Association between Kaplan fiber injury and anterolateral tibial subluxation in patients with anterior cruciate ligament injury.

BACKGROUND

Kaplan fibers (KFs) are critical stabilizers of the knee, yet their role in anterior tibial subluxation of the lateral compartment (ATSLC) in anterior cruciate ligament (ACL) injury remains unclear. This study is to determine whether KF injury is independently associated with increased ATSLC on magnetic resonance imaging (MRI) in patients with an injured ACL, and to identify risk factors for high-grade ATSLC (≥ 4.5 mm).

PATIENTS AND

METHODS

This retrospective study enrolled 132 patients with ACL injury who underwent MRI within 12 weeks of trauma. MRI was used to evaluate the integrity of the ACL, KFs, anterolateral ligament (ALL), bony morphology, and ATSLC. Two trained observers independently assessed all images using standardized criteria. Agreement between observers was calculated using standard reliability metrics. Multivariable linear regression was performed to evaluate the independent association between KF injury and ATSLC. Logistic regression and receiver operating characteristic analysis were used to identify predictors of high-grade anterior tibial subluxation (≥ 4.5 mm) in patients with combined ACL and anterolateral complex injuries.

RESULTS

Of the 132 patients, 35.6% had KF injuries. These patients exhibited higher rates of ALL injury and distinct bony morphologic features. KF injury independently explained 15.1% of anterior tibial subluxation variability (P < 0.001). In patients with combined anterolateral complex injuries, increased lateral femoral condyle width ratio was identified as an independent predictor of high-grade subluxation.

DATA

CONCLUSION

KF injury is independently associated with greater anterior tibial subluxation, suggesting a key role in post-traumatic knee instability. Specific femoral anatomical feature may further predict high-risk cases.

LEVEL OF EVIDENCE: Level IV.