This retrospective case series reports 2- to 9-year clinical, arthroscopic, and histologic outcomes in 94 evaluable patients from the first 101 treated with autologous chondrocyte transplantation (ACT) for large full-thickness chondral defects (1.5-12.0 cm²) of the knee. Patients were divided into five groups by defect location and diagnosis, and assessed with validated scoring systems, arthroscopic grading, and biopsy histology.
When Brittberg et al. Published the original 23-patient ACT pilot in 1994, it was proof of concept — promising but limited. This Peterson 2000 paper is the first substantial long-term series showing ACT holds up at up to 9 years across a diverse patient population, cementing it as a legitimate treatment for large chondral defects that had failed conventional marrow stimulation.
The clearest clinical decision rule from this paper: location dictates prognosis. Isolated femoral condyle defects are your best candidates (92% good/excellent). Patellar lesions are a different operation. Without concurrent realignment correction, expect only 29% success. Every patellar ACT patient needs a patellofemoral alignment assessment before surgery.
Treat early. Patients treated within 1 year of injury had significantly better Wallgren-Tegner functional scores than those treated later (p < 0.01). Don't let these patients cycle through failed marrow stimulation procedures indefinitely before referring for ACT consideration.
The learning curve is real: 4 failures in the first 23 patients versus 3 in the next 78. Surgeon experience and technical refinement drive outcomes. Context worth knowing when evaluating institutional ACT programs or interpreting early series data.
This retrospective case series reports 2- to 9-year clinical, arthroscopic, and histologic outcomes in 94 evaluable patients from the first 101 treated with autologous chondrocyte transplantation (ACT) for large full-thickness chondral defects (1.5-12.0 cm²) of the knee. Patients were divided into five groups by defect location and diagnosis, and assessed with validated scoring systems, arthroscopic grading, and biopsy histology.
When Brittberg et al. Published the original 23-patient ACT pilot in 1994, it was proof of concept — promising but limited. This Peterson 2000 paper is the first substantial long-term series showing ACT holds up at up to 9 years across a diverse patient population, cementing it as a legitimate treatment for large chondral defects that had failed conventional marrow stimulation.
The clearest clinical decision rule from this paper: location dictates prognosis. Isolated femoral condyle defects are your best candidates (92% good/excellent). Patellar lesions are a different operation. Without concurrent realignment correction, expect only 29% success. Every patellar ACT patient needs a patellofemoral alignment assessment before surgery.
Treat early. Patients treated within 1 year of injury had significantly better Wallgren-Tegner functional scores than those treated later (p < 0.01). Don't let these patients cycle through failed marrow stimulation procedures indefinitely before referring for ACT consideration.
The learning curve is real: 4 failures in the first 23 patients versus 3 in the next 78. Surgeon experience and technical refinement drive outcomes. Context worth knowing when evaluating institutional ACT programs or interpreting early series data.