Saving a Hip Losing Its Blood Supply, Stage by Stage

What are the surgical options for avascular necrosis of the hip?

The options divide sharply around one event: collapse of the femoral head, the ball at the top of the thigh bone. Before it collapses, joint-preserving surgery such as core decompression, sometimes with bone grafting, aims to relieve pressure inside the bone and preserve the natural hip. Once the head has collapsed or the joint has become arthritic, total hip replacement becomes the dependable answer. Because avascular necrosis tends to progress rather than settle, evaluation is usually not something to defer indefinitely.

The single most important fact about the femoral head is whether it has collapsed yet. Almost every treatment decision follows from that.

Why avascular necrosis is not ordinary arthritis

Osteoarthritis is a degenerative, wear-and-tear disease in which joint cartilage gradually breaks down 1Ref 1National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) (2023).Osteoarthritis.That osteoarthritis is a degenerative, wear-and-tear joint disease driven by cartilage breakdown, the mechanism that distinguishes it from blood-supply-driven osteonecrosis.. Avascular necrosis, also called osteonecrosis, works differently: the blood supply to a segment of bone is interrupted, the bone tissue dies, and the weakened area can eventually cave in under load. The joint damage in avascular necrosis is a consequence of that structural failure, not of decades of gradual wear.

That distinction is why the familiar 'try conservative care for a long while' pattern does not map cleanly onto this condition. Osteonecrosis often affects younger adults and can advance over months. Understanding what drives it, and its early warning signs, is its own subject worth reading, from the avascular necrosis hip symptoms that first appear to the osteonecrosis risk factors steroids alcohol and injury that commonly underlie it.

Staging governs the choice

Treatment tracks the stage, and staging systems all pivot on the same milestones: whether the head has collapsed, and whether the joint surface has become arthritic. Early on, an MRI can detect dying bone before it is visible on an ordinary X-ray, and before it hurts much, which is part of why timing matters so much in this condition. It is worth knowing that avascular necrosis often affects both hips, so a scan of the painful side sometimes turns up quiet disease on the other, caught early enough to watch.

• Pre-collapse, early. The bone is compromised but the head is still round. This is the window where joint-preserving surgery has its best chance.
• Pre-collapse, later. Damage is more extensive but the surface has not yet broken. Preservation is still possible, with lower odds.
• Post-collapse. The head has flattened; mechanical symptoms and pain increase.
• Secondary arthritis. The joint surface is worn on both sides, and the hip now behaves like an arthritic hip.

Core decompression and other preservation procedures belong to the first stages; joint replacement belongs to the last.

Joint-preserving surgery before the head collapses

When the femoral head is still round, the goal is to save it. Core decompression, the most common preservation procedure, drills one or more channels into the dead area to relieve the raised pressure inside the bone and encourage new blood vessels to grow in. Surgeons sometimes add bone graft to support the area, or reposition the head with an osteotomy so that load falls on healthier bone.

These operations aim to delay or avoid replacement, which is especially valuable in younger patients who would otherwise face an artificial joint for many decades. Their success depends heavily on how much of the head is affected and on catching it before the surface flattens: a small early lesion has far better odds than an extensive one. They are not guaranteed to work: results vary, some hips progress to collapse anyway, and the evidence base is smaller than for hip replacement.

Conservative measures such as protected weight-bearing, activity modification, and exercise can ease symptoms while a plan is made, but they do not restore blood supply or reverse the process. Addressing a treatable underlying driver, where one exists, is part of the same picture, and is a reason to trace the cause rather than treat the hip in isolation.

Total hip replacement once the joint is damaged

After the head has collapsed or the joint has become arthritic, total hip replacement is the most reliable way to relieve pain and restore function. At that stage the hip behaves like any severely arthritic hip, for which orthopaedic guidelines recognize joint replacement as an established surgical option once nonsurgical measures no longer control symptoms 2Ref 2American Academy of Orthopaedic Surgeons (AAOS) (2023).Management of Osteoarthritis of the Hip — Clinical Practice Guideline.That AAOS's evidence-based hip osteoarthritis guideline recognizes surgical options such as joint replacement for an advanced arthritic hip alongside nonsurgical measures.. Hip osteoarthritis is managed nonsurgically first, with exercise, activity modification, and anti-inflammatory medication, and replacement is reserved for advanced disease 3Ref 3American Academy of Orthopaedic Surgeons (OrthoInfo) (2024).Osteoarthritis of the Hip.That hip osteoarthritis is initially managed nonsurgically with activity modification, exercise, and anti-inflammatory medication, with surgery reserved for advanced disease.. Structured exercise and education remain core measures for arthritic hip symptoms throughout 4Ref 4Bannuru RR, Osani MC, Vaysbrot EE, et al. (2019).OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis.That education and structured exercise are core treatments that relieve arthritic hip symptoms..

For avascular necrosis specifically, the wrinkle is age. Because the condition often strikes younger adults, an implant may need to last much longer than average, which raises the prospect of a future revision. That trade-off, saving the natural hip now versus a durable replacement later, is central to timing, and the question of whether to delay is worth reading in its own right: the case for and against choosing to wait to get a hip replacement turns on implant longevity and revision risk.

When surgery is clearly the right step

Avascular necrosis is one of the conditions where earlier surgical evaluation, rather than prolonged watchful waiting, is often the wiser course, precisely because the joint-preserving window closes once the head collapses. Surgery is clearly indicated when imaging confirms osteonecrosis with symptoms and the head is still salvageable, when there is progressive collapse, and when secondary arthritis has developed and pain limits daily life. In the salvageable window, preservation surgery is the priority; past it, replacement is.

None of this means rushing. It means the sequence of care here runs faster than for wear-and-tear arthritis: prompt imaging, an early specialist opinion, and a plan matched to the stage. Framed that way, surgery is a considered, stage-appropriate step, not a knife to avoid, and the reason evaluation should not be put off for months is that the best options depend on catching the hip before it caves.