Intraoperative Ischemia Threshold and Outcomes of Emergency Vascular Repair During Orthopaedic Arthroplasty: A Time-Critical Analysis from a Dedicated On-Call Vascular Service

Background: Intraoperative vascular injuries during elective hip and knee arthroplasty are uncommon but limb-threatening complications. Real-world evidence on emergency on-call vascular management in this setting remains limited. We aimed to identify the intraoperative ischemia time threshold associated with progression to a more severe ischemic presentation (Rutherford IIb) at vascular consultation, in order to support early multidisciplinary activation and prevent irreversible ischemic limb damage. As a secondary aim, we described the clinical spectrum, treatment strategies, and 30-day outcomes of patients managed by a 24 h on-call vascular service (in-hospital coverage during working hours, formal on-call rota out of hours). Non-ischaemic events recorded in the series (e.g., isolated venous injuries and haemorrhagic complications) are documented as part of the overall clinical spectrum but were not the subject of specific time-related analysis. Methods: Single-centre retrospective analysis of 33 consecutive patients undergoing emergency vascular intervention for vascular injury during elective total knee (TKA) or total hip arthroplasty (THA) at a tertiary orthopaedic referral centre in Milan, Italy (January 2023—December 2025). The primary analytical objective was to identify the intraoperative ischemia time threshold associated with Rutherford IIb presentation at vascular consultation; 30-day limb salvage was the primary clinical outcome. Secondary outcomes included technical success, primary 30-day patency, postoperative ankle–brachial index (ABI), length of stay, and Clavien–Dindo complications. Non-ischaemic events (including isolated venous injuries and haemorrhagic complications) are documented as part of the clinical spectrum but were not subject to specific time-related analysis. Receiver operating characteristic (ROC) analysis assessed the discriminative role of intraoperative ischemia time for a Rutherford IIb presentation; univariate logistic regression explored predictors of postoperative complications. Results: Thirty-three patients (mean age 76.3 ± 6.3 years; 54.5% female; ≥2 comorbidities in 81.8%) underwent emergency vascular repair after TKA (60.6%) or THA (39.4%). Injuries were mixed arteriovenous (54.5%), purely venous (24.2%), or purely arterial (21.2%). Mean call-to-incision time was 45.4 ± 11.3 min. In the 25 ischemic cases, the mean intraoperative ischemia time was 130.4 ± 18.7 min. ROC analysis identified an optimal cut-off of 131 min for Rutherford IIb (AUC 0.851, 95% CI 0.679–0.982; p < 0.001), with sensitivity 81.8% and specificity 85.7%. Median ischemia time was significantly higher in IIb than IIa cases (144 vs. 124.5 min; p = 0.003). Technical success and 30-day limb salvage were 100% (95% CI 89.6–100); mean postoperative ABI 0.89 ± 0.03; primary 30-day patency 88.0% (95% CI 70.0–95.8), with secondary patency 100%. All postoperative complications were Clavien–Dindo grade 1; no Clavien–Dindo ≥ 2 events and no 30-day mortality were observed. Conclusions: A dedicated 24 h on-call vascular service achieves excellent 30-day limb salvage and patency in iatrogenic vascular injuries occurring during arthroplasty. An intraoperative ischemia threshold of 131 min identifies higher-risk presentations and supports rapid multidisciplinary activation in high-volume orthopaedic centres.