Evidence Basis for Regional Anesthesia in Ambulatory Anterior Cruciate Ligament Reconstruction: Part I—Femoral Nerve Block
Bibliographic record
Abstract
The optimal management of pain after ambulatory anterior cruciate ligament reconstruction (ACLR) is unclear. Femoral nerve block (FNB) is purported to enhance postoperative analgesia, but its effectiveness in the setting of modern multimodal analgesia is unclear. This systematic review examines the effect of adding FNB to multimodal analgesia on analgesic outcomes after ACLR, whether or not the analgesic regimen used included local instillation analgesia (LIA). We retrieved randomized controlled trials evaluating the effects of adding FNB to multimodal analgesia on analgesic outcomes after ACLR, compared to multimodal analgesia alone (control). We designated postoperative opioid consumption at 24 hours as our primary outcome. Secondary outcomes included postoperative opioid consumption at 24-48 hours, rest, and dynamic pain severity between 0 and 48 hours, time to analgesic request, postanesthesia care unit and hospital stay durations, patient satisfaction, postoperative nausea and vomiting, functional outcomes, and long-term (>1 month) quadriceps strength. Eight randomized controlled trials (716 patients) were identified. Five trials compared FNB administration to control, and another 3 compared the combination of FNB and LIA to LIA alone. Compared to control, adding FNB resulted in modest reductions in 24-hour opioid consumption in 2 of 3 trials, and improvements in rest pain at 1 hour in 1 trial and up to 24 hours in another. In contrast, the combination of FNB and LIA, compared to LIA alone, did not reduce opioid consumption in any of the trials, but it did improve pain scores at 20 minutes only in 1 trial. The effect of FNB on long-term quadriceps strength or function after ACLR was not evaluated in the reviewed trials. Contemporary evidence suggests that the benefits of adding FNB to multimodal analgesia for ACLR are modest and conflicting, but there is no incremental analgesic benefit if the multimodal analgesic regimen included LIA. Our findings do not support the routine use of FNB for analgesia in patients having ACLR.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.010 | 0.047 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.006 | 0.010 |
| Bibliometrics | 0.006 | 0.005 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.004 | 0.002 |
| Open science | 0.003 | 0.002 |
| Research integrity | 0.003 | 0.003 |
| Insufficient payload (model declined to judge) | 0.010 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".