Acetabular Fractures


Incidence

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%.

Fracture patterns

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)

Matta %

(n = 255)

Both columns 27.9 33.3
Transverse with posterior wall 20.6 23.5
Posterior wall 22.4 8.6
T-shaped 5.3 12.2
Transverse 3.7 3.5
Anterior column 3.9 4.7
Anterior column with posterior hemitransverse 8.8 5.9
Posterior column with posterior wall 3.5 3.9
Posterior column 2.3 3.1
Anterior wall 1.6 1.2

Investigations

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

Treatment

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. 

COMPLICATIONS

Nerve Injury

Letournel and Judet reported an 18.4% rate of sciatic nerve injury in their original series of posterior approaches for acetabular fractures.

Heterotopic Ossification

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.

Infection

The Letournel reported an overall incidence of infection over 30 years of acetabular fracture of 4.2%.  Matta reported a 5% incidence of infection

Thromboembolic disease

33% in pelvic veins on one MRI study

61% in patients receiving no prophylaxis

PE in 10%, fatal PE in 2% 

Chondrolysis

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.

Outcomes

Dependent on