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Osteonecrosis of the femoral head (ONFH), also known as avascular necrosis of the femoral head (AVN), is a progressive orthopedic condition caused by impaired blood supply and disrupted bone remodeling within the femoral head. If the disease progresses to subchondral fracture and femoral head collapse, secondary hip osteoarthritis may develop and total hip arthroplasty (THA) may ultimately be required.
Early diagnosis is therefore critical. In patients with suspected early-stage ONFH, particularly younger patients with persistent hip or groin pain and normal or inconclusive X-rays, magnetic resonance imaging (MRI) is the most sensitive imaging modality for detecting early disease.
This comprehensive review summarizes the current clinical approach to ONFH etiology, diagnosis, MRI findings, ARCO staging, prognosis, hip-preserving procedures, bone grafting, biologic augmentation, and total hip arthroplasty, based on the expert consensus discussed in the source material.
Clinical note: Treatment decisions for ONFH should be individualized according to disease stage, lesion size and location, symptoms, femoral head structural integrity, comorbidities, and available surgical expertise.
ONFH frequently affects relatively young patients and may involve both hips.
Patients younger than 50 with persistent nontraumatic hip or groin pain and normal X-rays should be evaluated for possible ONFH when clinical risk factors are present.
MRI is highly sensitive for early ONFH when radiographs are normal or inconclusive.
Once ONFH is diagnosed in one hip, evaluation of the contralateral hip should be considered because bilateral disease is common.
ARCO staging helps classify disease severity and guide treatment planning.
Hip-preserving procedures generally have the greatest role before substantial femoral head collapse.
Core decompression remains an important hip-preserving procedure for selected symptomatic early-stage lesions.
Bone grafting, biologic augmentation, and osteotomy may be considered in selected patients, although their indications and evidence vary.
When femoral head structural failure, symptomatic collapse, acetabular degeneration, or failed hip-preserving treatment has occurred, total hip arthroplasty (THA) becomes an important treatment option.
Osteonecrosis of the femoral head is a condition in which compromised blood supply and impaired bone repair lead to progressive death of bone tissue within the femoral head.
The disease is more complex than simple ischemia. Current concepts describe ONFH as a multifactorial process involving vascular injury, increased intraosseous pressure, thrombosis or microvascular dysfunction, and impaired bone remodeling.
As structural damage progresses, the weakened subchondral bone may fracture and the femoral head may lose its normal spherical shape. Progressive collapse can then lead to secondary degenerative changes of the hip joint.
Excessive alcohol consumption and corticosteroid exposure are among the major risk factors associated with nontraumatic ONFH.
These factors may contribute to changes in intraosseous pressure, vascular function, lipid metabolism, and bone remodeling. The source material identifies alcohol exposure and corticosteroid use as major contributors to ONFH.
ONFH may also occur in association with systemic diseases and conditions that affect the microcirculation or coagulation system.
Reported associations include:
Sickle cell disease
Systemic lupus erythematosus
HIV infection
Coagulation abnormalities
Other systemic conditions associated with impaired vascular or bone health
Because ONFH may be multifocal, patients with relevant systemic risk factors may require assessment for osteonecrosis in other joints when clinically appropriate.
ONFH should be considered particularly in younger or middle-aged adults who develop persistent hip or groin pain without a clear traumatic cause.
Clinical suspicion should increase when hip pain occurs together with risk factors such as:
Long-term or significant corticosteroid exposure
Heavy alcohol consumption
Systemic inflammatory disease
Sickle cell disease
Other systemic conditions associated with vascular or coagulation abnormalities
The condition may affect both hips, and an asymptomatic lesion in the opposite hip is not uncommon.
The clinical presentation of ONFH can vary according to disease stage.
Common symptoms may include:
Persistent hip pain
Groin pain
Pain with weight-bearing activity
Progressive functional limitation
Reduced hip mobility in more advanced disease
An important clinical challenge is that early ONFH may produce symptoms while plain radiographs remain normal.
For this reason, a normal X-ray should not necessarily exclude ONFH when clinical suspicion remains high.
Diagnosis typically combines clinical assessment, risk-factor evaluation, plain radiographs, and MRI.
Standard anteroposterior and lateral hip radiographs are generally used as the initial imaging assessment.
Radiographs can help identify:
Sclerosis
Cystic changes
Loss of femoral head sphericity
Subchondral fracture
Femoral head collapse
Later degenerative changes
Oblique radiographic views may also help evaluate femoral head contour and structural integrity.
However, early ONFH may not be visible on X-rays.
When ONFH is strongly suspected despite normal or inconclusive radiographs, MRI is the preferred imaging modality for detecting early disease.
MRI can demonstrate:
The location of the necrotic lesion
Lesion size
Bone marrow abnormalities
The characteristic band surrounding the necrotic region
Subchondral and structural changes
Common MRI sequences include T1-weighted imaging and T2-weighted or STIR/fat-suppressed sequences.
A characteristic double-line sign may be seen on T2-weighted imaging in ONFH.
Yes. One of the major advantages of MRI is its ability to detect early osteonecrosis when conventional radiographs are still normal.
This makes MRI particularly important in patients with persistent symptoms and relevant risk factors.
Imaging findings may lag behind the initial exposure to certain risk factors. For example, MRI abnormalities may not immediately appear after corticosteroid exposure.
If clinical suspicion remains high, particularly during the first several months after significant corticosteroid exposure, repeat imaging may be considered.
CT can provide additional information about subchondral fracture and structural collapse, although its role is more limited for detecting very early disease.
MRI findings should always be interpreted in the context of the patient's age, symptoms, risk factors, and physical examination.
Conditions that may require differentiation from ONFH include:
This condition is particularly important in older adults. MRI may demonstrate a subchondral fracture line accompanied by more diffuse bone marrow edema.
Transient bone marrow edema can produce hip pain and MRI abnormalities that may resemble early ONFH.
Complex regional pain syndrome remains primarily a clinical diagnosis and cannot be reliably confirmed or excluded by MRI alone.
Therefore, imaging findings should not be interpreted in isolation.
Bilateral involvement is common in patients with ONFH.
When osteonecrosis is identified in one hip, evaluation of the contralateral hip, particularly with MRI, may identify an otherwise asymptomatic lesion.
Patients with systemic risk factors may also develop osteonecrosis at other skeletal sites. When multifocal osteonecrosis is suspected, MRI assessment of symptomatic joints may be appropriate.
The ARCO classification is widely used to describe the severity and structural progression of ONFH.
It is useful for prognosis and treatment planning, but staging should not be considered the sole determinant of treatment.
In Stage I ONFH:
Plain radiographs may appear normal.
MRI demonstrates abnormalities consistent with osteonecrosis.
A characteristic band around the necrotic area may be present.
Stage I represents an important window for considering hip-preserving strategies because substantial structural collapse has not yet occurred.
Stage II is characterized by radiographic abnormalities without femoral head collapse.
Possible findings include:
Bone sclerosis
Localized osteoporosis
Cystic changes
The overall spherical shape of the femoral head remains preserved.
Stage III indicates structural failure, including subchondral fracture and/or femoral head flattening.
It can be further divided into:
ARCO IIIA: collapse of approximately 2 mm or less
ARCO IIIB: collapse greater than 2 mm
The presence and extent of collapse are important prognostic factors.
Stage IV represents advanced degenerative disease, which may include:
Joint-space narrowing
Acetabular degenerative changes
Secondary hip osteoarthritis
At this stage, hip-preserving procedures are generally much less effective, and arthroplasty becomes an important consideration for symptomatic patients.
Disease stage alone does not fully describe the prognosis of ONFH.
Two particularly important factors are lesion size and lesion location.
Small, more medially located lesions may remain stable for prolonged periods.
By contrast, larger lesions involving the lateral weight-bearing portion of the femoral head are associated with a greater risk of structural collapse.
Larger necrotic lesions generally carry a higher risk of collapse.
Lesions involving more than approximately 30% of the femoral head have been associated with a particularly high structural failure risk in the source material.
Methods such as combined necrotic angle measurements and volumetric MRI assessment may be used to quantify lesion burden.
Ultimately, treatment planning should consider:
Symptoms
Lesion size
Lesion location
Femoral head sphericity
Subchondral integrity
Degree of collapse
Patient age and activity requirements
Associated systemic disease
Imaging findings should therefore support, rather than replace, individualized clinical decision-making.
Treatment depends primarily on the stage of disease, lesion characteristics, symptoms, and whether the femoral head remains structurally salvageable.
Broad treatment categories include:
Nonoperative management
Core decompression
Core decompression with biologic augmentation
Nonvascularized bone grafting
Vascularized bone grafting
Proximal femoral osteotomy
Total hip arthroplasty
The central clinical question is whether the femoral head can still be preserved or whether structural failure has progressed to the point where joint replacement is more appropriate.
Nonoperative treatment may be considered in selected patients, particularly those with:
Small lesions
Early-stage disease
Minimal or no symptoms
Significant medical contraindications to surgery
Activity modification and protected weight-bearing may be used to reduce mechanical stress on the femoral head.
However, protected weight-bearing should generally be considered an adjunct to observation or a surgical plan rather than a proven standalone method for preventing radiographic progression.
The role of medications and physical therapy remains dependent on the individual clinical situation and the available evidence.
Core decompression is one of the most frequently performed hip-preserving procedures for symptomatic, precollapse ONFH.
The procedure involves creating one or more channels into the affected portion of the femoral head.
The intended goals are to:
Reduce intraosseous pressure
Promote revascularization
Facilitate bone remodeling
Potentially delay structural collapse
The procedure is generally most suitable for selected patients with:
ARCO Stage I or II disease
Preserved femoral head sphericity
Small to moderate lesions
Lesions located primarily in medial or central regions
Symptoms attributable to ONFH
Larger lesions, particularly those involving the lateral weight-bearing region, have a higher risk of structural failure after core decompression.
Different technical approaches have been described, including variations in:
Drill diameter
Number of drilling channels
Trajectory
Graft or scaffold use
Biologic augmentation
No single technical modification has been consistently established as superior across all patients.
The choice of technique may depend on lesion characteristics, surgeon experience, and the biologic strategy being used.
Core decompression may be combined with biologic or cellular therapies intended to enhance bone regeneration and revascularization.
Potential adjuncts include:
Bone marrow aspirate concentrate (BMAC)
Bone marrow-derived mesenchymal stromal/stem cells (BMSCs)
Platelet-rich plasma (PRP)
Bone morphogenetic proteins (BMPs)
Cell-scaffold constructs
The proposed rationale is to increase local biological activity and support osteogenesis and angiogenesis beyond what decompression alone may achieve.
However, these approaches remain heterogeneous in terms of preparation, cell concentration, dosage, and clinical protocols.
Therefore, biologic augmentation should not automatically be considered standard treatment for every patient with ONFH.
Bone grafting can provide additional structural and biological support in selected patients with early disease.
Two broad categories are used:
Nonvascularized bone grafting
Vascularized bone grafting
Commonly described approaches include:
Phemister technique
Lightbulb technique
Trapdoor technique
These procedures generally involve removing necrotic bone and placing autologous bone, allograft material, or synthetic bone substitutes into the defect.
Nonvascularized bone grafting may be considered for:
ARCO Stage I to selected early Stage III disease
Moderate to large lesions
Early subchondral structural compromise
Patients in whom sufficient femoral head structure remains to support preservation
Reported medium- to long-term survival in selected series has been approximately 70%–80%, although outcomes depend substantially on disease stage, lesion characteristics, patient factors, and surgical technique.
Vascularized bone grafting combines structural support with restoration of blood supply.
Examples include:
Free vascularized fibular grafts
Vascularized iliac crest grafts
Pedicled muscle or trochanteric grafts
Vascularized bone grafting may be considered in carefully selected younger patients with ARCO Stage I–III disease, including some patients with early collapse.
Important limitations include:
Greater technical complexity
Longer operative time
Requirement for specialized surgical expertise
Need for appropriate microsurgical resources in some procedures
Potential donor-site complications
Limited availability outside specialized centers
Reported survival rates in appropriately selected patients have generally been in the range of 60%–80% in the source material.
Proximal femoral osteotomy aims to redistribute mechanical loading away from the necrotic portion of the femoral head.
By repositioning the viable portion of the femoral head into the principal weight-bearing region, the procedure attempts to reduce mechanical stress on the necrotic area and delay collapse.
Potential candidates generally require:
Early-stage ONFH
A localized lesion that can be moved away from the primary weight-bearing region
Adequate viable bone for load redistribution
Preserved articular cartilage
Osteotomy can substantially alter proximal femoral anatomy.
This is important because subsequent total hip arthroplasty may become technically more difficult after previous osteotomy.
Reported survival rates in highly selected patient series have been approximately 50%–70% at moderate follow-up.
The procedure has become less common in North America and Europe but continues to be used more frequently in some Asian clinical settings.
Total hip arthroplasty (THA) is an established treatment for symptomatic ONFH with advanced structural damage.
Common indications include:
Femoral head collapse
Subchondral fracture
Acetabular degeneration
Progressive functional limitation
Failed hip-preserving procedures
Loss of femoral head structural integrity
When the femoral head is no longer mechanically salvageable, THA can provide substantial pain relief and functional improvement.
Not necessarily.
Femoral head collapse substantially reduces the durability of many hip-preserving procedures, particularly when collapse is associated with subchondral fracture or acetabular involvement.
However, the decision to proceed with THA should consider:
Symptoms
Functional limitation
Radiographic findings
Patient age
Comorbidities
Previous surgery
Patient preferences
Overall joint condition
Therefore, femoral head collapse should be interpreted within the complete clinical context rather than treated as an automatic indication for arthroplasty.
Modern implant design, bearing surfaces, fixation methods, and surgical techniques have substantially improved THA outcomes in patients with ONFH.
Contemporary series and registry data cited in the source material report approximately 89%–98% 10-year implant survival.
Advances in:
Ceramic bearing surfaces
Highly cross-linked polyethylene
Implant fixation
Femoral head design
have contributed to improved durability.
However, ONFH patients may have additional risk factors, including systemic disease, compromised bone quality, and previous hip-preserving procedures.
These factors can affect the risks of:
Dislocation
Revision surgery
Infection
Mechanical complications
Careful preoperative assessment and optimization are therefore important.
Implant selection should be individualized according to:
Patient age
Bone quality
Femoral head and acetabular anatomy
Previous hip-preserving procedures
Risk of instability
Surgical anatomy
Cementless fixation is commonly used and may provide reliable biological fixation in appropriate patients.
Ceramic-on-highly-cross-linked polyethylene bearings are frequently considered because of their low wear characteristics and potential long-term durability.
Patients with bone loss, altered anatomy, or previous reconstruction may require specialized stems or fixation strategies.
In patients at increased risk of instability, larger femoral heads or dual-mobility constructs may be considered.
| Treatment | Typical Disease Stage | Main Principle | Key Advantages | Important Limitations |
|---|---|---|---|---|
| Core decompression | ARCO I–II | Reduce intraosseous pressure and promote revascularization | Reproducible, relatively low morbidity, preserves future options | Less effective for large or lateral lesions |
| Core decompression + biologic augmentation | Selected ARCO I–II | Add cellular or biologic stimulation | May improve healing in selected patients | Evidence and protocols remain heterogeneous |
| Nonvascularized bone grafting | ARCO I–III, selected early collapse | Provide structural and biological support | Greater structural support than decompression alone | More invasive; outcomes decrease with advanced collapse |
| Vascularized bone grafting | ARCO I–III | Restore blood supply and provide structural support | Combines biological and mechanical support | Technically demanding and resource intensive |
| Proximal femoral osteotomy | Selected early disease | Redistribute mechanical load | Changes loading without grafting | Alters proximal femoral anatomy and may complicate future THA |
| THA | Advanced collapse/arthritis | Replace damaged joint surfaces | Reliable pain and functional improvement | Joint replacement rather than femoral-head preservation |
The reported survival ranges should be interpreted as approximate estimates from selected clinical series rather than guaranteed outcomes for individual patients.
The source material provides the following major clinical recommendations.
Recommendation 1: MRI should be considered in patients younger than 50 years who have persistent nontraumatic hip pain, normal or suspicious radiographs, and clinical suspicion of ONFH.
Recommendation 2: MRI evaluation of the contralateral hip should be considered after ONFH is diagnosed because bilateral disease is common.
Recommendation 3: Plain radiographs remain important even when MRI is available because they help evaluate femoral head shape and structural integrity.
Recommendation 4: Lesion size and location should be incorporated into treatment planning because larger lesions involving the lateral weight-bearing region have a higher risk of collapse.
Recommendation 5: Nonoperative management may be considered for small, asymptomatic precollapse lesions, although it cannot reliably prevent progression in most patients.
Recommendation 6: Routine use of bisphosphonates as disease-modifying therapy is not recommended because evidence for structural benefit remains inconsistent.
Recommendation 7: Core decompression is recommended for selected symptomatic ARCO I–II lesions with preserved femoral head sphericity, particularly small to moderate lesions.
Recommendation 8: Biologic augmentation may be considered in selected early-stage lesions, although its long-term disease-modifying benefit remains uncertain.
Recommendation 9: Nonvascularized or vascularized bone grafting may be considered when the femoral head remains structurally salvageable, particularly in appropriately selected younger patients treated at experienced centers.
Recommendation 10: Proximal femoral osteotomy may be considered for carefully selected early lesions when lesion geometry permits effective redistribution of mechanical loading.
Recommendation 11: THA is recommended for symptomatic femoral head collapse, acetabular degeneration, or failure of hip-preserving treatment.
BMAC may provide mesenchymal progenitor cells, growth factors, and cytokines that could support angiogenesis and bone formation.
Some observational studies and meta-analyses have reported improvements in pain and function and lower rates of progression or conversion to THA in selected early-stage lesions.
However, significant variation exists in cell concentration and preparation methods, and long-term randomized evidence remains limited.
Expanded BMSCs are intended to provide a higher number of targeted cells capable of supporting osteogenesis and angiogenesis.
Some studies have reported potentially better imaging and clinical outcomes than core decompression alone, but clinical protocols remain heterogeneous and regulatory considerations limit widespread standardized use.
PRP provides growth factors that may influence angiogenesis, inflammation, and tissue healing.
Small clinical series have reported symptomatic improvement, but the structural disease-modifying benefit remains uncertain.
BMPs can stimulate osteogenic differentiation and bone formation.
Experimental and limited clinical studies suggest that BMPs may enhance bone regeneration when combined with decompression or grafting, but cost, regulatory considerations, variable clinical evidence, and potential complications remain important limitations.
Cell-scaffold approaches combine biological stimulation with structural support.
Early research suggests potential benefits in selected lesions, but long-term clinical evidence remains limited.
Allogeneic cell-based approaches are being investigated as a potential way to provide standardized cell products without autologous donor-site procedures.
However, clinical experience remains limited and immunologic and regulatory considerations remain important.
Important: Biologic augmentation should currently be viewed as an adjunctive or investigational strategy in many clinical settings rather than a universally established standard treatment.
A practical treatment framework can be based on four major questions:
Symptoms and functional impairment should be considered together with imaging findings.
Small, asymptomatic lesions may sometimes be observed, whereas persistent symptoms may justify more active treatment.
Precollapse disease generally provides the greatest opportunity for hip-preserving treatment.
Once substantial subchondral fracture or collapse has developed, the durability of preservation procedures decreases.
Small, central or medial lesions may have a different prognosis from large lesions involving the lateral weight-bearing region.
This is one of the most important considerations when deciding between hip-preserving surgery and arthroplasty.
A treatment algorithm should therefore integrate:
Symptoms → ARCO stage → lesion size → lesion location → structural integrity → patient factors → treatment selection
Plain hip radiographs are commonly used as the initial imaging assessment. However, early ONFH may not be visible on X-rays. When clinical suspicion remains high, MRI is highly sensitive for early disease.
Yes. Early-stage ONFH can have normal radiographs while MRI already demonstrates characteristic abnormalities.
Bilateral involvement is common. Therefore, assessment of the opposite hip may be considered after ONFH is identified in one hip.
Treatment depends on lesion size, location, symptoms, ARCO stage, and structural integrity. Core decompression is an important hip-preserving option for selected symptomatic ARCO I–II lesions.
Core decompression may delay or prevent progression to THA in appropriately selected early-stage patients, but outcomes vary substantially according to lesion characteristics and disease stage. It is not guaranteed to prevent future hip replacement.
THA is commonly considered when symptomatic ONFH has progressed to femoral head structural failure, substantial collapse, acetabular degeneration, or when hip-preserving procedures have failed.
No. Collapse significantly affects prognosis and reduces the durability of many hip-preserving procedures, but treatment should still be individualized according to symptoms, function, structural damage, patient factors, and overall joint condition.
Osteonecrosis of the femoral head is a multifactorial disease involving vascular injury, impaired bone remodeling, and progressive structural failure.
The most important principles of contemporary ONFH management are early diagnosis, accurate staging, assessment of lesion size and location, evaluation of femoral head structural integrity, and individualized treatment planning.
MRI plays a particularly important role in detecting early disease when radiographs are normal. ARCO staging provides a useful framework for describing disease progression, but treatment decisions should not rely on staging alone.
For selected patients with precollapse disease, hip-preserving procedures such as core decompression and bone grafting may help preserve the femoral head. Biologic augmentation represents an evolving area of research, while vascularized grafting and osteotomy remain specialized options for carefully selected patients.
When the femoral head can no longer maintain its mechanical integrity, particularly in the presence of symptomatic collapse or acetabular degeneration, total hip arthroplasty provides an established option for pain relief and functional restoration.
Future advances in ONFH management will likely depend on better risk stratification, standardized disease classification, prospective multicenter research, registry-based outcomes, improved imaging and biological technologies, and a deeper understanding of disease mechanisms in high-risk populations.
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