The Preoperative Sagittal Tibial Tubercle-Trochlear Groove Distance Predicts Postoperative Outcome in Patients Undergoing Trochleoplasty: Patellofemoral

Objectives: The sagittal tibial tubercle–trochlear groove (sTTTG) distance has emerged as a novel parameter in assessing patellofemoral malalignment. Its role in predicting postoperative outcomes especially after trochleoplasty remains unclear. This study aimed to evaluate the association between sTTTG and patient-reported outcomes following medial patellofemoral ligament reconstruction (MPFLR) and deepening trochleoplasty. Methods: A retrospective analysis was conducted on 101 patients (male/ female 29/72; 22.7 ± 6.6 years) who underwent combined MPFLR and trochleoplasty for recurrent lateral patellar instability with high-grade trochlear dysplasia. The sTTTG distance was measured on preoperative axial T2-weighted magnetic resonance imaging (MRI) sequences. Specifically, the measurement involved identifying the nadir of the anterior trochlear cartilage and the most prominent point of the tibial tubercle. A line was drawn parallel to the posterior condylar axis at each of these points, and the perpendicular distance between these lines was calculated to determine the sTTTG distance. Postoperative outcomes assessed included pain levels (Numerical Rating Scale), subjective knee function, and the Banff Patellofemoral Instability Instrument 2.0 (BPII 2.0) score. Univariable and multivariable linear regression analyses were performed, adjusting for age, BMI, Caton–Deschamps index, Dejour classification, and TT-TG. Results: Univariable analysis demonstrated that a higher preoperative sTTTG was significantly associated with improved postoperative subjective function (β=0.088, p=0.014), lower pain levels ( β = – 0.10, p=0.048), and higher BPII 2.0 scores ( β=0.98, p=0.019). These associations remained statistically significant after adjusting for confounding variables (Function: β=0.096, p=0.011; Pain: β=–0.11, p=0.044; BPII 2.0: β=0.91, p=0.037). The multivariable models exhibited moderate explanatory power, with adjusted R² values ranging from 0.03 to 0.06. Conclusion: The preoperative sTTTG distance is a significant and independent predictor of postoperative patient-reported outcomes in individuals undergoing deepening trochleoplasty. Higher sTTTG values were associated with better functional recovery, reduced pain, and enhanced patellofemoral quality of life. These findings support the incorporation of sagittal alignment parameters into preoperative evaluations and risk stratification for patients with severe trochlear dysplasia.