Veronika Lehner (Gießen, DE), Dr. Henrik Werner Wagner (Gießen, DE), Prof. Dr. Thaqif El Khassawna (Gießen, DE), Ida Marie Heger (Gießen, DE), Pascal May (Gießen, DE), Andres Tiberius Rießle Fernandez-Tenllado (Gießen, DE), Dr. Ursula Sommer (Gießen, DE), Tim Ludwig Tüngler (Gießen, DE), Prof. Dr. Klaus Liefeith (Heilbad Heiligenstadt, DE), Dr. Michaela Noll (Esslingen, DE), Claudia Ortmann (Mörsdorf, DE), Dr. Jonas Wiedenmann (Würzburg, DE), Dr. Christoph Biehl (Gießen, DE), Prof. Dr. Katrin Susanne Lips (Gießen, DE)
Abstract text (incl. figure legends and references)
Treatment of osteochondral defects are still a challenge in the clinical situation of orthopedics and trauma surgery. Therefore, our BMBF funded consortium (FKZ 13XP5089) established new porous scaffolds of poly-((D,L)-lactide-ε-caprolactone)-dimethacrylat (LCM) by laser-assisted two-photon polymerisation that mimics the osteochondral region. Additionally, in one test group the pores were filled with biogel based on collagen for improved cellular migration. The present study aims to analyze the in vivo biocompatibility of biogel filled LCM compared to pure LCM scaffolds in an ovine model of osteochondral defect repair.
LCM scaffolds with 7 mm diameter and 10 mm height were filled with biogel prior to implantation into osteochondral knee defects in the distal femur of adult female sheep (n=5). Before surgery and at day 5, 15, 30, 60, and 90 after implantation, sera were collected and analyzed by C-reactive protein (CRP) and lactate dehydrogenase (LDH) assay. Synovial fluid was harvested of the operated as well as of the untreated knee on day 90 and extensively analyzed.
Before implantation, no significant difference were measured in CRP and LDH of sera in both groups. After insertion of LCM scaffolds, the CRP increased at the early time points and then decreased significantly to the late time points. Pure LCM scaffolds resulted in lower CRP concentrations in sera and synovial fluid whereas LCM+biogel scaffolds generated reduced LDH values. However, a higher LDH was found in synovia of operated compared untreated knee joint for both groups.
Filling with biogel reduced the degradation of LCM and therefore the production of lactate. However, implantation of LCM+biogel resulted in upregulated CRP values that indicate an increased inflammatory reaction that might either be a sign of foreign body reaction or first stage of physiological defect healing. Thus, detailed analyses of the explanted scaffolds and surrounding tissue are necessary for further interpretation.