Core Decompression Surgery for Avascular Necrosis of the Hip: What to Expect

If you’ve learned you have avascular necrosis (AVN) in your hip, and your doctor has mentioned core decompression surgery, you probably have questions. What does the surgery involve? Will it help? And how long until you feel like yourself again?

Core decompression is a minimally invasive surgery designed to save your own hip joint. When AVN is caught early, before the bone has started to collapse, the procedure can relieve pain, help the bone heal, and delay or even avoid the need for a hip replacement. Most people are walking soon after surgery and no longer need pain medication within about a week.

Avascular necrosis, also called osteonecrosis or bone death, happens when part of a bone loses its blood supply. Without blood flow, that area of bone begins to die.

In the hip, AVN most often affects the femoral head, the ball-shaped top of the thighbone that fits into the hip socket. Over time, the weakened bone can collapse, which leads to pain and arthritis. That’s why treating AVN early matters.

Common risk factors include long-term use of steroid medications, heavy alcohol use, and hip injury, though sometimes no cause is found. Early AVN may cause few symptoms. As it progresses, many people notice a deep ache in the groin or hip, especially when walking.

Core decompression relieves pressure inside the femoral head and gives the bone what it needs to heal. During the procedure, the surgeon creates a small channel into the damaged area of bone. This channel lets the surgeon remove dead bone, encourage new blood flow, and fill the space with material that supports healing.

Daniel Wiznia, MD, an associate professor of orthopaedics and rehabilitation and co-director of the Yale Avascular Necrosis and Osteonecrosis Program, developed a 3D-navigated technique for core decompression with his engineering research lab. It uses computed tomography (CT) scans to guide the surgeon to the damaged bone. Traditional core decompression relies on fluoroscopy, a real-time, two-dimensional X-ray. The 3D approach is designed to reach the damaged bone more precisely.

Below, Dr. Wiznia answers common questions about the procedure, how successful it is, and what recovery involves.

No. Core decompression is considered a minimally invasive, joint-preserving surgery. It’s a much smaller operation than a total hip replacement, which removes and replaces the joint.

The procedure creates a channel into the femoral head to:

• Reduce pressure inside the bone
• Remove or break up dead bone
• Stimulate blood flow to the area
• Deliver graft material that supports healing

To fill the channel and help the bone rebuild, surgeons may use bone marrow aspirate concentrate, which is a concentrated sample of your own bone-healing cells drawn from your bone marrow. Other options include demineralized bone matrix (donor bone processed to encourage new bone growth) and calcium phosphate materials, which act as a scaffold for new bone.

Although it’s less invasive than hip replacement, core decompression is still surgery, and it carries some risks, including fracture of the thighbone, missing part of the damaged area, ongoing pain, and collapse of the femoral head, even after treatment

Careful planning helps lower these risks. At Yale, we plan each surgery using imaging of your own hip, a 3D model, and a customized map of the damaged bone. A team of specialists also reviews each case.

With our CT-based, 3D-navigated technique, the surgery takes about one hour. That includes setting up the imaging, targeting the damaged bone, performing the decompression, and delivering the graft material.

Timing can vary depending on the technique, whether a graft is used, and whether one or both hips are being treated.

But the length of surgery matters less than getting the details right. That means reaching the damaged bone accurately, using the right amount of graft material, and choosing the approach that best fits your hip.

Core decompression works best when AVN is found before the femoral head has collapsed. Your surgical team will also consider:

• The size and location of the damaged area
• Whether the joint has started to collapse
• Your overall health and risk factors for AVN
• Your bone quality

If your hip isn’t a good fit for core decompression, your team will talk with you about other options.

For many patients, yes, especially when AVN is caught early and the damaged bone is targeted accurately.

In our research at Yale, more than 75% of patients showed no worsening of AVN in the treated hip at short-term follow-up. When we combined core decompression with hyperbaric oxygen therapy, we found that 88% of hips were preserved. Hyperbaric oxygen therapy involves breathing concentrated oxygen in a pressurized chamber to help support bone healing. Results were stronger in hips treated before collapse than after.

In a review of a national surgical database, Yale researchers also found that only a minority of patients who had core decompression needed a total hip replacement within five years. Most of those who did needed it within the first year.

To give each patient the best possible chance of success, we combine several approaches. These include advanced imaging, 3D surgical planning, careful choice of instruments, healing-support materials, hyperbaric oxygen when appropriate, and treatment of underlying health factors.

Healing happens gradually. Your skin incision usually heals within a few weeks. The bone inside the femoral head takes longer, because it needs time to rebuild its blood supply and absorb the graft.

Most patients can expect:

• Right after surgery: Walking and putting full weight on the leg, as your surgeon advises
• Within the first week: Stopping pain medication
• Over weeks to months: Steady improvement in pain
• After about three months: Returning to high-impact activities, like running or jogging, if your surgeon approves
• Over the following months: Follow-up imaging to make sure the bone is healing and there’s no fracture, graft problem, or collapse

Everyone heals at their own pace. Recovery depends on the size of the damaged area, how much bone was removed, the type of graft used, and any health conditions that affect healing.

Some soreness after surgery is normal and should ease over time. Contact your surgical team if you notice fever, or redness, warmth, or drainage at the incision; sudden, worsening hip pain, or trouble putting weight on your leg, or swelling, pain, or tenderness in your calf.

Call 911 if you have chest pain or sudden shortness of breath, which can be signs of a blood clot.

Often, yes, but it takes careful evaluation. Osteoporosis, a condition that makes bones thinner and weaker, can make the femoral head and the neck of the thighbone more likely to fracture during or after surgery. Your surgical team will look closely at your bone quality, the stage of your AVN, and your fracture risk to decide whether the procedure is right for you.

Many of our patients who travel for surgery fly home two to three days afterward. They are typically given a blood thinner to lower the risk of blood clots during travel.

The right timing for you depends on how well you’re moving, your pain control, your risk of blood clots, and your surgeon’s instructions. Check with your surgical team before you book a flight.

Most people return to light daily activities within the first week or two. Over the next few months, your care team will check your progress with follow-up imaging, and you’ll ease back into more demanding activities. High-impact exercise generally waits until about three months.

For many patients, core decompression preserves the hip joint for years. If it doesn’t, or if AVN is diagnosed after the femoral head has already collapsed, total hip replacement is a reliable option for relieving pain and restoring movement.

If you’ve been diagnosed with AVN, the best next step is to talk with an orthopedic surgeon who specializes in joint preservation. They can explain which options make sense for your hip.