Diagnosis

61-B3 Partially stable bilateral compression injury (bilateral AP compression and/or lateral compression)

print
Options
1. 61-B3.1 Bilateral incomplete external rotation injury
2. 61-B3.2 Bilateral posterior arch injuries, one externally rotated, the other internally rotated (LC III)
3. 61-B3.3 Bilateral lateral compression injury

1. 61-B3.1 Bilateral incomplete external rotation injury

Posterior injury

Anterior injury

Posterior injury
Both sides of the posterior arch are involved. The posterior ring injury on each side involves either an:

  • Anterior SI joint disruption
  • Sacral fracture

Anterior injury
The typical anterior arch injury produced by B3.1 injuries is disruption of the pubic symphysis. Less frequently, fractures of the pubis or rami may occur. Anterior widening of the pelvis is evident as increased space between the two pubic bones, or fracture surfaces. Fractures are vertically oriented. (The anterior injury is the same as for 61-B1).

2. 61-B3.2 Bilateral posterior arch injuries, one externally rotated, the other internally rotated (LC III)

"Wind swept deformity"

External rotation injury

Internal rotation injury

Anterior injury

This is an LC-III injury, with significant, but partial, instability bilaterally. Deformity is only rotational. There is no proximal or posterior displacement at the posterior arch injuries.

The pattern reflects a high-energy mechanism. The identifying feature of the B3.2 (LC-III) pelvic ring injury is the “wind-swept” deformity, with one hemipelvis rotated externally and the other internally.

Posterior external rotation (B1-type) injury
External rotation injury will be either:

  • Anterior sacroiliac joint disruption (partial)
  • Incomplete sacral fracture

The externally rotated (APC) side is often the site of significant pelvic venous disruption and hemorrhage.

Posterior internal rotation (B2-type) injury
External rotation injury will be either:

  • Anterior sacral compression fracture (partial)
  • Partial sacroiliac joint subluxation or fracture subluxation
  • Incomplete posterior iliac ring fracture

Anterior injury
Anterior arch injuries are frequently multiple, involving both symphysis and rami.

3. 61-B3.3 Bilateral lateral compression injury

Anterior narrowing

Posterior injury

Anterior injury

Tilt fracture

Both hemi-pelves are internally rotated, and the pelvic ring is narrowed anteriorly.

Posterior injury
Each posterior arch injury will be either

  • Anterior sacral compression fracture (partial)
  • Partial sacroiliac joint subluxation or fracture subluxation
  • Incomplete posterior iliac ring fracture

Anterior injury
The pelvic ring is narrowed anteriorly. The anterior arch injury, which may be unilateral on either side, or bilateral, always includes a set of horizontally oriented fractures. Impaction or overlapping of the anterior injuries is evident, and variable in degree.

Infrequently, marked internal rotation displacement through the pubic symphysis can produce a locked symphysis,  with gross narrowing of the pelvic ring.

Another unusual anterior arch injury produced by internal rotation (lateral compression) is the Tilt Fracture. This involves dislocation anteriorly of one pubic bone with symphyseal disruption and anteriorly angulated ramus fractures.