Collagen scaffolds are a good surgical option for covering large focal osteochondral defects in the knee. In the recent literature there is a wide range of patient profiles and chondral defect treatments (chondral and osteochondral defects, associated procedures, etc.). The aim of the present study was to evaluate clinical and imaging outcomes with collagen scaffolds and to assess any correlation between medium-term clinical outcome and MRI features. The hypothesis was that there is no correlation between clinical outcome and MRI after 2 years postoperatively.

A single-center retrospective observational study included all patients receiving a MaioRegen® scaffold for large painful focal osteochondral defect of the femoral condyle. There were 17 patients, with a mean age of 28±9 years. Defect locations comprised 12 medial femoral condyles, 4 lateral femoral condyles and 1 lateral tibial plateau. Mean defect area was 4.5±1.4cm². All patients were evaluated clinically and on KOOS and objective and subjective IKDC scales, with MRI at last follow-up.

At a mean follow-up of 46±17 months, mean subjective IKDC was 67.8±23; KOOS scores were: symptoms, 78±22; pain, 78±23; function, 85±20; sports, 66±27; and activities of daily living, 59±25. MRI MOCART score revealed incomplete scaffold healing in 21.4% of cases, with variable signal intensity within regenerated tissue. Functional scores did not correlate with reconstruction aspect on MRI.

3D collagen scaffolds yield good medium-term clinical outcomes in large osteochondral defects of the knee. There is, however, a discrepancy between MRI features of the recipient site and objective and subjective clinical scores. These scaffolds may be a good option for treating large focal osteochondral defects in knees of young patients, but MRI does not provide satisfactory medium-term assessment.