Front fetlock joint angle (FA) measurement might predict musculoskeletal injury. This study aimed to identify an accurate reliable tool, and develop a consistent method for measuring the FA. Fetlock centre of rotation was identified radiographically. Goniometer measurements were validated on ten vertically fixed post-mortem distal forelimbs by positioning the centre of rotation of the goniometer on the approximate centre of rotation of the joint for five measurements of each FA at three day intervals and one measurement by another person (rater B). Both FA’s of fourteen sound horses standing squarely on a concrete floor were repeated before and after lifting the contralateral limb, which was flexed at the carpus and held at the same level as the carpus of the standing limb. Consistency of measurements was assessed using both fetlock joints of five horses standing squarely on a concrete floor measured six times in random order and then with the contralateral limb lifted using both front fetlocks of eight horses measured five times in random order. The repeatability coefficient was calculated with WinPepi v10.5 software. The centre of rotation was on or around the eminence of the lateral collateral ligament. The repeatability coefficient of the goniometer validation was 4.7°. The mean FA for rater A and B were not significantly different (161.4° versus 162.9°). FA’s were significantly less after lifting the contralateral limbs (P
Abdulrhman M. Alrtib, Helen M S Davies(7-2012)

There are many reports describing fractures in the bony elements of the equine fetlock joint and a few of these discuss possible relationships of these fractures to the mechanical loading of these bones. The likelihood of fracture must be related to the size and shape of bones involved, but information concerning the normal range in size and shape of these bones in horses is lacking. This study aimed to identify morphometrical variations of these bones within different groups of horses. Right and left metacarpal, proximal phalangeal and proximal sesamoid bones were collected from 10 Thoroughbreds (TB), five Standardbreds (SB) and eight Ponies (P) euthanized for non-orthopaedic reasons. All bones were boiled, cleaned and dried. Dimensional parameters were measured using a custom-built apparatus, calliper and plastic tape. The width and depth of the medial condyles of Mc3 were greater than the lateral condyles in all groups. The length to the lateral condyle was greater than the length to the medial condyle of Mc3, and the lengths of the lateral sides of the Mc3 and P1 bones were greater than the lengths of the medial sides in both forelimbs of all groups. The lateral sesamoids were similar to, or larger than, the medial sesamoids in all dimensions. There were some morphometrical variations in the bony elements of the equine fetlock joints in all groups.
Abdulrhman Mohamed Salah Alrtib, C J Philip, Aiman Hussein Saleh Oheida, Helen M S Davies(4-2012)

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)