Is Legg-Calvé-Perthes Disease a Local Manifestation of a Systemic Condition?

Demographics and risk for containment surgery in patients with unilateral Legg-Calvé-Perthes disease: a national population-based cohort study of 309 patients from the Swedish Pediatric Orthopedic Quality Register

BACKGROUND AND PURPOSE

It is controversial as to which patients affected by Legg-Calvé-Perthes disease (LCPD) benefit from containment surgery. This population-based study based on data from a national quality registry aims to assess the incidence of LCPD and to explore which factors affect the decision for surgical intervention.

METHODS

This observational study involved 309 patients with unilateral LCPD reported between 2015 and 2023 to the Swedish Pediatric Orthopedic Quality Register (SPOQ). Descriptive statistics and logistic regression models were used for analysis.

RESULTS

In 2019, the assessed incidence of LCPD in the Swedish population of 2-12-year-olds was 4.2 per 105. 238 (77%) were boys with a mean age of 6 years. At diagnosis, 55 (30%) were overweight or obese, rising to 17 patients (39%) and 16 patients (40%) at 2-year follow-up for surgically and non-surgically treated groups, respectively. At diagnosis, affected hips had reduced abduction compared with healthy hips, and their abduction remained restricted at the 2-year follow-up. Surgically treated patients had inferior abduction compared with non-surgically treated ones at diagnosis. The adjusted risk for containment surgery increased with age and in the presence of a positive Trendelenburg sign but decreased with greater hip abduction.

CONCLUSION

We found a lower national yearly incidence (4.2 per 105) than previously reported in Swedish studies. A higher proportion of overweight or obese patients compared with the general Swedish population of 4-9-year-olds was identified. Increasing age, positive Trendelenburg sign, and limited hip abduction at diagnosis correlated with increased surgical intervention likelihood.

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.

Exosomes from chondrocytes overexpressing miR-214-3p facilitate M2 macrophage polarization and angiogenesis to relieve Legg Calvé-Perthes disease

OBJECTIVE

Legg-Calvé-Perthes disease (LCPD) is a partial or total necrosis of femoral head bone caused by blood supply disorder and its etiology is not clear. Studies have revealed that microRNA-214-3p (miR-214-3p) plays a vital role in LCPD, however, its exact mechanism is still unclear. In this study, we investigated the potential role of chondrocytes-derived exosomes carrying miR-214-3p (exos-miR-214-3p) in the pathogenesis of LCPD.

METHODS

RT-qPCR was performed to evaluate miR-214-3p expression level in femoral head cartilage, serum and chondrocytes of patients with LCPD, as well as dexamethasone (DEX)-exposed TC28 cells. Effects of exos-miR-214-3p on the proliferation and apoptosis were verified via MTT assay, TUNEL staining and caspase3 activity assay. The M2 macrophage markers were assessed by flow cytometry, RT-qPCR and Western blot. Moreover, angiogenic effects of human umbilical vein endothelial cells (HUVECs) were tested using CCK-8 and tube formation assays. Bioinformatics prediction, luciferase assay and ChIP were applied to verify the association between ATF7, RUNX1 and miR-214-3p.

RESULTS

miR-214-3p was found to be decreased in patients with LCPD and DEX-treated TC28 cells, of which overexpression promoted cell proliferation and suppressed apoptosis. Mechanistically, exos-miR-214-3p facilitated M2 polarization by ATF7/TLR4 axis and HUVECs angiogenesis via RUNX1/VEGFA axis.

CONCLUSION

miR-214-3p alleviates LCPD by promoting M2 polarization of macrophages and angiogenesis.

Do Weightbearing Restrictions Cause Excess Weight Gain in Children With LEGG-Calvé-Perthes Disease?

BACKGROUND

Restricted weight bearing is commonly prescribed in Legg-Calvé-Perthes Disease (LCPD), raising concerns of causing overweight or obesity. This study utilizes prospectively collected data to address the following questions: (1) does body mass index (BMI) Z-score increase over the course of LCPD follow-up; (2) is having a BMI category of normal, overweight, or obese at baseline associated with BMI Z-score changes over the course of follow-up; and (3) is the duration of weight bearing restrictions (no restrictions, <3, 3 to <6, 6 to 9, or >9 mo) associated with BMI Z-score changes.

METHODS

Data of 130 children aged 5 to 12 years with unilateral early-stage LCPD were extracted from an international database. Nation-specific BMI Z-scores and percentile-based weight categories were determined, and the duration of follow-up and weight bearing restrictions were calculated. Longitudinal changes in BMI Z-scores were evaluated for the 3 study questions using mixed effects linear regression models with surgery as a covariate. Sensitivity analyses were used to determine the influence of socio-cultural background (USA vs. India) for each study question.

RESULTS

During the 35.5±15.9 months of follow-up, no statistically significant increase in BMI Z-scores was observed across the entire cohort, or following stratification by baseline weight categories or the duration of the weight bearing restriction. Sensitivity analyses indicated that patients in the USA had no change in their BMI Z-score. When stratified by weight categories, the normal weight of US children had a small increase in their BMI Z-score (0.005 per mo, 95% confidence interval: 0.0002, 0.009), but this was not seen in other BMI categories. The cohort of Indian children had a small but significant decrease in their BMI Z-score (-0.005/mo, 95% CI: -0.009, -0.0002). After stratification by weight categories, a small decrease of the BMI Z-score was observed only in the Indian overweight children (-0.016 per mo, 95% CI: -0.027, -0.005) and no other BMI category.

CONCLUSIONS

Weightbearing restrictions over the course of follow-up for our cohort of children with early-stage LCPD were not associated with clinically meaningful increases of BMI Z-scores. Weight gain is multi-factorial and probably not caused by weight bearing restrictions alone.

LEVEL OF EVIDENCE

III Diagnostic Study.

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.

Co-occurrence of Blount's disease and Legg-Calvé-Perthes disease: is obesity a factor?

Legg-Calvé-Perthes disease (LCPD) and Blount's disease share a similar presenting age in addition to similar symptoms such as limp or knee pain. A little overlap is mentioned about both diseases. We sought to present cases of children having both conditions to discuss the implications of this co-occurrence on diagnosis and management. After institutional review board approval, we retrospectively reviewed records of four children who developed both Blount's disease and LCPD. Patient details and outcomes were analyzed. Radiographs were evaluated for the lateral pillar classification, Stulberg classification, tibial metaphyseal-diaphyseal angle and tibiofemoral angle. Two of the cases were initially diagnosed with Blount's disease and subsequently developed Perthes, one case presented initially with both disorders and the final case had Perthes followed by Blount's. Three children were obese and one was overweight. The common symptom to all patients was an abnormal gait, which was painless in two children and painful in two. Blount's disease required surgery in three children. Radiographs showed Lateral Pillar B, B/C border and C hips, and the final Stulberg was stage II (n = 2) or stage IV (n = 2). Obesity is associated with Blount's disease and LCPD, so obese children can be at an increased risk of developing both disorders. Therefore, a child with Blount's disease who has persistent, recurrent or worsening symptoms such as gait disturbance or thigh or knee pain might benefit from a careful physical exam of the hips to prevent a delayed or even missed LCPD diagnosis.

No increased mortality after total hip arthroplasty in patients with a history of pediatric hip disease: a matched, population-based cohort study on 4,043 patients

Background and purpose - Patients with pediatric hip diseases are more comorbid than the general population and at risk of premature, secondary osteoarthritis, often leading to total hip arthroplasty (THA). We investigated whether THA confers an increased mortality in this cohort.Patients and methods - We identified 4,043 patients with a history of Legg-Calvé-Perthes disease (LCPD), slipped capital femoral epiphysis (SCFE), or developmental dysplasia of the hip (DDH) in the Swedish Hip Arthroplasty Register (SHAR) between 1992 and 2012. For each patient, we matched 5 controls from the general population for age, sex, and place of residence, and acquired information on all participants' socioeconomic background and comorbidities. Mortality after THA was estimated according to Kaplan-Meier, and Cox proportional hazard models were fitted to estimate adjusted hazard ratios (HRs) for the risk of death.Results - Compared with unexposed individuals, patients exposed to a THA due to pediatric hip disease had lower incomes, lower educational levels, and a higher degree of comorbidity but a statistically non-significant attenuation of 90-day mortality (HR 0.9; 95% CI 0.4-2.0) and a lower risk of overall mortality (HR 0.8; CI 0.7-0.9).Interpretation - Patients exposed to THA due to a history of pediatric hip disease have a slightly lower mortality than unexposed individuals. THA seems not to confer increased mortality risks, even in these specific patients with numerous risk factors.

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.

Feasibility of Magnetic Resonance Angiography in Patients With Legg-Calvé-Perthes Disease

BACKGROUND

The etiology of Legg-Calvé-Perthes disease (LCPD) remains unknown; however, interruption of medial circumflex femoral artery (MCFA) supply to the femoral head is the key pathogenic factor. The main purpose of this study is to determine the feasibility of using magnetic resonance angiography (MRA) to evaluate the course of the MCFA in the normal and affected hips of patients with unilateral LCPD.

METHODS

We analyzed 24 patients with unilateral LCPD using a time-resolved imaging of contrast kinetics magnetic resonance angiography (TRICKS-MRA). The course of the MCFA was divided into 4 segments in the coronal plane and in 3 segments in the axial plane, based on its location with respect to the femoral neck. The visibility of each segment was studied in the normal and affected sides. The segments were defined as not visible when no contrast was seen within the vessel lumen or visible when the lumen was partially or completely visualized with contrast. The statistical analysis was done using the χ2 test.

RESULTS

TRICKS-MRA provided well-defined images of the first 2 segments of the MCFA on both the normal and affected sides of patients with LCPD (P=1). In half of the patients, the third segment was also visible using TRICKS-MRA on both sides (P=1). The fourth segment of the MCFA, which was the ascending lateral epiphyseal segment, was not visible on either side (P=0.49). No significant difference was found between the normal and affected hips in terms of visibility of the 4 segments of the MCFA using TRICKS-MRA. Anastomosis of the MCFA with the inferior gluteal artery was found in 3 hips (2 hips with LCPD and 1 normal hip).

CONCLUSIONS

TRICKS-MRA provides well-defined images of the arterial supply to the proximal femoral epiphysis in children with LCPD, presenting a noninvasive and radiation-free alternative to conventional angiography. However, the TRICKS-MRA method used did not allow visualization of the ascending lateral epiphyseal segment of MCFA in the affected and the contralateral normal side. We believe that further advancement of this noninvasive imaging technique may open new opportunities for research aimed at evaluating the vascular supply of the femoral head in children.

LEVEL OF EVIDENCE

Level IV-case-control study.

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.

Multiple occurrence of premature polyarticular osteoarthritis in an early medieval Bohemian cemetery (Prague, Czech Republic)

OBJECTIVES

To highlight conditions that may cause early-onset degenerative joint disease, and to assess the possible impact of such diseases upon everyday life.

MATERIAL

Four adults aged under 50 years from a medieval skeletal collection of Prague (Czechia).

METHODS

Visual, osteometric, X-ray, and histological examinations, stable isotope analysis of bone collagen.

RESULTS

All four individuals showed multiple symmetrical degenerative changes, affecting the majority of joints of the postcranial skeleton. Associated dysplastic deformities were observed in all individuals, including bilateral hip dysplasia (n = 1), flattening of the femoral condyles (n = 3), and substantial deformation of the elbows (n = 3). The diet of the affected individuals differed from the contemporary population sample.

CONCLUSIONS

We propose the diagnosis of a mild form of skeletal dysplasia in these four individuals, with multiple epiphyseal dysplasia or type-II collagenopathy linked to premature osteoarthritis as the most probable causes.

SIGNIFICANCE

Combining the skeletal findings with information from the medical literature, this paper defines several characteristic traits which may assist with the diagnosis of skeletal dysplasia in the archaeological record.

LIMITATIONS

As no genetic analysis was performed to confirm the possible kinship of the individuals, it is not possible to definitively assess whether the individuals suffered from the same hereditary condition or from different forms of skeletal dysplasia.

SUGGESTIONS FOR FURTHER RESEARCH

Further studies on premature osteoarthritis in archaeological skeletal series are needed to correct the underrepresentation of these mild forms of dysplasia in past populations.