Results of treatment to repair or restore defects like this (called osteochondral lesions) can be measured by comparing MRI images before and after treatment. MRIs are able to show the location and depth of the defect as well as the presence and percentage of regenerated tissue and condition of the cartilage and bone. MRIs also show how well the new cells are integrated into the surrounding cartilage, joint surface, and edge of the lesion.
MRIs can show the percentage of defect filling and how much of the new tissue is actual cartilage versus fibrocartilage. Patients who develop more tissue like hyaline cartilage and less like fibrocartilage have a better chance of good recovery. In a recent study from Italy using stem-cells as a reparative agent, patients who had 80 per cent hyaline cartilage with only 20 per cent fibrocartilage had the best results.
Clinical outcomes are often considered the best measure of results. Using pain, motion, weight-bearing status, ankle alignment, physical activity, and level of sports participation treats the patient not the picture. Follow-up arthroscopic exams (referred to as second-look procedures are more invasive than MRIs and don’t provide complete structural information about the entire repaired area. It might be worth asking your surgeon about the possibility of using imaging over the second-look arthroscopy. There may be reasons why he or she suggested arthroscopy to take into consideration.