In vitro cyclic tensile testing of combined peripheral and core flexor tenorrhaphy suture techniques

Early tenorrhaphy mobilization increases repair site strength and decreases adhesions. Preliminary unpublished data suggest that early active mobilization improves clinical outcome compared with traditional passive motion protocols. We loaded cadaver flexor profundus tendon repairs to 8.0 kg (78.4 N) for up to 5,000 cycles to simulate the loads and cycle number of our active flexor tendon rehabilitation protocol. 3-0 Ethibond (Ethicon, Somerville, NJ) and 6-0 Prolene (Surgi-pro; US Surgical, Norwalk, CT) were used for core and peripheral sutures, respectively. Four different groups were tested: 2-strand Tajima core suture with either a running interlocking (2R) or a Silfverskiöld cross-stitch (2S) peripheral suture and 4-strand Tajima plus horizontal mattress core suture with either a running interlocking (4R) or a Silfverskiöld peripheral suture (4S). Repairs failed in the suture midsubstance or at the knot. There was considerable variability within groups and no significant difference in the number of cycles to failure between the 2R, 4R, and 2S repairs, which failed after 2 +/- 2, 304 +/- 249, and 560 +/- 987 cycles, respectively. All 4S repairs were intact after 5,000 cycles. Our data suggest that flexor tenorrhaphy with the 4S repair can withstand the cyclic loads we estimate would be present during an active rehabilitation protocol.