In females with anterior knee pain, the infratuberositary contribution to external tibial torsion increases with torsion severity and does not correlate with tibial tubercle lateralisation.

Purpose: To perform a segmental analysis of tibial torsion in females with refractory anterior knee pain (AKP) and investigate the relationship between external tibial torsion (ETT) and the position of the tibial tubercle (TT). Methods: All disabling AKP patient refractory to adequate physical therapy, that presented to our clinic between January 2013 and December 2024 were retrospectively reviewed. Inclusion criteria: (1) females, (2) ≥18 years old, (3) torsional CT scan performed for strictly clinical reasons. Patients were classified into three groups according to ETT: normal (≤30°), moderate (31°-40°), and severe (>40°). ETT was measured proximally and distally to the TT, and the contribution of distal tibial torsion (DTT) to total tibial torsion (TTT) was calculated. TT lateralisation (TTL) relative to the tibial plateau's maximum transverse diameter was measured. Statistical analysis for comparisons was conducted using one-way ANOVA with Bonferroni correction and Student's t-test. Correlations were assessed with Pearson's coefficient. To evaluate the association between TTT and the percentage of DTT, a linear regression analysis was performed. Inter-observer reproducibility was evaluated using the intraclass correlation coefficient. Statistical significance was set at p < 0.05. Results: A total of 197 tibial CT scans from 101 AKP females were analysed. The percentage of contribution of DTT to TTT was significantly higher in the severe group (35.2%, SD 11.5) compared to the moderate (22.1%, SD 12.1) and normal (18.2%, SD 16.7) groups (p < 0.01). A moderate correlation between TTT and DTT contribution was identified (R = 0.540, p < 0.001). Linear regression analysis indicated that ETT was a significant predictor of DTT contribution (p < 0.001). No significant correlation was found between TTL and ETT severity. Conclusion: The infratuberositary contribution to pathological ETT increases with the severity of the torsion. Moreover, the degree of ETT does not affect TTL. Level of Evidence: Level IV.