|
Clinically most of the surgical methods for reconstruction of posterior cruciate ligaments have proved not so successful and have therefore been abandoned. The reconstruction of posterior cruciate ligament using meniscus is technically simple and has theoretical advantage; meniscus is essentially avascular and receives its nourishment from the synovial fluid. But little is known about the fate and the strength of transferred meniscus. The present study was designed to observe the results of replacement ligament plasty of the posterior cruciate ligament with medial meniscus in rabbits. 37 rabbits were used as test animal. In all cases the posterior cruciate ligament of the right knee was removed and replaced by medial meniscus. The rabbits were sacrificed, and gross and microscopic changes of the transferred menisci were studied at one, two, three, four weeks, 3 and 5 months affer operation in 28 rabbits respectively. Measurement of tensile strength of operated and opposite normal knee using modified Clayton et al (1968) method were carried out at 4 weeks in 5 and 5 months in 4 rabbits. Results of the study were presented below. 1. Histologically, at two weeks, fibroblast and vessel from fibro-connective tissue invaded into the intra-articular portion of transferred meniscus. Collagen formation and realignment appeared in the transferred meniscus. At five months, the tranferred meniscus had essentially the appearance of a normal ligament except in some area having remnant of focal fibrocartilage. 2. Histologically, at 3 months, the transferred meniscus was incorporated into the femur much like the normal attachment of the posterior cruciate ligament. 3. The implanted meniscus within the substance of medial femoral condyle was accomplished by infiltration of cells from the surrounding bone marrow into degenerated meniscus, ultimately replaced by new bone. Remodeling of osseous tunnel noticed at 5 months postoperatively. 4. In all cases but one, in tensile strength test, the meniscus ruptured at its tibial attachment and did not pull loose at the femoral attachment, nor did rupture occur in the substance of the meniscus itself. 5. The percentile tensile strength of transferred menscus was averaging 23.35±1.30%, of normal posterior cruciate ligament at five months. As a result of this study, it is evident that transferred menisci rapidly incorporate to bone, become vascularized and histologically change to ligamentous structure, Therefore, the meniscus seems to be a useful substitute as a cruciate ligament.
|