Objective:There is growing concern that intra-articular injection of local anesthetic and/or corticosteroids may cause significant morbidity, including potential toxicity to chondrocytes and synoviocytes, after even a single exposure. We demonstrate that full thickness canine chondral and synovial samples exposed to various local anesthetics and corticosteroids exhibit decreased loss of cell viability compared with prior in vitro studies using monolayer culture, due to the protective effects of intact extracellular matrix and cell heterogeneity.Methods:Full-thickness cartilage and synovial explants were obtained from canine cadavers and exposed in culture media to the following for 24 hours: 1% lidocaine, 0.5% lidocaine, 0.25% bupivacaine, 0.125% bupvacaine, 0.0625% bupivacaine, betamethasone acetate, methylprednisolone acetate, triamcinolone acetonide, or culture media only (control). Cell viability was determined on days 1 and 7 of culture using a microscopic live-dead and alamar blue metabolic assays.Results:Complete loss of chondrocyte and synoviocyte viability was noted in the 1% and 0.5% lidocaine group, 0.25% and 0.125% bupivacaine group, betamethasone group, and methylprednisolone groups after 1 and 7 days of culture. Treatment with 0.0625% bupivacaine and triamcinolone demonstrated no decrease in cell viability or metabolism when compared to negative control.Conclusions:In this canine explant model, 1% and 0.5% lidocaine, 0.25% and 0.125% bupivacaine, betamethasone acetate, and methylpresdnisolone acetate were severely chondrotoxic and synoviotoxic after a single exposure, despite intact extracellular matrix. In contrast, chondrocytes and synoviocytes exposed to 0.0625% bupivacaine and triamcinolone remained viable after treatment. Further in vivo study is needed before definitive recommendations can be made.

Objective:Intra-articular injection of local anesthetic and/or corticosteroid is an adjunct treatment for arthritic and inflammatory orthopedic conditions. Despite potential benefits, there is growing concern that these medications may cause significant morbidity, including potential toxicity to intra-articular chondrocytes and synoviocytes.Design:Twenty dogs underwent intra-articular injection of the shoulder joint using ultrasound guidance, with the following injectates (n = 5 each): negative control (saline), methylprednisolone/1.0% lidocaine, triamcinolone/1.0% lidocaine, and triamcinolone/0.0625% bupivacaine. The dogs were euthanized 24 hours postinjection for reasons unrelated to this study. Synovium/cartilage explants were harvested under sterile conditions and assessed immediately or cultured for 7 days. Synoviocyte and chondrocyte viability was determined on day 1 and day 7 using Calcien AM and Sytox Blue live/dead fluorescent stains, and cell metabolism determined on day 2 using the alamar blue additive test. Results were compared statistically.Results:On day 1 synovium exposed to 1%L/M demonstrated a significant decrease in cell metabolism (P = 0.0107) and subjective synoviocyte viability scores (P = 0.013) compared with the negative control. Cartilage exposed to 1%L/M demonstrated decreased chondrocyte viability and cell metabolism versus all other groups, although not significantly. After 7 days of culture, cartilage viable cell density in the 1%L/M group was significantly (P ≤ 0.001) lower than the negative control. Subjective synoviocyte viability scores was significantly lower in the 1%L/M (P = 0.013), 1%L/T (P ≤ 0.001), and 0.0625%B/T groups (P = 0.006) compared with the negative control.Conclusions:This study suggests potential negative effects of combination local anesthetic/corticosteroid on intra-articular cell viability and cell metabolism. Further study is needed before determining definitive clinical recommendations.

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

There appears to be only a weak correlation between amount of pain medication prescribed and patients' reported subjective pain intensity within this limited patient population. The Medication Quantification Scale is a viable tool for the analysis of pharmaceutical treatment of CRPS patients and would be useful in further prospective studies of pain medication prescription practices in the CRPS population worldwide.

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