Management and Outcomes of Anterior Hip Dislocation with Multiple Comminuted Fractures from a Vehicular Crush Injury in a 44-Year-Old Woman

Introduction

The hip joint is composed of the femoral head and acetabulum and is surrounded by the most powerful joint capsule and ligaments. However, the lower wall of the joint capsule is relatively weak, and the femoral head can easily protrude from below when the hip joint is dislocated. The type of dislocation is determined by the position of the femoral head and the direction of the force. Since the classification of hip dislocation is based on the position of the femoral head after dislocation, we believe that this injury can be more clearly described as femoral head dislocation. The following referenced articles use femoral head dislocation instead of hip dislocation to describe this injury. This report describes the presentation, diagnosis, and treatment of a 44-year-old woman with anterior hip dislocation and multiple comminuted fractures due to a vehicular crush injury.

Case Report

On April 14, 2018, a 44-year-old woman was run over twice by the rear wheel of a reversing truck while walking. She felt severe pain in the right hip, persistent dull pain in the chest, abdomen, and right knee, accompanied by external rotation and abduction deformity of the right lower limb, movement disorder, and the inability to stand and walk. Four hours later, she was admitted to a local hospital. She was conscious and hemodynamically unstable, and the catheter showed hematuria. Radiographic examination revealed multiple pelvic fractures with femoral head anterior dislocation (Figure 1A, 1B) and injuries. Ten hours after admission, pelvic external fixation and right femoral supracondylar bone traction were performed. After surgery, she was treated with 2.0 g intravenous drops of sulbenicillin sodium every 6 h to prevent infection, ambroxol to eliminate phlegm, mouse nerve growth factor to nourish the nerves, and oral Chinese medicine to keep oral cleanliness. Due to gastrointestinal dysfunction, the patient took only a small amount of liquid. Lansoprazole injection was used to protect the stomach and inhibit acid, and compound amino acid injection, compound sodium chloride injection, and vitamin injection for were given for nutritional support therapy.

Five days after the injury, the patient was transferred to our hospital. Referral diagnoses included the following: multiple pelvic comminuted fractures (OTA type C-3.3), Denis type III sacral fractures (Figure 1C), bilateral superior and inferior pubic ramus fractures (Figure 1B), abdominopelvic hematocele with mesenteric contusion, bladder wall contusion, L1-5 bilateral transverse process fractures with L4 spinous process fracture (Figure 1D), left lateral malleolus avulsion fracture (Figure 1E), right femoral lateral condyle fracture (Figure 1F), right 12th costeovertebral joint dislocation, right 2nd and 7th to 9th rib fractures, traumatic wet lung of both lungs with bilateral pleural effusion, right knee dislocation (Figure 1G), multiple skin and soft tissue contusions throughout the body, and mild fatty liver. The injury severity score was 29. Fortunately, she had no symptoms of lumbosacral nerve injury. The laboratory results were as follows: white blood cell count: 11.9×109/L, hemoglobin: 101 g/L, red blood cell count: 3.5×1012/L, indirect bilirubin: 16.2 μmol/L, total protein: 59.2 g/L, albumin: 35.2 g/L, alanine aminotransferase: 57 U/L, aspartate aminotransferase: 48 U/L, chloride: 98.3 mmol/L, calcium: 2.0 mmol/L, creatine kinase: 1345 U/L, creatine kinase isoenzyme: 46.5 U/L, and lactate dehydrogenase: 483 U/L. The infection markers were as follows: amyloid A: 177.1 mg/L, hypersensitive C-reactive protein: 29.4 mg/L, calcitonin original: 0.32 ng/mL, interleukin: 8.2 pg/mL, and D-dimer: 14003 ng/L.

The patient underwent a computed tomography (CT) scan (Figure 2) and pelvic 3-dimensional (3D) reconstruction again (Figure 1H, 1I), displaying right multiple fractures with femoral head dislocation and slightly widened right pelvic sacroiliac joint gap: a sacroiliac hematoma. Clinical evaluations were as follows. The pelvis was fixed with external fixator, the right femoral supracondylar traction pin was in place, the right lower limb was in abduction, and the right ankle was swollen and deformed. The muscle tone of both upper limbs was normal, the lower limbs were immobilized, the pulse of the bilateral dorsal foot was present, and the movement of the toes was good. Multiple skin contusions were present all over the body.

Five days after admission, open reduction internal fixation was performed. Rectus femoris, iliopsoas tendon, or hip capsule soft tissue intercalation [1] results in closed reduction failure and requires open reduction [2,3]. The Smith-Petersen or Watson-Jones approaches can be used [4–7]. In this case, a longitudinal incision approximately 6.0 cm in length was made from the surface projection of the anterior inferior iliac spine, which was made along the intermuscular space of the sartorius, rectus femoris, and iliopsoas muscles (Figure 3A). An intraoperative photo shows the cartilaginous contusion of the femoral head (Figure 3B). The femoral nerve, lateral femoral cutaneous nerve, femoral artery and vein, and lateral circumflex femoral artery were protected. The femoral head could not be reduced due to the incarceration of the joint capsule. The intra-articular hematoma and free cartilaginous debris were removed. Two 4.0-mm Kirschner wires were inserted into the greater trochanter of the femur. The surgeon grasped the Kirschner wires, pulled the femoral head outward and forward, assisted the knee flexion traction, pulled the femoral head out of the obturator foramina, and returned the femoral head to the acetabular fossa for reduction. With the help of Kirschner wires, the femoral head was reduced by traction during hip flexion and knee flexion [4–8]. After the dislocation of the femoral head was restored, the comminuted obturator formamen fracture was reduced and fixed with a reconstructive plate and cortical screws. Then, on the orthopedic table in a lateral position with extension of the incision to posterior of the femur and acetabulum, the sacrum fracture was reduced and fixed with plates and screws, using C-arm imaging. Continuous passive motion was performed on the third day after surgery. An intraoperative autologous blood transfusion of 290 mL and a transfusion of 2 U of suspended erythrocytes were performed, with no adverse reactions. After the operation, the patient was transferred to the Intensive Care Unit and was given preventative measures for infection and symptomatic supportive treatments.

Twenty days after admission, anterior pelvic ring internal fixation was performed. The patient was hospitalized for 33 days. Postoperative pelvic X-ray after 2 days revealed the restoration of integrity and continuity of the pelvic ring (Figure 4A–4C). Crutches assisted in partial weight-bearing ambulation for 1 month postoperatively. At 3 months after surgery, CT showed osteotylus growth and near-normal walking. The internal fixator was removed at 1 year after surgery. Five years after the surgery, pelvic CT revealed removal of the internal fixator, fracture healing, and osteophyte formation below the right acetabulum (Figure 4D–4F). Three years after the surgery, the patient recovered well in single-leg weight-bearing and flexion squatting functions (Figure 5).

Discussion

According to the position of the femoral head relative to the acetabulum, femoral head dislocation can be classified as anterior, posterior, or central dislocation. However, a “central dislocation” is in fact a medial displacement of the femoral head secondary to a displaced acetabular fracture. This poorly descriptive term, central dislocation, is an outdated phrase and is no longer relevant to the classification of hip injuries [7]. Anterior dislocation accounts for only 7% to 13% of all femoral head dislocations [9]. Femoral head anterior dislocation accounts for less than 5% of pediatric traumas [10–13]. The Epstein classification, which divides anterior dislocation of the femoral head into anterior inferior type and anterior superior type, is currently the most widely used method [14,15]. Ninety percent of cases involve the anterior inferior type, with the femoral head located in the obturator foramen. The characteristic imaging findings are that the femoral head covers the obturator ring, and the femur is in abduction and external rotation, with femoral head palpable near the obturator foramen. The present patient’s obturator-type dislocation is consistent with this characteristic imaging finding (Figure 2A, 2B). Anterior superior dislocation is rare and can be divided into pubic or iliac dislocation [16]. A palpable femoral head in the groin is helpful for differentiating it from femoral neck fracture. On anteroposterior pelvic radiograph, it can be easily confused with femoral head posterior dislocation [16]. On anteroposterior radiograph, anterior superior dislocation revealed protrusion of the lesser trochanter. In posterior dislocation, the lesser trochanter is not prominent or superimposed on the femoral shaft [17], and the femur adducts and rotates internally.

Due to the extreme abduction and external rotation of the hip joint, the top of the greater trochanter has a leverage effect on the acetabular margin, resulting in the femoral head breaking through the joint capsule from the weak area between the iliofenral ligament and the pubofemoral ligament and prolapse. The position of the hip, the force vector applied, and the individual’s anatomy all affect the direction of the dislocation and whether a fracture dislocation or pure dislocation occurs. The less common anterior dislocations are the result of hyper-abduction and extension [6]. In our patient, the abducted hip was crushed by a wheel, to exert an external rotational force through the femur, leading to anterior dislocation. Violence continued to be applied to the femoral head, causing obturator fracture. Due to the tight fixation of joint ligaments, further abduction of the femoral head can cause femoral neck fracture [18–20]. This type of injury, Young-Burgess lateral compression type III [21], also known as windswept pelvis [22], is a typical wheel crushing injury.

Femoral head dislocation caused by a traffic accident requires significant violent external energy. The associated injuries in the head and neck, thorax and abdomen, spine, and limbs should be examined to prevent a missed diagnosis and misdiagnosis. Traumatic hip injuries have high morbidity and mortality rates due to multiple organ damage, primarily of the extremities, chest, and abdomen. There is a 95% incidence of injury to other areas of the body in patients with hip dislocations [23]. Therefore, after performing the history and physical, a provider must complete a neurovascular examination prior to attempting closed reduction. Neurovascular complications associated with anterior dislocations are also rare but include injury to the femoral nerve, artery, and vein [24]. Direct neurologic injury in patients with isolated anterior dislocation of the femoral head has yet to be reported [25]. In the present case, the patient’s blood was in a hypercoagulable state after the fracture and was prone to thrombosis, with the risk of embolism in important organs, such as the heart, brain, and lungs, even being life-threatening. Two recent cases demonstrate the possibility of thrombosis occurring from an anterior hip dislocation [26,27]. Tabuenca and Truan reported that 46 of 187 patients (25%) with fracture or fracture-dislocation of the hip had an ipsilateral knee injury [28] (Figure 1G). This is consistent with our case, in which the patient had injuries to the anterior and posterior cruciate ligaments and medial and lateral collateral ligaments of the right knee, with partial tears. The sequelae after traumatic hip dislocation comprise a long list: irreducible dislocation, recurrent dislocation, avascular necrosis of the femoral head, early degenerative osteoarthritis, nerve injury, and heterotopic ossification [29,30]. Significant associated injuries can have a negative impact on results [6]. Pape et al [31] found high rates of complications in patients with an injury severity score of greater than 18, including 5 of 17 patients with early arthritis, and 7 of 17 patients with avascular necrosis. In addition, 64% developed heterotopic ossification, which did not appear to correlate with open procedures.

Previous reports have indicated that associated injuries do not directly affect outcomes. However, Jacob et al stated that regardless of treatment mode, severe fracture dislocations caused unsatisfactory results. In this series, multiple injuries accompanying dislocation affected optimal prognosis [29]. Likewise, associated fractures can adversely affect outcomes. Fracture dislocations were found to have a poorer prognosis than pure hip dislocations [32].

The authors in some reports have attempted closed reduction, but most authors recommend open reduction. Indications for open reduction include a nonconcentric reduction (indicating a retained loose body or significant soft tissue injury preventing proper reduction), associated acetabular or femoral head fracture that will require an open repair, femoral neck fracture, and a dislocation that is not reducible by closed reduction techniques [33]. Timely reduction can reduce long-term complications, such as avascular necrosis of the femoral head, neurovascular injury, or cartilaginous degeneration. The literature suggests that the reduction effect is greater within 6 h after trauma [34]. Blunt chest injury in this patient prevented us from performing hip surgery in a timely manner. Open reduction was performed 5 days after injury, but fortunately, no osteonecrosis of the femoral head was observed during the 5-year follow-up.

The limitations of our study include the following. First, it was a rare case, which limited our ability to identify statistically significant differences in patients’ outcomes and to perform statistical analyses. Second, the patient was discharged during the follow-up of clinical and radiographic evaluation; therefore, there are incomplete or missing data. Finally, longer follow-up is needed to detect complications such as post-traumatic arthritis, avascular necrosis of the femoral head, and heterotopic ossification formation. Despite these limitations, our case report is of great research interest.

Femoral head anterior dislocation is rare, and the dislocation combined with multiple organ injuries and multiple fractures is even rarer, which makes the reporting of such a case a necessity. By documenting the clinical presentation, management, and outcome of this unique case, the challenges and potential complications associated with femoral head displacement toward the obturator foramen are highlighted to aid the understanding of the risks and benefits involved, to help fill the gap in the literature, and to guide the clinician in proper diagnosis and treatment.

Conclusions

Femoral head anterior dislocation is rare in clinical practice. Concomitant vital organ injuries and limb fractures can be life-threatening. It must be emphasized that treatment can be delayed due to polytrauma. That is why it is crucial to correctly diagnose polytrauma as soon as possible. Treatment of multiple injuries, particularly in older patients, is helpful for reducing the occurrence of complications and sequelae and helping patients recover quickly.