What is osteonecrosis

Osteonecrosis (avascular necrosis, AVN) is the death of a section of bone tissue due to interrupted blood supply. Living bone constantly remodels; when blood flow stops, bone cells die, the structure breaks down, and ordinary loading triggers collapse — sinking of the joint surface.

Typical locations

Femoral head (most common). Femoral condyles (knee osteonecrosis). Humeral head. Talus. Scaphoid. Less often — vertebral body.

Risk groups

Men aged 30–50 — 4× more often than women. Bilateral in 40–80% (especially with systemic causes). Etiology unknown in 30%.

Why it's urgent

From early stage to collapse — often 6–18 months. After head collapse, restoration is impossible. Therefore, on suspicion — immediate MRI and urgent consultation.

Main causes

Glucocorticoids

Prolonged prednisolone or analog use (> 2 g cumulative). The most common non-traumatic cause. Often after COVID-19 courses, systemic disease, transplantation.

Alcohol

Chronic abuse alters fat metabolism and bone microcirculation. Risk is dose-dependent.

Trauma

Femoral neck fractures, hip dislocations, fractures of the talus and scaphoid disrupt end-arterial blood supply. May develop weeks to months after injury.

Hematologic disease

Sickle cell disease, antiphospholipid syndrome, thrombophilias, leukemia — disrupt microcirculation in marrow sinuses.

Decompression sickness

"Caisson disease" in divers and caisson workers. Gas emboli block bone capillaries.

Idiopathic

Unknown cause in 30%. A diagnosis of exclusion after ruling out all known factors.

ARCO stages

Stage 0 and I

Normal X-ray. MRI shows bone marrow edema and "double line." Clinically — load-related pain, possibly asymptomatic. MIBRAR® — maximum efficacy.

Stage II

X-ray shows sclerotic and lucent zones. Head shape preserved. Moderate pain. MIBRAR® — core decompression + BMAC, high efficacy.

Stage III

Subchondral fracture — "crescent sign." Beginning of collapse. Increasing pain. MIBRAR® feasible in early cases, often combined with orthopedic offloading.

Stage IV

Complete head collapse, acetabular changes, secondary arthrosis. Endoprosthesis indicated. MIBRAR® only as part of a comprehensive palliative approach.

Osteonecrosis diagnosis

MRI — method of choice

99% sensitivity at early stages, when X-ray is still normal. Detects bone marrow edema, "double line," first signs of necrosis. Mandatory on any suspicion.

X-ray

Not informative at early stages. Useful for stage II–IV: sclerosis, crescent sign, collapse. X-ray dynamics is a key progression criterion.

Lab screening

Cause identification: coagulation panel (thrombophilia), lipid profile, immune workup, systemic disease tests. Critical for preventing involvement of the second joint.

Osteonecrosis treatment with MIBRAR®

At stages I–III the key task is to restore blood supply and stimulate bone regeneration before collapse occurs. MIBRAR® combines surgical decompression with biologic product delivery.

Core decompression

Through a minimal access, channels are placed into the necrosis zone — intraosseous pressure drops, neoangiogenesis is initiated. 30–45 minute procedure.

BMAC into the necrosis zone

Bone marrow concentrate with mesenchymal and hematopoietic cells is delivered through the channels into the lesion. Stimulates new bone formation.

Orthopedic offloading

The first 6–12 weeks — crutches with partial weight-bearing. Protects the regeneration zone from mechanical disruption.

MRI monitoring

Repeat MRI at 3, 6, 12 months — assessing necrosis regression, ruling out progression. Repeat session if needed.

I–IIOptimal stages
60–80%Progression arrest
6–12 wkOffloading period
5–10 yrProsthesis postponement

Osteonecrosis is a time-critical diagnosis

On suspicion — urgent MRI and consultation. Don't wait for collapse.

Urgent consultation

Frequently asked questions

What is osteonecrosis?

Death of bone tissue due to interrupted blood supply. Without treatment — collapse and endoprosthesis.

What causes it?

Steroids, alcohol, trauma, coagulopathies, decompression sickness. 30% — idiopathic.

Can it be treated without surgery?

At I–II — yes. Core decompression + BMAC. At late stages with collapse — prosthesis.

What is core decompression?

Creating channels in the necrosis zone to lower pressure and stimulate regeneration. In MIBRAR®, augmented with BMAC.

How quickly to start?

As fast as possible. Early to late progression — 6–18 months. After collapse, restoration is impossible.