CALCIUM BUFFERING IS REQUIRED TO MAINTAIN BONE STIFFNESS IN SALINE SOLUTION

This work determined whether mineral dissolution due to prolonged test ing or storage of bone specimens in normal saline would alter their el astic modulus. In one experiment, small pieces of equine third metacar pal bone were soaked in normal saline supplemented with varying amount s of CaCl2. Changing Ca ion concentrations in the bath were monitored and the equilibrium concentration was determined. In a second experime nt, the elastic moduli of twenty 4 x 10 x 100 mm equine third metacarp al beams were determined non-destructively in four-point bending. Half the beams were then soaked for 10 days in normal saline, and the othe r half in saline buffered to the bone mineral equilibrium point with C a ions. Modulus measurements were repeated at 6 and 10 days. The equil ibrium Ca ion concentration for bone specimens was found to be 57.5 mg l(-1). The modulus of bone specimens soaked in normal saline significa ntly diminished 2.4%, whereas the modulus of those soaked in calcium-b uffered saline did not change significantly. Copyright (C) 1996 Elsevi er Science Ltd.