We report a review of 54 patients with chronic anterior cruciate ligament rupture treated by patellar-quadriceps tendon graft augmented with polypropylene braid (Kennedy-LAD). The femoral placement of the graft was randomised to either a modified over-the-top (OTT) or a tunnel position obtained by an isometric drill guide (ISO). At the two-year follow-up both procedures had resulted in improvement of subjective knee function and activity level. Stereoradiographic measurements showed reduction of anteroposterior laxity to near normal in about one-third of the patients, but muscle strength and objective functional performance showed little or no changes. The OTT group had better subjective knee function. We were unable to confirm the theoretical advantages of the use of the drill guide, partly because it provided a tibial tunnel which was too anterior.

Using roentgen stereophotogrammetry we have recorded the three-dimensional movements of the knee during an anteroposterior laxity test in 36 patients with torn anterior cruciate ligaments and in three cadaver knees. At 30 degrees of knee flexion and before loads were applied the tibia occupied a more laterally rotated position if the anterior cruciate ligament had been injured. When the tibia was pulled anteriorly knees with cruciate deficiency rotated more laterally and were more abducted than normal knees. Posterior traction induced lateral rotation in the injured knee and medial rotation in the intact one. Precise knowledge of the three-dimensional instability of the anterior cruciate deficient knee may be important when the laxity is evaluated only in relation to one of the three cardinal axes.