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Conflicts of interest and sources of funding: none declared. Supplemental digital content is available for this article. FIGURE 1. Medial sural artery perforator flap is a reliable choice for repairing small to medium-sized defects of the knee. A, W e read with interest the recent article by Hersant et al in the journal. Encouraged by a retrospective study in which platelet-rich plasma (PRP) (Harvest's PRP) injection combined with radiotherapy was applied on wound after keloid resection and based on the theory that cellular composition influenced the concentrations of growth factors and cytokines and thus PRP's biological effects, the authors applied PRP (Regen's PRP) on surgical excision in the treatment of keloids refractory to conventional treatments and achieved a healing rate of 53%. Some confusion is likely because different suppliers and authors use the same nomenclature for distinct PRP products. In the article, the authors cited several previous researches to support and explain the beneficial effect of Regen's PRP on keloids, but these researches focused on different autologous blood products, including Harvest's PRP, PRGF-Endoret's PRP, PRP produced in laboratory, and PRP releasate (the supernatant after concentration during PRP production by GPS III System) instead of PRP itself. These products were prepared by different procedures, having different cellular composition, and one of them was not PRP at all. As the authors repeatedly mentioned that PRP's composition influenced its biological effects, using PRP with different concentrations of growth factors and cytokines to explain the effect of another PRP is not acceptable and persuasive. Moreover, the authors claimed that Regen's PRP was a leukocyte-reduced PRP and explained its effect on keloids based on this property. But Regen's PRP in fact is contrarily a leukocyte-rich PRP. In another research also studying PRP and keloid resection, undermining was performed after keloid resection to mobilize the flaps for minimal skin tension closures, dermal layer was secured by absorbable monofilament sutures, and Dermabond and skin strips were applied on the sutured skin. All these procedures were taken to minimize skin tension and prevent keloid relapse, whereas in this study the closure consisted only of separate everting suture plane with nonabsorbable nylon sutures. Either to