Novel computed tomographic analysis demonstrates differences in patterns of bone mineral content between fracture configurations in distal condylar fractures of the third metacarpal/metatarsal bones in 97 Thoroughbred racehorses.

OBJECTIVE: To evaluate bone mineral content patterns between fracture configurations using novel CT image analysis. ANIMALS: CT images from 97 Thoroughbred racehorses with third metacarpal/tarsal condyle fractures provide the case population for analysis. PROCEDURES: Fractures were grouped by radiographic appearance. Image analysis objectively measured area of highly attenuating pixels (aHAP), areal density of highly attenuating pixels (dHAP) utilizing novel convex hull analysis, and subjective assessment of apparent attenuation intensity ranking (AAIR) for each fracture. Differences between fracture configuration groups were evaluated. RESULTS: Analysis of dHAP identified lower-density regions of highly attenuating pixels in propagating fractures and higher-density regions of highly attenuating pixels in unicortical fractures (P = .028). Complete and incomplete configurations were almost indistinguishable in dHAP (P = 1.000). The ratio of dHAP between fractured and nonfractured condyles revealed higher density gradients between condyles in unicortical (P = .040) and incomplete (P = .031) fractures than propagating fractures. CLINICAL RELEVANCE: Differences in patterns of bone mineral content were identified between propagating, bicortical (incomplete and complete), and unicortical fractures of third metacarpal/tarsal bone condyles. Computer-assisted geometric measurement of dHAP identified on CT images could help to assess fracture risk in equine athletes. This application may have greater relevance as standing CT screening becomes more available.

Intermediate patellar ligament desmopathy often occurs in conjunction with other stifle abnormalities.

Intermediate patellar ligament (IPL) desmopathy is a relatively uncommon injury previously reported to have a poor prognosis for return to athletic activity. There is little documentation of the clinical and ultrasonographic features, clinical significance, and outcome for return to work following IPL injury in horses. The aim of this retrospective descriptive study was to describe the clinical and ultrasonographic features of IPL desmopathy, its association with other injuries of the stifle, and outcome for return to work following injury. Forty-two stifles with an ultrasound diagnosis of IPL desmopathy over a 5-year time period were included. Data regarding signalment, clinical presentation, diagnostic imaging findings, treatment, and outcome are described. Intermediate patellar ligament desmopathy occurred most commonly in the midbody (35/42; 83%) of the ligament and lesions were predominantly hypoechoic discrete tears (31/42; 74%) that were obliquely oriented in a craniolateral to caudomedial direction (28/42; 67%). Rarely (1/42; 2%) was IPL desmopathy the only ultrasonographic abnormality detected. Of 13 horses that underwent recheck ultrasound examination, the majority (11/42; 85%) either did not improve or worsened ultrasonographically. Despite this, of 25 horses with long-term follow-up, 23 (92%) returned to work, 16 at the same level or higher. A variety of treatments were utilized. The clinical significance of IPL desmopathy is difficult to determine because it is usually found in conjunction with other stifle abnormalities. Although IPL desmopathy rarely shows ultrasonographic improvement over time, prognosis can be good for return to work.

High field magnetic resonance imaging is comparable with gross anatomy for description of the normal appearance of soft tissues in the equine stifle.

High field magnetic resonance imaging (MRI) is increasingly used for horses with suspected stifle disease, however there is limited available information on normal imaging anatomy and potential incidental findings. The aim of this prospective, anatomic study was to develop an optimized high field MRI protocol for evaluation of the equine stifle and provide detailed descriptions of the normal MRI appearance of the stifle soft tissues, using ultrasound and gross pathological examination as comparison tests. Nine cadaver limbs were acquired from clinically normal horses. Stifles were evaluated ultrasonographically and then by an extensive 1.5 T MRI protocol. Subsequently, all stifles were evaluated for gross pathologic change. Findings were compared between gross evaluation and MRI imaging and described. No soft tissue structure abnormalities were identified on any evaluation. Specific descriptive findings of the meniscotibial, meniscofemoral, collateral, patellar and cruciate ligaments, and the menisci were reported. The high field MRI protocol described in this study provided high spatial and contrast resolution of the soft tissue structures, and this in turn allowed visualization of detailed structural characteristics, such as striations and variations in signal intensity. Findings supported the use of high field MRI as a modality for the evaluation of the soft tissues of the equine stifle. As clinical availability of this modality increases in the future, authors anticipate that new stifle diseases will be detected that have not previously been identified with other imaging modalities.

Pain: Its Diagnosis and Management in the Rehabilitation of Horses.

This article provides a brief overview of pain physiology and its relevance to equine patients. Objective and subjective techniques for assessing pain in the horse are described in depth. Pharmacologic and interventional pain modulation treatments are discussed with a focus on the rehabilitating horse.