The effectiveness of regenerating versus mature marrow in physiologic autogenous transplants

Differences in rates of bone healing in animals and in human extraction wounds suggest that marrow tissue is more likely to form bone when transplanted at the onset of its most active regenerative period rather than at its maturity. To test this hypothesis, small segments of polyvinyl sponge were implanted into experimentally produced femur cavities in Sprague-Dawley rats, to provide matrices for regenerating cellular structure in the grafting procedures. Bone resulted in 16 of 22 cases (72.7%) in which regenerating marrow was transferred to the anterior eye chamber, compared with 4 of 23 cases (17.4%) in which mature marrow was used (P = 0.0002). No bone resulted when washed, polyvinyl sponge samples were implanted as controls in 6 cases. These findings indicate that with existing techniques it is probably more effective to transplant regenerating marrow than mature marrow.