The objective of this study was to determine if damage to the articular cartilage alone or articular cartilage plus subchondral bone of the distal medial femoral condyle of young, exercised horses resulted in the formation of subchondral cystic lesions. Twelve Quarter Horses (age 1-2 years), free of clinical and radiographic signs of osteochondrosis and lameness were used. In 6 horses (Group 1), a 15 times 1 mm linear full thickness defect in the articular cartilage was made arthroscopically on the weightbearing surface of the distal aspect of the medial femoral condyle. In the other 6 horses (Group 2), a 15 times 3 mm full thickness elliptical cartilage defect was made, followed by burring a 5 mm diameter, 4 mm deep hole into the subchondral bone. Three weeks after surgery, all horses were hand walked and trotted for 2 weeks and then exercised for 6 min daily, 5 days a week for the next 14 weeks on a treadmill. They were then turned onto a small paddock for 6 weeks (6 months total). The development of subchondral cystic lesions was determined using radiography. Bone activity in the femoral condyle was monitored with nuclear scintigraphy. All horses that developed subchondral cystic lesions radiographically were subjected to euthanasia for gross and histological examination of the lesions. No subchondral cystic lesions and no clinical abnormalities were detected in the horses in Group 1. Subchondral cystic lesions developed radiographically in 5 of 6 horses in (Group 2). Scintigraphic findings of horses with subchondral cystic lesions were inconsistent. Histological examination of lesions revealed variable quantities of fibrous connective tissue, fibrocartilage and bone, with evidence of bone remodelling adjacent to the subchondral cystic lesion. The results suggest that damage to articular cartilage plus subchondral bone, but not articular cartilage alone, of the distal medial femoral condyle may lead to the development of subchondral cystic lesions. These findings indicate that all subchondral cystic lesions in horses may not be osteochondrosis-type lesions and that trauma to weightbearing articular surfaces of young horses may be a predisposing factor.

The purpose of this retrospective analysis was to evaluate the use of nuclear scintigraphy in determining the rate of secondary sites of osseous malignancy at initial presentation in dogs with osteosarcoma. Radiographs of suspicious secondary lesions were reviewed and placed into four separate categories: benign lesions; no lesion seen on radiographs; subtle radiographic changes suggestive of, but not conclusive for, metastasis; and metastatic lesions highly suspected on radiographs. Three hundred and ninety-nine dogs were evaluated by technetium nuclear scanning for suspected osteosarcoma. Three hundred and twenty-six of 399 dogs (82%) had only one apparent site on the nuclear scan, whereas 72 dogs (18%) had more than one suspicious site on the nuclear scans. Highly suspected secondary metastatic lesions were detected by nuclear scans in 7.8% of cases. Although interpretation of nuclear scans is subjective, this study showed a 7.8% chance of detecting unsuspected osseous metastasis with nuclear scans in canine osteosarcoma patients on initial presentation.

Results suggest that in horses, the static magnetic field associated with application of commercially available magnetic wraps for 48 hours does not increase blood flow to the portion of the metacarpus underneath the wrap.

Although radiography is a more accurate method of measurement of the extent of distal radius osteosarcoma, because nuclear scintigraphy overestimates tumor length to a greater degree, scintigraphy may provide a larger margin of safety for determining the site of proximal osteotomy during a limb-salvage procedure. However, caution should be taken when utilizing scintigraphy, because this method may overestimate length of radius involved to such an extent as to cause the surgeon to believe that a patient is not a suitable limb-salvage candidate.

We have reported tablet-induced focal esophagitis and esophageal stricture formation in cats. The proposed mechanism is thought to be abnormal esophageal tablet retention resulting in focal esophagitis with subsequent stricture formation. The objective of this study was to evaluate the passage of tablets and capsules when given alone (dry swallow) and when followed by a water bolus (wet swallow) to determine if this could, in part, explain the esophageal stricture formation we have observed in cats. Fluoroscopy was used to evaluate tablet or capsule passage after administration. The percentage of dry tablet swallows that successfully passed into the stomach was 0.0% at 30 and 60 seconds, 6.7% at 90 seconds, 13.3% at 120 seconds, 26.7% at 180 and 240 seconds, and 36.7% at 300 seconds. Wet tablet swallows successfully passed 90.0% of the time at 30 seconds, 93.3% of the time at 60 seconds, and 100.0% of the time thereafter. The percentage of dry capsule swallows that successfully passed was 16.7% at each time interval. Wet capsule swallows successfully passed 96.7% of the time at 30 seconds and 100% of the time thereafter. For each time interval, wet swallows achieved significantly greater percentage passage into the stomach when compared to dry swallows (P Ͻ .05). This study shows that tablets or capsules given by dry swallow have prolonged retention in the esophagus compared to those given by wet swallow. On the basis of this study, we recommend the routine administration of a water bolus to cats receiving tablets or capsules PO to facilitate esophageal clearance. This practice may help prevent medication-associated esophagitis or stricture formation.