Continuous Adductor Canal Block (CACB) vs. Combined Spinal Epidural (CSE) in Total Knee Arthroplasty

Purpose: Compare continuous adductor canal block (CACB) to Combined Spinal Epidural (CSE) for total knee arthroplasty in terms of mobility, post-operative pain, and analgesic use.

Hypothesis: CACB will provide better mobility than CSE post operatively.

Background/Scientific Review:

Total knee arthroplasty (TKA) is associated with varying degrees of pain post operatively ranging from mild to severe despite the use of comprehensive multimodal analgesic regimens1. Optimizing pain relief is vital for functional recovery after total knee arthroplasty2. Peripheral nerve blocks have been commonly used to improve pain relief and reduce opioid requirements. The addition of nerve blocks involving the femoral nerve have been shown to provide superior pain control3 and shortened hospital stay compared to epidural or intravenous patient controlled analgesia alone1. However, femoral nerve blocks can result in quadriceps weakness leading to functional impairment and an increased risk of falling post operatively4. Unlike Femoral Nerve Blocks (FNB), adductor canal blocks (ACB) are predominantly sensory blocks which preserve quadriceps muscle strength and ambulation ability better than FNBs, while providing equivalent pain relief5-9.

Recent randomized studies have also shown ACB to be superior to placebo in the setting of spinal and general intraoperative anesthesia in terms of ambulation, pain control, and opioid consumption10-12. In a recent retrospective cohort study, the addition of ACB to local infiltration analgesia (LIA) was associated with further improvement in early ambulation benchmarks and a higher rate of home discharge compared with only LIA9. While CACB and CSE are used as part of routine care at Rush University Medical Center and around the country, there have been no studies directly comparing CACB to CSE.