This study is testing a new way to help people with knee problems. Some people have injuries called "chondral lesions" in their knee. These are like damage to the cushiony cartilage that helps our knees move smoothly. The study compares two treatments: one is called microfracture, and the other adds a special covering called Chondro-Gide® ACC to help heal large lesions. The study will check if this new method is just as good as treating small lesions with microfracture alone. Participants will need to report how they feel and if they have any problems during the study.

• The study will take place in multiple locations and is double-blind, meaning neither the patient nor the person checking results will know which treatment was given.
• Participants must be between 18 and 55 years old and have a specific type of knee problem.
• Participants cannot have certain conditions, like another knee problem, some types of arthritis, or be pregnant.

If you're interested, you should be ready for check-ups and follow a plan to help your knee get better.