Objective: To explore the difference of bone formation potential between hypertrophic nonunion tissue and atrophic nonunion tissue, which may be beneficial to nonunion therapy.
Methods: From October 2010 to March 2014, 40 nonunion tissue samples were collected in Department of Orthopedics, Second Xiangya Hospital. The samples were divided into a hypertrophic nonunion group (n=20) and an atrophic nonunion group (n=20) according to nonunion character; or a 20 to 35 years old group (n=18), a 36 to 50 years old group (n=18), a more than 50 years old group (n=4) according to different ages; or a 9-12 months group (n=21), 13-24 months group (n=14) and a more than 24 months group (n=5) according to different nonunion time. Semi-quantification was performed by SP immunohistochemical method and IPP6.0 was used to analyze the expression of bone morphogenetic protein-2 (BMP-2) through measuring the mean optical density.
Results: The mean optical density of BMP-2 was 0.1540±0.0408 in hypertrophic nonunion tissue, 0.1372±0.0372 in atrophic nonunion tissue, there was no significant difference between the 2 groups (P>0.05). The mean optical density of BMP-2 was 0.1477±0.0379 in the 20 to 35 years old group, 0.1419±0.0399 in the 35 to 50 years old group, 0.1456±0.0595 in the more than 50 years old group, there was no significant difference among the three groups (P>0.05). The mean optical density of BMP-2 was 0.1449±0.0366 in the 9-12 months group, 0.1472±0.0400 in the 13-24 months group, 0.1445±0.0541 in the more than 24 months group, there was no significant difference among the 3 groups (P>0.05).
Conclusion: The present results suggest that the hypertrophic nonunion tissue share similar osteogenic potential with the atrophic nonunion tissue.