Biomechanical Consequences of Replacement of the Anterior Cruciate Ligament with a Patellar Ligament Allograft. Part I: Insertion of the Graft and Anterior-Posterior Testing*

摘要: Nineteen fresh-frozen knee specimens from cadavera were tested for anterior-posterior laxity with 200 newtons of force applied to the tibia. A cylindrical cap subchondral bone containing tibial insertion anterior cruciate ligament was isolated a coring cutter and potted in acrylic. thin wire connected undersurface cap, relative displacement between tibia measured an isometer as extended. The load-cell that recorded intact during testing locked neutral, internal rotation, external rotation. then resected, femoral tunnel drilled at site where readings same those obtained ligament. bone-patellar ligament-bone graft used reconstruct ligament, measurements repeated place. pre-tensioned 30 degrees flexion restore normal laxity. Anterior-posterior tests this level pre-tension (laxity-matched pre-tension) well forty-five greater (over-tension). moment required extend before after both levels pre-tension. When positions laxities forces (generated by tibia) significantly less than corresponding values neutral rotation 20, 30, 45 (p ≤ 0.05). Isometer indicated retracted into joint mean standard deviation 3.1 ± 0.8 millimeters extended full extension. For each specimen, trial within 1.5 At laxity-matched (mean, 28.2 16.8 newtons), reconstructed knees 1.0 millimeter means 0 flexion. Over-tensioning decreased 1.2 did not change bring CLINICAL RELEVANCE: performing test flexed 20 degrees, examiner should place position is greatest which all will be resisted It important recognize does behave so-called isometric fashion. Approximately three retraction last extension (as isometer) reasonable order achieve changes length approximate