Recombinant growth hormone accelerates bone regenerate consolidation in distraction osteogenesis

The purpose of the present study was to prove whether homologous GH has a s timulating effect on bone healing. Therefore, left tibiae of 30 micropigs w ere osteomized and distracted over an external fixator at the rate of 2 mm/ day on each of 10 consecutive days. Animals were killed after a healing per iod of another 10 days. The treatment group received 100 mu g of recombinan t porcine growth hormone (rpGH) per kilogram of body weight per day. Serial torsional nondestructive biomechanical tests were performed in vivo using a newly developed measurement device. After killing, destructive torsional strength testing of the sites of distraction was performed. To determine th e endocrine response to the administration of rpGH, serum levels of insulin -like growth factor-I (IGF-I) were determined. Nondestructive in vivo testi ng showed that torsional stiffness of the regenerate was significantly high er in the treatment group than in the control group. Final regenerate torsi onal failure load was 131% higher and ultimate torsional stiffness was 231% higher in the treatment group than in the control group. The mean serum le vel of IGF-I increased to 440% of preoperative basal level in the treatment group and remained unchanged in the control group. Our data indicate that systemic administration of recombinant homologous growth hormone greatly ac celerates ossification of bone regenerate in distraction osteogenesis, (Bon e 24:81-88; 1999) (C) 1999 by Elsevier Science Inc. All rights reserved.