Review Question - QID 3955

One advantage of supra-acetabular external fixator pins is that they do not interfere or contaminate future approaches to the pelvis or acetabulum involving the lateral window.

In multiply injured patients with pelvic trauma external fixation of the pelvic ring is a valuable tool to assist with resuscitation. Pelvic external fixation should be applied rapidly and allow full access to the abdomen for general surgery intervention. Regardless of the technique used, a pelvic external fixator should form a stable construct that minimizes motion of fracture surfaces and allows for clot formation.

Haidukewych et al evaluated the safety of supra-acetabular pin placement in a cadaveric study. The authors found that the lateral femoral cutaneous nerve (LFCN) was most at risk during pin placement.

Figure A demonstrates a widely displaced symphyseal dislocation with associated bilateral sacroiliac (SI) dislocations (APC 3). Illustration A demonstrates an outlet radiograph of a supra-acetabular external fixtator in conjunction with posterior pelvic ring fixation for an LC3 pelvic ring injury. Illustration B is an illustration of iliac crest external fixation. The video demonstrates techniques for application of both supra-acetabular and iliac crest external fixation pins.

Incorrect Answers:
Answer 2: There has not been a difference demonstrated with pin tract infection between supra-acetabular and iliac crest pins
Answer 3: Both techniques have a risk of malreduction
Answer 4: Theoretically supra-acetabular pins may better control the posterior ring as they may be advanced to the posterior ilium (PSIS) if placed appropriately
Answer 5: Neither type of pin placement or frame should interfere with laparotomy