title: A biomechanical assessment of repair versus nonrepair of sheep flexor tendons lacerated to 75 percent.
abstract: OBJECTIVE
  The benefit of repairing a 75% partial flexor tendon laceration remains controversial. The purpose of this study was to assess the degree of gap formation with and without repair when the 75% lacerated tendon is subjected to cyclic loading. Repair with only a peripheral suture was compared to that using a core and peripheral repair technique.
  
  
  METHODS
  Sixteen deep flexor tendons from sheep hind limbs were lacerated to 75% of the tendon diameter. The cut tendons were loaded for 100 cycles from 3 N up to 30 N and then back to 3 N, at a rate of 0.2 Hz. Gap formation was measured at 0 and 100 cycles. Tendons were then randomized into 2 repair groups of 8 each: group 1 was repaired with only a simple, running peripheral suture (6-0 polypropylene monofilament), whereas group 2 was repaired with a modified Kessler core suture (4-0 silicone-coated braided polyester) plus a peripheral suture (6-0 polypropylene monofilament). Repaired tendons were tested for 500 cycles, and the gap was measured at 0, 100, and 500 cycles. After cycling, gap was measured at 100 N load, and the peak loads were determined on static failure testing.
  
  
  RESULTS
  The 75% partially lacerated tendons had >2 mm gap at 100 cycles. This gap was significantly reduced by peripheral or peripheral plus core repairs (p < .001). There was no difference in gap formation between tendons with peripheral repair only and those with both peripheral and core repairs. Gap formation in repaired tendons remained <or=1 mm at 500 cycles. After cycling, neither gap formation at 100 N load or the peak loads on failure testing differed between the 2 repair groups.
  
  
  CONCLUSIONS
  There is a large gap when an unrepaired 75% partial laceration is cyclically loaded. This gap is significantly reduced with a peripheral repair whether or not a core suture is used.
authors.affiliation: Surgical and Orthopaedic Research Laboratories, University of New South Wales, Prince of Wales Hospital, Sydney, Australia.
authors.forename: Roger
authors.initials: R
authors.lastname: Haddad
authors.forename: Peter
authors.initials: P
authors.lastname: Scherman
authors.forename: Tim
authors.initials: T
authors.lastname: Peltz
authors.forename: Sean
authors.initials: S
authors.lastname: Nicklin
authors.forename: William R
authors.initials: WR
authors.lastname: Walsh
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D006614:Hindlimb; D022125:Lacerations / Q000601:surgery*; D011897:Random Allocation; D012756:Sheep; D013314:Stress, Mechanical; D013536:Suture Techniques; D013708:Tendon Injuries / Q000601:surgery*; D053656:Tenodesis / Q000379:methods*