Safety and Survival Rate of a Biomimetic Osteochondral Scaffold for the Treatment of Lesions of the Knee Articular Surface.

Background: A cell-free biomimetic osteochondral scaffold has been developed to treat lesions of articular knee surface, with good outcomes documented up to long-term follow-up. However, systematic tracking of failures and adverse events (AEs) that might affect the outcome is still missing. Purpose: To analyze the incidence of AEs and failures at long-term follow-up in a large series of patients after knee cell-free scaffold implantation. Study Design: Case series; Level of evidence, 4. Methods: The database with the regulatory-required safety data collected by the manufacturer was utilized. A total of 704 patients with a mean follow-up of 44.8 months (range, 6-180) were included. Data from implantation centers were analyzed focusing on AEs and failures. AEs were divided by the surgeons into surgery related, treatment related, or not related to surgery or treatment, and into serious or mild AEs. Additionally, factors associated with AEs and failures were examined. Results: A total of 177 postoperative AEs were reported in 170 patients (24.1%). Among these, surgeons considered 104 AEs surgery related and 73 treatment related. Moreover, for 45 patients (6.4%), 52 AEs not related to surgery or treatment were reported, which were excluded from the analysis. Mild AEs were reported in 93 patients (13.2%), including minor AEs in the early or postoperative period (such as persistent postoperative symptoms, such as fever, pain, knee swelling, or difficulty of movement) in 82 patients (11.6%). Serious AEs were reported in 66 patients (9.4%), including early or persistent postoperative symptoms in 54 patients (7.7%), joint inflammation in 6 (0.9%), arthrofibrosis in 3 (0.4%), and 0.4% in others. Finally, this scaffold presented a survival rate of 93.1%, according to life table method, (31 surgical failures) at up to 180 months' observation. Demographic and clinical patient characteristics did not significantly influence the risk of postoperative AEs or failures. Conclusion: The implantation of this scaffold for the treatment of knee articular surface lesions presents a high survival rate of 93.1% at long-term follow-up. Mild AEs (13.2%) and serious AEs (9.4%) reported by the treating surgeons in the database consisted mainly of pain and postoperative symptoms. These results can help surgeons to improve the clinical decision-making process and the patient counseling regarding expectations related to the implantation of an osteochondral scaffold to treat articular knee surface lesions.