Femoral Anteversion Is Related to Tibial Tubercle-Trochlear Groove Distance in Patients with Patellar Dislocation

Purpose: To evaluate the potential relationship between the tibial tubercle-trochlear groove (TT-TG) distance and the femoral anteversion of different segments of the femur in patients with patellar dislocation. Methods: A total of 60 patients with a diagnosis of patellar dislocation were included in our study. Patients with previous knee surgeries, previous fractures, or lack of necessary radiologic examinations were excluded from our study. The data of computed tomography scanning within a week before the surgery was used to measure the TT-TG distance, total anteversion, proximal anteversion, diaphyseal anteversion, distal anteversion, and tibial torsion. All the data were obtained from the picture archiving and communication system (PACS) workstation. The Pearson correlation analysis was performed to confirm the potential relationship between TT-TG distance and femoral anteversion of different segments. The intraclass correlation coefficient was used to assess the interobserver reliability of measurements. Results: The TT-TG distance was significantly correlated with the diaphyseal anteversion (r = -0.305, P = 0.008) and distal anteversion (r = 0.365, P = 0.004). The total anteversion was associated with proximal anteversion (r = 0.392, P = 0.02) and diaphyseal anteversion (r = 0.631, P < 0.001). The intraclass correlation coefficient showed the measurements of included parameters were presented with excellent agreement. Conclusion: Our study showed that patients with high diaphyseal anteversion and distal anteversion tend to had a higher TT-TG distance but the value of total and proximal femoral anteversion were independent of the value of TT-TG distance.