Description
Importance
Cartilage injury represents a major challenge for the orthopedic surgeon. Currently no treatment demonstrates superior results despite numerous attempts to improve existing and develop new methods. The Norwegian Cartilage Project tested some of the most critical unanswered questions in the field of cartilage repair in two randomized controlled trials focusing on autologous chondrocyte implantation vs. debridement for lesions above 2 cm2 and microfracture vs. debridement for smaller lesions.
Methods: Norway has a population of 5.4 million. Five hospitals in Norway, serving a population of 2 million inhabitants, were recruited to take part in the two RCTs. Recruitment was planned for a four-year period with two years follow-up after treatment.
Sample size calculations verified that in the microfracture-study114 patients were required using standard estimates for significance, and in the autologous chondrocyte implantation-study 84 patients were needed.
Results: Even after 7 years of inclusion the sample size needed in the studies was not met and the study board decided to end inclusion in September 2022. In the microfracture study only 57 % of the estimated number was achieved, while for the autologous chondrocyte implantation study only 34 % of the needed number were achieved.
Conclusion: Even in multi-center studies, the numbers required might be difficult to achieve. We propose that pragmatic RCTs embedded in orthopedic registries might be more effective in this setting in order to test important research questions in orthopedic surgery.
Key words: Articular cartilage injury, knee, RCT, Pragmatic RCT
Level of evidence:2b
