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Summary Evaluation of the caudal distal antebrachium using ultrasound is a very useful diagnostic procedure for identification of soft tissue abnormalities in flexor structures of the equine limb. In this article we describe how ultrasonographic imaging may be used to complement radiography of the carpus in evaluating horses that present with peri-carpal swelling and/or lameness localised to the carpal region. Ultrasonographic examination assists with the identification or exclusion of significant injuries to muscular, tendonous and ligamentous structures within the distal antebrachium and enables practitioners to proceed with appropriate therapeutic and rehabilitation plans for the immediate benefit for their patients while also recognising pathology that could progress to cause long-term, chronic lameness issues without aggressive and effective intervention.

Equine carpal sheath effusion has multiple etiologies. The purpose of this retrospective study was to describe the prevalence of distinct musculoskeletal lesions lameness in a sample of horses with a clinical diagnosis of carpal sheath effusion. A total of 121 horses met inclusion criteria. Seventy-four percent (89/121) of horses were lame at presentation; middle-aged (9-18 years, 80%) and older (18 years, 85%) horses were lame more frequently than young horses (9 years, 44%). Ninety-three percent (113/121) were diagnosed with osseous and/or soft tissue abnormalities. Of these 113 horses, 10 exhibited osseous abnormalities, whereas 111 were diagnosed with soft tissue lesions. Eighty-four percent (93/111) of the soft tissue injuries extended from the caudodistal antebrachium to the palmar metacarpus. The superficial digital flexor tendon (98/111; 88%) and accessory ligament of the superficial digital flexor tendon (64/111; 58%) were the most commonly injured structures, with both structures affected in 41 (41/111; 37%) horses. Injuries within the caudodistal antebrachium included the superficial digital flexor musculotendinous junction (66), the accessory ligament of the superficial digital flexor tendon (64), and deep digital flexor muscle (21), in isolation or in combination with other structures. Increased echogenicity in the medial superficial digital flexor musculotendinous junction was detected in 40 horses and was significantly associated with increasing age (middle-aged, 19/40; old, 18/40). Findings from this study indicated that age should be taken into consideration for horses presented with carpal sheath effusion and that adjacent structures within the caudodistal antebrachium should be included in evaluations.

Ultrasonography and MRI have become valuable tools for imaging of tendon injuries. The current study examines the histopathologic basis for the imaging abnormalities. Five injured equine forelimbs and two normal contralateral limbs were studied with high resolution real time ultrasound and MRI. Histologic sections were made and correlated with the diagnostic images. All lesions were readily seen by both modalities. Lesions characterized by hemorrhage, edma, and cellular infiltration were sonolucent on ultrasound and bright on MRI images. MRI returned to normal as fibrogenesis ensued. Ultrasound images remained abnormal until fibrillar reallgnment occured with completion of the healing process. High resolution real time ultrasound and MRI both accurately reflect the tissue abnormalities in acute tendon injuries. The injured horse does appear to be an effective model for correlative imaging studies of tendon injuries.

Objective—To determine outcome of Standardbred racehorses with moderate to severe midbody suspensory ligament desmitis (MSD) treated by means of ultrasound-guided intralesional injection of a single dose of platelet-rich plasma (PRP) followed by a program of gradually increased exercise. Design—Nonrandomized clinical trial. Animals—9 Standardbred racehorses. Procedures—Following injection of PRP, horses were allowed a controlled, gradual return to exercise. Race records for the year prior to injury and for 3 consecutive years after horses returned to racing were reviewed. For comparison purposes, race records of 9 Standardbred racehorses with no history of MSD racing at the same time were also reviewed. Results—All 9 horses with MSD returned to racing after treatment; median time to return to racing was 32 weeks. All 9 horses raced at least once during the first and second years after returning to racing, but only 5 raced during the third year. When number of starts, total earnings, and earnings per start were compared between case and comparison horses, the only significant differences were number of starts during the third year after case horses returned to racing and earnings per start during the first year after case horses returned to racing, with values being significantly lower for case horses than for comparison horses. Conclusions and Clinical Relevance—Results suggested that horses with moderate to severe MSD treated by means of intralesional injection of a single dose of PRP followed by a program of gradually increased exercise had an excellent prognosis for returning to racing.

A method to quantitate as well as to document SDFT pathology has been described. This report indicates that computer-assisted evaluation of SDFT damage can improve the accuracy of prognosis in clinical practice. It would appear that a 3.8 severity rating is a limit past which prognosis for successful racing starts to worsen rapidly.

The authors of this section represent a broad range of practice experience with horses that perform in rigorous and varied sport competitions. Each breed and performance application represent unique challenges of diagnosis and uncompromising demands on rehabilitated tendon injuries. This article will serve to guide, stimulate, and encourage veterinarians to apply scientific criteria to the evaluation of tendinitis therapy in the years to come so that we can arrive at a more valid consensus as to the “best” means of tendon and ligament injury management.

Summary The textural and dimensional characteristics of the appearance of the normal suspensory ligament lends itself well to diagnosis of clinical disease of this structure. Following injury to the suspensory ligament there are changes that involve inflammation, and structural compromise. These changes may be manifest in a spectrum of severity, and documentation may be provided using real- time ultrasound imaging. Ultrasound imaging of the soft tissues in the equine extremity is an important aid; in diagnosis of lameness, prognosis, monitoring of healing, and retrospectively, in determining the more efficacious therapeutic regimens. To illustrate pathologic change of the suspensory ligament, selected cases of suspensory desmitis with varying degrees of severity are discussed.

In our 3 years of clinical experience, we have found that diagnostic ultrasound provides the veterinarian with a valuable diagnostic tool. It allows the clinician to quantify morphologic change that has occurred as a result of soft-tissue injuries, even when the clinical findings are ambiguous or insufficient. In cases in which aggressive postinjury therapy has been instituted prior to presentation, diagnostic ultrasound is often the only noninvasive method that can ascertain the extent of the horse's injury. Diagnostic ultrasound provides the technology to detect injuries before they become permanently debilitating, because lesions as small as 1 mm in diameter can be detected. Prior to diagnostic ultrasound, the severity of many injuries was underestimated. In such cases, if the horse responded favorably to symptomatic therapy, the client would resume training. The result was often debilitation. Diagnostic ultrasound also enables the clinician to demonstrate visually to the client the location, size, and extent of lesions in the limb. One of the more gratifying effects of a sonographic study is the client's acceptance of the presence and extent of the injury after visualizing it. We have found that the old adage "a picture is worth a thousand words" is generally the rule in obtaining the proper course of therapy for the horse. The ability to make hard copies of sonograms enables the clinician to morphologically evaluate the rate of healing. He can accurately determine the effectiveness of a therapeutic regimen and ascertain when optimal healing has occurred. Diagnostic ultrasound can provide the researcher with an invaluable tool to document and quantify soft-tissue disease. We anticipate that, in the future, the sonographic appearance of recovered tissues will be correlated with new data on the healing process and the effectiveness of various therapies. The material presented above has covered the value of diagnostic ultrasound in major clinical situations related to equine lameness. Other applications, the discussion of which is beyond the scope of this article, include evaluation of the pastern for injuries to the SDF, DDF, and oblique sesamoidean ligament, and evaluation of the navicular bursae. Examination of muscles for hematomas, abscessations, and tears has also been accomplished ultrasonographically. Diagnostic ultrasound has facilitated study of the trochanteric and bicipital bursae, blood flow through arteries, and structures above the carpus and hock. Obviously, the clinical potential of diagnostic ultrasound is limitless.(ABSTRACT TRUNCATED AT 400 WORDS)