Repair of flexor digitorum profundus tendon avulsions from bone: An ex vivo biomechanical analysis

Avulsions or distal transections of the flexor digitorum profundus tendon are typically repaired by direct suture of the tendon stump to the distal phalanx. The optimal repair technique to withstand in vivo rehabilitation forces is unknown. Our objective was to determine the time-zero tensile mechanical properties of 4-strand tendon-bone repair site constructs performed with 3-0 and 4-0 sutures and with modified Kessler and modified Becker grasping techniques. We hypothesized that the 3-0 modified Becker grasping suture technique not described previously for the reattachment of tendon to bone would show improved biomechanical properties compared with the 4-0 or modified Kessler techniques. All modified Kessler repairs failed by suture pullout from the tendon, whereas all modified Becker repairs failed by rupture of the suture at the tendon-bone junction. Although the 3-0 modified Becker repair group showed greater ultimate force then the other groups (p < .01), tendon-bone gap observed did not differ markedly between Becker or Kessler groups. Neither suture caliber nor repair technique had a notable effect on strain at 20-N force, suggesting that early gap formation at the tendon-bone repair site may occur regardless of technique.