Preventing anterior cruciate ligament failure during impact compression by restraining anterior tibial translation or axial tibial rotation

Abstract

Anterior cruciate ligament injury is highly prevalent in activities that involve large and rapid landing impact loads. We hypothesize that restraining anterior tibial translation or axial tibial rotation can prevent the anterior cruciate ligament from failing at the range of peak compressive load that can induce ligament failure when both factors are unrestrained. Sixteen porcine knee specimens were mounted onto a material-testing system at 70-deg flexion. Single 10-Hz haversine impact compression was successively repeated with incremental actuator displacement until ligament failure/visible bone fracture was noted. During impact compression, rotational and translational data of the knee joint was obtained using motion-capture system via markers attached to the setup. Specimens were randomly classified into four test groups: Q (unrestrained setup), A (anterior tibial translation restraint), R (axial tibial rotation restraint) and C (combination of both restraints). The same impact protocol was applied to all specimens. Q specimens incurred anterior cruciate ligament failure in the form of femoral avulsion; the peak compressive forces during failure ranged from 1.4-4.0 kN. A, R and C specimens underwent visible bone fracture with ligament intact; the peak compressive force during fracture ranged from 2.2-6.9 kN. The posterior femoral displacement and axial tibial rotation for A and R specimens respectively were substantially lower relative to Q specimens. Both factors were significantly diminished in C specimens but the peak compressive force was larger compared to Q specimens. Significant restraining of these factors was able to prevent anterior cruciate ligament failure in an impact setup that can induce ligament failure with the factors unrestrained.