Objective To evaluate the effects of 4 different epitendinous sutures on the tensile strength of the repaired tendons. Methods 40 plantar flexion deep tendons from pigs were divided into 4 groups randomly, with 10 in each group. After the core suture of Modifier Kessler was applied, 4 epitendinous sutures at different distances from suture sites to broken ends (4mm, 7mm, 10mm, 12mm) were used respectively in each group to repair the transected tendons. MTS Instron 4411 was used to test the repaired tendons. Tensile strengths at 2mm gap formation and at the peak were collected for statistical analyses by ANOVA. Results In this test, the tensile strength was found to increase with the distance from suture sites to broken ends. The tensile strength in the 4mm group was significantly lower than that in the others. There was little statistical difference between the other 3 groups. Conclusion Tensile strength of the repaired tendon tends to increase with the distance from suture sites to broken ends in epitendinous suture.

Objective To investigate changes in lengths of the wrist ligaments during wrist radioulnar deviation. Methods Six volunteers were included in the study. CT scans was used to detect the changes under different positions of the wrist in the volunteers. The wrists were scanned from the position of radial deviation of 20° to the one of ulnar deviation of 40° at an interval of 20°. The 3-dimensional carpal and distal radioulnar joint structures were reconstructed with customized software and chauges in length of the palmar and dorsal wrist ligaments in radioulnar deviation were computed. Results From wrist radial deviation to neutral position, the lengths of the radioscaphocapitate ligament, the long radiolunate ligament and the dorsal intercarpal ligament increased significantly (P ＜ 0.05), they increased (2.4±0.3) mm, (2.3±0.8) mm,(1.2±0.6) mm, (1.2±1.2)mm and (2.6±1.0) mm respectively. While from wrist ulnar deviation to neutral position, ulnocapitate ligament and the dorsal radiocarpal ligament increased significantly (P ＜ 0.05), they increased (0.8 ±0.6) nm and (1.0±0.5) mm respectively. Conclusion At wrist radial deviation, the radioscaphocapitate, long radiolunate and dorsal intercarpal ligaments are slack. At wrist ulnar deviation, the ulnocapitate ligament and the dorsal radiocarpal ligament are slack. These positions may be favorable to healing of these ligaments.