Traumatic arthritis and osteoarthritis may be the most common cause of lameness in equine athletes of all types.1 In the Thoroughbred racehorse industry worldwide, musculoskeletal injury accounts for the highest proportion of days lost from training2–5 and is the most common cause of athletic morbidity.3,4,6–8
Synovitis has been implicated in the initiation of osteoarthritis in racehorses.9–13 Intra-articular analgesics (mepivacaine, lidocaine, and bupivacaine14) and intra-articular therapeutic agents (corticosteroids, polysulfated glycosaminoglycans, and hyaluronic acid derivatives) remain important aids in the diagnosis of acute synovitis and treatment of affected horses and help in the prevention of additional degenerative articular changes.13,15
Current practice is to inject a local anesthetic into an affected joint and follow up with intra-articular administration of a corticosteroid between 1 and 7 days later because reactive synovitis (synovial flare) can be incited after injection of the local anesthetic,16 thus interfering with the absorption and efficacy of the corticosteroid. The prevalence of synovial flare responses in humans treated for arthritis is reportedly 2%.17 In clinical practice, the ability to administer 1 intra-articular injection of a combination of TAa and mepivacaineb would be useful for confirming the site of lameness and treating any synovitis or arthritis that existed there. This single-injection technique would eliminate the need for additional synovial injections, thus reducing potential injury to veterinarians and the risk of synovial sepsis for horses.18,19
Triamcinolone acetonide has recently become popular as an intra-articular medication for high-motion joints because of its purported chondroprotective and anti-inflammatory properties.20–22 In studies of the effects of TA in horses, the analgesic has been injected into the same joint multiple times23 or into multiple joints at 1 time point.24 To our knowledge, the effects of 1 TA injection or TA combined simultaneously with other medications injected into 1 joint of a horse have not been evaluated. Mepivacaine hydrochloride is the local anesthetic of choice for diagnostic intra-articular analgesia because it causes less irritation of the articular environment than lidocaine.25
The purpose of the study reported here was to determine the efficacy, safety, and duration of action of 1 injection of TA or mepivacaine alone, or TA and mepivacaine in combination, on the degree of lameness, joint kinetics, and indicators of synovial inflammation by use of an established protocol for induction of lameness and synovitis in equine MCP joints with Escherichia coli LPS.26,27 In addition, we sought to determine whether local and systemic drug concentrations would be correlated with clinical efficacy scores.
Vertical force peak
Vetalog, Fort Dodge Animal Health, Fort Dodge, Iowa.
Carbocaine-V, Pfizer Inc, New York, NY.
Difco Laboratories, Detroit, Mich.
Sigma Chemical Co, St Louis, Mo.
Truesdail Laboratory Inc, Tustin, Calif.
Model 9281C, Kistler Instrument Corp, Amherst, NY.
Vacutainer, Tyco Healthcare, Mansfield, Mass.
10482 ABBE Mark II Refractometer, Reichert Scientific Instruments, Buffalo, NY.
VWR-International, West Chester, Pa.
Neogen test protocol, Neogen Corp, Lexington, Ky.
SAS, version 9.1, SAS Institute Inc, Cary, NC.
Caron JP. Osteoarthritis. In: Ross MW, Dyson SJ, eds. Diagnosis and management of lameness in the horse. Philadelphia: WB Saunders Co, 2003;572–591.
Verheyen KL, Wood JL. Descriptive epidemiology of fractures occurring in British Thoroughbred racehorses in training. Equine Vet J 2004;36:167–173.
Bailey CJ, Reid SW, Hodgson DR, et al. Impact of injuries and disease on a cohort of two and three year old thoroughbreds in training. Vet Rec 1999;145:487–493.
Olivier A, Nurton JP, Guthrie AJ. An epizoological study of wastage in thoroughbred racehorses in Gauteng, South Africa. J S Afr Vet Assoc 1997;68:125–129.
Boden LA, Anderson GA, Charles JA, et al. Risk of fatality and causes of death of Thoroughbred horses associated with racing in Victoria, Australia: 1989–2004. Equine Vet J 2006;38:312–318.
Perkins NR, Reid SWJ, Morris RS. Profiling the New Zealand thoroughbred racing industry, 2. Conditions interfering with training and racing. N Z Vet J 2004;53:69–76.
Peloso JG, Mundy GD, Cohen ND. Prevalence of and factors associated with musculoskeletal racing injuries of Thoroughbreds. J Am Vet Med Assoc 1994;204:620–626.
McIlwraith CW. General pathobiology of the joint and response to joint injury. In: McIlwraith CW, Trotter GW, eds. Joint disease in the horse. Philadelphia: WB Saunders Co, 1996;40–70.
Palmer JL, Bertone AL. Joint structure, biochemistry and biochemical disequilibrium in synovitis and equine joint disease. Equine Vet J 1994;26:263–277.
Spiers S, May SA, Bennett D, et al. Cellular sources of proteolytic enzymes in equine joints. Equine Vet J 1994;26:43–47.
Bassage LH, Ross MW. Diagnostic analgesia. In: Ross MW, Dyson SJ, eds. Diagnosis and management of lameness in the horse. Philadelphia: WB Saunders Co, 2003;93–124.
Caron JP. Intra-articular injections for joint disease in horses. Vet Clin North Am Large Anim Pract 2005;21:559–573.
Bertone AL. Infectious arthritis. In: Ross MW, Dyson SJ, eds. Diagnosis and management of lameness in the horse. Philadelphia: WB Saunders Co, 2003;598–605.
Lapointe JM, Laverty S, Lavoie JP. Septic arthritis in 15 standardbred racehorses after intra-articular injection. Equine Vet J 1992;24:430–434.
Schneider RK, Bramlage LR, Moore RM, et al. A retrospective study of 192 horses affected with septic arthritis/tenosynovitis. Equine Vet J 1992;24:436–440.
Frisbie DD, Kawcak CE, Trotter GW, et al. Effects of triamcinolone acetonide on an in-vivo equine osteochondral fragment exercise model. Equine Vet J 1997;29:349–359.
Kawcak CE, Norrdin RW, Frisbie DD, et al. Effects of osteochondral fragmentation and intra-articular triamcinolone acetonide treatment on subchondral bone in the equine carpus. Equine Vet J 1998;30:66–71.
Pelletier JP, Martel-Pelletier J. Protective effects of corticosteroids on cartilage lesions and osteophyte formation in the Pond-Nuki dog model of osteoarthritis. Arthritis Rheum 1989;32:181–193.
Celeste C, Ionescu M, Poole AR, et al. Repeated intra-articular injections of triamcinolone acetonide alter cartilage matrix metabolism measured by biomarkers in synovial fluid. J Orthop Res 2005;23:602–610.
Chen CL, Sailor JA, Collier J, et al. Synovial and serum levels of triamcinolone following intra-articular administration of triamcinolone acetonide in the horse. J Vet Pharmacol Ther 1992;15:240–246.
Specht TE, Nixon AJ, Meyer DJ. Equine synovia after intra-articular injection of lidocaine or mepivacaine. Vet Surg 1988;17:42–49.
Ishihara A, Bertone AL, Rajala-Schultz PJ. Association between lameness grade and kinetic gait parameters in horses with experimentally induced forelimb lameness. Am J Vet Res 2005;66:1805–1815.
Palmer JL, Bertone AL. Experimentally-induced synovitis as a model for acute synovitis in the horse. Equine Vet J 1994;26:492–495.
Merkens HW, Schamhardt HC, Hartman W, et al. Ground reaction force patterns of Dutch Warmblood horses at normal walk. Equine Vet J 1986;18:207–214.
Merkens HW, Schamhardt HC. Evaluation of equine locomotion during different degrees of experimentally induced lameness. I: lameness model and quantification of ground reaction force patterns of the limbs. Equine Vet J Suppl 1988;6:99–106.
McLaughlin RM, Gaughan EM, Roush JK, et al. Effects of subject velocity on ground reaction force measurements and stance times in clinically normal horses at the walk and trot. Am J Vet Res 1996;57:7–11.
Riemersma DJ, Bogert AJ, Jansen MO, et al. Influence of shoeing on ground reaction forces and tendon strains in the forelimbs of ponies. Equine Vet J 1996;28:126–132.
Hodson E, Clayton HM, Lanovaz JL. The forelimb in walking horses 1: kinematics and ground reaction forces. Equine Vet J 2000;32:287–294.
Khumsap S, Clayton HM, Lanovaz JL, et al. Effect of walking velocity on forelimb kinematics and kinematics. Equine Vet J Suppl 2002;34:325–329.
Misheff MM, Stover SM. A comparison of two techniques for arthrocentesis of the equine metacarpophalangeal joint. Equine Vet J 1991;23:273–276.
American Association of Equine Practitioners. Lameness scale. Definition and classification of lameness. In: Guide for veterinary service and judging of equestrian events. 4th ed. Lexington, Ky: American Association of Equine Practitioners, 1991;19.
Simmons EJ, Bertone AL, Weisbrode SE. Instability-induced osteoarthritis in the metacarpophalangeal joint of horses. Am J Vet Res 1999;60:7–13.
Stashak TS. Examination of lameness. In: Stashak TS, ed. Adam's lameness in horses. 5th ed. Philadelphia: Lippincott Williams & Wilkins, 2002;113–183.
Strand E, Martin GS, Crawford MP, et al. Intra-articular pressure, elastance and range of motion in healthy and injured racehorse metacarpophalangeal joints. Equine Vet J 1998;30:520–527.
Cornelissen BPM, Rijkenhuizen ABM, van der Hoogen BM, et al. Experimental model of synovitis/capsulitis in the equine metacarpophalangeal joint. Am J Vet Res 1998;59:978–985.
Hardy J, Bertone AL, Muir WM. Local hemodynamics, permeability, and oxygen metabolism during acute inflammation of innervated and denervated isolated equine joints. Am J Vet Res 1998;59:1307–1316.
Bertone AL, Hardy J, Simmons EJ, et al. Vascular and trans-synovial forces of the isolated stationary equine joint. Am J Vet Res 1998;59:495–503.
Todhunter PG, Kincaid SA, Todhunter RJ, et al. Immunohistochemical analysis of an equine model of synovitis-induced arthritis. Am J Vet Res 1996;57:1080–1093.
Hawkins DL, Mackay RJ, Gum GG, et al. Effect of intra-articularly administered endotoxin on clinical signs of disease and synovial fluid tumor necrosis factor, interleukin 6, and prostaglandin E2 values in horses. Am J Vet Res 1993;54:379–386.
Welch RD, Watkins JP, DeBowes RM, et al. Effects of intra-articular administration of dimethylsulfoxide on chemically induced synovitis in immature horses. Am J Vet Res 1991;52:934–939.
Back W, Barneveld A, Weeren PR, et al. Kinematic gait analysis in equine carpal lameness. Acta Anat (Basel) 1993;146:86–89.
Axelrod L. Glucocorticoids. In: Harris ED, Kelley WN, Ruddy S, et al, eds. Textbook of rheumatology. 4th ed. Philadelphia: WB Saunders Co, 1993;779–796.
Wright JM, Knight C, Hunneyball I. The effect of side-chain structure on the biochemical and therapeutic properties of intra-articular dexamethasone 21-esters. Clin Exp Rheumatol 1986;4:331–339.
Szefler SJ. General pharmacology of glucocorticoids. In: Schleimer RP, Claman HN, Oronsky AL, eds. Anti-inflammatory steroid action: basic and clinical aspects. San Diego: Academic Press Inc, 1989;353–376.
White KK, Hodgson DR, Hancock D, et al. Changes in equine carpal joint synovial fluid in response to the injection of two local anesthetic agents. Cornell Vet 1989;79:25–38.
Judy CE, Galuppo LD. Evaluation of iatrogenic hemarthrosis of the metacarpophalangeal joint as a method of induction of temporary reversible lameness in horses. Am J Vet Res 2005;66:1084–1089.
Harkins JD, Stanley S, Mundy GD, et al. A review of the pharmacology, pharmacokinetics and regulatory control in the US of local anesthetics in the horse. J Vet Pharmacol Ther 1995;18:397–406.
European Horserace Scientific Liaison Committee. Information for veterinary surgeons on detection periods of named drugs. Newmarket, England: R&W Publications Ltd, 1997.
Australian Equine Veterinary Association. Detection of substances in racing horses. Artarmon, Australia: Australian Equine Veterinary Association, 1992;8–49.
Williams GE, Silverman BW, Wilson AM, et al. Disease specific changes in equine ground reaction force data documented by use of principal component analysis. Am J Vet Res 1999;60:549–555.
Clayton HM, Schamhardt HC, Willemen MA, et al. Kinematics and ground reaction forces in horses with superficial digital flexor tendonitis. Am J Vet Res 2000;61:191–196.
Trotter GW, McIlwraith CW. Clinical features and diagnosis of equine joint disease. In: McIlwraith CW, Trotter GW, eds. Joint disease in the horse. Philadelphia: WB Saunders Co, 1996;40–70.
Dyson S. Problems associated with the interpretation of the results of regional and intra-articular anesthesia in the horse. Vet Rec 1986;118:419–422.
Strand E, Martin GS, Crawford MP, et al. Intra-articular pressure, elastance, and range of motion in flexion of the equine metacarpophalangeal joint. Am J Vet Res 1995;56:1362–1371.
Levick JR. Contributions of the lymphatic and microvascular systems to fluid absorption from the synovial cavity of the rabbit knee. J Physiol 1980;306:445–461.
Mcdonald JN, Levick JR. Pressure induced deformation of the interstitial route across synovium and its relation to hydraulic conductance. J Rheumatol 1990;17:341–348.
Levick JR. Synovial fluid dynamics: the regulation of volume and pressure. In: Holborrow EJ, Maroudas A, eds. Studies in joint diseases. London: Pitman, 1983;140–153.
Smith G, Bertone AL, Kaeding C, et al. Anti-inflammatory effects of topically applied dimethyl sulfoxide gel on endotoxin-induced synovitis in horses. Am J Vet Res 1998;59:1149–1152.