Preoperative Transcutaneous Oxygen Perfusion Measurements in Predicting Atraumatic Wound Healing After Major Lower Extremity Amputation.

Abstract

This study examined the correlation between preoperative transcutaneous oxygen perfusion (TcPO₂) measurement and the success of wound healing after major lower extremity amputation. There is no validated consensus on how to accurately determine appropriate amputation levels. A TcPO₂ greater than 30 to 40 mm Hg is widely cited as a positive predictor of postoperative wound healing, but its validity has not been well defined. A retrospective chart review was performed for patients who underwent above-knee amputation (AKA), through-knee amputation, or below-knee amputation (BKA) at a single institution from 2012 to 2018 with preoperative TcPO₂ values and a minimum 30-day postoperative clinical follow-up. This review yielded 141 total amputations: 93 BKAs, 6 through-knee amputations, and 42 AKAs. Fifty-five amputations were unsuccessful, defined by postoperative wound dehiscence or infection. Of these, 37 were BKAs, 4 were through-knee amputations, and 14 were AKAs. There was a significant difference in preoperative TcPO₂ between the successful and unsuccessful amputations, at 46.2 and 38.3 mm Hg, respectively (<i>P</i>=.02). A TcPO₂ of 30 to 40 mm Hg showed a 68.8% success rate, and a TcPO₂ of less than 20 mm Hg showed an 18.2% success rate. A receiver operating characteristic curve for TcPO₂ predicting amputation success had an area under the curve of 0.53 for AKAs and 0.61 for BKAs; the diagnostic ability is far from prognostic. There is no linear association between TcPO₂ and success rate. A TcPO₂ of less than 20 mm Hg has a high positive predictive value for failure, but higher levels are not 100% predictive of wound healing success after amputation, as previously reported. [<i>Orthopedics</i>. 2022;45(3):174-180.].