Meniscal Allograft Shrinkage-MRI Evaluation

Purpose Meniscal allograft transplantation (MAT) has been shown to be an effective treatment option for patients with symptomatic meniscal-deficient knees. Several studies have described shrinkage after transplantation of a meniscal allograft; however, no study has specifically quantified the rate or degree of shrinkage that occurs. The purpose of this study was to determine the frequency and amount of meniscal shrinkage that occurs following transplantation. Methods A prospective study of 25 patients undergoing MAT was performed. Patients underwent MR scans of the meniscal allograft at 1 and 6 months following surgery. Meniscal volume was determined by laser-based noncontacting 3-D coordinate digitizing system (3-DCDS) to acquire the 3-D geometry of the meniscus. The meniscus volume at 1 and 6 months were compared to determine the amount of shrinkage that occurred. Results The average amount of meniscal shrinkage was 7% (range 0 to 22%). Seventeen (68%) of the grafts showed at least 5% shrinkage and 8 (32%) showed 10% or greater. Conclusion Meniscal allograft shrinkage is common following transplantation. The average amount of shrinkage is 7%; however, nearly 32% of the grafts had 10% or more shrinkage.