Over 75% of patients who failed prior treatment have improved pain, function after ACI

The study included patients with large femoral defects and modified Cincinnati Scores of 5 points or less.

CALGARY, Alberta — Treating full femoral cartilage defects using autologous chondrocyte implantation may provide significant and lasting improvements in both pain and function in patients with who failed other prior treatments, according to a study presented here.

Brian J. Cole, MD, MBA, and colleagues at several centers in the U.S. and Canada, prospectively evaluated the efficacy of autologous chondrocyte implantation (ACI) in 126 patients who completed 4-year follow-up. These patients averaged 35 years of age, and all had failed previous treatment for femoral articular cartilage defects, including microfracture, osteochondral autograft or debridement, according to the study.

Patients had a mean index lesion size of 4.63 cm² and had a modified Cincinnati pain score of 5 points or less before undergoing ACI, performed using Carticel autologous cultured chondrocytes [Genzyme].

Preoperatively, the modified Cincinnati pain score averaged 2 points, according to the study.

Investigators found that ACI was successful in 76% of patients. Also, at all follow-up evaluations, patients showed significant mean improvements in all outcome measures, including Short Form-36 (SF-36) scores and subscores for the Knee Injury and Osteoarthritis Outcome Score (KOOS).

At 4 years, KOOS scores had improved as follows:

pain: from 48.7 points preop to 72.2 points;
symptoms: from 51.8 points preop to 70.8 points;
sports /recreation: from 25.8 points preop to 55.8 points;
knee quality: from 20.9 points preop to 52.2 points; and
activities of daily living: from 58.6 points preop to 81 points.

Also at 4 years follow-up, the modified Cincinnati score for overall knee condition improved from 3.26 points preoperatively to 6.31, Visual Analog Scale scores improved from 28.8 points to 69.9 points and SF-36 scores for overall physical health improved from 33 points to 44.4 points, according to the study.

"Patients with large, symptomatic cartilage defects after failing previous treatment can expect sustained and clinically meaningful improvement in pain and function following ACI," Cole told Orthopedics Today.

The investigators defined failure as complete graft failure, additional treatment with the cartilage repair procedure or failure of the Cincinnati score to improve over three 6-month intervals. They discovered that 49% of patients underwent subsequent surgical procedures. Of those, 40% had ACI-related procedures mainly for hypertrophy and arthrofibrosis.

Cole said that the procedure can help some of the most challenging patients.

"So it's the fact that you're taking a really challenging group that has failed other treatments, and in fact almost up to two surgeries per patient before they had ACI, and the majority of which were considered to be successful with meaningful clinical improvements [after ACI]," he said.

For more information:
Brian J. Cole, MD, MBA, MBA, director of the Rush Cartilage Restoration Center, Rush University Medical Center, 1725 W. Harrison Street, #1063. Chicago, IL 60612, 312-432-2300, bcole@rushortho.com. He has indicated that he is a Genzyme consultant.
Cole BJ, Brewster R, DeBerardino T, et al. Improvement in symptoms and function after autologous chondrocyte implantation (ACI, Carticel) in patients who failed prior treatment, results of the study of treatment of articular repair (STAR). Presented at the American Orthopaedic Society for Sports Medicine 2007 Annual Meeting. July 12-15, 2007. Calgary, Alberta.