PubMed · 8998876
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
C D Harner. 1996. Editorial comment.. https://doi.org/10.1097/00003086-199604000-00001
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Eight normal cadaveric knee specimens were used to evaluate the effects of femoral and tibial tunnel positions on length excursions of a single wire and bone-patellar tendon-bone graft as measured by an isometer. Femoral attachment sites were varied by using a commercially available femoral pin guide with either a 5.5- or 7.0-mm offset and by aiming with the guide oriented vertically (12:00 notch position) or rotating 45 degrees toward the lateral condyle (1:30 or 10:30 notch position depending on right or left knee). Tibial isometry was altered by testing the wire against the posterior tunnel wall or 5-mm anterior using a custom centering device. Isometry was measured from 0 degrees to 120 degrees for each position tested. A 7-mm offset guide rotated to the 12:00 position yielded the best single fiber and graft excursion patterns (P < .05). A 5.5-mm offset guide yielded inferior single fiber and graft excursion patterns. Single fiber and graft isometry were found to be similar, but not identical in endoscopic anterior cruciate ligament reconstruction. Centering the single fiber in the tibial tunnel had little effect on excursion patterns, showing that the more posterior tibial positions needed for endoscopic reconstruction are acceptable from an isometry standpoint.
Graft failure in anterior cruciate ligament (ACL) reconstruction can result from anterior placement of the tibial tunnel. Conventional radiographic evaluation of this problem does not take into account potential changes in tibio-femoral relationship caused by ACL instability. A retrospective radiographic evaluation of failed as well as successful ACL reconstructions was carried out. Both published radiographs as well as those obtained of patients treated by the authors were evaluated for tibial tunnel placement, roof impingement, and tibial position relative to the femur. In the second part of the study, the radiographs were obtained under standard conditions in both failed ACL reconstructions and normal knees. The results of both parts of the study indicate that lateral radiographs of the extended knee with ACL instability are likely to show subtle anterior tibial subluxation. The subluxation can give the impression of roof impingement on the graft. However, the majority of the failed knees had similar tibial tunnel placement compared with successful reconstructions and would appear unimpinged once corrected for subluxation. The diagnosis of graft impingement by the femoral intercondylar roof has to take into account potential tibial subluxation. Impingement as a cause graft failure may be less common than previously thought.
A problem that is frequently encountered during endoscopic anterior cruciate ligament reconstruction bone-patellar tendon-bone autograft is that the graft is often too long and protrudes from the tibial tunnel. If less than 20 mm of the bone plug remains in the tibial tunnel, interference screw fixation cannot safely be used, and an alternate form of fixation may have to be employed. A simple technique has been developed to deal with this problem. The technique involves bone-grafting the tibial tunnel with a cancellous core of bone that is removed while creating the tibial tunnel. This not only makes it possible to safely use interference screw fixation in all cases, but it also makes it possible to place the point of graft fixation very near the anatomic anterior cruciate ligament insertion site.