The hip is a ball and socket joint that is weight bearing. The blood supply to the femoral head, the ball part of the joint, is precarious, somewhat like the brain. If this blood supply is disrupted for any reason, weight bearing begins to take its toll on the joint. Without a normal blood supply, natural repair of the normal wear and tear of the joint cannot take place and the femoral head collapses and flattens. The mismatched ball and socket grinds away at the joint and wears it out. Afflicted patients experience progressive pain and loss of mobility. The medical term for this condition is avascular necrosis of the hip or AVN.
Many different things can disrupt the blood supply to the hip and cause AVN. Direct traumatic injury, usually from an automobile accident, occurs commonly enough: A fracture of the femoral neck or a hip dislocation can lead to AVN within a few months or be delayed as long as two years. Treatment with steroids, usually at high doses for long periods, is another common cause of AVN. Alcoholism is a clear risk factor for AVN. But many cases of AVN, maybe most, are idiopathic, i.e., we don’t have the foggiest notion why the patient develops the problem.
The usual approach to treatment of severe AVN is a hip replacement, known in medical circles as a THA or total hip arthroplasty. Obviously, orthopedic surgeons will only put an artificial hip in if the diseased hip is in bad shape. So, a lot of patients are out there who are in early stages of AVN, have pain and difficulty walking, but are not bad enough to warrant a THA. Treatment options for these patients with early AVN is much the same as other arthritis sufferers.
But unlike most causes of arthritis, AVN is a disease of blood supply and it seems logical that hyperbaric oxygen might have a role to play. In 1989, Dr. Neubauer reported a patient with AVN who chose hyperbaric oxygen therapy rather than have a THA. The patient did remarkably well clinically and showed healing by MRI criteria. Nothing much happened after Dr. Neubauer’s case report. I recall getting a few referrals but I was unable to obtain insurance approval for them-I assume those patients eventually went on to THA.
More recently a medical group from Israel reported a series of 12 patients with an early stage of AVN who were treated with hyperbaric oxygen. Nine of the 12 treated with hyperbaric oxygen had complete healing by MRI criteria. Although the report is a little unclear, it seems like 2 of the 3 non-healers had AVN from steroids and the third non-healer became asymptomatic, i.e., 10 of the 12 patients treated with hyperbaric oxygen had complete relief of their symptoms and 9 of those had complete healing by radiologic criteria. Regardless, it is plain that most patients with early AVN should heal with hyperbaric oxygen therapy.
Based on the Israeli group’s experience, it seems like hyperbaric oxygen should be offered to patients, particularly young patients, with early AVN. No one wants to do a THA on a young patient and many AVN patients are young. I suspect that if young AVN patients were given the choice, most would choose a trial of hyperbaric oxygen over a THA or waiting enough years for their hips to be bad enough for a THA. Few have that choice, unfortunately. The typical patient is at the mercy of his insurer, which really means he is at the mercy of some anonymous guy wearing green eyeshades.