Local infiltration analgesia with vasoconstrictor in tourniquetless robotic total knee arthroplasty for a solitary kidney patient: a case report

Abstract

Introduction: Postoperative pain control is a critical determinant of patient satisfaction following robotic-assisted total knee arthroplasty (TKA); poor management increases the risk of chronic pain development. Conventional use of a pneumatic or mechanical tourniquet is linked to severe thigh pain and neuromuscular injury. Although robotic assistance optimizes surgical times, clinical practice frequently maintains the intraoperative use of an Esmarch bandage for selective mechanical ischemia. Upon bandage removal, acute pain and reperfusion stress trigger an adrenergic discharge that, in solitary kidney patients, compromises renal plasma flow and elevates the risk of acute kidney injury (AKI). The analgésic margin in this group is narrow due to the intrinsic nephrotoxicity of nonsteroidal anti-inflammatory drugs (NSAIDs) and high-dose opioids. In this setting, local infiltration analgesia (LIA) with a vasoconstrictor offers an effective alternative. By blocking local nociceptive pathways, it mitigates surgical stress and stabilizes hemodynamics, decreasing the need for systemic drugs and protecting the functional reserve of the remaining kidney.

Objective: To describe the perioperative anesthetic strategy and evaluate the analgesic and nephroprotective impact of LIA in a solitary kidney patient undergoing robotic TKA without a mechanical tourniquet.

Methodology: A 72-year-old female, monorrenal secondary to a right radical nephrectomy (performed 18 years ago for stage III clear cell carcinoma), with comorbidities of type 2 diabetes mellitus and hypertension. Her preoperative creatinine was 1.16 mg/dL (102.5 μmol/L). The procedure was performed under light intravenous sedation with midazolam (1 mg) and fentanyl (5 μg), followed by single-dose spinal anesthesia (12.5 mg of bupivacaine plus 25 μg of fentanyl). An LIA targeting six periarticular anatomical components was administered, utilizing a total solution volume of 140 mL with 0.2% ropivacaine and 1:200,000 epinephrine (5 μg/mL). Pain progression was monitored using the numerical rating scale (NRS) at 0, 6, 12, 24, and 48 hours.

Results: The robotic surgery concluded without hemodynamic incidences or significant bleeding. Postoperative analgesic monitoring showed NRS scores of 0 at 0 hours, 4 at 6 and 12 hours, returning to 0 at 24 and 48 hours. No rescue analgesia with opioids or NSAIDs was required during follow-up. Effective ambulation was achieved at 24 hours. Renal function remained stable, documenting a persistent urine output greater than 0.5 mL/kg/h and a 24-hour serum creatinine of 1.29 mg/dL (114.0 μmol/L). This ruled out AKI according to KDIGO criteria, as it did not reach the dysfunction threshold, and showed no signs of fluid overload or elevated nitrogenous wastes.

Conclusions: LIA with ropivacaine and epinephrine, integrated into a spinal anesthesia regimen, proved to be a safe and highly effective analgesic tool in tourniquetless robotic TKA for patients with a solitary kidney. By suppressing moderate-to-severe pain and avoiding nephrotoxic agents, this technique favored perioperative renal stability and enabled successful ultra-early ambulation.