The distal blood pressure predicts healing of amputations on the feet.

The healing of digital and transmetatarsal forefoot amputations was compared with the systolic digital and ankle blood pressure, both measured with a strain-gauge, and with the skin perfusion pressure on the forefoot measured with the isotope washout technique. In 85 out of 134 legs (63 per cent) the amputation healed. The frequency of healing correlated statistically significantly with all three measures of distal blood pressures, the closest correlation being with the systolic digital blood pressure (SDBP). As measured in 110 cases the healing rates were: SDBP less than 20 mm Hg: four out of 23; SDBP 20-29 mm Hg: 13 out of 22; SDBP greater than or equal to 30 mm Hg: 51 out of 65. Ankle pressures and skin perfusion pressures were less useful. Invasive infection was present in 40 out of 102 diabetic legs and, next to ischaemia, was the major determinant of the healing results.