Relationship between patellofemoral finite helical axis and femoral trans-epicondylar axis using a static magnetic resonance-based methodology

Abstract Background To manage patellofemoral joint disorders, a complete understanding of the in vivo kinematics is critical. However, as one parameters kinematics, location and orientation finite helical axis (FHA) remains unclear. The purpose this study to quantify patellar FHA, both non-invasively at various flexion angles, evaluate relationship FHA trans-epicondylar (TEA). Methods magnetic resonance (MR) images 18 unilateral knees were collected full extension, 30°, 60°, 90°, maximum angle knee flexion. Three-dimensional models different angles created using MR images, then used calculate tracking with spline interpolation algorithm. By coordinate system based on TEA, was quantified. Six concerning analysed. Results average drew an L-shaped midsagittal plane moving from posteroinferior anterosuperior side TEA Before 90° flexion, rotational radius decreased slightly, value 5.65 ± 1.09 cm. During 20° between approximately 10° that coronal maintained about 0°, while level fluctuated ? 10°. Conclusions This quantitatively reported continuous direction during close but not coincident femoral orientation, slightly These findings could provide clear for further studies difference among types foundation application surgical evaluation, preoperative planning prosthesis design, thereby assisting diagnosis treatment disorders.