BACKGROUND Anterior tibial subluxation (ATS) in extension after anterior cruciate ligament (ACL) injury highlights an increased anterior position of the tibia relative to the femur. Recent studies demonstrated that subluxation is sometimes irreducible and the normal tibiofemoral relationship is not restored by ACL reconstruction (ACLR), which raises concerns regarding clinical outcomes after ACLR. HYPOTHESIS Excessive preoperative ATS in extension is associated with inferior knee stability after anatomic ACLR. STUDY DESIGN Cohort study; Level of evidence, 3. METHODS From March 2016 to January 2017, a total of 487 consecutive patients with clinically diagnosed noncontact ACL injuries who underwent primary anatomic ACLR were retrospectively analyzed. Of these patients, 430 met the criteria for inclusion in this study. Anterior subluxation of the lateral and medial compartments (ASLC and ASMC) in extension relative to the femoral condyles was measured on preoperative magnetic resonance imaging. Twenty patients (study group) who demonstrated excessive (>10 mm) ASLC and ASMC in extension were matched 1:2 to 40 participants (control group) who showed minimal or no (<3 mm) ASLC and ASMC in extension. The amount of ASLC and ASMC in extension relative to the femoral condyles at 2 years postoperatively was the primary outcome. Moreover, the Lysholm score, IKDC grade (International Knee Documentation Committee), and stability assessments (pivot-shift test and KT-1000 arthrometer side-to-side difference) were evaluated preoperatively and at the last follow-up visit. RESULTS The preoperative mean ASLC and ASMC in extension of the study group were both significantly larger than those of the control group (study group vs control group: ASLC, 13.5 mm vs 1.2 mm; ASMC, 12.4 mm vs 1.0 mm; P < .05). Moreover, patients in the study group showed significantly larger posterior tibial slope than the patients in the control group (17.8°± 2.5° vs 9.5°± 1.5°; P < .05). At the final follow-up visit, the mean ASLC and ASMC of the study group were 8.1 mm and 7.3 mm, which were significantly larger than those of the control group (ASLC, 0.9 mm; ASMC, 0.7 mm; P < .05). In addition, the study group showed inferior knee stability when compared with the control group in terms of both the pivot-shift test (study group vs control group: 2 grade 2, 10 grade 1, and 8 grade 0 vs 1 grade 1 and 39 grade 0; P < .05) and the KT-1000 arthrometer side-to-side difference (study group vs control group: 4.4 ± 1.2 mm vs 1.5 ± 0.6 mm; P < .05). Furthermore, the study group showed significantly lower mean Lysholm score (study group vs control group: 80.3 ± 6.3 vs 93.3 ± 4.3, P < .05) and IKDC grading results (study group vs control group: 3 grade C, 16 grade B, and 1 grade A vs 3 grade B and 37 grade A; P < .05) as compared with the control group. CONCLUSION In this short-term study, the excessive (>10 mm) preoperative ATS in extension after ACL injury was associated with inferior knee stability after anatomic ACLR.

中文翻译：

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解剖学上的前交叉韧带重建术后，过度的术前胫骨前半脱位过度与膝关节稳定性差有关。

背景技术在前十字韧带（ACL）损伤后，前胫骨半脱位（ATS）延伸突出显示胫骨相对于股骨的前部位置增加。最近的研究表明，半脱位有时是无法避免的，并且ACL重建（ACLR）无法恢复正常的胫股关系，这引起了对ACLR术后临床结局的担忧。假设术前ATS过度伸展与解剖ACLR后膝关节稳定性差有关。研究设计队列研究；证据级别，第3级。方法从2016年3月至2017年1月，回顾性分析了487例经临床诊断为非接触式ACL损伤的连续患者，这些患者均接受了原发性解剖ACLR。在这些患者中，有430名符合纳入本研究的标准。在术前磁共振成像中测量相对于股骨les延伸的外侧和内侧隔室（ASLC和ASMC）的前半脱位。20名患者（研究组）表现出过度（> 10毫米）ASLC和ASMC延伸，将1：2匹配到40名参与者（对照组），表现出极少或没有（<3毫米）ASLC和ASMC延伸。主要结果是术后2年相对于股骨dy延伸的ASLC和ASMC量。此外，术前和最后一次随访时评估了Lysholm评分，IKDC评分（国际膝关节文献委员会）和稳定性评估（枢轴位移测试和KT-1000关节压力计的左右差异）。结果研究组术前平均ASLC和ASMC均显着大于对照组（研究组与对照组：ASLC，13.5 mm vs 1.2 mm; ASMC，12.4 mm vs 1.0 mm; P <.05 ）。此外，研究组患者的胫骨后倾斜度明显大于对照组（17.8°±2.5°与9.5°±1.5°； P <.05）。在最后的随访中，研究组的平均ASLC和ASMC分别为8.1 mm和7.3 mm，显着大于对照组（ASLC为0.9 mm； ASMC为0.7 mm； P <.05）。 。此外，在枢轴移位测试方面，研究组与对照组相比，膝关节稳定性较差（研究组与对照组：2级2、10级1和8级0与1级1和39 0级； P <。05）和KT-1000关节流量计的左右差异（研究组与对照组：4.4±1.2 mm与1.5±0.6 mm; P <.05）。此外，研究组的平均Lysholm评分（研究组与对照组：80.3±6.3 vs 93.3±4.3，P <.05）和IKDC评分结果（研究组与对照组：C为3级，B为16级，与对照组相比，A级为1级，而B级为3级，A级为37级； P <.05）。结论在这项短期研究中，ACL损伤后术前ATS过度（> 10 mm）延伸与解剖ACLR后膝关节稳定性差有关。3±4.3，P <.05）和IKDC评分结果（研究组vs对照组：3级C，16级B和1级A与3级和37级A; P <.05）控制组。结论在这项短期研究中，ACL损伤后术前ATS过度（> 10 mm）延伸与解剖ACLR后膝关节稳定性差有关。3±4.3，P <.05）和IKDC评分结果（研究组vs对照组：3级C，16级B和1级A与3级和37级A; P <.05）控制组。结论在这项短期研究中，ACL损伤后术前ATS过度（> 10 mm）延伸与解剖ACLR后膝关节稳定性差有关。