VPB0897 - Platelet indices at the titanium rod implantation in rabbit femur

Background: Blood loss, venous thromboembolism, aseptic fragility of prosthesis components and periprosthetic infection are the most severe complications encountered in major joint replacements (MJR). Platelets are the first cells which contact injured tissues and implant surface, they catalyze stable clot formation, stimulate regeneration and take part in antimicrobial protection.

Aims: To study the features of platelet parameters dynamics depending on its initial state during titanium rod implantation in rabbit femur.

Methods: The experiment included 20 Chinchilla rabbits. Parameters: platelet count, MPV, PDW, PCT, P-LCR (Sysmex XN-1000), ADP aggregation (Chrono-Log 700) were determined before surgery, 1 day and 8 weeks after surgery. Animals were divided into 2 groups according to the score number calculated using preoperative platelet parameters (Table 1). HPI group (high platelet index) included 8 rabbits with 5-8 scores. In LPI group (low platelet index) group - 8 rabbits with 9-11 scores. Titanium rod (0.2x0.6 cm) was implantated according to press fit principle in rabbit femur. Animals were withdrawn from the experiment 8 weeks after surgery. The study was approved by Local Ethics Committee of the Ural State Medical University in accordance with national and EU regulations. Statistical analysis was performed using "Statistica" software package.

Results: Platelet parameters before orthopedic surgery, 1 day and 8 weeks after titanium rod implantation are shown in Figure 1. Before surgery, the HPI group had significantly higher values of platelet count, MPV, and ADP-induced aggregation than the LPI group. In postoperative period, the values of these indicators were also higher in the HPI group in comparison to the LPI group.

Conclusion(s): The number of platelets, cell volume, aggregation activity in postoperative period depend on its initial parameters. In this regard the possibility of predicting the functional activity of platelets and the success in repair process during major orthopedic operations would be helpful.