Traumatic obturator dislocation of the hip associated with ipsilateral subtrochanteric femur fracture in a young adult: a case report

Abstract

Introduction

Traumatic obturator-type anterior dislocation of the hip with an ipsilateral subtrochanteric fracture is rarely encountered in clinical practice. This case presentation described a trauma patient with such a rare scenario.

Case report

This paper reports a case of a 20-year-old Amhara ethnic male patient who had a traumatic anterior dislocation of the hip associated with an ipsilateral subtrochanteric femur fracture after a truck rolled over. There was diffuse swelling of the proximal thigh, and the lower limb was externally rotated. Radiographic examination shows right femur subtrochanteric fracture with ipsilateral obturator-type anterior hip dislocation. Emergency open reduction of the hip dislocation and antegrade intramedullary nailing of the subtrochanteric fracture performed. Subsequent clinical and radiologic follow-up demonstrated good outcomes.

Conclusion

The main peculiarity of the presented case is the association of obturator hip dislocation with ipsilateral femur shaft fracture. Early and stable reduction of the dislocation and firm internal fixation of the fracture as soon as possible will allow early rehabilitation and prevent late complications. At the 4th week of operation, he started non-weight-bearing mobilization.

Introduction

The hip joint is a very stable joint with a high degree of stability and can be dislocated only when high-energy traumas like a car accident occur [1, 2]. Traumatic fracture dislocation of the hip can be contralateral or ipsilateral [2]. Femoral head fracture covers low percentage among all types of hip fracture dislocation, and combination of femoral head and acetabular fracture is even less common [3]. Traumatic anterior dislocation of hip with ipsilateral subtrochanteric fracture is rarely encountered in clinical practice [4]. But posterior dislocation of the hip is repeatedly occurring, and the occurrence chance is nine times higher than anterior hip dislocation due to its mode of dash board injury [5]. Traumatic hip dislocations in children occur most frequently as isolated orthopedic injuries in association with posterior wall acetabular fractures[6].

Traumatic anterior dislocation of hip with ipsilateral subtrochanteric fracture requires emergency evaluation, rapid reduction intervention within 6 hours, and early closed reduction of the joint helps to decrease risk of avascular necrosis and chondrolysis [7,8,9]. Fractures involving the acetabulum and femur head are associated with significant morbidity, disability, and even mortality, especially if they involve vascular structures [10]. In the case of traumatic anterior dislocation of the hip with ipsilateral subtrochanteric fracture, the pull of abductors and external rotators acting on the short proximal fragment forced the femoral head to slide through the tear in the anterior capsule. The dislocated femoral head occluded the femoral artery [11]. It can be assumed that the lower leg can be dislocated through abduction during flexion or abducent, external flexion during traumatic anterior dislocation of the hip with an ipsilateral femur fracture [12].

The case of traumatic obturtator type anterior dislocation of the hip with ipsilateral subtrochanteric fracture is rare, and there is limited literature about it, which makes it a very challenging case [9, 11,12,13]. Here we report a case of right side traumatic obturator hip dislocation with ipsilateral subtrochanteric femur fracture in a 20-year-old male patient.

Case presentation

A 20-year-old male, of low socioeconomic status, Amhara ethnicity, and an assistant driver by occupation presented with a road traffic accident of 1 day duration. He was an assistant driver of a truck, and the truck rolled over while running with high speed, and he sustained trauma to his right thigh and hip area. At presentation, he was conscious but unable to mobilize his right lower limb. The patient complained of severe pain over the right buttock and thigh area. He had manifestations of pain, bruising, swelling, deformity, shortening, and instability around the thigh and injured leg, as it turned out. The patient confirmed that the hip and femur bone or joint had never been damaged before. He has no medical or surgical history. On arrival in the emergency room, analgesics were given and he was clinically examined. Vital signs were in the normal range. A complete examination of the involved and uninvolved extremities including complete strength testing and neurovascular examination was performed. On physical examination, the proximal right thigh was swollen, and the right hip was in an abduction and external rotation position with the femur head palpable in the obturator area. Femoral and popliteal pulsation was palpable. Femoral nerve and obturator nerve assessment was intact. Patient’s level of consciousness was determined to be 14 using glasgow coma scale the (GCS). The patient was recommended to get a computed tomography (CT) or magnetic resonance imaging (MRI), but the service was not available in this hospital at the moment, and the patient could not get the service. A pelvic and thigh radiograph was taken and showed right side obturator-type anterior hip dislocation with an ipsilateral subtrochanteric femur fracture (Fig. 1). In addition to these routine blood investigations of complete blood count (CBC), cross match, and rapid blood sugar were sent and were found to be within normal ranges.

Fig. 1

Anterior–posterior (AP) x-ray showing subtrochanteric femur fracture with ipsilateral obturator-type anterior hip dislocation

Therapeutic intervention

Then the patient was taken to the operation theater, and spinal anesthesia was given. Using an incision over the greater trochanter, a 5 mm Schanz pin was inserted over the greater trochanter (Fig. 2) to be used as a joystick, and closed reduction was tried with sustained traction in the abduction position and pressure over the femur head was applied from the obturator area to push into the acetabulum, but it was not successful. Then, using anterolateral approach to the hip, the capsule was opened and the femur head was reduced to the acetabulum. Then the subtrochanteric fracture was opened by extending the anterolateral approach of the hip distally. The fracture was reduced and fixed with an antegrade interlocking intermuscular (IM) nail using piriformis entry to the femoral canal to avoid the risk of varus malreduction (Fig. 3). At the end of the operation, the stability of the hip was checked by performing a 90° flexion, internal–external rotation, and abduction–adduction, and it was stable.

Fig. 2

Intraoperative picture showing a 5 mm Schanz pin inserted over the greater trochanter and laterally directed traction applied to reduce the femur head

Fig. 3

Postoperative x-ray showing the right femur head reduced and the subtrochanteric femur fracture fixed with interlocking IM nailing

Follow-up and outcome

Postoperatively, the left lower limb was immobilized by a posterior splint with the knee in extension position for two weeks. Subsequently, knee-bending exercises and quadriceps strengthening started. Then he started partial weight-bearing mobilization with a walker after 4 weeks. Radiologic assessment using x-rays was done regularly, starting from 6 weeks postoperatively until 1 year. Subsequently, the patient resumed his daily activities without any hip pain, and he has no functional limitation.

Discussion

The hip is a stable joint with good congruence between the femoral head and acetabulum and reinforced by thicker capsules and strong ligaments [9], and so it requires significant trauma for hip dislocation. The most common trauma is posterior dislocation, while anterior hip dislocation accounts for 10–15% of cases, while obturator hip dislocations occur in less than 5% of all traumatic hip dislocations [12]. Anterior hip dislocations result from high-energy trauma, which causes forced abduction and external rotation of the hip [11]. Based on the position of the hip at the time of impact, it can be a superior type if the hip is in the extension position or an inferior type if the hip is in the flexed position [14]. Joint reduction with fracture fixation allowed early rehabilitation, and a delay of more than 6 hours resulted in a fourfold increased risk of avascular necrosis development [7, 9, 13]. Traumatic anterior dislocation of the hip with an ipsilateral subtrochanteric fracture requires a special mention because of the peculiar mechanism of injury. There are often problems encountered in treating such cases. Hip dislocation is an orthopedic emergency requiring urgent reduction to prevent late complications such as avascular necrosis (AVN) of the femur head, osteoarthritis, neurovascular injury, and heterotopic ossification [9].

For this particular case of traumatic anterior dislocation of the hip with an ipsilateral subtrochanteric fracture, closed reduction was tried with sustained traction in the abduction direction and pressure over the femur head applied from the obturator area to push into the acetabulum, but it was not successful. According to experience of another case report, mandatory open reduction is indicated in cases of failed closed reduction, particularly in irreducible dislocations and closed reduction of hip dislocations associated with ipsilateral extremity fracture [15].

Then, using anterolateral approach to the hip, the capsule opened and the femur head was reduced to the acetabulum. Some previous case presentations followed a similar treatment approach [6], and others applied a closed reduction of the dislocated hip [11, 12]. One case report does not recommend open reduction for acetabulum dislocation at all [13]. The subtrochanteric fracture was opened using lateral approach to the femur, and the fracture reduced and fixed with an antegrade interlocking IM nail [7].

Conclusion

The outcome of such cases depends on rapid evaluation and early intervention, and it usually requires a multidisciplinary approach to identify and treat associated life threatening conditions. Early and stable reduction of the dislocation and firm internal fixation of the fracture as soon as possible will allow early rehabilitation and prevent late complications. The main peculiarity of the presented case is the association of the anterior–inferior dislocation with ipsilateral femur shaft fracture. The latter can be explained by the developing of powerful forces that act on the shaft. Another rare aspect of this case is the absence of associated acetabular fracture even though he had contra-lateral iliac wing fracture. Hip dislocation is an orthopedic emergency requiring urgent reduction to prevent late complications such as AVN of femur head. Other complications include osteoarthritis, neurovascular injury, and heterotopic ossification.