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Objectives and questions: To evaluate the relationship between tibiofemoral rotation (TFR) and patellofemoral alignment parameters before and after surgical stabilizing procedures and to determine whether realignment of the extensor apparatus induces a spontaneous reduction in TFR, supporting the concept of a dynamic biomechanical process.

Material and methods: A total of 142 patients undergoing surgical treatment for recurrent patellar instability were included (100 females, 42 males; mean age 24.5 ± 8.2 years). All patients underwent medial patellofemoral ligament (MPFL) reconstruction combined with thin-flap trochleoplasty; tibial tubercle osteotomy (TTO) was additionally performed when indicated. Patellofemoral parameters—trochlear bump, patellar tendon–trochlear groove angle (PT-TGA), sagittal tibial tuberosity–trochlear groove distance (sTTTG), and TFR—were assessed pre- and postoperatively. Correlation and multivariable regression analyses were performed to determine associations between TFR and alignment parameters. Subgroup analyses were conducted according to sex, with correction for multiple testing.

Results: All alignment parameters demonstrated significant postoperative reductions. The largest decrease was observed for trochlear bump (−4.07 mm, 95% CI −4.48 to −3.66; p < 0.001), followed by PT-TGA (−9.87°, 95% CI −11.9 to −7.81; p < 0.001), sTTTG (−5.53 mm, 95% CI −6.52 to −4.55; p < 0.001), and TFR (−1.38°, 95% CI −2.26 to −0.51; p = 0.002). Preoperatively, TFR scorrelated with PT-TGA (r = 0.513, p < 0.001) and with sTTTG (r = 0.197, p = 0.02) while no association with trochlear bump was observed (p=0.14). These associations persisted postoperatively (r = 0.297, p < 0.001; r = 0.263, p = 0.002), and PT-TGA and sTTTG remained independent predictors of TFR in multivariable models all p < 0.001). Preoperative trochlear bump values were higher in males (7.67 ± 1.95 mm vs. 6.00 ± 1.82 mm; p < 0.001), but no sex-specific differences were observed for TFR or for postoperative changes. No significant interaction effects were detected after correction.

Discussion and conclusions: TFR is significantly associated with axial patellofemoral alignment parameters. The postoperative reduction of TFR following realignment procedures suggests that tibiofemoral rotation may adapt secondary to correction of extensor apparatus alignment, supporting the concept of a dynamic rotational relationship.