Age
For whom is this hip prosthesis particularly suitable? Due to the special prosthesis design of a short shaft prosthesis, it can be implanted in a bone-saving way. The bone in the shaft of the thigh bone (femur) remains unchanged with this operation. Young people in particular, who have to be implanted with an artificial hip joint, must expect a change of operation. Therefore the short shaft prosthesis, like the one in the McMinn prosthesis (cap prosthesis), is suitable for young people.
Aftercare
The follow-up treatment of a short shaft prosthesis is usually comparable to that of a cementless prosthesis. Normally a partial load of two to four weeks must be overcome after implantation. During this time a part of the load must be absorbed by walking with walking sticks.
Contraindication
Since the short shaft prosthesis (Mayo prosthesis) only anchors itself via a very short shaft, optimum bone quality is a mandatory requirement for implantation of this prosthesis model. Contraindications against implantation are therefore
- Osteoporosis (bone decalcification)
- Atypically shaped femoral neck (varic or valgus femoral neck = femoral neck with too much or too little flexion)
Advantages and disadvantages short shaft prosthesis
The main advantage of a short shaft prosthesis is that the shorter shaft of the implant means that less of the femoral neck bone has to be hollowed out in order to insert the prosthesis afterwards. As a result, a larger portion of the femoral bone remains intact and preserved, thus functionally and anatomically corresponding to the original, healthy femoral neck bone. These are optimal conditions in case another operation is necessary to change the prosthesis.As a result, the bone-saving short shaft prostheses are particularly suitable for younger patients in whom, due to age and normal prosthesis wear, a prosthesis change will be necessary and probable after about 20 years.
A disadvantage of the short shaft prostheses is the cementless implantation. The process of “ingrowth” can sometimes lead to problems and the time until the hip joint is fully loaded is usually longer than with cementation. In the stabilization phase of ingrowth, symptoms such as loading and/or bone pain may occasionally occur. In rare cases, ingrowth and thus bone stability may not occur at all, making renewed surgery and a change to another prosthesis model unavoidable.
