A unique multi-planar external fixator developed for hip distraction

摘要

Introduction: Legg-Calve-Perthes disease (LCPD) is a form of hip joint disorder, in which avascular necrosis leads to bone softening and fragmentation. It results in deformity of the femoral head and collapse of the functioning hip joint, including subluxation and loss of range of motion. Persistent subluxation would lead to permanent deformity. Hip distraction is used to distract the hip joint in order to restore the normal anatomy by reducing subluxation and containment of the hip in skeletally immature patient. It is intended that by removing mechanical loading on hip joint, there would improve synovial circulation for better healing. However, the current distractor only allows one direction of movement (i.e. hip flexion). This limitation greatly impairs the mobility of the patients. In our study, a new multi-planar external fixator is designed and tested on cadaveric specimen. It allows two planes of motion (hip flexion/extension and abduction/adduction) without dislocation of bone.