1 Introduction

Floating hip injuries are defined as the fracture of the acetabulum or pelvis and ipsilateral femur fracture. These fractures can also be associated with anterior and posterior dislocation of the ipsilateral hip.¹ These injuries are caused by high energy trauma like road trauma accident or fall from a height. They are rare in occurrence with an incidence of 1:10,000 fracture. Surgical management of poly traumatized patients with isolated femur, acetabular and pelvic fractures has been well discussed in the literature; however, literature provides scant information on surgical management of these fractures in the pediatric population.

Muller classified floating hip injuries into three types, in which type A includes an acetabular fracture, type B includes a pelvic ring fracture, and type C includes both acetabular and pelvic ring fracture.² Simultaneous occurrences of unilateral pelvic injury, central hip fracture-dislocation, and femur diaphyseal fracture are not reported in the literature. In our report, we present a variant of floating hip injury in a 10-year-old child and its management. The guardian of the patient was informed that the data concerning their case would be submitted for publication, and they provided consent.

2 Case report

A 10-year-old male child was brought to our emergency department with a history of direct fall on the left hip from a school bus 3 hours back. The child had swelling and pain localized to the left groin region and left hip movements were restricted. In emergency room, child was evaluated using the Paediatric Advanced Life Support (PALS). Glassgow come score (GCS) on arrival was 15/15. There were no signs of an open injury, any other systemic injury, or musculoskeletal injury. The dorsalis pedis pulse was palpable and sciatic nerve examination was normal. The child was hemodynamically stable with a heart rate of 96/min and systolic blood pressure of 110 ​mmHg. Radiographs of the pelvis and both hips revealed left hip central fracture-dislocation involving the anterior as well as a posterior column of the acetabulum with ipsilateral femur fracture in the proximal diaphyseal region (Fig. 1). Radiographs of the chest and cervical spine were normal. Child was rescucited with intravenous fluids. Given the complex fracture pattern of the pelvis, a CT scan was performed for classifying the pelvic and acetabular fracture patterns. CT scan revealed the following details – triradiate cartilage injury, both column fracture with iliac blade fracture, and sacroiliac joint disruption with rami fractures (Fig. 2 a,b). The injury was classified as a variant of type C floating hip injury. Since the child was hemodynamically stable, definitive fixation of both fractures was planned in a single stage. The surgical planning consisted of intervention by a team of experts consisting of pediatric orthopedic surgeon and a adult pelviacetabular surgeon. A thomas splint was applied and the child was posted as a routine trauma case the next day morning. Child was given general anaesthesia and femoral fracture fixation was performed by the pediatric orthopedic surgeon in a supine position with closed retrograde elastic stable intramedullary nailing (ESIN) using standard surgical technique. After wound closure, the child was assessed by the anaesthetist for hemodynamic stability. The hemodynamic status was found to be stable and subsequently lateral position was given. After preparation and drapping of the limb, open reduction and plate osteosynthesis of the posterior column and iliac blade was performed by pelviacetabular surgeon using Kocher-Langenbeck approach. The pelvic injury was conserved. Radiographs done in the immediate postoperative period showed a well reduced femur fracture with ESIN in-situ and well reconstructed acetabulum and recon plate in-situ (Fig. 3a,b,c).

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Fig. 1 Anteroposterior and Judet views of the pelvis revealed left hip central fracture-dislocation with ipsilateral femur fracture in the proximal diaphyseal region.

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Fig. 2 [A] – Axial CT view of the hip showed left sided triradiate cartilage injury with comminuted acetabulum fracture Fig. 2 [B] – Axial CT view at SI joint level showed left SI joint dislocation and iliac blade fracture.

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Fig. 3 [A], [B] and [C] – Radiographs in the immediate post-operative period showing acceptable alignment and fixation.

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In the post-operative period, immobilization was given in a long leg knee brace. The child was kept in bed for initial 3 weeks and passive isometric hip exercises were initiated. Wound healed well and suture removal was done at 2 weeks. At 3 weeks, non-weight bearing walking with walker and active hip and knee range of motion exercises were initiated with the help of physical therapist. The patient achieved full weight at 3 months after radiological evidence of adequate fracture healing. At 6 months, all fractures healed well and the patient achieved a full hip range of motion. There was no functional limitations (Fig. 4). The child had an excellent functional outcome with a Harris hip score of 100. At 14 months follow-up radiograph, all fractures remodeled well with premature closure of triradiate cartilage (Fig. 5). Clinically, there was ipsilateral limb lengthening of 1 cm which can be attributed to post-traumatic hypervascularity as reported by some authors.^3,4 Femoral nails were removed and limb lengthening was treated conservatively with adequate shoe raise on the opposite limb. The child is being followed up at yearly intervals.

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Fig. 4 At 6 months, patient achieved full range of motion with ability to do active straight leg raise and sitting crossed legged.

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Fig. 5 At 14 months follow-up, all fractures healed well.

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3 Discussion

Floating hip injuries and the fracture patterns were first reported by Liebergall et al. in a series of 17 patients.⁵ He reported two types of injury patterns: a posterior acetabular fracture with concomitant ipsilateral femoral fracture pattern and a central acetabular fracture with an ipsilateral femoral fracture.¹ Muller et al. in a review of 40 patients, described three types of injury pattern - type A (acetabular and femoral fractures), type B (pelvic ring and femoral fractures), and type C (all three fractures present) patterns.²

Our case does not fit into any previously described injury pattern in the literature. We prefer to describe it as a variant of floating hip injury. To our knowledge, this is the first case report describing the concomitant occurrence of ipsilateral femoral shaft fracture, acetabular fracture-dislocation, and pelvic injury in a pediatric population. The management of such complex injury is further complicated due to the rarity of the injury and lack of standardized treatment strategies for fixation in both adults as well as children.

The primary controversy in surgical management was the priority of fixation of the fractures. Internal fixation of femoral fractures requires preoperative and intraoperative traction, but this is difficult in a scenario when there is an associated hip fracture-dislocation. Alternatively, acetabular fractures require a stable femur to get adequate reduction and maintain an unstable hip in located position.⁶ Liebergall et al. advocate fixing the femoral fracture first, for intra-articular acetabular fracture reduction through traction.¹ Tiedeken et al. recommend an early open emergency reduction in hip dislocation cases, due to the risk of possible necrosis of the head in an avascular state.⁷ Wu et al. reported better bedside care with the emergent insertion of an external fixator for pelvic fracture and traction for the femur.⁸ Kregor et al. described multiple modalities of fixation from the primary fixation of acetabulum followed by antegrade nailing for the femur, acetabular fixation followed by femoral plating, and retrograde femur nailing followed by acetabulum fixation.⁹ Some authors also recommend a minimally invasive approach, by doing both acetabular and femur fixations through the same approach.¹ The majority of the literature focuses on femoral fixation preceding definitive management of acetabular and pelvic injuries.^10,11 All these studies have been reported in adults and they do not take into account, a concomitant hip fracture-dislocation.

Suzuki et al. reported heterotopic ossification after fixation of acetabulum and femur through the same approach in adults.¹⁰ Initial anterograde nailing for femur carries a risk of the relative instability of proximal femur, a concern of avascular necrosis, and further soft tissue damage for treatment of acetabular fracture.⁹ Early fixation of the femoral fracture avoids the risk of pulmonary complications due to fat embolism syndrome.¹

Through the available literature and due to the complexity of the injury around the hip, we decided to take a multidisciplinary approach. Since the child was hemodynamically stable, the decision was taken to perform a single staged fixation of both femur and acetabulum. Initial femoral fixation by retrograde ESIN was performed in a supine position by a pediatric orthopedic surgeon. Hemodynamic parameters were re-evaluated by the anaesthetist after femoral fixation and open reduction and plate osteosynthesis were performed by a pelvic-acetabular surgeon using KL approach. The KL approach provides a complete visualization of the posterior acetabular fracture and reduction of the femoral head.¹⁰ The complexity of this injury pattern, emphasizes the need for managing each case on an individual basis. A successful outcome in such a case involves following simplified management plans and thus allowing for sequential surgical treatment of the polytraumatized patient. Studies with a larger sample size are required to validate our results and to make definite treatment strategies for these injuries in children.

4 Conclusion

Surgical management of floating hip injuries in the pediatric population is challenging. From our report, we intend to highlight the importance of a multidisciplinary approach in these fractures. We also report surgical management of floating hip variant and excellent functional outcome at short-term follow-up of 14 months.

Financial support and sponsorship

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Informed consent

Detailed written informed consent obtained for publication of data, images, and treatment-related documents without any objection.

Authors contribution

SP and AP were the chief orthopaedics surgeons, evaluated the patient, reviewed the article. VS and UV obtained the radiographs of the patient, obtained informed consent from the patient for the publication and were responsible for the writing of the draft of the manuscript.

Institutional ethical committee approval

Not taken.