Failure strengths of suture versus biodegradable arrow for meniscal repair: an in vitro study

Advances in our understanding of meniscal function and consequences of menisectomy have spawned meniscal repair techniques that yield success rates approaching 90% in properly selected patients. Biodegradable implants have been fashioned for meniscal fixation to simplify the technique and minimize neurovascular complications. We performed the current study to determine the in vitro biomechanical behavior of the BIOFIX Meniscal Arrow, a polylactic acid tack developed for meniscal repair. Eight pairs of menisci were harvested from cadaveric knees kept frozen before testing. Peripheral vertical tears were created in the posterior horn of all menisci, and each was subsequently repaired using a vertical loop suture of 2-0 Ethibond and a Meniscal arrow. Ultimate load to failure of each method was determined on a Hounsfield H25KM Universal Testing machine. The mean failure load for the suture group was 58.3 N compared with the Arrow group mean of 29.6 N (P < .001). All sutures failed by rupture at the knot but did not pull through the meniscus. All but one of the arrows failed by pulling out of the meniscus. The Arrows also permitted gapping at the repair site at considerably lesser loads than the sutures subject to strain. The concept of a biodegradable tack is appealing. Vertical loop sutures should be the standard by which their biomechanical performance is judged. We suggest modifications to the Arrow design that could enhance the fixation strength of this implant.