Preoperative assessment of 180-day outcomes after first tibial transverse transport for severe diabetic foot ulcers

Patients with severe diabetic foot ulcers need preoperative estimates of recovery, survival and limb preservation. We develop a six-predictor score for healing or persistent non-healing with survival and limb preservation, or ipsilateral below-knee amputation or all-cause death, within 180 days after first tibial transverse transport. Development includes 423 consecutive patients and external validation includes 213 patients from three centres. Among 205 patients with complete inputs, the severe-outcome area under the receiver operating characteristic curve is 0.895 (95% confidence interval 0.803–0.963). Compared with a four-predictor reference, the score reduces overall three-outcome probability error but increases severe-outcome probability error. Mean predicted severe risk is 15.0%, compared with 5.9% observed. Here, we show that combined local and systemic assessment provides quantitative prognostic information across distinct recovery outcomes, while external risk overestimation establishes the need for local recalibration.