REGIONAL OSTEOPOROSIS FOLLOWING TIBIAL SHAFT FRACTURES: ASSESSMENT OF BONE MINERAL DENSITY [BMD] SIXTEEN YEARS POST TRAUMA.

Abstract

The study was designed to determine the incidence and to quantify the risk factors of permanently decreased bone mineral density (BMD) of the Lumbar spine and Femoral neck following tibial shaft fractures.

42 consecutive adults treated for isolated tibial shaft fractures at our institution between January 1984 and June 1985 formed the subjects of this study. Mechanism and type of injury, method of treatment, length of immobilisation and weight bearing status and healing time were determined from the patient records. A questionnaire including history of smoking, alcohol consumption, medications, other fractures, medical conditions like thyroid/parathyroid disorders, convulsions, and renal disorders was administered. Bone mineral density of lumbar 1–4 vertebrae and both hips was assessed using DEXA scanning. T and Z scores were generated. Statistical analysis was performed using the Chi square test to test the significance of association of osteopenia/osteoporosis (Z score < -1) with a previous tibial shaft fracture and calculating the odds ratio (OR) and 95% confidence interval (CI) to quantify the suspected risk factors.

The incidence of significant loss of BMD of the ipsilateral femur and/or lumbar spine was found to be 33%. A statistically significant association (p< 0.001) between a history of tibial shaft fracture and permanent loss of BMD was noted. The following risk factors were found to be statistically significant; Smoking (OR 22, 95% CI=4–> 40, p< 0.001), Alcohol more than 20 units/week (OR 11, 95% CI 2.2–54,p< 0.005), Open fracture (OR 17, 95% CI=2.9–> 40, p< 0.001), Non-weight bearing more than 12 weeks (OR 15, 95% CI 2.9–> 40, p< 0.005), and delayed union defined as healing time more than 6 months (OR 15, 95% CI 1.54–> 40, p < 0.05).

Permanent regional osteopaenia/osteoporosis occurs in a significant proportion of tibial shaft fracture patients. Modern fracture management should include identifying ‘at risk’ patients and appropriate management to prevent fragility fractures.