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

Risk Factors for Developing Perthes Disease: A Comprehensive National Analysis Spanning 2 Decades

BACKGROUND

Perthes disease is an uncommon pediatric condition affecting the hip joint, causing varying degrees of femoral head necrosis. The underlying cause of Perthes remains unknown, thus it is crucial to identify risk factors associated with its development to aid in early diagnosis and intervention. This study aimed to analyze risk factors associated with Perthes in a large cohort.

METHODS

A case-control study was conducted using data from a U.S. national database from 2003 to 2023. Patients diagnosed with Perthes were compared with those without the disease. Variables potentially associated with Perthes were analyzed using multivariable logit models, and adjusted odds ratios (AOR) with 95% CI were calculated. Statistical significance was determined, and a P -value <0.05 was considered significant.

RESULTS

The study included 4034 patients with Perthes and 3,483,745 age-matched controls. The mean age of patients with Perthes was 8.38 years, compared with 8.35 years in the control group ( P =0.27). Significant risk factors identified included male sex (AOR: 3.14, P <0.001), white race (AOR: 2.16, P <0.001), and obesity (AOR: 2.21, P <0.001). Conversely, Black (AOR: 0.26, P <0.001), Hispanic (AOR: 0.53, P <0.001), and Asian (AOR: 0.55, P <0.001) races were associated with lower odds of developing Perthes. Additional significant risk factors included tobacco exposure (AOR: 1.25, P =0.02), hypertension (AOR: 1.64, P <0.001), and thrombophilia (AOR: 9.17, P <0.001).

CONCLUSIONS

This study is the largest study on Perthes disease in literature, identifying several independent risk factors, including male sex, white race, obesity, tobacco exposure, hypertension, obesity, and thrombophilia. Among children with Perthes, thrombophilia exhibited the highest adjusted odds ratio, despite its rarity. These findings offer valuable insights for further research aimed at elucidating the underlying etiology of Perthes disease, particularly with regards to the roles of vascular and metabolic pathways.

LEVEL OF EVIDENCE

Level III-prognostic case-control study.

Incidence trends and risk factors for Perthes' disease in children born between 1985 and 2016 : a Danish nationwide register-based study

Aims

In this study, we aimed to evaluate incidence trends and potential risk factors associated with Perthes' disease in Denmark, using publicly available data.

Methods

Our population-based case-control study used data from the Danish National Patient Register and Danish Civil Registration System, accessed through the publicly available Danish Biobank Register, to identify 1,924,292 infants born between 1985 and 2016. We estimated age-specific incidence rates for four birth periods of equal duration (1985 to 1992, 1993 to 2000, 2001 to 2008, and 2009 to 2016) and investigated associations with perinatal conditions, congenital malformations, coagulation defects, autism spectrum disorders (ASD), and attention deficit hyperactivity disorders (ADHD).

Results

We identified 2,374 (81.6% male) diagnosed with Perthes' disease aged between two and 12 years, corresponding to an overall incidence of 12.1 per 100,000 live births relative to the year of birth. The incidence declined across all four birth periods, irrespective of sex or age at diagnosis. Several perinatal conditions were associated with higher Perthes' disease risk. Children with reported birth injuries (vs no reported injuries) exhibited the highest risk (relative risk (RR) 7.48 (95% CI 3.37 to 16.63)) followed by those with versus without coagulation defects (RR 4.77 (95% CI 1.79 to 12.69)). Children diagnosed with syndromic (RR 2.90 (95% CI 2.08 to 4.04)) or non-syndromic major congenital malformations (RR 1.86 (95% CI 1.55 to 2.23)) (vs those with no malformation diagnosis) were also associated with higher Perthes' disease risk. The development of Perthes' disease was positively associated with several ASD and ADHD diagnoses. However, once adjusting for the sex of the child and period of birth, the associations with ASD and ADHD were no longer significant.

Conclusion

Using publicly available data, we observed a declining incidence of Perthes' disease in Denmark over a 32-year study period. Our findings also confirm positive associations between Perthes' disease and various perinatal conditions, coagulation defects, and congenital malformations, highlighting potential aetiological pathways for further investigation.

No correlation to collagen synthesis disorders in patients with Perthes' disease: a nationwide Swedish register study of 3488 patients

BACKGROUND

Mutations of the COL2A1 gene have been identified in patients with Perthes' disease. Several studies have hypothesised a connection between Perthes' disease and collagen synthesis disorders, especially COL2A1-related disorders, but no large studies on the subject have been made. The aim of this study was thus to discover if there is a connection between patients presenting with Perthes' disease, and collagen synthesis disorders. A secondary aim was to see if the children with both disorders had less optimal birth characteristics than the rest.

METHODS

Swedish national registers were used to collect data on children diagnosed with Perthes' disease or a collagen synthesis disorder. These registers include all births in Sweden, and data from both outpatient and in-hospital visits. A wide range of data is included besides diagnoses. All children with follow-up data to the age of 15 years were included. Pearson's chi-square was used for analysis. Statistical significance was further analysed with Fisher's Exact Test.

RESULTS

In total, 3488 children with either diagnosis were included. 1620 children had only Perthes disease, while 1808 children had only a collagen synthesis disorder. Five children were found to have both the diagnosis Perthes' disease and a collagen synthesis disorder. One child was large for their gestational age and none of the children had a low birthweight. Two of the children were moderately preterm.

CONCLUSIONS

The distinct lack of overlap in such a large body of material raises doubt about a connection between the presentation of Perthes' disease and collagen synthesis disorders, either COL2A1-related or not. We could not find an overrepresentation of less optimal birth characteristics either.

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.

Could Subtle Obstetrical Brachial Plexus Palsy Be Related to Unilateral B Glenoid Osteoarthritis?

Background: Several factors associated with B glenoid are also linked with obstetrical brachial plexus palsy (OBPP). The purpose of this observational study was to determine the incidence of OBPP risk factors in type B patients. Methods: A cohort of 154 patients (68% men, 187 shoulders) aged 63 ± 17 years with type B glenoids completed a questionnaire comprising history of perinatal characteristics related to OBPP. A literature review was performed following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to estimate the incidence of OBPP risk factors in the general population. Results: Twenty-seven patients (18%) reported one or more perinatal OBPP risk factors, including shoulder dystocia (n = 4, 2.6%), macrosomia >4 kg (n = 5, 3.2%), breech delivery (n = 6, 3.9%), fetal distress (n = 8, 5.2%), maternal diabetes (n = 2, 1.3%), clavicular fracture (n = 2, 1.3%), and forceps delivery (n = 4, 2.6%). The comparison with the recent literature suggested that most perinatal OBPP risk factors were within the normal range, although the incidence of shoulder dystocia, forceps and vaginal breech deliveries exceeded the average rates. Conclusion: Perinatal factors related to OBPP did not occur in a higher frequency in patients with Walch type B OA compared to the general population, although some of them were in the high normal range.