Radiographic anatomy of the soft tissue attachments of the equine stifle.

REASONS FOR PERFORMING STUDY: Radiography is a very important aspect of equine stifle imaging. The precise radiographic anatomy of the soft tissue structures of the equine stifle has not been described previously. OBJECTIVE: To describe the anatomical relationship between sites of attachment of soft tissue structures of the equine stifle and their locations on standard radiographic views. METHODS: The sites of bony attachments of the tendons, ligaments and fibrous portion of the joint capsules of equine stifles were determined by gross dissection. These sites of attachment were transposed onto one set of bones deprived of soft tissue and mapped using radiopaque markers. This specimen was then radiographed in the standard radiographic projections (lateromedial, caudocranial and caudal 60 degrees lateral-craniomedial oblique) to determine the position of the attachment sites on the radiographs. RESULTS: Two radiographic maps were drawn per radiographic projection, one for the attachment sites of the ligaments and tendons and one for the attachment sites of the joint capsules. CONCLUSIONS AND POTENTIAL RELEVANCE: The radiographic maps of the precise position of the soft tissue attachments of the tendons, ligaments and joint capsules of the equine stifle should assist interpretation of equine stifle radiographs.

Effect of age at presentation on outcome following arthroscopic debridement of subchondral cystic lesions of the medial femoral condyle: 85 horses (1993--2003).

REASONS FOR PERFORMING STUDY: Subchondral cystic lesions of the medial femoral condyle (SCMFC) are well documented in horses < or =3 years; arthroscopic debridement or enucleation of the cyst is currently the surgical treatment of choice. However, studies of occurence and outcome following surgery in older horses are lacking. OBJECTIVE: To identify factors important in outcome for horses with SCMFC treated by arthroscopic debridement. HYPOTHESIS: Age of horse at presentation has a significant influence on return to work following arthroscopic treatment for SCMFC. Clinical and diagnostic findings are also significant with respect to prognosis. METHODS: A retrospective review of medical records from 6 equine referral centres identified 85 horses that underwent arthroscopic debridement of SCMFC. Clinical examination, radiographic and arthroscopic findings were analysed together with follow-up data. Univariable analysis and multivariable logistic regression models were used to determine factors affecting return to soundness. Event-time analysis was performed to evaluate return to work. RESULTS: Older horses (>3 years) were less likely to return to soundness (P = 0.02) or to work (P = 0.04) than younger horses (< or = 3 years). Of 39 horses age 0-3 years, 25 (64%, 95% CI 49-79%) returned to soundness. Of 46 horses age >3 years, 16 (35%,95% CI 21-49%) returned to soundness. In addition, cartilage damage at sites other than the SCMFC negatively affected prognosis (P = 0.05). The hospital where treatment was performed had no influence on return to soundness. CONCLUSIONS: Older horses carry a worse prognosis for both return to soundness and return to work. POTENTIAL RELEVANCE: It is important for clients to be made aware of the difference in outcome between age groups.

Lameness associated with the bicipital bursa in an Arab stallion.

Severe, chronic lameness in the left forelimb of a five-year-old Arab stallion was localised to the bicipital bursa by local anaesthesia and gamma scintigraphy. Radiographic and ultrasonographic examinations of the proximal humeral tubercles and bicipital bursa revealed new bone production in the region of the intertubercular grooves and irregularities in the density of the soft tissues of the bicipital tendon and bursa. An endoscopic examination of the bicipital bursa with a standard arthroscope under general anaesthesia was a useful diagnostic procedure. The stallion was euthanased, and marked fibrocartilage fibrillation and formation of adhesions were found postmortem, confirming a diagnosis of chronic fibrinous bursitis.

Treatment of sepsis in the small tarsal joints of 11 horses with gentamicin-impregnated polymethylmethacrylate beads.

Gentamicin-impregnated polymethylmethacrylate beads were used to treat infective arthritis in the small tarsal joints of 11 severely lame horses. Under general anaesthesia, between five and 10 beads were placed into a 7 to 8 mm tract drilled across the affected joint and, in all except one horse, they were left in place for 14 days. Two of the horses were euthanased for reasons other than persistent tarsal joint sepsis, but the other nine survived and seven of them returned to their previous level of athletic performance.

Resection of the common digital extensor tendon in a gelding.

A four-year-old gelding was lame owing to a chronic septic common digital extensor tendon and sheath. The horse had been treated by open surgical lavage but the sepsis had recurred after three months. Physical, ultrasonographic, cytological and histological examinations confirmed chronic septic tenosynovitis and tendonitis. The entire intrathecal component of the common digital extensor tendon was resected under general anaesthesia and the synovial lining of the sheath was ablated. Postoperatively the horse regained good limb function and became sound.

Endoscopic electrosurgical excision of laryngeal granulation tissue in a standing pregnant mare.

An 11-year-old, eight-months pregnant mare suddenly developed severe respiratory distress. Endoscopic examination identified intralaryngeal granulation tissue obstructing the airway. In order to avoid general anaesthesia and the problems associated with a permanent tracheostomy, the mass was resected electrosurgically while the mare was standing. Patency was restored to the airway and the mare foaled without complication.

Diagnosis and treatment of retropharyngeal injuries in lambs associated with the administration of intraruminal boluses.

The administration of intraruminal identification boluses to a group of 76 lambs resulted in 24 (32 per cent) showing signs of pharyngeal damage. In 16 of them the bolus was found to be in the retropharyngeal region by means of a hand-held microchip scanner, radiography and endoscopy. Purulent tracts were identified in the dorsal pharynx. In 13 of the 16 lambs the surgical removal of the bolus under general anaesthesia was followed by a normal clinical recovery, although the lambs did not grow as well as similar unaffected animals; three of the 24 lambs died. The administration of a larger bolus to 10 yearling rams did not result in any clinical signs of pharyngeal damage. The most important factors influencing the occurrence of this type of injury among this group of lambs were the size and age of the lambs, the positioning of the lambs during bolus administration, the relative size of the dosing gun and bolus, and the large number of animals in the group.

Clinical findings associated with chronic ischial fracture in a gelding.

An 8-year-old show-jumper gelding was referred for examination as a result of a purchase dispute for reported back pain. Clinical examination identified back pain and atrophy of the left semimembranosus and semitendinosus muscles, but no lameness. Standing pelvic radiography demonstrated a chronic nonunion fracture of the left ischium, the clinical significance of which was uncertain. The apparent back pain was thought to be probably unrelated to the pelvic lesion. We conclude that chronic ischial fracture in the horse can lead to specific atrophy of the semimembranosus and semitendinosus muscles, which originate from this bone.

Entrapment of the small colon through a mesocolic rent in a mare.

A 6-year-old mare was presented for acute abdominal pain unresponsive to analgesics. Exploratory laparotomy revealed entrapment of the small colon through a 12 cm rent in the mesocolon. The incarcerated small colon was manually reduced and the rent in the mesocolon was sutured closed. The mare made excellent postoperative recovery and was discharged from the hospital 4 days later. The cause of the rent, which was chronic in appearance, is unknown.