Sagittal femoral morphology is not associated with coronal alignment phenotypes: A radiographic analysis from the Brescia Knee Research Group.

Purpose: To evaluate the association between sagittal femoral morphology and coronal alignment phenotypes. It was hypothesised that sagittal femoral morphology is not associated with coronal phenotype classifications. Methods: This retrospective study analysed a prospectively maintained institutional database including patients who underwent primary total knee arthroplasty (TKA) between January 2021 and November 2022. Preoperative radiographic assessment included standardised lateral and full-length weight-bearing radiographs. Coronal alignment parameters included mechanical hip-knee-ankle angle (mHKA), arithmetic hip-knee-ankle angle (aHKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA) and joint line obliquity (JLO). Sagittal femoral morphology was assessed using anterior femoral offset (AFO), posterior femoral offset (PFO) and anteroposterior femoral size (AP size). Patients were classified according to the coronal plane alignment of the knee (CPAK) classification and functional knee phenotypes (FKPs). Results: A total of 212 patients were included. No significant associations were observed between sagittal femoral morphology and coronal phenotypes. AFO, PFO and AP size did not differ across CPAK types ( Conclusions: Sagittal femoral morphology is not associated with coronal alignment phenotypes, indicating that sagittal and coronal knee characteristics represent independent anatomical domains. Coronal phenotype classifications alone may therefore be insufficient to characterise patient-specific femoral morphology during preoperative TKA planning. Level of Evidence: Level III.