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OBJECTIVE To examine changes occurring in normal pelvic suspensory ligaments (SLs) of horses after denervating these ligaments and to investigate the effect chronic inflammation might have on these changes. ANIMALS 10 horses. PROCEDURES The SL of 1 randomly selected pelvic limb of each of 5 horses was injected with collagenase to induce desmitis, and 42 days later, the proximal aspect of both pelvic SLs were denervated. The SLs were harvested 120 days after being denervated, and the morphological and histological characteristics of each collagenase-injected, denervated SL were compared with those of the contralateral, non-injected, denervated SL. All denervated SLs were compared with non-denervated pelvic SLs harvested from 5 horses similar in weight and age. RESULTS The mean width and the cross-sectional area of the musculature of all denervated SLs were significantly less than that of the non-denervated ligaments. The mean thickness of collagenase-injected denervated ligaments, but not that of the non-injected denervated ligaments, was significantly less than that of the non-denervated ligaments. Histological abnormalities typical of neurogenic muscular atrophy were observed in all denervated ligaments. CLINICAL RELEVANCE Loss of motor neuronal input to the proximal aspect of the SL of the pelvic limb of horses causes neurogenic atrophy of the musculature in that portion of the ligament. Denervating a SL of a pelvic limb may weaken the ligament, increasing its risk of injury. Chronic inflammation of the SL before neurectomy may exacerbate atrophy of the musculature after neurectomy.

OBJECTIVE To compare the speed of onset and analgesic effect of mepivacaine deposited within or immediately outside the neurovascular bundle at the base of the proximal sesamoid bones in horses. ANIMALS 6 horses with naturally occurring forefoot-related lameness. PROCEDURES In a crossover study design, horses were randomly assigned to receive 1 of 2 treatments first, with the second treatment administered 3 to 7 days later. Trotting gait was analyzed with an inertial sensor–based motion analysis system immediately before treatment to determine degree of lameness. Afterward, ultrasound guidance was used to inject 2% mepivacaine hydrochloride around the palmar digital nerves of the affected forelimb at the level of the base of the proximal sesamoid bones either within the subcircumneural space or outside the circumneural sheath. After injection, gait was reevaluated at 5-minute intervals for 45 minutes. RESULTS Mepivacaine deposition outside the circumneural sheath did not resolve lameness in any horse; for 3 horses, the mean time to 70% reduction of initial vertical head movement was 13.3 minutes, and the remaining 3 horses had no such reduction at any point. Mepivacaine deposition within the subcircumneural space resulted in a mean time to 70% reduction of initial vertical head movement of 6.7 minutes and mean time to resolution of lameness of 21.7 minutes. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that when peripheral nerves of horses lie within a sheath, local anesthetic solution should be deposited within the sheath for an effective nerve block. If local anesthetic solution is deposited outside the sheath, the nerve block may yield erroneous results.

OBJECTIVE To assess onset of analgesia for 3% chloroprocaine hydrochloride and 2% mepivacaine hydrochloride when used for median and ulnar nerve blocks in lame horses. ANIMALS 6 naturally lame horses. PROCEDURES A crossover experiment was conducted. Horses were assigned to 1 of 2 treatment groups (3% chloroprocaine or 2% mepivacaine first). Median and ulnar nerve blocks were performed in the lame limb with the assigned treatment. Lameness was objectively evaluated before treatment administration and at various points for 120 minutes after treatment with a wireless inertial sensor-based motion analysis system. Following a 7-day washout period, horses then received the other treatment and lameness evaluations were repeated. RESULTS Median and ulnar nerve blocks performed with 3% chloroprocaine resulted in more consistent, rapid, and profound amelioration of lameness than did blocks performed with 2% mepivacaine. Lameness decreased more between 20 and 40 minutes after injection when 3% chloroprocaine was used than when 2% mepivacaine was used. Complete resolution of lameness was detected a mean of 9 minutes after injection when median and ulnar nerve blocks were performed with 3% chloroprocaine and a mean of 28 minutes after injection when performed with 2% mepivacaine. CONCLUSIONS AND CLINICAL RELEVANCE 3% chloroprocaine had a more rapid onset and provided better analgesia for median and ulnar nerve blocks in horses with naturally occurring lameness, compared with 2% mepivacaine. These favorable properties suggest that 3% chloroprocaine would be useful for performance of median and ulnar regional nerve blocks during complicated lameness evaluations.

OBJECTIVE To compare the efficacy and duration of action for perineural analgesia with liposomal bupivacaine (LB) versus bupivacaine hydrochloride (BHCl) in a sole-pressure induced model of forelimb lameness in horses. ANIMALS 6 healthy adult research horses. PROCEDURES In 1 randomly assigned forelimb, grade 3/5 lameness was induced by use of a sole-pressure lameness model. Objective lameness (vector sum [VS]) was determined with an inertial sensor system at 0, 1, 6, and 24 hours after lameness induction to evaluate the model. Mechanical nociceptive thresholds (MNTs) and objective lameness (VS and force platform kinetics) were recorded prior to and at 1, 6, 24, 48, and 72 hours after perineural anesthesia of the palmar nerves at the level of the proximal sesamoid bones with LB or BHCl in random order, with a 1-week washout period between crossover treatments. Data analysis was performed with mixed-model ANOVA. RESULTS When evaluating the lameness model, there was a decrease in lameness at 24 hours in at least 1 limb of each horse (7/12 limbs); thus, screw length was increased by 1 to 2 mm at each 24-hour interval to maintain lameness. Compared with results at baseline, horses treated with BHCl had significant improvements in median MNT and VS identified at only 1 hour after injection, whereas treatment with LB yielded significantly improved median MNT, VS score, and peak vertical force for up to 24 hours. DISCUSSION In this experimental model of forelimb lameness, LB provided longer analgesia when compared with BHCl and should be further investigated for treatment of pain in horses.

OBJECTIVE To investigate the ability of a proprietary antagonist of E-type prostanoid receptor (EP) 4, grapiprant, and carprofen to attenuate lameness attributable to urate-induced synovitis in dogs. ANIMALS 5 purpose-bred hound-cross dogs. PROCEDURES A blinded, 3-way crossover study was performed. Dogs received each of 3 treatments (L-766, a proprietary antagonist of EP4; 4.0 mg/kg), grapiprant (an antagonist of EP4; 2.0 mg/kg), and carprofen (4.4 mg/kg); dogs received 4 doses of each treatment (14 and 2 hours before and 22 and 46 hours after urate injection). Synovitis was induced by intra-articular injection of sodium urate. Measurements (vertical ground reaction forces and clinical lameness scores) were obtained immediately before (0 hours; baseline) and 6, 12, 24, 36, and 48 hours after sodium urate injection. All data were analyzed with repeated-measures ANOVA. RESULTS Lameness scores at 6 hours were significantly higher than baseline lameness scores for all treatments. Lameness scores for the grapiprant treatment remained significantly higher at 12 and 24 hours, compared with baseline lameness scores. Lameness scores for the carprofen treatment were significantly lower than lameness scores for the grapiprant treatment at 6, 12, and 24 hours. Analysis of peak vertical force and vertical impulse data revealed a pattern similar to that for lameness scores. Treatment with L-766 resulted in a significantly higher vertical impulse at 48 hours than did treatment with carprofen or grapiprant. CONCLUSIONS AND CLINICAL RELEVANCE In these dogs, carprofen was the most effective treatment for attenuating lameness induced by injection of sodium urate, and grapiprant was the least effective treatment.

OBJECTIVE To determine the holding capacity of a 5.5-mm-diameter cortical bone screw when placed in the third phalanx (P3) of horses and assess whether screw placement through the dorsal hoof wall into P3 would be tolerated by clinically normal horses and would alleviate signs of pain and prevent P3 rotation in horses with oligofructose-induced laminitis. ANIMALS 40 limbs from 10 equine cadavers and 19 clinically normal adult horses. PROCEDURES In part 1 of a 3-part study, a 5.5-mm-diameter cortical bone screw was inserted by use of a lag-screw technique through the dorsal hoof wall midline into P3 of 40 cadaveric limbs and tested to failure to determine screw pullout force. In part 2, 6 horses had 5.5-mm-diameter cortical bone screws placed in both forefeet as described for part 1. Screws were removed 4 days after placement. Horses were monitored for lameness before and for 2 weeks after screw removal. In part 3, 13 horses were randomly assigned to serve as controls (n = 3) or undergo screw placement without (group 2; 6) or with (group 3; 4) a washer. Following the acquisition of baseline data, horses were sedated and administered oligofructose (10 g/kg) via a stomach tube. Twenty-four hours later, screws were placed as previously described in both forefeet of horses in groups 2 and 3. Horses were assessed every 4 hours, and radiographic images of the feet were obtained at 96 and 120 hours after oligofructose administration. Horses were euthanized, and the feet were harvested for histologic examination. RESULTS The mean ± SD screw pullout force was 3,908.7 ± 1,473.4 N, and it was positively affected by the depth of screw insertion into P3. Horses of part 2 tolerated screw placement and removal well and did not become lame. All horses of part 3 developed signs of acute lameness, and the distance between P3 and the dorsal hoof wall increased slightly over time. The change in the ratio of the dorsal hoof wall width at the extensor process of P3 to that at the tip of P3 over time was the only variable significantly associated with treatment. CONCLUSIONS AND CLINICAL RELEVANCE Placement of a 5.5-mm-diameter cortical bone screw through the dorsal hoof wall into P3 had sufficient holding power to counteract the pull of the deep digital flexor tendon in approximately 500-kg horses, and placement of such a screw was well tolerated by clinically normal horses but did not alleviate signs of pain in horses with oligofructose-induced laminitis. Further research is necessary before this technique can be recommended for horses with naturally occurring acute laminitis.

OBJECTIVE To assess single-day and multiday repeatability of weight distribution (stance) data obtained with a commercial analyzer for dogs with naturally occurring hind limb lameness. ANIMALS 46 dogs (15 and 31 for single-day and multiday trials, respectively). PROCEDURES For single-day trials, 5 to 10 measurements/trial were collected to determine body weight (BW), weight distribution on each limb, and forelimb and hind limb symmetry indices (SIs). The dog was removed from the room and returned immediately; 5 trials were performed. For multiday trials, measurements were performed in the same manner on 2 sequential days. Data were compared among trials (single-day measurements) and between days (multiday measurements). Repeatability (correlation coefficients and Lin concordance correlation coefficients [LCCCs]) and variability (coefficients of variation [CVs]) were assessed. RESULTS In single-day trials, BW (r = 0.999), weight distribution on the lame hind limb (r = 0.915) and contralateral hind limb (r = 0.948), and hind limb SI (r = 0.964) were each significantly correlated among trials. In multiday trials, BW results were similar; weight distribution on the lame hind limb and contralateral hind limb and hind limb SI were each less closely but still significantly correlated between days. The LCCCs were highest for BW, weight distribution on the contralateral hind limb, and hind limb SI in single-day trials and for BW and weight bearing on the contralateral and lame hind limbs in multiday trials. The CVs were lowest for BW and highest for forelimb SI in both trial types. CONCLUSIONS AND CLINICAL RELEVANCE The analyzer used allowed repeatable measurement of BW and weight distribution on the hind limbs of dogs with hind limb lameness. Measurement of forelimb stance variables was not repeatable in this group of dogs.

OBJECTIVE To evaluate lameness and morphological changes associated with an osteochondral fragment–groove procedure as a means of experimental induction of metacarpophalangeal (MCP) joint osteoarthritis within an 11-week period in horses. ANIMALS 6 nonlame adult warmbloods. PROCEDURES The right MCP joint of each horse underwent an osteochondral fragment–groove procedure (day 0). After 1 week of stall rest (ie, starting day 7), each horse was trained daily on a treadmill. Weekly, horses underwent visual and inertial sensor-based assessments of lameness. Both MCP joints were assessed radiographically on days 0 (before surgery), 1, 35, and 77. A synovial fluid sample was collected from the right MCP joint on days 0 (before surgery), 35, 36, 49, 63, and 77 for cytologic and biomarker analyses. On day 77, each horse was euthanized; both MCP joints were evaluated macroscopically and histologically. RESULTS Right forelimb lameness was detected visually and by the inertial sensor system when horses were moving on a straight line after distal forelimb flexion or circling left on days 14 to 77. Compared with presurgical values, synovial fluid interleukin-6, prostaglandin E2, hyaluronic acid, and interleukin-1 receptor antagonist protein concentrations were increased at 2 or 3 time points, whereas tumor necrosis factor-α and interleukin-10 concentrations were decreased at 1 time point. Gross examination of all right MCP joints revealed synovitis and wear lines; synovitis was confirmed histologically. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a combined osteochondral fragment–groove procedure can be used to induce clinically and grossly observable early MCP joint osteoarthritis during an 11-week period in horses.

OBJECTIVE To compare the ability of acetaminophen-codeine (AC; 15.5 to 18.5 mg/kg and 1.6 to 2.0 mg/kg, respectively) or carprofen (4.2 to 4.5 mg/kg) administered PO to attenuate experimentally induced lameness in dogs. ANIMALS 7 purpose-bred dogs. PROCEDURES A blinded crossover study was performed. Dogs were randomly assigned to receive AC or carprofen treatment first and then the alternate treatment a minimum of 21 days later. Synovitis was induced in 1 stifle joint during each treatment by intra-articular injection of sodium urate (SU). Ground reaction forces were assessed, and clinical lameness was scored at baseline (before lameness induction) and 3, 6, 9, 12, 24, 36, and 48 hours after SU injection. Plasma concentrations of acetaminophen, carprofen, codeine, and morphine were measured at various points. Data were compared between and within treatments by repeated-measures ANOVA. RESULTS During AC treatment, dogs had significantly higher lameness scores than during carprofen treatment at 3, 6, and 9 hours after SU injection. Peak vertical force and vertical impulse during AC treatment were significantly lower than values during carprofen treatment at 3, 6, and 9 hours. Plasma concentrations of carprofen (R)- and (S)-enantiomers ranged from 2.5 to 19.2 μg/mL and 4.6 to 25.0 μg/mL, respectively, over a 24-hour period. Plasma acetaminophen concentrations ranged from 0.14 to 4.6 μg/mL and codeine concentrations from 7.0 to 26.8 ng/mL, whereas plasma morphine concentrations ranged from 4.0 to 58.6 ng/mL. CONCLUSIONS AND CLINICAL RELEVANCE Carprofen as administered was more effective than AC at attenuating SU-induced lameness in dogs.

OBJECTIVE To evaluate the analgesic and tissue effects of liposomal bupivacaine administered SC as an abaxial sesamoid nerve block in horses with experimentally induced lameness. ANIMALS 6 healthy mature light-breed horses. PROCEDURES In a randomized crossover study, a circumferential hoof clamp was applied to a forelimb to induce reversible lameness. An abaxial sesamoid nerve block of the lame forelimb was performed by SC perineural injection of 10 mg of liposomal bupivacaine or bupivacaine HCl/site. Quantitative gait data were objectively obtained with a body-mounted inertial sensor system before (baseline) and at 30-minute intervals after treatment. Time to return to 85% of baseline lameness was determined. After a minimum 4-day washout period, procedures were repeated with the alternate limb and treatment. Lastly, the palmar digital nerves and perineural tissues were collected and examined histologically. RESULTS SC perineural injection of liposomal bupivacaine ameliorated forelimb lameness in 5 of 6 horses. The median duration of analgesia was not significantly different between liposomal bupivacaine (4.5 hours) and bupivacaine HCl (3.0 hours). Histologically, mild inflammation was noted in 3 of 10 sites injected with liposomal bupivacaine and in none of the sites injected with bupivacaine HCl. CONCLUSIONS AND CLINICAL RELEVANCE SC perineural injection of 10 mg of liposomal bupivacaine/site ameliorated experimentally induced forelimb lameness in some horses. At milligram-equivalent doses, liposomal bupivacaine had a similar duration of analgesia to that of bupivacaine HCl. Further investigation is required before recommending clinical use of liposomal bupivacaine for nerve blocks in horses.

OBJECTIVE To determine variance effects influencing ground reaction forces (GRFs) in a heterogeneous population of lame dogs during trotting. ANIMALS 30 client-owned dogs with thoracic limb lameness and 31 dogs with pelvic limb lameness. PROCEDURES GRFs, velocity, height at the dorsal aspect of the scapulae (ie, withers), and shoulder height were obtained. Each dog was trotted across a force platform at its preferred velocity. Variance effects for 12 velocity and associated relative velocity (V*) ranges were examined. RESULTS Individual dog, velocity, V*, and limb significantly influenced GRFs. Withers height V* ranges were associated with small variance in GRFs, but all absolute and V* ranges were associated with significant effects for all 4 limbs and both types of lameness. Significant changes in lame limb GRFs and velocity in ipsilateral trials in dogs with thoracic limb and pelvic limb lameness were evident with trial repetition. Withers height V* range of 0.55 to 0.93 captured a large proportion of trials (> 90%) in dogs with thoracic limb or pelvic limb lameness, with limited effects on peak vertical force and vertical impulse. CONCLUSIONS AND CLINICAL RELEVANCE Trial repetition caused alterations to GRFs and subject velocity that may have confounded assessment of lameness, which supported the concept that a priori selection of a velocity or V* range for force platform gait analysis should use a range that captures valid trials efficiently while minimizing GRF variance. These ranges typically would span the preferred velocity of subject dogs, such as withers height V* of 0.55 to 0.93.

OBJECTIVE To evaluate the effects of exercise in an underwater treadmill (UWT) on forelimb biomechanics and articular histologic outcomes in horses with experimentally induced osteoarthritis of the middle carpal joint. ANIMALS 16 horses. PROCEDURES An osteochondral fragment was induced arthroscopically (day 0) in 1 middle carpal joint of each horse. Beginning on day 15, horses were assigned to exercise in a UWT or in the UWT without water (simulating controlled hand walking) at the same speed, frequency, and duration. Thoracic and pelvic limb ground reaction forces, thoracic limb kinematics, and electromyographic results for select thoracic limb muscles acting on the carpi were collected on days -7 (baseline), 14, 42, and 70. Weekly evaluations included clinical assessments of lameness, response to carpal joint flexion, and goniometric measurements of thoracic limb articulations. At study conclusion, articular cartilage and synovial membrane from the middle carpal joints was histologically examined. RESULTS Exercise in a UWT significantly reduced synovial membrane inflammation and resulted in significant clinical improvements with regard to symmetric thoracic limb loading, uniform activation patterns of select thoracic limb muscles, and return to baseline values for carpal joint flexion, compared with results for horses with simulated hand walking. CONCLUSIONS AND CLINICAL RELEVANCE Overall improvements in thoracic limb function, joint range of motion, and synovial membrane integrity indicated that exercise in a UWT was a potentially viable therapeutic option for the management of carpal joint osteoarthritis in horses.

To determine the effects of 3 α17 adult polo horses with naturally occurring forelimb or hind limb lameness (or both).In a crossover design, each horse received each protocol (saline [0.09% NaCl] solution [2 mL, IV] or xylazine hydrochloride [0.33 mg/kg, IV], detomidine hydrochloride [0.007 mg/kg, IV], or romifidine hydrochloride [0.033 mg/kg, IV] alone or in combination with butorphanol [0.007 mg/kg, IV]) in random order, with a washout period (≥ 7 days) between protocols. Horses were assessed immediately prior to (baseline) and 10, 15, 20, 30, and 40 minutes after administration of each protocol for degree of sedation, mechanical nociceptive threshold (MNT), and objective lameness measurements.Compared with baseline values, sedation scores and MNTs were significantly higher at all evaluated time points following administration of all sedation protocols except xylazine alone; following administration of xylazine alone, sedation scores and MNTs were significantly higher at ≤ 30 minutes and ≤ 20 minutes, respectively. Significant differences in objective forelimb lameness measurements were noted after administration of the 3 αIn the study horses, xylazine alone had the least impact on objective lameness measurements. The administration of α

OBJECTIVE To evaluate the biomechanical properties of 4 methods for fusion of the centrodistal and tarsometatarsal joints in horses and compare them among each other and with control tarsi. SAMPLE 24 sets of paired tarsi without substantial signs of osteoarthritis harvested from equine cadavers. PROCEDURES Test constructs (n = 6/type) were prepared from 1 tarsus from each pair to represent surgical drilling; 2 medially to laterally placed kerf-cut cylinders (MLKCs); a single large, dorsally applied kerf-cut cylinder (DKC); and a dorsomedially applied locking compression plate (DMLCP). Constructs and their contralateral control tarsi were evaluated in 4-point bending in the dorsoplantar, lateromedial, and mediolateral directions; internal and external rotation; and axial compression. Bending, torsional, and axial stiffness values were calculated. RESULTS Mean stiffness values were consistently lower for surgical drilling constructs than for contralateral control tarsi. Over all biomechanical testing, surgical drilling significantly reduced joint stability. The MLKC constructs had superior biomechanical properties to those of control tarsi for 4-point bending but inferior properties for external and internal rotation. The DMLCP and DKC constructs were superior to control tarsi in dorsoplantar, rotational, and axial compression directions only; DMLCP constructs had no superior stiffness in lateromedial or mediolateral directions. Only the DKC constructs had greater stiffness in the mediolateral direction than did control tarsi. Over all biomechanical testing, DMLCP and DKC constructs were superior to the other constructs. CONCLUSIONS AND CLINICAL RELEVANCE These biomechanical results suggested that a surgical drilling approach to joint fusion may reduce tarsal stability in horses without clinical osteoarthritis, compared with stability with no intervention, whereas the DMLCP and DKC approaches may significantly enhance stability.

OBJECTIVE To evaluate head, pelvic, and limb movement to detect lameness in galloping horses. ANIMALS 12 Thoroughbreds. PROCEDURES Movement data were collected with inertial sensors mounted on the head, pelvis, and limbs of horses trotting and galloping in a straight line before and after induction of forelimb and hind limb lameness by use of sole pressure. Successful induction of lameness was determined by measurement of asymmetric vertical head and pelvic movement during trotting. Differences in gallop strides before and after induction of lameness were evaluated with paired-sample statistical analysis and neural network training and testing. Variables included maximum, minimum, range, and time indices of vertical head and pelvic acceleration, head rotation in the sagittal plane, pelvic rotation in the frontal plane, limb contact intervals, stride durations, and limb lead preference. Difference between median standardized gallop strides for each limb lead before and after induction of lameness was calculated as the sum of squared differences at each time index and assessed with a 2-way ANOVA. RESULTS Head and pelvic acceleration and rotation, limb timing, stride duration measurements, and limb lead preference during galloping were not significantly different before and after induction of lameness in the forelimb or hind limb. Differences between limb leads before induction of lameness were similar to or greater than differences within limb leads before and after lameness induction. CONCLUSIONS AND CLINICAL RELEVANCE Galloping horses maintained asymmetry of head, pelvic, and limb motion between limb leads that was unrelated to lameness.

OBJECTIVE To determine effects for 2 IV regional limb perfusion (IVRLP) protocols involving tiludronate on lameness of horses with navicular syndrome. ANIMALS 15 horses with bilateral forelimb navicular syndrome. PROCEDURES Shoeing and anti-inflammatory injection into the distal interphalangeal joint (DIPJ) of both forelimbs (day 0) were performed on all horses. On day 14, horses received 1 of 3 IVRLPs consisting of 0.1 mg of tiludronate/kg (low-dose tiludronate [LDT]; n = 5), 0.2 mg of tiludronate/kg (high-dose tiludronate [HDT]; 5), or saline (0.9% NaCl) solution (placebo; 5); treatments were repeated at days 24 and 34. Lameness severity of both forelimbs was evaluated via subjective evaluation and force plate analysis before and after shoeing on day 0 and at days 14, 34, 60, and 120. Mean subjective lameness score and peak vertical ground reaction force (PVGRF) for the more severely lame forelimb (LFL) and both (combined) forelimbs (CFL) were compared over time. RESULTS For all horses, mean PVGRF for the LFL and CFL was increased at 14 days. No difference in mean subjective lameness score or mean PVGRF was detected within groups at any time. Mean PVGRF of the CFL was higher for the HDT group than the LDT and placebo groups only at 120 days. CONCLUSIONS AND CLINICAL RELEVANCE Use of the tiludronate IVRLP protocols described here provided no further improvement in lameness over therapeutic shoeing and anti-inflammatory injection of the DIPJ in horses with navicular syndrome. However, HDT-treated horses were objectively less lame than LDT- or placebo-treated horses at 120 days.

OBJECTIVE To determine whether addition of epinephrine to a lidocaine solution would prolong and potentiate the efficacy of a palmar digital nerve block (PDNB) in horses. ANIMALS 6 adult horses with naturally occurring forefoot lameness. PROCEDURES Initially, a PDNB with a 2% lidocaine solution was performed on the affected foot of each horse. Three days later, the PDNB was repeated with a 1% lidocaine solution or a 1% lidocaine solution containing epinephrine (dilution, 1:200,000). After another 3-day washout period, the PDNB was repeated with the treatment opposite that administered for the second PDNB. Gait was analyzed with a computerized lameness analysis system and heart rate and extent of skin sensation between the heel bulbs of the blocked foot were evaluated at predetermined times for 2 hours after each PDNB. RESULTS Efficacy and duration of the PDNB did not differ significantly between the 2% and 1% lidocaine treatments. The addition of epinephrine to the 1% lidocaine solution improved the efficacy and prolonged the duration of the PDNB. It also resulted in a positive correlation between skin desensitization and amelioration of lameness. Median heart rate remained unchanged throughout the observation period for all 3 treatments. No adverse effects associated with the PDNBs were observed. CONCLUSIONS AND CLINICAL RELEVANCE Addition of epinephrine (dilution, 1:200,000) to a 1% lidocaine solution improved the efficacy and prolonged the duration of a PDNB in horses with naturally occurring lameness and might be clinically useful for lameness evaluations and standing surgery of the forefoot of horses.

OBJECTIVE To evaluate clinical and tenoscopic findings in a large group of horses undergoing surgery of the carpal flexor sheath (CFS) and determine whether any of the presurgical clinical signs were associated with tenoscopic findings. ANIMALS 242 horses that had undergone diagnostic and therapeutic tenoscopy of the CFS because of aseptic tenosynovitis. PROCEDURES Medical and tenoscopic video records (when available) of 242 horses undergoing tenoscopy of the CFS at a single equine clinic between January 2005 and June 2014 were reviewed. Tenoscopic findings were categorized as present or absent, and tears in the deep digital flexor tendon (DDFT) were subjectively graded according to severity. Logistic regression analysis was used to examine whether presurgical clinical findings were associated with intraoperative tenoscopic findings. RESULTS 242 horses (411 limbs) were evaluated by use of tenoscopy. An exostosis was detected in 228 horses (379 limbs) and was often multipartite. Most exostoses were found medial to, or within, the sagittal plane at the caudal margin of the scar on the distal physis of the radius. Effusion in the CFS was associated with tears in the DDFT. Other presurgical clinical findings were not predictive of intrathecal findings. CONCLUSIONS AND CLINICAL RELEVANCE Synovial effusion was predictive of DDFT lesions within the CFS but was not predictive of the severity of lesions. Further studies will be necessary to determine whether any tenoscopic findings are associated with reduced athletic performance and to assess the effect of surgical intervention in affected horses.

Objective—To evaluate intra-articular autologous protein solution (APS) for the treatment of osteoarthritis in horses. Animals—40 client-owned horses with naturally occuring osteoarthritis. Procedures—APS was generated from a dual-device system that concentrated plasma and WBC proteins and enriched platelet growth factors. Horses were randomly assigned to receive an intra-articular injection of 5 mL of saline (0.9% NaCl) solution (n = 20) or APS (20), exercised on a treadmill, and evaluated on the basis of lameness grades, kinetic gait analysis, joint circumference, and range of motion for 14 days. Horses that received saline solution were administered APS at termination of the study, and clients scored horses for lameness and discomfort before, 12 weeks after, and 52 weeks after the APS injection. Results—The APS group had significant improvements in lameness grade, asymmetry indices of vertical peak force, and range of joint motion by 14 days, compared with baseline or control group values. No adverse effects associated with APS treatment were evident. Clients assessed lameness and comfort as improved at 12 and 52 weeks. The APS had greater likelihood (OR, 4.3 to 30.0) of a therapeutic response in horses with a lameness score < 4, < 10% vertical force asymmetry, or absence of marked osteophyte formation, subchondral sclerosis, or joint space narrowing. Concentration of interleukin-1 receptor antagonist in APS was 5.8 times that in blood. Conclusions and Clinical Relevance—Intra-articular administration of APS can be considered an effective treatment option for equine osteoarthritis, with the potential for disease-modifying effects.

Objective—To evaluate the load redistribution mechanisms in walking and trotting dogs with induced forelimb lameness. Animals—7 healthy adult Beagles. Procedures—Dogs walked and trotted on an instrumented treadmill to determine control values for peak and mean vertical force as well as verticle impulse for all 4 limbs. A small sphere was attached to the ventral pad of the right forelimb paw to induce a reversible lameness, and recordings were repeated for both gaits. Additionally, footfall patterns were assessed to test for changes in temporal gait variables. Results—During walking and trotting, peak and mean vertical force as well as vertical impulse were decreased in the ipsilateral forelimb, increased in the contralateral hind limb, and remained unchanged in the ipsilateral hind limb after lameness was induced. All 3 variables were increased in the contralateral forelimb during trotting, whereas only mean vertical force and vertical impulse were increased during walking. Stance phase duration increased in the contralateral forelimb and hind limb during walking but not during trotting. Conclusions and Clinical Relevance—Analysis of the results suggested that compensatory load redistribution mechanisms in dogs depend on the gait. All 4 limbs should be evaluated in basic research and clinical studies to determine the effects of lameness on the entire body. Further studies are necessary to elucidate specific mechanisms for unloading of the affected limb and to determine the long-term effects of load changes in animals with chronic lameness.

OBJECTIVE To evaluate the efficacy of IV administration of a product containing hyaluronan, sodium chondroitin sulfate, and N-acetyl-d-glucosamine for prevention or treatment of osteoarthritis in horses. ANIMALS 32 healthy 2- to 5-year-old horses. PROCEDURES The study involved 2 portions. To evaluate prophylactic efficacy of the test product, horses received 5 mL of the product (n = 8) or saline (0.9% NaCl) solution (8; placebo) IV every fifth day, starting on day 0 (when osteoarthritis was induced in the middle carpal joint of 1 forelimb) and ending on day 70. To evaluate treatment efficacy, horses received either the product or placebo (n = 8/treatment) on days 16, 23, 30, 37, and 44 after osteoarthritis induction. Clinical, diagnostic imaging, synovial fluid, gross anatomic, and histologic evaluations and other tests were performed. Results of each study portion were compared between treatment groups. RESULTS Limb flexion and radiographic findings were significantly worse for horses that received the test product in the prophylactic efficacy portion than for placebo-treated horses or product-treated horses in the treatment efficacy portion. In the prophylactic efficacy portion, significantly less articular cartilage erosion was identified in product-treated versus placebo-treated horses. In the treatment efficacy portion, joints of product-treated horses had a greater degree of bone edema identified via MRI than did joints of placebo-treated horses but fewer microscopic articular cartilage abnormalities. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that caution should be used when administering the evaluated product IV to horses, particularly when administering it prophylactically, as it may have no benefit or may even cause harm.

OBJECTIVE To determine effects of 2 tiludronate administration protocols on measures of lameness in horses with navicular syndrome (NS). ANIMALS 12 horses with bilateral forelimb NS. PROCEDURES Horses were randomly assigned to receive tiludronate (1 mg/kg), diluted in 5 L of isotonic electrolyte solution and delivered through a jugular vein catheter (systemic treatment group; n = 6), or tiludronate (0.1 mg/kg), diluted with saline (0.9% NaCl) solution to a total volume of 35 mL and delivered into the lateral digital vein of each forelimb with an IV regional limb perfusion (IVRLP) technique (IVRLP group; 6). Mean peak vertical ground reaction force (pVGRF) measured with a stationary force plate and subjective lameness scores (SLSs) were recorded before (day −1) and at predetermined time points after tiludronate administration on day 0. Mean pVGRFs (standardized as percentage body weight of force) and mean SLSs for the most lame forelimb and for both forelimbs of horses in each group were compared with day −1 values to determine treatment effect. RESULTS Mean pVGRF for both forelimbs and for the most lame forelimbs of systemically treated horses were significantly increased on days 120 and 200, compared with day −1 results. No significant difference in mean pVGRF was observed for IVRLP-treated horses. The SLSs were not improved at any time point following systemic treatment and were improved only on day 120 following IVRLP. CONCLUSIONS AND CLINICAL RELEVANCE Tiludronate (1 mg/kg, IV) as a single systemic treatment appeared to be beneficial for horses with NS, but no horses were judged as sound during the study period. Additional research on IVRLP with tiludronate is needed before this method can be recommended. (Am J Vet Res 2016;77:167–173)

OBJECTIVE To investigate associations between inertial sensor and stationary force plate measurements of hind limb lameness in horses. ANIMALS 21 adult horses with no lameness or with mild hind limb lameness. PROCEDURES Horses were instrumented with inertial sensors and evaluated for lameness with a stationary force plate while trotting in a straight line. Inertial sensor–derived measurements of maximum and minimum pelvic height differences between right and left halves of the stride were compared with vertical and horizontal ground reaction forces (GRFs). Stepwise linear regression was performed to investigate the strength of association between inertial sensor measurements of hind limb lameness and amplitude, impulse, and time indices of important events in the vertical and horizontal GRF patterns. RESULTS Difference in minimum pelvic position was moderately (Ra2 = 0.60) associated with the difference in peak vertical GRF but had little association with any horizontal GRF measurements. Difference in maximum pelvic position was strongly (Ra2 = 0.77) associated with a transfer of vertical to horizontal ground reaction impulse in the second half of the stance but was not associated with difference in peak vertical GRF. CONCLUSIONS AND CLINICAL RELEVANCE Inertial sensor–derived measurements of asymmetric pelvic fall (difference in minimum pelvic position) indicated a decrease in vertical GRF, but similar measurements of asymmetric pelvis rise (difference in maximum pelvic position) indicated a transfer of vertical to horizontal force impulse in the second half of the stance. Evaluation of both pelvic rise and fall may be important when assessing hind limb lameness in horses.

Objective—To generate data on the effects of firocoxib administration to horses with osteoarthritis. Animals—Client-owned horses with signs of lameness and joint pain associated with osteoarthritis. Procedures—Firocoxib was administered as an oral paste (0.1 mg/kg, q 24 h) for 14 days. Assessments were performed on day 0 (baseline) and days 7 and 14. Results—390 of 429 horses from 80 sites in 25 states met the criteria for analysis. Quarter Horse and Thoroughbred were the 2 most commonly represented breeds, comprising half of the study population. Signs of musculoskeletal pain or lameness attributed to osteoarthritis were diagnosed in a single joint in 197 (197/390 [50.5%]) horses and in multiple joints in 193 (193/390 [49.5%]) horses. In those with involvement of a single joint, the tarsus was the most frequently affected joint (79/197 [40.1 %]). Among the 390 horses with complete lameness data, improvement was reported in approximately 80% by day 14. Investigators rated 307 (78.7%) horses as improved, whereas owners or handlers rated 316 (81.0%) horses as improved at the termination of the study. Horses treated with firocoxib paste had significant improvement in lameness scores from baseline values. Improvement was most rapid within the first 7 days after starting treatment and continued, albeit at a slower rate, through treatment day 14. Conclusions and Clinical Relevance—Firocoxib significantly improved lameness scores throughout the 14-day period with few adverse effects. Firocoxib can be a safe cyclooxygenase-2–specific NSAID for the treatment of musculoskeletal pain and lameness associated with osteoarthritis.

Objective—To characterize amphotericin B–induced lameness in cattle and to ascertain the analgesic effects of flunixin meglumine by use of multimodal assessment. Animals—10 healthy Holstein steers free from musculoskeletal disease. Procedures—Steers were randomly allocated to a treatment or negative control group. Amphotericin B was injected into the distal interphalangeal joint of the lateral claw of the left hind limb of all steers. Treatment steers received flunixin meglumine at the time of synovitis-arthritis induction and at 12 hours after induction. Control steers received no medication. Multimodal analysis included vital parameters, visual lameness score, behavioral monitoring with accelerometers, pressure mat analysis, and plasma cortisol determination before and after induction. Data were analyzed by use of linear mixed models with treatment and time designated as fixed effects, accounting for repeated measures on individual calves. Results—Amphotericin B injection induced moderate, transient lameness. Control steers were more than twice as likely to be lame as treatment steers (mean ± SD lameness score, 92.2 ± 8.1 % vs 40.7 ± 2.5%). Treatment steers placed significantly greater force and contact area on the affected foot and greater force, impulse, and contact area on the paired claw, compared with control steers. Furthermore, treatment steers spent considerably less time in recumbency than controls. Conclusions and Clinical Relevance—Amphotericin B successfully induced synovitis-arthritis in dairy steers that was transient in nature. Flunixin meglumine was efficacious in providing analgesia for these steers.

Objective—To develop a parsimonious statistical model to predict incidence of lameness in the subsequent lactation by use of data collected at cessation of lactation in dairy cows. Animals—574 cows. Procedures—At cessation of lactation during hoof trimming, body condition score (BCS), visual locomotion score, digital cushion thickness (DCT), and digital lesions were assessed. Results—140 (24%) cows were treated for claw horn disruption lesions (CHDLs) at cessation of lactation (114 with sole ulcers [pododermatitis circumscripta] and 26 with white line disease). The BCS was highly associated with DCT. Cows with CHDLs at cessation of lactation had significantly lower DCT, compared with other cows. All 3 logistic regression models predicted the incidence of CHDLs in the subsequent lactation with good accuracy; the area under the receiver operating characteristic curves was 0.76, 0.76, and 0.77 for the first, second, and third logistic regression models, respectively. Conclusion and Clinical Relevance—Evaluation of 3 logistic regression models indicated that lameness could be predicted with good accuracy by use of all 3. The ability to predict lameness will facilitate the implementation of lameness prevention strategies by targeting specific cows.

Objective—To investigate the ability of perzinfotel (an N-methyl-d-aspartate receptor antagonist) and a proprietary phospholipase A2 (PLA2) inhibitor to attenuate lameness in dogs with sodium urate (SU)–induced synovitis. Animals—8 adult dogs. Procedures—A blinded 4-way crossover study was performed. Dogs received perzinfotel (10 mg/kg), a proprietary PLA2 inhibitor (10 mg/kg), carprofen (4.4 mg/kg; positive control treatment), or no treatment (negative control treatment). On the fourth day after initiation of treatment, synovitis was induced via intra-articular injection of SU 1 hour before administration of the last treatment dose. Ground reaction forces were measured and clinical lameness evaluations were performed before (baseline [time 0]) and 2, 4, 6, 8, 12, and 25 hours after SU injection. There was a 21-day washout period between subsequent treatments. Data were analyzed via repeated-measures ANOVAs. Results—Peak vertical force (PVF) and vertical impulse (VI) values for negative control and perzinfotel treatments were significantly lower at 2 and 4 hours, compared with baseline values. Values for PVF and VI for the PLA2 inhibitor and positive control treatments did not differ from baseline values at any time points. Between-treatment comparisons revealed significantly higher PVF and VI values for the positive control treatment than for the negative control and perzinfotel treatments at 2 and 4 hours. Values for VI were higher for PLA2 inhibitor treatment than for negative control treatment at 2 hours. Conclusions and Clinical Relevance—Perzinfotel did not significantly alter SU–induced lameness. The proprietary PLA2 inhibitor attenuated lameness but not as completely as did carprofen.

Objective—To determine the accuracy of pressure plate kinetic asymmetry indices (ASIs) for diagnosis of unilateral hind limb lameness in dogs and their correlation with visual gait assessment (VGA) scores. Animals—9 healthy dogs and 16 dogs with previously diagnosed unilateral rupture of the cranial cruciate ligament and concurrent unilateral hind limb lameness. Procedures—Dogs were walked over a pressure plate to determine paw contact area (PCA), peak vertical pressure (PVP), peak vertical force (PVF), and vertical impulse (VI) of both hind limbs. An ASI was calculated for each gait variable. Simultaneously, gait was assessed visually and scored by use of a numeric rating scale (0 to 10). The ASI of each variable was tested for its usefulness in discrimination between lame and nonlame dogs and for correlation with VGA scores. Results—Sensitivity and specificity of ASIs to discriminate between lame and nonlame dogs were excellent for PVF, VI, and PCA; these values were substantially lower for ASI of PVP. Cutoff values to discriminate between lame and nonlame dogs were determined by use of ASIs for PVF, VI, and PCA; however, this could not be done for ASI of PVP. Correlations between ASIs of PVF, VI, and PCA and VGA scores were higher than correlation between the ASIs of PVP and VGA scores. Conclusions and Clinical Relevance—Results indicated that ASIs of PVF and VI determined via analysis of pressure plate measurements were reliable indicators of clinical lameness in dogs, but the ASI of PVP was not. The ASI of PCA is an interesting new variable for assessment of limb loading symmetry.

Objective—To investigate the effects of heparin administration on urine protein excretion during the developmental stages of experimentally induced laminitis in horses. Animals—13 horses. Procedures—Horses received unfractionated heparin (80 U/kg, SC, q 8 h; n = 7) or no treatment (control group; 6) beginning 3 days prior to induction of laminitis. All horses were given 3 oligofructose loading doses (1 g/kg each) at 24-hour intervals and a laminitis induction dose (10 g of oligofructose/kg) 24 hours following the final loading dose (designated as 0 hours) via nasogastric tube. Serum glucose and insulin concentrations were measured before administration of the first loading dose (baseline) and at 0 and 24 hours; urine protein-to-creatinine (UP:C) ratio was determined at 0 hours and every 4 hours thereafter. Lameness was evaluated every 6 hours, and horses were euthanized when Obel grade 2 ameness was observed. Results—Mean ± SD time until euthanasia did not differ significantly between the heparin-treated (28.9 ± 6.5 hours) and control (29.0 ± 6.9 hours) horses. The UP:C ratio was significantly increased from baseline at 20 to 28 hours after induction of laminitis (ie, 4 ± 4 hours before lameness was evident) in control horses but did not change significantly from baseline in heparin-treated horses. Serum glucose or insulin concentration did not change significantly from baseline in either group. Conclusions and Clinical Relevance—Urine protein excretion increased during the developmental stages of carbohydrate-induced laminitis in horses; administration of heparin prevented that increase, but did not delay onset or decrease severity of lameness.

Evaluation of radiographic and genetic aspects of hereditary subluxation of the radial head in Bouviers des Flandres. Summary Objective-To study radiographic and genetic aspects of hereditary radial head subluxation in Bouviers des Flandres. Animals-26 related Bouviers des Flandres affected with bilateral subluxation of the radial head, 10 unaffected related dogs, and 29 unrelated Bouviers des Flandres with diagnoses of nonskeletal diseases. Procedures-All dogs were radiographically studied, and their DNA was analyzed with a genome-wide screen of 1,536 single nucleotide polymorphisms. In addition, karyotyping was performed in an unaffected dam and its affected offspring. Results-Both forelimbs of affected dogs were disproportionately short with caudolateral subluxation or luxation of the radial head. Angulation of the radial axis at the mid-diaphysis ranged from 9.3 degrees to 30.3 degrees (mean +/- SD, 14.9 +/- 6.1 degrees ), with an estimated age of onset from 0 to 4 months. Poorly defined medial coronoid processes and osteoarthritis of the elbow joint, cranial bowing of the olecranon, and disturbed growth in length of the ulna with sharply demarcated spurs were noticed on radiographs of affected dogs. Genealogical analysis indicated that most affected dogs were closely related, but the mode of inheritance was not clear. The DNA analysis found that 205 single nucleotide polymorphisms were monomorphic in the affected dogs. Conventional chromosome staining revealed no numerical chromosomal aberration. Conclusions and Clinical Relevance-Congenital radial head luxation and subluxation in the studied Bouviers des Flandres were characterized by angulation of the radial axis leading to caudolateral subluxation of the radial head and insufficient growth of the distal portion of the ulna together with cranial bowing of the olecranon. Affiliation Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, 3584 CM, Utrecht, The Netherlands. Journal Details Name: American journal of veterinary research ISSN: 0002-9645 Pages: 884-90

Objective—To provide insights into the role of prostaglandin F2α (PGF2α) in the developmental stages of laminitis induced in horses by ingestion of black walnut heartwood extract (BWHE). Sample Population—10 adult mixed-breed horses. Procedures—Horses were separated into 2 groups and were euthanatized at 12 hours after placebo (water) administration (control horses) or after BWHE administration and development of Obel grade 1 laminitis. Blood samples were obtained to determine plasma PGF2α concentrations hourly for the first 4 hours and subsequently every 2 hours after substance administration. Laminar arteries and veins were isolated, and responses to increasing concentrations of PGF2α were measured before and after preincubation of blood vessels with prostanoid and thromboxane receptor antagonists SQ 29,548, SC-19220, and AH 6809. Results—Plasma PGF2α concentrations increased in horses given BWHE; the WBC count decreased concurrently. In control horses, PGF2α was a potent contractile agonist for laminar veins but not for laminar arteries. In horses given BWHE, PGF2α was similarly selective for laminar veins; however, the magnitude of PGF2α-induced venoconstriction was less than that in control horses. After preincubation with SQ 29,548, laminar veins from control horses responded to PGF2α with a small degree of dilation, whereas laminar veins from horses given BWHE did not. Conclusions and Clinical Relevance—PGF2α may play a role in the inflammatory and vascular dysfunction associated with the prodromal stages of laminitis. Prostanoids such as PGF2α may be viable targets for the prevention of acute laminitis in horses.

Objective—To compare the effects of intra-articular (IA) versus IV administration of morphine on local and systemic inflammatory responses in horses with experimentally induced acute synovitis. Animals—8 horses. Procedures—Each horse received the following 2 treatments 4 hours after synovitis was induced: IA administration of morphine (0.05 mg/kg) with IV administration of 1 mL of saline (0.9% NaCl) solution/100 kg, and IA administration of 1 mL of saline solution/100 kg with IV administration of morphine (0.05 mg/kg). Treatments were administered in randomized order with a washout period of 3 weeks between treatments. Before each treatment, aseptic synovitis was induced by injection of lipopolysaccharide into a radiocarpal joint. For the second treatment, the contralateral radiocarpal joint was selected. Joint swelling and skin temperature over the treated joints were recorded. Clinical examinations were performed, and blood WBC count, serum amyloid A (SAA) concentration, serum cortisol concentration, synovial fluid WBC count, synovial fluid total protein (TP) concentration, and synovial fluid SAA concentration were measured before and repeatedly during each of the two 168-hour study periods. Data were analyzed by use of ANOVA with repeated measures. Results—IA administration of morphine resulted in significantly less joint swelling and lower synovial fluid TP and serum and synovial fluid SAA concentrations, and blood WBC count than did IV administration of morphine. Conclusions and Clinical Relevance—IA administration of morphine exerted anti-inflammatory properties in horses with experimentally induced acute synovitis, supporting its use as a part of a balanced analgesic protocol.

Objective—To develop a scoring system for histopathologic changes in the synovium of tarsocrural joints (TCJs) of horses with osteochondritis dissecans (OCD) and to test for association between histopathologic changes and joint effusion or lameness. Animals—93 horses with OCD of the intermediate ridge of the tibia of 1 or both TCJs (134 joints) and 38 control horses without disease of TCJs (38 joints). Procedures—For OCD-affected horses, pretreatment lameness, TCJ effusion, and results of pelvic limb flexion test were scored. Synovial biopsy specimens were obtained from TCJs of OCD-affected horses during arthroscopy, and similar postmortem tissue specimens were obtained from control horses through a small arthrotomy. Histologic signs of synovitis in 172 biopsy specimens were scored by 2 pathologists (A and B) by use of 2 criteria: synoviocyte proliferation and cellular infiltration. Results—Analysis of scoring revealed good to very good intraobserver agreement within pathologist A (weighted kappa [WK], 0.76 to 0.81), and moderate to good agreement within pathologist B (WK, 0.56 to 0.63). Interobserver agreement for synoviocyte proliferation (WK, 0.34 to 0.52) and cellular infiltration (WK, 0.38 to 0.48) scores was fair to moderate. Joint effusion and synoviocyte proliferation were significantly associated, as were joint effusion and cellular infiltration. There was no association between histopathologic changes and the other clinical signs evaluated. Conclusions and Clinical Relevance—The scoring system was helpful for evaluating synovial inflammation caused by OCD of the intermediate ridge of the tibia in horses. Histopathologic signs of synovial inflammation were associated with effusion but not with lameness.

Objective—To evaluate the applicability of Fourier analysis for assessment of ground reaction forces (GRFs) and differentiation between dogs with unilateral hind limb lameness caused by degenerative joint disease of the hip (DJD-H) and dogs without lameness. Animals—37 dogs with or without unilateral DJD-H. Procedures—Data were obtained from other studies and analyzed retrospectively. Among the 37 dogs, 20 had unilateral DJD-H and 9 (non–Belgian Malinois breeds) had no lameness; another 8 were nonlame Belgian Malinois (radiographically confirmed Fédération Cinologique International classification A [ie, no hip dysplasia or DJD-H]). Gait data acquisition was performed as dogs walked on a treadmill with integrated force platforms. The peak vertical force, mean vertical force, and vertical impulse were compared among the 3 groups. Fourier analysis was performed on the force-time curves for the vertical GRF, and calculated Fourier coefficients were compared within and between groups. Results—Lameness in the hind limbs with DJD-H was detectable via conventional analysis of the GRF as well as via Fourier analysis. However, subtle gait aberrations in the forelimbs of the dogs with DJD-H were detected solely via Fourier analysis of GRFs and remained undetected via conventional analysis. Conclusions and Clinical Relevance—Results support the applicability of Fourier analysis for evaluation of force-time curves of GRFs. Fourier analysis can reveal subtle alterations of gait that might otherwise remain inapparent; however, further investigation is necessary before this method can be routinely applied for lameness detection in dogs.

Objective—To assess analgesia, inflammation, potency, and duration of action associated with intra-articular injection of triamcinolone acetonide (TA), mepivacaine hydrochloride, or both in metacarpophalangeal (MCP) joints of horses with experimentally induced acute synovitis. Animals—18 horses. Procedures—Both forelimbs of each horse were injected with lipopolysaccharide (LPS) 3 times. After the first LPS injection, 1 forelimb of each horse was treated with intra-articular injection of mepivacaine (80 mg; n = 6), TA (9 mg; 6), or mepivacaine with TA (same doses of each; 6) 12 hours after the initial LPS injection. Contralateral limbs served as control limbs. Joint pain was assessed via lameness score and measurements of vertical force peak and pain-free range of motion of the MCP joint. Periarticular edema was evaluated. Degree of synovial inflammation was determined via synovial fluid analysis for WBC count and total protein concentration. Samples of plasma and synovial fluid were analyzed for TA and mepivacaine concentrations. Results—Each injection of LPS induced lameness and joint inflammation. Mepivacaine effectively eliminated lameness within 45 minutes after injection, regardless of whether TA was also administered, whereas TA reduced lameness, edema, and concentration of synovial fluid protein after the second LPS injection, regardless of whether mepivacaine was also injected. Treatment with TA also induced higher WBC counts and mepivacaine concentrations in synovial fluid, compared with results for mepivacaine alone. Conclusions and Clinical Relevance—Results suggested TA is a potent analgesic and anti-inflammatory medication for acute synovitis in horses and that simultaneous administration of mepivacaine does not alter the potency or duration of action of TA.

Objectives—To establish reference mechanical nociceptive threshold (MNT) values of the equine thoracic limb and to assess the use of MNT values to detect pain associated with induced osteoarthritis in the middle carpal joint. Animals—24 adult horses. Procedures—MNT values were evoked by a pressure algometer at 17 sites within each thoracic limb during 2 baseline sessions conducted an average of 5 days apart. Effects of age, sex, weight, and wither height on MNT values were assessed separately for each site. Tolerance of horses to the procedure was graded subjectively and correlated with MNT values. Synovitis and osteoarthritis were induced arthroscopically in the middle carpal joint of 1 randomly selected thoracic limb. The opposite limb served as a sham-operated control limb. Mechanical nociceptive threshold values were recorded weekly and correlated with clinical, radiographic, and necropsy scores measured over 10 weeks. Lower MNT values corresponded with increased pain, whereas higher MNT values indicated reduced pain. Results—A gradual increase in MNT values was detected from proximal-to-distal sites of the thoracic limbs. High MNT values were recorded for geldings and tall horses. In general, tolerance to procedure scores was positively correlated with overall pooled MNT values within each thoracic limb. From 2 to 6 weeks after surgery, the osteoarthritic limb had significantly reduced MNT values within the carpal region. The osteoarthritic limb also had significant changes in clinical examination, radiographic, and necropsy scores, which were poorly correlated with MNT values. Conclusions and Clinical Relevance—Pressure algometry provided objective assessment of nociception of the thoracic limb; however, MNT values were poorly correlated with clinical variables used to assess osteoarthritis.

Objective—To examine mRNA expression of cytokines in synovial fluid (SF) cells from dogs with cranial cruciate ligament (CrCL) rupture and medial patellar luxation (MPL) and determine mRNA expression for 3 joints (affected stifle, unaffected contralateral stifle, and left shoulder joints) in dogs with unilateral CrCL rupture. Sample Population—29 stifle joints with CrCL rupture (29 dogs), 8 stifle joints with MPL (7 dogs), and 24 normal stifle joints (16 clinically normal dogs). Procedures—Immediately before reconstructive surgery, SF was aspirated from the cruciate-deficient stifle joint or stifle joint with MPL. Fourteen of 29 dogs had unilateral CrCL rupture; SF was also aspirated from the unaffected contralateral stifle joint and left shoulder joint. Those 14 dogs were examined 6 and 12 months after reconstructive surgery. Total RNA was extracted from SF cells and reverse transcription–PCR assay was performed to obtain cDNA. Canine-specific cytokine mRNA expression was determined by use of a real-time PCR assay. Results—Interleukin (IL)-8 and -10 and interferon-G expression differed significantly between dogs with arthropathies and dogs with normal stifle joints. For the 14 dogs with unilateral CrCL rupture, a significant difference was found for IL-8 expression. Before reconstructive surgery, IL-8 expression differed significantly between the affected stifle joint and left shoulder joint or contralateral stifle joint. Six months after surgery, IL-8 expression was significantly increased in the unaffected contralateral stifle joint, compared with the shoulder joint. Conclusions and Clinical Relevance—No conclusions can be made regarding the role of the examined cytokines in initiation of CrCL disease.

Objective—To investigate the effects of polysulfated glycosaminoglycan (PSGAG) treatment on serum cartilage oligomeric matrix protein (COMP) concentration, matrix metal-loproteinase-2 (MMP-2) and -9 (MMP-9) activities, C-reactive protein (CRP) concentration, and lameness scores in dogs with osteoarthritis. Animals—16 dogs with osteoarthritis and 5 clinically normal dogs. Procedures—Dogs with osteoarthritis had a history of chronic lameness, and osteophytes were observed on radiographic evaluation of the affected joint. Polysulfated glycosaminoglycan was administered IM twice a week for a total of 8 treatments to all dogs with osteoarthritis and to clinically normal control dogs. Results—Lameness scores after PSGAG treatment in osteoarthritic dogs improved in 12 of the 16 dogs. Serum COMP concentrations in osteoarthritic dogs were significantly higher than in control dogs before treatment. Lameness scores in osteoarthritic dogs decreased significantly after treatment, compared with before treatment. Lameness scores of 9 dogs with hind limb lameness improved significantly after treatment; these dogs had corresponding decreases in serum COMP concentrations. After treatment, serum COMP concentrations and lameness scores of 7 dogs with forelimb lameness remained high and were significantly higher than those of dogs with hind limb lameness. Serum MMP-9 activities of dogs with forelimb lameness were significantly higher than in dogs with hind limb lameness after treatment. Conclusions and Clinical Relevance—IM administration of PSGAG inhibited COMP degradation in dogs with osteoarthritis. Results indicate that decreases in serum COMP concentrations might be related to improvement in lameness after PSGAG treatment.

Objective—To detect changes in joint kinematics of clinically sound dogs with or without radiographically detectable borderline hip dysplasia (HD). Animals—20 Belgian Shepherd Dogs (Malinois; mean ± SD age, 2.75 ± 1.32 years) with no clinical signs of HD. Procedures—Kinematic gait analysis was performed in Malinois walking on a treadmill. On the basis of results of radiographic examination for HD and in accordance with guidelines established by the Fédération Cynologique Internationale, dogs were assigned to group 1 (no radiographic signs of HD; 8 dogs) or group 2 (borderline HD; 12 dogs). Ground reaction forces and weight distribution among limbs and differences between groups were evaluated. Maximal sagittal angle during the stance and swing phases, the time at which they were detected, and angle velocities were calculated for joints of the hind limbs. Results—Ground reaction forces revealed no differences between groups. Dogs in group 1 had significant changes (earlier time for maximal flexion of the hip joint and less flexion and less range of motion of the stifle joint), compared with results for dogs in group 2. Maximal angle velocity of the stifle and tarsal joints was significantly lower during the swing phase in group 1 than in group 2. Conclusions and Clinical Relevance—This study revealed that dogs with borderline HD had altered joint kinematics. Our data provide basic kinematic values for clinically sound and affected dogs and can be used to investigate the long-term effects for subclinical radiographic changes of the hip joints of dogs.

OBJECTIVE To develop a model of hip joint synovitis on the basis of intra-articular injection of a sodium urate suspension in dogs and to characterize associated gait changes. ANIMALS 6 healthy adult dogs. PROCEDURES Each dog was sedated, and synovitis was induced by injection of 1 mL of a sodium urate suspension (20 mg/mL) into the right hip joint under ultrasonographic guidance. Observational and instrumented gait analyses to determine temporospatial, kinetic, and kinematic variables were performed prior to and 4, 8, and 24 hours after sedation and synovitis induction. RESULTS Injection of a sodium urate suspension into the hip joint of healthy dogs resulted in lameness of the ipsilateral pelvic limb as determined by observational and instrumented gait analyses. For all dogs, lameness was clinically detectable within 1.5 to 2 hours after injection, reached its maximum intensity at 4 hours after injection, and had subsided by 24 hours after injection. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that injection of a sodium urate suspension into the hip joint of healthy dogs reliably induced synovitis and signs of pain and lameness in the ipsilateral pelvic limb that lasted 24 hours. This model can be used in conjunction with instrumented gait analysis to provide information on gait changes associated with hip joint disease and might be useful for evaluating the efficacy of analgesics or other interventions for the treatment of hip joint disease in dogs.

OBJECTIVE To compare serum concentrations of biomarkers of cartilage and bone metabolism between racehorses with a carpal or metacarpophalangeal or metatarsophalangeal (ie, fetlock) joint injury and matched uninjured control horses, determine changes in biomarker concentrations following joint injury, and establish the biomarkers’ diagnostic test performance. ANIMALS 50 Thoroughbred racehorses with a carpal or fetlock joint injury and 50 matched uninjured horses (control horses). PROCEDURES Serum concentrations of 2 cartilage synthesis biomarkers (carboxy-terminal propeptide of type II collagen [CPII] and chondroitin sulfate epitope 846 [CS846]), 2 cartilage degradation biomarkers (neoepitope generated by collagenase cleavage of type II collagen [C2C] and cross-linked carboxy-terminal telopeptide fragments of type II collagen [CTX-II]), and serum activity of a bone formation marker (bone-specific alkaline phosphatase [BAP]) were measured around the time of injury diagnosis and monthly thereafter for as long as possible. RESULTS Injured horses as a group and horses specifically with fetlock joint injuries had significantly lower serum CPII concentrations and significantly higher serum BAP activities than matched control horses. Concentrations of CTX-II were decreased between 2 and 4 months following joint injury. Measurement of CPII concentration at baseline could distinguish between injured horses and control horses with a sensitivity of 82% and specificity of 50%. CONCLUSIONS AND CLINICAL RELEVANCE Although significant differences in specific biomarker concentrations between horses with carpal and fetlock joint injuries and matched control horses were identified, there was no convincing evidence of the suitability of these biomarkers as diagnostic or prognostic tools in a clinical setting.

Objective—To compare ground reaction forces (GRFs) measured by use of a pressure-sensitive walk-way (PSW) and a force plate (FP) and evaluate weekly variation in the GRFs and static vertical forces in dogs. Animals—34 clinically normal dogs and 5 research dogs with lameness. Procedure—GRF data were collected from 5 lame and 14 clinically normal dogs by use of an FP and a PSW. Peak vertical force (PVF), vertical impulse (VI), and velocity measurements (determined by use of photocells and PSW data) were compared between groups. Peak vertical force, VI, stride length, ground phase time (ie, contact time), and static body weight distribution data were collected on 2 occasions, 1 week apart, in 20 different clinically normal dogs by use of a PSW; week-to-week variation in values was evaluated. Results—Measurements of velocity derived by use of the photocells were not different from those derived by use of the PSW. For any 1 limb, values derived by use of the PSW were significantly lower than values derived with the FP. For values obtained by use of either technique, there were no differences between left and right limbs except for values of PVF measured via PSW in forelimbs. Values of PVF, VI, contact time, stride length, and static weight distribution generated by the PSW did not vary from week to week. Conclusions and Clinical Relevance—Values for GRFs varied between the FP and PSW. However, data derived by use of PSW were consistent and could be used to evaluate kinetic variables over time in the same dog.

Objective—To evaluate the association between subjective lameness grades and kinetic gait parameters and assess the variability in kinetic parameters in horses with experimentally induced forelimb lameness.Animals—32 horses.Procedures—Forelimb lameness was induced in each horse via injection of lipopolysaccharide into 1 metacarpophalangeal joint (40 experimental trials). Subjective lameness grading and 13 kinetic gait parameters (force plate analysis) were assessed before (baseline) and at 12, 18, and 24 hours after lipopolysaccharide injection. While horses were trotting, kinetic gait analysis was performed for 8 valid repetitions at each time point. Repeated-measures analyses were performed with 8 repetitions for each kinetic parameter as the outcome, and lameness grades, time points after lipopolysaccharide injection, and repetition order as explanatory variables. Sensitivity and specificity of kinetic parameters for classification of horses as sound or lame (in relation to subjective lameness scores) were calculated. Between- and within-horse variabilities of the 13 kinetic parameters were assessed by calculation of coefficients of variation.Results—Subjective lameness grades were significantly associated with most of the kinetic parameters. Vertical force peak and impulse had the lowest between- and within-horse coefficients of variation and the highest correlations with subjective lameness grade. Vertical force peak had the highest sensitivity and specificity for lameness classification. Vertical force peak and impulse were significantly decreased even in horses with mild or unobservable lameness.Conclusions and Clinical Relevance—Among the kinetic gait parameters, vertical force peak and impulse had the best potential to reflect lameness severity and identify subclinical forelimb gait abnormalities. (Am J Vet Res2005;66:1805–1815)

Objective—To determine whether iatrogenic hemarthrosis of the metacarpophalangeal joint could be used as a model for temporary reversible joint pain in horses. Animals—8 adult horses. Procedure—Each horse was evaluated on a treadmill before and after injection of 1 metacarpophalangeal joint with 10 mL of autogenous blood. Horses were evaluated subjectively and objectively by use of a computerized force measurement system at intervals until lameness abated. The mean force difference between injected and noninjected limbs at all time periods after injection was compared with the difference between limbs at baseline. From each horse, synovial fluid samples collected before and 24 hours and 30 days after injection were analyzed for total protein concentration and cell type and number. Venous blood samples were collected before and 6 and 24 hours after injection for assessment of plasma cortisol concentration. Results—For 24 hours after injection, the mean force difference between injected and noninjected limbs was significantly increased over baseline. The greatest force difference was detected after 2 and 4 hours. Baseline and 24-hour force data were not significantly different. Compared with baseline values, synovial fluid protein concentration and nucleated cell and RBC counts were increased significantly at 24 hours after injection but were not different at 30 days after injection. No significant changes in plasma cortisol concentration were detected at any time point. Conclusions and Clinical Relevance—In horses, iatrogenic hemarthrosis of the metacarpophalangeal joint appears to induce temporary reversible lameness with a mild to moderate degree of synovitis. (Am J Vet Res 2005;66:1084–1089)

Objective—To define relationships between hoofacceleration patterns of galloping horses and dynamic properties of the track. Animals—8 Thoroughbred horses without lameness. Procedure—Acceleration-time curves were recorded by use of accelerometers attached to each hoof as each horse galloped over the track straightaway. Four sessions were conducted for each horse, with the track surface modified by sequentially adding water before each session. These acceleration-time curves were analyzed to determine peak accelerations during the support phase of the stride. Track dynamic properties (hardness, rebound, deceleration rate, rebound rate, and penetration) were recorded with a track-testing device. Moisture content and dry density were measured from soil samples. Stepwise multiple regression was used to identify relationships between hoof-acceleration variables and track dynamic properties. Results—Track rebound rate was most consistently related to hoof variables, especially through an inverse relationship with negative acceleration peaks for all hooves. Also, rebound rate was related to initial acceleration peak during propulsion of the hooves of the forelimb and the nonlead hind limb as well as to the second acceleration peak during propulsion of the lead hooves of the hind limb and nonlead forelimb. Conclusions and Clinical Relevance—The inverse relationship between track rebound rate and negative acceleration peaks for all hooves reflects the most important dynamic property of a track. Any factor that reduces negative acceleration of the hooves will increase stride efficiency by allowing smoother transition from retardation to propulsion and therefore may be important in determining the safety of racing surfaces. (Am J Vet Res 2005;66:589–595)

Objective—To develop a visual analogue scale (VAS) questionnaire that is repeatable and valid for use in assessing pain and lameness in dogs. Sample Population—48 client-owned dogs with mild to moderate lameness. Procedure—The dogs were from 3 studies conducted during a 3-year period. Of the 48 dogs, 19 were used in repeatability assessment, 48 were used in principal component analysis, and 44 were used in model selection procedures and validity testing. A test-retest measure of repeatability was conducted on dogs with a change of < 10% in vertical peak force. A force platform was used as the criterion-referenced standard for detecting lameness. Principal component analysis was used to describe dimensionality of the data. Repeatable questions were used as explanatory variables in multiple regression models to predict force plate measurements. Peak vertical, craniocaudal, and associated impulses were the forces used to quantify lameness. The regression models were used to test the criterion validity of the questionnaire. Results—19 of 39 questions were found to be repeatable on the basis of a Spearman rank-correlation cut point of > 0.6. Model selection procedures resulted in 3 overlapping subsets of questions that were considered valid representations of the forces measured (vertical peak, vertical impulse, and propulsion peak). Each reduced model fit the data as well as the full model. Conclusions and Clinical Relevance—The VAS questionnaire was repeatable and valid for use in assessing the degree of mild to moderate lameness in dogs. (Am J Vet Res 2004;65:1634–1643)