MPFL reconstruction using a quadriceps tendon graft Part 1: Biomechanical properties of quadriceps tendon MPFL reconstruction in comparison to the Intact MPFL. A human cadaveric study

Background: The aim of this study was to analyze the structural properties of the original MPFL and to compare it to a MPFL-reconstruction-technique using a strip of quadriceps tendon. Methods: In 13 human cadaver knees the MPFLs were dissected protecting their insertion at the patellar border. The MPH, was loaded to failure after preconditioning with 10 cycles in a uniaxial testing machine evaluating stiffness, yield load and maximum load to failure. In the second part Quadriceps-MPFL-reconstruction was performed and tested in a uniaxial testing machine. Following preconditioning, the constructs were cyclically loaded 1000 times between 5 and 50 N measuring the maximum elongation. After cyclic testing, the constructs have been loaded to failure measuring stiffness, yield load and maximum load. For statistical analysis a repeated measures (RM) one-way ANOVA for multiple comparisons was used. The significance was set at P < 0.05. Results: During the load to failure tests of the original MPH, the following results were measured: stiffness 29.4 N/mm (+ 9.8), yield load 167.8 N (+ 80) and maximum load to failure 190.7 N (+ 82.8). The results in the QT-technique group were as follows: maximum elongation after 1000 cycles 2.1 mm (+ 0.8), stiffness 33.6 N/mm (+ 6.8), yield load 147.1 N (+ 65.1) and maximum load to failure 205 N (+ 77.8). There were no significant differences in all tested parameters. Conclusions: In a human cadaveric model using a strip of quadriceps-tendon 10 mm wide and 3 mm deep, the biomechanical properties match those of the original MPFL when tested as a reconstruction. (C) 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license