SCINTIGRAPHIC EVALUATION OF FRACTURES OF THE DISTAL PHALANX IN HORSES- 27 CASES (1979-1988)

Retrospective radiographic and scintigraphic analyses were performed o n 27 fractures of the distal phalanx in 25 horses. Location of technet ium methylene diphosphonate (Tc-99m-MDP) uptake was compared with frac ture line location as seen on radiography. Intensity (intense, moderat e, mild) and pattern (focal, diffuse) of Tc-99m-MDP uptake was recorde d and compared with duration of fracture. Nine horses were monitored d uring convalescence by obtaining additional scintigraphic views 3 to 6 8 months after injury. Palmar scintigraphic views had evidence of foca l areas of increased Tc-99m-MDP uptake that corresponded to fracture l ine location as seen on radiography. Lateral scintigraphic views had e vidence of diffuse increased uptake. There was a significant (P < 0.01 ) association between duration of fracture and intensity of uptake, wi th fractures < 3 months in duration more likely to have intense focal uptake. All fractures < 10 days in duration had intense focal uptake. As fracture age increased, Tc-99m-MDP uptake became less intense and m ore diffuse. Three fractures not evident on radiography had evidence o f Tc-99m-MDP uptake on scintigraphy. Stall rest resulted in decreased Tc-99m-MDP uptake in 6 of 9 horses, but increased uptake was still vis ible in all horses between 4 and 25 months after injury. The only scin tigraphic view without evidence of increased uptake was that obtained from a horse reexamined 68 months after injury.