Use of popliteal brachial pressure index as a predictor of wound healing after below-knee amputations with absent popliteal pulse

Background
A below-knee amputation is a transtibial amputation that involves removing the foot, ankle joint, and distal tibia and fibula with related soft tissue structures. Several factors are used to determine the appropriate level of amputation that ensures proper wound healing.
Aim
The aim of this study was to determine the reliability of using the popliteal brachial pressure index as a predictor of wound healing after below-knee amputations with absent popliteal pulse. Popliteal brachial pressure index is the ratio of systolic blood pressure measured at the popliteal artery to that measured at brachial artery.
Patients and methods
This is a prospective observational cohort study. A total of 58 patients undergoing below-knee amputation secondary to chronic ischemia and peripheral arterial disease between November 2019 and January 2022 in Ain Shams University hospitals were included. The study assessed the popliteal brachial pressure index as a predictor of wound healing in below-knee amputations with absent popliteal pulse. The Fisher exact test, analysis of variance test, and the receiver operating characteristic curve were used, with significance defined as value less than or equal to 0.05.
Results
The study was done on 58 patients, comprising 22 (37.9%) females and 36 (62.1%) males, with age ranged between 48 and 80 years and a mean±SD age of 63.97 ± 6.44 years. Healing was primary in 44 (75.86%) patients, delayed in nine (15.52%) patients, and failed in five (8.62%) patients. The cutoff value of popliteal brachial index (PBI) above which below-knee amputation with absent popliteal pulse can be done with high incidence of primary healing was more than 0.48; this value was statistically reliable (=0.0017). However, the cutoff value of PBI above which below-knee amputation with absent popliteal pulse can be done with prediction of primary or delayed healing was more than 0.43, but it was not statistically reliable (=0.0872).
Conclusion
PBI can reliably be used as a predictor for primary wound healing in patients undergoing below-knee amputation with absent popliteal pulse secondary to chronic limb ischemia.