This prospective, triple-blinded, sham-controlled randomized trial evaluates the additive effect of Supra-Sartorial Subcutaneous Infiltration (SSSI) combined with intermittent adductor canal block (iACB) and posterior capsule local infiltration analgesia (PC-LIA) for pain management in total knee arthroplasty (TKA). SSSI, a simpler alternative to targeted anterior femoral cutaneous nerve (AFCN) block, is tested in 90 adults (45-90 years) randomized into two arms: sham SSSI + active iACB + PC-LIA versus all active interventions. Primary outcome is pain scores on postoperative day 0; secondary outcomes include daily pain trajectory, opioid use, functional recovery, and complications over days 0-3.
This prospective, two-armed, triple-blinded, sham-controlled randomized controlled trial investigates the additive effect of Supra-Sartorial Subcutaneous Infiltration (SSSI) to intermittent adductor canal block (iACB) and posterior capsule local infiltration analgesia (PC-LIA) in multimodal pain management for total knee arthroplasty (TKA). SSSI is a peripheral nerve block technique the investigators devised as a simpler alternative to targeted anterior femoral cutaneous nerve (AFCN) block, which is technically more demanding and time-consuming. Based on the investigators' preliminary study (in publication) where SSSI combined with PC-LIA provided clinically meaningful analgesia in \~58% of patients, and drawing from previous studies on AFCN blocks, the trial compares: Arm 1 (all active SSSI + active iACB + active PC-LIA) versus Arm 2 (sham SSSI + active iACB + active PC-LIA). Adults (45-90 years) undergoing unilateral primary TKA (n=90, 45/arm) will be randomized 1:1, stratified by age, preoperative pain levels (in Numerical Rating Scale) and functional status (WOMAC Index or Knee Society Score). Interventions use 0.3% ropivacaine or saline shams, with SSSI and ACB catheterization performed in the post-anesthesia care unit by anesthesiologists and PC-LIA performed intraoperatively by surgeons. Primary outcome: Numerical Rating Scale pain scores at rest and during continuous passive motion at 9:00 PM on postoperative day (POD) 0, focusing on anteromedial knee pain. Secondary outcomes include daily pain scores, rescue ACB doses, additional opioid use, functional recovery (quadriceps strength, timed up and go \[TUG\] test), and complications over POD 0-3. With \~96% power for a 2-point NRS difference, this trial evaluates SSSI's role in enhancing motor-sparing analgesia.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
90
20 mL ropivacaine or saline infiltrated lateral-to-medial subcutaneously above sartorius at femoral triangle apex using inject-as-you-advance technique, avoiding hyperechoic nerves.
An adductor canal catheter is inserted proximal-to-distally over a distance of 6-10 cm at femoral triangle apex, with an initial bolus of 10 mL of 0.3% ropivacaine administered in PACU. The following doses start at 9:00 PM on the day of surgery and are repeated every 12 hours,
PC-LIA consists of two 10 mL injections of 0.3% ropivacaine delivered intraoperatively to the posteromedial and posterolateral aspects of the posterior capsule before cementation. The target injection plane is the potential space between the posterior capsule and the popliteal artery.
Pain: NRS at rest/movement on postoperative day 0 (with a focus on the anteromedial aspect of knee)
NRS pain scores (0-10) at rest and during continuous passive motion will be taken on postoperative day 0 at 9:00 PM. Higher NRS pain scores indicate worse pain levels.
Time frame: at 9:00 PM on postoperative day 0
Pain: NRS at rest/movement (anteromedial vs posterior aspect of knee) from postoperative day 1-3
NRS pain scores (0-10) will be taken at rest/during TUG test on postoperative day 1 (9:00 AM, 9 :00 PM), POD 2 (9:00 AM, 9 :00 PM), and POD 3 (9:00 AM). Higher NRS pain scores indicate worse pain levels.
Time frame: From postoperative day 1 at 9:00 AM to postoperative day 3 at 9:00 AM.
Rescue ACB doses (0.3% ropivacaine, mg)
Rescue ACB will be administered via catheter as needed outside of the scheduled doses (from postoperative day 0 at 9:00PM to postoperative day 3 at 9:00 AM, q12 hours).
Time frame: From the time entering post-anesthesia care unit to postoperative day 3 at 9:00 AM
Additional morphine doses (mg)
Intravenous morphine as bolus or patient-controlled analgesia may be administered as needed if regional anesthesia fails to providing adequate analgesia (NRS pain \<4).
Time frame: From the time entering post-anesthesia care unit to postoperative day 3 at 9:00 AM
Functional: Quadriceps strength (dynamometer), TUG test
Quadriceps strength will be tested using a dynamometer together with TUG test from postoperative day 1 at 9:00 AM to postoperative day 3 at 9:00 AM, q24 hours
Time frame: From postoperative day 1 at 9:00 AM to postoperative day 3 at 9:00 AM.
Complications
Complications such as falls, hematoma/oozing/infection at the catheterization site, catheter dislodgement, etc., will be recorded from postoperative day 0 to postoperative day 3.
Time frame: From postoperative day 0 at 9:00 PM to postoperative day 3 at 9:00 AM.
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