Knee Osteoarthritis (KOA) Severity Influences Proximal Femoral Biomechanics and Predicts Pertrochanteric Fracture Instability: A Retrospective Radiographic Study

Background and Objectives: Intertrochanteric hip fractures (ITFs) are common in older adults and frequently coexist with knee osteoarthritis (KOA). Although both conditions share key biomechanical risk factors, the specific relationship between KOA severity and ITF stability has not been well defined. Recent evidence suggests that degenerative knee changes may alter lower-limb load distribution and increase susceptibility to unstable fracture patterns. This study evaluated whether KOA severity, graded using the Kellgren–Lawrence (KL) system, is associated with ITF stability according to the 2018 AO/OTA classification. Materials and Methods: A retrospective observational study was conducted on 138 patients with IHFs treated between 2018 and 2023. KOA severity was assessed using KL grades I–IV on non-weight-bearing anteroposterior knee radiographs. Lateral wall thickness (LWT) was measured using the Hsu method, with