Treatment of Knee Osteochondritis Dissecans With a Cell-Free Biomimetic Osteochondral Scaffold Clinical and Imaging Evaluation at 2-Year Follow-up

Background: Osteochondritis dissecans (OCD) is an acquired lesion of the subchondral bone that may result in separation and instability of the overlying articular cartilage. Unstable lesions must be treated surgically to reestablish the joint surface as anatomically as possible. Hypothesis/Purpose: The aim of this study was to evaluate the potential of a biomimetic osteochondral scaffold to treat OCD by analyzing the results obtained at 2-year follow-up. The hypothesis was that this scaffold, which was developed to treat the entire osteochondral unit, might restore the articular surface and improve symptoms and function in patients affected by knee OCD. Study Design: Case series; Level of evidence, 4. Methods: Twenty-seven consecutive patients (19 men, 8 women; age [mean SD], 25.5 7.7 years) who were affected by symptomatic knee OCD of the femoral condyles (average defect size 3.4 +/- 2.2 cm(2)), grade 3 or 4 on the International Cartilage Repair Society (ICRS) scale, were enrolled and treated with the implantation of a 3-layer collagen-hydroxyapatite scaffold. Patients were prospectively evaluated by subjective and objective International Knee Documentation Committee (IKDC) and Tegner scores preoperatively and at 1- and 2-year follow-up. An MRI was also performed at the 2 follow-up times. Results: A statistically significant improvement in all clinical scores was obtained at 1 year, and a further improvement was found the following year. At the 2-year follow-up, the IKDC subjective score had increased from 48.4 +/- 17.8 preoperatively to 82.3 +/- 12.2, the IKDC objective evaluation from 40% to 85% of normal knees, and the Tegner score from 2.4 +/- 1.7 to 4.5 +/- 1.6. The MRI evaluations showed good defect filling and implant integration but also inhomogeneous regenerated tissue and subchondral bone changes in most patients at both follow-up times. No correlation between the MOCART (magnetic resonance observation of cartilage repair tissue) score and clinical outcome was found. Conclusion: This biomimetic osteochondral scaffold seems to be a valid treatment option for knee OCD, showing a good clinical outcome at 2-year follow-up. Moreover, the improvement was not correlated with lesion size, so large lesions can benefit from this implant. Less favorable findings were obtained with MRI evaluation.