Determinants and estimation of healing times in diabetic foot ulcers.

AIMS: To assess the wound size reduction and time course for healing and to establish equations to predict the time course of wound healing in neuropathic, neuroischemic, and ischemic diabetic foot ulcers.
METHODS: This prospective study evaluates wound healing over at least a 10-week period in 31 Type 1 or Type 2 diabetic patients with plantar foot ulcers. Thirteen consecutive diabetic patients with neuropathic foot ulceration, 10 consecutive diabetic patients with neuroischemic ulceration, and 8 diabetic patients with peripheral occlusive vascular disease were selected for the study. All patients received identical ulcer wound care including use of proper footwear, non-weight-bearing limb support, use of appropriate antibiotics, debridement, tight control of serum glucose levels, and careful monitoring of the ulcer. Ulcer healing was assessed by planimetric measurement of the wound area every second week until wound healing. The time course of wound healing was calculated by the daily wound radius reduction.
RESULTS: The wound area (mean+/-S.E.) in the patients with neuropathic foot ulceration was 61.2+/-17.1 at the beginning and 3.2+/-1.5 mm(2) after 70 days (P=.005). The wound radius decreased by 0.045 mm (95% confidence interval [CI] 0.039-0.055) per day, with most of the wound healing being achieved between the first and seventh week of ulcer care. The average healing time was 77.7 (95% CI 62-93) days. In the neuroischemic group, the initial average wound area was 26.6+/-7.0 mm(2), and 6.25+/-1.7 mm(2) after 10 weeks (P=.007). The wound radius reduction was 0.019 mm/day (95% CI 0.017-0.023) with an average healing time of 123.4 (95% CI 101-145) days. The diabetic patients with peripheral occlusive vascular disease had an average wound size of 32.6+/-13.1 at the beginning and 23.9+/-10.7 mm(2) after 70 days of ulcer care (P=.06). The daily wound radius reduction was 0.0065 mm (95% CI 0.0039-0.0091). Average ulcer duration was 133 (95% CI 116-149) days, but three of eight patients achieved no wound healing.
CONCLUSIONS: Providing standard care, the time course of wound healing in diabetic foot ulcers is predominantly determined by etiologic factors, and less by wound size. Taking wound etiology and wound radius into account, the expected healing time can reliably be estimated in neuropathic and neuroischemic ulcers.