Hip Disarticulation and Hemipelvectomy
When the entire leg is removed by cutting through the hip joint, it is known as a hip disarticulation amputation. If part of the pelvis is also removed it is called a hemipelvectomy (hemi means half, but usually it is only a small portion of the pelvis that is lost). The prosthesis will include a replacement hip joint, knee joint and foot.
As there is no part of the leg remaining, the patient must bear their weight through the pelvis itself, by means a small shelf or seat directly below the ischial tuberosity (commonly known as the ‘sit bone’). In the hemipelvectomy the ischial tuberosity is removed as well, so the shelf is extended across to the other side (this is the biggest difference between the two types of amputation).
The socket of the prosthesis fits around the waist, sitting snugly over the hip bones to provide stability and to stop the socket slipping down. It is generally constructed from fibreglass or carbon fibre. Sometimes a flexible polypropylene liner is fitted inside the more rigid fibreglass socket. The socket is designed in such a way to allow the user to stand and walk as comfortably as possible while still being able to sit down easily.
There are a range of different prosthetic hip joints, knee joints and feet available to suit every need. Some hips and knees are free to swing and require a certain amount of muscle strength to ensure they do not buckle; others feature a hand-operated lock to give a very stable gait. Prosthetic feet can be made from wood, robber and carbon fibre, and are designed to give a stable base of support and a natural walking pattern. Your prosthetist will work with you to choose the best components to suit your needs.