A Robotic Model of Hip Dislocation Potential: Total Hip Arthroplasty Versus Femoral Head Resurfacing
Hip dislocation often results from neck impingement and subsequent subluxation. Having a model to study impingent-free range of motion (ROM) and dislocation potential at the impingement postures can elucidate the contribution to joint stability of prosthetic design, component position, anatomical variables, and biomechanical factors. Much controversy surrounds the resurgence of femoral head resurfacing (FHR) and its biomechanical implications of retaining the femoral neck, particularly its head-neck ratio. We have developed a dynamic cadaveric robotics model that functions in real time under load-control parameters to recreate in vivo hip mechanics. This study specifically identifies and compares the impingent-free ROM and a stability index value that quantifies the dislocation potential in the native hip, femoral head resurfacing and total hip replacement (size 28, 36mm femoral heads).