OSSEOINTEGRATION
Osseointegration describes the science of implanting man-made, load bearing devices directly into the bone, whereby the fixture bonds with the surrounding tissue. The process was originally pioneered as early as the 1950s in dental treatments, when titanium dental implants were first integrated into the human jaw. Today, osseointegration is also a feature of leg, arm and facial prosthetics, in addition to hearing aid connections.
Powerful collaborative efforts between healthcare providers, the research community and the medical industry have lead to a number of advances in the field. The most recent definitions state that an implant is regarded as ‘osseointegrated’ when there is no progressive relative movement between the bone and the implant. Essentially this means an anchorage mechanism, which can withstand all normal conditions of loading, is incorporated into the living bone.
More than 100 amputees have been treated with osseointegration techniques to date, most with excellent results. Bone-anchored prostheses eliminate many of the problems that might arise with a prosthetic socket. For those with a very short transfemoral residual limb, or after revision surgery to transfemoral level, this technique is a good alternative.
The surgical procedure is performed in two stages. In the first stage, a specially designed titanium screw known as a fixture is inserted into the marrow space of the residual limb. In the second stage, six months later, a titanium extension known as an abutment is attached to the bottom of the fixture and brought out through a hole in the skin. The prosthesis is then attached to this abutment.
As with all surgical treatments, there is a risk of complications which can alter the treatment or compromise the results, but the user will ideally regain their so-called ‘osseoperception’, which greatly enhances the control he or she has over the prosthetic device they are using. An increasingly frequent form of treatment, osseointegration requires the use of a highly developed prosthesis for the full benefit of the method to be realized. This promising treatment for amputees has been widely developed in Sahlgrenska Universitetssjukhuset, Sweden, and recently started to be implemented in other countries.