The role of PCL reconstruction in knees with combined PCL and posterolateral corner deficiency

Although many PCL injuries are in combination with posterolateral corner (PLC) injuries, there has been little work done on combined injury reconstruction; the literature includes differing recommendations. It was hypothesised that a double-bundle PCL reconstruction would restore both posterior drawer and external rotation laxities closer to normal than an isolated single-bundle reconstruction in combined PCL plus PLC-deficient knees. However, it was also hypothesised that an isolated PCL reconstruction would still leave abnormal rotation laxity. In this controlled laboratory study, cadaver knee kinematics were measured electromagnetically with posterior drawer, external rotation, varus rotation loads applied, at sequential stages: intact; PCL-deficient; PCL plus PLC-deficient; double-bundle PCL reconstruction; single-bundle PCL reconstruction. The grafts were tensed using a posterior drawer laxity matching protocol. There was no significant difference between single- and double-bundle PCL reconstructions at any angle of flexion: both reconstructions restored posterior drawer to normal; neither reconstruction restored external rotation or varus laxity to normal. We concluded that, in combined PCL plus PLC deficiency, isolated PCL reconstruction only controls tibial posterior drawer, but is not sufficient to restore rotational laxity to normal. Double-bundle PCL reconstruction was not better than single-bundle, so the added complexity of double-bundle reconstruction does not seem to be justified by these results.