Lateromedial Radiographs Research Articles

Arthroscopic visualisation of the third metacarpal and metatarsal condyles in the horse

Arthroscopy of the fetlock joints is a routine surgical procedure in the horse. It is unclear how much of the articular surface of the condyles of the metacarpal (MCIII)/metatarsal (MTIII) bone can be visualised using either the dorsal or palmar/plantar arthroscopic approach. To investigate which part of the articular surface of the MCIII/MTIII condyles of the fetlock joints can be evaluated arthroscopically using: 1) dorsal approach in combination with flexion; 2) standard palmar/plantar approach; or 3) additional portal at the base of the sesamoid bone with joint extension. All 3 arthroscopic approaches were performed on 20 fore- and 20 hindlimbs of 14 cadavers. For each approach, a curette was inserted ipsilaterally to create a lesion at the most distal part of the condyle that could be seen. After disarticulation and placement of a nail in each lesion, the maximally reachable angle was calculated on a perfect lateromedial radiograph. The 0 degrees angle was determined as the distal crossing of the best fitting circle around the condyle with a line parallel to the dorsal MCIII/MTIII bone running through the circle centre (positive angle dorsal to 0 degrees, negative palmar/plantar to 0 degrees). Using the dorsal approach with flexion, a significantly larger area of visualisation was present in the hind- (-23.4 degrees) compared to the forelimb (+2.7 degrees). Using the palmar/plantar approach (fore: -60.4 degrees; hind: -70.7 degrees) and the approach at the base of the sesamoid bone (fore: -36.3 degrees; hind: -47.6 degrees) more cartilage could be seen in the fore- compared to the hindlimb. When combining the 3 approaches, the remaining nonvisible part measured 38.9 degrees in the fore- and 24.2 degrees in the hindlimb, both located palmaro/plantarodistally. The use of dorsal and palmar/plantar arthroscopic approaches in combination with flexion and extension of the fetlock joint allows visualisation of the majority of the cartilage of the MCIII/MTIII condyles. The nonvisible section is smaller in the hindlimb compared to the forelimb. Knowledge of the specific areas of visualisation of the condyles on arthroscopy is important for both diagnostic and therapeutic planning of fetlock disorders.

Diagnostic accuracy of digital photography and image analysis for the measurement of foot conformation in the horse

Rigorous evaluation of practicable methods for the objective assessment of foot conformation has not been performed. To assess the practicability, precision and accuracy of the process of obtaining measurements of horses' feet using photography and image processing software. Precision study: Lateral photographs of horses' feet were obtained twice by 2 veterinary surgeons (image acquisition - IAc). Photographs were analysed by 2 masked veterinary surgeons on 2 occasions (image analysis - IAn). Measurements were compared within and between operators for self and non-self acquired photographs. Agreement indices (AIs) and 95% limits of agreement (LOA) were calculated for the IAn process alone and for the combined IAc + IAn processes. Accuracy study: Measurements obtained from lateral photographs were compared with those obtained from lateromedial radiographs. AIs and 95% LOA were calculated for each measurement. Precision study: Mean intra- and interoperator AIs for the IAn process alone were > or = 0.90 while those for the combined IAc + IAn processes were > or = 0.89 for all measurements. Similar mean AIs and 95% LOA were calculated regardless of image origin. The 95% LOA for hoof angle, heel height/toe height% and coronary band angle for all comparisons were within target values. Accuracy study: Mean AIs were > or = 0.89 for all measurements. The 95% LOA for heel height/toe height% and coronary band angle were within target values. Excellent precision was identified within and between operators regardless of image origin. High levels of accuracy were also identified, especially for heel height/toe height% and coronary band angle, indicating that photography and radiography may be used interchangeably. Acquisition and analysis of photographic images is an appropriate method for the objective measurement of foot conformation, both in clinical and, research settings.

Scapulohumeral osteochondrosis

To review the outcome of equine shoulder osteochondrosis (OC) with surgical or conservative treatment. Retrospective study of 32 horses, less than two years of age, with scapulohumeral joint (SHJ) OC. The lesion severity was graded based on measurements taken from lateromedial radiographs. Follow-up information was obtained from racing records or telephone conversations with owners. Successful outcome was defined as the ability of the horse to perform its intended use. Sixteen of 32 horses were affected bilaterally (48 joints). Eleven of 16 horses with bilateral OC underwent arthroscopic surgery; five had bilateral arthroscopy, six had unilateral arthroscopy of the most severely affected joint. Eight of 16 horses with unilateral OC underwent arthroscopy. The overall outcome was 'poor'. Only 15.4% (4/26) of potential race horses started a race, whereas 67% (4/6) non-racehorses were 'sound' for the intended use. Statistical analysis evaluating the effect of breed on outcome showed a statistically significant difference. There were no significant interactions between outcome and gender, affected limb, unilateral versus bilateral involvement, treatment or severity of the radiographic lesion. However, radiographic lesion severity on the humerus and glenoid showed significant positive correlation. The overall poor prognosis for shoulder OC in young horses appears to be, in part, dependent on breed and intended use. There was not any difference in outcome between surgically and conservatively treated horses.

Valores normais da densidade mineral óssea do acessório do carpo em eqüinos da raça Brasileiro de Hipismo (BH) determinados por meio da densitometria óptica em imagem radiográfica

Com o objetivo de estabelecer os valores normais da densidade mineral óssea (DMO) em milímetros de alumínio (mmAl) de eqüinos da raça Brasileiro de Hipismo (BH), foi radiografado o osso acessório do carpo de animais desta raça e aplicada a técnica da densitometria óptica em imagem radiográfica (DOR). Foram utilizados animais de 20 a 30 meses de idade, sendo 12 machos e 12 fêmeas. A DMO média foi de 4,7 ± 0,1mmAl para os machos e de 4,6 ± 0,1mmAl para as fêmeas, não sendo significativa a diferença entre estes valores.

Avaliação da densidade mineral óssea em potros da raça Puro Sangue Inglês em início de treinamento

The Radiographic Optical Densitometry (ROD) is an analysis method for bone mineral content evaluation in equivalence to the aluminiun milimeters (mmAI). Bone densitometry was performed by a carpal acessory bone simple latero-medial radiograph conjugated with an aluminium stepwedge after complete calcification of growth plate of radial distal epifisis. Two groups (divided by sexual category male/female) of 50 animals each were evaluated and all these 100 animals were under an initial trainning program during the experiment. Radiographs were digitalized and analyzed by a specific software (Imagelab, Softium) responsible for bone densitometry final determination expressed in mmAI. Statistical analysis (Instat) was performed on results for determination of normal curve of bone density by ROD method.

Ultrasonography of the solar aspect of the distal phalanx in the horse.

Ultrasonographic examinations were performed on the solar aspect of the distal phalanx of 10 feet of five normal live horses (Group 1), 22 feet of seven normal cadavers (Group 2), and nine feet of five horses with pathology of the dorsal solar aspect of the distal phalanx (Group 3). Lateromedial radiographs of the distal phalanx were made in all groups, and in Group 2, digits were sagitally sectioned after imaging. The ultrasonographic and radiographic appearance of the sagittal solar aspect of the distal phalanx was described. Measurements of the distance between the sole and the distal tip of the distal phalanx (A), the solar aspect of the apex of the frog and the distal phalanx (B), and the body of the frog's surface and flexor surface of the distal sesamoid bone (C) were made ultrasonographically, radiographically, and on the sectioned cadaver specimens. There was no statistical difference between the radiographic, ultrasonographic, and direct cadaver measurements in A and C. In B, there was a statistical difference between the radiographic, ultrasonographic, and cadaver measurements-most likely as a result of the difference in trimming of the frog apex. Ultrasonographic and radiographic examination of the nine feet of the five horses in Group 3 were performed and the abnormalities described. Color flow and power Doppler ultrasonography were performed on the normal sagittal solar distal phalanx, on the impar distal sesamoidean ligament, and at the insertion of the deep digital flexor tendon on the facies flexoria of the distal phalanx. Power Doppler in these horses showed blood flow at 0.16-0.48 kHz at the tip of the distal phalanx and at 0.16 kHz at the deep digital flexor tendon insertion and in the impar distal sesamoidean ligament. Using color flow Doppler in normal horses mean blood flows ranged from 1.8 to 5.4 cm/s at the tip of the distal phalanx and 1.8-2.0 cm/s at the deep digital flexor tendon insertion and in the impar distal sesamoidean ligament.

Evaluating the measuring software package Metron-PX for morphometric description of equine hoof radiographs

Abstract Reasons for performing the study Radiography is still the most common diagnostic tool to assess hoof injury in horses. Radiologic measurements are important in the evaluation of the quality of hoof trimming or displacement of the pedal bone in laminitic hooves. A specific program called Metron-PX was designed to measure distances and angles in the hoof. The purpose of this study was to determine the exactness of the radiologic measurements obtained with this program. Design In vitro, experimental study. Procedure Evaluation of the software Metron-PX was based on 88 radiographs taken of 2 forelimbs of 2 orthopedically sound horses that were humanely euthanized for reasons unrelated to this study. In a total of 33 parameters obtained from the dorsopalmar and lateromedial radiographs, the effect caused by repeated measurements of the same digitalized radiograph in 2 magnifications, the radiographic technique, and different operators was evaluated. On the lateromedial radiograph, these measurements were compared with the corresponding sagittal section of the anatomic specimens (anatomic standard). Results Statistically significant differences were seen among the measurements obtained of the 33 parameters in the 4 different tests. These differences correspond to the low values of the variation coefficient of the measurements taken in each test and the difficulty of cutting the foot precisely in the sagittal plane that coincides with the radiographic projection. Conclusions and clinical relevance Even though there are differences among the measurements in the 4 tests, most of them are not considered clinically relevant. The radiographic technique and the Metron-PX software can be used to objectively measure most of the parameters predefined by the software.

Short-duration exercise and confinement alters bone mineral content and shape in weanling horses

The hypothesis that short-duration exercise may ameliorate the decrease in bone mass observed with confinement was investigated with 18 quarter horses (nine colts and nine fillies) weaned at 4 mo of age and placed into box stalls. After a 5-wk adjustment period, individuals were grouped by age and weight, and then divided randomly into three treatment groups: 1) group housed; 2) confined with no exercise; and 3) confined with exercise. The confined and exercised groups were housed in 3.7 m x 3.7 m box stalls for the 56-d duration of the trial. The exercised group was sprinted 82 m/d, 5 d/wk, in a fenced grass alleyway. The weanlings were led down an alleyway, turned loose in a small pen, and then released and allowed to run back down the alley. The group horses were housed together in a 992-m2 drylot with free access to exercise. On d 0, 28, and 56, dorsopalmar and lateromedial radiographs of the left third metacarpal bone were taken to estimate changes in bone mineral content and cortical widths. Mean values of medial, lateral, and total radiographic bone aluminum equivalence increased over time (P < 0.05), whereas dorsal and palmar radiographic bone aluminum equivalence did not change significantly. Dorsal, medial, and total radiographic bone aluminum equivalence tended (P = 0.09) to differ by a treatment x day interaction, with values increasing over time only in the exercised group. Normalized medial and total radiographic bone aluminum equivalence tended (P < 0.1) to differ (P < 0.01) with treatment, with exercised horses having greater bone aluminum equivalence than confined horses. Dorsopalmar cortical width in exercised horses was greater than on d 56 (treatment x day; P = 0.07). The dorsopalmar medullary cavity decreased in exercised vs. group-housed horses (P = 0.027), whereas dorsal and medial cortical width tended to increase only in the exercised horses (treatment x day; P < 0.01). This study indicated that a short-duration exercise protocol might be effective in improving bone mass and therefore skeletal strength in horses.

Relationship of foot conformation and force applied to the navicular bone of sound horses at the trot.

Collapsed heels conformation has been implicated as causing radical biomechanical alterations, predisposing horses to navicular disease. However, the correlation between hoof conformation and the forces exerted on the navicular bone has not been documented. The angle of the distal phalanx in relation to the ground is correlated to the degree of heel collapse and foot conformation is correlated to the compressive force exerted by the deep digital flexor tendon on the navicular bone. Thirty-one shod Irish Draught-cross type horses in routine work and farriery care were trotted over a forceplate, with 3-dimensional (3D) motion analysis system. A lateromedial radiograph of the right fore foot was obtained for each horse, and various measurements taken. Correlation coefficients were determined between hoof conformation measurements and between each of these and the force parameters at the beginning (15%) of stance phase, the middle of stance (50%) and at the beginning of breakover (86% of stance phase). Significance was defined as P<0.05. The force exerted on the navicular bone was negatively correlated (P<0.05) to the angle of the distal phalanx to the ground and to the ratio between heel and toe height. This was attributed to a smaller extending moment at the distal interphalangeal joint. There was not a significant correlation between the angle of the distal phalanx and the degree of heel collapse, and heel collapse was not significantly correlated to any of the force parameters. Hoof conformation has a marked correlation to the forces applied to the equine foot. Heel collapse, as defined by the change in heel angle in relation to toe angle, appears to be an inaccurate parameter. The forces applied on the foot are well correlated to the changes in the ratio of heel to toe heights and the angles of the distal phalanx. Assessment of hoof conformation should be judged based on these parameters, as they may have clinical significance, whereas parallelism of the heel and toe is of less importance.

Effects of heel and toe elevation upon the digital joint angles in the standing horse.

Five sound mature horses, age 8-14 years, with toe angles 45.5-55.0 degrees were placed on a specially designed platform with only the left forelimb weightbearing, which allowed the successive production of 7 different conditions of foot orientation: neutral position (N), 5, 10, 15 degrees heel (H5, H10, H15) and toe (T5, T10, T15) elevation, performed according to 2 different sequences. For each condition, 2 lateromedial radiographs were taken to evaluate the metacarpophalangeal joint (MPJ) and both interphalangeal joint (PIPJ and DIPJ) angles, respectively. In addition, two-dimensional (2-D) kinematic recordings, using reflective skin markers placed laterally on the left forelimb joints, were performed. The value of each joint angle (JA) and its angular variation to N (AV) were considered for statistical analysis. For all JA and their AV determined radiographically, the condition effect was significant and the sequence did not influence the differences between conditions. The relationships between the JA and the conditions (in the sequence: T15, T10, T5, N, H5, H10, H15) were overall linear for the 3 joints. The maximal range T15-H15 was mean +/- s.d. 6.9 +/- 2.0 degrees for MPJ (dorsal angle decrease), 7.3 +/- 1.0 degrees and 29.5 +/- 1.8 degrees for PIPJ and DIPJ (palmar angle decrease), respectively. Contrary to JA and in spite of large variations in hoof conformation, AV did not show any significant horse effect. Wide differences were observed between the digital JA measured radiographically and from kinematics, which could be related to cutaneous displacement. Heel elevation induced elbow flexion, whereas a slight extension was observed with toe elevation. These movements, even slight (mean elbow angle amplitude: 3.6 +/- 1.3 degrees), may have consequences upon flexor tendon tension.

Morphometric and mechanical properties of femora in young adult male turkeys with and without femoral fractures

Morphologic and torsional mechanical properties of femora were evaluated in three groups of turkeys to determine whether turkeys that incurred femoral fracture have different radiographic, morphologic, and torsional mechanical properties than do turkeys without femoral fracture, and if body weight was a factor differentiating affected and nonaffected turkeys. Nine turkeys with unilateral femoral fractures and nine turkeys without fractures from Farm A were compared with a group of nine age and genetically matched turkeys from Farm B. Turkeys from Farm A were 10 to 25% heavier (26.2+/-0.9 kg) and turkeys from Farm B were 10% lighter (18.2+/-0.9 kg) than expected breed standards. Femoral length, cortical thickness, medullary diameter, and diaphyseal curvature were measured from craniocaudal and lateromedial radiographs. One intact femur from each of five turkeys with a contralateral femoral fracture (Farm A), nine unaffected turkeys from Farm A, and nine turkeys from Farm B were subjected to failure in a torsion test. Geometric and mechanical results were compared. Turkeys from Farm A had a thicker cortex and a smaller medullary diameter than turkeys from Farm B. Turkeys from Farm A had significantly lower torsional stiffness and failure torque values compared with turkeys from Farm B, when differences in body weight were accounted for (analysis of covariance, P < 0.05). Mechanical failure torque calculated from geometric values suggests that organic or inorganic material arrangement and composition may be responsible, in part, for differences between groups. Femoral fractures may be associated with insufficient skeletal adaptation to heavy body weight.

RADIOGRAPHIC APPEARANCE OF THE EQUINE STIFLE FROM BIRTH TO 6 MONTHS

Lateromedial radiographs of 74 stifles from foals with no stifle swelling or lameness were evaluated to determine the range of normal variation. Foals ranged in age from 0 to 25 weeks with approximately one half of the foals being younger than 11 weeks of age. Nine breeds were represented, with Standardbred and Quarter horse being the most common. Femoral trochlear ridges and patellas were graded on a scale of 1–4 from regular and well defined (1) to very irregular (4). Femoral and tibial condyles were evaluated for irregularity. Twelve stifles were evaluated at necropsy. Irregular to very irregular patellas and trochlear ridges were found in foals up to 20 weeks of age. In foals younger than 11 weeks of age, 77% of bone borders were irregular or very irregular, whereas only 23% of bone borders from foals 11–25 weeks of age had irregular borders. A grade of very irregular was found in 33% of bone borders of foals younger than 11 weeks old, whereas only 1.25% of bone borders of older foals were graded very irregular. Asymmetry in the bone borders between left and right stifle was evident in 36% of the studies, but did not vary by more than one grade. Femoral and tibial condyles were nearly all regular and well defined regardless of age. These findings suggest that obvious irregularities of the femoral or tibial condyles in foals should be interpreted as pathologic. Patellas and trochlear ridges were ranked smooth in 3% of foals younger than 11 weeks of age and in 55% of bone borders of foals 11–25 weeks of age. Obvious irregularities of the patellas or femoral trochlear ridges may be well within normal limits in foals younger than 5 months. Consistent and diagnostic radiographic studies can be obtained safely in most standing foals with little or no sedation.

RADIOGRAPHIC EVALUATION OF THE PALMAR ASPECT OF THE EQUINEMETACARPAL CONDYLES: A NEW PROJECTION*

A New radiographic projection of the equine thrid metacarpal bone condyles and developed to aid detection and evaluation of ulcerative cartilaginous and osseous lesions on the MC III Papmar aspect. The most sccessful projection tried was a nonweight‐bearing one with the leg extended. Subsequent clinical evaluation proved this projection to be significant in confirming and further delineating palmar lesions seen on weight‐bearing lateromedial and flexed lateromedial radiographs. The new projection has also proved valuable in the complete evaluation of vertical MC III condylar fractures. It makes possible detection of fracture comminution at the condylar articular surface, fractures which cannot be seen on other projections.