The impact of surgical correction of cranial cruciate ligament-deficient stifles (CCDS) on the 3-dimensional (3D) kinematics of the canine stifle has been sparsely evaluated. Tightrope (TR) cranial cruciate ligament (CCL) has been proposed to restore baseline 3D kinematics in CCDS by using isometric points. We hypothesized that TR would restore baseline 3D kinematics of the stifle in our model. Ten pelvic limbs were used with a previously validated apparatus. Three experimental conditions were evaluated: i) intact stifle, ii) cranial cruciate ligament transection (CCLt), and iii) CCLt stabilized with TR; kinematic data was recorded. Tightrope CCL in CCDS did not limit sagittal flexion. Tightrope CCL neutralized internal rotation without restoring baseline curves, but it did not restore abduction, nor did it neutralize or restore cranial translation, but it did restore latero-medial and proximo-distal translations. In our model, TR without pre-conditioning of the FiberTape strands did not restore baseline stifle 3D kinematics and residual cranial translation could result in frequent meniscal tears.

OBJECTIVE To compare the kinematics of the thoracic limb of healthy dogs during descent of stairs and a ramp with those during a trot across a flat surface (control). ANIMALS 8 privately owned dogs. PROCEDURES For each dog, the left thoracic limb was instrumented with 5 anatomic markers to facilitate collection of 2-D kinematic data during each of 3 exercises (descending stairs, descending a ramp, and trotting over a flat surface). The stair exercise consisted of 4 steps with a 35° slope. For the ramp exercise, a solid plank was placed over the steps to create a ramp with a 35° slope. For the flat exercise, dogs were trotted across a flat surface for 2 m. Mean peak extension, peak flexion, and range of movement (ROM) of the shoulder, elbow, and carpal joints were compared among the 3 exercises. RESULTS Mean ROM for the shoulder and elbow joints during the stair exercise were significantly greater than during the flat exercise. Mean peak extension of the elbow joint during the flat exercise was significantly greater than that during both the stair and ramp exercises. Mean peak flexion of the elbow joint during the stair exercise was significantly greater than that during the flat exercise. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that descending stairs may be beneficial for increasing the ROM of the shoulder and elbow joints of dogs. Descending stair exercises may increase elbow joint flexion, whereas flat exercises may be better for targeting elbow joint extension.

Objective: To validate an equine inertial measurement unit (IMU) system rigidly attached to a hoof against a 3-D optical kinematics system in horses during walking and trotting. Animals: 5 clinically normal horses. Procedures: 5 swing phases of the hooves of the right forelimb and hind limb were collected via both 3-D optical and IMU systems from 5 horses during walking and trotting. Linear and angular positions, velocities, and accelerations were compared between the 2 systems. Results: Of the 55 variables compared between the 2 systems, 25 had high correlations (r > 0.8) and 18 had moderate correlations (r > 0.5). Root mean squared errors were lowest in the sagittal plane and orientation (1.1 to 4.4 cm over a range of 1.5 to 1.9 m in the cranial-caudal direction and 2.5° to 3.5° over a range of 88° to 110° rotating around the medial-lateral axis). There were more differences between the 2 systems during small changes in motion, such as in the medial-lateral and proximal-distal directions and in the angular measures around the cranial-caudal and proximal-distal axes. Conclusions and Clinical Relevance: The equine IMU system may be appropriate for rigid attachment to a hoof of a horse and use in examination of linear and angular motion in the sagittal plane of the hoof during the swing phase while walking and trotting. Although promising in many respects, the IMU system cannot currently be considered clinically useful for lameness evaluation because of limitations in accuracy, attachment method, and lack of stance phase evaluation.

Six horses, highly trained for dressage competition, were used to study the stride kinematics of the walk, and to compare the kinematics of the collected, medium, and extended walks. Horses were filmed in a sagittal plane at a rate of 150 frames/s; temporal, linear, and angular data were extracted from the films. Results of ANOVA and Duncan's multiple range test indicated that the speed of the collected walk (1.37 m/s) was significantly (P < 0.01) slower than that of the medium (1.73 m/s) and extended (1.82 m/s) walks, values for which were not significantly different from each other. The increase in speed was associated with a significant increase in stride length, from 157 cm in the collected walk to 193 am in the extended walk. This was a result of an increase in the over-tracking distance, whereas there was no significant difference in the distance between lateral placements of the limbs. Stride duration decreased (P < 0.01) from the collected walk (1,159 ms) to the extended walk (1,064 ms). Angles of the metacarpal and metatarsal segments, measured on the palmar/plantar aspect, were higher at impact and lower at lift off in the collected than in the extended walk (P < 0.01). This indicated greater range of angular motion of this segment during the stance phase in the extended walk. Only 1 of the 6 horses had a regular 4-beat rhythm of the footfalls, with equal time elapsing between the lateral and diagonal footfalls.

High-speed cinematography was used to record the movements of 12 cutting horses performing a standard test with a mechanical flag. Based on their previous competitive performances, horses were classified into 2 groups: group 1, composed of 5 moderately successful or average performers that had won less than $35,000 in purse money; and group 2, composed of 7 highly successful or elite performers that had amassed greater than $35,000 in competition earnings. Analysis of the results indicated that, compared with horses of the average group, the elite horses had faster reaction times in response to the start and cessation of flag movement (P less than 0.01), and were positioned closer to the flag during all stages of the trial (P less than 0.05). Discriminant analysis was used to construct a mathematical formula that could be used to classify an individual horse into 1 of the 2 alternative groups, based on the set of measurements. Two predictor variables were selected that described the maximal distance between the horse and the flag during the run and the part of the body that was moved first in response to the initial flag movement. The accuracy of the predicted group membership, compared with the actual group membership, was 100%.

Strains of the suspensory ligament and deep digital flexor, superficial digital flexor, and long digital extensor tendons in the equine (pony) hind limb were recorded in vivo, using implanted strain gauges consisting of silicone rubber tubes filled with mercury. The relationship between strain gauge signals and tendon strains was obtained from tension-strain tests performed on isolated tendons after death of the ponies. During normal walking, maximal tendon strain (elongation over initial length, relative to the length of the structures at first ground contact) was 3.1% in the suspensory ligament and 3.4%, 2.3%, and 0.3% in the deep digital flexor, the superficial digital flexor, and the long digital extensor tendons, respectively. Changes (that occurred during walking) in the distance from origin to insertion of these musculotendinous structures were computed from limb geometric configuration and limb conformation. Maximal increase in origin to insertion length was 3.1% in the suspensory ligament and 2%, 1.6%, and 1.5% in the deep digital flexor, superficial digital flexor, and long digital extensor musculotendinous structures, respectively. The differences in strain, comparing the entire musculotendinous structure and its tendon, were explained by muscular contraction or relaxation.

OBJECTIVE To evaluate and quantify the kinematic behavior of canine mandibles before and after bilateral rostral or unilateral segmental mandibulectomy as well as after mandibular reconstruction with a locking reconstruction plate in ex vivo conditions. SAMPLE Head specimens from cadavers of 16 dogs (range in body weight, 30 to 35 kg). PROCEDURE Specimens were assigned to undergo unilateral segmental (n = 8) or bilateral rostral (8) mandibulectomy and then mandibular reconstruction by internal fixation with locking plates. Kinematic markers were attached to each specimen in a custom-built load frame. Markers were tracked in 3-D space during standardized loading conditions, and mandibular motions were quantified. Differences in mandibular range of motion among 3 experimental conditions (before mandibulectomy [ie, with mandibles intact], after mandibulectomy, and after reconstruction) were assessed by means of repeated-measures ANOVA. RESULTS Both unilateral segmental and bilateral rostral mandibulectomy resulted in significantly greater mandibular motion and instability, compared with results for intact mandibles. No significant differences in motion were detected between mandibles reconstructed after unilateral segmental mandibulectomy and intact mandibles. Similarly, the motion of mandibles reconstructed after rostral mandibulectomy was no different from that of intact mandibles, except in the lateral direction. CONCLUSIONS AND CLINICAL RELEVANCE Mandibular kinematics in head specimens from canine cadavers were significantly altered after unilateral segmental and bilateral rostral mandibulectomy. These alterations were corrected after mandibular reconstruction with locking reconstruction plates. Findings reinforced the clinical observations of the beneficial effect of reconstruction on mandibular function and the need for reconstructive surgery after mandibulectomy in dogs.

OBJECTIVE To describe qualitative blinking patterns and determine quantitative kinematic variables of eyelid motion in ophthalmologically normal horses. ANIMALS 10 adult mares. PROCEDURES High-resolution videography was used to film blinking behavior. Videotapes were analyzed for mean blink rate, number of complete versus incomplete blinks, number of unilateral versus bilateral blinks, and subjective descriptions of blinking patterns. One complete blink for each horse was analyzed with image-analysis software to determine the area of corneal coverage as a function of time during the blink and to calculate eyelid velocity and acceleration during the blink. RESULTS Mean ± SD blink rate was 18.9 ± 5.5 blinks/min. Blinks were categorized as minimal incomplete (29.7 ± 15.6%), moderate incomplete (33.5 ± 5.9%), complete (30.8 ± 13.1%), and complete squeeze (6.0 ± 2.8%); 22.6 ± 9.0% of the blinks were unilateral, and 77.3 ± 9.1% were bilateral. Mean area of exposed cornea at blink initiation was 5.89 ± 1.02 cm2. Mean blink duration was 0.478 seconds. Eyelid closure was approximately twice as rapid as eyelid opening (0.162 and 0.316 seconds, respectively). Deduced maximum velocity of eyelid closure and opening was −16.5 and 7.40 cm/s, respectively. Deduced maximum acceleration of eyelid closure and opening was −406.0 and −49.7 cm/s2, respectively. CONCLUSIONS AND CLINICAL RELEVANCE Kinematic variables of ophthalmologically normal horses were similar to values reported for humans. Horses had a greater percentage of complete squeeze blinks, which could increase tear film stability. Blinking kinematics can be assessed as potential causes of idiopathic keratopathies in horses.

Objective—To quantify the 3-D kinematics and collateral ligament strain of stifle joints in cadaveric canine limbs before and after cranial cruciate ligament transection followed by total knee replacement (TKR) involving various tibial plateau angles and spacer thicknesses. Sample—6 hemi-pelvises collected from clinically normal nonchondrodystrophic dogs (weight range, 25 to 35 kg). Procedures—Hemi-pelvises were mounted on a modified Oxford knee rig that allowed 6 degrees of freedom of the stifle joint but prevented mechanical movement of the hip and tarsal joints. Kinematics and collateral ligament strain were measured continuously while stifle joints were flexed. Data were again collected after cranial cruciate ligament transection and TKR with combinations of 3 plateau angles (0°, 4°, and 8°) and spacer thicknesses (5, 7, and 9 mm). Results—Presurgical (ie, normal) stifle joint rotations were comparable to those previously documented for live dogs. After TKR, kinematics recorded for the 8°, 5-mm implant most closely resembled those of unaltered stifle joints. Decreasing the plateau angle and increasing spacer thickness altered stifle joint adduction, internal rotation, and medial translation. Medial collateral ligament strain was minimal in unaltered stifle joints and was unaffected by TKR. Lateral collateral ligament strain decreased with steeper plateau angles but returned to a presurgical level at the flattest plateau angle. Conclusions and Clinical Relevance—Among the constructs tested, greatest normalization of canine stifle joint kinematics in vitro was achieved with the steepest plateau angle paired with the thinnest spacer. Furthermore, results indicated that strain to the collateral ligaments was not negatively affected by .

Objective: To assess differences in sagittal plane joint kinematics and ground reaction forces between lean and obese adult dogs of similar sizes at 2 trotting velocities. Animals: 16 adult dogs. Procedures: Dogs with body condition score (BCS) of 8 or 9 (obese dogs; n = 8) and dogs with BCS of 4 or 5 (lean dogs; 8) on a 9-point scale were evaluated. Sagittal plane joint kinematic and ground reaction force data were obtained from dogs trotting at 1.8 and 2.5 m/s with a 3-D motion capture system, a force platform, and 12 infrared markers placed on bony landmarks. Results: Mean stride lengths for forelimbs and hind limbs at both velocities were shorter in obese than in lean dogs. Stance phase range of motion (ROM) was greater in obese dogs than in lean dogs for shoulder (28.2° vs 20.6°), elbow (23.6° vs 16.4°), hip (27.2° vs 22.9°), and tarsal (38.9° vs 27.9°) joints at both velocities. Swing phase ROM was greater in obese dogs than in lean dogs for elbow (61.2° vs 53.7°) and hip (34.4° vs 29.8°) joints. Increased velocity was associated with increased stance ROM in elbow joints and increased stance and swing ROM in hip joints of obese dogs. Obese dogs exerted greater peak vertical and horizontal ground reaction forces than did lean dogs. Body mass and peak vertical ground reaction force were significantly correlated. Conclusions and Clinical Relevance: Greater ROM detected during the stance phase and greater ground reaction forces in the gait of obese dogs, compared with lean dogs, may cause greater compressive forces within joints and could influence the development of osteoarthritis.