"I was just diagnosed with avascular necrosis with medial joint collapse. Does this mean I will need a knee replacement? Does the dead bone keep extending? What can I do about the pain. Will I damage it if I continue to walk on it?"
First, what is avascular necrosis? It is also known as osteonecrosis, aseptic necrosis, and osteochondritis dissecans. Avascular necrosis is a pathological process that has been associated with numerous conditions and therapeutic interventions. What happens is there is compromise of the bone vasculature leading to the death of bone and marrow cells. Avascular necrosis of the knee is the third most commonly involved joint after the hip and shoulder.
Avascular necrosis of the knee develops in adults secondary to underlying disease or predisposing factors such as steroid use, alcoholism, connective tissue disorders (lupus), hemoglobinopathies, and HIV. Avascular necrosis is usually asymptomatic in the knee, unless epiphyseal collapse occurs.
The treatment of avascular necrosis is a controversial subject in the orthopedic literature. The goal of therapy is to preserve the native joint for as long as possible.
Here are the options for your knee:
• Conservative therapy: Conservative or nonoperative management for avascular necrosis of the hip or knee includes bed rest, partial weight bearing with crutches, and weight bearing as tolerated, in addition to nonsteroidal agents (ibuprofen or motrin) or other pain meds. This approach has generally been ineffective at halting the progression of disease….in other words additional intervention is usually needed.
• Bisphosphonates: These have been best studied with avascular necrosis of the hip showing that you can lower resorption of necrotic bone with bisphosphonates (fosamax, boniva, etc) and decrease some of the pain.
• Joint replacement: Total knee replacement is an option in patients who have avascular necrosis of the knee. The success rate may be lower in patients with osteonecrosis than in those receiving joint replacement for other reasons.
• Other treatments that have not met with great success in the trials to date include the use of electrical stimulation by direct current, pulsed electromagnetic fields, and pharmacologic agents such as ergoloids, naftidrofuryl and vincamine aimed at reducing bone marrow pressure.
- Dr O.