Aetiology of Legg-Calvé-Perthes disease: A systematic review

Bone Remodeling and Bone Structural Genes in Legg-Calvé-Perthes Disease: The OPG rs2073618 and IL-6 rs1800795 Are Associated with High Risk in Mexican Patients

Legg-Calve-Perthes disease (LCPD) is an idiopathic avascular necrosis of the pediatric femoral head. Bone remodeling and bone structural genes have the potential to contribute to the progression of LCPD when there is disequilibrium between bone resorption and bone formation. A case-control study was performed to search for associations of several common polymorphisms in the genes Receptor Activator for Nuclear Factor κappa B (RANK), Receptor Activator for Nuclear Factor κappa B Ligand (RANKL), osteoprotegerin (OPG), interleukin (IL)-6, and type 1 collagen (COL1A1) with LCPD susceptibility in Mexican children. A total of 23 children with LCPD and 46 healthy controls were genotyped for seven polymorphisms (rs3018362, rs12585014, rs2073618, rs1800795, rs1800796, rs1800012, and rs2586498) in the RANK, RANKL, OPG, IL-6, and COL1A1 genes by real-time polymerase chain reaction with TaqMan probes. The variant allele (C) of IL-6 rs1800795 was associated with increased risk of LCPD (odds ratio [OR]: 3.8, 95% confidence interval [CI]: [1.08-13.54], p = 0.033), adjusting data by body mass index (BMI) and coagulation factor V (FV), the association with increased risk remained (OR: 4.9, 95% CI: [1.14-21.04], p = 0.025). The OPG polymorphism rs2073618, specifically GC-GG carriers, was associated with a more than fourfold increased risk of developing LCPD (OR: 4.34, 95% CI: [1.04-18.12], p = 0.033) when data were adjusted by BMI-FV. There was no significant association between RANK rs3018362, RANKL rs12585014, IL-6 rs1800796, COL1A1 rs1800012, and rs2586498 polymorphisms and LCPD in a sample of Mexican children. The rs1800975 and rs2037618 polymorphisms in the IL-6 and OPG genes, respectively, are informative markers of increased risk of LCPD in Mexican children.

Global trends in the research on Legg-Calve-Perthes disease in Web of Science

Background

Legg-Calve-Perthes disease (LCPD) is a form of idiopathic femoral head necrosis that can lead to permanent femoral head deformities and premature osteoarthritis in children under the age of 15. Its pathogenesis is utterly and remains to be clarified. Although many research publications on LCPD have emerged during the last few decades, few systematic bibliometric analyses of these articles have been reported.

Methods

A bibliometric analysis was performed to investigate the development processes and hotspots, as well as the collaboration and influence among countries, institutions, authors, journals, and keywords of papers relevant to LCPD from the Web of Science Core Collection (WoSCC) during the period from 1 January 2000 to 30 June 2023.

Results

A total of 2,205 researchers from 916 institutions across 53 countries/regions have contributed to 673 papers published in 199 academic journals. The research on LCPD has shown significant fluctuations but a gradual increase in the number of articles published over the last two decades. The United States leads in the number of publications of LCPD, with the Texas Scottish Rite Hospital for Children being the most productive institution. English, as the most widely used language in the world, was undoubtedly the most popular language. Herring JA, who acted as both the corresponding and first author, has contributed to the most co-cited papers published. The most number of LCPD papers are published in the Journal of Pediatric Orthopaedics, whereas the Journal of Bone and Joint Surgery American Volume garnered the highest total citations, indicating the great importance of these two journals in the field of orthopedics. The most frequently used keywords in published articles were related to the symptoms, mechanisms, and prognosis, revealing the research focus of most scholars.

Conclusion

Our research described the development trends and hotspots in the research field of LCPD and will help researchers make better decisions.

Legg-Calvé-Perthes Disease: Diagnosis, Decision Making, and Outcome

ABSTRACT

Legg-Calvé-Perthes disease (LCPD), or idiopathic avascular necrosis of the proximal capital femoral epiphysis in children, has a variable presentation and can result in significant femoral head deformity that can lead to long-term functional deficits. Plain radiographic imaging is crucial in diagnosing LCPD and guiding treatment. Although the etiology of LCPD remains unknown, the evolution of the disease has been well characterized to include the phases of ischemia, revascularization, and reossification. The mechanical weakening during these phases of healing place the femoral head at high risk of deformity. Treatment of LCPD, therefore, focuses on minimizing deformity through operative and nonoperative strategies to reduce the risk of premature osteoarthritis. Advanced imaging using perfusion MRI may refine surgical decision making in the future, and biological treatments to improve femoral head healing are on the horizon.

Prediction of the active compounds and mechanism of Biochanin A in the treatment of Legg-Calvé-Perthes disease based on network pharmacology and molecular docking

BACKGROUND

Legg-Calvé-Perthes disease is a special self-limited disease in pediatric orthopedics with a high disability rate and a long-term course, and there is still no clear and effective therapeutic drug in clinic. This study aimed to investigate the potential efficacy of biochanin A, a kind of oxygen-methylated isoflavone compound, in treating Perthes disease based on network pharmacology, molecular docking and in vitro experiments.

METHODS

IL-6 was used to stimulate human umbilical vein endothelial cells to construct endothelial cell dysfunction model. We demonstrated whether biochanin A could alleviate endothelial dysfunction through CCK8 assay, immunofluorescence. Targets of biochanin A from pharmMappeer, SWISS, and TargetNet databases were screened. Targets of endothelial dysfunction were obtained from Genecards and OMIM databases. Protein-protein interaction, Gene Ontology, and Kyoto Encyclopedia of Genes and Genomics analyses were used to analyze the potential target and the key pathway of the anti-endothelial dysfunction activity of biochanin A. To validate the potential target-drug interactions, molecular docking and molecular dynamics simulations were performed and the result was proved by western blot.

RESULTS

It was found that biochanin A can promote the expression of ZO-1, reduce the expression of ICAM-1, which means improving endothelial dysfunction. A total of 585 targets of biochanin A from pharmMappeer, SWISS, and TargetNet databases were screened. A total of 10,832 targets of endothelial dysfunction were obtained from Genecards and OMIM databases. A total of 527 overlapping targets of endothelial dysfunction and biochanin A were obtained. AKT1, TNF-α, VCAM1, ICAM1, and NOS3 might be the key targets of the anti-endothelial dysfunction activity of biochanin A, and the key pathways might be PI3K-Akt and TNF signaling pathways. Molecular docking results indicated that the AKT1 and TNF-α had the highest affinity binding with biochanin A.

CONCLUSION

This study indicates that biochanin A can target AKT1 and TNF-α to alleviate endothelial dysfunction induced by IL-6 in Perthes disease, which provides a theoretical basis for the treatment of Perthes disease by using biochanin A.

Legg-Calve-Perthes' disease: an opportunity to prevent blindness?

Legg-Calve-Perthes' disease (LCP) is defined as avascular necrosis of the femoral head in a child and may present to a variety of disciplines from general practice to orthopaedics, paediatrics, rheumatology and more. The Stickler syndromes are a group of disorders of type II, IX and XI collagen associated with hip dysplasia, retinal detachment, deafness and cleft palate. The pathogenesis of LCP disease remains an enigma but there have been a small number of cases reporting variants in the gene encoding the α1 chain of type II collagen (COL2A1). Variants in COL2A1 are known to cause type 1 Stickler syndrome (MIM 108300, 609508), which is a connective tissue disorder with a very high risk of childhood blindness, and it is also associated with dysplastic development of the femoral head. It is unclear whether COL2A1 variants make a definitive contribution to both disorders, or whether the two are indistinguishable using current clinical diagnostic techniques. In this paper, we compare the two conditions and present a case series of 19 patients with genetically confirmed type 1 Stickler syndrome presenting with a historic diagnosis of LCP. In contrast to isolated LCP, children with type 1 Stickler syndrome have a very high risk of blindness from giant retinal tear detachment, but this is now largely preventable if a timely diagnosis is made. This paper highlights the potential for avoidable blindness in children presenting to clinicians with features suggestive of LCP disease but with underlying Stickler syndrome and proposes a simple scoring system to assist clinicians.

Growth-related sports injuries among young male professional football players in the Netherlands: a prospective cohort study concerning injury incidence, severity and burden

OBJECTIVES

To investigate the incidence, type and location of growth-related sports injuries (GRSI) in youth professional football in the Netherlands. Secondary, to gain more knowledge on the injury severity and burden of GRSI.

METHODS

In this prospective, longitudinal cohort study, 813 players aged 10-18 are included. Data collection is performed by instructing the medical staff of six professional football club academies to register GRSI by means of standardized forms. Training and match exposure are registered individually on a weekly basis. Injury incidence was calculated as number of GRSI per 1000 hours, injury severity as the median number of days lost in categories and injury burden as the number of days lost per 1000 hours.

RESULTS

A total of 62 GRSI were documented in the football season 2021-2022. The total incidence of GRSI was 0.62/1000 hours football exposure. Morbus Osgood Schlatter and Morbus Sever were most common types of GRSI, both with incidence rates of 0.22/1000 hours exposure. About 58.3% of the documented GRSI were classified as major (>28 days lost). Within this group, the mean severity was 55 days time-loss to football.

CONCLUSIONS

GRSI are relatively common in youth professional football. The most common types are Morbus Sever and Morbus Osgood Schlatter. Morbus Osgood Schlatter has the highest injury severity and burden compared to other types of GRSI.

Association between Polymorphism eNOS4, tPA, Factor V Leiden, Prothrombin, and Methylenetetrahydrofolate Reductase and the Occurrence of Legg-Calvé-Perthes Disease

BACKGROUND

Legg-Calvé-Perthes (LCPD) disease is a complex condition affecting the femoral head's epiphysis in children. It occurs with a prevalence ranging from 0.4 to 29.0 cases per 100,000 children under the age of 15. It involves various factors, including genes associated with coagulation and fibrinolysis, pro-inflammatory factors, and vasoactive substances.

METHODS

We investigated the relationship between genetic mutations associated with coagulation and vascular disorders and the occurrence of LCPD in Polish patients. We performed a study involving 25 patients with LCPD and 100 healthy controls. All subjects were genotyped for eNOS4, Factor V Leiden, prothrombin, tPA25, and MTHFR polymorphism.

RESULTS

The analysis revealed that the frequencies of eNOS4 genotypes were significantly different in LCPD patients than in the control group (p = 0.018). The frequencies of 4a allele were significantly higher in patients with LCPD than in the healthy population (26% vs. 9%, p = 0.0012). There were no significant differences in genotype and allele frequencies for Factor V Leiden, prothrombin tPA 25, and MTHFR gene polymorphisms between patients with LCPD and the controls.

CONCLUSIONS

Genotype and allele frequencies of eNOS4 were significantly higher in patients with LCPD. These findings suggest a potential association between the eNOS gene polymorphism and an increased risk of developing LCPD.

Inhibition of Toll-Like Receptor 4 Signaling Pathway Accelerates the Repair of Avascular Necrosis of Femoral Epiphysis through Regulating Macrophage Polarization in Perthes Disease

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) is still a refractory disease in children's orthopedics. With the introduction of the concept of "osteoimmunology", the immune-inflammatory mechanisms between bone and immune system have become a research focus of LCPD. However, few studies have reported on the pathological role of inflammation-related receptors such as toll-like receptors (TLRs) as well as immune cells such as macrophages in LCPD. This study was for investigating the mechanism of TLR4 signaling pathway on the direction of macrophage polarization and the repair of avascular necrosis of femoral epiphysis in LCPD.

METHODS

With GSE57614 and GSE74089, differentially expressed genes were screened. Through enrichment analysis and protein-protein interaction network, the functions of TLR4 were explored. Furthermore, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA), hematoxylin & eosin (H&E) staining, micro-CT, tartrate-resistant acid phosphatase (TRAP) dyeing and western blotting were performed for determining the influences of TAK-242 (a TLR4 inhibitor) on the repair of avascular necrosis of femoral epiphysis in rat models.

RESULTS

Totally 40 co-expression genes were screened as well as enriched in TLR4 signaling pathway. Immunohistochemistry and ELISA analyses certified that TLR4 facilitated macrophage polarization toward the M1 phenotype and prevented macrophage polarization toward the M2 phenotype. Besides, the results of H&E and TRAP staining, micro-CT, and western blotting showed that TAK-242 can inhibit osteoclastogenesis and promote osteogenesis.

CONCLUSION

Inhibition of TLR4 signaling pathway accelerated the repair of avascular necrosis of femoral epiphysis by regulating macrophage polarization in LCPD.

Construction of ceRNA network based on RNA-seq for identifying prognostic lncRNA biomarkers in Perthes disease

Introduction: Legg-Calvé-Perthes disease or Perthes disease is a condition that occurs in children aged 2 to 15 years, and is characterized by osteonecrosis of the femoral head, which results in physical limitations. Despite ongoing research, the pathogenesis and molecular mechanisms underlying the development of Perthes disease remain unclear. In order to obtain further insights, the expression patterns of long non-coding RNAs (lncRNAs), miRNAs, and mRNAs in a rabbit model of Perthes disease were analyzed in this study by transcriptome sequencing. Methods and results: The results of RNA-seq analyses revealed that 77 lncRNAs, 239 miRNAs, and 1027 mRNAs were differentially expressed in the rabbit model. This finding suggested that multiple genetic pathways are involved in the development of Perthes disease. A weighted gene co-expression network analysis (WGCNA) network was subsequently constructed using the differentially expressed mRNAs (DEmRNAs), and network analysis revealed that the genes associated with angiogenesis and platelet activation were downregulated, which was consistent with the findings of Perthes disease. A competing endogenous RNA (ceRNA) network was additionally constructed using 29 differentially expressed lncRNAs (including HIF3A and LOC103350994), 28 differentially expressed miRNAs (including ocu-miR-574-5p and ocu-miR-324-3p), and 76 DEmRNAs (including ALOX12 and PTGER2). Disscusion: The results obtained herein provide novel perspectives regarding the pathogenesis and molecular mechanisms underlying the development of Perthes disease. The findings of this study can pave the way for the development of effective therapeutic strategies for Perthes disease in future.

Pedicled iliac bone flap grafting in the treatment of late presentation Legg–Calvé–Perthes disease

Background

Legg–Calvé–Perthes disease (LCPD) is a juvenile form of ischemic femoral head osteonecrosis affecting children. The lack of effective and timely treatment results in severe sequelae in children (especially older ones). Although LCPD has been widely studied, little is known about its etiology. As a result, its clinical management is still challenging. This study will investigate the clinical and radiological results of patients older than 6 years and treated with pedicled iliac bone flap grafting for LCPD.

Materials and methods

A total of 13 patients (13 hips) with late presentation of LCPD were treated with pedicled iliac bone flap grafting. Of the 13 patients, 11 were male and 2 were female. The average age of the patients was 8.4 years (range 6–13). Preoperational radiographs and pain scores were analyzed for lateral pillar classification and the Oucher scale. The final follow-up radiograph was classified using a modified Stulberg classification. Limping, extremity length inequality, and range of motion were clinically assessed.

Results

The average follow-up of the patients was 70 months (range 46–120). During the surgery, seven hips were found to be lateral pillar grade B, two were grade B/C, and four were grade C. In the final examination, 12 hips were evaluated as good (Stulberg class I or II) and one as medium (Stulberg class III). There was limb shortening in one patient who was Stulberg class III. There was a significant difference between the preoperational and postoperational radiographic values and the Ocher scale, regardless of the surgical staging (P < 0.05).

Conclusions

Pedicled iliac bone flap graft can treat LCPD accompanied by pain and lateral pillar stage B, B/C, and C in children over 6 years.

Level of Evidence

Level IV—case series.

Case study of Legg-Calvé-Perthes disease observed in Radom (Poland, 18th–19th century) with literature review

The aim of this study is to present the pathological lesions observed in a skeleton (male, about 35–38 years old) from Radom (Poland), dated to the 18th–19th century. Bone changes were observed in both femurs and both pelvic bones. The head of the femur is enlarged and deformed, described as “mushroom-shaped”, with areas of smooth cortex and cavities, or possible cystic residues. The neck of femur is short and thick. The bone shaft and distal epiphysis do not show any changes. The changes were also observed in both acetabularies of the hip joint (marginal bone formation, subchondral bone remodelling). Radiographic images show bilateral necrosis of the femoral head. There is a significant sclerotization of the femoral head, with a discrete visible crescent sign. These macroscopic and radiological changes match the symptoms associated with Legg-Calvé-Perthes disease. This is the first case of the disease described in bioarchaeological materials from Poland.

Platelet to lymphocyte ratio was a risk factor in Perthes disease

The study was aimed to determine the relationship between PLR (platelet to lymphocyte ratio) and the lateral pillar classification of Perthes disease, and to provide an alternative index for clinical diagnosis. In addition, the association of the PLR with the necrosis stage of Perthes disease was also explored. This was a retrospective study. 74 children with Perthes disease and 60 children in the healthy control group without femoral head necrosis in our hospital from 2012 to 2021 were collected. The general data and clinical parameters were collected from the hospital information system. The modified herring lateral pillar classification was collected for the fragmentation stage case group and the PLR, NLR (neutrophil to lymphocyte ratio), LMR (lymphocyte to monocyte ratio) and PNR (platelet to neutrophil ratio) were calculated. The cases were divided into four groups, herring A and B were group I, herring B/C and C were group II, the healthy control group was group III, and the necrosis stage was group IV. The hematological indexes (NLR, PLR, LMR, PNR) of children at different stages were statistically analyzed. Group I consisted of 36 patients, with an average age of 7.4 ± 2.0 years (3-11 years). Group II consisted of 23 patients, with an average age of 7.4 ± 1.9 years (4-12 years). Group III consisted of 60 patients, with a mean age of 7.4 ± 2.7 years (4-13 years). Group IV consisted of 15 patients, with an average age of 6.4 ± 1.7 years (3-10 years). The average values of PLR in groups I, II, III and IV were 131.98 ± 47.44, 122.19 ± 37.88, 102.46 ± 30.68 and 128.90 ± 28.11, respectively. It's worth noting that there was statistically significant difference among groups I, II and III (P = 0.003). The optimal threshold of PLR was 130.25, the sensitivity was 45.8% and the specificity was 85%. PLR was also significantly different between groups III and group IV. PLR was higher in Herring A and B classifications than in Herring B/C and C classifications. PLR had certain diagnostic value in both the necrosis stage and fragmentation stage as a risk factor.

Molecular Biomarkers in Perthes Disease: A Review

BACKGROUND

Perthes disease is a juvenile form of osteonecrosis of the femoral head that affects children under the age of 15. One hundred years after its discovery, some light has been shed on its etiology and the biological factors relevant to its etiology and disease severity.

METHODS

The aim of this study was to summarize the literature findings on the biological factors relevant to the pathogenesis of Perthes disease, their diagnostic and clinical significance, and their therapeutic potential. A special focus on candidate genes as susceptibility factors and factors relevant to clinical severity was made, where studies reporting clinical or preclinical results were considered as the inclusion criteria. PubMed databases were searched by two independent researchers. Sixty-eight articles were included in this review. Results on the factors relevant to vascular involvement and inflammatory molecules indicated as factors that contribute to impaired bone remodeling have been summarized. Moreover, several candidate genes relevant to an active phase of the disease have been suggested as possible biological therapeutic targets.

CONCLUSIONS

Delineation of molecular biomarkers that underlie the pathophysiological process of Perthes disease can allow for the provision of earlier and more accurate diagnoses of the disease and more precise follow-ups and treatment in the early phases of the disease.

Surgical hip dislocation with relative femoral neck lengthening and retinacular soft-tissue flap for sequela of Legg–Calve–Perthes disease

Objective

Correction of post-LCP (Legg–Calve–Perthes) morphology using surgical hip dislocation with retinacular flap and relative femoral neck lengthening for impingent correction reduces the risk of early arthritis and improves the survival of the native hip joint.

Indications

Typical post-LCP deformity with external and internal hip impingement due to aspherical enlarged femoral head and shortened femoral neck with high riding trochanter major without advanced osteoarthritis (Tönnis classification ≤ 1) in the younger patient (age < 50 years).

Contraindications

Advanced global osteoarthritis (Tönnis classification ≥ 2).

Surgical technique

By performing surgical hip dislocation, full access to the hip joint is gained which allows intra-articular corrections like cartilage and labral repair. Relative femoral neck lengthening involves osteotomy and distalization of the greater trochanter with reduction of the base of the femoral neck, while maintaining vascular perfusion of the femoral head by creation of a retinacular soft-tissue flap.

Postoperative management

Immediate postoperative mobilization on a passive motion device to prevent capsular adhesions. Patients mobilized with partial weight bearing of 15 kg with the use of crutches for at least 8 weeks.

Results

In all, 81 hips with symptomatic deformity of the femoral head after healed LCP disease were treated with surgical hip dislocation and offset correction between 1997 and 2020. The mean age at operation was 23 years; mean follow-up was 9 years; 11 hips were converted to total hip arthroplasty and 1 patient died 1 year after the operation. The other 67 hips showed no or minor progression of arthrosis. Complications were 2 subluxations due to instability and 1 pseudarthrosis of the lesser trochanter; no hip developed avascular necrosis.

Outcomes in Pediatric Hip FAI Surgery: a Scoping Review

PURPOSE OF REVIEW

Femoracetabular impingement (FAI) is a common source of hip pain in children and adolescents. While nonoperative therapies and open surgical procedures can be effective, hip arthroscopy is a minimally invasive treatment option with substantial benefit. The purpose of this paper is to evaluate the current role of hip arthroscopy in treating FAI within the pediatric population. This article examines its efficacy through a review of hip arthroscopy outcomes in the contemporary orthopaedic literature.

RECENT FINDINGS

Morphologic changes in the acetabulum and proximal femur seen in FAI can be attributed to a multitude of etiologies-including idiopathic FAI, Legg-Calve-Perthes, and slipped capital femoral epiphysis. In general, arthroscopic treatment of FAI secondary to these conditions leads to statistically significant improvements in pain and patient-reported outcomes in the short and long term. In the pediatric athlete, repetitive stress on the hip perpetuates FAI and can drastically hinder performance. Hip arthroscopy allows for a high rate of return to sport with minimal morbidity in this population. Overall, pediatric hip arthroscopy is effective in treating FAI secondary to a wide variety of conditions. Despite its clinical benefits, patients and their families should be counseled regarding alternative treatments, potential complications, and return to play.

Mid–Long-Term Outcomes of Surgical Treatment of Legg-Calvè-Perthes Disease: A Systematic Review

Background: Legg–Calvè–Perthes disease (LCPD) is a common childhood disease that usually occurs in 4- to 12-year-old children. Surgical treatment consists of femoral, pelvic, or combined osteotomies. This comprehensive review aimed to investigate the mid- and long-term outcome of the surgical treatment. Methods: A systematic review of PubMed, Science Direct, and MEDLINE databases was performed by two independent authors, using the keywords “outcome”, “surgical treatment”, “pelvic osteotomy”, “femoral osteotomy”, and “Legg–Calvè–Perthes disease” to evaluate studies of any level of evidence that reported the surgical outcome of LCPD. The result of every stage was reviewed and approved by two senior investigators. Results: A total of 2153 articles were found. At the end of the screening, we selected 23 articles eligible for full-text reading according to the inclusion and exclusion criteria. Our analysis showed that the main prognostic factors for surgical outcome in patients with LCPD are the age at onset and the degree of initial disease severity. Conclusions: Surgical treatment in patients older than 6 years has excellent results in Herring B and B/C hips and poor results in Herring C hips, with a slight advantage for patients between 6 and 8 years old.

Perthes Disease in a Child With Osteogenesis Imperfecta From a Rare Genetic Variant: A Case Report

Background: Although certain genetic components have been reported as contributing factors for Perthes disease, its etiology remains unclear. We present a rare case of Perthes disease in a child with osteogenesis imperfecta (OI) caused by a mutation in the COL1A1 gene (NM_000088):exon25:c.1726C>T, (p.Gln576X).

Case presentations: A 7-year-old boy was initially treated at our medical facility in March 2016 with a history of chronic pain in right hip joint and limping for a year. He was diagnosed as Perthes disease in the right hip joint. He underwent acetabular osteotomy and ipsilateral proximal femoral varus osteotomy for better containment. During the follow-ups, the right hip demonstrated a normal range of motion without pain, and the pelvic X-ray demonstrated Stulberg Type II hip joint with a round femoral head. In the latest admission in 2022, he suffered from a right femoral shaft fracture after petty violence. After reviewing his medical history, he was suspected of having OI. The whole exome sequencing demonstrated a gene mutation in COL1A1 (OMIM 166200) and confirmed the diagnosis of OI. Telescopic nailing was used to treat the femoral shaft fracture. After the nailing of the right femur, the appearance of the lower extremity seemed normal and symmetrical.

Conclusion: This study revealed that there might be an association between OI and Perthes disease. Our case report enriches the phenotypes of osteogenesis imperfecta and provides insight into the pathogenesis of LCPD.

Legg-Calvé-Perthes disease overview

Background

Legg–Calvé–Perthes Disease (LCPD) is a necrosis of the femoral head which affects the range of motion of the hips. Its incidence is variable, ranging from 0.4/100,000 to 29.0/ 100,000 children. Although LCPD was first described in the beginning of the past century, limited is known about its etiology. Our objective is to describe the main areas of interest in Legg–Calve–Perthes disease.

Methods

A review of the literature regarding LCPD etiology was performed, considering the following inclusion criteria: Studies reporting clinical or preclinical results. The research group carried out a filtered search on the PubMed and Science Direct databases. To maximize the suitability of the search results, we combined the terms ‘‘Perthes disease” OR “LCPD” OR “children avascular femoral head necrosis” with “diagnostic” OR “treatment” OR “etiology” as either key words or MeSH terms.

Results

In this article been described some areas of interest in LCPD, we include topics such as: history, incidence, pathogenesis, diagnosis, treatment and possible etiology, since LCPD has an unknown etiology.

Conclusions

This review suggests that LCPD has a multifactorial etiology where environmental, metabolic and genetic agents could be involved.

Society of Toxicologic Pathology Nonhuman Primate Special Interest Group: Idiopathic Femoral Head Chondrolysis in Nonclinical Research Macaques

Idiopathic femoral head chondrolysis is a recognized condition in human adolescents and has previously been reported in two macaques at a biomedical research facility. A cluster of coxofemoral joint abnormalities consistent with this condition affecting seven cynomolgus macaques over a four-month period in 2016 and 2017 was observed at a single, nonclinical contract research facility, prompting enhanced physical examination screening efforts during animal receipt and pre-study evaluation to identify additional affected animals. This article summarizes the results of this investigation from November 2016 to March 2021, yielding 97 total cases for an overall incidence of 0.54% (97/17,898 macaques). Affected animals were presented with one or more of the following unilateral or bilateral findings on physical examination and/or diagnostic imaging: lameness, palpable coxofemoral joint abnormalities, femoral head atrophy with variable loss of articular cartilage and irregularity of the femoral head surface, enlarged joint space with effusion, and increased radiographic density of the femoral head. This condition prevented use of affected animals on study for 54% of the cases (52/97 animals). Recognition of this idiopathic condition is important in drug safety evaluation studies to distinguish it from test article-related effects.

Increased psoas tendon running angle in patients with Legg-Calvé-Perthes disease: a new theory for the aetiology of children with avascular femoral head necrosis

The cause of Legg-Calvé-Perthes disease (LCPD) remains unknown. We propose a new hypothesis that the iliopsoas muscle and/or tendon affects the progression of ischemic necrosis of the femoral head as an anatomical factor. The purpose of this study was to test this hypothesis by measuring the psoas major tendon angle (PMTA) and cross-sectional area (CSA) of the iliopsoas muscle on MRI. We selected three predetermined axial MRI scans at the level of the psoas major tendon origin, the femoral head, and the lesser trochanter. We calculated the proximal, distal, and combined PMTA and compared these angles between the LCPD group and the transient synovitis (TS) group as a control. Our results revealed that the proximal PMTAs of the LCPD-affected sides were significantly greater than in the TS controls (P < 0.05), while there were no significant differences in the proximal PMTA, combined PMTA, and CSA. This result indicates that the psoas major tendon of the patient with LCPD curves sharply on the anterior capsule of the hip joint more than in the control group patients. This sudden curve of the psoas major tendon may be involved in the development of LCPD. We measured PMTAs in patients with LCPD. Our findings suggested that the running curve of the psoas major tendon is an anatomical factor that influences the development of mechanically-induced ischemia in LCPD.

Prevalence of and Associations With Avascular Necrosis After Pediatric Sepsis: A Single-Center Retrospective Study

OBJECTIVES

Avascular necrosis (AVN) is a rare, but serious, complication after sepsis in adults. We sought to determine if sepsis is associated with postillness diagnosis of AVN, as well as potential-associated risk factors for AVN in children with sepsis.

DESIGN

Retrospective observational study.

SETTING

Single academic children's hospital.

PATIENTS

Patients less than 18 years treated for sepsis or suspected bacterial infection from 2011 to 2017. Patients who developed AVN within 3 years after sepsis were compared with patients who developed AVN after suspected bacterial infection and with patients with sepsis who did not develop AVN.

INTERVENTION

None.

MEASUREMENTS AND MAIN RESULTS

AVN was determined using International Classification of Diseases, 9th Edition/10th Edition codes and confirmed by chart review. The prevalence of AVN after sepsis was 0.73% (21/2,883) and after suspected bacterial infection was 0.43% (53/12,276; risk difference, 0.30; 95% CI, 0.0-0.63; p = 0.05). Compared with 43 sepsis controls without AVN, AVN in the 21 sepsis cases was associated with being older, having sickle cell disease and malignancy, higher body mass index, unknown source of infection, and low platelet count in the first 7 days of sepsis. Half of sepsis patients were treated with corticosteroids, and higher median cumulative dose of steroids was associated with AVN (23.2 vs 5.4 mg/kg; p < 0.01). Older age at infection (odds ratio [OR], 1.3; 95% CI, 1.1-1.4), malignancy (OR, 8.8; 95% CI, 2.6-32.9), unknown site of infection (OR, 12.7; 95% CI, 3.3-48.6), and minimal platelet count less than 100,000/µL in first 7 days of sepsis (OR, 5.0; 95% CI, 1.6-15.4) were identified as potential risk factors for AVN after sepsis following adjustment for multiple comparisons.

CONCLUSIONS

Although rare, sepsis was associated with a higher risk of subsequent AVN than suspected bacterial infection in children. Older age, malignancy, unknown site of infection, and minimum platelet count were potential risk factors for AVN after sepsis.

MicroRNA sequence analysis of plasma exosomes in early Legg-Calvé-Perthes disease

The pathogenesis of Legg-Calvé-Perthes disease (LCPD) has not been fully elucidated, and studies on epigenetic changes that may contribute to the pathogenesis of LCPD are rare. MicroRNAs (miRNAs) are epigenetic modifications that play a critical role in gene regulation. This study aimed to determine the expression profiles of circulating exosomal miRNAs and examine the role of exosomal miRNAs in LCPD. Exosomes were extracted from the plasma of three patients with LCPD and three matched healthy volunteers. Total exosomal miRNAs were isolated, and next-generation sequencing and bioinformatic approaches were performed. The top 10 most differentially upregulated miRNAs were identified, and qRT-PCR validation was performed using additional 10 matches. In Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, plasma exosomes were used in verifying osteoclastogenesis and the endothelial dysfunction phenotypes involved. The elevated miRNAs in LCPD plasma exosomes were tested for osteoclastogenesis and endothelial dysfunction in vitro. Sequencing results revealed the expression profiles of plasma exosomal miRNAs with differential expression from the DESeq-identified miRNA profiles in LCPD versus controls in a pairwise comparison. Gene Ontology and KEGG pathway analyses indicated that the predicted target genes of different miRNAs were mainly enriched in the endothelial and osteoclast cells related to signaling pathways. Functional phenotype experiments showed that the plasma exosomes in the LCPD group promoted osteoclastogenesis and endothelial cell dysfunction. qRT-PCR experiments showed that nine miRNAs in circulating exosomes in LCPD patients were higher than those in the healthy controls. miR-3133, miR-4644, miR-4693-3p, and miR-4693-5p promoted endothelial dysfunction, and miR-3133, miR-4693-3p, miR-4693-5p, miR-141-3p and miR-30a promoted osteoclastogenesis in vitro. This study demonstrated that plasma exosomes from LCPD promote endothelial cell dysfunction and osteoclastogenesis likely through their miRNAs, which might contribute to the development of LCPD.

Association of IL-6 -174G > C and -572G > C Polymorphisms with Risk of Legg-Calve-Perthes Disease in Iranian Children

Legg-Calve-Perthes disease (LCPD) is an idiopathic avascular necrosis of the capital femoral epiphysis of the femoral head with multifactorial etiology. The aim of this study was to analyze the association of IL-6 polymorphisms with LCPD risk in Iranian children. Methods: The study comprised of 45 children diagnosed with LCPD and 60 healthy subjects. The IL-6 -174 G > C and -597 G > C polymorphisms were genotyped by PCR-RFLP assay. Odds ratios (OR) and 95% confidence intervals (CI) were calculated on the risk genotypes and alleles. Results: The mutant homozygote genotype (CC) of IL-6 -174 G > C polymorphism was associated with increased risk of LCPD (OR 3.554; 95% CI: 0.1.578-8.004; p = 0.002). There was no significant association between IL-6 -597 G > C polymorphism and an increased risk of LCPD. Conclusions: Our results suggest that the IL-6 -174 G > C but not the IL-6 -597 G > C polymorphism may increase LCPD susceptibility in Iranian children.

Does early and aggressive management of significant extrusion of the femoral head affect the outcome of Perthes' disease with the age of onset younger than 7 years?

Background

Little literature exists regarding aggressive treatment of the extrusion in the early stage of the disease and the outcome at skeletal maturity. The purpose of the study was to evaluate the outcome of the disease with onset younger than 7 years, treated in the early stage of the disease, with aggressive management of significant extrusion (immediate containment with fixed abduction brace in children less than 5 years and varus derotation osteotomy in older children), and reached skeletal maturity.

Methods

All children with the age of onset younger than 7 years of disease during active Perthes disease were prospectively followed. Children with early stages of the disease (modified Elizabethtown classification) and reached skeletal maturity were included (68 children). The extrusion of the femur head was calculated by Reimer’s migration index on both sides. A migration difference 12 % or above was considered as “significant extrusion”. Children without significant extrusion were treated non-operatively; children with significant extrusion were treated with varus derotation osteotomy. The final radiological outcome was assessed by the Stulberg classification and sphericity deviation score (SDS). The independent “t” test and Chi-square test were done to compare the difference between the two groups.

Results

The mean age at the onset and the final follow-up was 5.7 years and 15.3 years. The frequency of significant extrusion was 57%. At the final follow-up, an excellent clinical outcome and radiological outcomes (in 88% hips) were noted. There was no significant difference in the Stulberg groups and SDS (sphericity deviation score) in both groups.

Conclusion

The outcome of the children who had the age of onset of the disease less than 7 years was good with early and aggressive management of the extrusion. The reversal of extrusion is associated with a similar result of non-operative children in this age group.

Level of evidence

III.

Towards a definition of Ancient Rare Diseases (ARD): Presenting a complex case of probable Legg-Calvé-Perthes Disease from the North Caucasian Bronze Age (2200-1650 cal BCE)

OBJECTIVE

This study discusses the challenges and possibilities of establishing a definition for Ancient Rare Diseases (ARD) in a probable case of Legg-Calvé-Perthes Disease (LCPD) from the Bronze Age cemetery Kudachurt 14, situated in the Northern Caucasus.

MATERIALS

We investigated the skeletal remains of a male aged 35-45 years at death. For comparison we examined other males buried at Kudachurt 14 (n = 24) and reviewed 22 LCPD cases from the paleopathological literature.

METHODS

We use macroscopic as well as osteometric examination methods and imaging techniques.

RESULTS

The morphology of the left hip joint corresponds to skeletal characteristics for LCPD. Co-occurring osteochondrosis dissecans, femoral anteversion, and atrophy of the left femoral shaft suggest a complex disease course.

CONCLUSIONS

Modern criteria of rare diseases applied on ancient skeletal remains are either non-transferable or require completion. We conclude that rarity is dynamic, etiological uncertainty has to be accepted, and the respective socioeconomic context is crucial. Degree of disability and level of sociomedical investment are not defining criteria for ARD.

SIGNIFICANCE

Dating 2200-1650 cal BCE, this study currently presents the earliest case of probable LCPD. This is the first attempt to transform modern characteristics of rare diseases for establishing a paleopathological concept of ARD.

LIMITATIONS

As this study is limited to LCPD, our conclusions are not directly applicable to other ARD in question.

SUGGESTIONS FOR FURTHER RESEARCH

More focused paleopathological research on skeletal populations from different cultures and time periods is needed, enabling an evolutionary perspective on the comparability of ancient, modern and future rare diseases.

High blood pressure and overweight in children with Legg-Calvé-Perthes disease: a nationwide population-based cohort study

Purpose

Legg-Calvé-Perthes disease (LCPD) and its association with cardiovascular diseases, obesity and hypertension has been consistently observed but remains cloudy. This study aimed to investigate the presence of hypertension and overweight/obesity at diagnosis of LCPD and at a 2-year follow-up and its association with age, sex and lateral pillar classification.

Method

We compared blood pressure (BP) (n = 93) and body mass index (BMI) (n = 125) in patients registered in the Perthes’ register - a part of the Swedish pediatric orthopedic quality register (SPOQ) - with normative data for children with the same age and sex.

Results

In children with LCPD 19% had high BP. At the 2-year follow-up, 13% had high BP. For children with LCPD, 30% were either overweight or obese. At the 2-year follow-up, 32% were either overweight or obese. Paired analysis showed stable BMI z-score between these 2 measurements. The sample size of this study was too small to analyze possible associations of high BP or BMI with age, sex and lateral pillar classification.

Conclusions

The prevalence of hypertension was higher in children with LCPD compared to general pediatric normative data. The same pattern was seen for overweight/obesity. Further studies are needed to investigate whether BP and obesity are catalyzing factors in the etiology of LCPD.

Increased circulating CD31+/CD42b-EMPs in Perthes disease and inhibit HUVECs angiogenesis via endothelial dysfunction

AIMS

Endothelial microparticles (EMPs) are extracellular vesicles secreted by endothelial cells. The purpose of this research is to explore that the clinical significance and roles in angiogenesis and endothelial dysfunction of circulating microparticles in Perthes disease.

MAIN METHODS

We collected platelet-poor plasma (PPP) from patients and controls, then microparticles (MPs) were extracted. Flow cytometry was performed to calculate the concentrations of CD31+/CD42b-, CD62E+ and CD31+/CD42b+ MPs. ELISA was performed to detect the expression level of biomarkers of endothelial dysfunction and inflammatory factors in plasma. In vitro experiments to evaluate the effect of circulating MPs and EMPs derived from IL-6-stimulated human umbilical vein endothelial cells (HUVECs) on angiogenesis and endothelial dysfunction.

KEY FINDINGS

Our results revealed that the CD31+/CD42b- EMPs were significantly higher in Perthes disease group than in the control group. The Perthes-MPs being taken up by HUVECs promoted endothelial cell apoptosis, endothelial dysfunction and inhibited angiogenesis in vitro. Moreover, the level of IL-6 in plasma significantly increased in patients with Perthes, which was tightly correlated with the elevated level of circulating CD31+/CD42b- EMPs. IL-6 promoted HUVECs to secrete CD31+/CD42b- MPs, and EMPs derived from high concentration IL-6-stimulated (100 and 1000 pg/mL) HUVECs promoted endothelial cell apoptosis, endothelial dysfunction and inhibited angiogenesis.

SIGNIFICANCE

In summary, our study suggests that circulating EMPs in the phenotypic spectrum revealed unique phenotypes of endothelial dysfunction, showing close correlation with the secretion of IL-6. These circulating EMPs may give rise to endothelial cell apoptosis, endothelial dysfunction and angiogenesis in Perthes disease.

Influence of passive smoking on the onset of Legg-Calvè-Perthes disease: a systematic review and meta-analysis

The relationship between passive smoking and the onset of Legg-Calvè-Perthes disease is still controversial. Therefore, we conducted the study to systematically evaluate and analyze the relationship. A comprehensive search was conducted. Meta-analysis was performed with RevMan 5.3 software, with the odds ratio as the effect size. Eight English articles with a total of 1379 Legg-Calvè-Perthes disease patients were eventually included. Passive smoking type of family members smoking in indoor (odds ratio = 2.53), paternal smoking (odds ratio = 2.76), maternal smoking (odds ratio = 2.02), maternal smoking during pregnancy (odds ratio = 1.68), using stove indoor (odds ratio = 2.56) are statistically significant (P < 0.05). For the family members smoking indoor, region may be a confounding factor (European group I = 92%, odds ratio = 2.51; USA group I = 5%, odds ratio = 3.26; and Asian group I = 0%, odds ratio = 2.25). In addition, the type of maternal smoking (odds ratio = 0.80, for 1-10 per day; odds ratio = 2.73, for 10-20 per day; odds ratio = 2.78, for >20 per day) and the type of maternal smoking during pregnancy (odds ratio = 1.36, for 1-9 per day; odds ratio = 2.02, for ≥10 per day) may show a dose-effect relationship. Passive smoking is a risk factor for the onset of Legg-Calvè-Perthes disease, but the specific types of passive smoking (haze, etc.), dose, dose-effect relationship, regional confounding, pathological mechanisms, etc. also require clinicians and researchers to continue exploring.

Impingement-free hip range of motion after osteochondroplasty and relative neck lengthening in adults with healed Perthes disease

Objective

Our main objective is to assess the efficiency of the osteochondroplasty with relative neck lengthening in adults with healed Perthes clinically (through assessment of impingement-free hip ROM, functional scores) and radiographically.

Patients and methods

This was a prospective case series study included 30 hips of 30 patients who underwent osteochondroplasty and RNL due to symptomatic healed LCPD. This study included 16 males (53.3%) and 14 females (46.7%). The age of patients ranged from 19 to 40 years with mean age 26.4 years at the date of surgery (SD 6.4).

Results

Median time of follow-up was 27.7 months after surgery (range 12–60 months). Two patients (6.6%) developed avascular necrosis (AVN) and needing total hip replacement; none of our patients developed nerve injury, detachment of the trochanteric fragment, and wound infection needing treatment. Preoperative Stulberg classes II and III improved more than preoperative Stulberg classes IV and V, although not statistically significant (P = 0.1104, n = 30). The mean HHS and WOMAC score values for each patient were higher in the Stulberg II and III groups compared to the Stulberg IV and V groups

Conclusion

Head and neck osteochondroplasty performed through the surgical dislocation approach, combined with RFNL, relieved pain and restored function in most of the patients with reasonable complications.

Level of evidence

IV

Diagnostik und Therapie des Morbus Perthes

Die Behandlung des M. Perthes stellt aufgrund der ungeklärten Ätiologie sowie der unterschiedlichen Verlaufsformen und Behandlungskonzepte eine Herausforderung dar. Die Prognose ist abhängig von klinischen und radiologischen Parametern. Aktuelle Behandlungsansätze zielen in frühen Krankheitsstadien auf die Verbesserung der Durchblutung des Femurkopfes und später auf die Vergrößerung des Bewegungsumfangs sowie die Verminderung der vertikal einwirkenden Kräfte durch Teilentlastung und chirurgisch verbesserte Einstellung des Femurkopfes in der Gelenkpfanne ab. Da einerseits ein hoher Prozentsatz an Spontanremissionen ohne Deformitäten des Gelenks, andererseits ein hohes Risiko für eine schwere Koxarthrose mit der Notwendigkeit eines frühen Gelenkersatzes sowohl nach konservativen als auch nach operativen Verfahren zu beobachten sind, werden die Behandlungsmethoden kontrovers diskutiert.

[Perthes disease: immunological aspects.]

The values of cellular, humoral immunity, cytokine status, those of phagocytic activity of neutrophils (PAN) have been studied in patients with Perthes disease II and III Stages. Considering a stage of the pathological process patients (boys at the age of 8-12 years) were divided into two (2) groups. Group I included 14 patients with the fragmentation stage (Perthes disease Stage II). Group 2 include d 15 children with Perthes disease Stage III (the stage of re-ossification). Perthes disease regardless of the stage of the disease was characterized by the increase in oxygendependent and lysosomal phagocytic activity of neutrophils, the increase in the number of early extracellular traps, as well as by increased concentrations of pro-inflammatory cytokines (IL-1β and TNFa), IgЕ, decreased concentrations of IL-18. The fragmentation stage was characterized by moderate activation of cellular immunity with a prevailing increase in the number of T-lymphocytes with early activation markers (CD25). At the re-ossification stage the predominance of T-lymphocytes was observed with late activation markers (HLADR), being accompanied by moderate activation of humoral immunity (increased concentrations of class A and G serum immunoglobulins). The obtained data can be used as additional criteria for clarifying Perthes disease stage, predicting osteonecrosis development when making decision of the feasibility of performing reconstructive surgeries on the joint.