Abstract—The load dynamic of multi-strand flexor tendon repair is still unclear as a high friction of suture at the locking loops. The purpose of this study is to find out the equivalent forces acting on the multi-strand flexor tendon repairs by using free body diagram analysis. Forty porcine flexor tendons were harvested and transversely cut from the middle of tendons to facilitate tendon repairs. 6-strand Lim- Tsai repair, consisting of 2 Lim-Tsai loops, and 4-strand Cruciate repair, with 3 cross-stitch loops, were adopted to repair the 40 tendons equally. Ultimate tensile strength was recorded. The repair strength of 6-strand Lim-Tsai repairs (90.8±11.3N) had no statistically difference as compared to 4-strand Cruciate repairs (89±10N) despite of having different number of strands. This is because only the 2 strands connected to the end knot was in “Tension” mode due to natural pulling of strands while tying the knot. The other strands were only tensioned after the 2 strands ruptured. This “step down” phenomenon could be caused by the uneven load bearing associated with the Lim-Tsai repair configuration. This method could be very useful to analyse the loading mechanism of different flexor tendon repairs which leads to the development of new repair techniques.

Cite: Yoke-Rung Wong, Mun-Kitt Austin Loke, Ita Suzana Bte MAT JAIS, Chuan Shing Lee, and Shian Chao Tay, "Free Body Diagram Analysis for Investigation of Flexor Tendon Repair" International Journal of Pharma Medicine and Biological Sciences, Vol. 4, No. 3, pp. 180-183, July 2015. doi: 10.18178/ijpmbs.4.3.180-183