Anterior tibial translation in anterior cruciate ligament-deficient knees is increased regardless of tear location and independently associated with early-to-intermediate injury chronicity.
TL;DR
It is suggested that ACL tear location alone should not be seen as a clinical predictor of anterior sagittal knee stability after ACL injury and only chronicity remained independently associated with ATT-SSD after adjustment.
Abstract
Purpose
To determine whether anterior cruciate ligament (ACL) tear type and injury chronicity influence preoperative instrumented anterior tibial translation side-to-side difference (ATT-SSD) in patients undergoing primary ACL surgery, and, as a secondary aim, to evaluate the association between concomitant meniscal tears and ATT-SSD.
Methods
This retrospective single-surgeon study included 521 patients who underwent surgery for ACL injury between October 2019 and January 2026. Preoperative ATT-SSD was measured using a Lachmeter® digital arthrometer, and ACL tears were classified arthroscopically according to the modified Sherman classification. Injuries were categorized by time to first visit as acute (<28 days), subacute (28-90 days) or chronic (>90 days). Associations between tear type, chronicity, meniscal repair and ATT-SSD were assessed using analysis of variance, subgroup comparisons, interaction analysis and multivariable linear regression.
Results
ATT-SSD differed across tear-type groups (p = 0.006), with Types III-V tears demonstrating a 0.5-mm greater mean ATT-SSD than Type I tears (p = 0.004), while Type II tears did not differ significantly from either group. Acute injuries showed greater ATT-SSD than subacute and chronic injuries (4.6 ± 1.5 vs. 4.2 ± 1.5 and 4.0 ± 1.5 mm; p = 0.005). The tear type × chronicity interaction was not significant (B = 0.019, p = 0.951). ATT-SSD was higher in patients undergoing medial meniscus repair. In multivariable regression, only chronicity remained independently associated with ATT-SSD (B = -0.205, p = 0.032), whereas ACL tear location was not independently associated with ATT-SSD.
Conclusions
Mean ATT-SSD remained above the clinically meaningful threshold of ≥3 mm across all ACL tear types. Although small differences in ATT-SSD were observed according to tear location and early-to-intermediate injury chronicity in unadjusted analyses, only chronicity remained independently associated with ATT-SSD after adjustment. These findings suggest that ACL tear location alone should not be seen as a clinical predictor of anterior sagittal knee stability after ACL injury. LEVEL OF EVIDENCE Level III, retrospective cohort study.