As regular readers will know I recently had the opportunity to attend Dorset Orthopaedics catastrophic injury conference in Farnborough. One of the interesting things to come out of the conference was the growing work, which is now being done in the UK in terms of OI.
First – what is OI?
Osseointegration [in terms of prosthetics at least] was discovered in the 1950s by professor Per -Ingvar Branemark and is based on the ability of human bone cells to attach to a metal surface. It is used for the permanent anchorage of artificial limbs to the human skeleton: a metal (titanium) implant is inserted into the bone of the arm or leg and this implant penetrates through the skin. The artificial limb (prosthesis) is then attached to this implant with a connector.
The attachment of the osseointegrated prosthesis is said to be much more stable therefore allowing for improved walking and joint movement.
An osseointegrated prosthesis does not cause skin breakdown and socket fit issues are removed. Because the prosthesis is directly attached into the bone, patients are said to feel as if their prosthesis as part of their own body by natural osseoperception.
Two osseointegration systems:
- Screw shape prosthesis (OPRA): This prosthesis was developed by the osseointegration pioneers in Sweden and is the system with the longest and largest follow up. The titanium prosthesis is derived from dental implants, has a screw design and a relatively short length. The titanium screw, however, requires a relatively long time for solid osseointegration and, therefore, the rehabilitation period until full weight bearing is long- typically 6 to 12 months. Another disadvantage is that the implant may become loose and the distal abutment is relatively weak. The abutment may bend or break at higher bending forces during daily activities.
- Press fit prosthesis (ILP): The design and implantation technique was derived from orthopedic hip prostheses. This prosthesis was developed in Germany and is a chrome cobalt molybdeen alloy rod with a 3D tripod surface structure. It is the system being used by the Australian team who, according to Dorset Orthopaedic, report the lowest infection rates. The prosthesis can be load bearing much earlier than the OPRA system. The osseointegration period is 6 weeks. The osseointegration is therefore quick and the rehabilitation period short.
Traditionally there hasn’t been much – if any – OI market in the UK. There are risks of infection, bone fractures and I am given to understand that it isn’t generally suitable for anyone doing high impact activities such as running.
I have dealt with one litigated claim in the past where the claimant travelled to Sweden for his regular treatment but the whole situation was made more complicated by the lack of specialist knowledge and clinical care available in the UK.
So why are we talking about OI now? There are less than 1,000 patients worldwide and the teams performing this type of surgery have traditionally been based outside the UK: Sweden, Australia, Netherlands…
I am, however, aware from my membership of the American College of Rehabilitation Medicine that the VA are looking more and more at the use of OI and therefore it was interesting to hear Dorset Orthopaedic announce that they are now managing 14 patients in the UK and that Norbert Kang based at the Royal Free has now undertaken 4 or 5 OI operations using the ILP implant.
It very much looks as if OI as a technique is slowly but surely coming to the UK. Where one leads the others follow… for all the insurers out there I expect that we will start to see a slow but steadily increasing stream of cases dealing with this old but innovative technique.