Osteonecrosis is a condition due arising from a diminution of blood supply to bone. It affects most importantly the upper end of the femur. If left untreated it progresses to bony collapse and arthritis. The causes are many like alcohol abuse, steroid intake, Caisson's disease, Gaucher's disease.
The patient can experience sudden pain in the hips which radiates to the knee and can be confused for knee pain. Gait is painful. In early cases, x- rays are negative and MR scans are diagnostic. Treatment in the early stages is controversial and there are no clear guidelines.
Prolonged bed rest and crutch walking have not been shown to relieve pain or halt progression of the disease.
Treatment in late cases
Core decompression does ameliorate symptoms. It is minimally invasive and does not involve a replacement. If it fails then a replacement is possible at a later date.
Treatment in late cases with advanced destruction
Treatment is by a total hip replacement if bony destruction is extensive. A partial or total surface hip replacement is done if destruction is confined to the surface cartilage alone. Since it occurs in young individuals, a Surface Hip replacement is a better option as it conserves bony stock and a total hip replacement can still be done at a later date. Resurfacing of the hip is restricted to those cases of osteo necrosis where the amount of destruction is less than 30 percent of the head.
Where it exceeds thirty percent, a new type of hip prosthesis called the Proxima hip is available in Chennai.
This Proxima hip is an uncemented metal on metal large diameter bearing. It has been performed for avascular necrosis and other conditions like ankylosing spondylitis, post traumatic arthritis following acetabular fracture.
Vascularised fiblar graft is done with the help of a microvascular surgeon.