What is osseointegration?
The process of osseointegration, otherwise known as direct skeletal fixation, involves a permanent titanium implant being surgically inserted into the residual limb with an end piece that protrudes out of the skin to which a prosthesis can be attached.
The idea of using osseointegration was first pioneered in dentistry by Professor Per-Ingvar Branemark. His son, Professor Rickard Branemark, developed the system further and in May 1990 performed the first transfemoral screw-fixated titanium implant.
What systems are available?
Currently there are two main osseointegration techniques available in the UK: OPRA and OGAP-OPL.
OPRA is a Swedish system where the end piece is attached during a second operation, approximately six months after the initial surgery, to insert the implant which is covered and left to fuse with the bone. The rehabilitation process takes about six to 12 months with no weight-bearing for two weeks after the second surgery. Advocates of the two stage system say that it reduces the infection rate and allows the bone to fuse more fully before weight-bearing begins, making it a safer procedure.
OGAP-OPL is an Australian system developed by Professor Munjed al Muderis which does not require a second surgical procedure. Patients can begin immediate partial weight-bearing with full weight-bearing after 4-6 weeks which advocates of this system say is its major advantage.
Superficial infection is common but is usually adequately treated with antibiotics. Deep infection is rare but commonly requires implant removal although re-implantation is usually possible. In the early stages the OPRA system reported high rates of deep infection but this has been reduced significantly in recent years.
Implant structure failure is rare but possible. Bone fractures around the implant are also possible but are rarer still. It is also possible that the implant will fail to osseointegrate (integrate with the patient’s bone) at all.
Contraindicators (i.e. reasons that may prevent surgery) include:
- Diabetes or vascular disease
- Chemotherapy or immunosuppression
- Skeletal immaturity
- Poor bone quality (radiotherapy, osteoporosis, metabolic bone disease or renal insufficiency)
- Severe cognitive or psychiatric disorders
Potential contraindicators to surgery can include:
- Weight over 100kg
- Less than 20 or over 70 years of age
- Skin disease affecting amputation
- Femur less than 8cm in length
Osseointegration could significantly reduce pain levels, both neuropathic and phantom. It is reported to improve control, stability and walking ability. It should also lead to increased mobility, improved gait, reduced discomfort while sitting, an increase in the use of prosthetics, improved hip range of movement and better vibrotactile sensation. Osseointegration users can use all the same prostheses as traditional socket users but at a cost of up to 30% less because they do not require a socket.
Cycling and swimming should be possible if the risk of infection is managed but running is not currently recommended due to the forces involved.
Overall it is reported to lead to a substantial improvement in amputees’ quality of life, whether they are single or bilateral amputees.
The most recent results of the OPRA study found that:
- By two years post-surgery, 50% of patients reported using a prosthesis at home all the time. This increased to 71% after five years compared to 0% pre-surgery.
- By five years post-surgery, 93% of patients reported using a prosthesis outdoors all the time, compared to just 18% pre-surgery.
- At two years post-surgery, no patients reported not using their prosthesis due to pain. This did increase to 14% at the five year follow up but is still a significant improvement when compared to the 91% of patients who reported not using a prosthesis due to pain pre-surgery.
Until recently, osseointegration was not available for civilians in the UK forcing anyone who wanted to undergo the surgery to travel abroad. The surgery is now available privately at a number of clinics in London at a cost of around £40,000 to £50,000 for lower limb surgery making it a much more economically viable option in cases where amputees cannot use a socket prosthesis or choose to go down this route.
It has the potential to drastically reduce the value of a claim with the removal of the need for sockets and less post-operative care needs, improved the chance of returning to work and potentially negating the need for alternative accommodation.
Despite being available for a number of years it is still a relatively new procedure and the long term potential is still unknown. If a claimant wishes to undergo osseointegration surgery they will have to accept that these other areas of their claim will, in all likelihood, be reduced as a result.
Osseointegration has the potential to put a claimant much closer to the position they were in prior to amputation when compared to a socket fitting prosthesis. While each case will be specific on its facts and the parties will have to be led by expert evidence, we will only really know the true impact osseointegration can have on claims when insurers are willing to fund the surgery in appropriate cases.