Bioabsorbable suture anchor (co-polymer 85/15 D,L lactide/glycolide) implanted in bone: Correlation of physical/mechanical properties, magnetic resonance imaging, and histological response

A novel bioabsorbable suture anchor has been introduced for shoulder rotato r cuff surgical repair made of the co-polymer 85/15 D,L lactide/glycolide. Previous clinical reports on the use of this material in anterior cruciate ligament reconstruction have described intraosseous edema at various time i ntervals following implantation. The purpose of this study was to analyze t he implant's loss of physical properties and to correlate magnetic resonanc e imaging (MRT) finding with gross and histological observations at various time intervals after intraosseous implantation in the experimental animal. Six drill holes were made in the tibias of 11 dogs. The spherical implant was placed in 5 of the drill holes and the sixth was preserved as a sham co ntrol. The dogs were killed at 3, 4, 6, 9, 12, and 26 weeks for gross and m icroscopic inspection. Correlative MRIs were taken from the 4-, 12-, and 26 -week specimens. Gross inspection showed that the overlying soft tissue hea led to bone in 3 weeks. The implants were surrounded by new bone by 6 weeks . The implants maintained gross physical integrity for 6 to 12 weeks. Histo logically, there was minimal inflammatory response to the degrading implant . The implant site had been completely replaced by bone at 12 weeks, Correl ative MRI showed edema adjacent to the implant sites, but there was no corr elative inflammation or cyst formation through the time necessary for compl ete absorption of the implant. Correlative MRT identified and differentiate d the image of the intact and degrading implant.