Synthetic Medial Meniscus Implant Demonstrates High Reoperation Rates: Patients Who Retain Implant or Require Implant Exchange SHow Improvement For Post Meniscectomy Knee Pain Is Associated With Clinical Improvement But High Reoperation Rates At 2-Years Post-Operatively.

Purpose: The purpose of this study was to evaluate the clinical outcomes in the use of a synthetic medial meniscus implant in patients symptomatic after medial meniscectomy and not responsive to other treatment methods. and not responded to non-operative treatment.

Methods: This single-arm, multicenter, prospective study enrolled subjects between ages 30-75 with post-meniscectomy 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 five subscales) in patients that had received a medial meniscus implant. Success was a 20-point improvement at 24-months, reoperation rates, and implant failures were recorded. VAS, IKDC, and WOMET 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 one subsequent surgery, 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 <0.001), and mean KOOS overall improved 28.3 points (P < 0.001). Seventy-six percent of subjects had mean scores for KOOS pain above the minimal clinically important difference (MCID) 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 < 0.2).

Conclusion: The synthetic medial meniscus demonstrates high reoperation and failure rates. Patients who retained the implant or required implant exchange showed significantly improved pain, function, and quality of life at 24-month follow-up in patients symptomatic following partial medial meniscectomy and failed non-operative management. The high reoperation rate is a concern, and further evaluation is needed to determine any contributing factors.