Osseointegration is defined as the formation of a direct interface between an implant and bone, without intervening soft tissue. The term refers to the direct structural and functional connection between living bone and the surface of a load-bearing artificial implant. The surgical procedure first started in Sweden in 1990. But US doctors have began to practice percutaneous osseointegrated prostheses (POP implant) only in 2015. The first surgeries for the two veterans took place on Dec. 7 and Feb. 8, 2015, when was involved implanting the device into the femur bone and attaching a post to the femur component of the device through the skin. During this year, doctors at the Salt Lake VA plan to attach osseointegrated prosthetics for eight amputee veterans.
Disadvantages of standard prostheses with a socket attachment system
Anyone with a traditional prosthesis can be a candidate for osseointegration, as it is proposed for knee or elbow amputees (above and below). Traditionally, amputees use standard prostheses with a socket attachment system. But a socket prosthesis associates generally with big difficulty and pain. It’s typically due to one of the following:
- the socket causes discomfort and restricts range of motion;
- amputees with heterotopic ossification (results from trauma where a piece of new bone grows near the periosteum of the femur) also experience severe pain while weight bearing in the socket, because the bone tissue compresses muscle and skin against the hard socket causing pain;
- weight bearing in a socket causes several issues due to heat and skin wearing. Heat causes the residual limb to change in size and sweating of the residual limb which can lead to skin breakdown, infection and pain.
Advantages of osseointegrated prostheses over a prosthetic socket
Osseointegration (OI) uses pure titanium socket device that is implanted directly into the residual bone. There are several advantages associated with osseointegration:
- is increased diapason of motion due to a lack of impediment from a socket;
- there is a lack of skin or residual limb problems from perspiration, sores, and discomfort;
- no pressure sores or skin irritation;
- donning/doffing utilizes a wrench and can be done fast and easy in seconds;
- because it is affixed via a wrench, the same fit and orientation is guaranteed every time;
- a phenomenon known as “osseoperception” has been noted with these implants;
- no more fit issues due to weight gain/loss;
- increased acceptance of prosthesis, increased proprioception, and reduction of pain and discomfort.
Because the osseointegrated prostheses is directly implanted into the bone, then the femur feels the vibrations of the prosthesis during walking. This allows the amputee to differentiate different surfaces much like how a healthy leg does. Due to the central sensory feedback, percutaneous osseointegrated prostheses can increase proprioception and also help with phantom sensation. The osseointegration prosthesis increases quality of amputee’s life. The transfemoral amputee is able to wear his prosthesis longer due to decrease in pain and skin breakdown.