Aim: The most common risk associated with intradiscal injection of platelet-rich plasma (PRP) is discitis with Cutibacterium acnes. It is hypothesized that antimicrobial activity of PRP can be enhanced through inclusion of leukocytes or antibiotics in the injectate. Materials & methods: Multiple PRP preparations of varying platelet and leukocyte counts were co-cultured with C. acnes with or without cefazolin, with viable bacterial colony counts being recovered at 0, 4, 24 and 48 hours post-inoculation. Results: A direct correlation between C. acnes recovery and granulocyte counts were observed. Conclusion: We observed the greatest antimicrobial activity with the leukocyte-rich, high platelet PRP preparation combined with an antibiotic in the injectate. However, cefazolin did not completely clear the bacteria in this assay.

Purpose This study aimed to assess clinical outcomes following intradiscal injections of higher-concentration (> 10 ×) platelet-rich plasma (PRP) in patients with chronic lumbar discogenic pain and to compare outcomes with a historical cohort. Methods This retrospective study included 37 patients who received intradiscal injections of higher-concentration (> 10 ×) PRP and had post-procedure outcomes data (visual numerical scale pain score, Functional Rating Index [FRI], and NASS Patient Satisfaction Index). Outcomes were compared to a historical cohort of 29 patients who received intradiscal injections of < 5X PRP. Results Pain and FRI scores significantly improved by 3.4 ± 2.5 and 46.4 ± 27.6, respectively, at 18.3 ± 13.3 months following intradiscal injections of > 10 × PRP (p < 0.001). These improvements were greater than those reported by the historical cohort (1.7 ± 1.6 and 33.7 ± 12.3; p = 0.004 and 0.016, respectively). Additionally, the satisfaction rate was higher in patients receiving > 10 × PRP compared to those receiving < 5 × PRP (81% vs. 55%; p = 0.032). Conclusions Findings from this study suggest that clinical outcomes can be optimized by using PRP preparations that contain a higher concentration of platelets. Further research is needed to continue to optimize the composition of PRP used to treat patients with lumbar disc disease.

Introduction: Point-of-care analyses of platelet-rich plasma (PRP) are not routine in the orthopedic regenerative medicine field. Therefore, many physicians rely on the manufacturer's reported content for commercial preparation kits. This contributes to a knowledge gap between injectate content and patient outcome.Objective: To assess whether the EmCyte PurePRP II 60-mL preparation kit returns PRP content that meets the manufacturer's expectations when used during routine clinical care for a heterogenous patient population, and to determine whether a change in PRP yield volume affects injectate content. Protocol A (exclusion of granulocytes and low hematocrit) and Protocol B (inclusion of granulocytes and higher hematocrit) were evaluated. Design: Retrospective review. Setting: Private practice. Participants: One hundred five patients (118 preparations) treated for orthopedic conditions over an 8-month period via PRP injection. Thirteen patients had two independently made preparations on different treatment days that qualified for analysis. Interventions: Not applicable. Main Outcome Measures: Complete blood count (absolute counts and calculated fold enrichment from baseline of platelets, white blood cells, red blood cells, granulocytes, lymphocytes, monocytes; and hematocrit levels). Confounding variables included age, gender, and preparation yield volume. Results: During routine clinical use, the cellular content of both Protocols A and B met or exceeded the manufacturer's expectations of platelet enrichment and granulocyte inclusion or exclusion. Hematocrit values were slightly higher than anticipated from Protocol A preparations. The modification of yield volume from 7 to 4 mL led to a significant difference in platelet enrichment without affecting absolute cell counts (2.88; 95% confidence interval [CI] 1, 4.76; P = .003). Both gender and age moderately affected the level of platelet enrichment from baseline but did not significantly affect absolute platelet counts. Conclusion: In the absence of widespread characterization, confirming the variation in commercial PRP kits during clinical use is crucial.