Eleonora Pagliara

Orthotics are often used to support the metacarpophalangeal joint (MCPj) in horses recovering from soft tissue injury; however, their effect on the MCPj biomechanics remain largely underexplored. The MCPj moves primarily in the sagittal plane, flexing during the swing phase and extending during the stance phase. The suspensory ligament and flexor tendons act as biological springs resisting MCPj extension. Injuries to these structures are common and, although early mobilization promotes their healing, controlled loading may be beneficial during rehabilitation. This study aims to evaluate the efficacy of a semirigid orthotic in limiting the MCPj extension and the MCPj range of motion, and its influence on the MCPj kinematics. Twelve healthy horses were equipped with portable inertial sensors on the distal limb. The MCPj extension and the MCPj range of motion were assessed during walking and trotting without the orthotic (S0) and with the orthotic using two different support settings (S1 and S4). Data were evaluated for normality and homoscedasticity. A Student t-test was used to compare the MCPj angle pattern of the two forelimbs of each horse at the baseline. Data were analysed using one-way ANOVA to compare the mean values across conditions, followed by paired t-tests for post-hoc comparison (significance set at p < 0.05). The results showed significant reductions in both the MCPj extension and the MCPj range of motion, with the greatest restriction occurring at the highest support setting. These results suggest that the semirigid orthotic limits the MCPj movement in the sagittal plane and consequently the load on the suspensory ligament and flexor tendons. Therefore, this orthotic device is an effective tool during rehabilitation for forelimb tendon and ligament injuries.

Obtaining a healthy wound environment that is conductive to healing in horses can be challenging. Negative-pressure wound therapy (NPWT) has been employed in humans to enhance wound healing for decades. The existing evidence for the effectiveness of NPWT remains uncertain in equine medicine. The aim of this review is to investigate NPWT applications and benefits in horses. A scoping review was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines for scoping reviews on three databases (PubMed, Web of Science-Thompson Reuters, and Wiley Online Library). Twenty-four manuscripts were considered. After removing duplicates, 17 papers underwent abstract screening. Of these, 16 + 1 (cited by others) were evaluated for eligibility according to PICOs, including no case reports/retrospective studies, four original articles, and three reviews. Fifteen manuscripts met the inclusion criteria. The focus of the articles was wound management; they included three reports of wounds communicating with synovial structures. Traumatic wounds and surgical-site infections are indications for NPWT. NPWT presents several advantages and few complications making it an attractive alternative to conventional wound management. However, randomized controlled trials should be performed to quantify the benefits and establish precise protocols in horses.

Fetlock joint angle (FJA) pattern is a sensitive indicator of lameness. The first aim of this study is to describe a network of inertial measurement units system (IMUs) for quantifying FJA simultaneously in all limbs. The second aim is to evaluate the accuracy of IMUs for quantifying the sagittal plane FJA overground in comparison to bi-dimensional (2-D) optical motion capture (OMC). 14 horses (7 free from lameness and 7 lame) were enrolled and analyzed with both systems at walk and trot on a firm surface. All enrolled horses were instrumented with 8 IMUs (a pair for each limb) positioned at the dorsal aspect of the metacarpal/metatarsal bone and pastern and acquiring data at 200 Hz. Passive markers were glued on the center of rotation of carpus/tarsus, fetlock, and distal interphalangeal joint, and video footages were captured at 60 Hz and digitalized for OMC acquisition. The IMU system accuracy was reported as Root Mean Square Error (RMSE) and Pearson Correlation Coefficient (PCC). The Granger Causality Test (GCT) and the Bland–Altman analysis were computed between the IMUs and OMC patterns to determine the agreement between the two systems. The proposed IMU system was able to provide FJAs in all limbs using a patented method for sensor calibration and related algorithms. Fetlock joint range of motion (FJROM) variability of three consecutive strides was analyzed in the population through 3-way ANOVA. FJA patterns quantified by IMUs demonstrated high accuracy at the walk (RMSE 8.23° ± 3.74°; PCC 0.95 ± 0.03) and trot (RMSE 9.44° ± 3.96°; PCC 0.96 ± 0.02) on both sound (RMSE 7.91° ± 3.19°; PCC 0.97 ± 0.03) and lame horses (RMSE 9.78° ± 4.33°; PCC 0.95 ± 0.03). The two systems’ measurements agreed (mean bias around 0) and produced patterns that were in temporal agreement in 97.33% of the cases (p < 0.01). The main source of variability between left and right FJROM in the population was the presence of lameness (p < 0.0001) and accounted for 28.46% of this total variation. IMUs system accurately quantified sagittal plane FJA at walk and trot in both sound and lame horses.

A catastrophic fracture of the radial carpal bone experienced by a racehorse during a Palio race was analyzed. Computational modelling of the carpal joint at the point of failure informed by live data was generated using a multibody code for dynamics simulation. The circuit design in a turn, the speed of the animal and the surface characteristics were considered in the model. A macroscopic examination of the cartilage, micro-CT and histology were performed on the radio-carpal joint of the limb that sustained the fracture. The model predicted the points of contact forces generated at the level of the radio-carpal joint where the fracture occurred. Articular surfaces of the distal radius, together with the proximal articular surface of small carpal bones, exhibited diffuse wear lines, erosions of the articular cartilage and subchondral bone exposure. Even though the data in this study originated from a single fracture and further work will be required to validate this approach, this study highlights the potential correlation between elevated impact forces generated at the level of contact surfaces of the carpal joint during a turn and cartilage breakdown in the absence of pre-existing pathology. Computer modelling resulted in a useful tool to inversely calculate internal forces generated during specific conditions that cannot be reproduced in-vivo because of ethical concerns.

Summary: The objective of this study was to describe lateral patellar instability (LPI) in a population of weanling Standardbreds and characterise the prevalence, clinical features, imaging findings and long‐term follow‐up. A total of 222 weanling Standardbreds were examined between June 2017 and December 2019 for presales examination, and LPI was identified in four horses. Presumptive diagnosis was made on clinical and dynamic examination at walk and confirmed by radiography. One horse was subject to euthanasia for causes related to LPI (Case 3), and computed tomography (CT) of both hindlimbs was performed post‐mortem in order to better characterise the anatomical variations of the affected stifle. The intertrochlear groove angle (IGA), the angle of anteversion (AA) of the femoral neck, the anatomical lateral distal femoral angle (aLDFA) and the degree of tibial torsion (TT) were measured. LPI prevalence in Standardbreds weanlings was 1.8%, and it carried a poor athletic prognosis. Radiographic abnormalities were observed in the shape of the patella, characterised by a rounder profile and a less pronounced sagittal crest. The abnormal limb also presented a wider IGA, an outward rotation of the proximal aspect of the tibia and varus deformity of the femorotibial joint compared with the contralateral limb. LPI seems to occur with a high prevalence in the Standardbred weanling population, and our findings suggest that LPI is related to a combination of epiphyseal dysplasia and rotational and angular abnormalities of the affected limb. No effective treatments have been reported.

Objectives This article evaluates and compares the diffusion pattern of radiopaque contrast medium following perineural analgesia of the deep branch of the lateral plantar nerve performed using two different techniques: weight-bearing or flexed. Study Design This was an in vivo experimental study. Methods Eight horses were enrolled. Perineural injection of the right and left deep branch lateral plantar nerves was performed with a weight-bearing or flexed technique, using radiopaque contrast medium (iohexol). Radiographic evaluation was performed after 5 (T5), 15 (T15) and 30 (T30) minutes. The diffusion of contrast medium was assessed independently by two blinded readers who analysed the extension of the main contrast medium bulk and the maximum diffusion of contrast medium in both proximal and distal directions. The effect of time and technique employed on contrast medium diffusion was assessed using two-way analysis of variance for repeated measures (p ≤ 0.05). Results There was no significant difference in the diffusion of the contrast medium between the two techniques at T15. However, at T30 the weight-bearing technique resulted in a significantly increased diffusion in the proximal direction (p = 0.02). In one case, belonging to the weight-bearing group, contrast medium was identified within the tarsal sheath. There was no evidence of contrast medium in the tarsometatarsal joint of any horse, regardless of the technique used. Conclusions The two techniques resulted in a similar diffusion at T15. However, the use of a weight-bearing technique resulted in a significant increase in proximal contrast medium diffusion 30 minutes after injection.

Summary: Background: Information on interference injuries in racehorses is lacking. Objective: To describe clinical findings and prognosis of palmar forelimb interference injuries in Standardbreds. Study design: Retrospective cohort study. Methods: Records of 74 racehorses sustaining palmar forelimb interference injuries were studied; 7 occurred during training and 67 during racing. The number of starts before injury, hind shoeing status, gait penalties and racing speeds in cases occurring during racing were compared with negative controls (67 age, sex and speed category matched horses) from the same races. The number of starts and racing speed in 30 racing days preceding recruitment were compared with those following recruitment (negative controls) or return to racing (cases). Clinical aspects and outcome in interference‐induced superficial digital flexor (SDF) tendonitis were compared with 77 horses with overstrain‐induced SDF tendonitis. Results: In 89% of cases, there was SDF tendonitis and this was associated with a longer time to return to racing (6 months vs. 1 months; Pper racing day, interquartile range [IQR] 20–32) compared with controls (49, IQR 43–55, P<0.0001). Interference‐induced tendonitis cases (n = 58) had a shorter time to return to racing (245 ± 137 days) than overstrain‐induced tendonitis cases (331 ± 118 days, P<0.001). Main limitations: Data were collected retrospectively; time of ultrasonographic assessment varied and health status of the racing controls is unknown. Conclusions: SDF tendonitis is common with palmar forelimb interference injuries in Standardbreds and increases time to return to racing. Interference‐induced SDF tendonitis has a better prognosis than overstrain‐induced tendonitis.