using X-tile software to analyze the cut-off value of PTS, it was found that the cut-off value of PTS for contralateral ACL injury was 10.92°. According to the Log-Rank (Mantel-Cox) test, it was found that the contralateral ACL injury occurred in 5.762 (4.981, 6.543) years in patients with PTS≥10.92°, which was significantly shorter than patients with PTS<10.92° [9.751 (9.650, 9.853) years]( χ2 =302.479, P<0.001).Female and PTS≥10.92° after primary ACL reconstruction are independent risk factors for contralateral ACL injury.探讨初次前交叉韧带（anterior cruciate ligament，ACL）重建术后发生对侧ACL损伤的危险因素。.回顾分析2012年1月—2018年9月收治且符合选择标准的716例接受初次ACL重建术治疗的ACL损伤患者临床资料，经4～10年（平均7.6年）随访，其中发生对侧ACL损伤65例（9.1%，损伤组），未发生对侧ACL损伤651例（90.9%，未损伤组）。两组患者年龄、身体质量指数、术前Lachman试验分度比较差异均无统计学意义（ P>0.05）；但损伤组女性比例高于男性（ P<0.05），术前胫骨平台后倾角（posterior tibial slope，PTS）高于未损伤组（ P<0.05）。以是否发生对侧ACL损伤结局为因变量，先将患者临床资料作为自变量，采用单因素COX回归分析预后影响因素；再将患者单因素COX回归分析有差异的指标作为自变量，采用多因素COX回归分析影响预后的危险因素。采用Log-Rank（Mantel-Cox）检验，分析不同性别患者对侧ACL损伤的发生时间；采用X-tile软件对PTS截断值分析，采用Log-Rank（Mantel-Cox）检验分析不同PTS患者对侧ACL损伤的发生时间。.单因素COX回归分析显示，性别、PTS是对侧ACL损伤的影响因素（ P<0.05）；进一步行多因素COX回归分析显示，女性和PTS增大是对侧ACL损伤的危险因素（ P<0.05）。Log-Rank（Mantel-Cox）检验示，女性对侧ACL损伤发生 ［8.853（8.600，9.106）年］ 早于男性 ［9.661（9.503，9.819）年］（ χ2=20.323， P<0.001）。采用X-tile软件对PTS截断值分析发现，PTS对对侧ACL损伤发生的截断值为10.92°。经Log-Rank（Mantel-Cox）检验发现，PTS≥10.92° 的患者对侧ACL损伤发生 ［5.762（4.981，6.543）年］ 早于PTS<10.92° 者 ［9.751（9.650，9.853）年］（ χ2=302.479， P<0.001）。.初次ACL重建术后女性和PTS≥10.92° 是发生对侧ACL损伤的危险因素。.