25dkou204 10.3205/25dkou204 urn:nbn:de:0183-25dkou2047 Meeting Abstract Kienzle Kienzle Arne A

Charité Universitätsmedizin, Berlin, Deutschland

author Qiao Qiao Renqiu R

Charité Universitätsmedizin, Berlin, Deutschland

author Mehl Mehl Julia J

Charité Universitätsmedizin, Berlin, Deutschland

author Donner Donner Stefanie S

Charité Universitätsmedizin, Berlin, Deutschland

author Damm Damm Philipp P

Charité Universitätsmedizin, Berlin, Deutschland

author Duda Duda Georg G author Perka Perka Carsten C author Kirschbaum Kirschbaum Stephanie S

Charité Universitätsmedizin, Berlin, Deutschland

author German Medical Science GMS Publishing House

Düsseldorf

610 20251031 engl This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). M0634 204 Deutsche Gesellschaft für Orthopädie und Unfallchirurgie Deutsche Gesellschaft für Orthopädie und Orthopädische Chirurgie Deutsche Gesellschaft für Unfallchirurgie Berufsverband für Orthopädie und Unfallchirurgie Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2025) Poster | Infektionen Berlin 20251028 20251031 AB29-4268 TextObjectives and questions: Reinfection risk remains significantly elevated after periprosthetic joint infection (PJI) of the knee, yet the underlying mechanisms are poorly understood. The prevailing assumption that bone and soft tissues recover post-explant revision surgery has been challenged by evidence suggesting persistent pathological changes. This study evaluates whether alterations in soft tissue vascularization and fibrosis contribute to PJI pathology and the heightened reinfection risk.Material and methods: Soft tissue samples were analyzed from 65 patients undergoing joint replacement surgery, including those with primary knee osteoarthritis (control, n=19) and those undergoing two-stage surgical interventions for PJI (explantation, n=20; reimplantation, n=26). Histological assessment measured vessel count, density, and fibrosis (Sirius red, Masson). Immunohistochemical staining evaluated cell proliferation. Molecular analyses quantified angiogenesis-related gene expression (PDGFB, MIG, MMP9, HIF-1A, ANGPT-2, VEGFA, PDGFA, FN1, FGF2) and endothelial markers (MMP-2, PECAM-1) using PCR.Results: PJI samples showed significant vascular and fibrotic changes. Vessel number and density were elevated at explantation (+29.6% and +42.2%) and reimplantation (+58.4% and +41.4%). Cell proliferation rates increased (+32.6% at explantation, +42.9% at reimplantation). Fibrosis was significantly increased at explantation (mean diff. -19.15, p=0.0053) and reimplantation (mean diff. -21.10, p=0.0014). PDGFB expression increased at reimplantation (2.47-fold), MIG at both explantation (5.74-fold) and reimplantation (3.70-fold), MMP9 at explantation (2.34-fold) and reimplantation (6.67-fold). HIF-1A and ANGPT-2 increased modestly, VEGFA, PDGFA, FN1, and FGF2 decreased. No significant changes in MMP-2 or PECAM-1.Discussion and conclusions: These findings highlight vascular and fibrotic remodeling in infected periprosthetic soft tissues. Increased vessel density, fibrosis, and angiogenesis-related changes create a microenvironment favoring reinfection. We postulate that concurrent vascularization and fibrosis impair immune surveillance, promoting reinfection despite surgical intervention. 0 0 0 0