Osteoporosis is not a risk factor for the development of nonunion: A cohort nested case-control study

INTRODUCTION: Osteoporosis (OP) is one of the most prevalent metabolic bone disorders worldwide and it is associated with a higher incidence of fractures. The aim of this study was to identify OP as a risk factor for the development of nonunion. METHODS: In a prospective database all patients aged >50 years with an acute fracture were screened for osteoporosis from September 13, 2004 till February 9, 2009. Bone mineral density measurements (T-scores, Z-scores and absolute values in g/cm(2)) were performed. The selected patients were matched (1:2 ratio) to control patients based on gender, age (+/-5 years) and type of fracture according to the AO-criteria. Other parameters including diabetes mellitus, corticosteroid use, rheumatoid arthritis, smoking, alcohol use, and body mass index were recorded. Follow-up for the patients in the matched group was at least one year. RESULTS: This study included a total of 1498 patients who were screened for the presence of osteoporosis. In total 40 patients were treated for nonunion. After 1:2 matching this resulted in a total number of 120 patients for analysis. Logistic regression analysis including all covariates in the model demonstrated no correlation between the standardised regression coefficients and the development of nonunion (r(2)=0.10, p=0.6). The patients that developed an atrophic nonunion, according to radiographic results, were analysed separately and compared to matched patients. The presence of osteoporosis, osteopenia and normal bone density and the related independent BMD measurements did not differ significantly between the atrophic nonunion group and the matched controls. CONCLUSION: We conclude that although bone quality may be diminished in the elderly this does not influence the occurrence of nonunion. These results indicate that the use of BMD measurements preoperatively to identify osteoporosis as a possible risk factor of nonunion has no clinical value.