Femoral neck fractures, which usually develop during a fall, are among the most common fractures in the older population; in contrast, these are rare in children [1, 2]. They typically result from high-energy trauma, including falls from heights, motor vehicle accidents, and bicycle accidents. Pathological fractures should be suspected in the setting of low-energy injuries or minor trauma. Although a number of case reports have described bilateral femoral neck fractures in the pediatric population, they are associated with polytrauma, osteopetrosis, vitamin D deficiency, or slipped capital femoral epiphysis [3, 4, 5]. To our knowledge, no case of pediatric bilateral femoral neck fractures that developed during an epileptic seizure has been reported. This report presents the rare case of a pediatric patient with bilateral femoral neck fractures from epileptic seizures.

A 13-year-old boy had an epileptic attack that was self-terminated. One hour after he went to sleep, he had another seizure and could not walk; therefore, he was immediately admitted to the hospital. The parents confirmed that the patient did not fall from the bed. He had a history of epilepsy and mild developmental retardation and was prescribed with sodium valproate at 8 months of age. It was discontinued 2 months before the episode because his condition was well controlled.

Examination

In the emergency department, the patient’s vital signs and general examination results were normal; however, the patient complained of bilateral thigh pain. His serum creatine kinase (CK) level was elevated to 5032 U/L (reference range: 51–270 U/L). Although whole-body computed tomography (CT) was performed, the attending emergency physician and pediatrician did not identify bilateral femoral neck fractures from the scan. He was admitted to the emergency department because myositis and rhabdomyolysis were suspected. Sodium valproate was resumed, and prednisolone infusion (once per day) was administered. Though the CK level decreased daily, the patient had persistent bilateral thigh pain. Hence, he was referred to the orthopedic department 3 days after admission.

Radiography

Bilateral femoral neck fractures were revealed by frontal hip radiography. The fractures were classified as Delbet-Colonna type II (Fig. 1a). CT showed severe retroversion at both fracture sites (Fig. 1b). Surgical reduction and fixation were planned because the displacement of both fractures was apparent.

Operation

Closed reduction was achieved on both sides with traction and external rotation. Fixation with two cannulated screws on each side and capsular decompression was performed (Fig. 2).

Postoperative course

The patient was placed on bed rest for 3 weeks postoperatively, after which active movement of the hip joints was initiated, and he was allowed to sit. Training on all fours began at week 6. Ultrasound fracture therapy was also administered. Femoral head necrosis was not observed on a 9-week postoperative magnetic resonance imaging scan (Fig. 3a). Complete bone union was confirmed at the 10-week postoperative CT (Fig. 3b), and weight-bearing began. We allowed the patient to walk with full weight-bearing 12-week postsurgery. The screws were removed 6 months after the initial surgery. At the 1-year postoperative follow-up, the patient had no symptoms in the bilateral hip joints, with an almost normal range of motion. Plain radiographs did not show avascular necrosis (AVN) or early osteoarthritis (Fig. 4).

Pediatric femoral neck fractures comprise <1% of all fractures in children [1, 2]. They represent an orthopedic emergency. Nonoperative treatment is rarely indicated because of the high risk of complications. Closed or open reduction and internal fixation are the gold standard in treatment. Fracture nonunion and AVN are common and devastating complications of femoral neck fractures. The risk of AVN depends on the Delbeta type; there is a 100% risk of AVN with type I fractures, 52% with type II, 27% with type III, and 14% with type IV ^[6]. Meanwhile, the rate of nonunion can be as high as 21%. In the current case, urgent surgery after diagnosis (anatomical reduction, hip joint decompression, and rigid internal fixation), supplemented by ultrasound fracture therapy, contributed to bone union without AVN on the both sides. Compared with the general population, epileptic patients are known to have a greater risk of developing fractures ^[7]. Approximately 30–35% of patients with epilepsy experience some seizure-related injuries. Fractures occur in 0.25–2.4% of patients with seizures [8, 9]. A recent systematic review reported that the most common fractures caused by epilepsy were the following: bilateral posterior shoulder joint dislocation fractures (33%), thoracolumbar spine compression fractures (29%), skull and jaw fractures (8%), and bilateral femoral neck fractures (6%) ^[9]. Uncontrolled violent muscle movements that are seen in epileptic seizures cause atypical bone fractures; however, these injuries are often missed, and diagnosis is delayed because of a lack of appropriate knowledge, clinical suspicion, and examination ^[8]. Early diagnosis is required to avoid subsequent complications, such as AVN; therefore, not only orthopedic surgeons but also pediatricians, neurologists, and emergency physicians should be aware of postepileptic fractures. Furthermore, antiseizure medication (ASM) has been reported to lead to bone fragility, although the mechanism has not been well clarified ^[10]. In a systematic review, Griepp et al. revealed that there are no clear trends in the serum levels of biochemical markers such as vitamin D, parathyroid hormone, calcium, and phosphate by ASM, but many studies have shown a strong correlation between decreased bone mineral density (BMD) and ASM use ^[11]. Berkvens et al. showed that among epileptic patients aged between 18 and 88 years, 92 of 205 (44.9%) had osteopenia, while 65 (31.7%) had osteoporosis ^[12]. In the same study, 156 fractures were described in 82 (40.0%) patients during their follow-up ^[12]. Berkvens et al. also reported that 16 of the 24 (66.6%) children and adolescents (aged 5–17 years) had a low BMD; three of them were diagnosed with osteoporosis, and 10 (41.7%) had at least one fracture in their life ^[13]. In a study by Ecevit et al., sodium valproate therapy for epilepsy considerably reduced BMD in the femoral neck area in children ^[14]. In a recent study, the risk of fractures in children with ASM therapy was significantly elevated compared to the control group without ASM therapy 4 years after initiating the drug ^[15]. Although there is a paucity of research on why or how ASM causes weakness of the bones without an abnormal range of serum concentration, osteoporosis treatment, such as bisphosphonate therapy, may be useful for patients taking ASM.

Pediatric femoral neck fractures without high-energy injuries are uncommon; however, they are known to be a complication of postepileptic seizures in adults and children. Furthermore, it is known that the long-term use of ASM causes a decrease in BMD. Our report describes a pediatric patient with simultaneous bilateral femoral neck fractures without any trauma that was successfully managed by surgical fixation, a careful postoperative course, and ultrasound fracture therapy. We present this case to raise awareness of fractures in children with postepileptic seizures.

This rare case of a pediatric patient with bilateral femoral neck fractures due to epileptic seizures highlights the possibility of fractures in children with postepileptic seizures. These may be managed by surgical modalities and ultrasound fracture therapy.