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Updated: May 9, 2026
Athymic Rat Model for Evaluation of Engineered Anterior Cruciate Ligament Grafts
Published on: March 26, 2015
Graft orientation using the over-the-top technique in anterior cruciate ligament reconstruction: Magnetic resonance
Ying Ren Mok1, Alberto Grassi2,3, Giulio Maria Marcheggiani Muccioli2,3
1Department of Orthopaedic Surgery National University Hospital Singapore Singapore.
Purpose:
To quantify sagittal and coronal inclination angles following over-the-top (OTT) anterior cruciate ligament (ACL) reconstruction using magnetic resonance imaging (MRI), to compare these measurements with the native ACL, and to evaluate graft alignment relative to the European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) consensus.
Methods:
Thirty-five patients underwent single-bundle OTT ACL reconstruction combined with lateral plasty and underwent postoperative MRI evaluation at a minimum of 6 months. The reference group consisted of 28 patients with knee pain and an intact ACL on MRI. Sagittal and coronal inclination angles were measured using standardised tibial-axis-based MRI definitions. Measurements were performed independently by two examiners, and mean values were used for analysis. Group comparisons were conducted using independent-samples t-tests. Interexaminer reliability was assessed using intraclass correlation coefficients (ICC).
Results:
OTT reconstruction demonstrated a mean sagittal inclination angle (SIA) of 53.2° ± 5.1° and a mean coronal inclination angle (CIA) of 71.3° ± 5.9°. Compared with the native ACL cohort, OTT reconstructions showed significantly greater sagittal (mean difference 3.6°, p = 0.007) and coronal (mean difference 8.2°, p < 0.001) inclination angles. Most reconstructions fell within ESSKA consensus sagittal (<60°) and coronal (<75°) MRI thresholds (85.7% and 71.4%, respectively). Interexaminer agreement was excellent for both sagittal and coronal measurements (ICC > 0.90).
Conclusion:
OTT ACL reconstruction produces graft inclination angles that differ significantly from native ACL orientation but frequently fall within consensus-recommended MRI thresholds for sagittal alignment. MRI-based inclination assessment provides objective structural characterisation of this technique and complements previously reported long-term clinical outcomes. However, these imaging findings do not establish full anatomic replication or clinical equivalence.
Level Of Evidence:
Level IV, case series.
