Abstract:

Looking at the drawings in Hey Groves' pioneering (1920) description of cruciate ligament reconstruction, it is obvious that what the author had in mind was insertion of the anterior cruciate ligament (ACL) at the anatomical attachment sites, even though he did not make that point in so many words. Palmer was the first to stress the importance of precise drill-hole placement in 1938,and to design his own drill guide to obtain this precision. And only in the last 10years have the biomechanical principles of accurate cruciate reconstruction been established. The term "isometry" was coined to express the need for a near-constant distance between the femoral and tibial attachments of the substitute ligament throughout the range of knee movement. In practice, however, ideal isometry is impossible to achieve, and length variations of up to 2mm are often acceptable. Both the anterior and the posterior cruciate ligament are made up of several bundles, with each bundle consisting of a large number of fibrils. There is no point in the range of movement, including full extension, at which all the ACL fibers would be taut; throughout the range, some fibers will be tense, while others will be slack. The greater part of the stress is taken by the anteromedial bundle; these are the fibers that are tense in full extension. This is why Friederich. et al. recommend ACL reconstruction with drill holes within the proximal and distal attachments of the native anteromedial bundle. Hefzy, et al. tried to determine the factors that affect the region of most isometric femoral attachments of the ACL. They noted that there is no completely isometric attachment. Kentsch and Muller described for the first time a technique for replacing both the anteromedial and the posterolateral bundle using a split patellar tendon graft. One strip would be positioned over the top, the other through a transcondylar tunnel. However, this technique is very difficult and time-consuming.

Authors:

Hans H. Paessler, M.D., ATOS-Klinik, Heidelberg, Germany

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