A pump to deliver bone-growth factors to a carrier matrix within a patient. Pump can be internal or external. With external pumps, additional amounts of the same growth factor may be added, or the bioactive agent may be changed during the course of treatment. An external pump permits the use of cells to promote bone growth. The pump can have several reservoirs and the pump can itself be received in the carrier matrix with an outlet tube or other structure to defuse the growth factors into the carrier matrix. The pump protocol can be used for slow-to-heal fractures, such as closed fractures, and can be used for slow-to-heal patients.