The Use of Transcutaneous Oximetry to Predict Healing Complications of Lower Limb Amputations: A Systematic Review and Meta-analysis

ObjectiveTo determine the validity of transcutaneous oximetry (TcPO2) as a predictor of lower limb amputation healing complications.DesignA systematic review and meta-analysis.MethodsWe searched five major medical databases, relevant review articles and reference lists and included all studies that evaluated TcPO2 for its ability to predict lower limb amputation healing failure. We selected eligible articles and conducted data abstraction independently and in duplicate.ResultsThirty-one studies, enrolling 1824 patients with 1960 amputations, met our inclusion criteria. Only one study reported undertaking a multivariable analysis, which demonstrated that a TcPO2 level below 20 mmHg was an independent predictor of re-amputation occurrence (adjusted odds ratio (OR) 3.08, 95% confidence interval (CI) 1.19–7.98). Fourteen prospective cohort studies reported data that allowed for the calculation of an unadjusted relative risk of lower limb amputation healing complications leading to amputation revision associated with a TcPO2 level below cut-offs of 10 mmHg (1.80; 95% CI 1.19–2.72), 20 mmHg (1.75; 95% CI 1.27–2.40) 30 mmHg (1.41; 95% CI 1.22–1.62) and 40 mmHg (1.24; 95% CI 1.13–1.39).ConclusionsThis review suggests that TcPO2 predicts healing complications of lower limb amputations. A value of less than 40 mmHg results in a 24% increased risk of healing complication compared to over 40 mmHg and the risk further increases as the TcPO2 decreases. There is, however, insufficient evidence to judge whether this tool adds important information beyond clinical data or to suggest an optimal threshold value. There is a need for a large, sufficiently powered study that adjusts for appropriate clinical variables.