Hip Disarticulation (HD) and Trans-Pelvic (TP)
A hip disarticulation (HD) or trans-pelvic (TP) prosthesis typically consists of a custom-made, flexible inner socket with a rigid outer frame, a hip joint, rotator, knee unit, pylon, and foot. HD and TP sockets cover the amputated side and also wrap around the person’s sound buttock and torso, with secure straps fastening the two sides together.
Your Hanger practitioner may utilize a CAD or computer aided design approach to create the precise shape and contour of your residual limb. By taking measurements of the patients residual limb, Hanger’s Insignia system creates a series of three-dimensional images that are sent to an automated carver, creating a precision form that is used to fabricate a temporary or test socket. Plaster casting is another, more hands-on process that is sometimes used to create a custom mold for the socket. Your prosthetist will decide the most effective means for casting your socket.
High-level amputations such as HD or TP can be challenging to fit. For the patient, the compound loss of the foot, ankle, knee and hip make it more difficult to achieve comfort and stability. Also, consider the fact that walking with a HD or TP prosthesis can require up to two times the energy of normal ambulation. Some HD and TP amputees are discouraged from considering the use of a prosthesis by well-meaning healthcare professionals and family members. Others may have attempted to use a prosthesis and in frustration, decided they could be more mobile using crutches or a wheelchair. If you see yourself in any of these difficult situations, take heart: The Hanger Lower Extremity Prosthetics Program has a good rate of success fitting high-level amputations. We have many HD and TP patients who walk with a prosthesis everyday and participate in most life activities including going to school, driving, working, dating or marrying, and having children.
Years of research and experience have led us to develop an anatomically correct socket for HD and TP users. The skillful casting of the residual hip or pelvic area is the first critically important step. The goal is to shape the socket as a replica of the sound side of your body. Use of a test/temporary socket allows you and your prosthetist to carefully refine the fit and make repeated modifications for comfort. Often the test socket is combined with the rest of the components so you can try standing and walking. When adjustments are completed, a final definitive socket is cast. The mechanical hip joint is out-set in its own compartment next to the actual socket cavity, placing it in the same space the natural hip joint once occupied. The socket has a solid floor that is parallel to the ground. This holds the residual soft tissues inside the socket and helps to eliminate painful pressure points where the socket presses on the bone.
The challenges of learning to use a HD or TP prosthesis call for an extra measure of perseverance from the patient, the prosthetist and the physical therapist. It usually takes several months of physical therapy and daily use for the user to feel independent and confident.