Navigation of Short-stem Implants

摘要

An increasing demand for less traumatic total hip arthroplasty (THA), combined with a faster recovery period, has led to both minimally invasive surgical approaches and bone- and soft tissue preserving short-stem prostheses.The need for enhanced joint stability and high mobility after THA has led to navigated hip surgery with the use of modular necks to restore biomechanics.Morrey demonstrated good results with short-stem prostheses. The preservation of bone stock, reduced soft tissue trauma, facilitation of minimally invasive surgery with reduced blood loss, reduction of surgery time, shorter hospital stay, faster recovery time, and immediate stability under full weight are the goals of implanting short-stem prostheses. To achieve primary stability, the short-stem prosthesis has multipoint contact with cortical areasin the metaphyseal femur. Multipoint contact forces the prosthesis stem into a virtually preset implant position with only few possibilities for variation that can affect the biomechanics of the hip in terms of leg length and offset. The modular construction of the prosthesis decouples the stem position from the joint reconstruction, offering the possibility influencing joint geometry with greater variability and without compromising secure fixation in the femur.Navigation has proven to be a useful tool to achieve more precise positioning of THA implants. Another advantage of a modular implant is that the changes in the biomechanics of a hip are displayed and can be easily influenced intraoperatively. The suitability of a modular short stem to meet the expectations was evaluated in this study.