Failure strength of a new meniscus arrow repair technique: biomechanical comparison with horizontal suture.

A new method for arthroscopic all-inside repair of vertical meniscus lesions by use of a biodegradable fixation device ("meniscus arrow") has been developed, including a set of cannulas for easy insertion via standard arthroscopic portals. The technique is described. A study to test the fixation properties was performed in the laboratory. Twenty-four fresh frozen bovine medial menisci were defreezed and divided into three groups. In all menisci an artificial vertical lesion was created with a scalpel 3mm from the peripheral rim. Repair in group I was done with a single horizontal Maxon-O suture using an Acufex double-barrel cannula (Acufex Meniscal Stitcher; Acufex Microsurgical, Norwood, MA). A knot was tied on the capsular side. Repair in group II was made with one 13 mm Biofix Meniscus arrow (Bioscience Ltd, Tampere, Finland). In group III repair was performed like in group II but the menisci were incubated in isotonic saline at 21 degrees C for 24 hours before testing. Menisci in group I and II were tested within 3 hours after defreezing. Prior to testing total separation of central and peripheral part of meniscus was performed. Thus only the repair site was tested. Pull-out tests to failure were made in a computer-based Nene M5 testing machine with a cross-head speed of 5 mm/min. Median failure load in group I: 49 N (range 43 to 77 N), in group II: 53 N (range 42 to 65 N) and in group III: 54 N (range 35 to 74 N). No statistically significant differences in failure load was found between the groups. Thus initial failure strength for arrow-repaired bovine menisci is comparable to that of a horizontal suture.