SURVIVORSHIP OF COLLAGEN MENISCUS IMPLANTS (CMI) COMPARED TO MENISCECTOMY ONLY: A 5-YEAR ANALYSIS IN CHRONIC KNEE PATIENTS

Abstract

Purpose: Meniscus loss leads to decreased clinical function and activity levels and increases rate of knee degeneration, thus leading to additional surgeries or even knee replacement, especially in chronic patients. Chronic patients are more focused on preserving their knees and avoiding additional surgeries. The purpose of this study was to determine if replacement of lost or irreparable meniscus tissue with the Collagen Meniscus Implant (CMI) decreased the need for additional surgeries in multiply operated chronic knee patients compared to meniscectomy only. We hypothesized that patients who gained meniscus tissue with the CMI would require fewer surgeries than meniscectomy only controls through five years.

Methods: In this prospective randomized multicenter clinical trial (Level of Evidence I), patients 18 to 60 years old who had undergone one to three prior partial medial meniscectomies (PMM) and currently had clinical symptoms of meniscus pathology were randomized either to receive the CMI or have an additional PMM (control). Eighty-five CMI were implanted, but one was removed at 3 weeks after an incision wound infection, and two patients died. The remaining 82 CMI patients were compared to 66 controls over 5 years to determine survivorship. Survivorship was defined as not having an additional unplanned surgery outside the experimental protocol on the study knee.

Results: Follow-up rate at 5 years was 96%. Eight CMI patients (9.5%) and 15 control patients (22.7%) required reoperation through 5 years. Survivorship at one year was 90% for control and 95% for CMI patients, 86% for control and 95% for CMI patients at 2 years, 83% and 92% at 3 years, 79% for control patients and 91% for CMI patients at 4 years, and 74% for control patients and 89% for CMI patients at 5 years. CMI patients had a significantly higher survivorship compared to controls (p=0.04). The risk (odds) of reoperation was 2.7 times greater for controls compared to CMI patients at 5 years (95% CI=1.2 to 6.7). Furthermore, the majority of control patient reoperations occurred prior to 24 months, but only four CMI reoperations occurred during the first 24 months.

Conclusion: This study confirms that chronic patients who received the CMI required fewer additional surgeries in their multiply operated knees than PMM only controls through 5 years. The additional tissue regeneration supported by the CMI may decrease progression of degenerative changes and reduce necessity and frequency for additional surgeries. This study further confirms the importance of preserving as much meniscus tissue as possible at time of meniscus surgery, and clearly it supports potential positive benefits of regrowing or regenerating lost meniscus tissue. Our hypothesis was affirmed.