THE EFFECT OF ANTERIOR CRUCIATE LIGAMENT RESECTION AND IMMEDIATE OR DELAYED IMPLANTATION OF A MENISCUS PROSTHESIS ON KNEE-JOINT BIOMECHANICS AND CARTILAGE - AN EXPERIMENTAL-STUDY IN RABBITS

In a rabbit experiment with anterior cruciate ligament (ACL) resection , immediate substitution of the medial meniscus with a prosthesis was compared with delayed prosthetic implantation after a postmeniscectomy period of three weeks. The knees with a prosthetic implant were compa red with their contralateral joints as well as to joints with an intac t ACL and menisci. Anterior cruciate ligament resection alone led to d isturbed biomechanics and cartilage degeneration. Anterior cruciate li gament resection in combination with meniscus resection increased cart ilage degeneration and led to more inferior biomechanics. Ingrowth and stable fixation was less frequent when the prosthesis was inserted th ree weeks after meniscus resection than when inserted immediately. Fur thermore, in knees with delayed prosthetic implantation, only minor im provement in terms of cartilage protection was shown when compared wit h knees with resection only. In contrast, knees with immediate meniscu s replacement demonstrated similar joint stiffness and stress relaxati on characteristics and similar cartilage protection effects as knees w ith a nonresected medial meniscus.