Tissue Gain after Arthroscopic Placement of a Collagen Meniscus Implant (CMI) Following Partial Medial Meniscectomy (SS-36)

Abstract

We determined the amount of new tissue growth in patients in a trial of Collagen Meniscus Implants (CMI) after arthroscopic placement of CMI compared to partial meniscectomy alone. Patients 18-60 years with 1-3 prior partial medial meniscectomies and continued symptoms of meniscus pathology randomly received CMI or additional partial meniscectomy (control). Sixty-three consecutive patients (36 CMI and 27 controls) met all inclusion criteria and had minimum 1-year follow-up. At index surgery, meniscus defect size was measured using special instruments, and percent meniscus loss calculated. All 36 CMI patients underwent relook arthroscopy at 1 year; control patients did not. At relook, the same instrumentation was used to measure amount of meniscus defect filled with new tissue as a result of CMI. Percent meniscus gain was calculated by multiplying % meniscus loss by % defect filled, then dividing that product by the difference of 100% less % meniscus loss. CMI patients lost 66% of their meniscus; control patients lost 62% (p=0.40). We assumed control patients regained no new tissue based on historical controls. At 1-year relook, CMI patients had 63% of their original defect filled by new tissue compared to none assumed in controls. Based on the above formula, CMI patients averaged 200% gain in meniscus tissue compared to controls (p=0.000). CMI supports generation of new tissue that fills meniscus defects. Increased percent of meniscus gain and total amount of meniscus tissue in CMI patients after 1 year is statistically significant compared to partial meniscectomy.