Comprehensive Management of Transverse Plus Posterior Wall Acetabular Fractures: A Case Study
Key Takeaway
A Transverse plus Posterior Wall Acetabular Fracture, often from high-energy trauma, involves a fracture line traversing the acetabulum (transverse component) and a significant posterior wall fragment. Diagnosis relies on detailed clinical examination, orthogonal radiographs, and crucial CT scans with 3D reconstructions to characterize fracture displacement, articular involvement, and guide pre-operative planning, especially after hip dislocation reduction.
A 42-year-old male presents following a high-speed RTA. He has a right-sided posterior hip dislocation that has been reduced in the ED. You are presented with the following AP Pelvis radiograph. Describe your systematic approach to evaluating this image and detail the key findings.
Candidate: I would start by checking image quality and patient identification. On the AP pelvis, I see a fracture of the right acetabulum. The ilioischial and iliopectineal lines are disrupted, suggesting a transverse component. There is also a large posterior wall fragment and some superior iliac wing involvement. I would then request Judet views and a CT scan to fully classify the injury and check for marginal impaction.
Candidates often jump straight to the fracture classification ("It's a transverse posterior wall fracture") without a systematic survey. Failing to mention the status of the "teardrop," the "roof arc," or the integrity of the contralateral side shows a lack of structured, safe orthopaedic practice.
Adopt an 'ABC' radiographic approach: 1. Assessment: Confirm film quality, rotation, and pelvic ring integrity. 2. Lines: Systematically trace the five radiographic lines (iliopectineal, ilioischial, teardrop, roof, and anterior/posterior walls). 3. Findings: Identify the disruption of the iliopectineal/ilioischial lines (transverse) and the posterior wall fragment. 4. Urgency: Comment on the state of the joint congruity and the femoral head (specifically regarding hip reduction status). 5. Next Steps: State that CT is mandatory to assess "marginal impaction," which is the critical determinant of prognosis and fixation strategy.
You have decided to proceed with open reduction and internal fixation. What are the specific risks to the sciatic nerve during the Kocher-Langenbeck approach, and how do you mitigate these intra-operatively?
Candidate: The sciatic nerve is at risk from traction or direct injury. I would keep the knee flexed and the hip extended to reduce tension. I'd identify the nerve early and protect it with the obturator internus muscle belly as a cushion, ensuring no retractors are placed directly on the nerve itself.
Forgetting to mention the specific anatomical positioning of the limb (knee flexion/hip extension) or neglecting to mention the danger of the "peroneal division," which is more tethered and susceptible to injury than the tibial division.
Structure the answer into Positioning (prone with knee flexed >60° and hip extended), Identification (early identification, vessel loop handling without tension), and Protection (using the obturator internus reflection as a soft-tissue "buffer"). Acknowledge that the peroneal division is at higher risk due to its lateral position and relative lack of mobility at the sciatic notch.
During the procedure, you observe marginal impaction of the posterior rim on the CT scan. How does this alter your surgical technique, and what is the consequence if this is ignored?
Candidate: Marginal impaction means the articular cartilage is crushed into the underlying bone. I must elevate these fragments anatomically. If I ignore them, the joint will remain incongruent, leading to rapid post-traumatic arthritis.
Failing to mention the need for bone grafting. Simply elevating the cartilage isn't enough; the resulting "void" in the cancellous bone must be structurally supported with graft, or it will subside.
Explain that marginal impaction is a "non-reducible" fracture component if treated like a standard cortical fracture. The technique requires (1) Visualization: distracting the femoral head, (2) Elevation: using a small osteotome to lever up the impacted cartilage, (3) Grafting: filling the subchondral void with autograft/allograft to provide structural support, and (4) Buttressing: fixating the posterior wall over the reconstructed articular surface. Ignoring this leads to persistent joint incongruity and "centralized" cartilage wear.
