THE IN-VIVO HISTOLOGY OF AN ABSORBABLE SUTURE ANCHOR - A PRELIMINARY-REPORT

Suture anchors are playing an increasingly important role in attaching tendons or ligaments to bone. Anchors are usually made of metallic or other nonbioabsorbable materials. The development of an absorbable su ture anchor would provide a valuable tool for the surgeon; this charac teristic would minimize the problems of anchor loosening, migration, i nterference with imaging studies, and the potential requirement for la ter implant removal. This study evaluated the in vivo histological res ponse over time of the first generation Arthrex Expanding Suture Plug (ESP) (Arthrex Inc, Naples, FL). Suture anchors threaded with nonabsor bable No. 2 braided polyester sutures were implanted into ram femurs a nd removed at various intervals over a period of 12 weeks. After prepa ration, histological study showed a gradual healing response in the bo ne tract. There was no evidence of an inflammatory infiltrate or forei gn-body reaction during the 12 weeks of implantation. A normal bone ca llus appeared at the insertion tunnel site consistent with a fracture- healing response. Later, a fibrous membrane appeared at the junction o f the implant and the bone tunnel. Over the 12 week interval, there wa s a decrease in osteoblastic activity and the appearance of cavernous vascular spaces in the superficial portions of the membrane near the p eriosteum. The ESP anchor composed of poly-L-lactic acid was well tole rated in the in vivo setting. Throughout the study, no substantial acu te, chronic, or foreign-body reaction was observed. These observations are consistent with the expected in vivo behavior of poly-L-lactic ac id. There is no reason to believe that the ESP composed of poly-L-lact ic acid should cause a foreign body reaction.