No abstract

In arthroscopically assisted anterior cruciate ligament reconstruction using hamstring tendon graft, the graft rotates slightly as the femoral screw is inserted. Its final position tends to be in the anterior half of the tunnel in right knees, resulting in clinical laxity. To perform identical procedures on left and right knees, a reverse-thread screw was designed for femoral fixation in right knees. We prospectively studied 80 patients undergoing right-knee anterior cruciate ligament reconstruction with hamstring tendon autograft. Thirty-six patients underwent reconstruction with a standard screw and 44 underwent reconstruction with a reverse-thread screw. The same technique, performed by the same surgeon, was used on all patients. At 12 months' follow-up, the average side-to-side differences on arthrometry testing were 2.00 mm for the standard screw group and 0.95 mm for the reverse-thread screw group using a manual maximum test, and 1.66 mm and 1.00 mm, respectively, using the 20-pound test. Both differences were statistically significant. Of the standard group, 23% had a manual maximum difference of 3 mm or more, compared with 8% of the reverse-thread group. A significant difference was found between these two groups for Lachman test (77% with grade 0 for the standard group compared with 92% for the reverse group) but pivot shift and Lysholm knee score were not significantly different. The use of a reverse-thread screw for femoral fixation in right-knee anterior cruciate ligament reconstructions in men significantly decreased laxity at 12 months after surgery compared with standard screw fixation.

The maximum flexor and extensor peak torques about the knee joint of 17 male and 17 female subjects were determined using a CYBEX isokinetic dynamometer. These values were used to evaluate the influence of changing joint angular-velocity on the ratio of peak hamstrings torque to peak quadriceps torque. Additionally, an assessment of the influence of gravity on the recorded peak torques, and thus the ratio, was made Values for the flexion-extension ratio corrected for gravity were found not significantly different at the measured joint angular-velocities whereas the values of the ratio not corrected for gravity were found significantly different at increasing joint angular-velocities It is necessary that the physiotherapist recognize the importance of the influence of gravity when recording forces developed in the vertical plane.