Background:Platelet-rich plasma (PRP) is one of the most frequently used orthobiologic products for the injection treatment of patients affected by knee osteoarthritis (OA). Some preliminary evidence supports the influence of platelet concentration on patients’ clinical outcomes.Purpose:To analyze if platelet concentration can influence the safety and clinical efficacy of PRP injections for the treatment of patients with knee OA.Study Design:Cohort study; Level of evidence, 3.Methods:This study consisted of 253 patients with knee OA (142 men, 111 women; mean ± SD age, 54.8 ± 11.4 years; Kellgren-Lawrence grades 1-3) who were treated with 3 intra-articular injections of 5 mL of autologous leukocyte-rich or leukocyte-poor PRP. All patients were prospectively evaluated at baseline and at 2, 6, and 12 months. Patients were clinically assessed thorough the Knee injury and Osteoarthritis Outcome Score (KOOS) subscales and the International Knee Documentation Committee (IKDC) Subjective score. Platelet concentration was correlated with clinical outcome. Further analysis was performed by stratifying patients into 3 groups (homogeneous for OA severity) based on platelet concentration (high, medium, and low). All complications and adverse events were reported, as well as failures.Results:An overall statistically significant improvement in all clinical scores was documented from baseline to each follow-up evaluation. Platelet concentration positively correlated with clinical outcome. KOOS Pain improved more with higher platelet concentration at 2 months ( P = .036; rho = 0.132), 6 months ( P = .009; rho = 0.165), and 12 months ( P = .014; rho = 0.155). The same trend was shown by the other KOOS subscales and by the IKDC Subjective score, as well as by the comparison of the groups of high-, medium-, and low-platelet PRP. The highest failure rate (15.0%) was found in the low-platelet group as compared with the medium-platelet group (3.3%) and the high-platelet group (3.3%). No differences were observed among the 3 groups in terms of adverse events.Conclusion:This study demonstrated that platelet concentration influences the clinical outcome of PRP injections in knee OA treatment. PRP with a higher platelet concentration provides a lower failure rate and higher clinical improvement as compared with PRP with a lower platelet concentration, with overall better results up to 12 months of follow-up in patients with knee OA.

中文翻译：

---

血小板浓度对膝骨关节炎富血小板血浆注射临床结局的影响


背景： 富血小板血浆 （PRP） 是膝骨关节炎 （OA） 患者注射治疗最常用的骨科产品之一。一些初步证据支持血小板浓度对患者临床结果的影响。目的： 分析血小板浓度是否会影响 PRP 注射治疗膝关节 OA 患者的安全性和临床疗效。研究设计： 队列研究;证据水平， 3.方法： 本研究包括 253 例膝关节 OA 患者 （142 例男性，111 例女性;平均 ± SD 年龄，54.8 ± 11.4 岁;Kellgren-Lawrence 1-3 级）接受 3 次关节内注射 5 mL 富含白细胞或缺乏白细胞的 PRP 治疗。所有患者在基线和 2 、 6 和 12 个月时都进行了前瞻性评估。通过膝关节损伤和骨关节炎结果评分 （KOOS） 分量表和国际膝关节文献委员会 （IKDC） 主观评分对患者进行临床评估。血小板浓度与临床结局相关。通过根据血小板浓度 （高、中和低） 将患者分为 3 组 （OA 严重程度同质） 进行进一步分析。报告了所有并发症和不良事件以及失败。结果： 从基线到每次随访评估，所有临床评分的总体统计学显着改善。血小板浓度与临床结局呈正相关。在 2 个月 （P = .036;rho = 0.132）、6 个月 （P = .009;rho = 0.165） 和 12 个月 （P = .014;rho = 0.155） 时，血小板浓度越高，KOOS 疼痛改善得更多。 其他 KOOS 分量表和 IKDC 主观评分以及高、中、低血小板 PRP 组的比较也显示了相同的趋势。与中血小板组 （3.3%） 和高血小板组 （3.3%） 相比，低血小板组的失败率最高 （15.0%）。3 组在不良事件方面未观察到差异。结论： 本研究证明，血小板浓度影响膝关节 OA 治疗中 PRP 注射的临床结局。与血小板浓度较低的 PRP 相比，血小板浓度较高的 PRP 提供更低的失败率和更高的临床改善，膝关节 OA 患者在长达 12 个月的随访中总体结果更好。