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A continuous adductor canal block for total knee arthroplasty reduces opioid consumption compared with that of placebo in the first 48 hours after surgery. Other outcomes including quadriceps strength, distance ambulated, and pain scores all show benefit from an adductor canal catheter after total knee arthroplasty but require further study before being interpreted as conclusive.

Manganese superoxide dismutase 2 (SOD2) is a critical component of the mitochondrial pathway for detoxification of O2 −, and targeted disruption of this locus leads to embryonic or neonatal lethality in mice. To follow the effects of SOD2 deficiency in cells over a longer time course, we created hematopoietic chimeras in which all blood cells are derived from fetal liver stem cells of Sod2 knockout, heterozygous, or wild-type littermates. Stem cells of each genotype efficiently rescued hematopoiesis and allowed long-term survival of lethally irradiated host animals. Peripheral blood analysis of leukocyte populations revealed no differences in reconstitution kinetics of T cells, B cells, or myeloid cells when comparing Sod2 +/+, Sod2 −/−, and Sod2 +/− fetal liver recipients. However, animals receiving Sod2 −/− cells were persistently anemic, with findings suggestive of a hemolytic process. Loss of SOD2 in erythroid progenitor cells results in enhanced protein oxidative damage, altered membrane deformation, and reduced survival of red cells. Treatment of anemic animals with Euk-8, a catalytic antioxidant with both SOD and catalase activities, significantly corrected this oxidative stress–induced condition. Such therapy may prove useful in treatment of human disorders such as sideroblastic anemia, which SOD2 deficiency most closely resembles.

Purpose The saphenous nerve block using a landmarkbased approach has shown promise in reducing postoperative pain in patients undergoing arthroscopic medial meniscectomy. We hypothesized that performing an ultrasound-guided adductor canal saphenous block as part of a multimodal analgesic regimen would result in improved analgesia after arthroscopic medial meniscectomy. Methods Fifty patients presenting for ambulatory arthroscopic medial meniscectomy under general anesthesia were prospectively randomized to receive an ultrasoundguided adductor canal block with 0.5% ropivacaine or a sham subcutaneous injection of sterile saline. Our primary outcome was resting pain scores (numerical rating scale; NRS) upon arrival to the postanesthesia care unit (PACU). Secondary outcomes included NRS at six hours, 12 hr, 18 hr, and 24 hr; postoperative nausea; and postoperative opioid consumption.Results There was a statistically significant difference in mean NRS pain scores upon arrival to the PACU (P = 0.03): block group NRS = 1.71 (95% confidence interval [CI] 0.73 to 2.68) vs sham group NRS = 3.25 (95% CI 2.27 to 4.23). Cumulative opioid consumption (represented in oral morphine equivalents) over 24 hr was 71.8 mg (95% CI 56.5 to 87.2) in the sham group vs 44.9 mg (95% CI 29.5 to 60.2) in the block group (P = 0.016). Conclusions An ultrasound-guided block at the adductor canal as part of a combined multimodal analgesic regimen significantly reduces resting pain scores in the PACU following arthroscopic medial meniscectomy. Furthermore, 24-hr postoperative opioid consumption and pain scores were also reduced. RésuméObjectif Le bloc du nerf saphène à l'aide d'une approche par repères anatomiques s'est avéré prometteur pour réduire la douleur postopératoire chez les patients subissant une méniscectomie médiale par arthroscopie. Nous avons émis l'hypothèse qu'en réalisant un bloc échoguidé du canal adducteur du nerf saphène dans le cadre d'un régime analgésique multimodal, l'analgésie serait plus efficace après une méniscectomie médiale par arthroscopie. Méthode Cinquante patients devant subir une méniscectomie médiale par arthroscopie en ambulatoire sous anesthésie générale ont été randomisés de façon prospective à recevoir un bloc échoguidé du canal adducteur avec de la ropivacaïne 0,5 % ou une injection sous-cutanée fictive de solution saline stérile. Notre critère d'évaluation principal était les scores de douleur au repos (échelle d'évaluation numérique; É É N) à l'arrivée en salle de réveil. Les critères d'évaluation secondaires comprenaient l'É É N à six heures, 12 h, 18 h et 24 h; les nausées Author contributions Neil A. Hanson and Francis V. Salinas were involved in the study design.