Fractures of the acetabulum usually occur as a result of high-velocity injury and often affect the young
Studies at level I trauma centers have shown an admission rate for pelvic and acetabular fractures of 0.5-7.5%.
The femoral head acts like a hammer and is the last link in the chain of forces transmitted from the greater trochanter, knee, or foot to the acetabulum. The position of the femur at the time of impact and the direction of the force determine the type and displacement of the fracture.
|Fracture type||Letournel, %
(n = 567)
(n = 255)
|Transverse with posterior wall||20.6||23.5|
|Anterior column with posterior hemitransverse||8.8||5.9|
|Posterior column with posterior wall||3.5||3.9|
Xrays: AP, obturator oblique, iliac oblique (Judet views)
CT scan- provides additional information, e.g. on bony fragments within the joint space, cartilage fragments which can be inferred from joint space widening, & 3D reconstruction which can allow removal of the femoral head from the picture to simplify things
In a young, healthy patient, open reduction and internal fixation (ORIF) may be appropriate. In an older patient with severe femoral head damage, ORIF with a concomitant total hip arthroplasty may be best. Furthermore, either traction or full weight bearing may be selected for nonoperative management. The ultimate decision is based not only on a detailed analysis of the fracture but also on the patient’s overall health, associated injuries, and the surgical risks.
The desirability of surgery is based on its ability to restore hip joint stability and congruity of the weight-bearing acetabulum.
- Scitaic nerve- 30% Thirty percent of acetabular fractures have associated sciatic nerve injury. The peroneal division is injured most commonly, but both divisions can be involved. Partial injuries increase the risk that the nerve will be injured during surgery.
Letournel and Judet reported an 18.4% rate of sciatic nerve injury in their original series of posterior approaches for acetabular fractures.
- Femoral nerve injury is rare either from the injury or surgery.
- The superior gluteal nerve is vulnerable in the greater sciatic notch, where it may be injured during trauma or during surgery, resulting in paralysis of the hip abductors, creating a major disability.
- The pudendal nerve can be compressed on the traction table, but it usually recovers.
- lateral femoral cutaneous nerve is commonly stretched or cut during anterior approaches. The patient usually tolerates the sensory loss on the lateral aspect of the thigh but should be warned preoperatively about the likelihood of it occurring.
Matta reported a 9% incidence of significant heterotopic ossification without prophylaxis. Johnson et al. however, reported a 62% incidence of Brooker grade III or IV heterotopic ossification for extended iliofemoral approaches when no prophylaxis was used.
The Letournel reported an overall incidence of infection over 30 years of acetabular fracture of 4.2%. Matta reported a 5% incidence of infection
33% in pelvic veins on one MRI study
61% in patients receiving no prophylaxis
PE in 10%, fatal PE in 2%
Chondrolysis after acetabular trauma can occur with or without surgical intervention. Without surgical intervention, it is usually a manifestation of early osteoarthritis. After open reduction and internal fixation, the surgeon must suspect infection or the presence of metal in the joint. Occasionally, avascular necrosis of acetabular fragments causes early collapse and chondrolysis may ensue.
- Timing of Intervention- Fractures treated after 21 days are more difficult to reduce & have poorer outcomes. If anatomical reduction was achieved 90% of patients had a good result, but this ideal was achieved in only 74% of cases. At a 20-year followup 28 of 35 cases initially graded as excellent remained excellent
- Type of Fracture- In Matta’s study the outcomes were related to the type of fracture
- Posterior wall fractures- Posterior wall fractures can often be anatomically reduced but the results do not reflect this eg 94% of Letournel’s posterior wall fractures were anatomically reduced but only 82% had a good or excellent result. Many posterior wall fractures are associated with posterior hip dislocations, & these have a high rate of AVN
- Age of Patient. Older patients (>40) have a lesser chance of an anatomical reduction
- Abductor strength- related to the approach; ilioinguinal approaches (89% normal abductors) were better than Kocher-Langenbeck (85%) & extended iliofemoral (66%)