Matrix-Augmented Bone Marrow Stimulation With a Polyglycolic Acid Membrane With Hyaluronan vs Microfracture in Local Cartilage Defects of the Femoral Condyles: A Multicenter Randomized Controlled Trial

Background: Microfracture (MF) is an established operative treatment for small, localized chondral defects of the knee joint. There is evidence from animal studies that matrix augmentation of bone marrow stimulation (m-BMS) can improve the quality of the repair tissue formation.

Purpose: To evaluate the therapeutic outcome of a matrix made of polyglycolic acid and hyaluronan as compared with a conventional MF technique.

Study design: Randomized controlled trial; Level of evidence, 1.

Methods: Patients between the ages of 18 and 68 years who had an articular femoral cartilage defect of 0.5 to 3 cm² in the weightbearing area of the femoral condyles with indication for MF were included in this study. Patients were randomized and treated with either MF or m-BMS with Chondrotissue. Defect filling, as assessed on magnetic resonance imaging (MRI), at postoperative 12 weeks was defined as the primary outcome measure, with follow-up MRI at weeks 54 and 108. Follow-up data were also collected at 12, 54, and 108 weeks after surgery and included patient-reported clinical scores: visual analog scale for pain, Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score, and 36-Item Short Form Health Survey.

Results: MRI scans confirmed cartilage repair tissue formation in both groups 12 weeks after treatment. There was no significant difference between the m-BMS and MF groups in the percentage of defect filling at 12, 54, and 108 weeks postoperatively. No significant difference was found in terms of patient-reported clinical scores. Both groups showed significant improvement in 4 KOOS subscales-Pain, Activities of Daily Living, Sport and Recreation, and Quality of Life-at 54 and 108 weeks after treatment.

Conclusion: This is the first randomized controlled trial comparing m-BMS with a polyglycolic acid matrix with hyaluronan with MF. The use of the Chondrotissue implant in m-BMS has been proven to be a safe procedure. No difference was found between m-BMS and MF in terms of patient-reported outcome scores and MRI assessment until postoperative 2 years. Long-term follow-up studies including histological assessment are desirable for further investigation.

Registration: EUCTR2011-003594-28-DE (EU Clinical Trials Register).