Failure of Doppler ankle pressure to predict healing of conservative forefoot amputations

Fifty minor foot and transmetatarsal amputations were studied to assess the reliability of Doppler ankle blood pressure (DABP) and skin blood flow (SBF) to predict healing. The level of amputation was determined solely on clinical criteria. Thirty-six (72 per cent) of the amputations healed. There was no statistical difference between mean DABP in healed 89 +/- 8 mmHg mean +/- s.e.m.) and non-healed (91 +/- 12 mmHg mean +/- s.e.m.) amputations. SBF was assessed by 125I-iodoantipyrine clearance in 28 patients. There was no correlation between DABP and SBF (r = 0.038). SBF in patients with healed amputations was 14.8 +/- 1.2 (mean +/- s.e.m.) ml 100 g-1 min-1 in contrast to SBF of 5.9 +/- 0.3 (mean +/- s.e.m.) ml 100 g-1 min-1 in the patients with non-healing (P less than 0.01). Where the flow was in excess of 8 ml 100 g-1 min-1 healing was always obtained while a flow of less than 7 ml 100 g-1 min-1 was associated with healing failure. These results suggest that DABP should be interpreted with caution as this technique fails as an accurate means of identifying those patients suitable for forefoot amputations. Skin blood flow assessment appears to provide an absolute value for the prediction of healing potential at this level.