Does the crack silently break the back? Long-term follow-up and assessment of risk factors for regional osteoporosis following tibial shaft fractures

The aim of this study is to determine the incidence and to quantify the risk factors for developing long-term regional osteopenia/osteoporosis (RO) following tibial fractures.We studied 42 adult subjects (8 females and 34 males) who had sustained a tibial fracture 16 yr prior to the study. Mechanism and type of injury, method of treatment, length of immobilization, weight-bearing status, and healing time were determined from the patient records. A questionnaire covering known causes of generalized osteoporosis (GO), including history of smoking, alcohol consumption, medications, other fractures, thyroid/parathyroid disorders, epilepsy, and renal disorders, was answered by all the subjects. Bone mineral density (BMD) of lumbar vertebrae 1-4 and both proximal femurs was assessed using dual-energy X-ray absorptiometry (DXA) scanning. T- and Z-scores were generated. Assessment of risk factors was done by calculating the odds ratio (OR) and 95% confidence interval (CI). The incidence of significant loss of BMD as defined by the World Health Organization (T-score <-1) of the ipsilateral neck of femur and/or lumbar spine was found to be 40%. None of our subjects had any known cause for GO. The following risk factors were found to be statistically significant in unadjusted models: smoking (OR 22, 95% CI = 4 - >40), alcohol >20 units/wk (OR 11, 95% CI 2 = 2-54), open fracture (OR 17, 95% CI = 2.9 - >40), nonweight bearing >4 wk (OR 15, 95% CI 2.9- >40), and delayed union defined as healing time more than 6 mo (OR 15, 95% CI 1.54 - >40). Permanent regional loss of BMD occurs in a significant proportion of tibial shaft fracture patients. Modern fracture management should include identifying "at-risk" patients and appropriate preventive measures to prevent fragility fractures.