Influence of Wearing a Tactical Harness on Three-Dimensional Thoracic Limb Kinematics.

OBJECTIVE: The aim of this study was to assess the impact of a tactical harness on three-dimensional motion of the thoracic limb in dogs. ANIMALS: Five adult mixed-breed dogs (age: 4-6 years, weight: 25-35 kg) were used in this study. METHODS: Custom-fit tactical harnesses were applied to each dog and 19 retroreflective skin markers were used to determine three-dimensional joint motion during dynamic motion, with and without the harness. Sagittal plane (flexion-extension), transverse plane (internal-external rotation), and frontal plane (abduction-adduction) kinematics were created for the shoulder, elbow, and carpus from motion capture data, with and without the harness. Kinematic waveforms were analysed using statistical parametric mapping paired t-tests (a = 0.05). Angular displacements were determined, and total joint range of motion was compared using paired t-tests (a = 0.05). RESULTS: Wearing a tactical harness increased sagittal angular displacement in the elbow but decreased it in the shoulder and carpus. Significant differences were found in the kinematic waveforms in almost all joints at both a walk and trot. Dogs wearing the tactical harness had reduced flexion and increased abduction of the shoulder joint at a walk. The elbow joint had increased extension, reduced external rotation and increased abduction at both walk and trot. The carpus had reduced flexion at a trot and walk, as well as increased internal rotation and abduction at a walk. CONCLUSION: Wearing a tactical harness affected kinematic gait data of all joints of the forelimb. The elbow was affected in all three planes at both a walk and trot, while the shoulder joint was only affected at a walk when wearing a tactical harness. CLINICAL RELEVANCE: The clinical impact of wearing a tactical harness is unknown at this time, particularly when dogs are performing their duties while wearing harnesses.

Comparison of Canine Forelimb Kinematic Joint Angles Collected with 2D and 3D Models.

OBJECTIVE: The aim of this study was to compare a Joint Coordinate System (JCS) three-dimensional (3D) kinematic model of the canine forelimb with more widely used linear (LIN) and segmental (SEG) 2D models. STUDY DESIGN: It was an in vivo biomechanical study. ANIMALS: Normal adult mixed breed dogs were used in this study (n = 6). METHODS: Nineteen retroreflective markers were applied to the skin of dogs' right forelimbs. Dogs were trotted and walked through the calibrated testing space. The first five good trials were used to generate sagittal plane (flexion and extension angle) waveforms from 3 different models (JCS, LIN and SEG) for the shoulder, elbow and carpal joints. The JCS model also generated transverse and frontal plane joint angular data (internal/external and abduction/adduction angles) for all three joints. Minimum, maximum and total angular displacement was calculated for each joint. Comparison of sagittal plane waveforms was performed before and after waveform alignment using statistical parametric mapping. RESULTS: Each model produced similar sagittal plane waveforms, though the LIN model had a greater vertical shift along the y-axis for the shoulder and elbow. Before waveform alignment, differences were revealed between the LIN model when compared to JCS or SEG model at a trot. No differences were revealed at a walk. After waveform alignment, no differences were revealed between models at a walk or trot. There were no differences in angular displacement measurements between models before or after waveform alignment at a walk or trot. CONCLUSIONS: The 3D JCS model reported in this study produced sagittal plane waveforms comparable to conventional 2D models while also providing joint specific information from other planes of motion.

Application of a Joint Coordinate System Kinematic Model to the Canine Thoracic Limb.

OBJECTIVE: The aim of this study was to apply a three-dimensional kinematic model to the canine thoracic limb using a joint coordinate system. ANIMALS: Six clinically normal adult mixed-breed dogs. PROCEDURES: Dogs had 19 retroreflective markers affixed to the skin of the right forelimb. Twelve infrared cameras were arranged in a circle around the testing space, recording the locations of the markers as dogs walked and trotted through the testing space. Five trials were used of both walks and trots at velocities 0.9 to 1.2 m/s and 1.7 to 2.1 m/s respectively. Raw marker location data were used to generate a joint coordinate system, and a six degrees of freedom model of the canine forelimb was created. Three-dimensional kinematic angles were collected for the shoulder, elbow and carpal joints. RESULTS: Sagittal, transverse and frontal plane kinematics joint angles were generated by use of a joint coordinate system. Range of motion was calculated for each joint in all three planes. CONCLUSION AND CLINICAL RELEVANCE: This minimally invasive joint coordinate system model can be used in both clinical and research settings to determine changes in range of motion of the shoulder, elbow or carpus in the canine forelimb in three dimensions.

Efficacy of postoperative antibiotic use after tibial plateau leveling osteotomy in dogs: A systematic review.

OBJECTIVE: A systematic review of published data to determine whether postoperative antibiotic use after tibial plateau leveling osteotomy (TPLO) decreases infection rates. STUDY DESIGN: Systematic review. METHODS: A broad bibliographic search was performed in three online databases through March 2020 for publications on postoperative antibiotic use after TPLO in dogs. Search terms included dog, canine, TPLO, tibial plateau leveling osteotomy, infection, antibiotic, and antimicrobial. Articles that met inclusion criteria were evaluated for level of evidence (LoE) by a modified Oxford Level of Evidence (mOLE) and GRADE (Grading of Recommendations, Assessment, Development and Evaluation) classification and evaluation. RESULTS: Thirteen studies met the inclusion criteria. Effect of antibiotic use was the primary question in four studies. Among those, 50% (2/4) were assigned a mOLE of 1b and a GRADE of moderate, while the other 50% (2/4) were assigned a mOLE of 4b or 4c with a GRADE of low. The two studies with the highest LoE did not provide evidence of the benefit of antibiotic usage. Results of only one study provided evidence to support the use of postoperative antibiotics. The remaining nine studies provided evaluation of antibiotic use secondarily and were all assigned a low LoE. Among these, 78% (7/9) provided evidence to support the use of postoperative antibiotics. CONCLUSION: We found little evidence to support the use of postoperative antibiotics to reduce the risk of surgical site infections in dogs after TPLO. The answer to this clinical question is complicated by the lack of prospective studies and inconsistent treatment protocols in the evaluated studies. CLINICAL SIGNIFICANCE: The clinical impact of postoperative antibiotic administration on infection rates after TPLO is uncertain.

Evaluation of Ground Reaction Forces and Limb Symmetry Indices Using Ground Reaction Forces Collected with One or Two Plates in Dogs Exhibiting a Stifle Lameness.

OBJECTIVE: The aim of the study was to evaluate the efficiency and consistency in the collection of ground reaction forces using one or two force plates from dogs with stifle lameness. ANIMALS: Twenty-two client-owned dogs with unilateral stifle lameness were used. METHODS: In a prospective study design, data were collected at a single time point using both one- and two-plate collection methods. Ground reaction forces collected included peak vertical force, vertical impulse and associated symmetry indices. Additionally, time required to obtain valid trials and the total number of trials were also recorded for both one-plate and two-plate collections. Linear mixed models were used to analyse differences in peak vertical force, vertical impulse and symmetry indices between the collection methods. A paired-T test was used to compare trial number and time of trial collection. The significance threshold was p < 0.05. RESULTS: It took significantly longer to collect valid trials using one-plate both in time (16.1 ± 8.0 minutes vs, 8.0 ± 4.3 minutes with two plates) and number of trials (33.8 ± 14.8 trials vs. 16.4 ± 8.8 trials with two plates) (p < 0.0001). There was no difference in peak vertical force or vertical impulse data between collection methods. Neither the peak vertical force symmetry indices nor the vertical impulse symmetry indices were significantly different between one- and two-plate collection techniques. CONCLUSION: The total time and number of trials needed to collect valid trials in dogs with stifle lameness were minimized through the use of two force plates. However, there was no significant difference in the ground reaction force or symmetry index values collected between the two systems.

Review of kinematic analysis in dogs.

Objective gait analysis techniques aid investigators in the study of motion. Kinematic gait analysis techniques that objectively quantitate motion are valuable tools used to understand normal and abnormal motion in domestic animals. Recent advances in video technology have made the study of motion more readily accessible. Available systems can document gait in two or three dimensions (2D or 3D, respectively). Knowledge of fundamental gait analysis concepts is critical to generating meaningful data. The objective of this report is to review principles of kinematic data collection and analyses, with a focus on differences between 2D and 3D systems.

Comparison of the effects on lameness of orally administered acetaminophen-codeine and carprofen in dogs with experimentally induced synovitis.

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.

Resistin concentrations in serum and stifle synovial fluid from normal and cruciate deficient dogs with osteoarthritis.

OBJECTIVE: To compare synovial fluid (SF) resistin concentrations in healthy dogs to dogs with osteoarthritis (OA) secondary to cranial cruciate ligament (CrCL) injury and to correlate resistin concentrations with body condition score (BCS) and evaluate resistin release from peripheral blood mononuclear cells (PBMC) and adipocytes. STUDY DESIGN: Controlled, prospective, clinical study ANIMALS: Thirty-nine client-owned dogs, 13 healthy and 26 with secondary OA, were enrolled. Blood was collected from six healthy purpose-bred dogs for PBMC culture. An additional six mixed-breed dogs were used for adipocyte collection and culture. METHODS: Resistin concentrations were measured with a canine-specific enzyme-linked immunoabsorbent assay. Resistin was compared between healthy SF and OA SF with Student's t test. Correlation of resistin concentrations to BCS was performed. Peripheral blood mononuclear cells and adipocytes were cultured under three conditions: negative control, lipopolysaccharide, and concanavalin A (Con A). A linear mixed model was used to determine differences in resistin concentrations among treatments. RESULTS: Resistin concentrations in OA SF were comparable to healthy SF. Neither serum nor SF resistin was correlated with BCS. Cultured PBMC stimulated with Con A released resistin, while adipocytes did not. CONCLUSION: Neither serum nor SF resistin were altered in dogs with OA secondary to CrCL insufficiency. In addition, resistin was not correlated with canine body fat and did not appear to function as adipocytokine in the dog. CLINICAL SIGNIFICANCE: Resistin may not be involved in the pathogenesis of OA. However, resistin may be important in inflammation because it is released from inflammatory cells.

Impact of wearing a service vest on three-dimensional truncal motion in dogs.

OBJECTIVE: To develop a 3-D kinematic model to measure truncal motion in dogs and assess changes in truncal motion in dogs when wearing each of 2 service vests. ANIMALS: 5 adult mixed-breed dogs. PROCEDURES: 27 reflective markers were placed on the pelvis, trunk, and scapula of each dog. Six infrared cameras were placed around a treadmill to track the location of the markers within a calibrated space. Dogs were recorded during walking and trotting on the treadmill. Local and global coordinate systems were established, and a segmental rigid-body model of the trunk was created. Dogs were then recorded while wearing a custom vest and an adjustable vest during walking and trotting on the treadmill. Range of motion of the trunk when dogs were and were not wearing vests was compared by repeated-measures ANOVA. RESULTS: An anatomic coordinate system was established by use of markers located at T1, T13, and the xiphoid process. Range of motion of the trunk during a gait cycle did not differ significantly regardless of the day of the test for both walking and trotting gaits. Trunk motion of dogs when walking and trotting was significantly reduced when dogs were wearing a vest, compared with trunk motion when not wearing a vest. CONCLUSIONS AND CLINICAL RELEVANCE: A 3-D kinematic model for measuring truncal rotation was developed. Results indicated measurable differences in the gait of dogs when wearing each of the 2 service vests, compared with the gait when not wearing a vest.

Elevated Synovial Fluid Concentration of Monocyte Chemoattractant Protein-1 and Interleukin-8 in Dogs with Osteoarthritis of the Stifle.

Chemokines such as monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8) have been shown to cause monocyte and natural killer cell chemotaxis and polymorphonuclear cell chemotaxis, respectively. Additionally, MCP-1 signalling has been implicated in modulating pain. Elevated synovial fluid concentrations of MCP-1 and IL-8 have been demonstrated in humans with osteoarthritis, but currently there are no studies evaluating synovial MCP-1 or IL-8 concentrations in dogs. Additionally, there are no canine studies evaluating the correlation between these chemokines and caregiver perceived pain and mobility, as measured by the clinical metrology instrument, Liverpool Osteoarthritis in Dogs. This study documented elevated synovial fluid concentrations of IL-8 and MCP-1 in the stifle of dogs with secondary osteoarthritis compared with normal stifles. However, this study found no correlation between MCP-1 or IL-8 and Liverpool Osteoarthritis in Dogs or radiographic severity of osteoarthritis.

Comparison of two inhibitors of E-type prostanoid receptor four and carprofen in dogs with experimentally induced acute synovitis.

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.

Correlation of serum and synovial leptin concentrations with body condition scores in healthy and osteoarthritic dogs.

OBJECTIVE: To evaluate the relationship between serum and synovial fluid (SF) leptin concentrations and body condition score (BCS) in healthy and osteoarthritic dogs. STUDY DESIGN: Controlled, prospective, clinical study. ANIMALS: Nineteen healthy dogs and 29 dogs with osteoarthritis (OA) secondary to cranial cruciate ligament injury. METHODS: Synovial fluid was obtained from the femorotibial joint under sedation (healthy dogs) or during surgery (OA dogs). Serum and SF leptin and interleukin (IL)-1ß concentrations were measured via enzyme-linked immunosorbent assay. Dogs were classified as optimal weight (BCS 4-5/9) or overweight (BCS >5/9). Radiographs were scored for OA severity by a radiologist. Owners completed the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire. RESULTS: Mean (± SD) SF leptin (4.09 ± 4 ng/mL) was lower than serum leptin (6.88 ± 5.52 ng/mL, P < .0001). Synovial fluid leptin was higher in overweight (5.28 ± 4.21) than in optimal body weight dogs (1.54 ± 1.72 ng/mL, P < .0001). Serum (P < .001) and SF leptin (P = .004) concentrations were associated with BCS. Concentration of SF leptin did not differ between healthy (2.4 ± 2.04 ng/mL) and OA (4.9 ± 4.3 ng/mL, P = .25) dogs. Synovial fluid leptin and LOAD scores were weakly associated (P = .03). No association was detected between SF leptin and radiographic score or IL-1ß (P = .73). CONCLUSION: Serum and SF leptin correlated with BCS in this population. Synovial fluid leptin was weakly associated with LOAD scores but not with radiographic severity of OA or IL-1ß. CLINICAL SIGNIFICANCE: Serum and SF leptin concentrations do not predict radiographic severity of canine OA but contribute to joint pain and dysfunction.

Lack of effectiveness of tramadol hydrochloride for the treatment of pain and joint dysfunction in dogs with chronic osteoarthritis.

OBJECTIVE To investigate the effectiveness of tramadol for treatment of osteoarthritis in dogs. DESIGN Randomized, blinded, placebo-controlled crossover study. ANIMALS 40 dogs with clinical osteoarthritis of the elbow or stifle joint. PROCEDURES Dogs orally received 3 times/d (morning, midday, and night) for a 10-day period each of 3 identically appearing treatments (placebo; carprofen at 2.2 mg/kg [1 mg/lb], q 12 h [morning and night], with placebo at midday; or tramadol hydrochloride at 5 mg/kg [2.3 mg/lb], q 8 h) in random order, with treatment sessions separated by a minimum 7-day washout period. Vertical ground reaction forces (vertical impulse [VI] and peak vertical force [PVF]) were measured and Canine Brief Pain Inventory (CBPI) scores assigned prior to (baseline) and at the end of each treatment period. Repeated-measures ANOVA was performed to compare VI and PVF data among and within treatments, and the χ2 test was used to compare proportions of dogs with a CBPI-defined positive response to treatment. RESULTS 35 dogs completed the study. No significant changes from baseline in VI and PVF were identified for placebo and tramadol treatments; however, these values increased significantly with carprofen treatment. Changes from baseline in VI and PVF values were significantly greater with carprofen versus placebo or tramadol treatment. A significant improvement from baseline in CBPI scores was identified with carprofen treatment but not placebo or tramadol treatment. CONCLUSIONS AND CLINICAL RELEVANCE 10 days of treatment with tramadol as administered (5 mg/kg, PO, q 8 h) provided no clinical benefit for dogs with osteoarthritis of the elbow or stifle joint.

Effect of Limb Position at the Time of Skin Marker Application on Sagittal Plane Kinematics of the Dog.

Objectives To evaluate the effect of limb position during initial skin marker application on sagittal plane kinematics of the hindlimb. Methods Six healthy dogs (20-30 kg) were evaluated. An established two-dimensional kinematic model of the pelvic limb was utilized to describe sagittal plane motion. Kinematic markers were applied separately for each dog while standing in three different positions: (1) the limb extended cranially, (2) a normal standing limb position and (3) the limb extended caudally. Following marker application at each of the three positions, dynamic gait was recorded at a walk (velocity, 0.9-1.2 m/s; acceleration, 0.5m/s2). Five valid trials were used for comparison. Complete waveform analysis was performed with generalized indicator function analysis (GIFA). Maximum and minimum joint angles and joint range of motion were compared with a one-way repeated measures ANOVA with significance at p < 0.05. Results Significant differences were found between stifle waveforms. No differences were found between the hip or tarsus waveforms. Minimum and maximum joint angles were significantly different for the hip and stifle but not for the tarsus. No differences were found between ranges of motion for any joint evaluated. Clinical Significance Limb position at the time of skin marker application affects gait data and is an important consideration for kinematic analysis of the hindlimb in dogs.

Synovial membrane receptors as therapeutic targets: A review of receptor localization, structure, and function.

Joint pathology and degeneration is a significant cause of pain. The synovial membrane plays an important role in maintenance of the joint, contributes to the pathology of many arthropathies and may be adversely affected in joint disease. Improving knowledge of the receptors present within the synovium will aid in a better understanding of joint pathology and the development of new treatments for diseases such as osteoarthritis and rheumatoid arthritis. Knowledge of the location and function of synovial membrane receptors (both in healthy and diseased synovium) may provide important targets in the treatment of various arthropathies. Classic pain receptors such as opioid receptors in the synovium are a mainstay in local and systemic management of chronic pain in many species. In addition to these, many other receptors such as bradykinin, neurokinin, transient receptor potential vanilloid, and inflammatory receptors, such as prostanoid and interleukin receptors have been discovered within the synovial membrane. These receptors are important in pain, inflammation, and in maintenance of normal joint function and may serve as targets for pharmacologic intervention in pathologic states. The goal of this review is to outline synovial membrane receptor localization and local therapeutic modulation of these receptors, in order to stimulate further research into pharmacological management of arthropathies at the local level. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1589-1605, 2017.

Pelvic limb kinematics in the dog with and without a stifle orthosis.

OBJECTIVE: To report a method of evaluating 3-dimensional joint motion in dogs with a stifle orthosis. STUDY DESIGN: Experimental. ANIMALS: Six healthy dogs. METHODS: Three-dimensional pelvic limb joint motion was recorded with and without a stifle orthosis. Kinematic data were collected from dogs at a walk and trot for the hip, stifle, and tarsus prior to, and after application of, a stifle orthosis. Data were also obtained for the orthosis alone. Comparisons were made between the braced and unbraced limb, and between the braced limb and the orthosis alone. Complete waveforms, kinematic, and temporospatial variables were compared. RESULTS: Gait waveforms differed between braced and unbraced limbs for all joints and planes of motion (P < .05), as well as between the braced stifles and the orthosis alone at both a walk and trot. However, joint ROM was inconsistently altered. The effect of bracing on stifle ROM was limited to a reduced extension at the end of stance. Adjacent joint ROM was affected by the stifle orthosis. Temporospatial variables were predominantly affected while walking. CONCLUSIONS: The restrictive motion of the stifle orthosis is not fully translated to the underlying joint, based on the limited differences between the motion of braced and unbraced stifles. This effect varies with plane of motion and phase of the gait cycle, with most changes in stifle motion being detected during the stance phase. The stifle orthosis had an equal or greater effect on the motion of adjacent joints, especially the tarsus.

The evaluation of limb symmetry indices using ground reaction forces collected with one or two force plates in healthy dogs.

OBJECTIVE: To compare the variability of symmetry indices within and between days when using one and two force plates for data collection. ANIMALS: Seventeen healthy client-owned adult dogs. METHODS: Vertical ground reaction force data were collected in a crossover study design, with four collection sessions on two consecutive days, and then two weeks apart (days 1, 2, 15, and 16) using both 1-plate and 2-plate collection methods. Symmetry indices were calculated for limb pairs using two standard equations (SI1 and SI2). Repeated measures analysis was used to compare symmetry indices data between plate systems and days. Significance was set at p <0.05. RESULTS: There were no significant differences between plate systems for SI1 and SI2. There were no significant differences between data collected on different days and no significant interaction effects between variables. Symmetry indices were consistently larger for ground reaction forces calculated from non-consecutive footfalls. CONCLUSIONS: The use of two force plate systems will minimize variance caused by trial repetition and paired limb variation. When comparing SI1 to SI2, results were not significantly different. However, there were consistently higher mean values for SI1 compared with SI2 and symmetry indices were consistently larger for 1-plate systems compared to 2-plate systems for both symmetry indices.

Comparison of NIRS, serum biomarkers, and muscle damage in a porcine balloon compression model of acute compartment syndrome.

BACKGROUND: Near-infrared spectroscopy (NIRS) has been shown to aid in the diagnosis of extremity acute compartment syndrome (ACS), offering continuous real-time capability to monitor perfusion in extremities. Porcine models of ACS have been developed to attempt to aid in the understanding of the development of ACS and provide better methods of diagnosing ACS. The objective of the present study was to assess and correlate NIRS, tibial intracompartmental pressure (TICP), tibial intracompartmental perfusion pressure (TIPP), serum markers of inflammation and muscle injury in a balloon compression model of ACS. METHODS: Six swine were used. Balloon catheters were inflated below the cranial tibial muscle. Systolic, diastolic, and mean arterial pressures; compartmental pressures; and oximetry were measured before, during, and after balloon inflation/deflation. Cranial tibial muscle was collected for muscle damage scoring. Serum creatine kinase, myoglobin, tumor necrosis factor α, IL-1ß, and IL-6 were measured. Data analysis included comparing differences in TICP, NIRS, and TIPP measurements as well as creatine kinase, myoglobin, tumor necrosis factor α, IL-1ß, and IL-6 levels between time points. Pearson correlations were calculated for muscle degeneration and edema and NIRS. RESULTS: Increases in TICP and decreases in TIPP were found. Near-infrared spectroscopy detected significant changes in tissue oxygenation at all the same time points. Myoglobin significantly increased from 45.7 ± 13.0 ng/mL (baseline) to 219.5 ± 57.3-ng/mL (balloon deflation) and continued to increase over the duration of the study. Creatine kinase significantly increased 2 hours after balloon deflation. Cranial tibial muscle degeneration, necrosis, and edema scores were higher in the test than the control legs. CONCLUSIONS: Near-infrared spectroscopy of the compartment provided a reliable, sensitive measure of both an increase and decrease in TICP and TIPP in this porcine balloon model of ACS. Creatine kinase and myoglobin significantly increased following balloon removal. Significant correlations between muscle degeneration, edema, hemorrhage, and NIRS were found.

Elevated synovial fluid concentration of adenosine triphosphate in dogs with osteoarthritis or sodium urate-induced synovitis of the stifle.

Adenosine triphosphate has been shown to stimulate nociceptive nerve terminals in joints. Elevated synovial fluid adenosine triphosphate concentrations as well as a correlation between synovial fluid adenosine triphosphate concentrations and osteoarthritic knee pain has been demonstrated in humans, but not yet in dogs. This study documented elevated synovial fluid adenosine triphosphate concentrations in the stifles of dogs with secondary osteoarthritis and urate-induced synovitis, as compared to normal stifles.