Abstract
Abstract
Objectives
Initial performance of sutured quadriceps tendon (QT) ACL graft constructs is not well studied in human tissue and the results of animal tissue testing may not extend to the human model. Two common methods of preserving human tissue are to freeze the specimens immediately after death or embalm with formalin solution. The purpose of this study is to compare elongations and loads in biomechanical testing of fresh-frozen to that of embalmed quadriceps tendon-suture constructs.
Methods
Twenty QT grafts were harvested from human cadaver specimens, 10 fresh-frozen and 10 embalmed. The grafts were prepared with the modified Prusik knot using a No.2 FiberWire (Arthrex, Naples, FL), mounted in a materials testing machine (ElectroPuls E10000, Instron, Norwood, MA) and subjected to tensile loading based on an established protocol. Each tendon was preconditioned with 3 cycles of 0–100N at 1Hz followed by a constant load of 50N for 1 minute and 200 cycles from 50–200N at 1Hz and then loaded to failure at a displacement rate of 20mm/min. Load and displacement data for each tendon-suture construct was recorded.
Results
The average age of fresh-frozen donors was 77.2 ± 11.3 years, and 81.9 ± 8.6 for the embalmed. Fresh-frozen specimens had greater elongation after pre-tensioning than embalmed specimens (7.29 ± 2.05 vs 5.48 ± 0.70 mm, p = 0.02). Fresh-frozen specimens also showed greater elongation after cyclic loading than embalmed specimens (17.51 ± 7.77 vs 10.49 ± 1.94 mm, p = 0.01). Embalmed specimens were stiffer than fresh-frozen specimens (102.87 ± 8.43 vs 84.53 ± 6.72 N/mm, p < 0.001). No differences were found for elongation after preload, peak load, or cross-sectional area.
Conclusions
Embalmed QT tissues were stiffer than those of their fresh-frozen counterparts. As such, embalmed specimens may not elongate to an accurate degree as seen in vivo.
Declaration of Interest
(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
