Background: Collagen meniscal implant (CMI) is a biologic scaffold that can be used to replace meniscus host tissue after partial meniscectomy. The short-term results of this procedure have already been described; however, little is known about risk factors for failure.
Purpose: To determine the factors that predict failure of meniscal scaffold implantation in a large series of patients treated at a single institution and to better define the indications for surgery.
Study design: Case-control study; Level of evidence, 3.
Methods: The analysis included 186 consecutive patients with a minimum 5-year follow-up who underwent CMI scaffold implantation or combined procedures. Patients' characteristics and details of the surgery were obtained via chart review. Patients with a Lysholm score <65 were considered to have experienced clinical failure. Surgical failure was defined as partial or total scaffold removal.
Results: The final analysis included 156 patients (84%) at a mean follow-up of 10.9 ± 4.3 years. The patients' mean age at surgery was 42.0 ± 11.1 years, and the survival rate was 87.8%. Subgroup analysis identified Outerbridge grade 3-4 (Hazard ratio [HR], 3.8; P = .004) and a lateral meniscal implant (HR, 3.2; P = .048) as risk factors for failure. The survival rate was 90.4% for medial implants and 77.4% for lateral implants. An Outerbridge grade 3-4 (HR, 2.8; P < .001) and time from meniscectomy to scaffold >10 years (HR, 2.8; P = .020) were predictive of surgical or clinical failure.
Conclusion: CMI for partial meniscal deficiency provided good long-term results, with 87.8% of the implants still in situ at a mean 10.9 years of follow-up. Outerbridge grade 3-4, lateral meniscal implants, and longer time from the meniscectomy to implantation of the CMI were identified as risk factors for clinical and surgical failure.
Keywords: CMI; collagen meniscal implant; lateral meniscus; long-term follow-up; meniscal allograft transplant; meniscal scaffold.