As mesenchymal stem cells have the capacity to differentiate into a variety of cells, many have explored the use of those cells for the treatment of chondral defects. This study used such cells to develop a three-dimensional, tissue-engineered construct (TEC), containing undifferentiated, synovial-derived mesenchymal cells, surrounded by extracellular matrices synthesized by the cells.

Subjects were five patients, 20 to 60 years of age with isolated, full-thickness cartilage defects of the knee. After an arthroscopic biopsy, a volume of TEC was created, and later implanted onto the defect site. Partial weight bearing was allowed at six weeks, and full weight bearing at eight weeks. Assessments occurred on the date of surgery, on postoperative day one, and then at weeks one, two, four, six, 12, 24 and 48. The participants were followed with MRI for up to two years postoperatively. The primary outcome was the safety of the procedure.

No serious adverse events were noted within the first two years. At two years, the defect filling rate reached 100% coverage, with good integration to adjacent cartilage in all cases. All outcomes scores, including pain and function scores, were significantly improved and remained high at 24 weeks.

This study of adults with knee chondral defects found that, by using a new, scaffold-free, tissue-engineered mesenchymal stem cell repair, patients could have complete defect repair combined with significant improvement in function and symptoms.