Biomechanical study of a newly developed continuous double knots technique compared with the 4-strand double-modified Kessler technique for flexor tendon repair

PURPOSE: In this study we compare the biomechanical properties of a novel suture technique that we developed called the continuous double knots technique for repairing flexor tendon injuries with the standard 4-strand double-modified Kessler technique. METHODS: This was an experimental study. Eighty porcine flexor digitorum profundus tendons were harvested and divided randomly into two groups of 40. The first group (N = 40) was repaired using the 4-strand double modified Kessler technique and the second group (N = 40) was repaired using our new continuous double knots technique. The two groups were randomly divided and the ultimate failure load (n = 20) and cyclic testing to failure (n = 20) were compared. RESULTS: The mean ultimate failure load was 25.90 ± 7.11 (N) and cyclic testing to failure 88 ± 47.87 (cycles) for the 4-strand double modified Kessler technique and 34.56 ± 6.60 (N) and 189 ± 66.36 (cycles) for our new continuous double knots technique. The T-test revealed a significant difference between the 2 techniques (p < 0.05). In terms of biomechanical properties in tendon repair, the continuous double knots technique group had a higher tensile strength than the 4-strand double-modified Kessler technique group. There were also significant differences between the ultimate failure load and cyclic testing to failure for the flexor tendon sutures. CONCLUSIONS: The continuous double knots technique suture technique had significantly higher maximum tensile strength and cyclic testing than the 4-strand double modified Kessler technique in an in vitro study, and in thus an optional technique for flexor tendon repair.