Biomechanical changes in the early period of flexor tendon repair: an experimental study / 中华骨科杂志

ABSTRACT

Objective To investigate biomechanical characteristics of flexor profundus tendon repaired by modified Kessler or Tsuge technique in the early of postoperative period, and to discuss the feasibility of using two techniques in flexor tendon repair in order to proceed early active or passive mobilization protocols. Methods 42 Sanhuang cocks were randomly divided into two groups. The second and fourth flexor digitorium profoundus tendons of cocks were severed at the middle phalanx transversely and repaired by modified Kessler or Tsuge technique respectively, postoperative plaster cast immobilization was maintained for 3 weeks. The repaired tendons were harvested at 7 time intervals-immediately after repair, 1, 4, 7, 10, 14, 21 days after operation and stored at  20 ℃ in a refrigerator until biomechanical test. A tensile strength-elongation curve was obtained for each tendon sample. Biomechanical parameters including tensile strength of rupture and elongation ratio of rupture were calculated from the curve automatically by testing machine. SPSS software was used for statistical analysis. Independent-samples t test for inter-group comparison; One way ANOVA and SNK q test for inter-group comparison. Results The tensile strength of rupture dropped to the lowest level between 10th and 14th day and resumed its original level immediately after repair at 21st day in modified Kessler group; while in Tsuge group, it decreased at 10th day, then slowly rised up at 14th day but still didnt reach the original level at 21st day. There was no significant difference between two repair methods after 4th day after operation. The elongation ratio of rupture was lowered significantly since 7th day in modified Kessler method, but 4th day in Tsuge method and decreased consistently until 3 weeks postoperatively. There was no significant difference between the two suture methods at any time-intervals. Conclusion The rather high biomechanical characteristics of Tsuge method loses quickly in the early period of tendon healing and resumes slowly; Modified Kessler method maintains its biomechanical properties at all time-intervals except 10th day.