CLINICAL RELEVANCE OF ABNORMAL SCINTIGRAPHIC FINDINGS OF ADULT EQUINE RIBS

Horses with cranial rib abnormalities may exhibit severe acute lameness and may have unusual gait deficits characterized by forelimb abduction during protraction at the walk. Horses with caudal rib abnormalities may resent being saddled and ridden. In a retrospective evaluation of 20 horses with a documented rib lesion, 25 sites of increased radiopharmaceutical uptake were found in one or more ribs. Thirteen (52%) scintigraphic lesions involved the first rib; four were located immediately dorsal to the sternal articulation, eight were near the costochondral junction and one was at the costovertebral junction. Six (24%) scintigraphic rib lesions involved ribs 2–8; one was located immediately dorsal to the sternal articulation, three were at the costovertebral junction and two were near the costochondral junction. Six (24%) scintigraphic rib lesions involved the mid‐portion (five) or costovertebral junction (one) of ribs 9–18. The 20 horses were divided into three groups based on the clinical relevance of the scintigraphic findings. Group 1 (n=3) horses had clinical signs attributed to a rib abnormality; Group 2 (n=6) horses had a rib abnormality that was a plausible explanation for clinical signs; Group 3 (n=11) horses had clinical signs that could not be attributed to a rib abnormality. For horses with cranial rib abnormalities, a modified lateral scintigraphic image with the ipsilateral limb pulled caudally and a left (right) 45° caudal–right (left) radiograph facilitated the diagnosis.     

Surgical Repair of Mid‐body Proximal Sesamoid Bone Fractures in 25 Horses

Objective— To describe the characteristics of unilateral mid‐body proximal sesamoid bone (PSB) fractures, to determine factors associated with the outcome of horses after surgical repair, and to describe a technique for arthroscopically assisted screw fixation in lag fashion. Study Design— Retrospective case series. Animals— Horses (n=25) with unilateral mid‐body PSB fracture. Methods— Medical records (1996–2006), radiographs, and arthroscopic videos of horses with surgically repaired unilateral mid‐body PSB fractures were reviewed. Retrieved data included signalment, affected limb and PSB, fracture characteristics, and surgical technique. Outcome was established by radiographic assessment of healing and race records; categorical data were analyzed using Fisher's Exact test. Results— Medial forelimb PSBs were most commonly affected (80%). Surgical technique and degree of reduction were significantly associated with outcome; 44% of horses with screw repair and none of the horses with wire fixation raced (P=.047). Factors that may have influenced this outcome were differences in fracture reduction (improved reduction in 22% wire repairs and 88% screw repairs, P=.002) and use of external coaptation (22% wire repair and 88% lag screw repair, P=.002). None of the horses with unimproved reduction raced after surgery. Conclusions— Only 28% of horses with mid‐body PSB fractures raced after surgery. Compared with wire fixation, screw fixation in lag fashion resulted in good reduction and is seemingly a superior repair technique. Clinical Relevance— For mid‐body PSB fractures, arthroscopically assisted screw fixation in lag fashion and external coaptation for anesthesia recovery and initial support provides the best likelihood of return to athletic use.     

Surgical Repair of Congenital Lateral Luxation of the Patella in the Foal and Calf

Repair of lateral luxation of the patella in horses and cows has consistently produced poor results; reluxation, muscle atrophy, septic arthritis, and degenerative joint disease are frequent postoperative complications of the techniques previously described. A new technique for repair of congenital lateral luxation of the patella in foals and calves is described; it includes lateral release of the patella followed by imbrication of the medial aspect of the joint capsule. Postoperative evaluation, up to 1½ years, confirmed the efficacy of the technique with retention of normal patellar position and range of motion. Muscle atrophy and lameness disappeared completely in 2 animals, which showed no radiographic evidence of degenerative joint disease at the time of surgical repair. Since the preparation of this article, 3 more calves have been successfully repaired with excellent clinical results up to 12 weeks postoperatively.     

Orbital Surgery in Two Horses

The case histories of 2 horses that required surgery within the orbit are described. In 1 horse, severely comminuted fractures of the left facial area and orbit were repaired in 2 stages, the first consisting of elevation and wiring of the depressed fractures. In the second stage, an autogenous tendon graft from the lateral digital extensor tendon of the left front leg was used to reconstruct the orbital floor and elevate the globe in the orbit. In the second horse, a retrobulbar tumor causing exophthalmos and prolapse of the nictitans was removed by creating a bone flap of the zygomatic process of the frontal bone for exposure.