Factors affecting the features of platelet-rich plasma in patients with knee osteoarthritis.

Objective: The aim of this study was to present an analysis of platelet-rich plasma obtained from patients with knee osteoarthritis and reveal the factors affecting its features.

Methods: A total of 62 patients (mean age: 56.68 ± 7.13 years) with symptomatic knee osteoarthritis were included in this study. Age (years), gender, height (m), weight (kg), body mass index (kg/m2), duration of symptoms, smoking status, smoking index, general health status, and physical activity scores were recorded. Whole blood and platelet-rich plasma cell counts were performed with a hematology analyzer. White blood cell, red blood cell, and platelet counts were recorded. According to the dose of injected platelets, efficiency of the procedure, purity of platelet-rich plasma, and activation classification, dose of platelets, efficiency of the procedure (platelet recovery rate, %), and purity of the obtained platelet-rich plasma product (relative composition in platelets, %) were calculated. Correlation analysis between the features of platelet-rich plasma and the patient-related variables, including age, gender, body mass index, smoking status, smoking index, presence of other health conditions, physical activity scores, duration of symptoms, and pain levels, was performed.

Results: Dose of injected platelets, efficiency of the procedure, purity of platelet-rich plasma, and activation analysis showed that the dose of injected platelets was 3.25 billion, the efficiency of the process was 77%, and the purity rate of the platelet-rich plasma was 98.4%. Platelet-rich plasma platelet count was correlated with whole blood platelet count (r = 0.81, P < .001), whole blood white blood cell count (r = 0.39, P = .002), smoking status (r = 0.56, P = .03), smoking index (r = -0.63, P = .002), and the presence of hypertension (r = -0.31, P=.04). Platelet-rich plasma white blood cell and purity of platelet-rich plasma were correlated with the smoking status of the patients (r = 0.52, P = .01; r = 0.64, P = .003, respectively).

Conclusion: This study has demonstrated that high dose and very pure platelet-rich plasma with medium efficiency was yielded with this platelet-rich plasma preparation procedure; whole blood platelet count, the presence of hypertension, and the smoking status of patients affect the features of the obtained platelet-rich plasma.

Level of evidence: Level IV, Diagnostic Study.