What Is Avascular Necrosis?

Avascular necrosis occurs when bone loses its blood supply and begins to die. It most commonly affects the hip (specifically the femoral head) and is the second most common in the knee, though it can also occur in the shoulder, ankle, elbow, or wrist.

AVN can be caused by:

• Trauma or injury

• Certain medications, including long-term steroid use

• Underlying diseases that affect blood flow

Left untreated, AVN of the hip often causes pain while walking, limping, and groin pain, and can progress to the point where a joint collapses and requires replacement surgery.

What the Research Shows: Hip (Femoral Head) Necrosis

A 2010 double-blind, randomized, controlled study by Camporesi et al., published in The Journal of Arthroplasty, followed 20 patients with Ficat stage II femoral head necrosis. Each patient received 30 HBOT sessions over six weeks.

Key findings:

• Significant pain improvement appeared after 20 treatments, with continued gains in range of motion between 20 and 30 treatments

• All patients remained substantially pain-free at 7-year follow-up, and none required hip replacement

• MRI follow-up showed substantial bone healing in 7 of 9 hips evaluated

A broader literature review by Gunes et al. (2017), covering ten studies on HBOT for osteonecrosis, found that seven were methodologically strong enough to draw firm conclusions from. Across these studies, HBOT consistently helped with pain relief and reduced bone marrow edema (swelling within the bone), with the best long-term results in patients treated during the earlier stages of AVN. The reviewers recommended starting HBOT as early as possible after diagnosis.

What the Research Shows: Knee Necrosis (Osteonecrosis of the Knee)

A 2018 study by Bosco et al., published in Arthroplasty Today, followed 37 patients (ages 29–68) with osteonecrosis of the knee. Most patients (83.7%) had earlier-stage disease (Aglietti stage I–II), while 16.3% had more advanced stage III disease.

Key findings:

• After 30 HBOT sessions, 86% of patients improved on the Oxford Knee Score (a standard measure of knee pain and function); 11% worsened and 3% were unchanged

• After 50 sessions, all patients showed improvement

• Follow-up MRI showed the swelling around the knee bone had resolved in all but one patient

Is HBOT Right for You?

HBOT is a non-invasive option, and its side effects are minimal compared to the risks of joint replacement surgery. That said, the existing research — while promising — is still based on relatively small studies, and reviewers have consistently called for larger trials to confirm these results. HBOT should be discussed with your physician as part of a broader treatment plan, particularly if you're diagnosed in the earlier stages of AVN, when outcomes tend to be best.

Safety and Expert Care

At Bay Area Hyperbarics, treatment decisions are always made under expert medical guidance, with safety as the top priority. Hyperbaric oxygen chambers used for FDA-approved indications are well-studied and have a strong overall safety record.

Consult a healthcare provider before starting any new treatment. This article is for educational purposes and does not replace medical advice from your care team.

Frequently Asked Questions

Does insurance cover HBOT for avascular necrosis? Coverage varies by insurer and individual case. Our team can help verify your specific benefits before you begin treatment.

How many HBOT sessions are typically needed for AVN? Published studies used protocols ranging from 30 to 50+ sessions, depending on the joint affected and the severity of disease.

Can HBOT help me avoid joint replacement surgery? In the studies above, most patients avoided joint replacement, particularly those treated at earlier disease stages — but individual outcomes vary, and this decision should be made with your orthopedic physician.

If you or a loved one has been diagnosed with avascular necrosis or osteonecrosis, talk to our team about whether hyperbaric oxygen therapy may be right for you.

Call Us: 408-356-7438