Biomechanical investigation of posterolateral structures and reconstruction procedures of the knee joint

Background: Patients with isolated posterior cruciate ligament deficiencies frequently do not have major symptoms of knee instability. If the posterior cruciate ligament disruption is associated with other deficiencies, severe instability can occur, whereas posterolateral rotary instability is one of the most common. In such case, reconstruction of the posterior cruciate ligament alone doesn`t give satisfying results, and an additional reconstruction of the posterolateral structures has to be done. Numerous techniques for reconstruction of the posterolateral structures have been published, but several clinical results have been discussed controversially. In the present study, a biomechanical analysis of different methods of reconstruction of the posterolateral instability is performed, to find, which of the techniques is the most anatomical form of reconstruction. Methods: In this study, cadaver knees are used. At first skin and muscles will be removed. Then CT-scans of all specimens are made, to preparate them for the biomechanical investigetions using a 3D-Knee analyzer. The 3D- Analyzer, developed especially for this purpose, is able to simulate each point of the object and all movements in several axes of space on the computer. At first the range of motion (flexion-extension, internal-external rotation) is measured, followed by testing the passive joint-stability (AP-Laxity) Several measurements are performed at the following conditions: 1. Intact knee joint, 2. Transection of the posterior cruciate ligament, 3. Transection of the posterolateral structures, 4. Reconstruction of the posterior cruciate ligament alone, 5. Reconstruction of the posterolateral structures, using different surgical techniques.