Chondral defects of the knee are common and often seen in young and active individuals. A novel single stage arthroscopic technique for the treatment of articular cartilage defects in the knee is described. This involves microfracture and application of concentrated bone marrow aspirate cells (BMAC) with fibrin and Hyaluronic Acid as a gel. After a representative preclinical study, the 5 year results of a prospective clinical study are presented.

The pre-clinical study involved two groups of rabbits with standardised lesions treated with microfracture alone and microfracture combined with fibrin/HA/BMAC application. New cartilage from both groups was subjected to staining with H&E for tissue morphology, toluidine blue (collagen) and safranin O (GAG), immunohistochemistry with antibodies for collagen type I and II, and scanning and transmission electron microscopy to analyse the microstructural morphologies. The fibrin/HA/BMAC group scored better than the microfracture group on all tests.

A subsequent prospective clinical study patients (n=60) with symptomatic ICRS grade III/IV chondral defects (lesion size 2–8cm2). The surgical procedure involved debridement of the lesion, micro-fracture and application of fibrin/HA/BMAC gel under CO2 insufflation. Patients underwent morphological evaluation with MRI (T2*-mapping and d-GEMRIC scans). Clinical assessment employed the Lysholm, IKDC and KOOS scores while radiological assessment was performed with MOCART score.

At 5 years, Lysholm score was 78, compared to 51 pre-operatively (p<0.05). KOOS (symptomatic) improved to 90 from 66 (p<0.05). IKDC (subjective) went to 80 from 39 (p<0.05). The mean T2* relaxation-times for the repair tissue and native cartilage were 26 and 29.9 respectively. Average MOCART score for all lesions was 70.

This technique shows encouraging clinical results at 5 year follow-up. The morphological MRI shows good cartilage defect filling and the biochemical MRI suggests hyaline like repair tissue.