From radiological stability to functional preservation: Reconsidering the value of conservative treatment for osteonecrosis of the femoral head

Abstract

Conservative treatment for osteonecrosis of the femoral head has long been debated due to inconsistent outcomes and limited clarity regarding its appropriate indications. The study by Chen et al, published in World Journal of Orthopedics, provides valuable long-term evidence demonstrating that radiological stability can translate into meaningful functional preservation in selected patients. This editorial re-examines the clinical value of conservative hip preservation by linking imaging-based progression patterns with long-term functional trajectories. Key considerations – such as stage-specific evaluation, patient selection, and predictors of treatment durability – are highlighted to refine clinical decision-making. A deeper understanding of the interaction between imaging stability and functional outcomes may reshape future treatment algorithms for osteonecrosis of the femoral head.

Key Words: Collapse progression; Non-surgical management; Radiological-functional correlation; Osteonecrosis of the femoral head; Conservative hip preservation

Core Tip: Conservative treatment for osteonecrosis of the femoral head has long been limited by inconsistent outcomes and unclear indications. Emerging long-term evidence demonstrates that radiological stability – particularly in patients with limited lesion extent and minimal collapse – can translate into durable functional preservation. This editorial synthesizes multisource data to re-evaluate the role of conservative management, emphasizing stage-specific assessment, precise patient selection, and predictors of treatment durability. A deeper integration of imaging progression patterns with functional trajectories may refine future therapeutic algorithms and support a more individualized approach to hip preservation.

This editorial refers to "Outcomes of the conservative hip preservation treatment in patients with osteonecrosis of the femoral head: With 4-year follow-up" by Chen et al, 2025; https://dx.doi.org/10.5312/wjo.v16.i12.110291.

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INTRODUCTION

Osteonecrosis of the femoral head (ONFH) is a debilitating disorder that can lead to hip pain, functional impairment, and ultimately joint destruction, and it predominantly affects young and middle-aged adults[1]. Its development is associated with glucocorticoid exposure, alcohol consumption, trauma, and a range of metabolic or circulatory abnormalities[2]. During disease progression, some patients develop femoral head collapse, followed by secondary osteoarthritis, and may ultimately require total hip arthroplasty[3]. Although contemporary total hip arthroplasty can provide reliable pain relief and functional restoration, the limited longevity of prosthetic implants, the risk of long-term revision, and the demand for postoperative activity remain important concerns, particularly in young, highly active patients or those with a long life expectancy[4,5]. Therefore, delaying or avoiding arthroplasty in appropriately selected patients, while preserving the native hip joint as far as possible, remains a central objective in the management of ONFH.

However, conservative treatment for ONFH remains contentious. Previous studies have largely assessed its efficacy using radiographic progression, the extent of femoral head collapse, or conversion to surgical intervention as principal endpoints. Yet radiographic changes and long-term functional outcomes do not always align[6-8]. In other words, mild collapse or limited radiographic progression does not necessarily signify functional failure of the hip, nor does it invariably mandate immediate arthroplasty[9,10]. Thus, balancing imaging findings, symptom burden, functional status, and the timing of surgery remains a central challenge in contemporary clinical decision-making for ONFH.

In this context, the study by Chen et al[11], published in World Journal of Orthopedics, provides valuable insight. With a mean follow-up of more than 4 years, the authors found that among 119 hips managed with conservative hip-preserving treatment, 90.76% did not progress to surgical intervention, suggesting that, in carefully selected patients, conservative management may enable a substantial proportion to maintain satisfactory hip function and avoid or defer surgery[11]. These findings invite a reconsideration of conservative treatment: Rather than being viewed simply as “passive waiting”, it should be understood as an individualized hip-preserving strategy guided by disease stage, lesion extent, degree of collapse, and functional status.

WHAT DOES THE IN-PRESS STUDY ADD TO CURRENT KNOWLEDGE?

The principal contribution of the study by Chen et al[11], published in World Journal of Orthopedics, is that conservative treatment was not assessed solely through the lens of imaging progression; rather, the authors used long-term follow-up to examine both progression to surgical intervention and the durability of functional preservation. Over a mean follow-up of more than 4 years, 90.76% of the 119 affected hips did not progress to surgery, suggesting that conservative treatment may achieve a high rate of functional preservation in appropriately selected patients with ONFH[11]. This finding is important for reappraising the clinical value of conservative management, as it indicates that conservative treatment is not necessarily synonymous with “delayed failure”, but may instead support sustained functional maintenance in specific patient subgroups.

Similarly, Osawa et al[12] followed patients with ONFH undergoing conservative treatment for more than 3 years and found that, when femoral head collapse remained within 3 mm, patients could still achieve sustained improvement in hip function, with a markedly reduced risk of secondary osteoarthritis. This finding suggests that mild collapse does not necessarily signify failure of conservative treatment. Rather, the key considerations are the degree of collapse, lesion extent, involvement of the weight-bearing region, and whether functional status remains within a clinically manageable range[13,14].

Therefore, although total hip arthroplasty often provides more rapid and reliable pain relief and functional restoration in patients with substantial collapse or advanced ONFH, its advantage in improving quality of life may not be absolute for patients with early-stage disease, no collapse, or only mild collapse with controllable symptoms. Conversely, premature arthroplasty must be weighed against the finite longevity of prosthetic implants, the risk of long-term revision, and the sustained activity demands of young patients[15]. From this perspective, the benefits of conservative treatment in rigorously stratified and standardizedly managed patients should not be viewed merely as delaying disease progression, but rather as achieving clinically meaningful functional preservation over a defined period.

CONSERVATIVE TREATMENT SHOULD BE UNDERSTOOD AS SELECTIVE FUNCTIONAL PRESERVATION

From an etiological perspective, consistent evidence is currently lacking to support etiology alone as an independent determinant of conservative treatment outcomes. Rather, etiology may exert an indirect influence by shaping the tempo of disease progression, lesion extent, and individual response to treatment. For example, in glucocorticoid-associated ONFH, early dose reduction or discontinuation of glucocorticoids may, to some extent, modify disease progression[16]. However, in routine clinical practice, many patients already present at a defined stage of disease, and etiology alone is rarely sufficient to determine whether conservative treatment is appropriate.

Similarly, age, sex, and bilateral involvement should not be considered in isolation as determinants of the success or failure of conservative treatment. Rather, they more often reflect differences in overall disease burden, functional demands, and therapeutic goals. For example, younger patients may wish to delay arthroplasty, yet they may also have greater activity requirements; patients with bilateral involvement may face more complex challenges in weight-bearing management and functional limitation. Therefore, treatment decisions for ONFH should be guided by a comprehensive assessment of lesion extent, disease stage, degree of collapse, and functional status, rather than by any single clinical indicator.

RADIOLOGICAL PROGRESSION DOES NOT ALWAYS INDICATE CLINICAL FAILURE

The relationship between imaging findings and the necessity for surgery has long been a central controversy in clinical decision-making for ONFH. The study by Chen et al[11] suggests that, even when some patients develop a degree of radiographic collapse during follow-up, most do not immediately progress to arthroplasty; in particular, those with mild collapse may still maintain relatively stable hip function. These findings indicate that, although radiographic progression remains clinically important, it should not be equated simplistically with functional failure or regarded as an absolute indication for immediate surgery.

A key explanation for this phenomenon is the marked heterogeneity among patients with ONFH in the degree of collapse, disease stage, extent of necrosis, lesion location, and symptom burden. Radiographic progression and clinical symptoms do not evolve in a uniform or fully concordant manner across patients, which may explain why previous studies have reached divergent conclusions regarding the efficacy of conservative treatment. In other words, relying solely on the presence or progression of femoral head collapse as a criterion for therapeutic failure may underestimate the genuine functional benefit achieved in some patients[17,18].

Existing systematic reviews and meta-analyses further indicate that the evidence supporting hip-preserving treatment for ONFH remains uncertain. A network meta-analysis of nine randomized controlled trials found no significant differences between various core decompression techniques and non-surgical treatment in terms of collapse progression or conversion to arthroplasty[19]. This finding does not imply that all hip-preserving interventions are without value; rather, it suggests that whether existing interventions can meaningfully alter the natural course of ONFH may depend substantially on disease stage, extent of necrosis, lesion location, and timing of intervention[20-22]. The size and location of the necrotic lesion may be key determinants of collapse risk. Previous evidence suggests that smaller lesions, particularly those without substantial involvement of the lateral weight-bearing region, may remain stable for prolonged periods even in the absence of aggressive surgical intervention, whereas lesions extensively involving the weight-bearing area are more prone to collapse and progression[6]. Therefore, treatment selection in ONFH should not be guided merely by the presence of radiographic abnormalities, but should instead focus on lesion extent, involvement of the lateral column or weight-bearing region, degree of collapse, symptom burden, and functional status.

From a clinical practice perspective, conservative treatment is not appropriate for all stages of ONFH. In patients with definite structural collapse, secondary degenerative changes, or extensive necrotic involvement of the lateral weight-bearing region, conservative treatment is generally unlikely to serve as a primary therapeutic strategy. If symptoms continue to worsen despite standardized protected weight-bearing, activity modification, and structured follow-up, or if patients are unable to adhere effectively to weight-bearing restrictions, the need for surgical intervention should be reassessed promptly. Conversely, in patients with early-stage disease, no collapse or only mild collapse, limited lesion extent, and manageable symptoms, conservative treatment may remain a reasonable staged hip-preserving option (Figure 1).

Figure 1 Suggested framework for conservative treatment selection in osteonecrosis of the femoral head. Patients with osteonecrosis of the femoral head should be evaluated according to disease stage, lesion extent, lateral weight-bearing involvement, degree of collapse, symptoms, hip function, and compliance with protected weight-bearing and follow-up. Patients with early-stage disease, limited lesion extent, minimal collapse, controllable symptoms, and preserved hip function may be considered suitable for conservative hip-preserving management. In contrast, patients with definite structural collapse, extensive lesion involvement, progressive symptoms, secondary osteoarthritic changes, or poor compliance are generally not favorable candidates for conservative treatment alone and should be reassessed for surgical intervention. ONFH: Osteonecrosis of the femoral head.

CURRENT LIMITATIONS AND FUTURE DIRECTIONS

Although the study by Chen et al[11] provides valuable evidence for reappraising the clinical value of conservative treatment in ONFH, current research on conservative management and non-surgical hip-preserving strategies remains subject to important limitations. First, the non-surgical interventions used across studies vary considerably, including protected weight-bearing, activity modification, pharmacological therapy, physical therapy, structured functional training, and follow-up management[23]. These interventions are not standardized in terms of intensity, duration, implementation criteria, or compliance assessment, making direct comparisons across studies difficult and limiting interpretation of the true efficacy of conservative treatment. Insufficient patient stratification remains another major limitation. The natural course of ONFH is influenced by multiple factors, including disease stage, extent of necrosis, lesion location, degree of collapse, etiology, age, activity level, and treatment adherence[24,25]. Without adequate stratification, patients who are suitable for conservative treatment may be analyzed together with those who are unlikely to benefit, thereby obscuring the true therapeutic effect. Future studies should further establish risk-stratification systems based on imaging characteristics and clinical factors to clarify which patients can achieve long-term functional preservation with conservative treatment and which patients require earlier surgical intervention[26,27].

Beyond simple weight-bearing restriction and activity management, combined hip-preserving strategies also warrant attention. Several studies suggest that traditional Chinese medicine may delay disease progression and reduce the risk of surgical conversion in glucocorticoid-associated ONFH[28-30]. Meta-analyses have further indicated that core decompression combined with cell therapy, extracorporeal shock wave therapy, and other hip-preserving approaches may confer advantages in functional improvement or reduction of treatment failure[31]. However, the quality of evidence, target populations, durability of efficacy, and standardization of protocols for these interventions remain to be further clarified[10,32].

CONCLUSION

Overall, treatment decisions for ONFH should be based on a precise assessment of lesion characteristics and individual patient differences, rather than relying solely on imaging collapse as a single indicator. In patients with limited lesion extent and manageable collapse, standardized conservative treatment is not passive waiting, but rather an effective strategy for long-term functional maintenance in a significant proportion of cases. However, the quality of evidence and consistency of efficacy for various non-surgical methods remain limited, and clinical selection needs to place greater emphasis on stratified management and individualized judgment. Future studies based on rigorously designed, stratified clinical cohorts are needed to clarify which patients truly benefit from conservative treatment.