Osseointegrated prosthesis for amputees
Osseointegrated (OI) prosthesis are offered for both femoral and upper extremity amputees.
Femoral amputees usually wear a socket suspension prosthesis, but many patients face rather severe problems with the prosthesis e.g. fitting problems due to varying edema of the amputated leg, skin problems with blister or eczema, sitting discomfort a.o. Further some patients have such a short stump that it is not possible to provide the patient with a socket prosthesis. For these patients an OI-prosthesis can be a favourable alternative treatment option.
The OI treatment in Denmark is only offered at the department of orthopaedic surgery in Aarhus.
The operation is a two-stage procedure. At the first operation a treaded fixture is implanted into the bone and six months later (three months at upper extremity) an abutment is attached to the fixture at the one end and is protruding through the skin at the other end to be coupled to an external prosthesis. After the second operation the patients go through a rehabilitation period with gradually increased load on the prosthesis, a period which may last up to six months. The patients must fulfill certain criteria to get an OI-prosthesis. Due to the long rehabilitation period the patient must be able to cooperate and take an active part in the process indicating a high degree of compliance. Smokers can not be operated, and vascular insufficiency, BMI above 30 and immunosuppressive treatment are contraindications as well. Patients operated with an OI-prosthesis in the femur report increased walking ability, increased sitting comfort, osseoperception due to the direct transmission of pressure from the ground through the prosthesis to the bone and increased HRQL (life quality).
For finger amputations especially when the thumb has been amputated at metacarpo-phalangeal joint the pinch grip can be restored by an OI-prosthesis and the patients are able to perform a lot of daily activities that are not possible without the finger. At the forearm level an OI-prosthesis will give an increased freedom of movement as the elbow joint will not be fixed within a socket prosthesis and at the brachial level a residual bone length of the humerus of 9 cm is enough to provide the patient with a prosthesis. In general for upper extremity amputees, an OI-prosthesis provides the patient with a stable connection between the stump and the external prosthesis, which gives excellent possibility for supplying the patients with advanced prosthetic technology.
Several research projects are established, such as evaluation of changes in bone quality (DXA), fixation of the prosthesis (RSA), gait analysis and evaluation of general function before and after surgery.