Synthetic Medial Meniscus Implant Demonstrates High Reoperation Rates: Patients Who Retain Implant or Require Exchange Show Improvement in Post Meniscectomy Pain.

Purpose: To evaluate the clinical outcomes in the use of a synthetic medial meniscus implant in patients symptomatic after medial meniscectomy and not responsive to nonoperative treatment.

Methods: This single-arm, multicenter, prospective study enrolled subjects between ages 30 and 75 with postmeniscectomy pain. Changes from baseline to 24 months were measured in the pain subscale of the knee injury and osteoarthritis outcome score (KOOS) and in KOOS overall (average of all 5 subscales) in patients that had received a medial meniscus implant. Success was a 20-point improvement at 24 months, and reoperation rates and implant failures were recorded. Visual Analog Scale, International Knee Documentation Committee, and Western Ontario Meniscal Evaluation Tool scores were also measured.

Results: Of the 115 treated patients, 3 (2.6%) were either lost to follow-up or missed the 24-month visit, 48 (43%) patients had at least 1 subsequent surgery, and 12 (10.7%) had the implant permanently removed. Of the remaining 100 patients, the mean KOOS pain improved 28.4 points at 24 months (P < .001), and the mean KOOS overall improved 28.3 points (P < .001). Of the subjects, 76% had mean scores for KOOS pain above the minimal clinically important difference threshold, and 72% of subjects met or exceeded this threshold for KOOS overall. There were 29 patients (25.9%) who underwent implant exchange. The 24-month clinical outcomes were similar between subjects who had an implant exchange and patients who did not have any subsequent implant procedure (P < .2).

Conclusions: The synthetic medial meniscus implant shows high reoperation and failure rates. Patients who retained the implant or required implant exchange showed improved pain and function.