Synonyms in a broader sense
short shaft prosthesis, cut prosthesis, mayo prosthesis, metha prosthesis, artificial hip joint, hip prosthesis, coxarthrosis, coxarthrosis
Definition
Within the framework of technical developments in orthopaedics, more and more prosthesis models are being developed with the aim of removing as little bone material as possible during hip surgery in order to find good conditions for securely anchoring a new prosthesis again in the event of a possible replacement operation. In addition to the cap prosthesis (McMinn prosthesis), the short shaft prosthesis is suitable for bone-saving implantation.
The operation of the short shaft prosthesis
The operation to insert a short shaft prosthesis is usually performed under general or partial anesthesia (spinal anesthesia). Access to the hip is preferably chosen via a tissue-conserving, minimally invasive approach, whereby the skin incision is made above the lateral hip joint (anterolateral access), thus avoiding the severing of hip muscles or tendons. This results in less pain postoperatively, fewer complications and faster rehabilitation.
Once the hip joint is exposed, the femoral head is first removed, the acetabulum is milled out and then replaced by an artificial one. The prosthesis stem is then inserted into the femur, secured and fitted with an artificial femoral head. Short stem prostheses are fixed without cement, so that they are initially “only” inserted or clamped into the still intact femur and gain further stability over the next few weeks as bone tissue grows into the roughened prosthesis surface.
In order to ensure that the insertion of the short shaft prosthesis is successful, an x-ray is taken in the operating room before the wound is closed, so that the correct fit of the prosthesis can be checked. A short shaft prosthesis can be implanted “minimally invasively”. This means that it is implanted through a small 6 – 10 cm skin incision.
The muscles can be spared as much as possible. The operation is performed as if a cementless hip endoprosthesis had been implanted. A short shaft prosthesis is a cement-free hip prosthesis which has a prosthesis shaft shortened by about 2/3 compared to a “classic prosthesis”.
The prosthesis is anchored in the upper part of the thigh bone (femur). The acetabular cup is implanted normally. As a rule, any acetabular cup can be combined with a short stem prosthesis.
