Clinical outcomes and complications of a collagen meniscus implant: a systematic review

The purpose of this systematic review was to summarise and evaluate the clinical outcomes of the collagen meniscus implant (CMI) and its complication and failure rates. These data were then used to evaluate the results of the CMI at different follow-up time periods and investigate possible differences in the behaviour of lateral and medial CMI. A comprehensive search was performed in PubMed, MEDLINE, CINAHL, Cochrane, EMBASE and Google Scholar databases using various combinations of the following keywords: collagen meniscus implant or collagen meniscal implant. All studies evaluating medial or lateral CMI using the Lysholm score, visual analogue scale (VAS) for pain, Tegner activity scale and subjective or objective International Knee Documentation Committee (IKDC) scores were included in the systematic review. Eleven studies were included in the systematic review. The pooled number of patients involved in CMI surgery were 396 (90.2 % medial, 9.8 % lateral), with a mean age at surgery of 37.8 years. Concomitant procedures were present in 48.8 % of patients; most of them were anterior cruciate ligament (ACL) reconstruction, high tibial osteotomy (HTO) and microfractures. The Lysholm score and VAS for pain showed an improvement at six months up to ten years. No noticeable differences were present comparing short-term values of Lysholm score between medial and lateral CMI. The Tegner activity level reached its peak at 12 months after surgery and showed a progressive decrease through five and ten years post CMI implantation, however always remaining above the pre-operative level. Only a few knees were rated as nearly abnormal or abnormal at IKDC grading at all follow-up evaluations. The CMI could produce good and stable clinical results, particularly regarding knee function and pain, with low rates of complications and reoperations.