Knee trauma often causes meniscal injuries. Only 15% of all tears can be repaired. Partial or complete meniscectomy subsequently leads to an increased incidence of chondral damage and onset of early osteoarthritis. In Europe in 1999, 355 000 meniscal injuries were treated, 284 000 of which required partial or complete meniscectomy

As an alternative to allograft, the collagen meniscus implant (CMI®) can be used for reconstruction. A collagen matrix moulded in the form of a meniscus, this is trimmed to defect size and sutured into place arthroscopically. It then serves as a scaffold for cellular invasion. Indications are tears that require partial meniscectomy or an intact remnant stable meniscus. Cruciate ligament injuries, malalignment, osteoarthritis and stage-IV osteochondral defects are the principal contraindications.

Between July 1998 and March 2000, 10 patients received a CMI in our department. Additional pathologies (four anterior cruciate ligament (ACL) injuries, four varus malalignments and five chondral defects) were treated simultaneously. The Lysholm score increased from 70 to 99 in patients treated with an additional high tibial osteotomy (HTO), from 58 to 91 in the group with ACL reconstruction, from 71 to 93 in patients with osteochondral autologous transplantation (OATS). The Lysholm score of the combined group (two patients with HTO and OATS, two with HTO and ACL reconstruction) improved from a preoperative 69 to 99 postoperatively.

CMI, a biocompatible resorbable implant, induces cellular ingrowth and arthroscopic implantation. However, there are still questions to be answered. Few cases have been reported and no long-term studies have yet been published. It is not yet known whether osteochondral defects, unstable joints or malignment are limitations of using the implants.