Ultrasound-guided adductor canal block combined with lateral femoral cutaneous nerve block for post-operative analgesia following total knee arthroplasty: a prospective, double-blind, randomized controlled study

Purpose

The purpose of this study was to investigate whether adductor canal block (ACB) combined with lateral femoral cutaneous nerve block (LFCNB) could improve the efficacy of post-operative analgesia in a comparison with a standard peri-articular infiltration analgesia (PIA) after a total knee arthroplasty (TKA).

Methods

One hundred and sixty patients of scheduled unilateral primary TKA were randomly allocated into two groups for post-operative analgesia. Eighty cases were treated with ACB combined with LFCNB and the other eighty treated with PIA. The primary outcomes were pain visual analogue scale (VAS) and rescue pain killer consumption, and the secondary outcomes were knee active range of motion (ROM), quadriceps strength, patients’ ambulation ability, Knee Society Score (KSS), length of hospital stay, and adverse events.

Results

We found that ACB combined with LFCNB was better on decreasing the post-operative pain score within 12 hours at rest and 8 h with activity (p < 0.05) and provided longer duration of analgesia (19.91 ± 5.09 VS 12.06 ± 3.67 h, p < 0.01) and less rescue morphine consumption (13.63 ± 9.84 vs 18.00 ± 11.52 mg, p = 0.011) than the PIA. There was no significant difference between the two groups (p > 0.05) in terms of knee ROM, quadriceps strength, daily mobilization distance, KSS, and complication occurrence.

Conclusions

ACB combined with LFCNB provides a significantly better pain control, less opioid consumption, and longer duration of analgesia than peri-articular infiltration while preserving muscle function without affecting knee functional recovery nor the length of stay or side effects occurrence.