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Purpose: To compare the values and the relationship of tibial tubercle lateralization measurements between computerized tomography (CT) and magnetic resonance imaging (MRI). Methods: Sixty patients with patellar dislocation who underwent both CT and MRI of the same knee joint from November 2021 to February 2022 were included in our study. The intraclass correlation coefficient (ICC) and Bland–Altman analysis were performed to evaluate the reliability of tibial tubercle–trochlear groove (TT–TG), tibial tubercle–Roman arch (TT–RA), and tibial tubercle–posterior cruciate ligament (TT–PCL) distance measurements. The values of CT and MRI measurements using the same bony landmarks were compared for the difference. Pearson correlation analysis and linear regression analysis were performed to assess the correlation between CT and MRI measurements. Finally, the estimated values obtained from the regression equation were compared with the actual values obtained from the radiological measurement to evaluate the accuracy of the equations. Results: A total of 60 patients with patellar dislocation who underwent both CT and MRI of the same knee joint were included in this study. The included measurements showed excellent agreement with ICCs > 0.9. TT–TG distance measured on CT (19.5 ± 5.1 mm) had a mean of 7.1 mm higher than that on MRI (12.4 ± 4.7 mm) (P < 0.001). The mean value of TT–RA distance was 22.5 ± 3.7 mm on CT and 16.7 ± 4.9 mm on MRI (P < 0.001), showing a mean difference of 5.8 mm. The values of TT–TG distance measured by CT and MRI were significantly correlated (R = 0.5, P < 0.001). The values of TT–RA distance between these two modalities showed a better correlation than that of TT–TG distance (R = 0.6, P < 0.001). The interchange values of TT–TG distance and TT–RA distance between CT and MRI can be obtained using regression equations (TT–TG distance: y = 0.6x + 12.3; TT–RA distance: y = 0.5x + 14.4). Conclusion: The values of tibial tubercle lateralization measured by MRI may be underestimated compared with those measured by CT. Although the values measured on CT and MRI are not equivalent, the value in the other modality can be estimated. Therefore, an additional CT scan for tibial tubercle lateralization evaluation may not be necessary. Level of evidence: Level II. [ABSTRACT FROM AUTHOR]

Background: Femoral torsion can be evaluated from different femoral segments. The pathological thresholds for femoral torsion of different segments and the influence of segmental femoral torsion on patellofemoral alignment remain unknown. Purpose: To compare femoral torsion between patients with recurrent patellar dislocation and healthy individuals, to determine the statistical physiological range and pathological thresholds of femoral torsion in different segments, and to investigate the influence of femoral torsion on patellofemoral malalignment. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We retrospectively reviewed the records of patients with patellar dislocation who received surgical treatment in our department between 2019 and 2020. Healthy participants were recruited as the control group. The control patients were asymptomatic and had no history of lower extremity disorders. The differences in femoral torsion between the study and control groups were compared. The diagnostic capacity of femoral torsion in different segments and their correlation with patellar tilt were investigated. The mean value and 95% CI of femoral torsion in different segments were established using data from healthy volunteers. Results: A total of 60 patients with patellar dislocation and 100 healthy volunteers were included in this study. The total, mid, and distal femoral torsion values differed significantly between the study and control groups (P <.01). Total femoral torsion had the highest diagnostic value (area under the receiver operating curve = 0.733). Total torsion (r = 0.432; P <.001), mid torsion (r = 0.242; P =.002), and distal torsion (r = 0.324; P <.001) showed significant correlations with patellar tilt. The pathological thresholds of excessive femoral torsion of the total, proximal, mid, and distal femoral segments were 24.73°, 46.68°, –6.55°, and 14.92°, respectively. Conclusion: Patients with patellar dislocation had greater femoral torsion than healthy individuals in multiple femoral segments. Excessive mid, distal, and total torsion was associated with more significant patellar tilt. [ABSTRACT FROM AUTHOR]