Estimation of the rate of osteogenesis by tetracycline double labeling in intertrochanteric fractures of the femur in different age groups and its correlation with radiological grading of osteoporosis.

Our aim was to estimate the rate of osteogenesis by using tetracycline double labeling and to correlate it with the radiological grading of osteoporosis in patients of intertrochanteric fracture of the femur in different age groups. Thirty-two cases of intertrochanteric fracture of the femur of either sex, without any associated osteopenic conditions, who were admitted for surgery constituted the clinical material. The cases were divided into three age groups: group I, <45 years; group II, 45-60 years; and group III, >60 years. Osteoporosis was graded in all groups on plain X-rays by Singh's index (SI) and metacarpal index (MI). The patients were labeled with a single large dose (1.5 g) of tetracycline orally on day 1 and day 8. An iliac crest bone biopsy specimen was obtained from each of the patients during surgical intervention. Thin undecalcified sections were made by the hand grinding technique. The sections were studied under UV light for presence of fluorescence, and rate of osteogenesis (mineral appositional rate, MAR) was calculated for each of the groups. Only 7 patients were found to have radiological osteoporosis (by Singh's index). The average MI and MAR were found to be 46.5% and 1.48 microm/day, respectively. The single-dose labeling schedule has shown good fluorescent bands, comparable to the conventional dose schedule. No correlation was found between Singh's index and metacarpal index in group I and III, whereas in group II it was significant. There is no significant correlation between the rate of new bone formation and the radiological grading of osteoporosis.