RADIOGRAPHIC DETECTION OF SINGLE-LEG FRACTURE IN BJORK-SHILEY CONVEXO-CONCAVE PROSTHETIC VALVES - A PHANTOM MODEL STUDY

Cineradiography can identify patients with single-leg fractured Bjork- Shiley Convexo-Concave valves, although little is known about the sens itivity and specificity of this technique. We evaluated three normal a nd six (0 mu m gap) single-leg fractured Bjork-Shiley valves that were placed in a working phantom model. Valves were randomly imaged a tota l of 33 times and duplicated into a 120-valve series with a 1:9 ratio of abnormal/normal valves. Six reviewers independently graded each val ve and demonstrated markedly different rates of identifying the fractu red valves. Average sensitivity at the grade that clinically results i n valve explanation was 47%. Among the normal valves, a correct identi fication was made 96% (range 91% to 99%) of the time. Present radiogra phic technology may have significant difficulty in identifying true si ngle-leg fracture in Bjork-Shiley valves with limb separations that ar e common among clinically explanted valves.