Hyperbaric Oxygen Therapy for Avascular Necrosis (Osteonecrosis)
HBOT for avascular necrosis is investigational, not FDA-approved. A small 2010 RCT studied early-stage hip osteonecrosis. Here is what the evidence shows.
Important: In the United States, hyperbaric oxygen therapy is not FDA-approved for avascular necrosis. This is an investigational, off-label use. Evidence is preliminary and comes mostly from small studies. Insurance will not cover HBOT for this condition. All costs are out-of-pocket.
Avascular necrosis kills bone tissue when its blood supply is cut off. In the hip, that means the femoral head, the ball at the top of the thigh bone, slowly loses the living cells that keep it strong. Caught early, before the bone collapses, the question many patients ask is whether anything short of a hip replacement can change the course. Hyperbaric oxygen is one of the options that comes up in that search, and the honest answer involves one small randomized trial and a lot of unsettled questions.
What Avascular Necrosis Is
Avascular necrosis (AVN) goes by several names. You may also see it written as osteonecrosis or aseptic necrosis. All three describe the same process: an interruption in blood flow starves a section of bone of oxygen until the tissue dies.
The femoral head is the most common site, though AVN also affects the knee, shoulder, and ankle. Known risk factors include long-term or high-dose corticosteroid use, heavy alcohol intake, hip trauma such as fracture or dislocation, sickle cell disease, and decompression sickness in divers. In many cases no single cause is identified.
Doctors stage AVN with imaging, usually MRI in the early phase. The Ficat and Arlet classification is one common system. Stages I and II are pre-collapse, meaning the bone is dying but the round shape of the femoral head is still intact. Stage III and beyond involve collapse of that surface, after which arthritis and mechanical pain tend to follow. The stage matters a great deal here, because the treatments that aim to preserve the joint, including HBOT, are studied in the pre-collapse window.
How This Differs From the Approved Bone Conditions
It is easy to confuse AVN with two bone conditions that HBOT genuinely is FDA-approved to treat, so the distinction is worth drawing clearly.
Osteomyelitis is a bone infection. HBOT is a cleared adjunct for the refractory form because raising oxygen tension helps the immune system and antibiotics clear bacteria. AVN is not an infection. Nothing is being killed off by the immune system, the bone is dying from lack of blood.
Osteoradionecrosis is bone death caused by prior radiation therapy, most often in the jaw. It falls under the FDA-cleared delayed radiation injury indication. AVN has nothing to do with radiation. Because the names rhyme and both involve dead bone, clinics sometimes blur the line. They are separate diagnoses with separate evidence and separate coverage rules.
Why HBOT Is Being Studied
The rationale is straightforward on paper. AVN is a problem of oxygen-starved bone, and HBOT raises the amount of oxygen dissolved in plasma well above what breathing room air delivers. The mechanism behind HBOT is that elevated pressure forces more oxygen into the bloodstream, where it can reach tissue that a compromised blood supply struggles to feed.
Proposed effects in early AVN include reducing the swelling and raised pressure inside the bone marrow, supporting the survival of bone cells in the threatened zone, and stimulating angiogenesis, the growth of new blood vessels. These are biological hypotheses drawn from how HBOT behaves in other tissues. They are not confirmed mechanisms in human hip disease, and a plausible rationale is not the same thing as a proven result.
What the Research Shows
The most cited human trial is Camporesi et al. (2010), published in the Journal of Arthroplasty. It was a double-blind, randomized, controlled study of 20 patients, all with unilateral femoral head necrosis at Ficat stage II. Patients received 30 sessions over six weeks of either hyperbaric oxygen or compressed air, with a blinded physician measuring pain and range of motion. The oxygen group showed significant pain improvement after 20 treatments and range-of-motion gains between treatments 20 and 30 compared with the air control. At long-term follow-up the authors reported that the treated patients had not required hip replacement, with radiographic healing seen in most of the treated hips (PMID: 20637561).
That is an encouraging signal, and it is also a single study of 20 people from one center. Twenty patients is small. A result that holds up in a trial that size still needs replication in larger, multicenter trials before it can be called established, and that replication has not happened. A 2017 review in Undersea and Hyperbaric Medicine, from the same research group, framed femoral head necrosis as a treatable target while acknowledging that the etiology is unclear and that no single agreed protocol exists (PMID: 29281187). Read together, the evidence is best described as promising and thin, not settled.
There is also a recognition wrinkle that drives confusion. In 2024 the Undersea and Hyperbaric Medical Society (UHMS) added avascular necrosis (aseptic osteonecrosis) as an approved indication in the 15th edition of its Hyperbaric Medicine Indications Manual, and some European hyperbaric bodies have listed femoral head necrosis for years. A professional society indication is not the same as FDA clearance or insurance coverage, however. HBOT for avascular necrosis is not in Medicare’s National Coverage Determination (NCD 20.29), and Medicare and commercial insurers generally do not cover it. A clinic citing UHMS or European practice is not describing guaranteed US coverage.
Where It Fits Against Standard Care
Standard management of AVN depends heavily on stage. In early, pre-collapse disease, options that aim to save the joint include protected weight-bearing and core decompression, a procedure that drills into the femoral head to relieve pressure and encourage new blood vessel growth, sometimes combined with bone grafting. Once the femoral head has collapsed, total hip arthroplasty, a hip replacement, becomes the reliable way to restore function and relieve pain.
HBOT, where it is used at all for AVN, is positioned as an early-stage, joint-preserving attempt, not a replacement for surgery and not a rescue once the joint has failed. No one should read the Camporesi result as a promise of avoiding surgery. It is one small trial in a narrowly defined group of patients. An orthopedic surgeon and, where relevant, a hyperbaric physician are the people who can stage your disease and weigh whether any joint-preserving approach is reasonable in your case.
Cost and Coverage
Because this is off-label, you pay out-of-pocket. HBOT sessions commonly run $250-450 each, and the protocols studied for AVN involve 20 to 30 or more sessions, which puts a full course in the several-thousand-dollar range. Rates change annually, so verify current pricing with your facility’s billing team. Do not expect insurance to reimburse HBOT for avascular necrosis. If a clinic implies it will, ask them to put the coverage claim in writing and confirm it directly with your insurer first.
FAQ
Is HBOT FDA-approved for avascular necrosis? No. In the US it is investigational and off-label. Insurance will not cover it for this condition.
What did the Camporesi 2010 trial find? In 20 patients with Ficat stage II hip necrosis, the hyperbaric oxygen group improved on pain and range of motion versus a compressed-air control. PMID: 20637561. It is a single small study.
Does HBOT help once the hip has collapsed? The research is in pre-collapse disease (Ficat I-II). After collapse, HBOT is not expected to rebuild the joint surface.
Is avascular necrosis the same as osteomyelitis? No. Osteomyelitis is a bone infection that HBOT is approved to treat as an adjunct. AVN is bone death from interrupted blood supply, not infection.
How much does it cost? Roughly $250-450 per session across 20 to 30 or more sessions, all out-of-pocket. Rates change annually, verify with your facility.
References
- Camporesi, E.M. et al. (2010). Hyperbaric oxygen therapy in femoral head necrosis. Journal of Arthroplasty. PMID: 20637561
- Camporesi, E.M. et al. (2017). Review on hyperbaric oxygen treatment in femoral head necrosis. Undersea and Hyperbaric Medicine. PMID: 29281187
Related Pages
Medical Disclaimer: This page is for informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Hyperbaric oxygen therapy for avascular necrosis is investigational and not FDA-approved. Always consult a qualified healthcare provider before pursuing any medical treatment. Individual outcomes vary. This site does not establish a doctor-patient relationship.