A prospective, randomized trial of liposomal bupivacaine compared to conventional bupivacaine on pain control and postoperative opioid use in adults receiving adductor canal blocks for total knee arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) is a commonly performed procedure to alleviate pain and improve functional limitations caused by end-stage joint damage. Effective management of postoperative pain following TKA is crucial to the prevention of complications and enhancement of recovery. Adductor canal blocks (ACB) with conventional bupivacaine (CB) provide adequate analgesia after TKA, but carry a risk of rebound pain following block resolution. Liposomal bupivacaine (LB) is an extended-release local anesthetic that can provide up to 72 h of pain relief. The objective of this study was to compare postoperative outcomes between ACBs using LB and CB after TKA. METHODS: This single institution, prospective, randomized, clinical trial enrolled patients scheduled for TKA. Participants were randomized to receive ACB with either LB or CB. Pain scores up to 72 h postoperatively were assessed as the primary outcome. Opioid consumption and length of stay were evaluated as secondary outcomes. RESULTS: A total of 80 patients were enrolled. Demographic and clinical characteristics were similar between the two groups. LB group showed significantly lower cumulative opioid use during the 72 h evaluated (P = 0.016). There were no differences in pain scores or length of stay between the groups. CONCLUSION: The study demonstrated that LB ACBs led to significantly lower opioid consumption in the days following TKA without affecting pain scores or length of stay. This finding has important implications for improving postoperative outcomes and reducing opioid use in TKA patients. Previous studies have reported inconsistent results regarding the benefits of LB, highlighting the need for further research. TRIAL REGISTRATION: This project was retrospectively registered with clinicaltrials.gov ( NCT05635916 ) on 2 December 2022.

Lobe transport analysis of the Kelvin-Stuart cat's eyes driven flow.

Mixing and transport in the driven Kelvin-Stuart cat's eyes dynamical system is studied using lobe transport theory and the topological approximation method (TAM). The application of the TAM also provides a global bifurcation analysis. Lobe areas are calculated using the Melnikov amplitude function, which has been derived for the Kelvin-Stuart system. Results indicate that regions, originally in the exterior above the vortex chain, can be transported to the exterior below the vortex chain (and vice versa) by passing through the interior, and that a region within the interior of a given vortex can be transported to the interior of a neighboring vortex, or the interior of a vortex several vortices distant from the given vortex. Cumulative transport is shown to decrease with increasing perturbation frequency for a fixed value of perturbation strength. Cumulative transport increases with increasing perturbation strength for a fixed value of the structure index L. Cumulative transport approaches a characteristic maximum value for each set of parameter values. Results demonstrate a linear dependence of the maximum cumulative transport upon a universal flux function of the form proposed by Rom-Kedar and Poje, suggesting a possible scaling in the transport dependent on the structure index L.