Suture slippage in knotless suture anchors as a potential failure mechanism in rotator cuff repair.

Purpose: To quantify the strength of suture fixation of knotless suture anchors in relation to the anchors' pullout strength and to compare these results with the static friction between different sutures and anchor materials.

Methods: Suture slippage within the anchor and pullout strength of 4 different knotless suture anchor models were assessed in a bovine bone model. Furthermore, the peak force before onset of slippage of different sutures trapped between increasingly loaded 4-mm rods made of commonly used anchor material (polyetheretherketone, poly-L-lactide acid, metal) was assessed.

Controlled release of tetracycline from biodegradable beta-tricalcium phosphate composites.

For use in the prevention of bone infections, a novel controlled release system composed of beta-tricalcium phosphate (TCP) granules with biodegradable coatings incorporating the antibiotic drug tetracycline (TC) was developed. Six formulations using poly(D,L-lactide) and poly(D,L-lactide-co-glycolide) as coating materials to incorporate TC were prepared and tested in vitro and in vivo. Release of TC from TCP composites was dependent on the biodegradability of the used polymers and on physical-chemical interactions of TC with the polymer materials.

Influence of test temperature and test speed on the mechanical strength of absorbable suture anchors.

Purpose: Absorbable implant materials offer various advantages but are mechanically far weaker than metals. Despite known temperature dependence of the biomechanical properties of these materials, mechanical testing has almost exclusively been performed at room temperature in the literature. In this study, the difference in mechanical performance at room and body temperature was assessed in vitro at different test speeds.

Mechanical testing of absorbable suture anchors.

Purpose: Absorbable suture anchors offer great advantages but are made of mechanically weak material. The weakest link in the fixation of soft tissue to bone may therefore be the anchor itself. In this study, several commercially available anchors were mechanically tested in vitro.

Non-destructive three-dimensional evaluation of a polymer sponge by micro-tomography using synchrotron radiation.

X-ray micro-tomography, a non-destructive technique is used to uncover the complex 3-D micro-architecture of a degradable polymer sponge designed for bone augmentation. The measurements performed at HASYLAB at DESY are based on a synchrotron radiation source resulting in a spatial resolution of about 5.4 microm.

pH-stabilization of predegraded PDLLA by an admixture of water-soluble sodiumhydrogenphosphate--results of an in vitro- and in vivo-study.

Aim of the study was to examine if the addition of buffering sodiumhydrogenphosphate to poly(D,L)lactide(PDLLA) would stabilize the pH-value in the in vivo environment of implanted material and whether this improves its biocompatibility. The material was predegraded just to the point of viscous disintegration to test the PDLLA in the moment of its most aggressive effect on the surrounding tissue. Racemic amorphous PDLLA was injection-molded with or without the admixture of 1 mol NaP per 100 mol lactate, the degradation product of PDLLA (=1 mol%) to form 20mm x 3 mm x 2mm rods.