|Beitragstitel||Biomechanical Comparison of Suture Material (PDS CTX vs MonoMax) for Achilles Tendon Reconstruction (Adelaide Suture- double strand cross locked suture-technique)|
A possible treatment of the Achilles tendon rupture is the surgery, where the tendon is sutured together. Within our project we were testing the tensile strength of different type of sutures of cadaver Achilles tendon specimens.
Ten pairs of fresh frozen Achilles tendons were obtained from human donors aged 41 – 85. The Achilles tendons were frozen at -20°C after dissection to preserve the biomechanical properties of the tissue.
At the test day the tendons were thawed at room temperature and final preparations done.
About 4cm of both ends of the tendon were fixed between two stainless steel clamps with rounded edges, to prevent the tendon from being damaged at the fixation points. The clamps were cooled using liquid CO2, to freeze the tendon to the clamps, giving it more stability and preventing it from slipping out of the clamps during testing.
Before testing, two reflecting markers were fixed to the tendon about 2cm below resp. above the clamps, using cyanoacrylate glue. These four markers were tracked during different loading conditions with six high-speed digital cameras. The displacement of the markers and the force measured by the load cell were recorded synchronously with the motion analysis system.
The native tendon was loaded under tension until failure in a testing machine. The following loading cycles were performed: Preloading with 1 Hz between 100 and 800N over 20 cycles. Loading until failure with 10kN/sec. Suturing of the ruptured tendon with double strand cross locked suture-technique a) B Braun; MonoMax HRT 40s; b) Ethicon; PDS CTX; Size: 1 (PDS)
Preloading with 1 Hz between 50 and 100 N over 20 Cycles Loading until failure with 10kN/sec.
The measured force at the rupture ranges between 2408N and 5972N (Tab. 2). The area of failure varies with in the different tendons.
The maximal forces in the sutured tendons occurring at the rupture were for the BB-suture between 144 N and 232 N (Mean 197 (SD 67) N) and for the PDS-suture between 158 N and 226 N (Mean 194 (SD 70) N).
The test showed that, the rupture occurs not always at the same location and the force is quit varying depending on the type of rupture. A mid tendon rupture was in the range of 5000 to 6000 N, therefore a good fixation in the clamp is very important. Further the load to failure of the sutured tendons is around 200N. Therefore it can be concluded, that the BB Suture and the PDS-Suture have a similar load until failure for the given test setup.