Major amputation of lower extremity: prognostic value of positive bone biopsy cultures.

BACKGROUND

To assess the correlation between culture results of section's osseous slice biopsy (SOB) and the distal infected site responsible for the amputation performed concomitantly during major amputation of lower extremity. The influence of a positive culture of SOB on the patients' outcome was also evaluated.

MATERIALS AND METHODS

We conducted a retrospective study of medical charts of patients who underwent SOB during major amputation of lower extremity at our institution from 2000 to 2009.

RESULTS

Fifty-seven patients (42 males/15 females, mean age 52.16years) who undergone major limb amputation (47 below knee and ten above knee) were included. The initial medical conditions of the investigated patients were: trauma (n=32), infection (n=13), trophic disorders (n=10) and tumor (n=2). The major cause of amputation was an uncontrolled infection, accouting for 64.9% of the cases (37/57) (foot=5, ankle=8, leg=24), the remaining 20 patients had trophic disorders of lower limb. Twenty-one (36.8%) from 57 biopsies were sterile, 12 (21.1%) doubtful and 24 (42.1%) positive. Thirty-one (54.4%) patients had an antibiotic-free interval before limb amputation. Independently of the bacterial species, 69.6% of the microorganisms identified from SOB were found in the distal infected site. Patients with positive SOB had a significantly longer interval between the decision to amputate the patient and the surgical procedure (200.2 vs. 70.1days; P<0.03) and a shorter total duration of antibiotic therapy before amputation than patients with negative SOB (3.68 vs. 6.08months; P<0.03). The delay for complete healing was significantly higher in patients with a positive SOB compared with those with a negative SOB (3.57 vs. 2.48months; P<0.03).

CONCLUSION

Our results suggest that the infection may extend from the distal site to the level of amputation in a large proportion of cases and that the delay with which the amputation is performed after the decision has been taken may play a role in this event.

LEVEL OF EVIDENCE

Study level IV: retrospective observationnal study.