The seasonality of slipped upper femoral epiphysis--meta-analysis: a possible association with vitamin D

Slipped Capital Femoral Epiphysis Pathogenesis and Its Relation to Obesity—Where Do We Stand? A Narrative Review

Slipped capital femoral epiphysis (SCFE) is the most common adolescent hip disorder in children 9–15 years old with an incidence that ranges from 0.33:100,000 to 24.58:100,000. Idiopathic SCFE is strongly associated with obesity, while atypical SCFE is associated with endocrinopathies, metabolic and renal disease, radiation therapy, and chemotherapy. In this review, we summarized the current data regarding the pathogenesis of SCFE and its association to obesity. In the last years, there have been increasing evidence regarding the implication of obesity in the pathogenesis of SCFE, but no definitive mechanism has been proven. The etiology is probably multifactorial, with both mechanical and metabolic factors contributing to the disease, with the later gaining more ground, especially in obese patients. Understanding what causes the disease will help paediatricians and orthopaedists develop more efficient strategies for treating patients and diminishing complication rates.

Is the level of vitamin D deficiency correlated with the severity and bilaterality in slipped capital femoral epiphysis? A case series study

The aim of the study is to find the correlation between vitamin D level and the severity of slippage and bilateral development in slipped capital femoral epiphysis (SCFE) cases if any. Thirty-nine patients with moderate-severe stable SCFE were evaluated regarding their vitamin D level and to which extent the severity of vitamin D deficiency, if present, can be correlated with the severity and bilaterality of the slip. Vitamin D serum level was assessed pre- operatively for all patients. In case of deficiency, the patient underwent in situ pinning unless performed before his/her presentation. Alongside, he/she received a vitamin D course until correction prior to the definitive surgery (Imhäuser osteotomy with osteochondroplasty) 6-12 weeks after. Thereafter, osteotomy healing and physis closure were monitored radiologically. Results show that all patients but one had vitamin D deficiency, with an average of 14.39 ng/mL, necessitating vitamin D therapy before proceeding to the definitive surgery. No correlation existed between vitamin D level and Southwick angle severity with a p-value of 0.85. A negative correlation existed between vitamin D level and bilaterality, but not statistically significant (p-value 0.192). Patients’ osteotomy healing was uneventful, and physeal closure was achieved in all the cases that had in situ pinning. We conclude that the severity of Vitamin D deficiency could be linked to the bilateral development of SCFE but not the severity of slippage. Treatment of Vitamin D deficiency facilitates physeal closure.

Effect of seasonal variation on the peak presentation of slipped capital femoral epiphysis. A comparison of children in Johannesburg, South Africa and London, UK

Variation exists in the peak presentation of slipped capital femoral epiphysis (SCFE). The objective of this study was to compare two cohorts of children (South Africa and the UK) and explore similarities and differences regarding demographic and epidemiological features, incidence and seasonal variation in peak presentation. Patients presenting with SCFE at one of two hospitals were included in the study. A retrospective cohort was collected from hospital records. The following factors were recorded: duration of symptoms, chronicity, stability, seasonality, severity and prophylactic pinning. A total of 137 patients were included in the study - 70 patients (80 hips) from South Africa and 67 patients (73 hips) from the UK. Both sites recorded more than 50% incidence of a chronic slip. There was higher delay to presentation in the UK compared with South Africa (90 vs 60 days, P = 0.0262). The UK population were more skeletally mature (32.8% open triradiate cartilage) compared with the South Africa population (64.9% open triradiate cartilage). In both populations, the most common season of symptom onset was summer. In the UK, the most common season of symptom presentation was in autumn compared with summer in South Africa. This study found significant differences in the two countries, including a more skeletally mature population in the UK. Both cohorts showed seasonal variation in peak incidence, but there was more seasonal variation in peak incidence in the UK - in the summer for onset of symptoms and autumn months for time of presentation.

Seasonal Variation in Slipped Capital Femoral Epiphysis: New Findings Using a National Children's Hospital Database

BACKGROUND

Slipped capital femoral epiphysis (SCFE) demonstrates seasonal variation in certain latitudes but not others. Is such variation influenced by temperature differences, sunlight exposure and subsequent vitamin D production, or other climate variables? It was the purpose of this study to further investigate the seasonal variation in month of presentation for SCFE.

METHODS

Data for this study originated from the Pediatric Hospital Information System for all children with a diagnosis of SCFE from January 1, 2004 through December 31, 2014. From this database the patient's sex, ethnicity, hospital location, and month of presentation was determined. Only those patients treated primarily for SCFE were included. Geographic and climate data [latitude, average annual temperature, precipitation, climate type (Köppen-Geiger and Liss), horticultural plant zone hardiness, and sunlight exposure] for each of the 49 Pediatric Hospital Information System hospitals was determined. Seasonal variation was analyzed using cosinor analysis. A P<0.05 was considered statistically significant.

RESULTS

There were 10,350 cases of SCFE with an overall peak presentation in mid August. For those living at a latitude of >35-degree N there was single peak, a less prominent double peak for those 31- to 35-degree N, and no variation for those <31-degree N. As the average annual temperature increased there was less seasonal variability. Humid, temperate and cold winter climates demonstrated seasonal variation, whereas other climate types did not. Those living in areas having <2500 hours of sunlight per year demonstrated seasonal variation. Further, areas having a photovoltaic solar production potential <5.0 kWh/m/d also demonstrated seasonal variation.

CONCLUSIONS

We discovered new seasonal variation findings regarding SCFE. These are a double peak pattern for those between 31- and 35-degree N latitude; less variability as the average annual temperature increases; and sunlight exposure correlates with seasonal variability. Potential explanations are a rachitic state due to seasonal variation in vitamin D production, and seasonal variation in physeal growth and strength. These new findings will require further investigation.

LEVEL OF EVIDENCE

Level III.