544
Case report
Traumatic posterior hip dislocation and ipsilateral distal femoral fracture in a 22-month-old child: a case report Mert Ciftdemira, Deniz Aydinb, Mert Ozcana and Cem Copuroglua Minor trauma may cause hip dislocation in young children because of physiologic hip joint laxity and the soft cartilaginous structure of the acetabulum. In this work, we report on a 22-month-old boy with right-sided traumatic posterior hip dislocation and ipsilateral distal femoral fracture because of an outdoor motor vehicle accident. The patient was treated with emergency closed reduction and one and a half hip spica under general anaesthesia. The femoral fracture and hip dislocation were healed smoothly without any complication. Traumatic hip dislocation is rare in children, which may occur after trivial trauma. Prognosis is better in younger patients with low-energy trauma and in
Introduction Traumatic hip dislocations are infrequent injuries in children and considered traumatologic emergencies [1]. Traumatic hip dislocations always occur as a result of high-energy trauma in the adult population. Two main mechanisms of injury may result in hip dislocation in the paediatric age group [2]. These injuries can occur with low-energy trauma such as a simple fall in children younger than 5 years of age. In older children approaching skeletal maturity, the mechanism of dislocation approaches the adult pattern, which occurs as a result of high-energy trauma and is often seen in polytraumatized patients. Reduction of the dislocated hip is usually easy and the rate of neurovascular injury and associated traumatic lesions such as fractures of the femoral head and neck, acetabular fractures and soft tissue injuries are much lower in dislocations occurring with low-energy trauma. Nonetheless, dislocations because of high-energy trauma are difficult to reduce and are more prone to related complications. Associated traumatic lesions and neurovascular injury are more frequent in this patient group. Even though the femoral head in children may dislocate in any direction, 90–95% of all traumatic hip dislocations in paediatric patients are posterior dislocations, as it is in adults [3]. Anterior and inferior dislocations are rather rare in children. Posterior traumatic hip dislocation occurs with a posteriorly directed axial load applied to the distal end of the femur when the hip is in the flexion and adduction position. It is typically seen in motor vehicle accidents in which the patient is in the front seat during a head-on collision and the knee strikes the dashboard and pushes the femoral head posteriorly out of the acetabulum [2]. 1060-152X © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
cases treated early. J Pediatr Orthop B 23:544–548 © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins. Journal of Pediatric Orthopaedics B 2014, 23:544–548 Keywords: avascular necrosis of femoral head, dislocations, hip injuries a
Department of Orthopaedics and Traumatology, Trakya University Faculty of Medicine, Edirne, Turkey and bDepartment of Orthopaedics and Traumatology, Near East University Faculty of Medicine, Nicosia, Cyprus Correspondence to Mert Ciftdemir, MD, Department of Orthopaedics and Traumatology, Trakya University Faculty of Medicine, Balkan Yerleskesi, 22030 Edirne, Turkey Tel: + 90 532 7653385; fax: + 90 284 2352338; e-mail: [email protected]
A thorough assessment of history is always important in children with traumatic hip dislocations because the mechanism of injury has prognostic implications. Dislocations with low-energy trauma yield a better prognosis. Worse outcome is predicted in dislocations that occur with high-energy trauma. Traumatic hip dislocation in children should be treated immediately with closed reduction under general anaesthesia after a prompt and definite physical and radiologic examination because of the risk of the avascular necrosis (AVN) of the femoral head. Closed reduction is usually easy to achieve, but interposition of the piriformis tendon, labrum, joint capsule or loose osteochondral fragments may prevent concentric reduction and may require open surgery to achieve concentric reduction [4]. In this paper, we present the course of nonoperative treatment in a 22-month-old male patient with traumatic hip dislocation and an ipsilateral femur fracture that occurred as a result of high-energy trauma. A written consent was obtained from the patient’s parents before writing of this case report.
Case report A 22-month-old boy was referred to our emergency department from a district hospital 2 h after an outdoor motor vehicle accident with a prediagnosis of traumatic hip dislocation. The parents reported that the patient was hit by a truck, but the detailed mechanism of the injury was not clear. Vital signs and examination of the head and neck, thorax, abdomen and spine were normal. At the time of registration, the patient was conscious, crying and alert, with the right lower limb in flexion, adduction and internal rotation posture. The patient was restless and attempted to protect his right lower extremity from DOI: 10.1097/BPB.0000000000000089
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Traumatic hip dislocation Ciftdemir et al. 545
Fig. 1
Fig. 2
Right-sided traumatic dislocation of the hip seen on a plain radiograph taken as a babygram.
examination. In addition, swelling and deformity at the right knee was noted. There were skin abrasions at the popliteal region. Peripheral pulses were bilaterally palpable and capillary refill was equal in both feet. A detailed neurological examination was unavailable, but the patient could extend his ankle and toe. After the initial physical examination, plain radiographic views of suspected regions taken at the district hospital were evaluated and the prediagnosis of right-sided traumatic posterior hip dislocation with fracture of the ipsilateral distal femoral metaphysis was confirmed (Figs 1 and 2). No associated traumatic lesion of the hip joint, such as a fracture of the acetabulum or the femoral head, was observed in the pelvis computed tomography (CT) (Fig. 3). The patient was treated with emergency closed reduction under general anaesthesia within 4 h after the dislocation. Dislocation was easily reduced at the first attempt with longitudinal traction through 90° flexed hip. A concentric reduction was observed at the postreduction plain radiographs. A right one-and-a-half spica cast was applied to the patient after closed reduction of the right distal femoral fracture. Reduction of the hip was concentric and there was no associated periarticular injury in the postreduction CT scan (Fig. 4). Postreduction neurological examination was normal. The early postreduction period was uneventful. The patient was discharged after 2 days of hospitalization. The spica cast was removed during the sixth week. A slight constraint in the
Fracture of the right distal femoral metaphysis seen in plain radiographs.
range of motion of the right hip joint was noted without leg-length discrepancy, pain and instability after cast removal. The patient was allowed to walk full weight bearing after cast removal. Bone scan was normal at the 12th week after trauma. The patient was symptom free at the follow-up examinations, with normal gait and unrestricted range of motion (Fig. 5). There was no evidence of AVN, osteoarthritis and any physeal complication such as coxa magna at the last follow-up of 1 year.
Discussion Traumatic hip dislocation is a very rare injury in the paediatric population that represents 2–5% of all traumatic dislocations in the skeleton. Only 5% of traumatic hip dislocations occur in children younger than 14 years old [5]. The force required to dislocate a hip joint increases with age [3]. Low-energy trauma can cause dislocation in small children whose periarticular
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
546 Journal of Pediatric Orthopaedics B 2014, Vol 23 No 6
Fig. 3
Fig. 5
Posterior dislocation of the femoral head seen in pre-reduction axial CT.
Fig. 4
Plain radiograph of the patient at the post-trauma sixth month. Femoral fracture is united and the right hip joint healed without any complication.
structures are soft, flexible and pliable. Joint laxity, in younger children because of this flexibility, makes the hip more susceptible to dislocation with low-energy trauma [6]. Periarticular flexibility also explains the absence of accompanying bone lesions such as fractures of the acetabulum or the femoral head in contrast to traumatic hip dislocations in adults. Posterior dislocations are far more common than anterior dislocations in children and constitute 90–95% of all cases, as in the adults [3,6]. Even though the periarticular soft tissue structures such as the acetabular labrum and cartilaginous femoral head are more flexible in children, capsule and ligaments are relatively more resistant to stress than are the contiguous bone and cartilage [7]. The contribution of a strong iliofemoral ligament (Bigelow’s ligament) to the stability of the hip joint makes the anterior support stronger than the posterior support in children.
Axial and coronal CT views of both hips immediately after closed reduction in hip spica.
The diagnosis of traumatic hip dislocation is usually not difficult. Posterior dislocations have a characteristic appearance: the affected hip is in flexion, adduction and internal rotation. Anterior and inferior dislocations may be identified by lengthening of the affected extremity;
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Traumatic hip dislocation Ciftdemir et al. 547
these types of dislocations are very rare in children. Avery et al. [8] reported a 9-year-old boy with a traumatic obturator hip dislocation who was treated conservatively. The authors reported that the case was the first paediatric traumatic obturator hip dislocation case in the literature [8]. Radiographs should be checked carefully for any traumatic lesion such as loose osteochondral fragments from the acetabulum or the femoral head that may render concentric reduction impossible. Radiographs should also be checked for fractures of the proximal tibia, patella, distal femur, femoral neck and proximal femoral epiphysiolysis (PFE). PFE or physeal instability should be examined dynamically under a fluoroscopic image intensifier, if suspected. Physeal instability may place the femoral head at risk during reduction manoeuvres in adolescent patients [9]. Physeal separation occurs in ∼ 2% of children with traumatic hip dislocation [5]. Osteonecrosis is a certain outcome in these cases [3]. Neurovascular examination in children with traumatic hip dislocation is mandatory. The peroneal branch of the sciatic nerve is the most likely injured structure in posterior hip dislocations. The incidence of sciatic and peroneal nerve injury has been reported to be up to 20% in children and 13% in adults. Femoral neurovascular structures may be injured in anterior dislocations [5]. A traumatic hip dislocation in a child is a true emergency. Dislocation should be reduced as soon as possible. Reduction under general anaesthesia within 6 h is recommended to minimize the risk of AVN [3]. The risk of AVN is reported to be 3–15% [10–12]. Mehlman et al. [10] reported a 20 times higher risk of AVN in children and adolescents with traumatic hip dislocations, whose hips reduced with a delay of more than 6 h. Traumatic hip dislocations in children younger than 10 years of age are usually easy to reduce. In younger children, the femoral head relocates with an audible snap with gentle traction. Even though closed reduction is usually easy, a congruous reduction is sometimes difficult to achieve because of the interposition of unrecognized osteochondral or labral lesions. Postreduction radiographs should be checked carefully for concentric reduction. Any patient with an asymmetrical joint space widening on plain radiographs taken after closed reduction should be subjected to CT or MRI examination to assess any soft tissue interposition. Failed closed reduction, nonconcentric reduction and dislocations accompanying physeal injury or a displaced femoral head/neck or acetabular fracture are the indications for surgical intervention [6]. The goals for surgery are to clear the obstacles preventing reduction of the femoral head into the acetabulum, identify structures preventing concentric reduction, anatomic fixation of any acetabular or femoral head fractures and soft tissue repair. It is shown that as many as 25% of patients require open reduction [2].
The major long-term complications related to traumatic hip dislocation in children are osteoarthritis, AVN of the femoral head, recurrent dislocation and neurologic injury. Osteoarthritis in the absence of AVN is rare in children; 20% of children with AVN develop osteoarthritis [3]. Recurrent dislocations are more common in children than in adults. It is mostly seen in small children after posterior hip dislocations. Recurrences can be attributed to inadequate healing of the posterior capsule and softness of the cartilaginous posterior acetabular wall. Period of immobilization after reduction of the hip dislocation has no significant effect on the incidence of recurrent dislocations [2,3]. The diagnosis is made on the basis of clinical and arthro-CT or MRI findings. Because of the possibility of chronic instability, Bankart-type repair of the labrum and repair of the joint capsule is indicated in patients with recurrent dislocations [2,13,14]. Hearty et al. [15] reported two cases with traumatic hip dislocation and posterior acetabular wall fractures causing unstable hip joints. Because ossification of the posterior acetabular wall occurs through adolescence, the authors recommend MRI investigation and report that plain radiographs and CT are inadequate for the evaluation of posterior acetabular wall fractures. The incidence of neurologic injury is related to the trauma mechanism; higher energy trauma increases the risk of neurologic compromise. Approximately 5% of children with traumatic hip dislocation will have neurological findings. Return of the sciatic nerve function is expected in most paediatric cases [3]. Herrera-Soto et al. [9] reported five adolescent cases with PFE that occurred during reduction of hip dislocation. Even though it is multifactorial, possible subclinical injury to the physis at the initial trauma and greater force required to reduce the dislocations in adolescent group were the leading reasons for the occurrence of PFE. The authors have reported that all cases in the literature were between 12 and 16 years of age and emphasized the importance of decreased stability of physis during adolescence [9]. Vialle et al. [16] have reported a series of 35 dislocations in skeletally immature patients. The authors observed joint space asymmetry after closed reduction in eight patients. The patients underwent simple arthrotomy after CT examination. Of the eight patients, five were treated by osteochondral fragment resection. The remaining patients required more complex surgeries including acetabular fracture fixation and osteochondral femoral head avulsion repair [16]. Chun et al. [17] reported on a 7-year-old girl with acetabular labrum entrapment after reduction of traumatic hip dislocation. Interposition was detected with MRI during the preoperative period and confirmed surgically. The authors emphasized the importance of MRI for the detection of interposed soft tissue structures, which obscure concentric reduction in children [17]. Hung [18] evaluated the outcomes of treatment in 22 children with traumatic
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
548
Journal of Pediatric Orthopaedics B 2014, Vol 23 No 6
posterior hip dislocation and noted that dislocations in children should be reduced as soon as possible. The interval between injury and reduction could affect prognosis. The author suggests that in delayed treatment, extra interventions, such as open reduction, adductor longus release, psoas tendon lengthening and K-wire fixation of the hip joint, should be carried out to prevent late complications [18]. Sulaiman et al. [19] reviewed 13 patients with traumatic hip dislocations. There were delayed or neglected cases up to 4 weeks in their series. The authors reported excellent results with conservative treatment, except one case, and concluded that closed reduction could be a possible treatment option, even for neglected cases [19]. In our case, successful closed reduction was maintained at the fourth hour after the injury, without any further need for surgery. This case report describes a 22-month-old boy with a traumatic hip dislocation and an ipsilateral femur fracture that occurred as a result of high-energy trauma. In this study, our aim was to emphasize the necessity of urgent treatment and to discuss the risks and complications in this rare traumatic lesion. Traumatic hip dislocation in a child is an uncommon injury and considered a traumatologic emergency. In contrast to adults, lower energy trauma such as a trivial fall may cause hip dislocation in small children. Skeletal maturity and trauma mechanism play an important role in prognosis. Careful clinical and radiologic examination and prompt reduction within 6 h are required to minimize the risk of permanent joint failure. Postreduction radiologic examination is important to assess concentric reduction. Further imaging to assess an unrecognized interposition or an accompanying traumatic lesion is indicated if there is any doubt in terms of concentric reduction. Further intervention aimed at congruency of the hip joint should be performed in case of incongruent reduction. It should be kept in mind that hip dislocation is a rare but major traumatic lesion in children, which may occur after trivial trauma. Prognosis is better in younger patients with low-energy trauma and in cases treated early.
Acknowledgements Conflicts of interest
There are no conflicts of interest.
References 1
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Bressan S, Steiner IP, Shavit I. Emergency department diagnosis and treatment of traumatic hip dislocations in children under the age of 7 years: a 10-year review. Emerg Med J 2014; 31:425–431. Herring JA. Hip dislocations. In: Herring JA, editor. Tachdjian’s pediatric orthopedics. 3rd ed. USA: Saunders Company; 2002. pp. 2273–2283. Herrera-Soto JA, Price CT. Traumatic hip dislocations in children and adolescents: pitfalls and complications. J Am Acad Orthop Surg 2009; 17:15–21. Prince CT, Pyevich MT, Knapp DR, Phillips JH, Hawker J. Traumatic hip dislocation with spontaneous incomplete reduction: a diagnostic trap. J Orthop Trauma 2002; 16:730–735. Hughes MJ, D’Agostino J. Posterior hip dislocation in a five-year-old boy: a case report, review of the literature, and current recommendations. J Emerg Med 1996; 14:585–590. Meena S, Kishanpuria T, Gangari SK, Sharma P. Traumatic posterior hip dislocation in a 16-month-old child: a case report and review of literature. Chin J Traumatol 2012; 15:382–384. Ogden JA. Injury to the immature skeleton. Skeletal injury to the child. 3rd ed. New York: Springer-Verlag Inc.; 2000. pp. 38–68. Avery DM III, Carolan GF. Traumatic obturator hip dislocation in a 9-yearold boy. Am J Orthop (Belle Mead NJ) 2013; 42:E81–E83. Herrera-Soto JA, Price CT, Reuss BL, Riley P, Kasser JR, Beaty JH. Proximal femoral epiphysiolysis during reduction of hip dislocation in adolescents. J Pediatr Orthop 2006; 26:371–374. Mehlman CT, Hubbard GW, Crawford AH, Roy DR, Wall EJ. Traumatic hip dislocation in children: long-term follow up of 42 patients. Clin Orthop Relat Res 2000; 376:68–79. Offierski CM. Traumatic dislocation of the hip in children. J Bone Joint Surg Br 1981; 63-B:194–197. Barquet A. A vascular necrosis following traumatic hip dislocation in childhood: factors of influence. Acta Orthop Scand 1982; 53:809–813. Weber M, Ganz R. Recurrent traumatic dislocation of the hip: report of a case and review of the literature. J Orthop Trauma 1997; 11:382–385. Muratli HH, Dağli C, Biçimoğlu A, Tabak AY. Recurrent traumatic hip dislocation in a child: case report. Acta Orthop Traumatol Turc 2004; 38:149–153. Hearty T, Swaroop VT, Gourineni P, Robinson L. Standard radiographs and computed tomographic scan underestimating pediatric acetabular fractures after traumatic hip dislocation: report of 2 cases. J Orthop Trauma 2011; 25: e68–e73. Vialle R, Odent T, Pannier S, Pauthier F, Laumonier F, Glorion C. Traumatic hip dislocation in childhood. J Pediatr Orthop 2005; 25:138–144. Chun KA, Morcuende J, El-Khoury GY. Entrapment of the acetabular labrum following reduction of traumatic hip dislocation in a child. Skeletal Radiol 2004; 33:728–731. Hung NN. Traumatic hip dislocation in children. J Pediatr Orthop B 2012; 21:542–551. Sulaiman AR, Munajat I, Mohd FE. Outcome of traumatic hip dislocation in children. J Pediatr Orthop B 2013; 22:557–562.
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Case report
Traumatic posterior hip dislocation and ipsilateral distal femoral fracture in a 22-month-old child: a case report Mert Ciftdemira, Deniz Aydinb, Mert Ozcana and Cem Copuroglua Minor trauma may cause hip dislocation in young children because of physiologic hip joint laxity and the soft cartilaginous structure of the acetabulum. In this work, we report on a 22-month-old boy with right-sided traumatic posterior hip dislocation and ipsilateral distal femoral fracture because of an outdoor motor vehicle accident. The patient was treated with emergency closed reduction and one and a half hip spica under general anaesthesia. The femoral fracture and hip dislocation were healed smoothly without any complication. Traumatic hip dislocation is rare in children, which may occur after trivial trauma. Prognosis is better in younger patients with low-energy trauma and in
Introduction Traumatic hip dislocations are infrequent injuries in children and considered traumatologic emergencies [1]. Traumatic hip dislocations always occur as a result of high-energy trauma in the adult population. Two main mechanisms of injury may result in hip dislocation in the paediatric age group [2]. These injuries can occur with low-energy trauma such as a simple fall in children younger than 5 years of age. In older children approaching skeletal maturity, the mechanism of dislocation approaches the adult pattern, which occurs as a result of high-energy trauma and is often seen in polytraumatized patients. Reduction of the dislocated hip is usually easy and the rate of neurovascular injury and associated traumatic lesions such as fractures of the femoral head and neck, acetabular fractures and soft tissue injuries are much lower in dislocations occurring with low-energy trauma. Nonetheless, dislocations because of high-energy trauma are difficult to reduce and are more prone to related complications. Associated traumatic lesions and neurovascular injury are more frequent in this patient group. Even though the femoral head in children may dislocate in any direction, 90–95% of all traumatic hip dislocations in paediatric patients are posterior dislocations, as it is in adults [3]. Anterior and inferior dislocations are rather rare in children. Posterior traumatic hip dislocation occurs with a posteriorly directed axial load applied to the distal end of the femur when the hip is in the flexion and adduction position. It is typically seen in motor vehicle accidents in which the patient is in the front seat during a head-on collision and the knee strikes the dashboard and pushes the femoral head posteriorly out of the acetabulum [2]. 1060-152X © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins
cases treated early. J Pediatr Orthop B 23:544–548 © 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins. Journal of Pediatric Orthopaedics B 2014, 23:544–548 Keywords: avascular necrosis of femoral head, dislocations, hip injuries a
Department of Orthopaedics and Traumatology, Trakya University Faculty of Medicine, Edirne, Turkey and bDepartment of Orthopaedics and Traumatology, Near East University Faculty of Medicine, Nicosia, Cyprus Correspondence to Mert Ciftdemir, MD, Department of Orthopaedics and Traumatology, Trakya University Faculty of Medicine, Balkan Yerleskesi, 22030 Edirne, Turkey Tel: + 90 532 7653385; fax: + 90 284 2352338; e-mail: [email protected]
A thorough assessment of history is always important in children with traumatic hip dislocations because the mechanism of injury has prognostic implications. Dislocations with low-energy trauma yield a better prognosis. Worse outcome is predicted in dislocations that occur with high-energy trauma. Traumatic hip dislocation in children should be treated immediately with closed reduction under general anaesthesia after a prompt and definite physical and radiologic examination because of the risk of the avascular necrosis (AVN) of the femoral head. Closed reduction is usually easy to achieve, but interposition of the piriformis tendon, labrum, joint capsule or loose osteochondral fragments may prevent concentric reduction and may require open surgery to achieve concentric reduction [4]. In this paper, we present the course of nonoperative treatment in a 22-month-old male patient with traumatic hip dislocation and an ipsilateral femur fracture that occurred as a result of high-energy trauma. A written consent was obtained from the patient’s parents before writing of this case report.
Case report A 22-month-old boy was referred to our emergency department from a district hospital 2 h after an outdoor motor vehicle accident with a prediagnosis of traumatic hip dislocation. The parents reported that the patient was hit by a truck, but the detailed mechanism of the injury was not clear. Vital signs and examination of the head and neck, thorax, abdomen and spine were normal. At the time of registration, the patient was conscious, crying and alert, with the right lower limb in flexion, adduction and internal rotation posture. The patient was restless and attempted to protect his right lower extremity from DOI: 10.1097/BPB.0000000000000089
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Traumatic hip dislocation Ciftdemir et al. 545
Fig. 1
Fig. 2
Right-sided traumatic dislocation of the hip seen on a plain radiograph taken as a babygram.
examination. In addition, swelling and deformity at the right knee was noted. There were skin abrasions at the popliteal region. Peripheral pulses were bilaterally palpable and capillary refill was equal in both feet. A detailed neurological examination was unavailable, but the patient could extend his ankle and toe. After the initial physical examination, plain radiographic views of suspected regions taken at the district hospital were evaluated and the prediagnosis of right-sided traumatic posterior hip dislocation with fracture of the ipsilateral distal femoral metaphysis was confirmed (Figs 1 and 2). No associated traumatic lesion of the hip joint, such as a fracture of the acetabulum or the femoral head, was observed in the pelvis computed tomography (CT) (Fig. 3). The patient was treated with emergency closed reduction under general anaesthesia within 4 h after the dislocation. Dislocation was easily reduced at the first attempt with longitudinal traction through 90° flexed hip. A concentric reduction was observed at the postreduction plain radiographs. A right one-and-a-half spica cast was applied to the patient after closed reduction of the right distal femoral fracture. Reduction of the hip was concentric and there was no associated periarticular injury in the postreduction CT scan (Fig. 4). Postreduction neurological examination was normal. The early postreduction period was uneventful. The patient was discharged after 2 days of hospitalization. The spica cast was removed during the sixth week. A slight constraint in the
Fracture of the right distal femoral metaphysis seen in plain radiographs.
range of motion of the right hip joint was noted without leg-length discrepancy, pain and instability after cast removal. The patient was allowed to walk full weight bearing after cast removal. Bone scan was normal at the 12th week after trauma. The patient was symptom free at the follow-up examinations, with normal gait and unrestricted range of motion (Fig. 5). There was no evidence of AVN, osteoarthritis and any physeal complication such as coxa magna at the last follow-up of 1 year.
Discussion Traumatic hip dislocation is a very rare injury in the paediatric population that represents 2–5% of all traumatic dislocations in the skeleton. Only 5% of traumatic hip dislocations occur in children younger than 14 years old [5]. The force required to dislocate a hip joint increases with age [3]. Low-energy trauma can cause dislocation in small children whose periarticular
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
546 Journal of Pediatric Orthopaedics B 2014, Vol 23 No 6
Fig. 3
Fig. 5
Posterior dislocation of the femoral head seen in pre-reduction axial CT.
Fig. 4
Plain radiograph of the patient at the post-trauma sixth month. Femoral fracture is united and the right hip joint healed without any complication.
structures are soft, flexible and pliable. Joint laxity, in younger children because of this flexibility, makes the hip more susceptible to dislocation with low-energy trauma [6]. Periarticular flexibility also explains the absence of accompanying bone lesions such as fractures of the acetabulum or the femoral head in contrast to traumatic hip dislocations in adults. Posterior dislocations are far more common than anterior dislocations in children and constitute 90–95% of all cases, as in the adults [3,6]. Even though the periarticular soft tissue structures such as the acetabular labrum and cartilaginous femoral head are more flexible in children, capsule and ligaments are relatively more resistant to stress than are the contiguous bone and cartilage [7]. The contribution of a strong iliofemoral ligament (Bigelow’s ligament) to the stability of the hip joint makes the anterior support stronger than the posterior support in children.
Axial and coronal CT views of both hips immediately after closed reduction in hip spica.
The diagnosis of traumatic hip dislocation is usually not difficult. Posterior dislocations have a characteristic appearance: the affected hip is in flexion, adduction and internal rotation. Anterior and inferior dislocations may be identified by lengthening of the affected extremity;
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Traumatic hip dislocation Ciftdemir et al. 547
these types of dislocations are very rare in children. Avery et al. [8] reported a 9-year-old boy with a traumatic obturator hip dislocation who was treated conservatively. The authors reported that the case was the first paediatric traumatic obturator hip dislocation case in the literature [8]. Radiographs should be checked carefully for any traumatic lesion such as loose osteochondral fragments from the acetabulum or the femoral head that may render concentric reduction impossible. Radiographs should also be checked for fractures of the proximal tibia, patella, distal femur, femoral neck and proximal femoral epiphysiolysis (PFE). PFE or physeal instability should be examined dynamically under a fluoroscopic image intensifier, if suspected. Physeal instability may place the femoral head at risk during reduction manoeuvres in adolescent patients [9]. Physeal separation occurs in ∼ 2% of children with traumatic hip dislocation [5]. Osteonecrosis is a certain outcome in these cases [3]. Neurovascular examination in children with traumatic hip dislocation is mandatory. The peroneal branch of the sciatic nerve is the most likely injured structure in posterior hip dislocations. The incidence of sciatic and peroneal nerve injury has been reported to be up to 20% in children and 13% in adults. Femoral neurovascular structures may be injured in anterior dislocations [5]. A traumatic hip dislocation in a child is a true emergency. Dislocation should be reduced as soon as possible. Reduction under general anaesthesia within 6 h is recommended to minimize the risk of AVN [3]. The risk of AVN is reported to be 3–15% [10–12]. Mehlman et al. [10] reported a 20 times higher risk of AVN in children and adolescents with traumatic hip dislocations, whose hips reduced with a delay of more than 6 h. Traumatic hip dislocations in children younger than 10 years of age are usually easy to reduce. In younger children, the femoral head relocates with an audible snap with gentle traction. Even though closed reduction is usually easy, a congruous reduction is sometimes difficult to achieve because of the interposition of unrecognized osteochondral or labral lesions. Postreduction radiographs should be checked carefully for concentric reduction. Any patient with an asymmetrical joint space widening on plain radiographs taken after closed reduction should be subjected to CT or MRI examination to assess any soft tissue interposition. Failed closed reduction, nonconcentric reduction and dislocations accompanying physeal injury or a displaced femoral head/neck or acetabular fracture are the indications for surgical intervention [6]. The goals for surgery are to clear the obstacles preventing reduction of the femoral head into the acetabulum, identify structures preventing concentric reduction, anatomic fixation of any acetabular or femoral head fractures and soft tissue repair. It is shown that as many as 25% of patients require open reduction [2].
The major long-term complications related to traumatic hip dislocation in children are osteoarthritis, AVN of the femoral head, recurrent dislocation and neurologic injury. Osteoarthritis in the absence of AVN is rare in children; 20% of children with AVN develop osteoarthritis [3]. Recurrent dislocations are more common in children than in adults. It is mostly seen in small children after posterior hip dislocations. Recurrences can be attributed to inadequate healing of the posterior capsule and softness of the cartilaginous posterior acetabular wall. Period of immobilization after reduction of the hip dislocation has no significant effect on the incidence of recurrent dislocations [2,3]. The diagnosis is made on the basis of clinical and arthro-CT or MRI findings. Because of the possibility of chronic instability, Bankart-type repair of the labrum and repair of the joint capsule is indicated in patients with recurrent dislocations [2,13,14]. Hearty et al. [15] reported two cases with traumatic hip dislocation and posterior acetabular wall fractures causing unstable hip joints. Because ossification of the posterior acetabular wall occurs through adolescence, the authors recommend MRI investigation and report that plain radiographs and CT are inadequate for the evaluation of posterior acetabular wall fractures. The incidence of neurologic injury is related to the trauma mechanism; higher energy trauma increases the risk of neurologic compromise. Approximately 5% of children with traumatic hip dislocation will have neurological findings. Return of the sciatic nerve function is expected in most paediatric cases [3]. Herrera-Soto et al. [9] reported five adolescent cases with PFE that occurred during reduction of hip dislocation. Even though it is multifactorial, possible subclinical injury to the physis at the initial trauma and greater force required to reduce the dislocations in adolescent group were the leading reasons for the occurrence of PFE. The authors have reported that all cases in the literature were between 12 and 16 years of age and emphasized the importance of decreased stability of physis during adolescence [9]. Vialle et al. [16] have reported a series of 35 dislocations in skeletally immature patients. The authors observed joint space asymmetry after closed reduction in eight patients. The patients underwent simple arthrotomy after CT examination. Of the eight patients, five were treated by osteochondral fragment resection. The remaining patients required more complex surgeries including acetabular fracture fixation and osteochondral femoral head avulsion repair [16]. Chun et al. [17] reported on a 7-year-old girl with acetabular labrum entrapment after reduction of traumatic hip dislocation. Interposition was detected with MRI during the preoperative period and confirmed surgically. The authors emphasized the importance of MRI for the detection of interposed soft tissue structures, which obscure concentric reduction in children [17]. Hung [18] evaluated the outcomes of treatment in 22 children with traumatic
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
548
Journal of Pediatric Orthopaedics B 2014, Vol 23 No 6
posterior hip dislocation and noted that dislocations in children should be reduced as soon as possible. The interval between injury and reduction could affect prognosis. The author suggests that in delayed treatment, extra interventions, such as open reduction, adductor longus release, psoas tendon lengthening and K-wire fixation of the hip joint, should be carried out to prevent late complications [18]. Sulaiman et al. [19] reviewed 13 patients with traumatic hip dislocations. There were delayed or neglected cases up to 4 weeks in their series. The authors reported excellent results with conservative treatment, except one case, and concluded that closed reduction could be a possible treatment option, even for neglected cases [19]. In our case, successful closed reduction was maintained at the fourth hour after the injury, without any further need for surgery. This case report describes a 22-month-old boy with a traumatic hip dislocation and an ipsilateral femur fracture that occurred as a result of high-energy trauma. In this study, our aim was to emphasize the necessity of urgent treatment and to discuss the risks and complications in this rare traumatic lesion. Traumatic hip dislocation in a child is an uncommon injury and considered a traumatologic emergency. In contrast to adults, lower energy trauma such as a trivial fall may cause hip dislocation in small children. Skeletal maturity and trauma mechanism play an important role in prognosis. Careful clinical and radiologic examination and prompt reduction within 6 h are required to minimize the risk of permanent joint failure. Postreduction radiologic examination is important to assess concentric reduction. Further imaging to assess an unrecognized interposition or an accompanying traumatic lesion is indicated if there is any doubt in terms of concentric reduction. Further intervention aimed at congruency of the hip joint should be performed in case of incongruent reduction. It should be kept in mind that hip dislocation is a rare but major traumatic lesion in children, which may occur after trivial trauma. Prognosis is better in younger patients with low-energy trauma and in cases treated early.
Acknowledgements Conflicts of interest
There are no conflicts of interest.
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