Objective: Metacarpophalangeal joint (MCPJ) radiographic parameters were developed to evaluate MCPJ conformation of equine forelimbs, but the effect of joint rotation during radiography on these parameters has not been reported. The current study examined the effect of the rotation around the vertical axis of MCPJ on 27 MCPJ parameters (12 angles and 15 ratios) and identified the acceptable range of rotation at which minimal amount of changes occurred in these parameters. Design: Descriptive study Animals: MCPJs of seven right forelimbs from seven different horses with no MCPJ abnormalities. Procedures: MCPJs of seven right equine forelimbs were loaded in a load cell to obtain the normal MCPJ angle. They were frozen at −20C° and then scanned using a CT-scan machine. The collected slices were reconstructed to obtain a 3D model of MCPJs, and the dorsopalmar view at zero angle (ZDP) were identified. The view was then rotated around the vertical axis of MCPJ. Snapshots were taken for MCPJ at −10°, −5°, Zero, +5° and +10° angles. All the parameters were measured on the total 35 radiographs and statistically analysed. Differences were estimated per 5° of MCPJ rotation for all the parameters. Results:Generally, the ratio parameters were less affected than the angular parameters during MCPJ rotation. Conclusion and clinical relevance: Rotational angles of vertical ±10° from ZDP were considered as an acceptable range for reliable radiographic measurements of MCPJ parameters. Keywords Equine; fetlock; morphometry; radiology; rotation
Abdulrhman Mohamed Salah Alrtib, Aiman Hussein Saleh Oheida, Mohamed Hamrouni S. Abushhiwa, Helen M.S. Davies(12-2021)

Relationships between carpal morphology and carpal pathology might assist in identifying horses at risk of carpal pathology. This study was aimed to investigate the hypothesis that carpal morphology is related to the incidence of carpal pathology in racing Thoroughbreds. Ten carpal parameters were used to measure carpal morphology on dorsopalmar (DP) carpal radiographs. Radiographs were collected from 19 experienced Thoroughbred race horses with no evidence of carpal damage(normal)and 72 horses with carpal damage (clinical). All radiographs were at a defined position called zero degrees (ZDP) or within an acceptable rotational range. Based on a P-value of < 0.05 and using the false discovery rate method to control Type I error, two parameters showed significant differences between normal and clinical horses. The angulation of the radial metaphysis and distal radius in relation to the angulation of the radial facet of the third carpal bone (C3) was significantly related to the occurrence of pathology in the bones of the middle carpal joint in Thoroughbred race horses. This study presented important features on DP radiographs that allowed identification of a carpal conformation associated with carpal damage in Thoroughbred race horses. Using such a highly specific, cost-effective and safe technique as a routine for examining yearling Thoroughbreds would assist in identifying horses with carpal conformation unsuited to racing.
Aiman Hussein Saleh Oheida, Abdulrhman Mohamed Salah Alrtib, Mohamed Hamrouni S. Abushhiwa, Christopher J. Philip, Helen M.S. Davies(1-2022)

Several reports have discussed possible bony morphological causes of fetlock pathology but without relating them to its morphometry. Radiographic measurement is widely used in constructing numerical databases of bone morphometry. Such measurements would not be reliable unless all factors affecting the radiographs were considered. Therefore, this study aimed to establish a specific dorsopalmar view (DP) for fetlock radiographic measurements, and then to develop reliable and repeatable fetlock parameters that represent fetlock conformation on those DP radiographs. Ten cadaveric forelimbs from ten adult horses were cut at the distal third of the radius and mounted in a normal posture for DP radiography. Specific features on fetlock bones were used as landmarks to identify the DP at zero degrees. Other bony features were selected as landmarks for developing fetlock parameters on these radiographs. Twenty-seven parameters were designed in the form of angles (12) and ratios (15). The repeatability and consistency of each parameter was tested. A specific fetlock DP view was determined at zero degrees based on certain landmarks. All angular and ratio parameters showed high reliability and consistency in their measurements. The established parameters provide an opportunity to test the relationship between fetlock morphometrics and performance, or the likelihood of certain pathologies.
Abdulrhman Mohamed Salah Alrtib, Aiman Hussein Saleh Oheida, Mohamed Hamrouni S. Abushhiwa, Helen M S Davies(3-2019)