Effects of intra-articular administration of lidocaine, mepivacaine, and the preservative methyl parahydroxybenzoate on synovial fluid biomarkers of horses

Abstract

OBJECTIVE To compare the extent of inflammation and catabolic collagen response in the middle carpal joints (MCJs) of healthy horses following intra-articular injection of 2% lidocaine, 2% mepivacaine, lactated Ringer solution (LRS), or 0.1% methyl parahydroxybenzoate. ANIMALS 17 adult horses. PROCEDURES In the first of 2 experiments, the left middle carpal joint (MCJ) of each of 12 horses was injected with 10 mL of 2% lidocaine (n = 3), 2% mepivacaine (3), or LRS (control; 6). After a 4-week washout period, the right MCJ of the horses that received lidocaine or mepivacaine was injected with 10 mL of LRS, and the right MCJ of horses that received LRS was injected with 10 mL of 2% lidocaine (n = 3) or 2% mepivacaine (3). In experiment 2, the left MCJ of each of 5 horses was injected with 10 mL of 0.1% methyl parahydroxybenzoate. After a 48-hour washout period, the right MCJ of each horse was injected with 10 mL of LRS. Synovial fluid (SF) samples were aseptically collected before and at predetermined times after each injection. Synovial fluid WBC count, neutrophil percentage, and total protein, neutrophil myeloperoxidase, neutrophil elastase, and Coll2-1 concentrations were compared among treatments. RESULTS Both lidocaine and mepivacaine induced SF changes indicative of inflammation and a catabolic collagen response, but the magnitude of those changes was more pronounced for lidocaine. Methyl parahydroxybenzoate did not cause any SF changes indicative of inflammation. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that mepivacaine was safer than lidocaine for intra-articular injection in horses.

Influence of clinical and experimental intra‐articular inflammation on neutrophil gelatinase‐associated lipocalin concentrations in horses

“…This finding was further corroborated by SF NGAL levels after experimental injection of the two local analgesics. Intra‐articular injections of lidocaine and mepivacaine cause moderate and mild inflammation, respectively, 29 and this was matched by higher SF NGAL concentrations in the lidocaine group compared with the mepivacaine group. These findings provide evidence that NGAL is a potential new biomarker for assessing severity of/monitoring inflammation similar to what has been demonstrated for SAA 4 …”

“…Serum and SF samples were available from 12 horses (all mares, 5‐17 years old, 495‐611 kg). Six horses were injected with 200 mg lidocaine (Xylocaine, 20 mg/mL; AstraZeneca, Copenhagen, Denmark), and six horses were injected with 200 mg mepivacaine (carbocaine, 20 mg/mL; AstraZeneca) in one middle carpal joint as described in Adler et al 29 Intra‐articular lidocaine injection caused moderate synovial inflammation with peak SF WBC (at 12 hours) of 15.3 ± 4.6 × 10 9 /L; intra‐articular mepivacaine injection resulted in mild synovial inflammation with peak SF WBC (at 12 hours) of 1.7 ± 2.6 × 10 9 /L as described in detail in Adler et al 29 …”

“…Serum and SF samples were available from 12 horses (all mares, 5-17 years old, 495-611 kg). Six horses were injected with 200 mg lidocaine (Xylocaine, 20 mg/mL; AstraZeneca, Copenhagen, Denmark), and six horses were injected with 200 mg mepivacaine (carbocaine, 20 mg/mL; AstraZeneca) in one middle carpal joint as described in Adler et al 29 Intra-articular lidocaine injection caused moderate synovial inflammation with peak SF WBC (at 12 hours) of 15.3 ± 4.6 × 10 9 /L; intra-articular mepivacaine injection resulted in mild synovial inflammation with peak SF WBC (at 12 hours) of 1.7 ± 2.6 × 10 9 /L as described in detail in Adler et al 29 Blood and SF were collected before (0 hours) and after (6,12,24,48, and 168 hours) injection of the local analgesics and directly transferred to tubes (BD Vacutainer; Becton Dickinson A/S) containing no additive (for preparation of serum) and ethylenediaminetetraacetic acid (for assessment of WBC in whole blood and SF and for stabilizing SF for later NGAL measurements). Serum tubes and SF samples were centrifuged at 2500 g for 10 minutes at 4 C; all other sample handling and laboratory procedures for determining WBC in whole blood and SF were performed as previously described.…”

“…For this study, samples were available from two previous studies 28,29 and from horses admitted to the Large Animal Teaching Hospital at University of Copenhagen. Blood was drawn from an indwelling jugular venous catheter (in experimental studies) or by puncture of the jugular vein (in clinical cases).…”

Haematogenous septic arthritis, physitis and osteomyelitis in foals: A tutorial review on pathogenesis, diagnosis, treatment and prognosis. Part 1

“…A joint flare refers to an acute synovial inflammatory reaction, clinically mimicking septic processes with synovial distension and lameness. They may occur due to drug-related toxicities, immune-mediated processes, congenital malformations or atypical early osteochondrosis manifestations as listed below (Adler et al 2020).…”