OAT better than microfracture in younger athletes’ knees

Significantly more OAT-treated patients returned to their preinjury sports activity level.

Osteochondral autologous transplantation repairs articular cartilage knee defects in younger, active patients better than microfracture, a prospective study shows.

Rimatutas Gudas, MD, PhD, and colleagues at Kaunas University Hospital in Kaunas, Lithuania, randomly assigned 60 patients to undergo treatment with one of the two surgical procedures. All patients had either a single symptomatic osteochondritis dissecans (OCD) or a full-thickness cartilage lesion in a stable knee. No knees had generalized chondromalacia or osteoarthritis, and none had lesions larger than 4 cm², according to the study.

After eliminating three patients who did not complete follow-up, the final data analysis included 57 patients — 28 patients treated with osteochondral autologous transplantation (OAT) and 29 patients treated with microfracture. All patients were younger than 40 years, according to the study.

Using the International Cartilage Repair Society (ICRS) grading system, the researchers classified 23 patients (40%) as highly competitive athletes and 34 patients (60%) as well-trained and frequently sporting.

All knees had lesions classified as ICRS grade 3 or grade 4. Thirty-two knees (56%) had post-traumatic symptomatic full-thickness articular cartilage lesions and 25 knees (44%) had OCD defects. The mean preoperative defect size was 2.8 ± 0.65 cm² for OAT-treated patients and was 2.77 ± 0.68 cm² for microfracture-treated patients. Most defects — 84% — were located on the medial femoral condyle, with the remaining defects located on the lateral femoral condyle, according to the study.

At a mean 37 months follow-up, 27 of 28 (96%) OAT-treated patients had good or excellent results compared with 15 of the 29 (52%) microfracture patients (P<.0001). Both groups had significant improvements in Hospital for Special Surgery (HSS) scores. However, OAT-treated patients had significantly better improvements than microfracture patients.

For OAT-treated patients, mean HSS score improved from 77.88 ± 6.23 at preop to 91.08 ± 4.15 at a mean 37.1 months follow-up (P<.0001). For microfracture patients, mean HSS score improved from 77.22 ± 8.12 at preop to 80.6 ± 4.55 (P<.05), according to the study.

Microfracture patients also began showing deterioration at 37.1 months follow-up, the authors noted.

Both groups also had significant improvements in ICRS scores, although OAT-treated patients again had significantly better improvements. Among microfracture patients, mean ICRS score improved from 50.84 ± 4.07 at preop to 75.59 ± 4.64 at 12 months follow-up (P<.05). For OAT-treated patients, mean ICRS score increased from 50.67 ± 4.05 to 85.88 ± 4.69 (P<.001), according to the study.

Additionally, significantly more OAT-treated patients returned to their preinjury level of sports; 26 (93%) OAT-treated patients vs. 15 (52%) microfracture patients returned to sports at an average of 6.5 months postop.

Second-look arthroscopies also identified nine failures in the microfracture group at a mean 8.4 months postop vs. one failure at 3 months in the OAT group. All failed cases were revised using OAT, the authors said.

Radiographic evaluation showed no evidence of arthritic changes in either treatment group, they noted.

For more information:
Gudas R, Kalesinskas RJ, Kimtys V, et al. A prospective randomized clinical study of mosaic osteochondral autologous transplantation versus microfracture for the treatment of osteochondral defects in the knee joint in young athletes. Arthroscopy. 2005;21:1066-1075.