Although hip dislocation combined with acetabular fracture is not an uncommon injury, anterior acetabular wall fractures rarely occur in patients who have posterior fracture-dislocations of the hip. This article presents a unique case of anterior and posterior wall fractures of the ipsilateral acetabulum in a patient who sustained traumatic posterior hip dislocation that resulted from a high-speed motor vehicle accident. The initial imaging evaluation, which did not include the obturator oblique view, revealed no concomitant anterior acetabular wall fracture. Repeated manipulative reductions were unsuccessful in reducing the displaced hip joint. Pelvic computed tomography (CT) scans revealed the initially missed anterior acetabular wall fracture fragments incarcerated in the left hip joint in addition to the hip dislocation and the posterior acetabular wall fracture. The incarcerated bone fragments lay between the anterior wall and the femoral head, and between the posterior wall and the femoral head, which appeared to derive from both anterior and posterior acetabular walls, respectively. Open reduction and internal fixation was performed to manage the posterior dislocation and associated acetabular fractures. Intraoperatively, the major anterior wall fragment was used to reconstruct the defected posterior wall. This case highlights the necessity of suspicion and pre- and postoperative monitoring of the obturator oblique view and CT scans to detect the potentially existing anterior acetabular wall fracture. Early surgical intervention is important to guarantee satisfactory outcomes of such complex fracture-dislocation injuries.
Traumatic hip dislocation accounts for 2% to 5% of all dislocations.1 The majority is posterior hip dislocation. Hip dislocation is a severe injury with the potential for significant complications and long-term patient morbidity. Hip dislocation combined with acetabular fracture is not an uncommon injury. However, anterior acetabular wall fractures rarely occur in patients who have posterior fracture-dislocations of the hip. This article presents a rare case of posterior hip dislocation with fractures of both the posterior and the anterior acetabular wall.
A 23-year-old man was injured in a motorcycle/automobile accident. The patient was driving a motorcycle at a high speed with both hip and knee joints flexed at approximately 90° and the thigh rotated externally when he collided with a vehicle approaching from the opposite direction and was struck on the left side of his body. He lost consciousness immediately and sustained severe injury to the head, left upper arm, and left lower extremity.
At presentation, the patient was hemodynamically unstable with a systolic blood pressure of 60 mm Hg, a diastolic pressure of 40 mm Hg, and a heart rate of 140 bpm. His vital signs were beyond normal limits.
Physical examination revealed that the patient was in a coma with bleeding and obvious abnormality of the head, face, eye, nose, and left upper and lower extremities. A shortened, internally rotated, adducted lower extremity in slight flexion was observed. He was diagnosed with traumatic shock and multiple fractures. Initial resuscitation was performed successfully.
Anteroposterior (AP) and iliac oblique radiographs of the left pelvis demonstrated posterior dislocation of the left hip concomitant ipsilateral posterior acetabular wall fracture (Figure 1); fractures of the femoral shaft, intercondyloid eminence, patella, and left humeral shaft; and multiple craniofacial fractures.
Fractures of the left femoral shaft and the humeral shaft were managed with external fixators in the emergency department. Repeated manipulative reductions failed to reduce the displaced hip joint. Pelvic computed tomography (CT) scans revealed anterior acetabular wall fracture fragments incarcerated in the left hip joint in addition to the hip dislocation and the posterior acetabular wall fracture. The incarcerated bone fragments in the hip joint prevented hip manipulative reduction (Figure 1).
The incarcerated bone fragments lay between the anterior wall and the femoral head (Figure 1C) and between the posterior wall and the femoral head (Figure 1D), which appeared to derive from both anterior and posterior acetabular walls, respectively.
Four days after admission, open reduction and internal fixation was performed of the posterior dislocation of the left hip and acetabular fractures via the posterior approach. After dissection, the major fracture fragment and multiple minor fragments were noted among the muscle fiber. Laceration of the joint capsule and the round ligament of femur was observed. The major fragment from the anterior acetabular wall was removed. The femoral head was inspected for further dislocation and the articular cartilage showed some chondral defects in the posterior aspect. The fracture fragments incarcerated in the hip joint were removed. The femoral head was reduced.
Although the posterior wall was constructed with its own major fragment, there was apparent bone defect left in the posterior wall because of comminuted fracture. The posterior wall defect was repaired with bone graft removed from the anterior acetabular wall (Figure 2A). Temporary fixation with K-wires was achieved and definite fixation with reconstructed titanium plate was performed (Figure 2B).
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Figure 2: The major fragments from the anterior and posterior walls were used to reconstruct the posterior wall (A). Reconstructed titanium plate was applied to achieve definitive fixation (B).
Postoperative radiographs and CT scans showed nearly anatomical reduction of the left acetabular fracture (Figure 3). The postoperative course was uneventful. Supervised early exercise of injured limbs without weight bearing was encouraged as the pain subsided. Partial weight bearing was started at 10 weeks and progressed to full weight bearing at 28 weeks postoperatively based on clinical and radiological evidence of healing.
Repeat imaging evaluation at follow-up demonstrated satisfactory alignment of the bony structures. The fractures consolidated uneventfully. At 22 months postoperatively, the patient had nearly normal walking capability but reported minor hip pain occasionally, which could be controlled with drugs.
Posterior dislocations make up approximately 90% of hip dislocations caused by traumatic series.2 However, posterior dislocation of the hip joint with associated acetabular fracture is an uncommon, severe injury. The rare injury pattern of the hip joint in the present case featured the concomitant fractures of both anterior and posterior walls of the ipsilateral acetabulum and the bone fragments from the walls incarcerated in the hip joint, which resulted in the failure of multiple attempts at reduction of the dislocated hip.
A thorough review of both the English and Chinese literature yielded few reports on the injury pattern of posterior hip dislocations concomitant both anterior and posterior wall fractures of the ipsilateral acetabulum. Fragmentary bone incarceration after acetabular fracture with hip dislocation is also uncommon and estimated to occur in only 2.9% to 8% of cases.3-5 The fragments’ incarceration in the joint after acetabular fractures could be a severe injury even without the hip dislocation. The incarceration likely occurred after partial posterior hip dislocation, which reduces spontaneously.6
It is rare to find the bone fragments incarcerated in both the anterior and posterior part of the hip joint, which warrants special precaution to reestablish the joint congruity by removing any residual fragment from the hip joint during surgery. This injury pattern was an unusual type of hip and acetabular injury that does not fit in any current classification system.7-10
The injury mechanism of the present case was complex in nature. The patient was operating a motorcycle at a high speed with both hip and knee joints flexed and the thigh rotated externally when the collision occurred. The left lower extremity, especially the left knee joint, received a large load of frontal and adduction force simultaneously. The dislocation caused by a longitudinal compression force combined with adduction force is the first incident in this combined type of hip injury. If the longitudinal forces are stronger than the adduction forces, a posterior wall acetabular fracture is produced.11 At the same time, the violent adduction force compressed the femoral neck onto the anterior brim of acetabulum, which led to the anterior wall fracture. During the course of posterior dislocation, the anterior capsule and surrounded soft tissue were dragged posteriorly and fragments of the anterior wall were pulled back and incarcerated into the hip joint. There was a tendency for the posterior dislocated femoral head to reduce partially and spontaneously due to the traction of the muscle and capsule when the collision stopped. As a result, the bone fragments from the posterior wall were pulled as the femoral head was partially reduced and eventually stuck in between the posterior acetabular wall and the femoral head. In addition to this complex injury, the violent force also caused multiple fractures on the head and upper and lower extremities, as well as soft tissue injuries.
The diagnosis of posterior hip dislocation and associated posterior acetabular wall fracture can be typically established on plain AP and iliac oblique radiographs. Since the abnormality of the injured hip apparently indicated posterior dislocation of the hip, the obturator oblique radiograph, which could reveal the fracture of the anterior wall, was not taken because the anterior acetabular wall fracture was not suspected at the initial evaluation. However, after a few failed attempts at close reduction of the hip, the presence of intra-articular fragments was suspected. Computed tomography scans subsequently confirmed the anterior acetabular wall fracture, evident by the presence of the incarcerated bony fragments.
Although the combination of the anterior acetabular wall fracture and posterior dislocation of the hip is rarely seen in practice, misdiagnosis, under-recognition, or underreporting may account for the lower incidence of such injury. The insidious nature of the initially missed anterior acetabular wall fracture requires a high index of suspicion and routine monitoring of the acetabulum by the obturator oblique radiograph and CT scans pre- and postoperatively.
Special attention should be paid to observe the obturator oblique radiograph because the fragment could be incarcerated in the hip joint and may not be clearly revealed. Intraoperative detection of the anterior acetabular wall should be performed in high-risk patients with multiple traumas sustained in a high-energy accident.
Traumatic posterior hip dislocation requires early reduction to prevent complications. Common complications of hip dislocation include avascular necrosis of the femoral head, posttraumatic arthritis,12 and sciatic nerve injury.13 Other potential complications include heterotopic ossification, deep vein thrombosis, and limitation of hip movements.14 Failure to detect and appropriately treat an acetabular fracture may lead to significant complications.15
Open reduction and internal fixation of the hip dislocation is often required in cases with associated acetabular fractures to prevent the recurrence of the dislocation and minimize functional limitations, or in cases with failed closed reduction or if the sciatic nerve must be explored.1 Surgical intervention is also required in cases with bone fragments in the joint space, just as the present case described. In the present case, the surgical intervention for the patient was delayed 4 days due to his critical condition resulting from concomitant traumatic shock. Intraoperatively, the comminuted fragments from the posterior wall were not used to reconstruct the posterior wall since they were difficult to hold in position and might fall back in the hip joint. The posterior wall defect was observed after the major fragment was reduced and fixated temporarily on the posterior wall. The major fracture fragment removed from the anterior acetabular wall was used to graft the defect of the posterior wall to improve the rigidity. To minimize the risk of developing early-onset degenerative hip disease, no more than 1 to 2 mm of displacement of the reduced acetabulum was achieved intraoperatively.16
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- Duquennoy A, Senegas J, Augereau B, et al. Fractures of the acetabulum. Results 5 years later. Round table [in French]. Rev Chir Orthop Reparatrice Appar Mot. 1982; 68(suppl 2):45-82.
- Letenneur J, Fleuriel M, Sanguy D, et al. Intra-articular bony incarceration after reduction of dislocated hip. Diagnostic and therapeutic problems (author’s transl) [in French]. J Chir (Paris). 1978; 115(2):97-100.
- Judet R, Judet J, Letournel E, Vacher D. Fragmentary incarceration in cotyloid cavity fractures [in French]. Presse Med. 1968; 76(9):411-414.
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- Selvey DM, Siboto GM. Classification of posterior fracture dislocation of the hip joint: a modification of the Thompsen Epstein classification. Injury. 2001; 32(3):217-219.
- Goddard NJ. Classification of traumatic hip dislocation. Clin Orthop Relat Res. 2000; (377):11-14.
- Thompson VP, Epstein HC. Traumatic dislocation of the hip; a survey of two hundred and four cases covering a period of twenty-one years. J Bone Joint Surg Am. 1951; 33(3):746-778.
- Pipkin G. Treatment of grade IV fracture-dislocation of the hip. J Bone Joint Surg Am. 1957; 39(5):1027-1042.
- Duygulu F, Calis M, Argun M, Guney A. Unusual combination of femoral head dislocation associated acetabular fracture with ipsilateral neck and shaft fractures: A case report. J Trauma. 2006; 61(6):1545-1548.
- Upadhyay SS, Moulton A, Srikrishnamurthy K. An analysis of the late effects of traumatic posterior dislocation of the hip without fractures. J Bone Joint Surg Br. 1983; 65(2):150-152.
- Dudkiewicz I, Salai M, Horowitz S, Chechik A. Bilateral asymmetric traumatic dislocation of the hip joints. J Trauma. 2000; 49(2):336-338.
- Sahin O, Ozturk C, Dereboy F, Karaeminogullari O. Asymmetrical bilateral traumatic hip dislocation in an adult with bilateral acetabular fracture. Arch Orthop Trauma Surg. 2007; 127(8):643-646.
- Mann CF, Rebollo MI. Femoral neck fracture complicating a missed acetabular fracture in an elderly patient. Injury. 1998; 29(1):75-76.
- Swiontkowski MF. Fractures and dislocations about the hips and pelvis. In: Green NE, Swiontkowski MF, eds. Skeletal Trauma in Children. Vol 3. 4th ed. Philadelphia, PA: Elsevier; 2008:371-374.
Drs Chen, Su, Zhang (Yingze), Zhang (Qi), Zheng, and Pan are from the Department of Orthopedic Surgery, the Third Hospital of Hebei Medical University, Hebei, China.
Drs Chen, Su, Zhang (Yingze), Zhang (Qi), Zheng, and Pan have no relevant financial relationships to disclose.
Correspondence should be addressed to: Jinshe Pan, MD, Department of Orthopedic Surgery, the Third Hospital of Hebei Medical University, No. 139 Ziqiang Rd, Shijiazhuang, Hebei 050051, China.