COLLAGEN MENISCUS IMPLANTS (CMI) DECREASE REOPERATION RATES IN CHRONIC PATIENTS: A SURVIVORSHIP ANALYSIS

Abstract

Introduction: Meniscus loss increases the rate of knee degeneration, leading to additional surgeries or even knee replacement. We determined if replacement of lost meniscus tissue with the Collagen Meniscus Implant (CMI) decreased the need for additional surgeries in multi-operated chronic knees by performing a statistical “survivorship” analysis.

Methods: Patients 18 to 60 years old who had undergone one to three prior partial medial meniscectomies and currently had clinical symptoms of meniscus pathology were prospectively randomized (Level of Evidence I) either to receive the CMI or have an additional partial meniscectomy and serve as controls. Seventy-seven CMIs were implanted, but 5 were removed within 6 months for technical reasons. Those five patients were excluded from this analysis. The remaining 72 CMIs were compared to 66 meniscectomy only controls over 4 years to determine survivorship. “Survivorship” was defined as not having a second surgery on the study knee.

Results: Four CMI (6%) and 12 control patients (18%) required reoperation through 4 years. Survivorship at one year was 89% for control and 97% for CMI patients, 87% for control and 95% for CMI patients at 2 years, 83% and 94% respectively at 3 years, and 79% for control and 94% for CMI patients at 4 years. CMI patients had a significantly higher survivorship than controls (p=0.02). Confidence interval (CI) analysis revealed that meniscectomy only control patients were 3.8 times [CI 95%: 1.2 to 12.4] more likely to require repeat surgery than CMI patients who retained the implant.

Conclusion: In those patients who retained the implant, the CMI decreased the need for additional surgery for chronic knee injuries in multi-operated patients. The additional tissue regeneration supported by the CMI may decrease or minimize progression of degenerative changes and reduce the necessity for additional surgeries.