were randomly divided in 4 groups: in 1st and 2nd grs. 10 animals received 3 intra-articular injections of PAP (on 5th,7th,14th day after knee trauma) as a control (gr.3 and 4) 10 rabbits received 3 intra-articular injections of 0,9% NaCl at the same days after trauma; histopathology was performed at 45th (1st and 3rd gr.) & at 90th day (2nd and 4th gr.) after trauma. 146 patients-58 men (39.7%) & 88 women (60.3%), were divided into 2 grs. Gr.1 included 68 patients who consented to receive standard OA treatment and 3 weekly intra-articular injections of PAP (total 2 courses in 12 months) (plasma volume 12-15ml/course, total platelets number per injection 1260,24±22,1x10 9); Gr.2 consisted of 78 patients with the same diagnosis who received only standard OA treatment (non-steroidal anti-inflammatory drugs, physiotherapy, exercises). Both groups were of comparable age, gender and initial WOMAC data (Gr.1 40,9±0,7 Gr.2 39,7±0,9, p>0,05). WOMAC scale parameters were analyzed before treatment and after 3 weeks; 6 & 12 months after course of treatment in both groups. Results: In animals histopathology has found better repair, ↓ inflammation, better structure of the knee cartilage after PAP injections comparing with the control groups animals; in addition in 3rd group of rabbits ↓ signs of early posttraumatic osteoarthritis were found (comparing to 4th gr.). Clinical study demonstrated better changes in pain, stiffness and function in 3 weeks after treatment in patients of Gr.1 comparing to Gr.2 (WOMAC had decreased by 35.8% in Gr.2 and by 74.1% in Gr.1), p<0,05. After 6 months of follow-up (before 2 course of PAP treatment), the mean number of OA exacerbations was (0,7±0,02) in Gr.1 & (1,6±0,04) in Gr.2 (p<0,05) and general WOMAC index in Gr.1 was significantly lower than in Gr.2 (accordingly (22,8±0,3) and (36,5±0,8); p<0,05). In the next 6 months again patients in Gr.1 had less exacerbations (0,51±0,03) then patients in Gr.
