In six intact cadaver knees, we measured how the distance between six selected points in and around the femoral and tibial attachment area of the posterior cruciate ligament (PCL) changed with knee flexion. After complete removal of the PCL, 2-mm drill holes were made at the selected points. Each femoral point was measured against each tibial point using a heavy string that was passed through the drill holes. The distal end of the string was attached to a measuring unit. The changes in femorotibial distance were noted during flexion from 0 degrees to 110 degrees in 10 degree steps. The tibial drill hole locations had only a minor effect on the changes in femorotibial distance. The most isometric point was located in the centre of the posterior intercondylar area. The femoral locations of the drill holes were the primary determinant of whether the distance increased, decreased or remained nearly constant. According to our results, the most isometric femoral point is located at the posterosuperior margin of the anatomical PCL attachment. Using the tibial isometric point as a reference, the femoral points positioned anterior or posterior to the isometric point produced considerable changes in the femorotibial distance upon knee flexion. The anterior point led to an increase of about 7-8 mm at 110 degrees of flexion, the posterior point to a decrease of the same extent. Much smaller changes in femorotibial distance resulted from the points located superior or inferior to the femoral isometric point.(ABSTRACT TRUNCATED AT 250 WORDS)

Isometric positioning of the posterior cruciate ligament (PCL) graft is important for successful reconstruction of the PCL-deficient knee. This study documents the relationship between graft placement and changes in intra-articular graft length during a passive range of motion of the knee. In eight cadaveric knees the PCL was identified and cut. The specimens were mounted in a stabilising rig. PCL reconstruction was performed using a 9-mm-thick synthetic cord passed through tunnels 10 mm in diameter. Three different femoral graft placement sites were evaluated: (1) in four specimens the tunnel was located around the femoral isometric point, (2) in two specimens the tunnel was positioned over the guide wire 5 mm anterior to the femoral isometric point, (3) in two specimens the tunnel was positioned over the guide wire 5 mm posterior to the isometric femoral point. In all knees only one tibial tunnel was created around the isometric tibial point. The location of the isometric points is described in part I of this study. The proximal end of the cord was fixed to the lateral aspect of the femur. Distally, the cord was attached to a measuring unit. The knees were flexed from 0 degrees to 110 degrees, and the changes in the graft distance between the femoral attachment sites were measured in 10 degrees steps. Over the entire range of motion measured, the femoral tunnels positioned around the isometric point produced femorotibial distance changes of within 2 mm. The anteriorly and posteriorly placed tunnels produced considerable changes in femorotibial distance with knee flexion, e.g. about 8 mm at 110 degrees of flexion.

Since August 1989 we have treated acute anteromedial instabilities with medial instability of 1+ and 2+ by augmented anterior cruciate ligament (ACL) reconstruction alone. Subsequently, functional therapy for the lesion of the medial collateral ligament (MCL) was carried out. In a follow-up examination, we evaluated Lysholm, Marshall, OAK and IKDC scores, measured stability with the KT 1000, and tested isokinetic muscle function in 28 patients. The majority demonstrated stable healing of the MCL and ACL and good or excellent knee functions and muscle strength.

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