Decreased National Rate of below the Knee Amputation in Patients with Popliteal Artery Injury

Background: Popliteal arterial injury (PAI) is the second most common infrainguinal arterial injury after femoral artery injury with an incidence < 0.2%. A 2003 analysis of the National Trauma Data Bank (NTDB) reported a below the knee amputation (BKA) rate of 7.1% in patients with PAI as well as higher risk in those with an associated fracture or nerve injury. Given advances in vascular surgical techniques, improved multidisciplinary care, and expeditious diagnosis with computed tomography angiography, we hypothesized that the national rate of BKA in patients with PAI has decreased and sought to identify risk factors for BKA in patients with PAI. Methods: A retrospective analysis of the NTDB was performed from 2007 to 2015. Patients >= 15 years of age with PAI were included and grouped by mechanism of injury (blunt versus penetrating). Interfacility transfers were excluded. The primary outcome of interest was BKA. Univariable and multivariable analyses were performed to identify predictors of BKA in patients with PAI. Results: From 4,385,698 patients, 5,143 were identified with PAI (< 0.2%) with most involved in a blunt mechanism (56.8%). The overall limb loss rate was 5.1% (decreased from 7.1% in 2003, P = 0.0037). After adjusting for covariates, a blunt mechanism (odds ratio [OR] = 3.53, confidence intervals [CI] = 2.49-5.01, P < 0.001) and open proximal tibia/fibula fracture or dislocation (OR = 2.71, CI = 2.08-3.54, P < 0.001) were independent risk factors for BKA in patients with PAI. A combined popliteal vein injury (PVI) did not increase the risk for BKA (P = 0.64). Conclusions: The national rate of limb loss in trauma patients with PAI has decreased from 7.1 to 5.1%. A blunt mechanism of injury as well as proximal open tibia/fibula fracture or dislocation continue to be the independent risk factors for BKA. Confirming a previous report, we found a combined PVI not to be associated with higher risk for BKA. Future prospective research to determine other possible contributing factors such as intraoperative hemodynamics and utilization of vascular shunt and fasciotomy appears warranted.