an improved bone cement is comprised of a particulate biocompatible calcium phosphate ceramic and particulate resorbable calcium salt dispersed in a cross - linked biodegradable polyester matrix . the polymer / salt - particle composite exhibits good biomechanical strength / modulus characteristics with surgically acceptable cure times . when used for sustained release of biologically active agents in a physiological environment , controlled release of biological agents that are mixed into the composite can be achieved as the cement biodegrades . when used for bone / implant fixation , or as a filler or cement for bone repair , gradual biodegradation of the cement composite permits , under suitable circumstances , evantual replacement of the cement with developing bone tissue .