Associated Anatomic Abnormalities in Patients Undergoing Rotational Tibial Osteotomies for Patellofemoral Pathology and Implications for the Level of Correction.

Purpose: Tibial rotational deformity is a known risk factor for patellofemoral joint (PFJ) disorders. However, it is commonly associated with other abnormalities which affect the PFJ. The purpose of this study was to describe the prevalence of associated factors known to affect PFJ in patients undergoing rotational tibial osteotomy and their implication for the correction level.

Methods: All patients with PFJ disorder, who underwent rotational tibial osteotomy between July 2009 and February 2020, were included. Patients were excluded if there were no preoperative computed tomography (CT)/magnetic resonance imaging (MRI). Scans were analyzed by 2 observers. Parameters of interest were femoral version, tibial torsion, trochlear dysplasia, lateral trochlear inclination (LTI), tibial tuberosity-trochlear groove (TT-TG) distance, Insall-Salvati (IS), and Caton Deschamps Index (CDI).

Results: The search resulted in 80 knees, which had a mean femoral version of 21.0 ± 11.7, tibial torsion of 45.9 ± 9.1, TT-TG of 18.3 ± 5.5, and LTI of 11.4 ± 14.7. In total, 42.5% had TT-TG value of ≥ 20 mm. Patella alta/baja was found in 54% based on CDI or IS >1.2 and <0.8. High-grade trochlear dysplasia was found in 25%. In total, 29% had a tibial torsion abnormality but normal TT-TG and patella height. In total, 18% had abnormal TT-TG but normal patellar height.

Conclusion: Based on the associated abnormalities of patella height and tubercle lateralization, 18% of the population were suitable for supratubercle osteotomy, and 29% of patients were suitable for diaphyseal or distal tibial osteotomy. A tibial tubercle osteotomy was required in 54% of patients, making a through-tubercle approach the most appropriate option for most patients.

Level of evidence: Radiological cross-sectional study.