Enlarged tibial eminence may be a protective factor of anterior cruciate ligament

The relationship of distal femur and proximal tibia morphology with anterior cruciate ligament injuries

PURPOSE

The study aims to determine the correlations between the anatomical structures of the distal femur and proximal tibia associated with the anterior cruciate ligament (ACL).

METHODS

Bilateral extremities of 293 patients [143 ACL-ruptured, 150 ACL-intact] (all male) were included in the study. Femoral bi-condylar width (BCW), intercondylar notch width (NW) in the distal femur, proximal tibia width (TW), and tibial eminence width (EW) parameters were measured in the proximal tibia. Indexes are calculated as intercondylar notch width index (NWI) = NW/BCW, tibial eminence width index (EWI) = EW/TW.

RESULTS

BCW, NW, TW, and EW measurements were lower in the ACL-ruptured group, but the difference was statistically significant only in the NW (p = 0.009) and TW (p = 0.005) measurements. There was no difference between groups in the NWI. The EWI parameters were calculated higher in the ACL-ruptured group, and the difference was statistically significant (p = 0.02). In both groups, there were very strong correlations between BCW and TW (ACL-ruptured r = 0.820, ACL-intact r = 0.877) and between NW and NWI (ACL-ruptured r = 0.862, ACL-intact r = 0.852), also EW and EWI in ACL-intact group (r = 0.947).

CONCLUSIONS

The NW and TW measurements may give an idea about injury risk or prevention in morphological measurements. Correlations also show that the femur and tibia should consider together for ACL injuries.

Measurement of Medial Tibial Eminence Dimensions for the Clinical Evaluation of ACL-Injured Knees: A Comparison between CT and MRI

Anterior cruciate ligament (ACL) injuries commonly lead to translational and rotational tibiofemoral instability. The morphology of the medial tibial eminence (MTE) has received increased attention regarding its role in tibiofemoral stability in ACL-injured knees. Therefore, quantification of MTE dimensions on clinical imaging may help clinicians predict knee stability after ACL injury. Although magnetic resonance imaging (MRI) is routinely obtained in patients with ACL injuries, whether the dimensions of the MTE can be accurate quantified on MRI is unknown. The purpose of this study was to assess the degree of correlation between measurements of MTE height and width on computed tomography (CT) versus MRI. An institutional picture archiving and communication system imaging database was used to identify patients aged between 15 and 60 years who received concurrent MRI and CT of the same knee within a 1-year interval. Knees with significant arthrosis, deformity, intraarticular fracture, or hardware-related artifact that obscured visualization of the MTE were excluded. Mean differences and interstudy agreement between CT and MRI MTE measurements were compared using concordance correlation coefficient (r _c) and Bland-Altman analysis. A total of 41 knees in 38 patients (mean age, 37 years; 82% male) were analyzed. Interrater reliability for CT and MRI measurements was high (intraclass correlation coefficient = 0.740-0.954). On coronal CT and MRI, mean MTE height measurements were 10.4 ± 1.9 and 10.4 ± 1.8 mm, respectively; mean MTE width measurements were 14.6 ± 3.6 and 14.2 ± 3.0 mm, respectively. On sagittal CT and MRI, mean MTE height measurements were 11.6 ± 1.7 and 11.7 ± 1.7 mm, respectively; mean MTE width measurements were 36.5 ± 4.8 and 36.2 ± 5.0 mm, respectively. Good agreement was observed between CT and MRI measurements of MTE height and width on coronal and sagittal planes (r _c = 0.947-0.969). Measurements of MTE height and width were similar on MRI relative to CT on both coronal and sagittal planes. MRI may be suitable for characterizing the dimensions of the MTE when clinically evaluating patients with ACL injuries, potentially allowing for individualized patient care.