Trapezium

Repaired tendons were moistened with wet gauze prior to testing; all were subjected to linear load-to-failure testing using a tensile test machine (AG-I 10kN; Shimadzu Corp., Kyoto, Japan) (
Fig. 3). The force transducer of the machine was connected to the upper clamp. The force was recorded with a specialized software program (TRAPEZIUM; Shimadzu Corp., Kyoto, Japan). The tendon ends were tightly gripped in the upper and lower clamps. The initial distance between the clamps was 5 cm. A preload of 1 Newton (N) was applied before loading evaluation. The overhead crossbar connected to the upper clamp was advanced at a constant speed of 25 mm/min. The preload and the tendon pull rate simulated the loading of a tendon during active finger flexion.
8
The distance between the stumps was monitored by a video camera that had been vertically mounted at the level of the tendon repair site. The pulling force was continuously recorded. Any force that produced gaps evident on the monitor was recorded on the display board; each such force was considered an initial gap force. Any force separating the tendon stumps by 2 mm was recorded as a 2-mm gap formation force. An external observer recorded the initial and 2-mm gap forces. The tendons were pulled until complete pullout or rupture of the sutures occurred. The ultimate strength of the repair was the peak force recorded during the test.

The corneal strips were clamped vertically in the tongs of an electronic universal testing machine (Shimadzu Corporation) with the sclera and corneoscleral tissue both held in the tongs at both ends. The tensile strain test was run at 2 mm/min the initial strain loading to 0.05 N, with the length of the corneal trips between both tongs recorded as the initial length (Fig. 1). The elastic modulus was calculated using the software included with the testing machine (Trapezium; version 1.5.1; Shimadzu Corporation).

A uniaxial tensioning apparatus with 5 kN capacity (EZ-L; Shimadzu Corporation, Kyoto, Japan) that pulls ring-shaped tissue constructs to failure was used to test the tensile strength of the fibroblast tubes. To conduct the test, a construct that was 5-mm long was placed around two parallel stainless steel wire hooks that were 3 mm apart. The hooks were then pulled apart at a rate of 40 mm/min until tissue failure. The force required was measured digitally using a data acquisition system (Trapezium; Shimadzu Corporation). The tests were filmed to verify that construct failure had occurred in the middle of the tissue away from the hooks.