STUDY: ACI versus Microfracture – no difference


A randomized trial from several Norwegian facilities is indicating that the in vitro cultivation of autologous chondrocytes is not an improvement over microfracture. Researchers enrolled 80 patients with a single symptomatic chronic cartilage defect on the femoral condyle without general osteoarthritis (OA).

Gunnar Knutsen, M.D., Ph.D., a co-author on the study, told OTW, “At 15 years follow-up, we found no significant clinical differences between the autologous chondrocyte implantation (ACI) and the microfracture groups. We did find, however, that 57% of the surviving patients in the ACI group and 48% of such patients in the microfracture group had radiographic evidence of early osteoarthritis.

“Orthopedic surgeons from four university clinics in Norway planned the study in 1998. We wanted to compare a new tissue engineering technique: ACI with a low cost arthroscopic technique: microfracture. This study was an important part of my Ph.D. on cartilage repair.

“We are still not able to regenerate hyaline articular cartilage in adults, and the frequency of osteoarthritis following cartilage surgery is problematic in the long run. In vitro cultivating of autologous chondrocytes for implantation is not proven to be better than microfracture. Since we started the trial, newer generations of both techniques have been introduced, however so far none of these newer generations are proven to be superior.

“There is a need for improvements—and hopefully tissue engineering of cartilage will be successful. Low cost marrow stimulation techniques should still be the first line treatment for contained defects if surgery is indicated.

“In many cases conservative options should be offered before surgery. Arthroscopic surgery in general is debated for degenerative joint disease like early OA and meniscus. However, younger patients with symptomatic cartilage lesions or osteochondral lesions including OCD often needs surgery—and arthroscopic low cost surgery should be our first option.”