Introduction and Objectives: Growth factors with osteoinductive capacity can be considered biomaterials with significant activity in repair and regeneration processes in live beings. We carried out a study of an isolated application of a component rich in platelets and growth factors, platelet rich plasma (PRP), in a bone defect,

Materials and Methods: We carried out an experimental controlled prospective bilaterally comparative study in 30 New Zealand rabbits, with 6 mm diameter defects in the proximal metaphysis of the tibia and diaphysis of the fibula. The animals were divided into 2 groups of 15 individuals that received platelet rich plasma (PRP) or plasma poor in platelets (ppp) in their right tibia and fibula. The left tibia and fibula were used as non-treated controls. X-rays, CT scans and histological studies were assessed at 8, 12 and 16 weeks.

Results: The CT scans, bone mineral density and histological studies showed improvement in the group treated with plasma poor in platelets (ppp) without any significant differences. Repair processes took place through membranous ossification. On statistical assessment, no significant statistical difference between variables was found.

Discussion and Conclusions: In our experimental study of bone defects in experimental animals we did not find that platelet rich plasma, substance or autologous compound, had any osteoinductive or osteopromoting capacity.

Aims: Several surgical methods to treat varus knee deformities in young patients are known. In the present study the surgical procedure and the medium and long term results of the treatment with opening wedge valgus high tibial osteotomy are analysed. Methods: 27 cases in 11 patients are analysed. Average age: 21 years. 5, ales and 4 females. 8.3 years of follow-up. Surgical procedure: ßuoroscopic control. References: femoral head, knee centre and ankle centre. Osteotomy: Opening wegde valgus high tibial osteotomy. Correction: alignement according tomechanical axis. Bone grafting: autogenous bone grafts and osteotoconduction material. Osteosynthesis with a plate. Knee dynamic orthoses until fusion is achieved. Results: No pre or post-operative complications. Consolidation before 2.5 months in all cases with early full weight-bearing. Results analysed according to the scoring scales: Excellent/Good: 24 cases, Fair: 3 cases, Poor: 0 cases. Conclusions: Opening wedge valgus high tibial osteotomy is an excellent method to correct varus knee deformities in young patients. It does not usually present complications and the correction achieved in the post- operative persists in time in all our cases.