Hip Preservation Surgery
The hip joint is one of the body's largest weight-bearing joints and is the point where the thigh bone (femur) and the pelvis (acetabulum) join. It is a ball and socket joint in which the head of the femur is the ball and the pelvic acetabulum forms the socket. The joint surface is covered by a smooth articular cartilage that cushions and enables smooth movements of the joint. Hip pain has become a common problem particularly in sportspersons involved in vigorous activities. The main reason behind the development of hip pain is due to changes in the shape or structure of the ball and socket type of hip joint. The treatment options for the management of hip disorders such as excruciating hip pain and hip dysfunction, in young patients, have been limited. However, the newer minimally invasive techniques have been found to be beneficial in these patients and these also avoid the need of hip replacement. Some of the common hip preservation surgical procedures include peri-acetabular osteotomy, proximal femoral osteotomy, open hip debridement, hip arthroscopy and cartilage restoration procedures.
An osteotomy is a surgical procedure that involves cutting and reshaping of a bone. Pelvic osteotomy involves reshaping a shallow hip socket so that it accommodates the ball of the hip joint (femoral head). Pelvic osteotomy is indicated in various hip disorders such as developmental dysplasia of the hip involving acetabular dysplasia, subluxation and dislocation, avascular necrosis of the capital femoral epiphysis (Legg-Calve-Perthes-Disease), and neuromuscular hip instability.
The articular surfaces of the hip joint are lined by a cartilage, known as articular cartilage. It has a smooth surface which allows the articular surfaces to slide over one another with minimal friction. Articular cartilage is often damaged by injury or normal wear and tear. Articular cartilage, when damaged or worn away, the affected joint becomes painful, stiff, and has limited range of motion. As the articular cartilage has limited ability to heal by itself, surgical repair may be required to stimulate the growth of new cartilage. Articular cartilage restoration relieves pain, improves function and can delay or prevent the onset of arthritis in the joint. Cartilage restoration can be achieved using different techniques.
- Microfracture surgery: Microfracture surgery is appropriate for patients having single lesion and healthy subchondral bone. Microfracture can be done using an arthroscope- a long, thin device with a tiny camera attached at the end to see inside your knee. Your surgeon uses a small pointed tool called an awl to make very small holes, microfractures, in the bone underlying the cartilage called subchondral bone. This stimulates the healing process by increasing the blood flow to the surface which brings in new cells that build new cartilage.
- Drilling: This technique involves use of a surgical drill or a fine wire to make multiple small holes through the damaged area to penetrate the subchondral bone. This generates a healing response within the defect. As the heat produced during drilling can cause injury to some of the tissues, it is considered less accurate than microfracture.
- Abrasion arthroplasty: Abrasion arthroplasty can be done using an arthroscope. This technique is similar to drilling, rather than drills or wires, high speed burrs are used to remove the damaged cartilage and to penetrate the subchondral bone.
- Autologous chondrocyte implantation: Autologous chondrocyte implantation (ACI) is a two-step procedure. The first step is an arthroscopic surgery to remove the tissue containing healthy cartilage cells from an area of the bone that does not carry weight. These cells are cultured and multiplied in a laboratory over a 3- to 5- week period. In the second step, the newly grown cells are implanted through an open surgical procedure, or arthrotomy. During this surgery, a periosteum, a layer of bone-lining tissue is sewn over the area of damaged cartilage. Once the area is sealed with fibrin glue, the cultured cartilage cells are injected underneath the periosteal cover.
This procedure is appropriate for patients with a single lesion of large area. As the patient’s own cells are used, chances of rejection are not a concern. However, it is a two-step procedure, requiring large incision and lengthy recovery.
- Osteochondral autograft transplantation: In this procedure, healthy cartilage (graft) taken from a non weight-bearing area is transferred to a damaged area of the knee. The graft is taken as a cylindrical plug of cartilage and underlying bone. Then the graft is matched with the damaged area and transplanted into place. This leaves a smooth cartilage surface in the joint. Transplantation may be performed using a single plug or by mosaicplasty where multiple plugs are used.
This technique is used for patients with small areas of cartilage damage because of the limited availability of the healthy cartilage from the same joint.
- Osteochondral allograft transplantation: During this technique, tissue graft taken from a cadaver donor, known as allograft, is used to repair the damaged cartilage. Allograft may be used if the cartilage defect is too large for an autograft.
Rehabilitation Your surgeon may recommend physical therapy following any of the hip preservation surgeries to strengthen the joint and the muscles and help restore mobility to the hip joint.