Mechanical testing of newly developed biomaterial designed for intra-articular reinforcement of partially ruptured cranial cruciate ligament: ex vivo pig model
Abstract
The study deals with mechanical testing of newly developed material polyethylene terephtalate coated with polycaprolactone nanofibers in combination with biodagradable Hexalon ACL/PCL screws as a new possibility of intra-articular reinforcement of partially ruptured cranial cruciate ligament. Four groups of ex vivo models of pig stifle joints were prepared and tested: a model with intact CCL (group 1), a model with partial CCL rupture (group 2), a model with CCL rupture stabilized with 7 mm Mersilene strip (group 3), and a model with CCL rupture stabilized with 5 mm PET/PCL biomaterial strip (group 4).
The models were loaded in the standing angle of 1000 and the maximum load (N) and the shift (mm) were monitored. The mean maximum peak power and the shift were 1266.0 +/- 146.9 N and 13.7 +/- 2.5 mm for group 1, and 1164.7 +/- 228.2 N and 1 6.8 +/- 3.3 mm for group 2, respectively.
In all cases after reaching the maximum load, a tibial fracture occurred but never a CCL rupture. In groups 3 and 4, the initial fixation failure occurred in the mean values of 375.7 +/- 81.5 and 360.4 +/- 52.0 N, respectively, and with a bigger shift of 52.3 +/- 11.9 mm and 39.4 +/- 14.6 mm, respectively, compared to group 1.
A critical point of failure was the anchoring in the bone. It can be concluded that the PET/PCL substitute in the ex vivo model has mechanically comparable properties with the clinically used Mersilene (R), and based on its proven ability to carry stem cells it could be appropriate for partially ruptured CCL protection.