Epiphysiolysis of the femoral head is the most common hip disease in the pediatric population [13, 20], with an incidence of 0.2–0.3 per 100,000 children aged 10–14 years . The aetiology of SCFE is multifactorial and includes endocrine disorders, growth spurs and obesity [2, 4, 7, 21,22,23]. History of trauma to the hip is uncommon . The most common symptoms are pain and limping localized to the hip, groin, thigh or knee [24, 25]. A precise and rapid diagnosis is challenging due to the differential causes of hip pain in young patients . Apophyseal avulsion fracture or apophysitis of the anterosuperior and anteroinferior iliac spine; septic arthritis and adductor muscle strain need to be excluded in these patients [4, 26]. Moreover, also transient synovitis, fractures and Legg-Calvè-Perthes should present similar symptoms. However, these conditions are uncommon in the SCFE age group [4, 26]. A delayed diagnosis could avoid short and long-term complications as avascular necrosis (AVN) of the femoral head and hip osteoarthritis, respectively . Symptom’s duration is used to classify SCFE in acute, acute on chronic and chronic forms. If symptoms present within 3 weeks, it is considered acute; instead, after 3 weeks, it is chronic . The former is the most dangerous because related to a higher rate of AVN. Loder and colleagues  classified the stability of the physis based on the patient’s capacity to bear weight, with or without crutches. Moreover, it is possible to evaluate SCFE by radiographical parameters using the Wilson and Southwick methods [9, 29, 30]. The initial step in the treatment of SCFE is to place the patient on non-weight bearing crutches or in a wheelchair . It is mandatory to prevent slip progression and the insurgence of complications . A closed reduction should not be attempted because it can result in AVN caused by the restricted blood supply to the epiphysis [33, 34]. Some authors recommend the prophylactic treatment of the contralateral hip, but there is no consensus concerning this topic . There is a lack of high-quality literature on SCFE surgical management. However, based on the current literature, the best treatment for stable SCFE is in situ pinning with a single screw, performed regardless of the timing of presentation . The unstable SCFE is related to a higher risk of osteonecrosis (20–50% of cases) [37,38,39], but the proper treatment and the timing associated with the lowest risk of AVN are still debated [11, 36].. The technique described by Parsch and colleagues (open capsulotomy and partial reduction) seems to be the most promising, reporting a low rate of AVN . Moreover, the modified Dunn procedure historically reported satisfactory outcomes with a low rate of necrosis, but it is widely influenced by the surgeon’s technique and skills .
The most relevant complications of SCFE are AVN; degenerative osteoarthritis; acute loss of cartilages known as chondrolysis (reported after SCFE surgery or in untreated SCFE); femoroacetabular impingement [3, 12, 41,42,43]. The rate of AVN varies in the literature, but it is usually more frequent in unstable SCFE compared to stable forms . Loder and colleagues  reported an AVN incidence of 0 and 47% for stable and unstable SCFE forms, respectively. However, recent literature reported an incidence of AVN between 0 and 3.3% for stable forms and 23.9% for unstable forms .
SCFE is a relevant disease in the pediatric population and deserves to be known by clinicians. The main diagnosis code used for this analysis was 732.2 (Epiphysiolysis). The main procedures performed for SCFE were the “Open Reduction Of Separated Epiphysis, Femur” (23.4%), followed by “Limb shortening Procedures, Femur” (8.3%). In Italy, from 2001 to 2015, the mean incidence of hospital admission for SCFE was 2.9 for every 100,000 Italian inhabitants 0–19 years old. The majority of patients were males of the 10–14 years age group, in line with the Swedish results, as reported by Herngren et al. . Males reported a higher mean age compared to females (p < 0.001). The highest number of patients treated was domiciled in the South of Italy (n = 2559), followed by the North (n = 1491) and the Center (n = 823). Otherwise, the highest number of procedures were performed in the North (n = 2422) and the South (n = 1603). The highest number of “extra-regional surgeries” were patients from the South that migrated to the North or the Center. Instead, patients from the North and the Center tended to be hospitalized in their macro-region of domicile. Moreover, patients from the South reported a higher rate of diagnosis of epiphysiolysis compared to the North and the South. A significant decrease in days of hospitalization during the study period was found, but further studies are required to identify possible explanations. The forecast model showed that the demand for SCFE hospital admissions was estimated to remain unchanged from 2015 to 2025.
To our knowledge, the only study on the SCFE surgery trend was performed by Herngren et al. . However, only patients aged from 9 to 15 years were included, while a broader range of age was analysed in the present paper (0–19 years old). Moreover, the study period considered by Herngren et al.  was shorter compared to the present study (from 2007 to 2013 vs 2001 to 2015, respectively).
This study is based on administrative data from different hospitals and macro-regions. The International Classification of Diseases 9 (ICD-9) was used for all the procedures reported. Otherwise, with the ICD-9, it was possible to use different codes for the same surgical procedure. This heterogeneity of codification could lead to an underestimation of our results. Secondly, the database has not been subject to internal validation. Moreover, we found 16.1% of “Removal of Implanted Devices from Bone, Femur” within the procedures included. This data could lead to an overestimation of our results concerning the migratory flux and the total amount of procedures performed. Patients over 19 years old (n = 263) were excluded to avoid underestimation. Moreover, it was impossible to distinguish monoliteral vs bilateral screw fixation because ICD-9 did not fully code it. Lastly, this is a database study, and therefore it is not possible to define specific reasons for migratory flux. Further studies are required to define this trend precisely.