COMPARATIVE-STUDY OF THE SIZE AND SHAPE OF HUMAN ANTERIOR AND POSTERIOR CRUCIATE LIGAMENTS

As an important step toward determination of the function of cruciate ligaments, the cross-sectional shapes and areas of the anterior crucia te, posterior cruciate, and meniscofemoral ligaments were evaluated in situ within the same knee with use of a laser micrometer system; Meas urements were made in eight human cadaveric knees at five levels along the midsubstance of each ligament, with the knee at 0 degrees, 30 deg rees, 60 degrees, and 90 degrees of flexion. The posterior cruciate li gament was found to be widest in the medial-lateral direction, whereas the anterior cruciate ligament usually was larger in the anterior-pos terior direction. The cross-sectional shapes of the anterior cruciate ligament generally were noted to be more circular along the entire mid substance than were those of the posterior cruciate ligament. In contr ast, the cross-sectional shapes of the posterior cruciate ligament wer e more circular near the tibia, becoming progressively more elongated toward the femur. The meniscofemoral ligaments were more circular than the cruciate ligaments, with an occasional medial-lateral widening si milar to that of the posterior cruciate ligament. The cross-sectional area of both the cruciate ligaments changed along the length of the mi dsubstance, with the anterior cruciate ligament becoming slightly larg er distally and the posterior cruciate ligament enlarging proximally. The angle of flexion of the knee was not found to have a significant e ffect on the cross-sectional areas of the ligaments but was noted to a lter the cross-sectional shapes. Using within-specimen comparisons, th e cross-sectional area of the posterior cruciate ligament was found to be approximately 1.5 times larger than that of the anterior cruciate ligament at the proximal and midsubstance levels but was only 1.2 time s larger at the most distal level. The total cross-sectional area of t he meniscofemoral ligaments was approximately 22% that of the posterio r cruciate ligament.