Arthroscopy - 2026-03-22 - Journal Article
Increased Preoperative Lateral Anterior Tibial Subluxation by Magnetic Resonance Imaging Is Associated With Increased Knee Laxity After Anatomical Anterior Cruciate Ligament Reconstruction.
Murakami R, Taketomi S, Yamagami R, Kono K, Kobayashi T, Murakami T, Tanaka S
Topics
Key Takeaway
Preoperative lateral ATS on MRI independently predicts postoperative lateral ATS (β=0.313, p<0.001), and postoperative lateral ATS correlates with residual pivot shift after anatomical ACL reconstruction.
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Summary
This study examined whether preoperative MRI-measured anterior tibial subluxation (ATS) predicts postoperative ATS and residual instability after anatomical ACL reconstruction using BPTB or double-bundle hamstring grafts. Postoperative lateral ATS increased significantly versus preoperative values (3.2 vs. 2.5 mm, p=0.01), and multivariate regression identified preoperative lateral ATS as the sole independent predictor of postoperative lateral ATS (β=0.313, p<0.001). Female sex, chronic ACL deficiency >3 months, medial meniscus lesions, and preoperative medial ATS independently predicted postoperative medial ATS, which correlated with worse Lysholm scores and anterior laxity.
Key Limitation
Retrospective design with mixed graft types prevents determination of whether graft selection modifies the relationship between preoperative ATS and postoperative instability.
Original Abstract
PURPOSE
To clarify the correlation between postoperative anterior tibial subluxation (ATS) and clinical outcomes and identify the factors that influence postoperative ATS following anatomical anterior cruciate ligament (ACL) reconstruction.
METHODS
Data of patients who underwent primary anatomical ACL reconstruction between 2012 and 2022 and postoperative magnetic resonance imaging over 2 years after surgery were enrolled. The ATS values for the medial and lateral compartments were measured on pre- and postoperative magnetic resonance imaging. Correlations between the postoperative clinical outcomes and postoperative ATS were analyzed. Multivariate regression analysis was performed to reveal the independent risk factors for the postoperative ATS among patients' demographic data and parameters that correlated with the postoperative ATS.
RESULTS
Overall, 208 patients with follow-up duration of at least 2 years were included. Postoperative lateral ATS was significantly increased compared with its preoperative counterparts (2.5 ± 4.1 mm, 95% confidence interval [CI] [2.0-3.1] vs. 3.2 ± 3.1 mm, 95% CI [2.8-3.7], P = .01), whereas no significant difference was found in the medial ATS (0.7 ± 2.9 mm, 95% CI [0.3-1.1] vs. 0.8 ± 2.2 mm, 95% CI [0.5-1.1], P = .55). Postoperative medial ATS was significantly correlated with the postoperative Lysholm score (r = -0.19, P < .01), pivot shift test (r = 0.14, P = .04), and anterior laxity (r = 0.15, P = 0.03), and the postoperative lateral ATS with the postoperative pivot shift test (r = .14, P = .04). Multivariate regression analysis revealed female sex (estimate = 0.799, 95% CI [0.267-1.331], P = .004), chronic ACL deficiency (>3 months from injury) (estimate = 0.594, 95% CI [0.047-1.140], P = .033), medial meniscus lesions ((estimate = 0.627, 95% CI [0.076-1.178], P = .026), and preoperative medial ATS (estimate = 0.394, 95% CI [0.292-0.495], P < .001) as independent risk factors for postoperative medial ATS and the preoperative lateral ATS (estimate = 0.313, 95% CI [0.193-0.432], P < .001) as an independent risk factor for postoperative lateral ATS.
CONCLUSIONS
Greater preoperative ATS predicted increased postoperative ATS, which was associated with residual postoperative knee instability after anatomical ACL reconstruction using bone-patellar tendon-bone and double-bundle hamstrings tendon grafts with suspensory fixation.
LEVEL OF EVIDENCE
Level IV, retrospective case series.