Views: 0 Author: Site Editor Publish Time: 2026-08-14 Origin: Site
Nontraumatic osteonecrosis of the femoral head (ONFH), also known as avascular necrosis (AVN) of the femoral head, is a progressive orthopedic condition that can lead to femoral head collapse, secondary osteoarthritis, severe hip pain and ultimately total hip arthroplasty (THA).
The clinical challenge is particularly important in younger adults because the disease may progress for years before joint collapse occurs. Early diagnosis and appropriate staging can therefore determine whether a patient remains a candidate for hip-preserving treatment or requires joint replacement.
In 2026, Edward Y. Cheng, Alireza Mirzaei, Stuart B. Goodman, Quanjun Cui, Michael A. Mont, Lynne C. Jones and the ARCO Clinical Practice Guideline Workgroup published an international evidence-based clinical practice guideline for nontraumatic ONFH in The Journal of Bone and Joint Surgery. The guideline was developed using systematic evidence review and the GRADE framework and represents an important effort to standardize diagnosis and treatment recommendations internationally.
This article summarizes the major clinical recommendations and discusses how imaging, ARCO stage, femoral head collapse and patient factors influence treatment selection.
Clinical note: This article is an educational summary of the 2026 international guideline and is not a substitute for individualized medical evaluation or surgical decision-making.
Nontraumatic osteonecrosis of the femoral head occurs when the blood supply to the femoral head is compromised, resulting in progressive death of bone tissue.
As the disease progresses, weakened subchondral bone may develop a subchondral fracture, followed by femoral head collapse and secondary degenerative changes of the hip joint.
The clinical course can therefore be broadly understood as:
Vascular compromise → bone necrosis → structural weakening → subchondral fracture → femoral head collapse → secondary osteoarthritis
The disease can be symptomatic or asymptomatic, and its progression varies considerably according to lesion size, location, stage and underlying risk factors
Nontraumatic ONFH frequently affects relatively young and middle-aged adults.
Important risk factors include:
Long-term or high-dose corticosteroid exposure
Chronic alcohol consumption
Systemic lupus erythematosus and other autoimmune disorders
Hyperlipidemia and metabolic abnormalities
Coagulation disorders
Organ transplantation
Smoking
Genetic susceptibility
A 2026 JBJS update emphasizes that ONFH should be considered particularly in patients younger than 50 years who have persistent hip pain despite apparently normal radiographs.
Because bilateral involvement is relatively common, evaluation of the contralateral hip with MRI may also be appropriate when ONFH is suspected.
The most important distinction in ONFH management is whether the femoral head has undergone structural collapse.
Before collapse, joint-preserving procedures may have the potential to delay progression and preserve the native hip.
After collapse, however, the mechanical integrity of the femoral head has already been compromised, making reliable joint preservation considerably more difficult.
Therefore, the treatment pathway can generally be divided into:
Potential options include:
Observation in selected patients
Core decompression
Core decompression with bone marrow concentrate
Vascularized fibular grafting
Selected osteotomy procedures
Other investigational or adjunctive treatments
Treatment increasingly shifts toward:
Joint-preserving procedures in carefully selected younger patients
Total hip arthroplasty when structural damage is advanced
The 2026 guideline emphasizes that treatment selection should incorporate disease stage, symptoms, lesion characteristics, patient age, life expectancy and patient preferences.
One of the clearest recommendations from the international guideline concerns MRI.
MRI is recommended as the preferred imaging modality for diagnosing ONFH.
Reported diagnostic performance in the guideline includes approximately:
Sensitivity: 91%
Specificity: 96%
The evidence quality was rated very low, but the recommendation was strong because of the consistency of expert judgment and the clinical advantages of MRI.
MRI can identify early disease that may not yet be visible on conventional radiographs.
A characteristic finding is the double-line sign, which can support the diagnosis of ONFH.
No ionizing radiation
High sensitivity for early disease
Detection of bone marrow abnormalities
Assessment of lesion extent
Evaluation of bilateral hip involvement
Detection of bone marrow edema
Assessment of subchondral abnormalities
However, MRI availability, cost, contraindications and patient tolerance remain practical limitations.
The presence of a subchondral fracture is particularly important because it can distinguish earlier-stage disease from disease that has entered the collapse phase.
The international guideline suggests that CT or MRI is preferable to conventional radiography for detecting subchondral fractures, although the strength of evidence is weak.
CT may be particularly useful when a fracture is suspected but is not clearly demonstrated on radiographs or MRI.
High spatial resolution
Rapid acquisition
Excellent visualization of cortical and subchondral bone
Useful for identifying subtle structural collapse
No radiation
Bone marrow assessment
Soft-tissue evaluation
Better assessment of early osteonecrosis
Therefore, CT and MRI should not necessarily be viewed as competing technologies. In selected cases, they provide complementary information.
MRI can also be used to monitor ONFH over time.
The guideline suggests that MRI can quantify the:
Size of the necrotic lesion
Extent of involvement
Changes in the lesion over time
Response to treatment
However, an important limitation remains: there is no universally established threshold defining what constitutes a clinically meaningful change in MRI lesion size.
Therefore, MRI findings should be interpreted together with:
Pain
Hip function
Structural progression
Subchondral fracture
Femoral head sphericity
Radiographic staging
rather than used as an isolated treatment endpoint.
An important clinical problem is determining whether an imaging abnormality is actually responsible for the patient's hip pain.
The guideline highlights bone marrow edema (BME) as a more useful indicator of symptomatic disease than joint effusion.
The reported positive likelihood ratios were approximately:
BME: 16.2
Joint effusion: 3.3
BME was found in approximately 62.7% of symptomatic patients compared with 1.8% of asymptomatic patients.
This suggests that MRI can provide not only diagnostic information but also valuable information about the clinical relevance of ONFH.
Treatment should not be based simply on whether ONFH is present.
The ARCO stage is central to treatment planning.
A simplified clinical framework is:
| Disease status | Typical clinical implication |
|---|---|
| ARCO I | Early/pre-radiographic disease |
| ARCO II | Radiographic disease without collapse |
| ARCO III | Subchondral fracture and/or femoral head collapse |
| ARCO IV | Collapse with secondary osteoarthritis |
The most important practical dividing line is often whether subchondral fracture or collapse has occurred.
The main objective is:
Preserve the femoral head and delay structural failure.
The objective increasingly becomes:
Restore pain-free hip function and address structural joint destruction.
Core decompression (CD) remains one of the most established joint-preserving procedures for early ONFH.
The 2026 guideline states that core decompression may be considered for patients with ARCO I-II disease.
The theoretical objectives of core decompression include:
Reducing intraosseous pressure
Removing necrotic bone
Creating a channel for vascular and bone regeneration
Potentially delaying femoral head collapse
However, outcomes are strongly influenced by:
Disease stage
Lesion size
Lesion location
Presence or absence of subchondral fracture
Patient characteristics
Therefore, core decompression should not be considered equally effective for every ONFH lesion.
One of the more important findings in the guideline concerns augmentation of core decompression with bone marrow concentrate (BMC).
For patients undergoing core decompression, adding BMC may reduce the risk of femoral head collapse.
The reported meta-analysis showed a relative risk of collapse of approximately:
1.82 (95% CI 1.21–2.74; P = 0.0042) when comparing CD with CD+BMC in the analysis framework reported by the guideline.
The estimated absolute reduction in risk was approximately 26%, although the overall evidence quality remained limited.
Biological augmentation
Potential enhancement of bone regeneration
Reduced collapse risk in selected patients
Additional equipment
Increased procedural complexity
Additional cost
Variable cell concentration and preparation methods
Limited high-quality comparative evidence
Consequently, CD+BMC may be considered, but it should not yet be interpreted as a universally superior treatment.
Vascularized fibular grafting (VFG) is another femoral head-preserving option for selected ARCO I-II patients.
The guideline reports observational evidence suggesting a five-year collapse rate of approximately 13% in several series. However, these studies are predominantly single-arm observational studies, and high-quality comparative evidence is limited.
Potential advantages include:
Structural support
Biological revascularization
Potential preservation of the femoral head
However, VFG is technically demanding and resource intensive.
Potential disadvantages include:
Longer surgical procedures
Donor-site morbidity
Greater surgical complexity
Need for specialized expertise
Therefore, VFG is generally best reserved for carefully selected patients treated at experienced centers.
Proximal femoral osteotomy can theoretically redistribute mechanical loading away from necrotic bone toward relatively healthy portions of the femoral head.
The guideline states that osteotomy may occasionally be considered in ARCO I-II disease, but evidence quality is very low.
A major limitation is that osteotomy may:
Alter proximal femoral anatomy
Create deformity
Complicate future THA
Increase technical complexity of subsequent reconstruction
Thus, although osteotomy remains a potential joint-preserving procedure, it requires highly individualized decision-making.
The guideline does not recommend adding nonvascularized autologous fibular grafting to core decompression for routine prevention of femoral head collapse.
The available evidence has not demonstrated a clear benefit, while harvesting the fibula introduces additional morbidity.
This is an important example of why newer or more technically complex procedures should not automatically be considered better.
Many other treatments have been investigated for early ONFH, including:
Bisphosphonates
Autologous mesenchymal stem cells
Platelet-rich plasma (PRP)
Bone morphogenetic proteins (BMP)
Porous tantalum implants
Extracorporeal shock-wave therapy
Pulsed electromagnetic field therapy
Hyperbaric oxygen therapy
However, the guideline found insufficient qualifying evidence to make routine recommendations for many of these approaches.
This does not necessarily mean that these technologies are ineffective.
Rather, it indicates that the current evidence base is insufficient to support a strong standardized recommendation.
This distinction is particularly important when interpreting emerging orthopedic technologies.
This remains one of the most difficult clinical questions.
Some patients with early ONFH have no symptoms but may later develop pain or femoral head collapse.
The guideline therefore supports individualized decision-making rather than automatic intervention.
Factors to consider include:
ARCO stage
Lesion size
Lesion location
Risk of collapse
Patient age
Occupation
Activity level
Underlying disease
Patient preferences
Larger and more laterally located lesions generally have a greater risk of progression.
Therefore:
Asymptomatic does not necessarily mean low risk.
But it also does not mean every asymptomatic lesion requires surgery.
For symptomatic ARCO I-II disease without subchondral fracture or collapse, the guideline recommends considering alternatives to THA.
The rationale is particularly important in younger patients.
If the femoral head remains structurally preserved, a successful joint-preserving procedure may delay or avoid arthroplasty.
This is clinically meaningful because younger patients have a longer lifetime during which they may be exposed to:
Implant wear
Periprosthetic fracture
Infection
Dislocation
Revision surgery
Therefore, hip preservation is particularly valuable when the disease is diagnosed before structural collapse.
Once subchondral fracture or femoral head collapse occurs, treatment becomes considerably more challenging.
For ARCO III disease, the guideline indicates that joint-preserving procedures generally provide less predictable functional improvement than THA. Nevertheless, hip preservation may still be considered in selected younger patients.
The decision should consider:
Degree of collapse
Lesion location
Acetabular cartilage condition
Patient age
Functional demands
Expected longevity
Surgical expertise
Patient preference
This is an ideal setting for shared decision-making.
For advanced disease with femoral head collapse and secondary joint degeneration, total hip arthroplasty remains the most predictable reconstructive option.
The 2026 guideline notes that THA generally provides better functional outcomes than hip-preserving procedures in advanced disease.
A recent 2026 JBJS review similarly emphasizes that total hip arthroplasty remains the most reliable treatment after femoral head collapse.
THA can address:
Femoral head collapse
Severe pain
Secondary osteoarthritis
Loss of hip mobility
Functional limitation
However, implant longevity remains an important consideration in younger patients.
A practical decision framework can be summarized as follows:
| Clinical situation | General treatment direction |
|---|---|
| ARCO I-II, small lesion, asymptomatic | Observation may be appropriate |
| ARCO I-II, symptomatic, pre-collapse | Consider joint-preserving treatment |
| ARCO I-II with high-risk lesion | Consider active hip-preservation strategy |
| ARCO III, limited collapse, young patient | Individualized hip preservation vs THA |
| ARCO III-IV with advanced collapse/arthritis | THA generally more predictable |
| Failed hip-preserving procedure | THA may become necessary |
This is not a substitute for clinical decision-making, but it illustrates the fundamental principle:
The earlier the disease is identified, the greater the opportunity for femoral head preservation.
The guideline emphasizes that treatment should not be determined by radiographic stage alone.
Patient longevity is particularly relevant.
A younger patient may reasonably accept a technically demanding hip-preserving procedure if it can postpone THA.
Conversely, an older patient with advanced disease may benefit more from the predictable functional improvement associated with arthroplasty.
Therefore, the risk-benefit balance changes throughout the patient's lifetime.
This guideline is important because it was developed as an international evidence-based clinical practice guideline led by ARCO.
The development process incorporated:
Systematic literature review
GRADE methodology
PICO-based clinical questions
Multidisciplinary expert input
International collaboration
Modified Delphi consensus
External review
The guideline was developed by experts from multiple countries and institutions and was published in The Journal of Bone and Joint Surgery in 2026.
The guideline therefore attempts to reduce variation in ONFH management and provide a common evidence-based framework for clinicians internationally.
Several important research questions remain unanswered.
Future studies should directly compare:
MRI
CT
Conventional radiography
Quantitative imaging techniques
particularly for early disease and subchondral fracture detection.
Researchers need validated thresholds for determining whether a change in necrotic lesion size represents a clinically meaningful response.
Randomized trials comparing observation with early intervention could clarify which asymptomatic lesions benefit from treatment.
Cell therapy, PRP, BMP and other regenerative approaches remain promising but require larger, better-designed clinical trials.
Future ONFH management will likely combine:
ARCO stage + lesion size + lesion location + imaging biomarkers + patient age + biological risk factors
rather than relying on staging alone.
Osteonecrosis of the femoral head is a condition caused by compromised blood supply to the femoral head, resulting in bone death and potentially progressive structural collapse.
Important risk factors include corticosteroid exposure, chronic alcohol consumption, autoimmune diseases, metabolic disorders, coagulation abnormalities, organ transplantation, smoking and genetic susceptibility.
According to the 2026 international guideline, MRI is the preferred imaging modality for diagnosing ONFH because of its high sensitivity and ability to identify early disease.
Yes. When ONFH is diagnosed before femoral head collapse, joint-preserving procedures such as core decompression may be considered in appropriately selected patients.
Core decompression may be considered for ARCO I-II disease. Outcomes depend strongly on disease stage, lesion characteristics and patient selection.
The guideline indicates that adding bone marrow concentrate to core decompression may reduce the risk of femoral head collapse, although the overall evidence quality remains limited.
THA becomes increasingly appropriate when femoral head collapse, secondary arthritis or advanced structural damage makes preservation unlikely to provide predictable long-term results.
Yes. Selected asymptomatic ARCO I-II lesions may be monitored, but lesion size, location and risk of progression should be carefully considered.
Yes. Bilateral involvement is common, and MRI evaluation of the contralateral hip may be appropriate when ONFH is suspected.
Nontraumatic osteonecrosis of the femoral head remains a challenging orthopedic disease, particularly because it frequently affects younger and working-age adults.
The new 2026 international evidence-based clinical practice guideline led by ARCO and published in JBJS provides an important framework for standardizing diagnosis and treatment.
MRI has a central role in early diagnosis, while CT and MRI can help identify subchondral fractures that influence staging and treatment decisions.
For pre-collapse ONFH, joint-preserving procedures such as core decompression remain important options in carefully selected patients. Bone marrow concentrate may provide additional biological benefits, although stronger evidence is still required.
Once femoral head collapse and advanced joint degeneration occur, total hip arthroplasty remains the most predictable reconstructive treatment.
Ultimately, successful ONFH management depends on early diagnosis, accurate staging, appropriate patient selection and individualized treatment planning.
Cheng EY, Mirzaei A, Goodman SB, Cui Q, Mont MA, Jones LC; ARCO Clinical Practice Guideline Workgroup. Nontraumatic Osteonecrosis of the Femoral Head: An International Evidence-Based Clinical Practice Guideline. J Bone Joint Surg Am. 2026;108(12):903-906. doi:10.2106/JBJS.25.01616.
Cheng EY, Mirzaei A, Goodman SB, Cui Q, Mont MA, Jones LC; ARCO Clinical Practice Guideline Workgroup. Nontraumatic Osteonecrosis of the Femoral Head: An International Evidence-Based Clinical Practice Guideline. J Arthroplasty. 2026. doi:10.1016/j.arth.2026.03.056.
Parikh R, et al. Diagnosis and Treatment of Nontraumatic Osteonecrosis of the Femoral Head: A Systematic Review and Meta-Analyses for the ARCO Clinical Practice Guideline Development Workgroup. 2026.
Mont MA, Smitterberg CW, Jones LC, Goodman SB, Lieberman JR, Parvizi J, Cheng EY. Nontraumatic Osteonecrosis of the Femoral Head: An Update. J Bone Joint Surg Am. 2026. doi:10.2106/JBJS.25.01621.
Association Research Circulation Osseous (ARCO). Clinical Practice Guidelines for Osteonecrosis of the Femoral Head. 2026.
JBJS 2026 International Guideline for Nontraumatic Osteonecrosis of the Femoral Head
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