gms | German Medical Science

Objectives/Interrogation: The purpose of this study was to evaluate the osseous healing of a critical-sized tibia shaft defect in rat model with the use of three platelet concentrates: PRP, defrosted PRP and PRF. The shaft of rat tibia as a model was used because of its subcutaneous position similar to hand phalanges and metacarpals.

Methods: Intramuscular anesthesia was used. Critical-sized 5-6 mm-long midshaft defect of the right tibia of 73 male cross-breed rats (weight 420-500 g, age 5-6 months) was created and secured with a pre-bend gauge plate and screws, and a fragment of 22G needle placed intramedullary. In group 1 (24 animals) the bone defect was filled with hydroxyapatite-collagen biomaterial and orthotopic bone chips 1:1 mix, infused with 0,2 ml fresh allogeneic PRP. In group 2 (23 animals) the defect was filled with the same biomaterial - bone chips mix, infused with 0,2 ml cold-stored and defrosted allogeneic PRP. In group 3 (12 animals) allogeneic Choukroun's PRF was added to the biomaterial - bone chips mix. In group 4 (14 animals) the defect received biomaterial - bone chips mix alone and no platelet concentrate was added.

Animals were sacrificed at 6 and 12 weeks, at 4,5; 6; 7,5; 9 and 12 months and 2 rats from group 4 - at 24 months. Both tibia and fibular bones were dissected and the presence of new bone formation in the tibia defect was examined. Bones were fixed in formalin and embedded in paraffin after decalcifying and hardware removal. Longitudinal histological sections were stained with hematoxylin and eosin.

Results and Conclusions: According to the data from dissection, in PRP group 19 animals of 24, in defrosted PRP group 15 animals of 23 and in PRF group 8 animals of 12 demonstrated new bone formation in the defect. There was no detectable bone formation over the 24 months period in no platelets concentrate group 4. On histologic analysis at 6 weeks to 12 months after surgery 42 of 59 rats (71,2%) from groups 1, 2 and 3 demonstrated more or less mature bone formation in the defect and an increase in calcified bone formation over time. Group 4 showed no histologic evidence of bone formation.

Results demonstrate that either of the three platelets concentrates added to hydroxyapatite-collagen biomaterial promotes bone formation and healing of critical-sized segmental bone defect in rat model. Thus PRP, defrosted PRP and PRF autologous techniques may provide other options for reconstruction of hand bones segmental defects in cases where biomaterial alone is not sufficient to heal the defect.