Acetabulum Fracture Posterior Wall Fracture - Everything You Need To Know - Dr. Nabil Ebraheim

Описание: Dr. Ebraheim’s educational animated video describes posterior wall fractures of the acetabulum.

The posterior wall fracture is the most common acetabular fracture.
It can be a simple fracture, associated with dislocation of the femoral head, or rarely, associated with a Pipken fracture. Pipken fracture includes a simple fracture plus a fracture of the femoral head.
Posterior wall fractures can also be associated with transverse fracture or a posterior column fracture.
The fixation is always done posteriorly. If there is a large posterior wall fracture associated with other fractures, you must go posteriorly to fix the posterior wall.
A posterior wall fracture can be seen in the obturator view. The obturator view is done with the involved hip up 45 degrees. The anterior column can also be seen in the obturator view. So, if you see the posterior wall, you can see the anterior column. The displacement of the fracture can also be seen in the obturator view (Gull sign).
Marginal impaction is more common in posterior acetabular wall fractures and it should be recognized and corrected because it can lead to hip instability. CT scan is the study of choice, as you will see the marginal impaction of the acetabulum on the CT scan.
Some pieces of the articular cartilage of the acetabulum will be impacted into the underlying cancellous bone in a non-anatomic position. The marginal impaction is identified in up to 25% of posterior fracture dislocations requiring open reduction.
If the fracture of the posterior wall is comminuted, then the incidence of arthritis will be high.
The size of the posterior wall fracture has an effect on the stability of the hip joint.
Some believe that the size of the posterior wall fragment is not a reliable indicator for instability of the hip.
If the hip is dislocated, hip reduction should be done urgently to minimize the incidence of avascular necrosis. CLosed reduction should be done in less than 6 hours. The risk of avascular necrosis depends on the interval between the injury and the reduction of hte dislocation.
In a posterior dislocation of the hip, always check the knee fr injuries such as a dashboard injury.
In hip dislocations, there might be a concern of deceleration injury involving the aorta.
Always check sciatic nerve function. The peroneal division of the sciatic nerve could be affected. Check for foot drop or sensation at the top of the foot.
After closed reduction, when the patient has a posterior wall fracture, assess the stability of the hip, especially if the fragment is small. The hip is usually stable if the fragment size of the acetabulum is less then 20%. Fragment size of the acetabulum more then 40% means the hip is unstable. A fragment size between 20-40% shows the hip stability is undetermined.
Assessment of the stability of the hip is needed . To do so, examination of the patient under general anesthesia utilizing flourscopy is done. From here, look at the obturator view. The hip should be in flexion, adduction, and do axial load. Then, check the medial clear space for an opening. Opening of the medial clear space suggests instability of the posterior wall fracture.
In the case of fracture dislocation, reduce the hip immediately, and then fix the fracture later if the fracture needs fixation.
If there is a posterior wall fracture with marginal impaction:
Pieces of the cartilage are impacted inside the joint.
-Reduce the fracture, life the cartilage, and apply bone graft behind it to support the cartilage pieces. Then add a posterior plate fixation. Keep in mind not to insert screws into the danger zone.
During posterior approach to the hip, keep the knee in flexion and the hip in extension, especially during traction to avoid sciatic nerve palsy.
In comminuted posterior wall fractures, I use buttress plates in order to buttress the multiple fragments and to lock it in place. Then, I use a plate on top of it, like a wall protecting the small plates. We want to make sure that the screws are not penetrating the joint.

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