Ab1209 an investigation of the variables influencing platelet-rich plasma features in individuals with knee osteoarthritis

Background Platelet Rich Plasma (PRP) has drawn great interest as a regenerative adjunct therapy, and it is increasingly used in management of knee osteoarthritis (OA). The primary goal of PRP injections is to deliver a higher concentration of platelets to the target area than blood circulation does. The features and content of the injected substance are vital when evaluating the effectiveness of PRP. Objectives The objective of this study was to investigate the factors affecting the features of PRP in patients with knee OA. Methods Potential volunteers with diagnose of symptomatic knee OA were included if they had knee pain greater than 3 points on 11-point numerical pain rating scale. Exclusion criteria were i) lower hemoglobin count than 15g/dL, ii) ongoing anticoagulation therapy, iii) using non-steroidal anti-inflammatory drugs in previous 3 weeks before the participation, iv) previous operation in affected knee v) active infection or malignancy, and vi) impaired cognition. To perform complete cell counts for both whole blood and PRP, 20 ml of the whole blood was drawn from the ante-cubital vein of the patients under sterile conditions. PRP was prepared using a commercially available kit, tubes contains 3.20% concentrated 0,1M of sodium citrate to block the coagulation. After phlebotomy, the tubes were placed swing-out rotor centrifuging device and were centrifuged at 830g for 4 minutes. A correlation analysis was performed between the features of PRP and the patient-related variables, including age, gender, BMIs, smoking status, presence of other diseases, physical activity scores, duration of symptoms, and pain levels. Pearson’s correlation coefficient, point bi-serial correlation, and paired sample t test were performed; alpha level was set at 0.05 in all analyses. Results A total of 62 patients (mean age: 56.68 ± 7.13 years) were included in the analysis. The dose of injected platelets was 3.25 billion, efficiency of the process was 77%, and the purity rate of the PRP was %98.4. These results indicated “high dose (B)”, “medium platelet recovery rate (B)”, and “very pure (A)”. PRP platelet count was correlated with whole blood platelet count (r=0.81, p<0.001), whole blood WBC count (r=0.39, p=0.002), smoking status (r=0.56, p=0.03), smoking index (-r=0.63, p=0.002), and the presence of hypertension (r=-0.31, p=0.04). PRP WBC and purity of PRP were correlated with smoking status of the patients (r=0.52, p=0.01; r=0.64, p=0.003, respectively). In addition, smoking index for current smokers was shown a good correlation with PRP WBC (r=0.57, p=0.02) and a fair correlation with purity of PRP (r=0.35, p=0.04). Conclusion High dose and very pure PRP with medium efficiency was yielded with this PRP preparation procedure. Whole blood platelet count, the presence of hypertension, and the smoking status of the patients can affect the features of the yielded PRP in patients with OA. Considering these factors into account in the clinical decision is important for determining whether PRP is an option in the management of patients with knee osteoarthritis. These results may serve as a guide in terms of patient selection and avoiding unnecessary injections and their associated costs. References [1]Everts P, Onishi K, Jayaram P, et al. Platelet-Rich Plasma: New Performance Understandings and Therapeutic Considerations in 2020. Int J Mol Sci. 2020;21(20):7794. [2]Kon E, Di Matteo B, Delgado D, et al. Platelet-rich plasma for the treatment of knee osteoarthritis: an expert opinion and proposal for a novel classification and coding system. Expert opinion on biological therapy. 2020;20(12):1447-1460. [3]Chen P, Huang L, Ma Y, et al. Intra-articular platelet-rich plasma injection for knee osteoarthritis: a summary of meta-analyses. J Orthop Surg Res. 2019;14(1):385-385. [4]Magalon J, Chateau AL, Bertrand B, et al. DEPA classification: a proposal for standardising PRP use and a retrospective application of available devices. BMJ open sport & exercise medicine. 2016;2(1):e000060. Acknowledgements: NIL. Disclosure of Interests None Declared.