A case report of pigmented villous nodular synovitis accelerating the progression of femoral head necrosis

A case report of pigmented villous nodular synovitis accelerating the progression of femoral head necrosis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report A case report of pigmented villous nodular synovitis accelerating the progression of femoral head necrosis Wei Yan, Ke Cai, Bin Wang, Zhizhou Wang, Leqin Lin, Haina Jiang, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8625506/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Avascular necrosis of the femoral head (ONFH) is a debilitating condition in which disruption of the femoral head’s blood supply results in collapse of the articular surface and rapid joint destruction. When osteolysis progresses over weeks or months—sometimes termed rapidly progressive osteonecrosis of the femoral head (R‑ONFH) or rapidly destructive hip disease—the pathogenesis is poorly understood. Pigmented villonodular synovitis (PVNS) is a benign but locally aggressive synovial tumour characterised by villous hyperplasia, hemosiderin deposition and abundant macrophages. However, in certain cases—particularly in the context of R-ONFH—this may accelerate the progression of avascular necrosis of the femoral head.PVNS can erode bone and produce inflammatory mediators, yet its role in R‑ONFH has not been defined. Case presentation: We report a case of bilateral ONFH initially diagnosed as idiopathic stage IV disease on the right and stage I disease on the left. Pre‑operative assessment combined anteroposterior and lateral radiographs with axial and coronal computed tomography to stage the necrosis. The patient underwent total hip arthroplasty (THA) via a posterolateral approach. Intra‑operatively, villonodular synovial proliferation, joint effusion and destruction of the femoral head were observed. All abnormal tissue was excised and sent for histology. Post‑operative radiographs assessed prosthetic position and early outcome. Conclusion This case illustrates that PVNS may not simply coexist with ONFH but can accelerate femoral head necrosis through inflammatory, mechanical and enzymatic mechanisms. Pro‑inflammatory cytokines such as tumour necrosis factor‑α, interleukin‑1β and interleukin‑6 can stimulate fibroblast‑like synoviocytes to secrete matrix metalloproteinases, activate osteoclasts and suppress osteoblasts. Villous synovium may mechanically compress the medial and lateral femoral circumflex arteries and directly erode subchondral bone. Recognising PVNS as a potential driver of R‑ONFH is crucial because misdiagnosis as idiopathic necrosis could lead to insufficient treatment; early magnetic resonance imaging (MRI) and complete synovectomy combined with THA or head‑preserving procedures should be considered. Future studies should systematically evaluate the prevalence of PVNS in R‑ONFH and explore targeted anti‑inflammatory therapies. Pigmented Villonodular Synovitis Rapidly Progressive Osteonecrosis of the Femoral Head Avascular Necrosis Synovectomy Total Hip Arthroplasty Figures Figure 1 Figure 2 Figure 3 1. Background Avascular necrosis of the femoral head represents a common cause of hip disability in younger adults and arises when blood supply to the subchondral bone is compromised [ 1 – 3 ] . The resulting imbalance between bone resorption and formation leads to collapse of the femoral head and degenerative arthritis [ 1 – 3 ] . Numerous risk factors are recognised; a comprehensive update reported that chronic corticosteroid therapy, alcohol misuse, trauma and systemic diseases such as sickle‑cell anaemia account for up to 90% of cases [ 1 , 2 ] . Pathogenesis centres on vascular compromise; the femoral head is supplied mainly by the medial and lateral femoral circumflex arteries, with limited collateral circulation [ 3 ] . Emboli, fat microemboli, intravascular coagulation or vasculitis can occlude these vessels, leading to osteocyte death and impaired repair [ 2 , 3 ] . Staging systems such as the Ficat and Arlet classification (stages I–IV) and the Association Research Circulation Osseous (ARCO) system correlate radiographic features with disease severity [ 1 , 2 ] . In early stages conservative therapy or core decompression may preserve the joint, whereas late‑stage disease typically requires total hip arthroplasty (THA) [ 1 , 2 ] . In some patients the joint collapses rapidly, with destruction of the femoral head and acetabulum within months—a presentation termed rapidly progressive osteonecrosis of the femoral head or rapidly destructive hip disease [ 4 ] . This entity is characterised by severe pain, rapid radiographic progression and histologic evidence of osteolysis without osteophyte formation. Its pathogenesis remains uncertain; proposed mechanisms include osteoporosis, crystal arthropathy, subchondral insufficiency fractures and inflammatory synovitis [ 4 ] . A systematic review of rapidly destructive arthrosis reported that all patients demonstrated hip effusion and synovitis on MRI; histology showed multinucleated giant cells and tartrate‑resistant acid phosphatase–positive osteoclasts infiltrating the synovium. These observations suggest that an aggressive inflammatory environment may drive rapid bone resorption [ 5 ] . Pigmented villonodular synovitis—also known as diffuse tenosynovial giant‑cell tumour—is a rare, benign but locally aggressive neoplasm of the synovium [ 6 , 7 ] . PVNS usually affects large joints, particularly the knee and hip [ 6 , 7 ] . It is characterised by villous and nodular hypertrophy of the synovial membrane and deposition of hemosiderin, which imparts a brown colour [ 7 ] . Fibroblast‑like synoviocytes and macrophages dominate the lesion and overexpress pro‑inflammatory cytokines such as tumour necrosis factor‑α, interleukin‑6 and interleukin‑1β, leading to a “cytokine storm”; these mediators stimulate osteoclastogenesis and suppress osteoblast function [ 6 ] . The synovium also secretes matrix metalloproteinases that degrade cartilage and bone matrix, facilitating invasion and erosion [ 5 , 6 ] . On MRI, PVNS appears as heterogeneous synovial thickening with intermediate to low signal intensity on T1‑weighted sequences and low signal on T2‑weighted sequences because of hemosiderin deposition. Diffuse PVNS can lead to secondary osteoarthritis and occasionally to subchondral collapse [ 7 ] . Although PVNS is recognised as a cause of chronic pain and joint destruction, its relationship with ONFH remains unclear [ 6 , 7 ] . Most reported cases of PVNS in the hip describe local bone erosion rather than global head collapse [ 7 ] . A notable case report described massive PVNS around the femoral neck that eroded bone adjacent to the medial and lateral femoral circumflex arteries, likely compromising blood supply and precipitating osteonecrosis [ 8 ] . Such observations raise the possibility that PVNS may not simply be a coincidental finding but may drive R‑ONFH through mechanical compression, inflammatory mediators and enzymatic degradation [ 5 , 6 , 8 ] .However, the mechanism of this effect is not fully understood.This article will explore the potential mechanism of this mechanism [ 6 , 7 ] .Conversely, ischemic bone necrosis may create a pro‑inflammatory environment that promotes synovial proliferation [ 5 , 6 ] . Distinguishing primary PVNS‑driven destruction from secondary synovitis is clinically important because misdiagnosis as idiopathic ONFH could lead to inappropriate treatments—for example, core decompression without synovectomy—which may fail if the inflammatory nidus persists [ 1 , 7 ] . Here we present a case of bilateral ONFH that exemplifies the interplay between PVNS and rapidly progressive necrosis [ 7 , 8 ] . We integrated multimodal radiographic and computed tomography (CT) imaging with intra‑operative assessment and histopathology to characterise the lesion [ 7 , 8 ] . By reviewing relevant literature we propose mechanisms by which PVNS may accelerate necrosis and highlight the diagnostic value of early MRI. This report aims to emphasise the importance of considering PVNS in the differential diagnosis of R‑ONFH and to provide a framework for peri‑operative evaluation and management [ 1 , 7 ] . 2. Case presentation The patient was a middle‑aged adult who presented with a four‑month history of progressively worsening right hip pain radiating to the groin and thigh, accompanied by limited range of motion. There was no history of trauma, corticosteroid use or systemic diseases, but the patient reported a history of alcohol consumption (200ml per day for over 30 years). Physical examination revealed an antalgic gait and decreased internal rotation of the right hip; neurological and vascular examinations were unremarkable.Anteroposterior and frog‑leg radiographs demonstrated collapse of the right femoral head with joint‑space narrowing, consistent with Ficat stage IV ONFH (Figs. 1A,B), while the left femoral head showed only mild sclerosis (stage I). Axial and coronal CT scans corroborated these findings and additionally revealed irregular bone erosions around the femoral neck (Figs. 1C,D).To exclude systemic rheumatic diseases, the patient underwent a comprehensive physical examination with focused assessment of major weight-bearing joints to ensure no underlying pathologies. Concurrently, serological tests for rheumatic disease markers—including rheumatoid factor and antinuclear antibodies—were performed. The final results were normal, with no abnormalities or positive indicators detected. Because of persistent pain and advanced radiographic collapse, the patient elected to undergo total hip arthroplasty of the right hip. A posterolateral approach was used. Intra‑operatively, a large quantity of brownish, villous synovial tissue filled the joint cavity (Figs. 2A,B). The femoral head was deformed, with areas of necrotic bone exposed; the acetabular cartilage was intact. Synovectomy was performed, and the femoral head and neck were removed. A cementless acetabular component and tapered femoral stem were implanted; the remaining synovium was meticulously excised to minimise recurrence (Figs. 2C).Gross examination of the excised tissues showed villonodular synovial proliferation with hemosiderin deposition. The excised hyperplastic synovial tissue was fixed in formalin, embedded in paraffin, and sectioned. After routine hematoxylin-eosin staining, it was evaluated by a senior orthopedic pathologist for histopathological assessment.Histopathology revealed chronic inflammatory cell infiltration, necrotic trabeculae with empty lacunae, fibrous stroma, hemosiderin‑laden macrophages and multinucleated giant cells—findings consistent with diffuse PVNS (Figs. 2D,E). Post‑operative recovery was uncomplicated; radiographs at six weeks demonstrated a well‑positioned, stable prosthesis (Figs. 3A,B). The patient’s pain improved markedly, and hip function scores increased. Because the contralateral hip remained symptomatic but without collapse, conservative management with protected weight bearing and serial imaging was instituted; it showed no rapid progression over the next six months.No complications occurred, and the patient recovered well. No abnormalities were found in the last follow-up (13 months after operation). 3. Discussion In this case we demonstrate that a comprehensive peri‑operative evaluation combining radiographs, CT, surgical inspection and histopathology enables accurate diagnosis and effective management of late‑stage ONFH complicated by PVNS [ 9 , 10 ] . The main conclusion is that PVNS can act as a driving factor for rapidly progressive osteonecrosis rather than a passive bystander; recognising its presence before surgery allows tailored treatment, including synovectomy in addition to THA [ 9 , 11 ] . Below we discuss how our findings address the broader question of what causes R‑ONFH and how they align or conflict with existing literature, identify the limitations of our study and suggest future directions. Pre‑operative imaging provided the first clue that this case differed from typical idiopathic ONFH [ 12 , 13 ] . Radiographs and CT revealed asymmetric disease, with advanced collapse on the right and only mild involvement on the left. Such asymmetry is often seen in R‑ONFH, where destruction may proceed rapidly in one hip while sparing the other [ 14 ] . The Ficat system categorises ONFH based on radiographic stages, but CT affords superior spatial resolution and can detect subtle cortical erosions [ 15 ] . In our patient, CT showed irregular erosions at the head–neck junction that hinted at another pathological process. This observation aligns with a case report of PVNS in which bone erosion encircled the femoral neck and jeopardised the medial and lateral circumflex arteries [ 8 ] . By contrast, idiopathic ONFH usually manifests as subchondral collapse without circumferential erosions [ 13 ] . These imaging findings illustrate how cross‑sectional modalities can raise suspicion for synovial disorders and underscore the need for MRI in the workup of rapid hip destruction. MRI is sensitive for PVNS, demonstrating heterogeneous villous synovial thickening and low signal intensity on T2‑weighted sequences due to hemosiderin [ 13 ] . Had MRI been performed pre‑operatively, PVNS might have been diagnosed earlier and less invasive interventions, such as arthroscopic synovectomy or targeted biological therapy, considered. Recognising PVNS as a potential driver of R‑ONFH carries important diagnostic and therapeutic implications. Clinically, patients with rapid hip destruction and joint effusion should undergo MRI to evaluate for synovial disorders, including PVNS [ 13 , 16 ] . Failure to identify PVNS can result in inappropriate management; for instance, core decompression or bone grafting without synovectomy may leave the inflammatory nidus untreated, leading to recurrence or prosthetic loosening [ 17 ] . Conversely, if PVNS is diagnosed early, arthroscopic or open synovectomy may halt disease progression [ 18 ] . In advanced cases requiring THA, complete synovectomy at the time of arthroplasty reduces the risk of recurrence and has been associated with favourable outcomes [ 9 , 19 ] . Our patient’s uneventful recovery and stable prosthesis support this approach. Moreover, recognising the inflammatory basis of PVNS opens avenues for targeted therapies. Inhibitors of tumour necrosis factor‑α or receptor activator of nuclear factor κB ligand are established treatments for inflammatory arthropathies and may attenuate osteoclast activity in PVNS. The high levels of cytokines and matrix metalloproteinases identified in PVNS tissue suggest that biologics or small‑molecule inhibitors could complement surgical treatment; however, this hypothesis requires prospective evaluation. The exact etiology of PVNS remains unclear, with several theories proposed to explain its pathogenesis, including inflammatory responses, abnormal immune reactions, genetic susceptibility, and post-traumatic recurrent bleeding [ 6 , 20 – 22 ] . The relationship between ONFH and PVNS has not been thoroughly explored, with existing studies being limited [ 22 , 34 , 35 ] . It remains a matter of debate whether PVNS develops as a consequence of the inflammatory response following ONFH or whether PVNS, by affecting the femoral neck, leads to the damage of the femoral head's nutrient arteries, thereby inducing ischemic necrosis [ 6 , 20 – 22 , 30 – 32 ] . Alternatively, it may be that the direct erosive effects of PVNS on bone contribute to the progression of ONFH [ 30 – 33 ] . This causal relationship remains unresolved [ 6 , 22 ] . In this case, after reviewing the patient's history and imaging findings, the right hip was initially diagnosed as suffering from rapidly progressive ONFH, while the left side, although exhibiting necrosis, demonstrated a slower disease progression on follow-up [ 2 , 34 – 36 ] . These observations suggest that the rapid progression of right-sided femoral head necrosis may be associated with PVNS. According to relevant literature, we hypothesize that the patient likely developed bilateral ischemic femoral head necrosis (alcohol-related) initially, with more pronounced inflammatory responses on the right side [ 34 – 37 ] . The heightened inflammatory response may have stimulated synovial hyperplasia, resulting in PVNS [ 6 , 20 – 22 ] . Alternatively, other mechanisms could have led to the development of PVNS, which, through its diffuse growth around the femoral neck, compressed the medial and lateral circumflex arteries, severely compromising the femoral head's blood supply and accelerating the progression of necrosis [ 22 , 30 – 33 ] . This progressive collapse is further exacerbated by the villonodular synovium, which erodes the necrotic femoral head and surrounding joint capsule [ 30 – 33 ] . The mild involvement of the acetabulum, with no significant damage noted on radiographs or CT, aligns with similar findings reported in the literature [ 22 , 26 ] . PVNS may accelerate femoral head necrosis through a complex mechanism involving pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β [ 6 , 33 ] . These cytokines stimulate fibroblast-like synoviocytes to secrete matrix metalloproteinases, activate osteoclasts, and inhibit osteoblast activity, thereby enhancing bone resorption [ 30 – 33 ] . Moreover, the villous synovium may mechanically compress the femoral arteries and directly erode subchondral bone, which exacerbates the damage [ 22 , 30 – 33 ] . This concept is supported by other case reports, which suggest that PVNS can lead to bone erosion near the femoral head's blood supply arteries, contributing to ischemic necrosis [ 20 – 24 , 30 ] . These findings are consistent with previous reports and are further elaborated in the introduction and discussion sections of this paper [ 6 , 22 , 33 ] . Despite these insights, several limitations restrict the scope of our conclusions. First, this is a single case report; the generalisability of our observations is limited, and we cannot infer causality between PVNS and ONFH [ 2 , 22 , 34 – 36 ] . It remains possible that ischemic necrosis preceded synovitis, with necrotic debris triggering secondary PVNS [ 6 , 22 ] . Large cohort studies are needed to determine the prevalence of PVNS among patients with R‑ONFH and to clarify temporal relationships [ 2 , 22 , 28 , 34 – 36 ] . Second, we did not obtain pre‑operative MRI or angiography. MRI could have allowed earlier diagnosis and more conservative management [ 26 , 27 ] , while CT angiography might have identified vascular compression [ 2 , 22 , 34 – 36 ] . Third, we did not analyse synovial cytokine profiles or genetic alterations that might elucidate pathogenic mechanisms [ 20 – 22 , 33 ] . Finally, our follow‑up duration was limited; long‑term outcomes regarding prosthetic survival and recurrence remain unknown [ 27 – 29 ] . Future work should address these gaps. Prospective multicentre studies should evaluate the frequency of PVNS in R‑ONFH, incorporating MRI, CT angiography and serum biomarkers to identify predictive features [ 2 , 22 , 26 , 33 – 36 ] . Basic research examining the cytokine and protease profiles of PVNS tissue may reveal targets for therapy [ 6 , 30 – 33 ] . Comparative trials are needed to assess whether head‑preserving procedures combined with synovectomy can delay or avoid arthroplasty in younger patients [ 27 – 29 ] . Additionally, exploring targeted anti‑inflammatory or anti‑osteoclast agents may yield non‑surgical options to mitigate bone loss [ 23 – 25 , 30 , 33 ] . Understanding the molecular pathways linking inflammatory synovitis to vascular compromise and bone resorption will ultimately inform personalised management strategies for patients with rapidly destructive hip disease [ 2 , 6 , 22 , 33 – 36 ] . 4. Conclusions This case underscores the importance of a multimodal peri‑operative assessment for late‑stage osteonecrosis of the femoral head [ 2 , 34 ] . Combined radiographs and CT identified asymmetric collapse and subtle erosions suggestive of synovial disease [ 2 ] . Intra‑operative inspection and histopathology revealed diffuse pigmented villonodular synovitis, which produced a pro‑inflammatory and proteolytic microenvironment that likely accelerated femoral head necrosis [ 11 ] . Complete synovectomy combined with total hip arthroplasty resulted in effective pain relief and functional restoration [ 32 ] . Our findings contribute to a growing body of evidence that PVNS may be an important differential diagnosis and potential driver of rapidly progressive osteonecrosis [ 11 ] . The pathologic features of PVNS—including cytokine‑mediated osteoclast activation, mechanical compression of the femoral head blood supply and enzymatic matrix degradation—can conspire to precipitate rapid joint destruction [ 11 ] . Clinicians should therefore maintain a high index of suspicion for PVNS in patients presenting with rapid hip collapse. Early MRI, careful assessment of the synovium and thoughtful surgical planning that includes synovectomy can prevent misdiagnosis and optimise outcomes [ 11 , 32 ] . Future research should delineate the epidemiology of PVNS‑associated R‑ONFH and evaluate targeted anti‑inflammatory therapies [ 28 ] .A deeper understanding of the interplay between synovial pathology and vascular compromise will pave the way for personalised interventions that preserve joint integrity and improve patient quality of life [ 11 , 28 ] . Abbreviations The following abbreviations are used in this manuscript: ONFH necrosis of the femoral head R‑ONFH rapidly progressive osteonecrosis of the femoral head MRI Magnetic resonance imaging ARCO the Association Research Circulation Osseous PVNS Pigmented villonodular synovitis THA Total hip arthroplasty CT computed tomography TNF-α Tumor Necrosis Factor-α IL-1β Interleukin-1 β IL-6 Interleukin-6 Declarations Consent for publication: Written informed consent was obtained from the patient before she was included in this study. This study was conducted according to the guidelines of the Declaration of Helsinki. Ethical review was waived as this study presents a description of a clinical case, with no experimental or non-standardized clinical interventions involved. Additionally, the patient’s data have been fully anonymized and do not include any sensitive information that could lead to their identification. Clinical trial number: not applicable. Data availability statements :Data sharing is not applicable to this article as no datasets were generated or analysed during the current study. Informed Consent Statement: Informed consent for this study was obtained for patient. Availability of data and materials: Data cannot be shared due to no new data were created. Conflicts of Interest: The authors declare no conflicts of interest. Funding: This research received no external funding. Author Contributions: Conceptualization, W.Y.; methodology, H.Y.; validation, L.L. and K.C.; formal analysis, HN.J.; investigation, L.L.; resources, W.Y.; data curation, L.L..; writing—original draft preparation, K.C.; writing—review and editing, HJ.J. and W.Y.; visualization, HN.J.; supervision, HJ.J. All authors have read and agreed to the published version of the manuscript. Acknowledgmen s: The authors thank the providers who cared for the patients. 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Nazal MR, Parsa A, Gibbs JS, Abraham PF, Martin SD. Mid-Term Results of Arthroscopic Synovectomy for Pigmented Villonodular Synovitis of the Hip. Arthroscopy. 2020;36(6):1587–98. 10.1016/j.arthro.2020.01.059 . Epub 2020 Feb 13. PMID: 32061973. Ardeljan AD, Polisetty TS, Palmer JR, Toma JJ, Grewal G, Roche MW. Pigmented Villonodular Synovitis of the Hip in Patients Undergoing Total Hip Arthroplasty: A Retrospective Case-Controlled Analysis. J Arthroplasty. 2021;36(3):1018–22. Epub 2020 Sep 7. PMID: 32978024. Xu C, Guo H, Bell KL, Kuo FC, Chen JY. Pigmented villonodular synovitis does not influence the outcome following cementless total hip arthroplasty using ceramic-on-ceramic articulation: a case-control study with middle-term follow-up. J Orthop Surg Res. 2018;13(1):294. 10.1186/s13018-018-0996-6 . PMID: 30458820; PMCID: PMC6245816. Ota T, Urakawa H, Kozawa E, Ikuta K, Hamada S, Tsukushi S, Shimoyama Y, Ishiguro N, Nishida Y. Expression of colony-stimulating factor 1 is associated with occurrence of osteochondral change in pigmented villonodular synovitis. Tumour Biol. 2015;36(7):5361–7. 10.1007/s13277-015-3197-5 . Epub 2015 Feb 18. PMID: 25854167; PMCID: PMC4516862. Taylor R, Kashima TG, Knowles H, Gibbons CL, Whitwell D, Athanasou NA. Osteoclast formation and function in pigmented villonodular synovitis. J Pathol. 2011;225(1):151–6. 10.1002/path.2937 . Epub 2011 Jun 27. PMID: 21706481. Uchibori M, Nishida Y, Tabata I, Sugiura H, Nakashima H, Yamada Y, Ishiguro N. Expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in pigmented villonodular synovitis suggests their potential role for joint destruction. J Rheumatol. 2004;31(1):110–9. PMID: 14705229. Li T, Xiong Y, Li J, Tang X, Zhong Y, Tang Z, Zhang Q, Luo Y. Mapping and Analysis of Protein and Gene Profile Identification of the Important Role of Transforming Growth Factor Beta in Synovial Invasion in Patients With Pigmented Villonodular Synovitis. Arthritis Rheumatol. 2024;76(11):1679–95. 10.1002/art.42946 . Epub 2024 Aug 29. PMID: 38973550. Petek D, Hannouche D, Suva D. Osteonecrosis of the femoral head: pathophysiology and current concepts of treatment. EFORT Open Rev. 2019;4(3):85–97. 10.1302/2058-5241.4.180036 . PMID: 30993010; PMCID: PMC6440301. Yoon BH, Jones LC, Chen CH, Cheng EY, Cui Q, Drescher W, Fukushima W, Gangji V, Goodman SB, Ha YC, Hernigou P, Hungerford M, Iorio R, Jo WL, Khanduja V, Kim H, Kim SY, Kim TY, Lee HY, Lee MS, Lee YK, Lee YJ, Mont MA, Sakai T, Sugano N, Takao M, Yamamoto T, Koo KH. Etiologic Classification Criteria of ARCO on Femoral Head Osteonecrosis Part 2: Alcohol-Associated Osteonecrosis. J Arthroplasty. 2019;34(1):169–e1741. 10.1016/j.arth.2018.09.006 . Epub 2018 Sep 22. PMID: 30348559. Cui Q, Jo WL, Koo KH, Cheng EY, Drescher W, Goodman SB, Ha YC, Hernigou P, Jones LC, Kim SY, Lee KS, Lee MS, Lee YJ, Mont MA, Sugano N, Taliaferro J, Yamamoto T, Zhao D. ARCO Consensus on the Pathogenesis of Non-traumatic Osteonecrosis of the Femoral Head. J Korean Med Sci. 2021;36(10):e65. 10.3346/jkms.2021.36.e65 . PMID: 33724736; PMCID: PMC7961868. Yoon BH, Kim TY, Shin IS, Lee HY, Lee YJ, Koo KH. Alcohol intake and the risk of osteonecrosis of the femoral head in Japanese populations: a dose-response meta-analysis of case-control studies. Clin Rheumatol. 2017;36(11):2517–24. 10.1007/s10067-017-3740-4 . Epub 2017 Jul 6. PMID: 28685377. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8625506","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":580702895,"identity":"1656e4aa-7766-4593-8159-2a388c230390","order_by":0,"name":"Wei Yan","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Wei","middleName":"","lastName":"Yan","suffix":""},{"id":580702896,"identity":"923c9883-0377-4897-affa-c03948f9924c","order_by":1,"name":"Ke Cai","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Ke","middleName":"","lastName":"Cai","suffix":""},{"id":580702897,"identity":"b60ba3ee-6f2c-4cbe-a798-0eefd09f939c","order_by":2,"name":"Bin Wang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Bin","middleName":"","lastName":"Wang","suffix":""},{"id":580702898,"identity":"97716d2c-c01e-4054-89f3-be46ececf853","order_by":3,"name":"Zhizhou Wang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Zhizhou","middleName":"","lastName":"Wang","suffix":""},{"id":580702899,"identity":"ea6b8062-a8d7-46b3-99a3-c3134dd823b2","order_by":4,"name":"Leqin Lin","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Leqin","middleName":"","lastName":"Lin","suffix":""},{"id":580702900,"identity":"84d44667-80f6-46ae-a838-73d526cd5204","order_by":5,"name":"Haina Jiang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Haina","middleName":"","lastName":"Jiang","suffix":""},{"id":580702901,"identity":"5037f8e6-d20c-4107-bcb9-e84382414e23","order_by":6,"name":"Hong Yu","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Hong","middleName":"","lastName":"Yu","suffix":""},{"id":580702902,"identity":"1d87f137-0640-41a9-9860-41ea353da66d","order_by":7,"name":"Lei li","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Lei","middleName":"","lastName":"li","suffix":""},{"id":580702903,"identity":"c1b9d848-511f-4867-9341-90d53cedd38e","order_by":8,"name":"Hongjiang Jiang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAArklEQVRIiWNgGAWjYBACxhkMaSBajo29/QBpWoz5eM4kEGmNBAMbiEqcJ+FgQJwO5tkNzx583GGT3ibBkMDwo2IbEQ6bcyDdcOaZtNw26cYDjD1nbhOhZUZCmjRv2+HcNpkDCcyMbcRr+Z/OJpFgQJKWAwkkaQH6pS3ZsA0YyAeJ8ovhjJy0Bx/b7OTl29sPPvhRQYyWBp4EOOcAYfVAIM/ATpzCUTAKRsEoGMEAAPIOPHFtEMmcAAAAAElFTkSuQmCC","orcid":"","institution":"","correspondingAuthor":true,"prefix":"","firstName":"Hongjiang","middleName":"","lastName":"Jiang","suffix":""}],"badges":[],"createdAt":"2026-01-17 11:08:42","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8625506/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8625506/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101274436,"identity":"4ff789b3-deb9-46b6-8fdb-1ba39878d92b","added_by":"auto","created_at":"2026-01-28 03:10:26","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":841249,"visible":true,"origin":"","legend":"\u003cp\u003eA) Anteroposterior radiograph before surgery, showing necrosis of the right femoral head with nearly complete loss of its shape, and less severe necrosis of the left femoral head.\u003c/p\u003e\n\u003cp\u003eB) Lateral radiograph before surgery, showing necrosis of the right femoral head with nearly complete loss of its shape, and less severe necrosis of the left femoral head.\u003c/p\u003e\n\u003cp\u003eC) Axial CT scan, showing collapse and extensive destruction of the right femoral head, mild involvement of the acetabulum, and significant joint effusion.\u003c/p\u003e\n\u003cp\u003eD) Coronal CT scan, showing collapse and extensive destruction of the right femoral head, mild involvement of the acetabulum, and significant joint effusion, with microfractures of the subchondral bone of the left femoral head, and collapse of less than 2mm.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8625506/v1/48bf603f598d58b0455cba39.png"},{"id":101274485,"identity":"2aa3eeb6-91e0-4c21-95ae-dc4405d28e7d","added_by":"auto","created_at":"2026-01-28 03:10:43","extension":"jpeg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":2129483,"visible":true,"origin":"","legend":"\u003cp\u003eA) Anteroposterior radiograph after femoral head dislocation, showing extensive villonodular synovial proliferation enveloping the head-neck region of the right femoral head, with nearly complete loss of its shape.\u003c/p\u003e\n\u003cp\u003eB) Lateral radiograph, showing villonodular synovial proliferation within the joint capsule and around the acetabulum.\u003c/p\u003e\n\u003cp\u003eC) Extracted femoral head-neck region and partially cleaned synovial tissue showing the diseased tissue.\u003c/p\u003e\n\u003cp\u003eD) Histopathological slide of synovial tissue, HE staining (x40), showing mononuclear stromal cells, a few lymphocytes, and scattered multinucleated giant cells, with hemosiderin (brownish) deposition.\u003c/p\u003e\n\u003cp\u003eE) Post-decalcification HE staining of the femoral head tissue removed during surgery (x40), showing trabecular degeneration, necrosis, fractures, fibrous tissue proliferation in the marrow cavity, and a small amount of lymphocytic proliferation.\u003c/p\u003e","description":"","filename":"floatimage2.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8625506/v1/3d976c0909ea4044713bc797.jpeg"},{"id":101274453,"identity":"f8c975b9-a072-4bdb-a026-16f8b95099d9","added_by":"auto","created_at":"2026-01-28 03:10:32","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":144000,"visible":true,"origin":"","legend":"\u003cp\u003eA) Anteroposterior radiograph after surgery, showing proper position of the prosthesis, securely fixed with no signs of loosening.\u003c/p\u003e\n\u003cp\u003eB) Lateral radiograph after surgery, showing proper position of the prosthesis, securely fixed with no signs of loosening.\u003c/p\u003e","description":"","filename":"floatimage3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-8625506/v1/3a4215ad6ad9e5646ec69fb8.jpeg"},{"id":103505625,"identity":"987757b3-4b4e-4e4e-8556-8828e9941573","added_by":"auto","created_at":"2026-02-26 13:32:14","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3718942,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8625506/v1/ba0292a6-bb47-4ac6-a8f1-5634d07fab98.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"A case report of pigmented villous nodular synovitis accelerating the progression of femoral head necrosis","fulltext":[{"header":"1. Background","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eAvascular necrosis of the femoral head represents a common cause of hip disability in younger adults and arises when blood supply to the subchondral bone is compromised\u003csup\u003e[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. The resulting imbalance between bone resorption and formation leads to collapse of the femoral head and degenerative arthritis\u003csup\u003e[\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. Numerous risk factors are recognised; a comprehensive update reported that chronic corticosteroid therapy, alcohol misuse, trauma and systemic diseases such as sickle‑cell anaemia account for up to 90% of cases\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Pathogenesis centres on vascular compromise; the femoral head is supplied mainly by the medial and lateral femoral circumflex arteries, with limited collateral circulation\u003csup\u003e[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. Emboli, fat microemboli, intravascular coagulation or vasculitis can occlude these vessels, leading to osteocyte death and impaired repair\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]\u003c/sup\u003e. Staging systems such as the Ficat and Arlet classification (stages I\u0026ndash;IV) and the Association Research Circulation Osseous (ARCO) system correlate radiographic features with disease severity\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. In early stages conservative therapy or core decompression may preserve the joint, whereas late‑stage disease typically requires total hip arthroplasty (THA)\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eIn some patients the joint collapses rapidly, with destruction of the femoral head and acetabulum within months\u0026mdash;a presentation termed rapidly progressive osteonecrosis of the femoral head or rapidly destructive hip disease\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. This entity is characterised by severe pain, rapid radiographic progression and histologic evidence of osteolysis without osteophyte formation. Its pathogenesis remains uncertain; proposed mechanisms include osteoporosis, crystal arthropathy, subchondral insufficiency fractures and inflammatory synovitis\u003csup\u003e[\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/sup\u003e. A systematic review of rapidly destructive arthrosis reported that all patients demonstrated hip effusion and synovitis on MRI; histology showed multinucleated giant cells and tartrate‑resistant acid phosphatase\u0026ndash;positive osteoclasts infiltrating the synovium. These observations suggest that an aggressive inflammatory environment may drive rapid bone resorption\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePigmented villonodular synovitis\u0026mdash;also known as diffuse tenosynovial giant‑cell tumour\u0026mdash;is a rare, benign but locally aggressive neoplasm of the synovium\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. PVNS usually affects large joints, particularly the knee and hip\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. It is characterised by villous and nodular hypertrophy of the synovial membrane and deposition of hemosiderin, which imparts a brown colour\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Fibroblast‑like synoviocytes and macrophages dominate the lesion and overexpress pro‑inflammatory cytokines such as tumour necrosis factor‑α, interleukin‑6 and interleukin‑1β, leading to a \u0026ldquo;cytokine storm\u0026rdquo;; these mediators stimulate osteoclastogenesis and suppress osteoblast function\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. The synovium also secretes matrix metalloproteinases that degrade cartilage and bone matrix, facilitating invasion and erosion\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. On MRI, PVNS appears as heterogeneous synovial thickening with intermediate to low signal intensity on T1‑weighted sequences and low signal on T2‑weighted sequences because of hemosiderin deposition. Diffuse PVNS can lead to secondary osteoarthritis and occasionally to subchondral collapse\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eAlthough PVNS is recognised as a cause of chronic pain and joint destruction, its relationship with ONFH remains unclear\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. Most reported cases of PVNS in the hip describe local bone erosion rather than global head collapse\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e. A notable case report described massive PVNS around the femoral neck that eroded bone adjacent to the medial and lateral femoral circumflex arteries, likely compromising blood supply and precipitating osteonecrosis\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. Such observations raise the possibility that PVNS may not simply be a coincidental finding but may drive R‑ONFH through mechanical compression, inflammatory mediators and enzymatic degradation\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e.However, the mechanism of this effect is not fully understood.This article will explore the potential mechanism of this mechanism\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e.Conversely, ischemic bone necrosis may create a pro‑inflammatory environment that promotes synovial proliferation\u003csup\u003e[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/sup\u003e. Distinguishing primary PVNS‑driven destruction from secondary synovitis is clinically important because misdiagnosis as idiopathic ONFH could lead to inappropriate treatments\u0026mdash;for example, core decompression without synovectomy\u0026mdash;which may fail if the inflammatory nidus persists\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eHere we present a case of bilateral ONFH that exemplifies the interplay between PVNS and rapidly progressive necrosis\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. We integrated multimodal radiographic and computed tomography (CT) imaging with intra‑operative assessment and histopathology to characterise the lesion\u003csup\u003e[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. By reviewing relevant literature we propose mechanisms by which PVNS may accelerate necrosis and highlight the diagnostic value of early MRI. This report aims to emphasise the importance of considering PVNS in the differential diagnosis of R‑ONFH and to provide a framework for peri‑operative evaluation and management\u003csup\u003e[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"2. Case presentation","content":"\u003cdiv\u003e\n\u003cp\u003eThe patient was a middle‑aged adult who presented with a four‑month history of progressively worsening right hip pain radiating to the groin and thigh, accompanied by limited range of motion. There was no history of trauma, corticosteroid use or systemic diseases, but the patient reported a history of alcohol consumption (200ml per day for over 30 years). Physical examination revealed an antalgic gait and decreased internal rotation of the right hip; neurological and vascular examinations were unremarkable.Anteroposterior and frog‑leg radiographs demonstrated collapse of the right femoral head with joint‑space narrowing, consistent with Ficat stage IV ONFH (Figs.\u0026nbsp;1A,B), while the left femoral head showed only mild sclerosis (stage I). Axial and coronal CT scans corroborated these findings and additionally revealed irregular bone erosions around the femoral neck (Figs.\u0026nbsp;1C,D).To exclude systemic rheumatic diseases, the patient underwent a comprehensive physical examination with focused assessment of major weight-bearing joints to ensure no underlying pathologies. Concurrently, serological tests for rheumatic disease markers\u0026mdash;including rheumatoid factor and antinuclear antibodies\u0026mdash;were performed. The final results were normal, with no abnormalities or positive indicators detected.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv\u003e\n\u003cp\u003eBecause of persistent pain and advanced radiographic collapse, the patient elected to undergo total hip arthroplasty of the right hip. A posterolateral approach was used. Intra‑operatively, a large quantity of brownish, villous synovial tissue filled the joint cavity (Figs.\u0026nbsp;2A,B). The femoral head was deformed, with areas of necrotic bone exposed; the acetabular cartilage was intact. Synovectomy was performed, and the femoral head and neck were removed. A cementless acetabular component and tapered femoral stem were implanted; the remaining synovium was meticulously excised to minimise recurrence (Figs.\u0026nbsp;2C).Gross examination of the excised tissues showed villonodular synovial proliferation with hemosiderin deposition. The excised hyperplastic synovial tissue was fixed in formalin, embedded in paraffin, and sectioned. After routine hematoxylin-eosin staining, it was evaluated by a senior orthopedic pathologist for histopathological assessment.Histopathology revealed chronic inflammatory cell infiltration, necrotic trabeculae with empty lacunae, fibrous stroma, hemosiderin‑laden macrophages and multinucleated giant cells\u0026mdash;findings consistent with diffuse PVNS (Figs.\u0026nbsp;2D,E).\u003c/p\u003e\n\u003c/div\u003e\n\u003cp\u003ePost‑operative recovery was uncomplicated; radiographs at six weeks demonstrated a well‑positioned, stable prosthesis (Figs.\u0026nbsp;3A,B). The patient\u0026rsquo;s pain improved markedly, and hip function scores increased. Because the contralateral hip remained symptomatic but without collapse, conservative management with protected weight bearing and serial imaging was instituted; it showed no rapid progression over the next six months.No complications occurred, and the patient recovered well. No abnormalities were found in the last follow-up (13 months after operation).\u003c/p\u003e"},{"header":"3. Discussion","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eIn this case we demonstrate that a comprehensive peri‑operative evaluation combining radiographs, CT, surgical inspection and histopathology enables accurate diagnosis and effective management of late‑stage ONFH complicated by PVNS\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]\u003c/sup\u003e. The main conclusion is that PVNS can act as a driving factor for rapidly progressive osteonecrosis rather than a passive bystander; recognising its presence before surgery allows tailored treatment, including synovectomy in addition to THA\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Below we discuss how our findings address the broader question of what causes R‑ONFH and how they align or conflict with existing literature, identify the limitations of our study and suggest future directions.\u003c/p\u003e \u003cp\u003ePre‑operative imaging provided the first clue that this case differed from typical idiopathic ONFH\u003csup\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. Radiographs and CT revealed asymmetric disease, with advanced collapse on the right and only mild involvement on the left. Such asymmetry is often seen in R‑ONFH, where destruction may proceed rapidly in one hip while sparing the other\u003csup\u003e[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]\u003c/sup\u003e. The Ficat system categorises ONFH based on radiographic stages, but CT affords superior spatial resolution and can detect subtle cortical erosions\u003csup\u003e[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/sup\u003e. In our patient, CT showed irregular erosions at the head\u0026ndash;neck junction that hinted at another pathological process. This observation aligns with a case report of PVNS in which bone erosion encircled the femoral neck and jeopardised the medial and lateral circumflex arteries\u003csup\u003e[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]\u003c/sup\u003e. By contrast, idiopathic ONFH usually manifests as subchondral collapse without circumferential erosions\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. These imaging findings illustrate how cross‑sectional modalities can raise suspicion for synovial disorders and underscore the need for MRI in the workup of rapid hip destruction. MRI is sensitive for PVNS, demonstrating heterogeneous villous synovial thickening and low signal intensity on T2‑weighted sequences due to hemosiderin\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]\u003c/sup\u003e. Had MRI been performed pre‑operatively, PVNS might have been diagnosed earlier and less invasive interventions, such as arthroscopic synovectomy or targeted biological therapy, considered.\u003c/p\u003e \u003cp\u003eRecognising PVNS as a potential driver of R‑ONFH carries important diagnostic and therapeutic implications. Clinically, patients with rapid hip destruction and joint effusion should undergo MRI to evaluate for synovial disorders, including PVNS\u003csup\u003e[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]\u003c/sup\u003e. Failure to identify PVNS can result in inappropriate management; for instance, core decompression or bone grafting without synovectomy may leave the inflammatory nidus untreated, leading to recurrence or prosthetic loosening\u003csup\u003e[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]\u003c/sup\u003e. Conversely, if PVNS is diagnosed early, arthroscopic or open synovectomy may halt disease progression\u003csup\u003e[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/sup\u003e. In advanced cases requiring THA, complete synovectomy at the time of arthroplasty reduces the risk of recurrence and has been associated with favourable outcomes\u003csup\u003e[\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/sup\u003e. Our patient\u0026rsquo;s uneventful recovery and stable prosthesis support this approach. Moreover, recognising the inflammatory basis of PVNS opens avenues for targeted therapies. Inhibitors of tumour necrosis factor‑α or receptor activator of nuclear factor κB ligand are established treatments for inflammatory arthropathies and may attenuate osteoclast activity in PVNS. The high levels of cytokines and matrix metalloproteinases identified in PVNS tissue suggest that biologics or small‑molecule inhibitors could complement surgical treatment; however, this hypothesis requires prospective evaluation.\u003c/p\u003e \u003cp\u003eThe exact etiology of PVNS remains unclear, with several theories proposed to explain its pathogenesis, including inflammatory responses, abnormal immune reactions, genetic susceptibility, and post-traumatic recurrent bleeding\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. The relationship between ONFH and PVNS has not been thoroughly explored, with existing studies being limited\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]\u003c/sup\u003e. It remains a matter of debate whether PVNS develops as a consequence of the inflammatory response following ONFH or whether PVNS, by affecting the femoral neck, leads to the damage of the femoral head's nutrient arteries, thereby inducing ischemic necrosis\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan additionalcitationids=\"CR31\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e. Alternatively, it may be that the direct erosive effects of PVNS on bone contribute to the progression of ONFH\u003csup\u003e[\u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. This causal relationship remains unresolved\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. In this case, after reviewing the patient's history and imaging findings, the right hip was initially diagnosed as suffering from rapidly progressive ONFH, while the left side, although exhibiting necrosis, demonstrated a slower disease progression on follow-up\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan additionalcitationids=\"CR35\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. These observations suggest that the rapid progression of right-sided femoral head necrosis may be associated with PVNS. According to relevant literature, we hypothesize that the patient likely developed bilateral ischemic femoral head necrosis (alcohol-related) initially, with more pronounced inflammatory responses on the right side\u003csup\u003e[\u003cspan additionalcitationids=\"CR35 CR36\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]\u003c/sup\u003e. The heightened inflammatory response may have stimulated synovial hyperplasia, resulting in PVNS\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. Alternatively, other mechanisms could have led to the development of PVNS, which, through its diffuse growth around the femoral neck, compressed the medial and lateral circumflex arteries, severely compromising the femoral head's blood supply and accelerating the progression of necrosis\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. This progressive collapse is further exacerbated by the villonodular synovium, which erodes the necrotic femoral head and surrounding joint capsule\u003csup\u003e[\u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. The mild involvement of the acetabulum, with no significant damage noted on radiographs or CT, aligns with similar findings reported in the literature\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003ePVNS may accelerate femoral head necrosis through a complex mechanism involving pro-inflammatory cytokines such as TNF-α, IL-6, and IL-1β\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. These cytokines stimulate fibroblast-like synoviocytes to secrete matrix metalloproteinases, activate osteoclasts, and inhibit osteoblast activity, thereby enhancing bone resorption\u003csup\u003e[\u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. Moreover, the villous synovium may mechanically compress the femoral arteries and directly erode subchondral bone, which exacerbates the damage\u003csup\u003e[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. This concept is supported by other case reports, which suggest that PVNS can lead to bone erosion near the femoral head's blood supply arteries, contributing to ischemic necrosis\u003csup\u003e[\u003cspan additionalcitationids=\"CR21 CR22 CR23\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e]\u003c/sup\u003e. These findings are consistent with previous reports and are further elaborated in the introduction and discussion sections of this paper\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eDespite these insights, several limitations restrict the scope of our conclusions. First, this is a single case report; the generalisability of our observations is limited, and we cannot infer causality between PVNS and ONFH\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan additionalcitationids=\"CR35\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. It remains possible that ischemic necrosis preceded synovitis, with necrotic debris triggering secondary PVNS\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]\u003c/sup\u003e. Large cohort studies are needed to determine the prevalence of PVNS among patients with R‑ONFH and to clarify temporal relationships\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan additionalcitationids=\"CR35\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. Second, we did not obtain pre‑operative MRI or angiography. MRI could have allowed earlier diagnosis and more conservative management\u003csup\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]\u003c/sup\u003e, while CT angiography might have identified vascular compression\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan additionalcitationids=\"CR35\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. Third, we did not analyse synovial cytokine profiles or genetic alterations that might elucidate pathogenic mechanisms\u003csup\u003e[\u003cspan additionalcitationids=\"CR21\" citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. Finally, our follow‑up duration was limited; long‑term outcomes regarding prosthetic survival and recurrence remain unknown\u003csup\u003e[\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eFuture work should address these gaps. Prospective multicentre studies should evaluate the frequency of PVNS in R‑ONFH, incorporating MRI, CT angiography and serum biomarkers to identify predictive features\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e, \u003cspan additionalcitationids=\"CR34 CR35\" citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e. Basic research examining the cytokine and protease profiles of PVNS tissue may reveal targets for therapy\u003csup\u003e[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. Comparative trials are needed to assess whether head‑preserving procedures combined with synovectomy can delay or avoid arthroplasty in younger patients\u003csup\u003e[\u003cspan additionalcitationids=\"CR28\" citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]\u003c/sup\u003e. Additionally, exploring targeted anti‑inflammatory or anti‑osteoclast agents may yield non‑surgical options to mitigate bone loss\u003csup\u003e[\u003cspan additionalcitationids=\"CR24\" citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/sup\u003e. Understanding the molecular pathways linking inflammatory synovitis to vascular compromise and bone resorption will ultimately inform personalised management strategies for patients with rapidly destructive hip disease\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e, \u003cspan additionalcitationids=\"CR34 CR35\" citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThis case underscores the importance of a multimodal peri‑operative assessment for late‑stage osteonecrosis of the femoral head\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e]\u003c/sup\u003e. Combined radiographs and CT identified asymmetric collapse and subtle erosions suggestive of synovial disease\u003csup\u003e[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]\u003c/sup\u003e. Intra‑operative inspection and histopathology revealed diffuse pigmented villonodular synovitis, which produced a pro‑inflammatory and proteolytic microenvironment that likely accelerated femoral head necrosis\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Complete synovectomy combined with total hip arthroplasty resulted in effective pain relief and functional restoration\u003csup\u003e[\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eOur findings contribute to a growing body of evidence that PVNS may be an important differential diagnosis and potential driver of rapidly progressive osteonecrosis\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. The pathologic features of PVNS\u0026mdash;including cytokine‑mediated osteoclast activation, mechanical compression of the femoral head blood supply and enzymatic matrix degradation\u0026mdash;can conspire to precipitate rapid joint destruction\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/sup\u003e. Clinicians should therefore maintain a high index of suspicion for PVNS in patients presenting with rapid hip collapse. Early MRI, careful assessment of the synovium and thoughtful surgical planning that includes synovectomy can prevent misdiagnosis and optimise outcomes\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e]\u003c/sup\u003e. Future research should delineate the epidemiology of PVNS‑associated R‑ONFH and evaluate targeted anti‑inflammatory therapies\u003csup\u003e[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e.A deeper understanding of the interplay between synovial pathology and vascular compromise will pave the way for personalised interventions that preserve joint integrity and improve patient quality of life\u003csup\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eThe following abbreviations are used in this manuscript:\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"542\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eONFH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003enecrosis of the femoral head\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eR‑ONFH\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003erapidly progressive osteonecrosis of the femoral head\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eMRI\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eMagnetic resonance imaging\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eARCO\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ethe Association Research Circulation Osseous\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003ePVNS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ePigmented villonodular synovitis\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eTHA\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eTotal hip arthroplasty\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eCT\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003ecomputed tomography\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eTNF-α\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eTumor Necrosis Factor-α\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eIL-1β\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eInterleukin-1 β\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd\u003e\n \u003cp\u003eIL-6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd\u003e\n \u003cp\u003eInterleukin-6\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConsent for publication:\u003c/strong\u003e Written informed consent was obtained from the patient before she was included in this study. This study was conducted according to the guidelines of the Declaration of Helsinki. Ethical review was waived as this study presents a description of a clinical case, with no experimental or non-standardized clinical interventions involved. Additionally, the patient’s data have been fully anonymized and do not include any sensitive information that could lead to their identification.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eClinical trial number:\u003c/strong\u003e not applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statements\u003c/strong\u003e:Data sharing is not applicable to this article as no datasets were generated or analysed during the current study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInformed Consent Statement:\u0026nbsp;\u003c/strong\u003eInformed consent for this study was obtained for patient.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials:\u003c/strong\u003e Data cannot be shared due to no new data were created.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of Interest:\u003c/strong\u003e The authors declare no conflicts of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e This research received no external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u003c/strong\u003e Conceptualization,\u0026nbsp;W.Y.; methodology, H.Y.; validation, L.L. and K.C.; formal analysis, HN.J.; investigation, L.L.; resources, W.Y.; data curation, L.L..; writing—original draft preparation, K.C.; writing—review and editing, HJ.J.\u0026nbsp;and W.Y.; visualization, HN.J.; supervision, HJ.J. All authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgmen\u003c/strong\u003e\u003cstrong\u003es:\u003c/strong\u003eThe authors thank the providers who cared for the patients.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eZhao D, Zhang F, Wang B, Liu B, Li L, Kim SY, Goodman SB, Hernigou P, Cui Q, Lineaweaver WC, Xu J, Drescher WR, Qin L. Guidelines for clinical diagnosis and treatment of osteonecrosis of the femoral head in adults (2019 version). J Orthop Translat. 2020;21:100\u0026ndash;10. PMID: 32309135; PMCID: PMC7152793.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHines JT, Jo WL, Cui Q, Mont MA, Koo KH, Cheng EY, Goodman SB, Ha YC, Hernigou P, Jones LC, Kim SY, Sakai T, Sugano N, Yamamoto T, Lee MS, Zhao D, Drescher W, Kim TY, Lee YK, Yoon BH, Baek SH, Ando W, Kim HS, Park JW. 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PMID: 28685377.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Pigmented Villonodular Synovitis, Rapidly Progressive Osteonecrosis of the Femoral Head, Avascular Necrosis, Synovectomy, Total Hip Arthroplasty","lastPublishedDoi":"10.21203/rs.3.rs-8625506/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8625506/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e \u003cp\u003eAvascular necrosis of the femoral head (ONFH) is a debilitating condition in which disruption of the femoral head\u0026rsquo;s blood supply results in collapse of the articular surface and rapid joint destruction. When osteolysis progresses over weeks or months\u0026mdash;sometimes termed rapidly progressive osteonecrosis of the femoral head (R‑ONFH) or rapidly destructive hip disease\u0026mdash;the pathogenesis is poorly understood. Pigmented villonodular synovitis (PVNS) is a benign but locally aggressive synovial tumour characterised by villous hyperplasia, hemosiderin deposition and abundant macrophages. However, in certain cases\u0026mdash;particularly in the context of R-ONFH\u0026mdash;this may accelerate the progression of avascular necrosis of the femoral head.PVNS can erode bone and produce inflammatory mediators, yet its role in R‑ONFH has not been defined.\u003c/p\u003e\u003ch2\u003eCase presentation:\u003c/h2\u003e \u003cp\u003eWe report a case of bilateral ONFH initially diagnosed as idiopathic stage IV disease on the right and stage I disease on the left. Pre‑operative assessment combined anteroposterior and lateral radiographs with axial and coronal computed tomography to stage the necrosis. The patient underwent total hip arthroplasty (THA) via a posterolateral approach. Intra‑operatively, villonodular synovial proliferation, joint effusion and destruction of the femoral head were observed. All abnormal tissue was excised and sent for histology. Post‑operative radiographs assessed prosthetic position and early outcome.\u003c/p\u003e\u003ch2\u003eConclusion\u003c/h2\u003e \u003cp\u003eThis case illustrates that PVNS may not simply coexist with ONFH but can accelerate femoral head necrosis through inflammatory, mechanical and enzymatic mechanisms. Pro‑inflammatory cytokines such as tumour necrosis factor‑α, interleukin‑1β and interleukin‑6 can stimulate fibroblast‑like synoviocytes to secrete matrix metalloproteinases, activate osteoclasts and suppress osteoblasts. Villous synovium may mechanically compress the medial and lateral femoral circumflex arteries and directly erode subchondral bone. Recognising PVNS as a potential driver of R‑ONFH is crucial because misdiagnosis as idiopathic necrosis could lead to insufficient treatment; early magnetic resonance imaging (MRI) and complete synovectomy combined with THA or head‑preserving procedures should be considered. Future studies should systematically evaluate the prevalence of PVNS in R‑ONFH and explore targeted anti‑inflammatory therapies.\u003c/p\u003e","manuscriptTitle":"A case report of pigmented villous nodular synovitis accelerating the progression of femoral head necrosis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-28 03:09:25","doi":"10.21203/rs.3.rs-8625506/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"c4e65cde-e181-42ea-9fe8-c530fbf54733","owner":[],"postedDate":"January 28th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-02-23T15:56:23+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-28 03:09:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8625506","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8625506","identity":"rs-8625506","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}