Distribution of vertical forces in the pads of Greyhounds and Labrador Retrievers during walking

OBJECTIVE: To document peak vertical force (PVF) and vertical impulse (VI) in the pads of Greyhounds and Labrador Retrievers. ANIMALS: 8 Greyhounds and 8 Labrador Retrievers. PROCEDURE: Velocity and acceleration were restricted to ranges of 0.9 to 1.1 m/s and -0.1 to 0.1 m/s2, respectively. The PVF and VI measurements were collected from digital pad (DP)-2, -3, -4, and -5 and the metacarpal pad (McP) or metatarsal pad (MtP) of each limb in each dog. RESULTS: We found no significant differences between the left and right forelimbs or hind limbs for any pad in either breed. Vertical forces in the forelimb were always greater than those in the hind limb. The PVF in the forelimbs of Greyhounds was greatest in DP-3, -4, and -5 and DP-3, DP-4, and the MtP in the hind limbs. The VI in Greyhound forelimbs was greatest in DP-3, -4, and -5 but greatest in DP-4 in the hind limbs. The PVF in the forelimbs of Labrador Retrievers was greatest in the McP, whereas in the hind limbs it was greatest in DP-4. The VI in Labrador Retriever forelimbs was greatest in DP-3, DP-4, and the McP but greatest in DP-3 and -4 in the hind limbs. Significant differences were detected in load distribution between the breeds. CONCLUSIONS AND CLINICAL RELEVANCE: This study confirms that DP-3 and DP-4 are major weight-bearing pads in dogs. However, loads were fairly evenly distributed, and DP-5 and the McP or MtP bear a substantial amount of load in both breeds.     

Effect of hind limb position on the craniocaudal length of the lumbosacral space in anesthetized dogs

Objective To investigate whether rostral extension of the hind limbs increases the cranio‐caudal dorsal interlaminar distance between the seventh lumbar vertebra and the sacral bone (LS distance) in sternally recumbent anesthetized dogs. Study design Prospective clinical study. Animals Eighteen dogs (eight neutered males, three intact males, six spayed females, one intact female) of various breeds, weighing 4–34 kg and ranging in age from 1 to 13 years. Methods Each dog was grouped by size: small (≤10 kg), medium (15–20 kg) or large (≥25 kg). Each dog was anesthetized and positioned in sternal recumbency. Computed tomography (CT) of the lumbosacral area was performed with the hind limbs resting on the stifle and the feet extended posteriorly, and then with the hind limbs extended rostrally. LS distance, craniocaudal dorsal interlaminar distance between sixth and seventh lumbar vertebra (L6–L7 distance), length of L7 vertebral body and lumbosacral angle (LS angle) were measured on a reconstructed mid‐sagittal CT image from the two hind limb positions. The measurements from the two hind limb positions for the whole dog population and by size were compared using Student’s T tests. Diagnostic interpretation of the CT images was performed. Results The length of L7 was taken as the reference value as it was not affected by hind limb position. LS distance, L6–L7 distance and LS angle were significantly higher when the hind limbs were extended rostrally in all three size groups. The CT images of ten dogs showed clinically undetected osteoarthrosis of the ileo‐ and lumbosacral area. Conclusions and clinical relevance Rostral extension of the hind limbs significantly increases LS and L6–L7 distance and LS angle even in dogs with clinically undetected osteoarthrosis of the ileo‐ and lumbosacral area, and may enhance the ease of lumbosacral epidural injection in sternally recumbent anesthetized dogs.     

Temporospatial and kinetic characteristics of sheep walking on a pressure sensing walkway

The walking gait of sheep was analyzed in terms of temporospatial and kinetic parameters and weight distribution among the 4 limbs. Eighteen mature female Suffolk-mix sheep walked comfortably with a halter-guide over a 1.5-m pressure sensing walkway. Six valid trials were acquired for each sheep without any previous selection or habituation. Stance phases of the forelimb and hind limb were 66.3% and 68.9%, respectively, of total gait cycle, and limb velocity was 1.06 m/s in both forelimbs and hind limbs while walking. The mean peak vertical force (PVF) and vertical impulse (VI) as percentage of body weight in the forelimbs were 52.5% and 19.9%, respectively, and those of the hind limbs were 38.5% and 14.9%, respectively. More body weight was loaded on the forelimbs than the hind limbs, at 59% and 41% of body weight, respectively. The walking gait of sheep measured with the pressure sensing (PS) walkway was similar to that reported in dogs and horses. The PS walkway enabled collection of temporospatial and kinetic data, and simplified the process of data collection.     

Limb loading activity of adult horses confined to box stalls in an equine hospital barn

OBJECTIVE: To determine a range of limb loading activity for healthy adult horses confined to box stalls in an equine veterinary teaching hospital and determine the effects of hospital environmental factors on load rates and daily limb loading patterns. ANIMALS: 6 mature healthy horses of various ages, breeds, and sexes, and 1 horse with a repaired metatarsal fracture. PROCEDURE: Step monitors were placed on 2 limbs of adult horses confined to box stalls. Relocation steps and weight shifts were recorded, as loading events, for 24 hours. Influence of forelimb versus hind limb and environmental factors on load rate (loading events per hour) were assessed with repeated-measures ANOVA. RESULTS: Loading activity was greater for the forelimb than the hind limb and was greater during the day than the night. Loading activity differences were not associated with daytime environmental factors. CONCLUSIONS AND CLINICAL RELEVANCE: Horses with normal locomotor activity appear to have higher load rates for forelimbs compared with hind limbs and higher load rates during the day compared with night. Knowledge of influence of environmental factors and mechanical restraint on limb loading activity may be useful in management of horses with musculoskeletal disorders. This information may also be used for in vitro simulation of in vivo loading of limbs during cyclic biomechanical investigations.     

Accuracy of an oscillometric blood pressure monitor during phenylephrine-induced hypertension in dogs

OBJECTIVE: To examine the agreement between direct arterial blood pressure measurements obtained from 2 arteries and indirect blood pressure measurements obtained with an oscillometric blood pressure monitor (OBPM) during normotension and phenylephrine-induced hypertension in dogs. ANIMALS: 16 male Beagles. PROCEDURES: In anesthetized dogs, arterial catheters were placed in the lingual and dorsal pedal arteries for measurement of arterial blood pressure. A blood pressure cuff was placed on either the dog's fore- or hind limb and connected to an OBPM. Systolic, diastolic, and mean arterial blood pressures (SAP, DAP, and MAP, respectively) were recorded from both arteries and the OBPM every 5 minutes for 30 minutes (baseline), during a 30-minute period in which dogs received a phenylephrine infusion IV to induce hypertension, and for 30 minutes after discontinuation of the infusion. Mean differences in blood pressure values and confidence intervals were calculated to compare the indirect and direct measurement techniques. RESULTS: In dogs, oscillometry underestimated SAP during normotension, and the difference between oscillometric and direct measurements increased during hypertension. Oscillometry underestimated DAP, but the difference between oscillometric and direct measurements decreased during hypertension. There was close agreement among techniques for MAP determinations. Biases between direct measurements and OPBM blood pressure values measured from dogs' forelimbs or hind limbs were not significantly different. CONCLUSIONS AND CLINICAL RELEVANCE: In normotensive dogs, oscillometric measurements of MAP and SAP agreed more closely with direct arterial pressure measurements than oscillometric estimates of DAP. Oscillometric measurement of MAP was accurate during both normotension and hypertension in dogs.     

Imaging findings and surgical treatment of hemivertebrae in three dogs

CASE DESCRIPTION: 3 immature screw-tailed dogs were evaluated because of progressive pelvic limb paraparesis. CLINICAL FINDINGS: Each dog had marked ataxia and paresis of the pelvic limbs and a palpable deformity of the midthoracic portion of the vertebral column. Pain perception in the pelvic limbs was considered normal, and there was no evidence of fecal or urinary incontinence in any of the 3 dogs. Radiography and magnetic resonance imaging revealed hemivertebrae with severe dorsoventral stenosis of the vertebral canal resulting in spinal cord compression in 2 dogs and lateral compression in the other. TREATMENT AND OUTCOME: Each dog underwent decompressive surgery consisting of dorsal laminectomy or hemilaminectomy and vertebral stabilization by use of combinations of Kirschner wires or threaded external fixator pins plus polymethylmethacrylate bone cement. All dogs regained strong locomotor function with minimal residual pelvic limb ataxia. CLINICAL RELEVANCE: Little detailed information regarding surgical treatment of hemivertebrae in dogs is available; results of treatment in these 3 dogs suggest that spinal cord decompression and stabilization of the vertebral column can achieve a satisfactory, functional outcome.     

Association between limb conformation and retention of sows through the second parity

OBJECTIVE: To determine the association between limb conformation scores in gilts and retention through the second parity. ANIMALS: 961 gilts. PROCEDURE: Gilts were monitored for 1 year. Baseline data recorded were conformation scores for the forelimbs and hind limbs and backfat thickness. Primary outcome was time to removal from a herd, and the secondary outcome was time to removal as a result of lameness. RESULTS: 662 of 961 (68.89%) females remained in herds through the second parity, whereas 299 (31.11%) were removed before the second parity. Survival time for females on the basis of conformation scores for the forelimbs and hind limbs differed significantly for total sow removals and removals as a result of lameness. Females with poor conformation scores for the hind limbs had an increased risk of being removed, compared with risk for females with better conformation scores. Risk of removal specifically as a result of lameness increased as conformation score for the hind limbs became poorer. Proportion of the total population that was removed and could be attributed to undesirable limb conformation was 16.13% for forelimbs and 12.90% for hind limbs. CONCLUSIONS AND CLINICAL RELEVANCE: Females with undesirable conformation were removed earlier than females with desirable conformation. This was particularly true for females with low conformation scores for the hind limbs. Selection of gilts on the basis of limb conformation may result in reduced attrition of females and improved performance of herds over time.     

Clinical assessments of increased sensory sensitivity in dogs with cranial cruciate ligament rupture

Dogs with chronic pain have a compromised quality of life. Repeatable and accurate sensory assessments form a means by which the hypersensitivity likely to reflect chronic pain may be quantified. These assessments can be applied to individuals to identify those that may benefit from improved analgesic relief. In this study four sensory assessments were evaluated in dogs presenting with a naturally occurring chronic painful condition (cranial cruciate ligament rupture, CCLR) and were compared with healthy control animals of similar age and weight. Inter-digital von Frey filament and thermal sensitivity tests revealed that the affected hind limb of dogs with CCLR was significantly more sensitive than the opposing limb. Static weight bearing and gait parameter scores were also reduced in the affected hind limb compared to the opposing hind limb of dogs with CCLR; no such differences were found between the hind limbs of healthy (control) dogs. The quantitative sensory tests permitted the differentiation of limbs affected by CCLR from healthy limbs. Dogs presenting with CCLR demonstrate objectively quantitative sensory sensitivities, which may require additional consideration in case management.     

Multivariate statistical analysis of stride-timing measurements of nonfatigued racing Thoroughbreds

Standard univariate and bivariate statistical methods and two multivariate methods, stepwise regression and factor analyses, were used to analyze 17 stride-timing measurements of 22 racing Thoroughbreds filmed at the beginning of races. All horses were in a right-lead transverse gallop. Data were extracted from frame-by-frame analysis of 16-mm film taken with a high-speed camera. The mean stride duration was 0.405 s and the mean stride frequency was 2.47 strides/s. Stride duration had a higher correlation to the suspension-phase duration (r = 0.864) than to stride-stance-phase duration (r = 0.644). The 2 components of stride, the suspension and stride-stance phases, lasted on average, 0.114 s and 0.291 s or 28.07% and 72.01% of the stride duration, respectively. The correlation between stride-stance and suspension phases was low (r = 0.1767). Timing of the forelimbs, rather than overall stance-phase duration, may influence the duration of the suspension phase because four of seven variables selected in a stepwise-regression analysis were exclusively from the forelimbs. The stance-phase duration, and therefore swing-phase duration, of all four limbs differed significantly (P less than 0.05). The left forelimb (LF) and right hind limb (RH) had significantly shorter stance and single-support phases. Forelimb and hind limb pairs differed in their timing and coordination. There were differences in advanced placement and overlap of the hind limbs, compared with that in the forelimbs. Significant (P less than 0.05) differences were found between three limb overlap measurements. The overlap between the forelimbs was shortest and that between the hind limbs was the longest in duration.(ABSTRACT TRUNCATED AT 250 WORDS)     

Morphometric and anatomic study of the hind limb of a dog

OBJECTIVE: To obtain the anatomic and morphometric data required for biomechanical analysis of the hind limb in dogs. ANIMALS: A healthy adult mixed-breed 23-kg male dog. PROCEDURE: Following euthanasia of the dog, all muscles of the right hind limb were identified and meticulously removed. Physiologic cross-sectional areas (PCSA) and architectural indices (AI) were calculated. The coordinates for the origin and insertion of each muscle were determined, using orthogonal right-handed coordinate systems embedded in the pelvis, femur, and tibia. RESULTS: PCSA and AI were calculated for 29 muscles, and coordinates for the origins and insertions of these muscles were determined. CONCLUSIONS: Results provide the morphometric and anatomic data necessary for 3-dimensional biomechanical studies of the hind limb in dogs.     

Evaluation of gait kinetics in puppies with coxofemoral joint laxity

OBJECTIVE: To characterize ground reaction forces (GRFs) and determine whether there were correlations between forces and passive coxofemoral joint laxity in puppies. ANIMALS: Fifty-one 16-week-old hound-breed dogs. PROCEDURE: Force-plate gait evaluation and distraction radiographic imaging were performed. Ground reaction forces evaluated included x (mediolateral), y (craniocaudal breaking and propulsion), and z (vertical) peak force and impulse. Z-plane limb loading and unloading rates, loading interval, and weight distribution and y-plane stance time breaking and propulsion percentages were calculated. One-way ANOVA with the Duncan multiple range test was used to evaluate differences in gait variables among limbs. The relationships of left, right, highest, and mean distraction index (DI) with individual limb data of each dog were evaluated with the Spearman rank correlation. Left and right DIs were compared by means of linear regression analysis. RESULTS: Mean +/- SEM DI was 0.67 +/- 0.02. Left and right DIs were strongly correlated, but there were no significant relationships between DIs and gait variables. Most fore- and hind limb gait variables differed significantly, whereas paired fore- and hind limb gait variables did not. Asymmetry was most pronounced in the x- and y-planes. CONCLUSIONS AND CLINICAL RELEVANCE: GRFs were consistent with those of clinically normal mature dogs, supporting an absence of association between GRF and DI in young dogs. The GRFs and elucidation of the relationship between GRFs and DI may be useful for future studies in immature dogs.     

Hind limb kinematics during therapeutic exercises in dogs with osteoarthritis of the hip joints

Objective-To assess joint kinematics in dogs with osteoarthritis of the hip joints during walking up an incline or down a decline and over low obstacles and to compare findings with data for nonlame dogs. Animals-10 dogs with osteoarthritis of the hip joints (mean ± SD age, 6.95 ± 3.17 years; mean body weight, 34.33 ± 13.58 kg) and 8 nonlame dogs (3.4 ± 2.0 years; 23.6 ± 4.6 kg). Procedures-Reflective markers located on the limbs and high-speed cameras were used to record joint kinematics during walking up an incline or down a decline and over low obstacles. Maximal flexion, extension, and range of motion of the hip joints were calculated. Results-Osteoarthritis of the hip joints reduced extension of both hip joints and flexion of the contralateral hind limb, compared with flexion of the lame hind limb, during walking down a decline. Walking up an incline resulted in decreased extension of the stifle joint in both hind limbs of osteoarthritic dogs; extension was significantly decreased for the lame hind limb. During walking over low obstacles, maximal flexion of the stifle joint was increased significantly for the contralateral hind limb. Maximal flexion was increased in both tarsal joints. Conclusions and Clinical Relevance-Osteoarthritis of the hip joints led to complex changes in the gait of dogs, which involved more joints than the affected hip joint alone. Each exercise had specific effects on joint kinematics that must be considered when planning a rehabilitation program.     

Microwave thermography: a non-invasive technique for investigation of injury of the superficial digital flexor tendon in the horse.

Microwave thermographs were recorded from 77 normal horses. In 51% the lowest temperature was recorded in the mid-metacarpal region, and in 41% it was in the distal metacarpal region. The mean temperature of the normal limbs ranged from 25.04 to 37.4 degrees C. Maximum temperature differences between symmetrical points in both forelimbs ranged from 0 to 5.33 degrees C and differences in mean limb temperatures between both forelimbs ranged from 0 to 2.91 degrees C. In 48 horses with acute (less than 4 weeks' duration) injury of the superficial digital flexor tendon (SDFT) (36 unilateral, 12 bilateral) and 12 horses with acute injury of the soft tissues of the palmar metacarpal region other than the SDFT (all unilateral) 66% of forelimbs had acute SDFT injury, and 50% of those with other soft tissue injuries, had elevations of the temperature in the mid- or distal metacarpal region. Abnormal values for mean limb temperature, difference in mean limb temperature and maximum temperature difference between locations in opposite forelimbs were detected in 75% of the horses with SDFT injury and in only 16% of the horses with other soft tissue injury. The sensitivity of microwave thermography for the detection of SDFT injury was 81% and the specificity 74%. When 30 horses in National Hunt training were examined weekly for 5 weeks, 2 horses sustained SDFT injury during that period. The microwave thermographs recorded from these 2 horses, at 1 and 2 weeks before the onset of clinical signs, were abnormal. However, 16 horses which did not develop tendon injury also displayed thermographic abnormalities.     

Force plate analysis of the walking gait in healthy dogs

Ground reaction forces, impulses, and their relationships to morphometric measurements were evaluated for walking gait in 17 healthy dogs. A force plate was used to record forces at 1-ms intervals. Vertical, craniocaudal, and mediolateral forces were measured and normalized by body weight. Impulses, defined as the total force applied over time, were calculated in vertical and craniocaudal directions. Craniocaudal impulses were further divided into braking and propulsion phases. Braking impulses were significantly greater in the forelimbs (P less than or equal to 0.001), whereas propulsion impulses were generally greater in the hind limbs. Impulses and peak forces were then compared with morphometric measurements (body weight, humeral and femoral lengths, and paw length). All relationships were linear, with correlation coefficients significant (P less than or equal to 0.001). As the size of the dog increased, braking, propulsion and vertical impulses increased. Conversely, as morphometric measurements increased, peak vertical forces decreased. Thus, larger dogs had a lower peak force on each limb, but had a higher total impulse applied during stance phase. As stance phase time increased, peak vertical forces decreased. The results indicated that healthy dogs had significant correlations between ground reaction forces, impulses, and morphometric measurements.     

Evaluation of a novel accelerometer for kinetic gait analysis in dogs

The objective of this study was to evaluate a novel accelerometer-based sensor system, the Walkabout Portable Gait Monitor (WPGM), for use in kinetic gait analysis of dogs. The accelerometer was compared to the common reference standard of force platform analysis. Fifteen client-owned, orthopedically sound dogs of various breeds underwent simultaneous force platform and accelerometer gait trials to measure peak vertical forces (PVFs). The agreement between PVF for the accelerometer and force platform was measured using concordance correlation coefficient (CCC) and was found, overall, to be moderate [CCC = 0.51; 95% confidence interval (CI): 0.46 to 0.56]. The agreement between PVF for the accelerometer and force platform for the forelimbs was positive and substantial (CCC = 0.79; 95% CI: 0.74 to 0.84) and for the hind limbs was positive and low (CCC = 0.34; 95% CI: 0.29 to 0.38). As measured by the accelerometer, PVF was systematically higher than as measured by the force platform (forelimbs 55.3 N, hind limbs 144.3 N). It was also found that, when positioned over the lumbar spine, the WPGM cannot measure PVF of the individual forelimbs and hind limbs, which limits its use as a clinical tool to measure kinetic variables in dogs.     

Vertical position of the patella in the stifle joint of clinically normal large-breed dogs

OBJECTIVE: To define the vertical position of the patella in clinically normal large-breed dogs. SAMPLE POPULATION: Cadavers of 13 clinically normal large-breed dog. PROCEDURE: Both hind limbs were harvested with intact stifle joints and mounted on a positioning device that allowed full range of motion of the stifle joint. Lateral radiographic views were obtained with the stifle joints positioned at each of 5 angles (148 degrees, 130 degrees, 113 degrees, 96 degrees, and 75 degrees). Vertical position of the patella through a range of motion was depicted on a graph of mean stifle angle versus corresponding mean proximal patellar position (PPP) and distal patellar position (DPP) relative to the femoral trochlea for each dog. Ratio of length of the patellar ligament to length of the patella (L:P) was determined for each dog. Overall mean, SD, and 95% confidence intervals for L:P were calculated for all dogs. RESULTS: Evaluation of vertical position of the patella through a range of motion revealed a nearly linear relationship between joint angle and PPP and joint angle and DPPF Evaluation of L:P results did not reveal significant differences between limbs (left or right) or among joint angles. Overall mean +/- SD L:P for all dogs was 1.68 +/- 0.18 (95% confidence interval, 1.33 to 2.03). CONCLUSIONS AND CLINICAL RELEVANCE: The L:P proved to be a repeatable measurement of vertical patellar position, which is independent of stifle angles from 75 degrees to 148 degrees.This measurement could be used as a quantitative method for diagnosing patella alta and patella baja in large-breed dogs.     

Comparison of the trotting gaits of Labrador Retrievers and Greyhounds

OBJECTIVE: To compare the trotting gaits of Labrador Retrievers and Greyhounds to determine whether differences in locomotion are attributable to differences in their manner of moving or to body size and shape differences between these 2 breeds. ANIMALS: 8 healthy 5-month-old Greyhounds and 5 healthy Labrador Retrievers between 6 and 18 months old. PROCEDURE: A series of 4 force platforms was used to record independent ground reaction forces on the forelimbs and hind limbs during trotting. Values of stride parameters were compared between breeds before and after normalization for size differences. Standard values of absolute and normalized stride period and stride length were determined from linear regressions of these parameters on relative (normalized) velocity. Forces were normalized to body weight and compared at the same relative velocity. RESULTS: Greyhounds used fewer, longer strides than the Labrador Retrievers to travel at the same absolute speed. After normalization for body size differences, most measurable differences between breeds were eliminated. Subtle differences that did persist related to proportion of the stride that the forefoot was in contact with the ground, timing of initial hind foot contact relative to initial forefoot contact, and distribution of vertical force between the forelimbs and hind limbs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that apparent differences in the trotting gait between Labrador Retrievers and Greyhounds are mainly attributable to differences in size, and that dogs of these 2 breeds move in a dynamically similar manner at the trot.     

The influence of breed,age, gender,training level and ambient temperature on forelimb and back temperature in racehorses

A previous thermographic study of racehorses identified 13 regions of interest (ROIs) for monitoring the impact of training. However, that investigation did not consider the influence of breed, age, gender or training intensity level on the temperature of ROIs. The present study adopted a multivariate analysis approach to determine whether the aforementioned factors, along with ambient temperature, significantly influenced ROI temperature in the key body regions. Thermography measurements were obtained from 53 racehorses of three breeds. Horses were in regular training for over 10 months, having 13 thermographic examinations in each racing season. Backward stepwise multiple linear regression indicated that ambient temperature and breed contributed significantly to the model for predicting ROI temperature at all 13 ROIs. Training intensity level contributed significantly to the model only at the thoracic vertebrae, the left third metacarpal bone and left fetlock joint. Neither gender nor age contributed to the model significantly at any ROI. Our data suggest that ambient temperature, breed and training level affect racehorse body surface temperature in some areas of the distal parts of the forelimbs and the back. This contributes to a better understanding of the normal range of thermographic findings in racehorses undergoing intensive training.     

An investigation into the depth of penetration of low level laser therapy through the equine tendon in vivo

Low level laser therapy (LLLT) is frequently used in the treatment of wounds, soft tissue injury and in pain management. The exact penetration depth of LLLT in human tissue remains unspecified. Similar uncertainty regarding penetration depth arises in treating animals. This study was designed to test the hypothesis that transmission of LLLT in horses is increased by clipping the hair and/or by cleaning the area to be treated with alcohol, but is unaffected by coat colour. A LLLT probe (810 nm, 500 mW) was applied to the medial aspect of the superficial flexor tendon of seventeen equine forelimbs in vivo. A light sensor was applied to the lateral aspect, directly opposite the laser probe to measure the amount of light transmitted. Light transmission was not affected by individual horse, coat colour or leg. However, it was associated with leg condition (F = 4.42, p = 0.0032). Tendons clipped dry and clipped and cleaned with alcohol, were both associated with greater transmission of light than the unprepared state. Use of alcohol without clipping was not associated with an increase in light transmission. These results suggest that, when applying laser to a subcutaneous structure in the horse, the area should be clipped and cleaned beforehand.     

ULTRASOUND APPROACH TO THE CANINE DISTAL TIBIA AND TROCHLEAR RIDGES OF THE TALUS

The aim of the present study was to evaluate to what extent the distal tibia and the trochlear ridges of the talus can be examined with ultrasound (US) in the dog and to establish a protocol for an optimal US examination of these ridges. Six hind limbs of deceased adult mixed-breed dogs were used. In two limbs, needles were placed using US guidance on the trochlea of the talus, just dorsal to and plantar to the distal tibia: one with the tarsal joint in extension and one with the joint in flexion. Then mediolateral (ML) radiographs of both joints were made with the needle in place to determine the percentage of the trochlear ridge of the talus that can be seen using US imaging. An US examination of the tarsal joint was performed on the four other limbs using microconvex (8 MHz) and linear (12 MHz) transducers (Logiq 7) and compound imaging. A three-step protocol was performed including a dorsal approach with the limb extended and the linear transducer (step I), a plantar approach with the limb flexed and the linear transducer (step II), and a plantar approach with the limb flexed and the microconvex transducer (step III). After the US examination, the four limbs were frozen and sectioned, two in a transverse and two in a sagittal plane. Bony structures on the US images were matched with the corresponding anatomic sections. The distal tibia and both trochlear ridges of the talus were easily recognized on the US images using the proposed protocol. When combining the dorsal and plantar approaches, it was possible to visualize up to 75% of the trochlear ridges of the talus in the dog.