Cell-Free Biomimetic Osteochondral Scaffold for the Treatment of Knee Lesions: Clinical and Imaging Results at 10-Year Follow-up

Background: Cell-free devices have been introduced to restore osteochondral defects, avoiding the limitations of cell-based procedures. Among these, an osteochondral scaffold made of type I collagen and hydroxyapatite has been investigated with promising results up to medium-term follow-up. However, the clinical and imaging results over time still need to be documented. Purpose: To evaluate the clinical outcome and tissue maturation at long-term follow-up after the implantation of the osteochondral scaffold. Study Design: Case series; Level of evidence, 4. Methods: A total of 24 patients (7 women, 17 men; age, 36 +/- 9.5 years) underwent surgical implantation of the osteochondral scaffold and were prospectively evaluated before surgery, at 2-, 5-, and 10-year follow-up. The mean defect size was 2.9 +/- 1.4 cm(2). Patients were evaluated using the International Knee Documentation Committee (IKDC) subjective and objective scores, and the activity level was documented with the Tegner score. Magnetic resonance imaging (MRI) evaluation involved the use of the magnetic resonance observation of cartilage repair tissue score combined with 5 more variables focused on the bone layer. Results: A statistically significant improvement of all clinical scores was documented from the baseline to the final evaluation. The IKDC subjective score improved from the preoperative level to 2 years (41 +/- 13.2 and 77.1 +/- 14.6, respectively) (P<.0005), with stable results up to 10 years (77.4 +/- 19.4). The IKDC objective score changed from 52% of normal and nearly normal knees before the treatment to 84% at 10 years (P<.0005). Tegner sports activity at the final evaluation (3.8 +/- 1.7) was higher compared with the preoperative level (1.6 +/- 1.1; P<.05), but it remained significantly lower compared with the preinjury level (5.5 +/- 2.6; P<.05). Treatment failed in 1 patient. Persisting graft alterations were observed on MRI scans, although without correlating with the clinical outcome. Conclusion: The regenerative potential of this scaffold is limited, as demonstrated by the signal alterations persisting over time on MRI scans. On the other hand, the clinical improvement was significant and stable over time both in terms of subjective and objective outcomes, including activity level, with overall good results.