2025 ISAKOS Biennial Congress ePoster
Risk Factors For Residual Postoperative Anterior Tibial Subluxation After Anatomical Anterior Cruciate Ligament Reconstruction: A Two-Year Follow-Up Study
Ryo Murakami, MD, Bunkyo, Tokyo JAPAN
Shuji Taketomi, MD, PhD, Tokyo JAPAN
Ryota Yamagami, MD, Tokyo JAPAN
Kenichi Kono, MD, PhD, Minato, Tokyo JAPAN
Kohei Kawaguchi, MD, PhD, Tokyo JAPAN
Takahiro Arakawa, MD, Bunkyo-Ku, Tokyo JAPAN
Takashi Kobayashi, MD, Tokyo JAPAN
Tomoki Murakami, MD, Tokyo JAPAN
Sakae Tanaka, MD, PhD, Tokyo JAPAN
Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, JAPAN
FDA Status Not Applicable
Summary
ACL deficiency chronicity and preoperative ATS are correlated with residual postoperative medial and lateral ATS, respectively.
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Abstract
Objective
Anterior cruciate ligament (ACL) injury results in anterior translation and anterolateral rotatory instability of the tibia. ACL insufficiency causes the tibia to shift anteriorly relative to the femur due to the posterior tibial slope (PTS) and a failure to restrain anterior tibial translation. Static anterior tibial subluxation (ATS) increases as the time between injury and surgery extends. The ACL plays a critical role in restraining anterior knee laxity and maintaining the static position between the femur and tibia in the sagittal plane. Therefore, it is crucial to assess both dynamic instability and the static tibiofemoral relationship while evaluating dynamic instability. However, most studies have focused on preoperative ATS, and the causes of residual ATS after anatomical ACL reconstruction remain unclear. This study aimed to determine the factors influencing postoperative ATS after anatomical ACL reconstruction.
Methods
This study included 208 patients (98 females and 110 males; mean age: 30.3 ± 12.6 years) who underwent primary anatomical ACL reconstruction using either a bone-patellar tendon-bone autograft or a hamstrings tendon autograft, with postoperative magnetic resonance imaging (MRI) examination 2 years postoperatively. Pre- and postoperative MRIs were conducted to measure the ATS values for the medial and lateral compartments while the patients relaxed their quadriceps in the supine position, without anesthesia. The correlation between surgical findings, radiographic factors, clinical factors, and postoperative ATS was analyzed. Multivariate regression analysis was conducted to determine independent risk factors for the postoperative medial and lateral ATS among patients’ demographic data and parameters that correlated with the postoperative ATS in the correlation analyses.
Results
The postoperative medial and lateral ATS were 0.9 ± 2.2 and 3.3 ± 3.2 mm, respectively. The postoperative medial ATS was significantly correlated with body mass index, sex, medial meniscus lesions, cartilage lesions, ACL deficiency chronicity, medial PTS angle, and preoperative medial ATS. The postoperative lateral ATS was significantly correlated with sex, graft, ACL deficiency chronicity, and preoperative lateral ATS. Multivariate regression analysis identified female sex (P < 0.01), ACL deficiency chronicity (P = 0.04), and preoperative medial ATS (P < 0.01) as independent risk factors for postoperative medial ATS. For the postoperative lateral ATS, ACL deficiency chronicity (P = 0.04) and preoperative lateral ATS (P < 0.01) were identified as independent risk factors.
Conclusion
ACL deficiency chronicity and preoperative ATS are correlated with residual postoperative medial and lateral ATS, respectively. Additionally, being female is a risk factor for residual postoperative medial ATS.