Tubera Coxae Research Articles

Effect of speed and water depth on limb and back kinematics in Thoroughbred horses walking on a water treadmill

Water treadmill (WT) exercise may induce limb and back kinematics that meet specific training and rehabilitation goals. The study aimed to investigate the effects of walk speed, at different water depths (WDs), on limb and back kinematics of six Thoroughbreds exercising on a WT. Horses walked at 2.8/4.3/5.5/6.0 km/h (i.e. 0.8/1.2/1.5/1.7 m/s) at dry, metacarpophalangeal and carpal WD. Videography captured limb movement in the sagittal plane. Motion-capture measured thoracolumbosacral flexion-extension (FE), and lateral bend (LB) ranges of movement (ROM) using skin surface markers on the sixth, tenth, thirteenth, eighteenth thoracic, third and fifth lumbar, and third sacral spinous processes. Inertial-motion-sensors measured poll, withers and pelvic displacements. Following preliminary univariable analyses, multivariable mixed-effects linear-regression analyses were used to examine the relationship between speed, WD and each outcome variable (P < 0.05). Peak metacarpophalangeal, carpal and tarsal joint flexion increased with speed (P ≤ 0.002) and depth combined (P 0.001) while peak metatarsophalangeal flexion increased with WD only (P 0.001). Thoracolumbar FE-ROM between T10 and L3 and hindlimb retraction was increased by speed and WD combined (P 0.001). Hindlimb protraction was increased by speed (P 0.001) while hindlimb retraction was increased by speed and WD combined (P 0.001). Dorsoventral poll displacement was increased by speed (P 0.001) and carpal WD (P = 0.013), craniocaudal poll displacement was increased by speed and WD combined (P 0.001). Pelvic (tubera coxae and sacrum) dorsoventral displacements increased with speed and WD combined (P 0.001). Understanding the effects of speed and WD on limb, back and pelvic kinematics will improve decision making relating to dry and WT exercise within training.

Back motion in unridden horses in walk, trot and canter on a circle

Equine back function is of concern to riders, as well as to veterinarians and physiotherapists; these groups may benefit from knowledge about spinal motion on the circle. This descriptive and comparative study aimed to quantify equine neck, back and pelvic motion in walk, trot and canter on a 9 m circle. Sixteen healthy horses in training, of varying breed and conformation, were measured using optical motion capture (150 Hz), with optical markers on the poll, withers, T15, tubera coxae and lumbosacral joint. Cervicothoracic and thoracolumbar flexion–extension and lateral bending, and pelvic roll, pitch and yaw, were statistically evaluated using mixed models. Motion patterns showed distinct differences between gaits, but were generally similar between horses. The thoracolumbar back was bent towards the inside of the circle (stride mean 5-6º for all gaits). The cervicothoracic spine was more flexed in walk (18°), and more extended in canter (-4—-8°), compared to trot (6–7°), whereas the thoracolumbar spine was slightly less extended in canter than in walk. Thoracolumbar flexion–extension range of motion (ROM) increased from walk (4°) to canter (9°), as did pelvic pitch ROM (walk 7° and canter 15–16°), while back lateral bending ROM and pelvic yaw ROM were lowest in trot. Taken together, the study findings suggest that neck and back motion patterns on the circle reflect an interaction between the constraints of circular movement, and the mechanics and characteristics of each gait.

Effect of Water Depth on Limb and Back Kinematics in Horses Walking on a Water Treadmill.

Water treadmill (WT) exercise is frequently used for training/rehabilitation of horses. There is limited study into the effect of water depth on limb/back kinematics warranting investigation. The objective was to determine the effect of walking in different water depths, at the same speed, on limb/back kinematics measured simultaneously in a group of horses. Six horses (age:15 ± 6.5 years) completed a standardized WT exercise session (19 minutes duration; speed:1.6 m/s; water depths: 0.0/7.5/21.0/32.0/47.0 cm). Ten waterproof light-emitting-diode tea-light-markers and reflective-spheres were affixed to the skin at predetermined locations; inertial-measurement-units were fixed to the poll/withers/left and right tubera coxae (TC)/sacrum to determine range-of-motion (ROM) changes of these locations. Univariable-mixed-effects-linear-regression-analyses were carried out, with a significance value of P ≤ .05. At maximum carpal/tarsal flexion during swing, regression analyses showed a clear and consistent nonlinear increase in carpal and tarsal flexion at increasing water depths (P < 0.0001 for both variables). As water depth increased there was a significant increase in thoracic spine flexion-extension ROM (P < 0.0001 at all thoracic sites) and increased dorsoventral and mediolateral ROM of the sacrum/left and right TC (P < 0.001 for all variables) as water depth increased. Results suggest that horses responded to an increase in water depth until a threshold depth was reached when the biomechanical response levelled off, and there was increased pelvic roll. In conclusion, changes in limb kinematics brought about by relatively modest increases in water depth at walking speed of 1.6 m/s are sufficient to induce significant changes in back/pelvic movement highlighting key issues with relevance for WT program design.

The Effect That Induced Rider Asymmetry Has on Equine Locomotion and the Range of Motion of the Thoracolumbar Spine When Ridden in Rising Trot

There is a paucity of evidence on the effect that rider asymmetry has on equine locomotion. The aim of this study was to evaluate the effect of rider asymmetry on equine locomotion by using a novel approach to induce rider asymmetry. Ten nonlame horses were recruited for this study. Joint center markers were used to capture 2D kinematics (Quintic Biomechanics) of the horse and rider and horses were equipped with seven inertial sensors positioned at the fifth (T5) and eighteenth (T18) thoracic vertebrae, third lumbar (L3) vertebra, tubera sacrale (TS), and left and right tubera coxae. Rider asymmetry was induced by shortening the ventral aspect of one stirrup by 5 cm. Kinematic data were compared between conditions using a mixed model with the horse defined as a random factor and stirrup condition (symmetrical stirrups and asymmetrical stirrups) and direction (inside and outside) defined as fixed factors. Data from riders where the right stirrup was shortened were mirrored to reflect a left stirrup being shortened. To determine differences between conditions, a significance of P ≤ .05 was set. On the rein with the shortened stirrup on the outside: an increase in lateral bending range of motion (ROM) at T5 (P = .003), L3 (P = .04), and TS (P = .02), an increase in mediolateral displacement at T5 (P = .04), T18 (P = .04), and L3 (0.03) were found. An increase in maximum fetlock extension was apparent for both the front (P = .01) and hind limb (P = .04) on the contralateral side to the shortened stirrup; for the asymmetrical stirrup condition on the rein with the shortened stirrup on the inside: an increase in flexion-extension ROM at T5 (P = .03) and L3 (P = .04), axial rotation at T5 (P = .05), and lateral bending of T5 (P = .03), L3 (P = .04), and TS (P = .02). Asymmetric rider position appears to have an effect on the kinematics of the thoracolumbar spine. These findings warrant further investigation to understand the long-term impact this may have on equine locomotor health.

The effects of rider size and saddle fit for horse and rider on forces and pressure distribution under saddles: A pilot study

SummaryThere is limited scientific evidence concerning the effect of rider weight on pressures under the saddle and equine performance. The objective of this prospective, crossover, randomised trial was to assess pressure distribution and magnitude in horses ridden by four riders of similar ability but differing in bodyweight and height. Six horses in regular work were ridden by four riders (rider bodyweight: horse body weight percentage &gt; 10 ≤ 12 [L = Light], &gt; 12 ≤ 15 [M = Moderate], &gt; 15 ≤ 18 [H = Heavy] and &gt; 20 [VH = Very Heavy]), performing a purpose‐designed dressage test (30 min). The test was abandoned for ≥ grade 3/8 lameness or ≥ 10 behavioural markers (assessed in real‐time). A calibrated force mat (Pliance) was used to record pressures under the saddle in walk, trot and canter on left and right reins. Rider position was assessed. All 13 H and VH tests and one of 12 M rider tests were abandoned (lameness, n = 12; behaviour, n = 1). At walk, the seat of riderVHextended beyond the cantle of the saddle; rider H sat on the cantle of the saddle. At trot and canter the heels of riderVHwere consistently cranial to the tubera coxae and shoulders. Pressures were significantly higher under the caudal aspect of the saddle compared with cranially for riderVHin walk (P&lt;0.05, ANOVA, Bonferroni). At rising trot pressures were higher cranially for riders L, M and H (P&lt;0.05, ANOVA, Bonferroni), but were similar cranially and caudally for riderVH. The highest maximum peak pressure was recorded for riderVHin canter. A limitation was that speed can alter pressure measurements, but was not controlled or recorded. We concluded that there were differences in magnitude and distribution of pressures among the four riders according to their size, which may have contributed to the development of musculoskeletal pain. This may also have been influenced by saddle fit for riders and their positions.

Quantification of the effect of instrumentation error in objective gait assessment in the horse on hindlimb symmetry parameters.

SummaryBackgroundObjective gait analysis is becoming more popular as a tool assisting veterinarians during the clinical lameness exam. At present, there is only limited information on the effect of misplacement of markers/motion‐sensors.ObjectivesTo investigate and describe the effect of marker misplacement on commonly calculated pelvic symmetry parameters.Study designExperimental study.MethodsEach horse was equipped with custom‐made devices consisting of several reflective markers arranged in a predefined manner with a reference marker correctly positioned regarding the anatomical landmark and several misplaced markers along the sagittal and transverse planes. Linear regression analysis was used to estimate the effect of marker misplacement.ResultsFor the tubera sacrale, each cm of left/right misplacement led to a difference in minimum position of the pelvis (PDmin) of ±1.67 mm (95% CI 1.54–1.8 mm) (P<0.001); maximum position of the pelvis (PDmax) was affected by ±0.2 mm (95% CI 0.071–0.33 mm) (P = 0.003). With respect to cranial/caudal misplacement, each cm of misplacement resulted in a PDmin difference of ±0.04 mm (95% CI −0.09 to 0.16 mm) (P = 0.56) and a PDmax difference of ±0.008 mm (95% CI −0.13 to 0.12 mm) (P = 0.9). For the tubera coxae, each cm of vertical misplacement led to a difference in the displacement amplitude between left and right tubera coxae (Hip‐Hike_Diff) of ±1.56 mm (95% CI 1.35–1.77 mm) (P<0.001); for the cranial/caudal misplacement, this was ±0.82 mm (95% CI 0.66–0.97 mm) (P<0.001).Main limitationsOnly three horses were used in this experiment and the study design did not permit to determine the influence of marker misplacement on the evaluation of different degrees of lameness.ConclusionsMarker misplacement significantly affects calculated symmetry parameters of the pelvis. The observed errors are overall small but significant. In cases of mildly asymmetrical horses, this error might influence the decision‐making process whereas in more severe asymmetries, the influence of the error effect may become less significant.

Alterations in thoracolumbosacral movement when pain causing lameness has been improved by diagnostic analgesia

Lameness, thoracolumbosacral pain and reduced range of motion (ROM) often coexist; better understanding of their relationship is needed. The objectives were to determine if thoracolumbosacral movement of horses changes when pain causing lameness is improved by diagnostic analgesia. We hypothesised that reduction of lameness will increase ROM of the thoracolumbosacral region. Thirteen horses with different types of hind limb lameness were trotted in straight lines and lunged on a 10m diameter circle on left and right reins before and after lameness was subjectively substantially improved by diagnostic analgesia. Inertial sensor data were collected from the withers, thirteenth (T13) and eighteenth thoracic (T18) vertebrae, third lumbar (L3) vertebra, tubera sacrale (TS), left and right tubera coxae. ROM of flexion-extension, axial rotation, lateral bending, dorsoventral, lateral-lateral motion and vertical movement symmetry were quantified at each thoracolumbar site. Hiphike difference (HHD), maximum difference (MaxDiff) and minimum difference (MinDiff) for the pelvic sensors were measured. Percentage changes for before and after diagnostic analgesia were calculated; mean±standard deviation (SD) or median [interquartile range] were determined.Associations between the change in pelvic versus thoracolumbar movement symmetry after each local analgesic technique were tested. After resolution of lameness, HHD decreased by 7% [68%] (P=0.006). The MinDiff decreased significantly by 33% [61%] (P=0.01), 45±13% (P=0.005) and 52±23% (P=0.04), for TS, L3 and T18, respectively. There was significantly increased ROM in flexion-extension at T13, in axial rotation at T13, T18, L3 and in lateral-lateral ROM at L3. Thoracolumbosacral asymmetry and reduced ROM associated with lameness were both altered immediately by improvement in lameness using diagnostic analgesia.

Thoracolumbar movement in sound horses trotting in straight lines in hand and on the lunge and the relationship with hind limb symmetry or asymmetry

Equine movement symmetry is changed when turning, which may induce alterations in thoracolumbosacral kinematics; however, this has not previously been investigated. Our objectives were to document thoracolumbar movement in subjectively sound horses comparing straight lines with circles on both reins and to relate these observations to the objectively determined symmetry/asymmetry of hindlimb gait. Fourteen non-lame horses were assessed prospectively in a non-random, cross-sectional survey. The horses were trotted in straight lines and lunged on both reins and inertial sensor data collected at landmarks: withers, T13 and T18, L3, tubera sacrale, and left and right tubera coxae. Data were processed using published methods; angular motion range of motion (ROM; flexion-extension, axial rotation, lateral bending) and translational ROM (dorsoventral and lateral) and symmetry within each stride were assessed.The dorsoventral movement of the back exhibited a sinusoidal pattern with two oscillations per stride. Circles induced greater asymmetry in dorsoventral movement within each stride (mean ± standard deviation, up to 9 ± 6%) compared with straight lines (up to 6 ± 6%). The greatest amplitude of dorsoventral movement (119 ± 14 mm in straight lines vs. 126 ± 20 mm in circles) occurred at T13. Circles induced greater flexion-extension ROM (>1.3°; P = 0.002), lateral bending (>16°; P < 0.001), and lateral motion (>16 mm; P = 0.002) compared with straight lines. Circles induced a movement pattern similar to an inside hindlimb lameness, which was significantly associated with the circle-induced greater asymmetry of dorsoventral movement of the thoracolumbar region (P = 0.03). Moving in a circle induces measurable changes in thoracolumbar movement compared with moving in straight lines, associated with alterations in the hindlimb gait.

Thoracolumbar Movement in Sound Horses Trotting in Hand and on the Lunge

Reasons for performing studyLameness negatively affects the welfare of horses; it often coexists with thoracolumbar pain. The mechanisms linking the two are not well understood.ObjectivesTo document thoracolumbar movement in subjectively sound horses comparing straight lines with circles on left and right reins; to relate these observations to the objectively determined symmetry/asymmetry of hindlimb gait.Study designCross‐sectional study.MethodsFourteen non‐lame horses were trotted in straight lines and lunged on a 10 m diameter circle on left and right reins and inertial sensor data collected at landmarks: withers, 13th (T13) and 18th thoracic vertebrae, 3rd lumbar vertebra, tubera sacrale, left and right tubera coxae. Data were processed using published methods [1]; pitch and roll, dorsoventral and lateral motion and symmetry within each stride were assessed.ResultsDorsoventral motion during one stride had a sinusoidal pattern with 2 oscillations. The greatest amplitude and symmetry (119 ± 4 mm, 96 ± 1% in straight lines vs. 127 ± 5 mm, 94 ± 1% in circles) occurred at T13. Circles induced greater rotation around the transverse axis (&gt;1.3°, P = 0.002) and movement in a lateral direction (&gt;16 mm P = 0.002), greater dorsoventral amplitude and asymmetry; however, the latter differences were nonsignificant. There were no significant differences between reins. The difference in the left and right hindlimb stance phases and the 2 oscillations of the thoracolumbar were significantly associated. Greater circle‐induced upward movement of a tuber coxae during the contralateral hindlimb stance was associated with greater circle‐induced asymmetry of the 2 oscillations of the thoracolumbar (P = 0.04).ConclusionsMoving on a circle induces measurable changes in thoracolumbar movement compared with moving in straight lines, associated with alterations in the hindlimb gait.Ethical animal research: The study was approved by the Ethical Review Committee of the Animal Health Trust. Owners gave informed consent for their horses' inclusion in the study. Source of funding: RVC PhD funding of Line Greve. Competing interests: None declared.

Understanding hind limb lameness signs in horses using simple rigid body mechanics

Hind limb lameness detection in horses relies on the identification of movement asymmetry which can be based on multiple pelvic landmarks. This study explains the poorly understood relationship between hind limb lameness pointers, related to the tubera coxae and sacrum, based on experimental data in context of a simple rigid body model. Vertical displacement of tubera coxae and sacrum was quantified experimentally in 107 horses with varying lameness degrees. A geometrical rigid-body model of pelvis movement during lameness was created in Matlab. Several asymmetry measures were calculated and contrasted. Results showed that model predictions for tubera coxae asymmetry during lameness matched experimental observations closely. Asymmetry for sacrum and comparative tubera coxae movement showed a strong association both empirically (R2≥0.92) and theoretically. We did not find empirical or theoretical evidence for a systematic, pronounced adaptation in the pelvic rotation pattern with increasing lameness. The model showed that the overall range of movement between tubera coxae does not allow the appreciation of asymmetry changes beyond mild lameness. When evaluating movement relative to the stride cycle we did find empirical evidence for asymmetry being slightly more visible when comparing tubera coxae amplitudes rather than sacrum amplitudes, although variation exists for mild lameness. In conclusion, the rigidity of the equine pelvis results in tightly linked movement trajectories of different pelvic landmarks. The model allows the explanation of empirical observations in the context of the underlying mechanics, helping the identification of potentially limited assessment choices when evaluating gait.

Fifty Ways to Do Your Lameness: The Relationship Between Various Pelvis‐Based Visual Lameness Pointers During Hindlimb Lameness

Reasons for performing studyThe relationship between pelvic hindlimb lameness pointers remains unclear.ObjectivesTo examine sacrum and tubera coxae (TC) based movement asymmetry across different lameness degrees, patterns and changes in pelvic rotation.Study designParameter regression and rigid body model.MethodsVertical displacement of left and right tubera coxae (LTC, RTC) and sacrum was quantified experimentally in 107 horses with varying lameness degrees using inertial sensors. To investigate the theoretical relationship between pointers, a geometrical model of pelvis movement was created in Matlab. The model predicts TC movement based on experimentally derived pelvic rotation and computer‐generated asymmetrical sacrum movement. Further, the effect of changes in pelvic rotation on TC‐based lameness pointers was quantified. For both, experimental and model data, asymmetry measures corresponding to visual assessment strategies of veterinarians were calculated and contrasted.ResultsExperimental data showed that upward movement amplitudes for sacrum and TC were strongly correlated (r ≥ 0.96). Regression showed that differences were greater between amplitudes of LTC/RTC than sacrum (slope 1.18; r2 = 0.94; P&lt;0.001); however, for ratios the reverse held true (slope 0.86; r2 = 0.92; P&lt;0.001). The model predicted experimentally determined tubera coxae asymmetry well. While the model data matched the experimental scaling relationship between amplitude ratios, it predicted a slightly shallower slope for amplitude differences. Perturbing the model with a different rotational range of movement, an offset in pelvic rotation and asymmetrical pelvic rotation affected observable TC‐based asymmetry depending on the chosen assessment strategy.ConclusionsDetecting lameness based on sacrum or comparative TC movement can give similar results. Using comparative TC movement for lameness detection would be susceptible to changes in pelvic rotation which a lame horse may adopt. Hence, assessment of multiple pelvis‐based lameness pointers can help establishing nonobvious hindlimb lameness.Ethical animal research: The experimental component of this study was approved by the RVC Ethics Committee. Some horses were included with owner informed consent and data from clinical cases were recorded as part of lameness investigations. Sources of funding: S.D. Starke's PhD was funded by the Mellon Trust via the Royal Veterinary College. Competing interests: None.

Optimal Gait Parameters for Quantifying the Effect of Diagnostic Analgesia in Horses

IntroductionEvaluating responses of horses to diagnostic analgesia is subject to bias. Pelvic movement symmetry can be measured accurately with inertial sensors, but it is unclear which of the many symmetry measures best reflect changes. It was hypothesised that objective parameters mimicking commonly observed visual parameters used by veterinarians (difference between upward/downward sacral movement and between amplitudes of left and right tuber coxa motion) would show the largest, most consistent responses.Methods13 horses underwent visual lameness scoring and independent gait assessment with inertial sensors during clinical lameness investigations. Multiple movement symmetry parameters were calculated and changes before/after diagnostic analgesia regressed against change in lameness grade. Confidence intervals of slopes of regression lines were assessed to identify significant changes.ResultsAll parameters showed variation between horses and across lameness grades. Three measures documented a consistent increase in symmetry for each grade of change in lameness score: difference between sacral displacement minima, and upward movement difference and range of motion difference between the tubera coxae. A change in symmetry of 9–13% for each grade of increase in lameness can be expected.ConclusionsThe three most promising pelvic parameters for consistent quantification of changes due to diagnostic analgesia in the hindlimb of lame horses were identified. Difference in upward movement between left and right tuber coxae is the most sensitive but requires simultaneously focusing on pelvic and limb movements and may therefore be more difficult to assess visually. Showing a similar response to diagnostic analgesia, the difference in movement amplitude between left and right tuber coxae may be more easily perceived since it does not require simultaneous focus on limb movement.Ethical Animal ResearchThe study was approved by the local ethics committee. Explicit owner informed consent for participation in this study is not stated. Sources of funding: None declared. Competing interests: none.

Is Foot Placement Related to Body Movement Asymmetry During Circular Locomotion?

IntroductionThe mechanics of circular locomotion are relevant to equine training and lameness evaluation. Circular trotting is associated with asymmetries in upper body movement. This study investigated whether changes in foot placement explain upper body asymmetry and whether this asymmetry is dependent on centripetal force.MethodsSix functionally sound horses walked and trotted on a 6 m diameter circle and straight line at their preferred speed. Optical motion capture (Motion Analysis Corp.) recorded foot position in 3D space. For each limb, horizontal foot placement was calculated in a body‐based reference system. Vertical displacement asymmetry (Vector Sum, VS) was calculated from inertial sensors (Xsens, The Netherlands) attached above poll, withers, sacrum and tubera coxae. Variables were compared across movement directions and gaits using repeated measures ANOVA (parametric datasets) or Friedman Test (non‐parametric datasets).ResultsChanges in foot placement relative to body position and orientation were small for both gaits in cranio‐caudal and medio‐lateral direction (maximum effect size at walk/trot: 66/102 mm). The amount of systematic movement asymmetry on the circle was comparable between walk (mean VS head/sacrum: 36/15 mm) and trot (30/15 mm, respectively), despite a 3‐fold higher centripetal force during trot.ConclusionsFoot placement relative to body position and line of travel does not differ markedly between straight line and circle and cannot solely account for the observed upper body movement asymmetry. Since movement asymmetry was comparable at walk and trot (despite differences in adopted movement pattern), centripetal force may not be the primary variable responsible for movement asymmetry on the circle.Ethical Animal ResearchThe study was approved by the MSU Institutional Animal Care and Use Committee, protocol #06/11‐112‐00. Sources of funding: Sandra Starke's collaborative research visit for this project was funded by the British Society for Animal Science (BSAS), Murray Black Award. Competing interests: none.

Towards Reliable Objective Lameness Quantification on the Circle

IntroductionLungeing is part of the standard lameness examination, however it systematically affects movement symmetry even in sound horses. We evaluated a method for objective lameness detection on the circle accounting for this asymmetry bias.MethodsTwenty‐six horses undergoing lameness examination were equipped with inertial sensors (Xsens) on head, sacrum and tubera coxae. Asymmetry in vertical displacement was quantified for trot on straight line and circle using multiple measures. Horses were classified lame when falling outside the directional reference range of sound horses (directional = ‘normal’ margins and lame limb depending on rein and sign of measure). Objective classification on the circle was compared to subjective evaluation, final diagnoses and objective classification on the straight calculating the proportion of matches. Regression analysis evaluated the association of change in asymmetry between straight line and circle and baseline asymmetry on the straight.ResultsThe match between objective classification on the circle and the exact fore‐/hindlimb(s) scored lame subjectively was 81% / 79%. The match with the diagnosed limb(s) was 71% / 85%. There was a high frequency of false positives compared to subjective evaluation. Objective evaluation on the circle added new information compared to assessment on the straight line in 70% (forelimb) / 58% (hindlimb) of instances (contralateral limb lame, bilateral lameness, lame on circle but sound on straight). Change in asymmetry was not associated with baseline lameness (P≥0.062).ConclusionsObjective lameness evaluation on the circle makes a valuable contribution to patient assessment: e.g. subtle lameness falling within the margins of ‘normal’ on the straight or bilateral lameness could be identified. In future, the predictive value of the proposed technique should be determined.Ethical Animal ResearchThe study was approved by the local ethics committee. Explicit owner informed consent for participation in this study is not stated. Sources of funding: Sandra Starke's PhD studentship was funded through the Mellon Trust via the Royal Veterinary College. Competing interests: none.

Identifying optimal parameters for quantification of changes in pelvic movement symmetry as a response to diagnostic analgesia in the hindlimbs of horses

Subjective evaluation of the response to diagnostic analgesia of hindlimb lameness is influenced by expectation bias. Quantification of pelvic movement with inertial measurement units is possible, but it is unclear which measure of movement symmetry best reflects the changes seen after diagnostic analgesia. To test our hypothesis that objective measures closely relating to those used for subjective visual lameness scoring (quantifying the difference between sacral upward or downward movement or between movement amplitudes of the left and right tubera coxae) would show the largest and most consistent response. Retrospective analysis of subjective and objective clinical lameness data. Thirteen horses with hindlimb lameness underwent visual lameness scoring and independent gait assessment with inertial measurement units. Established objective measures were calculated and changes before/after diagnostic analgesia regressed against the change in lameness grade. Slopes of regression lines were calculated and confidence intervals assessed. All objective parameters showed variation between horses and across lameness grades. The following 3 measures documented a consistent increase in symmetry for each grade of change in lameness score: difference between sacral displacement minima; upward movement difference; and range of motion difference between the tubera coxae. Several pelvic parameters are suitable for objective quantification of changes after diagnostic analgesia in hindlimb-lame horses. A change of 9-13% per lameness grade can be expected. Upward movement of the tubera coxae is the most sensitive objective measure for quantifying a response to diagnostic analgesia. However, when assessed visually, this measure requires simultaneous focusing on pelvic and limb movements. Other parameters that show a similar response might be more easily perceived, requiring only assessment of tubera coxae range of motion or downward displacement of the sacrum without simultaneous focus on limb movement.

Pelvic Dimensions in Phenotypically Double‐muscled Belgian Blue cows

Some anatomical characteristics of 507 Belgian Blue (BB) cattle, withers height (WH), heart girth (HG), the distance between the two tubera coxae (TcTc) and the distance between the two tubera ischiadica (TiTi), were compared with the internal pelvic measurements of width, height and area. Mean values were 58.9 ± 6.2 cm for TcTc, 14.6 ± 2.3 cm for TiTi, 15.2 ± 2.1 cm for pelvic width (PW), 18.8 ± 1.9 cm for pelvic height (PH) and 288.5 ± 60.9 cm(2) for pelvic area (PA). Cows that calved per vaginam had larger WH (p < 0.05), TcTc (p < 0.05) and TiTi (p < 0.001) and internal pelvic measurements [PH and PA (p < 0.001)] compared with those whose parturition was managed by caesarean section (CS): Correlations between internal pelvic measurements and TcTc were higher (r = 0.58-0.63) than TiTi (r = 0.22-0.28). Correlations between other external body measures such as HG and WH with the internal pelvic measurements were even higher for HG (r = 0.69-0.74) and for WH (r = 0.67-0.74). HG and WH, together with internal pelvic measures, may be added to estimated breeding values (EBV's) that should assist breeders in selecting cows that can calve per vaginam, thereby reducing the breed's dependence on elective CS for maintaining its unique characteristics.

Evaluation of discriminant analysis based on dorsoventral symmetry indices to quantify hindlimb lameness during over ground locomotion in the horse

Advances in gait analysis techniques have led to assessment tools that can aid in detecting and quantifying lameness; here, bilateral tubera coxae and pelvic movement during over ground locomotion are compared in order to investigate a practical method to assess hindlimb lameness in the horse. To evaluate which parameters from anatomical landmarks on trunk and proximal hindlimbs are the best indicators of degree and side of hindlimb lameness. Fifteen horses (age 11-23 years, 6 nonlame and 9 unilaterally hindlimb lame horses 1/10 to 2/10 lame) were fitted with 4 inertial sensors: tuber sacrale, left and right tubera coxae and withers; 889 strides were collected from 6 trot trials per horse. Horses were assessed for lameness by a qualified equine orthopaedic surgeon from videos. Vertical displacement data for each sensor were used to calculate symmetry indices as well as published Fourier analysis based parameters. Linear discriminant analysis was used to determine the most discriminative parameters for 2 scenarios: grading of severity of lameness and identification of the affected limb. Pelvic energy ratio gave the best indication for the degree of lameness. Directional symmetry index of the tubera coxae sensors yielded the highest discriminative power for identification of the lame limb. A good indication of the degree of hindlimb lameness can be obtained from vertical displacement data of the pelvic midline, collected from inertial sensors during over ground locomotion. The trunk mounted inertial sensor system allows for a time efficient collection of a representative database from horses with differing grade and site of lameness in a clinical setting. This is crucial for future work on a robust definition of the best parameters for lameness classification under practical conditions.

Three-dimensional kinematics of the equine spine during canter.

Most research on equine kinematics has previously been performed in the walking and/or trotting animal. This is also true for the few studies on the kinematics of the equine back. These studies have, for the major part, focused on the flexion-extension movement in the sagittal plane. However, vertebrae can rotate in 3 dimensions. This study was designed to determine all 3 rotations in various segments of the vertebral column of a cantering horse. Five Dutch Warmblood horses were measured during treadmill canter (7.3 m/s). Steinmann pins were inserted into the dorsal spinous processes of 8 thoracic (T), lumbar (L) and sacral (S) vertebrae and into both tubera coxae. A set of 4 markers was rigidly attached to each pin. The marker data were used to calculate a rotation matrix that was subsequently decomposed into 3 orthogonal rotations (flexion/extension [FE]; lateral bending [LB] and axial rotation [AR]). For the 3 rotations the variability between the horses was low for FE, slightly larger for AR and largest for LB. The maximal range of motion (mean +/- s.d.) for FE, LB and AR was 15.8 +/- 1.3 degrees, 5.2 +/- 0.7 degrees and 7.8 +/- 1.2 degrees, respectively. With respect to relative angles, the largest FE motion was found between L5 and S3 with values for the range of motion up to 8.6 degrees. Simultaneous rotation of successive vertebrae was observed particularly during the single support and suspension phases in the stride cycle, which increases spinal stability. For all rotations, a close correlation was observed between the timing of the vertebral rotations and the pro- and retraction of the limbs.

Kinematics of the hind limb in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and intra-articular administration of anesthetic.

To identify hind limb and pelvic kinematic variables that change in trotting horses after induced lameness of the distal intertarsal and tarsometatarsal joints and after subsequent intra-articular administration of anesthetic. 8 clinically normal adult horses. Kinematic measurements were made before and after transient endotoxin-induced lameness of the distal intertarsal and tarsometatarsal joints and after intra-articular administration of anesthetic. Fourteen displacement and joint angle (metatarsophalangeal [fetlock] and tarsal joints) measurements were made on the right hind limb, sacrum, and the right and left tubera coxae. Kinematic measurements were compared by general linear models, using a repeated measures ANOVA. Post hoc multiple comparisons between treatments were evaluated with a Fisher least squared difference test at alpha = 0.05. After lameness induction, fetlock and tarsal joint extension during stance decreased, fetlock joint flexion and hoof height during swing increased, limb protraction decreased, and vertical excursion of the tubera coxae became more asymmetric. After intra-articular administration of anesthetic, limb protraction returned to the degree seen before lameness, and vertical excursion of the tubera coxae became more symmetric. Increased length of hind limb protraction and symmetry of tubera coxae vertical excursion are sensitive indicators of improvement in tarsal joint lameness. When evaluating changes in tarsal joint lameness, evaluating the horse from the side (to assess limb protraction) is as important as evaluating from the rear (to assess pelvic symmetry).

The pattern of healing following implantation of heterogenous anorganic compact bone in sheep

Bovine cortical ethylenediamine extracted (anorganic) bone was implanted into surgically created defects in the long bones and tubera coxae of sheep. In some defects the anorganic bone was implanted as a block, in others the material was fragmented and passed through a 15 mesh/in, sieve, and control defects were allowed to fill with blood. The sites of the defects were studied histologically after periods ranging from 14 to 392 days. The blocks of anorganic cortical bone were revascularized, and new bone formed both on the outer surfaces and within the vascular canals. Thereafter, the material showed little change, and even after more than a year the greater part of the implant remained. Fragmented anorganic bone became more intimately incorporated in the new host bone, but the fragments were still present over a year after implantation. There was no evidence of foreign body reaction, or of osteoclastic resorption; the anorganic bone appeared to act as an inert foreign body. When implanted into a naturally osteogenic site, as in these experiments, the material tended to impede healing. However, there was evidence that either form of implant prevented the herniation of the bone marrow which appeared to be the cause of imperfect healing in some control defects.