Patients who suffer from the pain and immobility caused by osteoarthritis and rheumatoid arthritis have an option of joint replacement surgery. Joint replacement surgery is quite common and enables many individuals to function properly when it would not be otherwise possible to do so. Artificial joints are usually comprised of metal, ceramic and/or plastic components that are fixed to existing bone.
Such joint replacement surgery is otherwise known as joint arthroplasty. Joint arthroplasty is a well-known surgical procedure by which a diseased and/or damaged joint is replaced with a prosthetic joint. In a typical total joint arthroplasty, the ends or distal portions of the bones adjacent to the joint are resected or a portion of the distal part of the bone is removed and the artificial joint is secured thereto.
One type of bone damaging disease is Avascular Necrosis (AVN). In AVN, the bone is damaged due to a loss of blood supply. Eventually, the bone tissue dies, causing the bone to collapse. In a hip joint, AVN can cause the collapse of the femoral head.
Most commonly, AVN is treated by an orthopedic surgeon who performs a total hip replacement (THR) procedure. In a THR procedure, the entire hip joint is replaced with a prosthetic implant. The implant includes an acetabular cup that fits in the acetabulum, a ball for mating with the acetabular cup, and a stem that extends into the femur. However, this is a very invasive and major surgery.
In China, at least one surgeon has used a spherical Nickel Titanium alloy, more commonly known as Nitinol cage. A canal is drilled through the femur and the Nitinol cage is inserted. The Nitinol cage is compressed during insertion and placed inside of the femoral head. Once inside the femoral head, the Nitinol cage then returns to its spherical shape and reinforces the femoral head. The canal is then packed full of bone graft or bone cement.
However, there are problems in manufacturing the cages. In China, the cages were hand made. Utilizing hand made cages is prohibitive to mass manufacture and use. Others have tried to consistently mass manufacture Nitinol cages using mechanical methods without any success, creating a Nitinol tube, and not a sphere as needed.
The present invention is directed to alleviate at least some of the problems with the prior art.