Epiphyseal Plate Shear Strength in Rats Treated with a Diphosphonate

Rats treated with a small dose (0.5 mg P/kg/day) of dichloromethylene diphosphonic acid (C1²MDP) exhibited a marked increase in the shear strength of the proximal tibial epiphyseal plate with no suppression of longitudinal growth. Our results suggest that mechanisms in addition to the absorption of diphosphonate onto hydroxyapatite crystals account for the increase in epiphyseal plate shear strength noted in our experiment. In this regard, this diphosphonate could be valuable in studies of the normal determinants of epiphyseal plate shear strength. In addition, since C1²MDP increased epiphyseal plate strength without suppressing longitudinal growth, the compound may eventually prove to be useful in the treatment of epiphyseal displacements in humans.