Clinical Experience With an Aragonite-Based Scaffold Implant for Knee Cartilage Repair: A Multicenter Case Series

Background There is a growing interest in the use of biomaterials to treat chondral and osteochondral knee lesions, given their ability to replicate the biological and functional properties needed for simultaneous cartilage and bone regeneration. A novel aragonite-based, cell-free biomimetic scaffold (CARTIHEAL AGILI-C^TM, Smith + Nephew, UK) was developed for treating chondral and osteochondral defects in traumatic and osteoarthritic joints. A short-term follow-up study was designed to assess the safety and feasibility of this scaffold.  Materials and methods This retrospective review included data from nine centers in the United States (US) between August 22, 2023 and December 30, 2024. Adult patients (≥18 years of age) who received the aragonite-based scaffold as standard of care for the treatment of knee chondral/osteochondral lesions in accordance with the manufacturer's instructions for use were eligible. There were no prespecified exclusion criteria. All patients underwent magnetic resonance imaging (MRI) for radiologic assessment of knee cartilage lesions, which informed the development of presurgical plans. A diagnostic arthroscopy was performed before arthrotomy to confirm the radiographic findings obtained for preoperative planning. The primary endpoint was the incidence of early clinical and radiographic complications occurring within at least 30 days after the operation. Secondary endpoints included an assessment of the accuracy of presurgical planning relative to intraoperative findings, proportion of implants determined to be improperly implanted based on the first postoperative X-rays, change in the numeric pain rating score from baseline, and the proportion of patients cleared for various postoperative activities. Results A total of 33 patients (34 knees; mean age, 47.2 years; 18 (52.9%) male) were included. After a mean postoperative follow-up of 45.7 days (standard deviation, 14.4), one patient (2.9%) experienced a postoperative complication (pain, with no associated infection). Success rate was 96.97% (95% CI, 84.24-99.92). In 27 (79.4%) cases, the presurgical plan based on MRI was modified following arthroscopic visualization of the knee joint surface. Postoperative radiography revealed no complications for the 28 patients with data. Mean postoperative numeric pain rating significantly improved from 6.6 at baseline to 3.9 at follow-up (p<0.05). The majority of patients (n=24; 70.6%) were cleared for partial or full weightbearing by the 30-day postoperative follow-up visit.  Conclusions This case series across multiple centers in the US demonstrates the clinical safety and feasibility of aragonite scaffold implantation. The flexibility of the scaffold in accommodating intraoperative findings and the low rate of early complications are encouraging.