PurposeThe proximal tibiofibular joint (PTFJ) is biomechanically related to the tibiofemoral joint and may influence load transmission across the knee. However, it remains unclear whether PTFJ morphology is associated with coronal knee phenotype, joint line obliquity, or both. This study aimed to radiologically evaluate the relationship between coronal knee alignment, joint line obliquity, and PTFJ morphology in patients with advanced knee osteoarthritis.MethodsThis retrospective study included 324 patients with Kellgren-Lawrence grade 3-4 knee osteoarthritis who underwent standing long-leg radiographs and knee computed tomography. Coronal alignment parameters (mHKA, aHKA) and joint line obliquity were assessed on radiographs. PTFJ morphology-including coronal and sagittal inclination angles, joint obliquity, axial morphology, joint contour, fibular height, and fibula/tibia moment arm ratio-was evaluated using CT images. Associations between coronal knee phenotype, joint line obliquity, and PTFJ parameters were analyzed using non-parametric tests and categorical analyses.ResultsPTFJ morphological classifications differed significantly across coronal knee phenotypes. Flat PTFJ morphology was more frequent in varus-aligned knees, whereas convex axial morphology predominated in valgus alignment. Sagittal PTFJ inclination angle, tibial plateau-fibular axis angle, and fibula/tibia moment arm ratio differed significantly among alignment groups. Joint line obliquity was associated with differences in sagittal PTFJ inclination, fibular height, and related angular parameters, while coronal PTFJ slope and joint obliquity did not differ significantly.ConclusionIn advanced knee osteoarthritis, PTFJ morphology is associated with coronal knee phenotype and joint line obliquity. These findings suggest that PTFJ morphology reflects the relative spatial relationship between the tibia and fibula rather than being solely a consequence of degenerative change, supporting a combined constitutional and load-related influence.
Erkurt et al. (Fri,) studied this question.