Background: There are various sites for pin placement in the pelvis. Recent studies have suggested that the supra acetabular pin placement is mechanically stronger and has been recommended as an alternative. The aim of this study is to analyse the morbidity of the most commonly used pin placement sites namely, conventional pin placement into the anterior iliac crest versus the low pin placement into the supra acetabular region.

Methods: Sixty one patients who required pelvic external fixation as part of their management between April 1998 and December 2001 were identified. Three patients died and were excluded from the study. Of the remaining 58 patients, 33 were treated with a supra-acetabular external fixator and 25 had an iliac crest external fixator. The majority of patients sustained the pelvic fracture as a result of road traffic accident. There were no statistically significant differences in the number of patients, mean age, length of stay, ISS or type of fractures for the two patient groups.

Results: Fewer complications were noted in the supra-acetabular group versus the iliac crest group (21.2% vs. 56.0%, p< 0.05). In particular, infection rates were significantly lower in the supra-acetabular group (15.1% vs. 36%, p< 0.05). There were no significant differences between the two groups in the number of pin cut-outs or misplacements, injury to the lateral femoral cutaneous nerve or loss of reduction.

Conclusion: The supra-acetabular technique of pin insertion for pelvic external fixation has fewer complications and should be utilised if an image intensifier is available. The lower rate of pin tract infection is a favourable outcome when secondary pelvic reconstructive procedures are necessary.