Evaluation of the degradation of two bioabsorbable interference screws: an in-vivo study in sheep

Abstract

Purpose: To evaluate in-vivo degradation of two bioabsorbable interference screws. Methods: Twenty-two crossbred Santa Inês ewes were used. A poly-DL-lactide (PDLLA) screw (70%/30%) was inserted in the right pelvic limb, and a PDLLA screw (70%) + β-tri-calcium phosphate (β-TCP) (30%) in the left pelvic limb. Animals were euthanized at one, four, seven and a half and 18 months after surgery.Plain radiography, computed tomography (CT), microCT, and histological analysis were accomplished. Results: PDLLA screw was hypodense at all evaluation moments, but with progressive density increase along the central axis, whereas PDLLA/β-TCP was initially hyperdense and progressively lost this characteristic. No adverse reactions were observed on histological evaluation. Conclusions:The inclusion of β-TCP favors screw degradation since the PDLLA/β-TCP screws evidenced a more intense degradation process than the PDLLA screws at the last evaluation. PDLLA screws showed higher bone production, evident around the screw thread, inside the lateral perforations, and in the central canal, whereas the PDLLA/β-TCP screws presented less bone tissue at the implantation site.

Bone Incorporation of a Poly (L-Lactide-Co-D, L-Lactide) Internal Fixation Device in a Rat’s Tibia: Microtomographic, Confocal LASER, and Histomorphometric Analysis

“…Surgery to remove metallic materials can cause tissue trauma because of the need to detach soft tissues [50]. In the present study, we found that, at 28 and 42 days, mineral apposition was stable, and at 42 days, the BIC was greater in both areas (cortical and cancellous areas), in line with previously published studies [51][52][53]. The results demonstrated the stability of the devices in the bone, demonstrating that the fixation device was incorporated.…”

Anterior Cruciate Ligament Reconstruction in a Translational Model in Sheep Using Bio- Integrative Mineral Fiber-Reinforced Screws

“…Their ndings indicated 5% of multiloculated pretibial cysts with histiocytic in ltrate around the PLLA debris with surrounding acellular cystic material 2-3 years following implantation 45 . These ndings can appear years following initial implant placement [28][29][30]46 . Drogset et al reported osteolysis around PLLA screws in 16% of ACLR patients 47 .…”

“…The "early" shortcomings, experienced around the time of surgery and include intraoperative screw breakage, loss of xation, graft slippage, and screw migration 18,28 . The "late" complications are usually associated with an imbalanced degradation response re ected by in ammatory reactions leading to accelerated or incomplete absorption, joint effusion, bone tunnel widening and encapsulation 18,24,[28][29][30][31] . Additional reported material-related complications are cyst or abscess formation, intraarticular granulomas and adverse foreign body reactions which might result in osteolysis, synovitis and rarely, systematic allergic response 29,32 .…”