A Rare Case : Traumatic Posterior Hip Dislocation Associated with Anterior Column and Incomplete Posterior Column Acetabular Fracture

Introduction: The hip is among the most solid joints within the human body that took a lot of force to dislocate it. Hip dislocation is frequently associated with acetabulum fracture. Although traumatic posterior hip dislocation is rarely involved anterior column fracture. Case Presentation: We describe a rare case of traumatic posterior dislocation of hip associated with anterior column and incomplete posterior column acetabular fracture in a young female following road traffic accident. The patient hip dislocation was reduced with closed reduction and perfomed open reduction and fixation under C-Arm for acetabular fracture management. Assessment of anterior and posterior acetabular column was revealed stable after fixation. The goals are to maximize the patient's ability to function, enable early recovery to function. The patient was able to flex her left hip at 6 weeks after the surgery. Conclusion: This case highlights a rare case of the traumatic posterior hip dislocation associated with anterior column and incomplete posterior column acetabular fracture, attempts to elucidate the mechanism of injury and perform prompt reduction to achieve a better patient outcome.


INTRODUCTION
The hip is among the most solid joints within the human body. It took a lot of force to dislocate the hip that commonly resulted after a high-energy trauma. Traumatic hip dislocation majority occur in male young patient that caused by motor vehicle accident. The position and type of dislocation were defined as the direction of the resultant force and lower limb position during the impact 1 . Hip dislocations are classified as anterior, posterior, or central based on where the head of femur is in relation to the acetabulum 7 . The posterior dislocation causes 90% of hip dislocations cases 2 .
Hip dislocation is frequently associated with acetabulum fracture, which can result in increased complications insidence 2,4 . The posterior wall fracture is the most common fracture pattern of posterior hip dislocation among all acetabular fractures 4 . Traumatic posterior hip dislocation is rarely involved Anterior column fracture. We describe a rare case of traumatic posterior dislocation of hip associated with anterior column and incomplete posterior column acetabular fracture.

CASE PRESENTATION
A 24 years old female was involved in road traffic accident between a motorcycle and three-wheeler vehicle and threw herself in the gutter after accident. She was taken to the emergency department of the district hospital and then to be referred to Prof. Dr. Margono Soekarjo Hospital. Patient suffered traumatic brain injury with loss of consciousness which is being treated by neurosurgeon. The patient consulted to orthopaedic department after being treated by neurosurgical department because there was shortening and limitation of movement of the left limb, then the patient transfered to the orthopaedic department for proper management. Physical examination findings are patient in altered conciousness with 11 score of Glasglow Coma Score and hemodinamically stable. Hip examination revealed shortening, flexed, adduction, internal rotation of the left limb [ Figure 1]. The patient underwent an anteroposterior pelvic radiograph, the results showed that the head of the left femur protruded from the acetabulum and visible fractures in the anterior column of the acetabulum, fracture of the inferior \ ramus of the pubic bone [ Figure 2]. This patient was initially diagnosed with posterior dislocation of the left hip with an anterior column acetabular fracture. The patient then underwent investigation with CT Scan of Pelvic, it revealed superoposterior dislocation of left hip with anterior column acetabulum fracture, incomplete posterior column fracture and inferior pubic rami fracture [ Figure 3].

Figure 2. Pre Operative Pelvic AP View
Surgical treatment was planned for patient. Preoperative antibiotic with 2 gr of Cefazolin was given for prophylaxis. Under general anesthesia patient lied in supine position. Closed reduction of hip with Allis Manuever was performed for dislocated hip. Illioinguinal approach was utilized for expose into the fracture site. Intraoperatively, open reduction and internal fixation of anterior acetabular column was performed with a reconstruction plate and cortical screws under C-Arm imaging [ Figure 4]. Assessment of anterior and posterior acetabular column was revealed stable after anterior fixation. The wound was irrigated with normal saline then closed with a suction drain. Skin traction was applied in the left limb to maintain reduction. Corresponding Author: Affan Sodiq Sabda Prayoga  After the surgical treatment, pelvic radiographs were taken to assess the quality of the reduction. [ Figure.5]. The patient was also evaluated by a neurosurgeon before being discharged as the patient still had impaired consciousness. The patient was followed up in the clinic, 6 weeks after the surgery the patient was able to flex her left hip [ Figure.

DISCUSSION
One of most solid joints in the humam body is the hip. Hip joint is unlikely to dislocate with a thick joint capsule and strong muscular structure support. It requires high energy trauma to dislocate the hip. Traumatic dislocation can be divided into two types, simple dislocation without associated fracture and complex dislocation associated with fracture 1,2 .
The resultant force direction and the position of the hip influence hip dislocation. Posterior hip dislocation contributes to 90% of hip dislocation cases. Anterior wall fractures are generally associated with anterior hip dislocations, while posterior wall injuries are associated with posterior hip dislocations 9 . A posterior hip dislocation uncommonly involves an anterior wall fracture.
Hip dislocation after motor vehicle accident has high insidence of nonorthopedic additional injuries with closedhead injuries (24%), craniofacial fractures (21%), thoracic injuries (21%), and abdominal injuries (15%) 1 . We describe rare case of 24 yeas old female with posterior dislocation of hip that involved anterior column acetabular fracture and incomplete posterior column acetabular fracture also had additional traumatic brain injury following road traffic accident involving a motorcycle and three-wheeler. Combinations of cases above suggest some variable mechanism of injury. Typically posterior dislocation of hip occured by intensive axial forces impact to the hip while flexed and adducted and internal rotated that lead posterior dislocation of the hip and posterior acetabulum fracture 1 . In our patient, we believe that the mechanism causing the rare fracture dislocation pattern was dynamic axial force to femur in extension, external rotation, and abduction that caused anterior acetabular column fracture. Although before an anterior hip dislocation could occur, there was likely a change in direction of the actuating force when the patient encountered the gutter and forced the left hip in flexion and adduction causing the posterior hip dislocation.
The surgical approach is one of the most important components for an optimally suitable surgical technique. The ilioinguinal approach is applicable to all fractures involving anterior acetabular fracture, T-shaped fracture, bicolumnar fractures with minimal posterior column comminution 7,8 . The surgical approach is selected taking into account the type of fracture, the extent and location of fracture displacement, the amount of time that passes between the injury and the surgical intervention 7 . This patient had an anterior column and an incomplete acetabular fracture of the posterior column with impaired consciousness during surgery. The ilioinguinal approach was chosen in this case after performing a hip reduction using the Allis maneuver. Anterior and posterior acetabular column assessment under C-Arm was stable after anterior fixation. A single surgical approach is used in hopes of reducing and fixing the fracture in one go.
The postoperative outcome of an acetabular fracture shows variable results. The goals are to maximize the patient's ability to function, enable early recovery to function, and quickly identify and address problems. The patient should be actively mobilized in 6-12 weeks 7 . In this case, the patient is able to flex the hip 6 weeks after the surgery.

CONCLUSION
This case highlights a rare case of the traumatic posterior hip dislocation associated with anterior column and incomplete posterior column acetabular fracture, attempts to elucidate the mechanism of injury and perform prompt reduction to achieve a better patient outcome.