Hk. Uhthoff et al., CORTICAL POROSIS UNDER PLATES - REACTION TO UNLOADING OR TO NECROSIS, Journal of bone and joint surgery. American volume, 76A(10), 1994, pp. 1507-1512
Cortical porosis under plates used for the fixation of fractures is of
ten attributed to the interference of the plates with cortical perfusi
on, resulting in necrosis, which in turn induces remodeling. To our kn
owledge, no histomorphometric studies have been published that demonst
rate the correlation between cortical necrosis and porosis. The object
ive of this study was to test the hypothesis that cortical necrosis is
related to changes associated with porosis. Standard and railed plate
s mere applied to intact femora in ten dogs. Histomorphometric studies
done at eight and twenty-four weeks after insertion of the plate fail
ed to show a significant positive correlation between necrosis and por
osis irrespective of the type of plate used. Porosis was always greate
r in the inner cortical sector, where no increased necrosis was noted,
than in the outer cortical sector, where necrosis was present. CLINIC
AL RELEVANCE: Osteopenia under plates is a well accepted occurrence th
at causes weakening of bone. Reduction in the plate-bone contact area
has been recommended to reduce necrosis-induced porosis. Two important
findings contradict this recommendation: the absence of a positive co
rrelation between necrosis and porosis and the absence of a difference
in necrosis and porosis when plates with different bone-contact areas
, were used. Railed plates did not reduce the occurrence of necrosis o
r porosis.