Christian Deininger (Salzburg / AT), Amelie Deluca (Salzburg / AT), Thomas Freude (Salzburg / AT), Herbert Tempfer (Salzburg / AT), Andrea Wagner (Salzburg / AT), Nadja Weißenbacher (Salzburg / AT), Florian Wichlas (Salzburg / AT), Andreas Traweger (Salzburg / AT)
Abstract text (incl. references and figure legends)
Particularly in osteoporotic bone, loosening of osteosynthesis material is a well-known problem. This leads to secondary fracture dislocation and non-healing. The aim of this study is to improve the stability of screws inserted into bone by adding Extracellular Vesicles (EVs) or Bone-Morphogenetic-Protein-2 (BMP-2) with alginate (Alg) as a carrier material.
Operations were performed on 30 rats. These were divided into 3 groups of equal size: Alg only, Alg EV, and Alg BMP-2. To analyze the osseointegration, a novel surgical procedure and biomechanical protocol were established. A diaphyseal fracture was created with a Gigli saw (0.66mm) and angular stable 5-hole plate osteosynthesis was used with four 1.5mm screws. The 4.0mm long proximal and distal screws were inserted monocortically in a 2.0mm hole that was too wide, so the screw had no contact area with the bone (Fig. 1). The hole was filled with the substances mentioned above. The 2 screws next to the osteotomy were placed bicortically to stabilize the fracture. After the endpoint (6 weeks postoperative), µ-CT, and a biomechanics pull-out test and a stiffness analysis were performed.
µ-CT scan shows significantly more Bone Volume/Tissue Volume in the BMP-2 group compared to the EV one (*p= 0.0203) (Fig. 2). The screw-bone contact area was significantly increased in the BMP-2 group compared to the EV group (**p= 0.0063), the contact area was significantly increased in the Alg only group compared to the Alg EV group (*p= 0.0438), too. The biomechanical pull-out test showed a significant increase of the maximal force of the BMP-2 group compared to the EV one (*p= 0.0240). The stiffness of the BMP-2 group was significantly higher compared to the Alg EV group (*p= 0.0414) and the Alg only group (*p= 0.0363).
The results indicate that the use of BMP-2 can improve the osseointegration of osteosynthesis materials. The use of EVs seems to have a rather negative effect on osseointegration in this animal model.
Disclosure: Do you have a significant financial interest, consultancy or other relationship with products, manufacturer(s) of products or providers of services related to this abstract? (If not, please enter "No" in the text field.)
No