Provided is an implantable composite which includes a plurality of resorbable ceramic particles with or without a biodegradable polymer. The resorbable ceramic particles can be granules including carbonated hydroxyapatite and tricalcium phosphate in a ratio of 5:95 to 70:30. Some resorbable ceramic particles are granules, which include carbonated hydroxyapatite and β tricalcium phosphate in a ratio of 5:95 to 70:30. The resorbable ceramic particles have a particle size from about 0.4 to about 3.5 mm. The implantable composite is configured to fit at or near a bone defect as an autograft extender to promote bone growth. Methods of using the implantable composite are also provided.