Racial and geographic factors in the incidence of Legg-Calvé-Perthes' disease: a systematic review

Testing the Digital Atlas of Ancient Rare Diseases (DAARD) using a new case of Legg-Calvé-Perthes disease from Early Byzantine (500-700 CE) Olympia, Greece

OBJECTIVE

The first case of Legg-Calvé-Perthes disease (LCPD) in Greece is presented. LCPD, a rare disease, is discussed using the Digital Atlas of Ancient Rare Diseases (DAARD), which tests the benefits of the database for diagnosing and contextualizing the new case with 42 archaeological cases of LCPD recorded in the DAARD.

MATERIALS

A 30-40-year-old, probable male individual was found at the archaeological site of Olympia, Greece, dating to 500-700 CE.

METHODS

Biological sex, age-at-death and pathological changes were investigated using macroscopic and osteometric methods. The DAARD provided the typical characteristics of LCPD.

RESULTS

Pathological changes in both hip joints without any other related changes in the skeleton corresponded to the skeletal features of LCPD. The DAARD produced 42 cases of LCPD, most of which from Europe, with a preference for male sex and unilateral involvement of the hip joint.

CONCLUSIONS

The DAARD aids in diagnosing rare diseases and interpreting new cases in the context of already known studies.

SIGNIFICANCE

This study shows that the DAARD has the potential to help researchers move beyond the level of single case studies and create a broader picture of the history of rare diseases.

LIMITATIONS

This paper focuses on the benefits of the DAARD in relation to LCPD but not all rare diseases have been included in the database.

SUGGESTIONS FOR FURTHER RESEARCH

More rare diseases from archaeological contexts should be added to the DAARD to create a base for the interpretation of their history and expand our understanding of rare diseases in the past.

Effectiveness of therapeutic methods for Legg-Calvé-Perthes disease according to staging, limits of conservative treatment: a systematic review with meta-analysis

Legg-Calvé-Perthes disease (LCPD) is known as a self-limiting pediatric orthopedic pathology that affects the hip due to ischemia with consequent aseptic avascular necrosis of the femoral head. This is a systematic literature review carried out in the databases indexed in the Medical Literature Analysis and Retrieval System Online (MEDLINE) in accordance with the precepts established by the PRISMA methodology (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). The aim was to compare the effectiveness of treatment for Legg-Calvé-Perthes disease in relation to its staging: the limits of conservative treatment. Conservative treatment was used in four studies, and most patients under the age of 6.5 had Stulberg I and II results. Older patients, between eight and ten years old, had a relatively better classification when they underwent surgical treatment. In this context, the data collected did not show significant variations; however, it was possible to observe that conservative treatment was more effective in this population, while surgical treatment is better recommended at older ages.

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.

Epidemiology, natural evolution, pathogenesis, clinical spectrum, and management of Legg-Calvé-Perthes

Background

Legg-Calvé-Perthes disease is a self-limiting disorder that develops in children following interruption of the blood supply to the capital femoral epiphysis. This review outlines the current knowledge on the epidemiology, natural evolution, clinical spectrum, and management of the disease.

Methods

The literature pertaining to these aspects of the disease were studied and summarized in this review.

Results

Epidemiological studies suggest that environmental factors contribute to the causation of the disease. Incidence rates monitored over time indicate that the incidence of Legg-Calvé-Perthes disease is declining. The natural evolution followed on sequential plain radiographs enables division of the disease into Stages Ia, Ib, IIa, IIb, IIIa, IIIb, and IV. Reversible deformation of the capital occurs in Stages Ia-IIa simply on standing while irreversible deformation may occur in Stages IIb and IIIa. Treatment of Legg-Calvé-Perthes disease in Stages Ia-IIa aims to prevent the femoral head from getting deformed by containment and avoidance of weight-bearing. In Stages IIb and IIIa, treatment aims to remedy the effects of early irreversible deformation of the femoral head. In Stage IIIb and IV, treatment is directed to correcting the altered shape of the femoral head. The impression that these treatment methods are helpful is based on poor quality evidence.

Conclusion

There is an urgent need to undertake Level I studies to establish the efficacy of currently treatment.

Level of evidence

level V.

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.

Mid-term results of sub-trochanteric valgus osteotomy for symptomatic late stages Legg-Calvé-Perthes disease

BACKGROUND

The treatment of late stages of Legg-Calvé-Perthes disease (LCPD) is controversial. Although the concept of femoral head containment is a well-established technique of treatment, its use remains debatable in the late stages of the disease, as it does not improve symptoms in terms of limb length discrepancy and gait.

AIM

To assess the results of subtrochanteric valgus osteotomy in symptomatic patients with late-stage Perthes disease.

METHODS

From 2000 to 2007, 36 symptomatic patients with late stage of Perthes disease were surgically treated with subtrochanteric valgus osteotomy and followed-up for 8 to 11 years using the IOWA score and range of motion (ROM) variables. The Mose classification was also assessed at the last follow-up to reflect possible remodeling. The patients were 8 years old or older at the time of surgery, in the post-fragmentation stage, and complaining of pain, limited ROM, Trendelenburg gait, and/or abductor weakness.

RESULTS

The preoperative IOWA score (average: 53.3) markedly improved at the 1-year post follow-up period (average: 85.41) and then slightly improved at the last follow-up (average: 89.4) (P value < 0.05). ROM improved, with internal rotation increased on average by 22° (from 10° preoperatively to 32° postoperatively) and abduction increased on average by 15.9° (from 25° preoperatively to 41° postoperatively). The mean Mose deviation of femoral heads was 4.1 mm at the end of the follow-up period. The tests used were the paired t-test and Pearson correlation test, where the level of significance was a P value less than 0.05.

CONCLUSION

Subtrochanteric valgus osteotomy can be a good option for symptomatic relief in patients with late-stage of LCPD.

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.

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.

The British Orthopaedic Surgery Surveillance study: Perthes' disease: the epidemiology and two-year outcomes from a prospective cohort in Great Britain

Aims

The aim of this study was to evaluate the epidemiology and treatment of Perthes’ disease of the hip.

Methods

This was an anonymized comprehensive cohort study of Perthes’ disease, with a nested consented cohort. A total of 143 of 144 hospitals treating children’s hip disease in the UK participated over an 18-month period. Cases were cross-checked using a secondary independent reporting network of trainee surgeons to minimize those missing. Clinician-reported outcomes were collected until two years. Patient-reported outcome measures (PROMs) were collected for a subset of participants.

Results

Overall, 371 children (396 hips) were newly affected by Perthes’ disease arising from 63 hospitals, with a median of two patients (interquartile range 1.0 to 5.5) per hospital. The annual incidence was 2.48 patients (95% confidence interval (CI) 2.20 to 2.76) per 100,000 zero- to 14-year-olds. Of these, 117 hips (36.4%) were treated surgically. There was considerable variation in the treatment strategy, and an optimized decision tree identified joint stiffness and age above eight years as the key determinants for containment surgery. A total of 348 hips (88.5%) had outcomes to two years, of which 227 were in the late reossification stage for which a hip shape outcome (Stulberg grade) was assigned. The independent predictors of a poorer radiological outcome were female sex (odds ratio (OR) 2.27 (95% CI 1.19 to 4.35)), age above six years (OR 2.62 (95% CI (1.30 to 5.28)), and over 50% radiological collapse at inclusion (OR 2.19 (95% CI 0.99 to 4.83)). Surgery had no effect on radiological outcomes (OR 1.03 (95% CI 0.55 to 1.96)). PROMs indicated the marked effect of the disease on the child, which persisted at two years.

Conclusion

Despite the frequency of containment surgery, we found no evidence of improved outcomes. There appears to be a sufficient case volume and community equipoise among surgeons to embark on a randomized clinical trial to definitively investigate the effectiveness of containment surgery.

Cite this article: Bone Joint J 2022;104-B(4):510–518.

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.

The Natural History of Non-operatively Managed Legg-Calvé-Perthes' Disease

BACKGROUND

The purpose of this study was to examine the evolution of Legg-Calvé-Perthes' disease (LCPD) among children from British Columbia (BC), Canada who were treated non-operatively and to compare the results to a previously conducted study in India.

METHODS

This was a retrospective review of patients treated non-operatively for LCPD in BC between 1990 and 2006 compared with a cohort from India. Demographic and treatment information were collected from medical records. Radiographs were assigned modified Waldenstrom, Catterall, Salter-Thompson and Herring classifications and intra- and interobserver reliability were assessed. We evaluated epiphyseal extrusion (EE) and metaphyseal width (MW), and assessed radiographs using the Mose and modified Stulberg classifications.

RESULTS

102 hips (90 patients) had radiographs available for evaluation. 95% of the BC cohort presented as Waldenstrom stages I and II, whereas, 90% of the Indian cohort presented as IIIa. Final EE was similar for both groups (BC 26.8%, India 27.3%) and final MW was 119% in both groups. Modified Waldenstrom and Herring classifications had substantial intra- and interobserver reliability, while Salter-Thompson and Catterall classifications had moderate agreement at best. Most hips were Catterall IV (80%) and Herring C (89%) for the BC cohort compared to only 44% and 43% of Indian hips, respectively. Most hips were irregular according to the Mose classification (BC 43%, India 52%) and aspherical according to the Stulberg classification (BC 78%).

CONCLUSIONS

We found similar radiographic progression and final radiographic appearances of LCPD in India and BC though differences in the distribution of the classification systems warrant further study.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-021-00543-x.

Contrast-enhanced ultrasound for musculoskeletal indications in children

The increasing use of contrast-enhanced ultrasound (CEUS) has opened exciting new frontiers for musculoskeletal applications in adults and children. The most common musculoskeletal-related CEUS applications in adults are for detecting inflammatory joint diseases, imaging skeletal muscles and tendon perfusion, imaging postoperative viability of osseous and osseocutaneous tissue flaps, and evaluating the malignant potential of soft-tissue masses. Pediatric musculoskeletal-related CEUS has been applied for imaging juvenile idiopathic arthritis and Legg-Calvé-Perthes disease and for evaluating femoral head perfusion following surgical hip reduction in children with developmental hip dysplasia. CEUS can improve visualization of the capillary network in superficial and deep tissues and also in states of slow- or low-volume blood flow. In addition, measurements of blood flow imaging parameters performed by quantitative CEUS are valuable when monitoring the outcome of treatment interventions. In this review article we present current experience regarding a wide range of CEUS applications in musculoskeletal conditions in adults and children, with emphasis on the latter, and discuss imaging techniques and CEUS findings in musculoskeletal applications.

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.

Surgical Treatments for Legg-Calvé-Perthes Disease: Comprehensive Review

Background

Legg-Calvé-Perthes disease (LCPD) is a common public health problem that usually occurs between the ages of 4 and 8 years, but it can occur between the ages of 2 and 15 years. This condition occurs due to the interruption of blood supply to the femoral head. Up to now, different surgical and nonsurgical treatments, including femoral varus osteotomy, innominate osteotomy, pelvic osteotomies, triple osteotomy, Chiari osteotomy, and shelf acetabuloplasty, have been suggested for noncontainable LCPD hips.

Objective

The aim of this comprehensive review was to investigate the various surgical techniques used for LCPD.

Methods

An advanced electronic search of the English-language literature was performed from October 8 to 14, 2020. The electronic databases PubMed, MEDLINE, Web of Science, Embase, Ovid, and Google scholar were searched using appropriate search terms. A manual search of references also was performed. After retrieving the studies, duplicates were removed, and the remining studies were screened based on the title, abstract, and full text. The quality of the selected articles was assessed, and the required data were extracted from eligible articles.

Results

A total of 22 studies were included in the review. Based on the results of the reviewed studies, there are three main factors that influence the treatment outcomes in patients with Perthes disease. These factors are onset age, femoral head involvement severity, and treatment method. The disease has a poor prognosis in children over 8 years old, but this group of patients can also benefit from advanced surgical methods. In patients aged less than 6 years, the disease has a generally good prognosis, but in those aged between 6 and 8 years, its prognosis is variable. Thus, the need for surgical intervention requires close observation of signs. Once any head signs are observed, dynamic arthrography is beneficial before choosing the treatment approach.

Conclusions

This review provides clinicians with a brief guideline for the treatment of patients with LCPD.

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.

Global differences in the treatment of Legg-Calvé-Perthes disease: a comprehensive review

INTRODUCTION

Global discussions regarding the treatment of Legg-Calvé-Perthes disease (LCPD) are still controversial. The aim of this study was to characterize the worldwide regional differences in nonoperative and operative treatment for LCPD.

MATERIALS AND METHODS

Based on a comprehensive literature search, 123 studies describing the results of nonoperative and operative treatment for LCPD were included. Overall, disease and outcome parameters of 6,968 hips were recorded and compared among the continents-Europe, North America, Asia, Africa, South America, and Australia.

RESULTS

Our results showed that the continents differed regarding initial disease progression and therapeutic decision-making, but the final outcome was comparable. The reported proportion of affected hips with mild presentation tended to be higher in Europe, North America, and Africa, whereas disease progression was more severe in Asia, Australia, and South America. Nonoperative treatment was reported more frequently in Europe and North America, while operative management was more common in the rest of the world. Femoral osteotomy was performed more frequently than pelvic osteotomy worldwide, but pelvic osteotomy was comparably more common in North America, Australia, and South America.

CONCLUSIONS

The continents differed in terms of therapies for LCPD, while the final outcome was similar. Studies with greater evidence and larger sample size are needed to evaluate the effect of therapeutic measures on LCPD outcome.

LEVEL OF EVIDENCE

III (systematic review of level III studies).

The diagnosis and management of common childhood orthopedic disorders: An update

Musculoskeletal illness represents a significant portion of office visits to primary and urgent care clinicians. Despite this, little emphasis is placed on learning pediatric orthopaedics during medical school or residency. The focus of this paper is to provide a systematic approach to this general musculoskeletal physical exam and to assist in the recognition of what conditions are normal development and what conditions require observation, workup and referral to an experienced pediatric orthopaedist.

The outcomes of Perthes' disease

AIMS

To identify a suite of the key physical, emotional, and social outcomes to be employed in clinical practice and research concerning Perthes' disease in children.

METHODS

The study follows the guidelines of the COMET-Initiative (Core Outcome Measures in Effectiveness Trials). A systematic review of the literature was performed to identify a list of outcomes reported in previous studies, which was supplemented by a qualitative study exploring the experiences of families affected by Perthes' disease. Collectively, these outcomes formed the basis of a Delphi survey (two rounds), where 18 patients with Perthes' disease, 46 parents, and 36 orthopaedic surgeons rated each outcome for importance. The International Perthes Study Group (IPSG) (Dallas, Texas, USA (October 2018)) discussed outcomes that failed to reach any consensus (either 'in' or 'out') before a final consensus meeting with representatives of surgeons, patients, and parents.

RESULTS

In total, 23 different outcome domains were identified from the systematic review, and a further ten from qualitative interviews. After round one of the Delphi survey, participants suggested five further outcome domains. A total of 38 outcomes were scored in round two of the Delphi. Among these, 16 outcomes were scored over the prespecified 70% threshold for importance (divided into six main categories: adverse events; life impact; resource use; pathophysiological manifestations; death; and technical considerations). Following the final consensus meeting, 14 outcomes were included in the final Core Outcome Set (COS).

CONCLUSION

Core Outcome Sets (COSs) are important to improve standardization of outcomes in clinical research and to aid communication between patients, clinicians, and funding bodies. The results of this study should be a catalyst to develop high-quality clinical research in order to determine the optimal treatments for children with Perthes' disease. Cite this article: Bone Joint J 2020;102-B(5):611-617.

Risk factors during pregnancy and delivery for the development of Perthes' disease, a nationwide Swedish study of 2.1 million individuals

Background

To ascertain or disprove a correlation between suboptimal birth characteristics, breech position at delivery and development of Perthes’ disease.

Methods

Study material was collected from nationwide registers regarding diagnoses, birth statistics and delivery data. As study population were included children with a diagnosis code for Perthes’ disease who were alive and living in Sweden at age 13. Children with missing birth statistics were excluded. All children with no Perthes’ disease diagnosis were used as control group. Both single and multiple logistical regression analyses were used to calculate OR for the included characteristics.

Results

Children in breech position had a higher risk for developing Perthes’ disease. Children with Perthes’ disease had also a higher probability of having been born pre-term, very pre-term or post-term. Lower than normal birth weight and a lower Apgar-score were also associated with Perthes’ disease.

Conclusions

There is a correlation between breech birth and development of Perthes’ disease. There is also correlation to suboptimal birth characteristics. Despite our findings this should not be used for screening of Perthes’ disease as the percentage of children who actually develop it is very low. Also, as of yet there is no possibility to diagnose Perthes’ disease before the presence of skeletal changes. Our findings could be important in finding the cause of Perthes’ disease and therefore developing better diagnostics, treatment and prevention.

A not to be missed cause in a child with atraumatic limp

Children with musculoskeletal symptoms are commonly seen by general practitioners (GPs). Those that present with atraumatic limp pose a particular diagnostic challenge. Although uncommon, Perthes disease (PD) is an important cause of atraumatic limp in children and may result in debilitating consequences if missed. We put forward a case of delayed diagnosis of PD in a child, thus highlighting the need for a greater index of suspicion among GPs in approaching any child with a limp.

Perspectives on the Social, Physical, and Emotional Impact of Living With Perthes' Disease in Children and Their Family: A Mixed Methods Study

Aim. To determine the social, physical, and emotional impact of living with Perthes’ disease on affected children and their family (caregivers). Patients and Methods. Through a mixed methods approach, we interviewed 18 parents and explored the perspectives of 12 children affected by Perthes’ disease (mean = 7.1 years, SD = ±4.1 years) using a survey tool. Thematic analysis of parents’ interviews provided an insight into disease-specific factors influencing patients and family’s daily life activities. Using the childhood survey tool, good and bad day scores were analyzed using MANOVA (multivariate analysis of variance). Results. Thematic analysis of the parent interviews (main themes n = 4) identified a marked effect of the disease on many facets of the child’s life, particularly pain and the impact on sleep, play, and school attendance. In addition, the interviews identified a negative effect on the family life of the parents and siblings. Children indicated that activities of daily living were affected even during “good days” (P < .05), but pain was the key limiting factor. Conclusion. Perthes’ disease negatively affects the social, physical, and emotional well-being of children and their family. These findings provide outcome domains that are important to measure in day-to-day care and add in-depth insight into the challenges caused by this disease for health care professionals involved in clinical management.

Agreement of radiographic measurements and patient-reported outcome in 61 patients with Legg-Calvé-Perthes disease at mean follow-up of 28 years

It is unclear how patient-reported outcome in patients with Legg-Calvé-Perthes disease (LCPD) is correlated with radiographic outcome. It was therefore the aim of our long-term follow-up to evaluate the agreement of patient-reported outcome measures (PROM) with radiographic outcome in patients with a history of unilateral LCPD and a femoral head involvement of more than 50%. We further investigated to what extent the functional outcome (range of motion and Trendelenburg sign) correlates with PROM and radiographic outcome. At a mean follow-up of 28 years (15-42), 61 patients were investigated clinically and by plain radiography to evaluate the sphericity deviation score, femoral head enlargement and femoral neck growth inhibition. The patients also completed questionnaires for generic measures of health-related quality-of-life (ED-5D, EQ-visual analogue scale), the joint-specific Harris hip score and the nonarthritic hip score questionnaire. The radiographic measures sphericity deviation score, femoral head enlargement and femoral neck growth inhibition were strongly correlated with the joint-specific PROMs (Harris hip score and nonarthritic hip score) but not with EQ-5D and EQ-visual analogue scale. Inferior range of flexion and abduction and a positive Trendelenburg sign were associated with an inferior patient-reported outcome. Our findings highlight the importance of supporting femoral head re-modelling and containment and balancing trochanteric and femoral neck growth in patients with LCPD. To capture the whole picture of the outcome after LCPD, future studies should include a combination of radiographic measurements and joint-specific and generic outcome scores. Level of Evidence: Level III.

Association of eNOS 27-bp VNTR, 894G>T and 786T>C polymorphisms with susceptibility to Legg-Calve-Perthes Disease in Iranian children

Background

The aim of this study was to analyze the association of eNOS polymorphisms with risk of Legg-Calve-Perthes Disease (LCPD).

Methods

The study comprised of 45 LCPD patients and 55 controls. The eNOS polymorphisms were genotyped with PCR and by PCR-RFLP.

Results

The eNOS 894G > T and -786T > C polymorphisms were significantly associated with an increased risk of LCPD. However, there was no significant association between eNOS 27-bp VNTR polymorphism and LCPD risk.

Conclusion

Our results suggest that the eNOS 894G > T and -786T > C polymorphisms may be a risk factor for LCPD in Iranian children, but not 27-bp VNTR polymorphism.

What are the Demographics and Epidemiology of Legg-Calvé-Perthes Disease in a Large Southern California Integrated Health System?

BACKGROUND

Although many authors have reported the incidence of Legg-Calvé-Perthes disease (LCPD), there have been few incidence studies in the United States on large, self-contained populations such as those within an integrated health system. Understanding the epidemiology and demographics of LCPD in this setting may help clinicians identify patients at the greatest risk and aid in diagnosis and subsequent treatment.

QUESTIONS/PURPOSES

In this study we sought (1) to determine the incidence and demographics of LCPD in a large cohort of children and adolescents in a Southern California integrated healthcare system, and (2) to identify any demographic or clinical factors (such as age, sex, race/ethnicity, or BMI) that are independently associated with LCPD.

METHODS

A retrospective chart analysis was done on patients diagnosed with LCPD within our integrated healthcare system in patients aged 2 to 12 years over a 3-year period between 2010-2012. There were nearly 800,000 children in this cohort. Patient demographics were recorded; the incidence of LCPD was determined for the entire group and by sex, age, and race/ethnicity. Odds ratios for an association with LCPD based on age, sex, BMI and race/ethnicity were determined using logistic regression models.

RESULTS

The LCPD incidence per 100,000 for all children was 2.84, with the highest incidence in 2- to 5-year-old children (3.05; 95% CI, 1.51-4.59) and the lowest in 9- to 12-year-old children (1.06; 95% CI, 0.21-1.91). Incidence varied markedly among ethnicities, with the highest incidence in whites (5.69; 95% CI, 3.13-8.24) and the lowest in Asians (0.78; 95% CI, 0.00-2.32). Data analysis revealed a 3.13-times increased odds ratio (OR) of LCPD in 2- to 5-year-old patients versus 9- to 12-year-olds (p = 0.011), and boys had a 12.44 times greater OR of LCPD than girls (p < 0.001). Data analysis showed an increased OR for LCPD (3.41; 95% CI, 1.28-9.09) in patients with extreme obesity (BMI-for-age ≥ 1.2 × 95th percentile or a BMI ≥ 35 kg/m) compared with patients with a normal BMI.

CONCLUSIONS

Our study of a large integrated healthcare system in Southern California revealed an increased association of male sex and young age (2 to 5 years old) with LCPD. The overall incidence was lower overall than previously reported, although the incidence seen in white patients was similar to that in prior studies. The finding that patients with extreme obesity may have an increased association with LCPD merits further study. These findings may increase providers' awareness of the risk of the disease in younger patients and in extremely obese patients, and it also merits further future investigation as to whether there is a cause or effect relationship between extreme obesity and LCPD.

LEVEL OF EVIDENCE

Level IV, prognostic study.

The Pathogenesis and Treatment of Legg-Calvé-Perthes Disease

Legg-Calvé-Perthes disease is a childhood hip condition in which the blood supply to the capital femoral epiphysis is interrupted, causing osteonecrosis and chondronecrosis that lead to progressive deformity of the femoral head and secondary degenerative osteoarthritis in later life. The etiology of Legg-Calvé-Perthes disease remains unclear, with both biological and mechanical factors playing important roles in the pathogenesis of the condition. The treatment of Legg-Calvé-Perthes disease remains controversial but is dependent on several salient factors, including the age at clinical onset, the extent of epiphyseal involvement, the stage of the disease, and the degree of femoral head deformity. The literature supports operative containment treatment in the early stage of disease. Such treatment has led to improved femoral head sphericity with better patient outcomes in multicenter prospective cohort studies. The number of hips that need to be treated operatively in order to achieve a modest treatment effect remains high. Multicenter prospective cohort studies have shown that 6 to 7 patients need to be managed to create 1 spherical femoral head that would not have otherwise occurred.

Association of MTHFR and TNF-α genes polymorphisms with susceptibility to Legg-Calve-Perthes disease in Iranian children: A case-control study

Objective

The aim of this study was to assess the association of MTHFR and TNF-α genes polymorphisms with Legg-Calvé-Perthes' disease (LCPD) risk in the Iranian children.

Methods

A total of 45 children with LCPD and 55 healthy controls were recruited to the study. Genotyping was performed via the RFLP-PCR method and genetic risk was calculated by odds ratio (OR) with its corresponding 95% confidence interval (CI).

Results & conclusion

Our case-control study failed to determine any association of MTHFR (677C > T and 1298A > C) and TNF-α (-308G > A and -238G > A) polymorphisms with LCPD risk. More studies with larger sample size are warranted to validate our findings.

Outcomes in patients with late sequelae (healed stage) of Legg-Calvé-Perthes disease undergoing arthroscopic treatment: retrospective case series

INTRODUCTION

The residual hip deformities after Legg-Calvé-Perthes disease (LCPD) cause mechanical symptoms and are associated with a pathomechanical environment that can feature femoroacetabular impingement (FAI). The aim of this study is to evaluate the clinical and radiological outcomes in residual or healed LCPD after arthroscopic treatment.

PATIENTS AND METHODS

We retrospectively reviewed patients with LCPD amongst patients with FAI who underwent arthroscopic treatment between January 2009 and June 2013. We determined LCPD through 3-dimensional computed tomographic scans and simple radiography of the hip joint. The clinical outcomes were rated using a visual analogue scale pain score (VAS), the modified Harris Hip Score (mHHS) and hip range of motion (ROM) preoperatively and at the 2-year follow-up. All radiographs were assessed using the Tönnis classification system preoperatively and at the final follow-up of each patient. There were 23 patients (14 men, 9 women) with mean age 26.4 (range, 16-49) years undergoing arthroscopic treatment for FAI symptoms because of residual or healed LCPD.

RESULTS

At the 2-year follow-up, the mean VAS had improved significantly from 6.7 to 2.1, the mean mHHS had improved significantly from 62.6 to 87.4, and hip flexion and external rotation had improved significantly from 88.7° to 106.5° and from 20.4° to 33.5°, respectively (all p<0.001). The Tönnis osteoarthritis grade had not changed in any patient at the latest follow-up.

CONCLUSIONS

Arthroscopic treatment for sequelae of LCPD relieved symptoms and improved range of motion, making arthroscopic treatment a good option for the sequelae of LCPD.

Evaluation of femoral head viability via bone scintigraphy in the postoperative pediatric patient

BACKGROUND

Evaluating postoperative patients with hardware is challenging following surgical intervention for hip maladies such as femoral neck fractures and slipped capital femoral epiphysis (SCFE). These children are at increased risk of developing avascular necrosis, and imaging may be requested to confirm or exclude this diagnosis. Children with Legg-Calvé-Perthes disease can be monitored for restoration of blood flow to the capital femoral epiphysis to guide management and help with prognosis. Although MRI is sensitive for detecting early avascular necrosis, the presence of hardware degrades image quality.

OBJECTIVE

This report examines the utility of bone scans for evaluating femoral head perfusion in children who have undergone surgery for femoral neck fractures, SCFE or Legg-Calvé-Perthes disease.

MATERIALS AND METHODS

A retrospective review of 20 patients (22 scans) after fixation for femoral neck fracture, SCFE or Legg-Calvé-Perthes disease from 2012 to 2015 was performed. The bone scan findings were correlated with the intraoperative findings or clinical follow-up.

RESULTS

Twenty-one of the 22 (95%) bone scans in 19 of the 20 (95%) patients demonstrated findings consistent with clinical outcomes and/or the intraoperative appearance of the femoral head. Four of 20 patients (20%) had bone scan features of avascular necrosis, defined as "absent" or "moderately diminished" femoral head activity, which were confirmed intraoperatively and resulted in poor outcomes.

CONCLUSION

Radionuclide imaging of hips in the postoperative setting is a valuable modality for assessing the risk of avascular necrosis, a complication of femoral neck fractures and SCFE and for evaluating the restoration of flow to the capital femoral epiphyses of children with Legg-Calvé-Perthes disease.

The potential role of variations in juvenile hip geometry on the development of Legg-Calvé-Perthes disease: a biomechanical investigation

Legg-Calvé-Perthes disease (LCP) is one of the most poorly understood diseases in paediatric orthopaedics. One common trait of LCP is the marked morphological difference between healthy and pathological hips, early deviations of which (i.e. prior to disease onset) have been suggested to lead to the overload and collapse of the epiphysis. Here, the impact of common variations in geometry is investigated with a finite element model of a juvenile femur under single leg standing and landing. Here, the impact of typical variations in geometry is investigated with a finite element model of a juvenile femur under single leg standing and landing. The variations appear to have only a limited effect on the stress distribution in the femoral epiphysis even during high impact activities. This suggests that, for this individual at least, they would be unlikely to cause epiphyseal overload and collapse, even in the presence of a skeletally immature epiphysis.

A case control study to determine the association between Perthes' disease and the recalled use of tobacco during pregnancy, and biological markers of current tobacco smoke exposure

AIMS

It is well established that there is a strong association between Perthes' disease and worsening socioeconomic deprivation. It has been suggested that the primary determinant driving this association is exposure to tobacco smoke. This study aimed to examine this hypothesis.

PATIENTS AND METHODS

A hospital case-control study (n = 149/146) examined the association between tobacco smoke exposure and Perthes' disease, adjusting for area-level socioeconomic deprivation. Tobacco smoke exposure was assessed by parental questionnaire of smoking habits during pregnancy, and by quantitative assay of current exposure using the urinary cotinine-creatinine ratio, which is a widely used and validated measure of tobacco smoke exposure.

RESULTS

The odds of Perthes' disease significantly increased with reported in utero exposure after adjustment for socioeconomic deprivation (maternal smoking odds ratio (OR) 2.06, 95% confidence interval (CI) 1.17 to 3.63; paternal smoking OR 2.09, 95% CI 1.26 to 3.46). The cotinine-creatinine ratio was significantly greater in cases, OR 1.63 (95% CI 1.09 to 2.43), suggesting a greater 'dose' of current tobacco exposure.

CONCLUSION

An association exists between tobacco smoke exposure and Perthes' disease but we remain unable to disentangle the association with socioeconomic deprivation. Cite this article: Bone Joint J 2017;99-B:1102-8.

The Declining Incidence of Legg-Calve-Perthes' Disease in Northern Ireland: An Epidemiological Study

BACKGROUND

Legg-Calve-Perthes' disease (LCPD) is an idiopathic disease of the femoral head affecting the pediatric population. The causative factors remains poorly understood and it is associated with significant hip pathology in adult life. Research has demonstrated wide geographical variation in the incidence rates of LCPD with a relatively high incidence occurring in Northern Ireland (NI) shown in a previous study of incidence from the same unit. The number of new diagnoses of LCPD seems to be declining over time. This study aimed to track changes in the incidence of LCPD within the 0- to 14-year-old population over a 15-year period in NI.

METHODS

An established database was utilized to collate information of any individual between the ages of 0 to 14 years with a diagnosis of LCPD. The data were compared with electronic radiologic records to confirm the diagnosis. Postal code data were used to the determine location of residence and used as a proxy measure of deprivation.

RESULTS

The results of this epidemiological study have demonstrated a 61% decrease in the incidence of LCPD over a 15-year period within the pediatric population of NI. Comparison between 2 cohorts reveals no distinguishable change in distribution of age or sex. The relationship between geographical proxy measures of deprivation in NI and LCPD remains evident.

CONCLUSIONS

The number of new cases of LCPD is decreasing over time. The epidemiological data are unchanged between 2 cohorts over a 15-year period, and this therefore supports a change within the patients' environment relating to this decline. This change could relate to a number of factors including smoking rates, breastfeeding, lead use, and vaccination implementation.

LEVEL OF EVIDENCE

Level IV-retrospective cohort study.

The Demographics of Canine Hip Dysplasia in the United States and Canada

Canine hip dysplasia (CHD) is a common problem in veterinary medicine. We report the demographics of CHD using the entire hip dysplasia registry from the Orthopedic Foundation for Animals, analyzing differences by breed, sex, laterality, seasonal variation in birth, and latitude. There were 921,046 unique records. Each dog was classified using the American Kennel Club (AKC) and Fédération Cynologique Internationale (FCI) systems. Statistical analysis was performed with bivariate and logistic regression procedures. The overall CHD prevalence was 15.56%. The OR for CHD was higher in females (1.05), those born in spring (1.14) and winter (1.13), and those in more southern latitudes (OR 2.12). Within AKC groups, working dogs had the highest risk of CHD (OR 1.882) with hounds being the reference group. Within FCI groups, the pinscher/molossoid group had the highest risk of CHD (OR 4.168) with sighthounds being the reference group. The similarities between CHD and DDH are striking. Within DDH there are two different types, the typical infantile DDH and the late onset adolescent/adult acetabular dysplasia, with different demographics; the demographics of CHD are more similar to the later onset DDH group. Comparative studies of both disorders should lead to a better understanding of both CHD and DDH.

Alterations of serum osteocalcin levels in patients with Legg-Calvé-Perthes

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) is a paediatric form of osteonecrosis that ultimately heals but will cause femoral head and acetabular deformities. The purpose of this study was to investigate the early serum measurement of osteocalcin in children with femoral head necrosis compared with that of healthy children.

METHODS

20 patients with LCPD (4 girls and 16 boys) and 20 healthy volunteers (5 girls and 15 boys) were enrolled. All patients did not have additional treatment. Blood samples were obtained from all patients preoperatively in the morning. All cases had hip radiographs. The serum levels of osteocalcin comparisons between the LCPD patients and the healthy volunteers were performed using Wilcoxon signed-rank test. The Spearman rank correlation was used to assess correlation between LCPD grade and serum osteocalcin levels. Significance was set at p = 0.05.

RESULTS

The 20 patients with LCPD (72.75 ± 24.92 ng/ml) had significantly higher serum osteocalcin levels compared with the healthy group (16.80 ± 4.04 ng/ml) (p<0.01). Serum osteocalcin levels of different LCPD grades were significantly different (Spearman's p = 0.540, p = 0.014).

CONCLUSIONS

We observed a significant correlation between serum osteocalcin levels and LCPD. These results may be meaningful in clinical practice and to future studies.

Incidence of Perthes' disease in children born between 1973 and 1993

Background and purpose - The incidence of Perthes' disease as reported in the literature varies widely between and within countries. The etiology of the disease is still unknown. Both environmental and genetic factors have been suggested to play a part in either causing the disease or increasing the susceptibility of an individual. We determined the incidence of Perthes' disease in Sweden and investigated possible relationships to parental socioeconomic status, ethnicity, marital status, mothers' age when giving birth, parity, number of siblings, and smoking habits. Patients and methods - Six Swedish population-based registers were used, together covering all children born in Sweden from 1973 through 1993. Results - The incidence of Perthes' disease in Sweden was 9.3 per 100,000 subjects. The ratio between boys and girls was 3.1:1. The educational level of the father and the mother of a child with Perthes' disease was lower than in the controls. The incidence was lower when the fathers were in the highest income bracket (above the 90^th percentile). A higher proportion of parents of Nordic lineage had children with Perthes' disease than parental pairs with one or both who were not of such lineage. Interpretation - This study confirms that there is an association between the incidence of Perthes' disease and the socioeconomic status of the parents.

Protocol for a randomised control trial of bisphosphonate (zoledronic acid) treatment in childhood femoral head avascular necrosis due to Perthes disease

INTRODUCTION

Perthes disease (PD) is an idiopathic disorder presenting with avascular necrosis to the femoral head, which frequently results in flattening. Long-term function is directly related to the subsequent femoral head sphericity. Current treatment includes mechanical modalities and surgical procedures, which are therapeutic but are not uniformly able to prevent collapse. The use of the nitrogen-containing bisphosphonate zoledronic acid (ZA) to inhibit osteoclastic bone resorption is aimed at preserving femoral head strength, reducing collapse and thus maintaining shape. The proposed multicentre, prospective, randomised controlled trial intends to evaluate the efficacy of ZA treatment in PD.

METHODS AND ANALYSIS

An open-label randomised control trial recruiting 100 children (50 each treatment arm) 5 to 16 years old with unilateral PD. Subjects are randomly assigned to either (a) ZA and standard care or (b) Standard care. The primary outcome measure is deformity index (DI), a radiographic parameter of femoral head roundness assessed at 24 months, following 12 months of ZA treatment (3-monthly doses of ZA 0.025 mg/kg at baseline, 3, 6, 9 and 12 months) plus 12 months observation (group A) or 24 months of observation (group B). Secondary outcome measures are femoral head subluxation, Faces Pain scale, Harris hip score and quality of life. Assessments are made at baseline, 3 monthly during the first year of follow-up and then 6 monthly, until the 24th month.

ETHICS AND DISSEMINATION

The study commenced following the written approval from the Human Research Ethics Committee. Safety considerations regarding the effects of ZA are monitored which include the subject's symptomatology, mineral status, bone mass and turnover activity, and metaphyseal modelling. Data handling plan requires that all documents, clinical information, biological samples and investigation results will be held in strict confidence by study investigators to preserve its safety and confidentiality.

TRIAL REGISTRATION NUMBER

Australian and New Zealand Clinical Trials ACTRN12610000407099, pre-results.

Skeletal immaturity, rostral sparing, and disparate hip morphologies as biomechanical causes for Legg-Calvé-Perthes' disease

Legg-Calvé-Perthes' (Perthes') disease is a developmental disease of the hip joint that may result in numerous short and long term problems. The etiology of the disease remains largely unknown, but the mechanism is believed to be vascular and/or biomechanical in nature. There are several anatomical characteristics that tend to be prevalent in children with Perthes' disease, namely: skeletal immaturity, reduced height, and rostral sparing. We present an overview of the literature, summarizing the current understanding of the pathogenesis, particularly related to how the formation of the vasculature to the femoral epiphysis places children aged 5-8 at a higher risk for Perthes' disease, how skeletal immaturity and rostral sparing could increase the probability of developing Perthes' disease, and how animal models have aided our understanding of the disease. In doing so, we also explore why Perthes' disease is correlated to latitude, with populations at higher latitudes having higher incidence rates than populations closer to the Equator. Finally, we present five hypotheses detailing how Perthes' disease could have a biomechanical cause. Clin. Anat. 29:759-772, 2016. © 2016 Wiley Periodicals, Inc.

A Twin Study of Perthes Disease

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) is an idiopathic avascular necrosis of the femoral head. Its etiology is poorly understood, although previous studies have implicated low birth weight and possible genetic determinants. The aim of this study was to identify potential birth weight and genetic associations with LCPD.

METHODS

We extracted all twin pairs from the Danish Twin Registry (DTR) in which at least 1 individual had LCPD. The DTR captures every twin pair born alive in Denmark, and those with LCPD were identified by using health record linkage. Probanwise concordance was calculated to describe the likelihood that any given individual had LCPD if their co-twin was also diagnosed.

RESULTS

There were 81 twin pairs: 10 monozygotic, 51 dizygotic, and 20 unclassified (unknown zygosity [UZ]). There was no association between birth weight and being the affected co-twin. Four pairs (2 dizygotic and 2 UZ) were concordant for LCPD, which is greater than would be expected assuming no familial aggregation. There were no concordant monozygotic twin pairs. The overall probandwise concordance was 0.09 (95% confidence interval [CI]: 0.01-0.18): 0.00 for the monozygotic, 0.08 (95% CI: 0.00-0.18) for the dizygotic, and 0.18 (95% CI: 0.00-0.40) for the UZ twin pairs.

CONCLUSIONS

This study found evidence of familial clustering in LCPD but did not show a genetic component. The absolute risk that a co-twin of an affected individual will develop LCPD is low, even in the case of monozygotic twin pairs.

Epigenetics in Legg-Calvé-Perthes disease: A study of global DNA methylation

OBJECTIVE

To examine the global methylation status of DNA in blood cells of children with Legg-Calvé-Perthes disease (LCPD), since the aetiopathogenesis of LCPD remains unclear, and many factors closely associated with DNA methylation may be linked to the occurrence of LCPD.

METHODS

Children with LCPD and age-, sex- and body mass index-matched controls were evaluated. Methylation levels of the long interspersed nuclear element 1 (LINE-1), a biomarker of global DNA methylation, were quantified by methylation-specific polymerase chain reaction.

RESULTS

Of 82 children with LCPD (68 male/14 female) and 120 matched controls (98 male/22 female), methylation of the LINE-1 promoter was significantly lower in patients with LCPD compared with controls. Subgroup analyses showed that methylation of the LINE-1 promoter was significantly lower in male patients with LCPD compared with male controls. No significant between-group differences were observed in female participants.

CONCLUSIONS

Reduced global DNA methylation may be associated with increased risk of LCPD in male children. Further research is required to understand whether detection of global DNA methylation may provide a basis for clinical diagnosis and early intervention of LCPD.

Comparative study of serum proteomes in Legg-Calve-Perthes disease

Background

Legg-Calve-Perthes Disease (LCPD) is an idiopathic osteonecrosis of the developing femoral head complicated by pain and disability of the hip joint. To date, the pathological mechanisms of LCPD are not well-known. This study screened the changes in serum protein expression in patients with LCPD.

Methods

Age- and sex-matched serum samples from 10 control subjects and 10 patients with LCPD were compared using the isobaric tags for relative and absolute quantification (iTRAQ) technique. Gene ontology analyses, KEGG pathway and functional network analyses were performed. Proteins of interest with large differences in expression, S100-A8, alpha-1-acid glycoprotein 1, haptoglobin and apolipoprotein E, were compared by western blotting.

Results

The disease/control ratios showed 26 proteins were significantly differentially expressed (all p < 0.05). Including higher abundances of complement factor H (1.44), complement C4-B (1.45), isocitrate dehydrogenase [NAD] subunit alpha (2.7) alpha-1-acid glycoprotein 1 (1.87), heptoglobin (1.53) and Ig lambda-2 chain C regions (1.46), and lower levels of apolipoprotein E (0.50), apolipoprotein F (0.60), apolipoprotein C-III (0.69), S100-A8 (0.73), S100-A9 (0.75) and prothrombin (0.77) in LCPD than in controls. The alpha-1-acid glycoprotein 1 and haptoglobin increases, and apolipoprotein E and S100-A8 decreases were confirmed by western blot. KEGG pathway analysis revealed these proteins were related to the complement and coagulation cascades, Staphylococcus aureus infection, PPAR signaling, fat digestion and absorption, and vitamin digestion and absorption. Functional network analysis suggested that the proteins were involved in lipid regulation.

Conclusions

The complement and coagulation cascades, and abnormal lipid metabolism may be involved in the pathogenesis of LCPD.

Predictive genetic markers of coagulation, inflammation and apoptosis in Perthes disease—Serbian experience

Perthes disease is one of the most common forms of pediatric femoral head osteonecrosis with an unknown etiology. Coagulation factors were the first genetic factors suspected to have a role in the pathogenesis of this disease, but studies showed inconsistent results. It is described that inflammation is present during early stages of Perthes disease, but its genetic aspect has not been studied extensively. Little is known regarding the status of apoptotic factors during the repair process that leads to the occurrence of hip deformity in patients. Therefore, the aim of this study was to analyze major mediators involved in coagulation, inflammation, and apoptotic processes as possible causative factors of Perthes disease. The study cohort consisted of 37 patients. Gene variants of TNF-α, FV, FII, and MTHFR genes were determined by PCR-RFLP, while IL-3 and PAI-1 were genotyped by direct sequencing. The expression level of Bax, Bcl-2, Bcl2L12, Fas and FasL was analyzed by quantitative reverse-transcriptase polymerase chain reaction (qRT-PCR) technique. Our results showed a significantly increased level of expression of pro-apoptotic factor Bax along with significantly higher Bax/Bcl-2 ratio in the patient group.

CONCLUSION

The results presented indicate that apoptosis could be one of the factors contributing to the lack of balanced bone remodeling process in Perthes patients.

Avascular necrosis in pediatric systemic lupus erythematosus: a brief report and review of the literature

Avascular necrosis (AVN) occurs in several chronic illnesses, including systemic lupus erythematosus (SLE), but can also occur in healthy children. There are multiple theories to explain why and how AVN occurs, but an exact mechanism has yet to be unraveled. AVN in the pediatric lupus population is understudied. The Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial, provides an excellent venue to conduct an exploratory analysis to assess associations between AVN and demographics, SLE disease activity and vitamin D deficiency. Herein we present a brief report describing our findings, as well as reviewing the literature on AVN in SLE and other entities.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT00065806.

Interobserver and intraobserver reliability of the modified Waldenström classification system for staging of Legg-Calvé-Perthes disease

BACKGROUND

The absence of a reliable classification system for Legg-Calvé-Perthes disease has contributed to difficulty in establishing consistent management strategies and in interpreting outcome studies. The purpose of this study was to assess interobserver and intraobserver reliability of the modified Waldenström classification system among a large and diverse group of pediatric orthopaedic surgeons.

METHODS

Twenty surgeons independently completed the first two rounds of staging: two assessments of forty deidentified radiographs of patients with Legg-Calvé-Perthes disease in various stages. Ten of the twenty surgeons completed another two rounds of staging after the addition of a second pair of radiographs in sequence. Kappa values were calculated within and between each of the rounds.

RESULTS

Interobserver kappa values for the classification for surveys 1, 2, 3, and 4 were 0.81, 0.82, 0.76, and 0.80, respectively (with 0.61 to 0.80 considered substantial agreement and 0.81 to 1.0, nearly perfect agreement). Intraobserver agreement for the classification was an average of 0.88 (range, 0.77 to 0.96) between surveys 1 and 2 and an average of 0.87 (range, 0.81 to 0.94) between surveys 3 and 4.

CONCLUSIONS

The modified Waldenström classification system for staging of Legg-Calvé-Perthes disease demonstrated substantial to almost perfect agreement between and within observers across multiple rounds of study. In doing so, the results of this study provide a foundation for future validation studies, in which the classification stage will be associated with clinical outcomes.

The epidemiology of transient synovitis in Liverpool, UK

BACKGROUND

The epidemiology of transient synovitis is poorly understood, and the aetiology is unknown, although a suggestion of a viral association predominates.

PURPOSE

This population-based study investigated the epidemiology in order to formulate aetiological theories of pathogenesis.

PATIENT AND METHODS

Cases in Merseyside were identified between 2004 and 2009. Incidence rates were determined and analysed by age, sex, season and region of residence. Socioeconomic deprivation scores were generated using the Index of Multiple Deprivation, allocated by postcode. Poisson confidence intervals were calculated and Poisson regression was used to check for trends.

RESULTS

Two hundred and fifty-nine cases were identified over 5.5 years. The annual incidence was 25.1 (95 % CI 22.1-28.5) per 100,000 0-14 year-olds. Male to female ratio was 3.2:1 (p < 0.001). Mean age at presentation was 5.4 years (95 % CI 5.0-5.8), which demonstrated a near-normal distribution. No relationship was identified between seasonality and incidence (p = 0.64). A correlation was identified with socioeconomic deprivation in Merseyside: incidence rate ratio 1.16 (95 % CI 1.06-1.26, p < 0.001), although further analysis within the subregion of Liverpool did not confirm this finding (p = 0.35).

CONCLUSIONS

The normal distribution for age at disease presentation suggests a specific disease entity. The absence of seasonality casts some doubt on the popular theory of a viral aetiology. The absence of a consistent socioeconomic gradient in both Merseyside and Liverpool challenges a previous suggestion of an association with Perthes' disease. This paper provides ecological evidence that may challenge existing aetiological theories, though transient synovitis remains an enigma.

Female patients with late-onset legg-calvé-perthes disease are frequently gymnasts: is there a mechanical etiology for this subset of patients?

BACKGROUND

The cause of Legg-Calvé-Perthes disease (LCPD) is unknown. We have observed a relatively high prevalence of female gymnasts presenting with LCPD. The purpose of this study was to determine: (1) the percentage of LCPD patients exposed to high-level gymnastics training, (2) the demographics of this subset of patients, and (3) their clinical outcomes.

METHODS

Several adolescent female gymnasts presented to our clinic with recent-onset LCPD. We reviewed our cases to discern the prevalence and treatment of the disorder in this patient cohort. From 1999 to 2010, 572 patients were evaluated for a diagnosis of LCPD at our tertiary referral center. Clinical records were retrospectively reviewed. Of those, 13 patients had a history of gymnastics participation with 8 patients (all females) having competitive participation.

RESULTS

For females aged 10 years and older presenting with LCPD, 7 of 9 patients (78%) were involved in high-level competitive gymnastics. These patients had disease onset between 10 and 12 years of age (mean, 11 y). Competitive gymnasts represented 6.6% (8 of 120) of females with LCPD and 1.4% (8 of 572) of all patients evaluated with LCPD during the study period. Only 1 of 111 females below 10 years with LCPD participated in competitive gymnastics (χ, P<0.0001).Patients underwent a variety of treatments. Two patients underwent nonoperative treatment, and the remainder underwent surgical management. All 7 gymnasts had a Stulberg IV result. In the nongymnast group of females 10 years and older, there were 1 Stulberg III result and 1 Stulberg IV result.

CONCLUSIONS

At our center, competitive gymnasts comprise >75% of the female patients over the age of 10 who presented with late-onset LCPD. Results in general were poor. Further studies are needed to explore the association between the physical demands of advanced gymnastic training and the development of LCPD in this subset of patients.

LEVEL OF EVIDENCE

IV, case series.

Unravelling the enigma of Perthes disease

Perthes disease is an idiopathic avascular necrosis of a juvenile hip. Although 2010 marked a century since it was first described, the aetiology remains unknown. It is suggested that adverse socioeconomic circumstances may be a key precipitant. This work describes recent studies that explore the disease epidemiology. Descriptive studies include a case register from Merseyside, hospital discharge data from Scotland, analysis of the world's largest community disease register (General Practice Research Database [GPRD]) and a systematic review of incidence. Analytical studies include a nested case-controlled study in the GPRD and a hospital case-controlled study. The studies demonstrated a striking north-south divide in the UK incidence of Perthes disease, similar to that seen in many adult diseases. There was a sustained fall in disease frequency in all studies, with a narrowing of the north-south divide. There was a strong association with area deprivation, independent of living in an urban environment. Internationally, equatorial regions were unaffected by disease and northern Europe had the highest incidence, which was primarily a function of race although latitude was an independent predictor. Individual characteristics associated with the disease were congenital anomalies of the genitourinary tract and a structural abnormality of arterial calibre. Despite a falling incidence, Perthes disease remains an important cause of child morbidity and exemplifies socioeconomic inequalities. A deprivation-related exposure, acting early in development, appears critical. The aetiological factor in Perthes disease remains elusive but it is likely that unravelling this enigma may unlock additional secrets pertaining to the developmental origins of this and other diseases.