Female Sex Is Independently Associated With Greater Sagittal Tibial Tubercle‐Trochlear Groove Distance and Patellar Tilt in High‐Grade Trochlear Dysplasia

Purpose To assess sex‐related differences in patellofemoral (PF) anatomy among patients with PF instability and high‐grade trochlear dysplasia (Dejour types B‐D). Methods Consecutive patients with symptomatic PF instability and high‐grade trochlear dysplasia (Dejour types B‐D) who were scheduled for surgical treatment between January 2010 and December 2020 and had available preoperative radiographs and magnetic resonance imaging were retrospectively identified at a single center. Patients with normal trochlear morphology, type A dysplasia, missing preoperative magnetic resonance imaging, or prior osseous procedures were excluded. Standardized magnetic resonance imaging‐based measurements were obtained for trochlear morphology, tibial tubercle position, and patellar geometry. Depending on data distribution, parametric or nonparametric tests were used to compare sexes. Multivariate linear mixed‐effects models were performed to calculate regression coefficients ( B ) with 95% confidence intervals, adjusting for patient clustering, age, body height, supratrochlear spur height, Caton‐Deschamps index, sulcus depth, and tibiofemoral rotation. Results A total of 301 knees from 278 patients were analyzed; 192 knees (63.8%) were from female patients. The mean age was 22.6 ± 8.1 years (range, 11‐50 years), and the mean body mass index was 24.9 ± 5.5 (range, 16.4‐48.1). Distribution according to the Dejour classification was 40.5% type B, 31.2% type C, and 28.2% type D. Female patients showed smaller patellar width (37.9 ± 3.4 mm vs 41.3 ± 4.1 mm; P < .001) and thickness (16.8 ± 2.0 mm vs 18.5 ± 2.6 mm; P < .001), as well as greater patellar tilt (29.3° ± 10.7° vs 25.0° ± 10.8°; P = .001) and sagittal tibial tubercle‐trochlear groove (sTTTG) distance (9.9 ± 5.2 mm vs 8.4 ± 6.0 mm; P = .005). After adjustment for age and body height, differences in patellar width, patellar thickness, patellar tilt, and sTTTG remained significant. After additional adjustment for supratrochlear spur height, Caton‐Deschamps index, sulcus depth, and tibiofemoral rotation, patellar tilt ( B = 3.51°, P = .021) and sTTTG distance ( B = 2.36 mm, P = .004) remained greater in female patients. Conclusions Among patients with PF instability and high‐grade trochlear dysplasia, female sex was associated with greater patellar tilt and sTTTG distance after adjustment for age, body height, and relevant anatomical covariates. Level of Evidence Level III, prognostic retrospective comparative study.