Single side locking on the opposite of the modified Kessler tendon repair prevents gap formation and suture pull-out: a biomechanical evaluation in sheep tendons.

OBJECTIVES: Locking loops are invented to prevent pull-out complication during early active rehabilitation after flexor tendon repair. This study compares the mechanical properties of the side-locking modified Kessler repairs with four- and two- side locking points.

MATERIALS AND METHODS: Twenty fresh flexor digitorum profundus tendons of the healthy adult sheep forelimbs were sutured by the two-strand modified Kessler with the side-locking loop technique (group A: four locking points), and by the two-strand modified Kessler repair method with a side locking knot on the opposite corners of the repair (group B: two locking points). To assess the mechanical performance of the repairs, the tendons were subjected to a linear non-cyclic load-to-failure test using a material testing machine. Outcome measures included the 2.0 mm gap force at the tendon ends, the ultimate forces and the mode of failure.

RESULTS: The mean value for the 2.0 mm gap strength was 19.2+/-1.4 for group A and 19.3+/-1.9 for group B. The mean value of the failure strength was 33.1+/-2.6 for group A and 29.8+/-3.2 for group B. Regarding the 2.0 mm gap strength between the tendon ends, no significant difference was observed between the two groups. There were statistically significant differences in failure strengths of the two groups (p=0.019). As regards the mode of failure, no suture pull-out was observed. All the specimens failed due to suture breakage at the repair site.

CONCLUSION: Results of this study revealed that gap formation and suture pull-out can be prevented using single side locking points on the opposite corners of the modified Kessler repair.