Introduction and purpose: To present the clinical, radiological and MRI results of a series of collagen meniscus implants (CMI) with 4–7 years follow-up.

Materials and methods: We implanted 25 CMI from 1997 to 2000 in 20 men and 5 women between the ages of 18 and 48. Five cases were operated on for postmeniscectomy syndrome, 19 for degenerative ruptures and one for acute rupture. We reconstructed the ACL at the same time in 17 cases (68%).

Results: The Lysholm score went from a preoperative mean of 59.9±15.8 to 89.6±6.3 at 2 years (p< 0.003), while the visual analogue pain score went from a preoperative mean of 7.0±1.8 to 2.0±1.6 (p< 0.001).

Conventional radiology showed no deterioration of the joint line. With MRI we saw a certain degree of meniscal regeneration in 68% of the cases. However, the implant tended to become smaller and it was common to see extrusion in frontal sections.

Three cases had persistent pain on the medial side of the knee. In one we removed the CMI and performed an allogeneic meniscus transplantation (AMT). The second case was treated by valgus osteotomy of the tibia and then AMT in the stage. The last case was not treated.

Conclusions: After 4 to 7 years of BMI follow-up, we found no adverse effects for the knee. Clinically the outcome was good in most of the cases (22/25). Regeneration appeared to occur in over one-third of the cases, although the size was smaller than expected.