THE MECHANICAL-PROPERTIES OF THE 2 BUNDLES OF THE HUMAN POSTERIOR CRUCIATE LIGAMENT

Successful reconstruction of ligaments requires knowledge of the prope rties of the intact ligament. This study examined the strength of the human posterior cruciate ligament (PCL), treating it as two separate f ibre bundles. It was hypothesized (i) that the mechanical and material properties of the anterolateral (aPC) and the posteromedial (pPC) bun dles of the PCL were significantly different and (ii) that previous st udies have underestimated the strength of the whole PCL. The propertie s of the two bundles were measured in 10 donors (53-98 yr). The mechan ical and material properties of the two bundles were found to be signi ficantly different, the aPC was six times as strong as the pPC. The aP C had a mean strength of 1.6 kN. Allowing for age effects this study s uggests that the strength of the PCL in young active people is 4 kN, w hich is higher than that suggested by previous studies. Because of the difference in the strengths of the two bundles, we conclude that the aPC is primarily responsible for the stabilising effect of the PCL. We therefore recommend that PCL reconstructions should be centered on th e middle of the aPC bundle.