Long-term clinical and MRI outcomes of a polyurethane meniscal scaffold implantation for the treatment of partial meniscal deficiency: A minimum 10-year follow-up study.

Purpose: To assess the clinical and magnetic resonance imaging (MRI) results after implantation of a polyurethane scaffold for chronic segmental meniscus deficiency following partial meniscectomy in a long-term follow-up.

Study design: Level IV, retrospective case series.

Methods: Thirty-two knees received arthroscopic implantation of an Actifit® polyurethane meniscal implant for deficiency of the meniscus. Clinical outcomes were assessed using patient-reported outcome scores, including Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm, Tegner Activity Scale and visual analogue scale (VAS) for pain and satisfaction. Preoperative MRI scans and final follow-up radiographs and MRI evaluations were performed to assess scaffold morphology, tissue integration and the status of the articular cartilage.

Results: The mean follow-up was 11.4 years. Significant improvements were observed in clinical outcomes, with KOOS improving from a preoperative mean of 47.75 (standard deviation [SD]: 16.88) to a 78.62 (SD: 15.45), Lysholm scores from 46.62 (SD: 16.96) to 84.62 (SD: 13.03), Tegner Activity Scale improving from 1.8 to 4.1 at the final follow-up. The VAS for pain decreased from a preoperative mean of 5.62 (SD: 2.54) to 2.12 (SD: 2.02). MRI evaluations using the Genovese classification showed 23 knees with Type II scaffolds, 0 with Type III and 9 with Type I. Bone oedema was not present in 27 knees, with 5 knees showing Type I bone oedema. Meniscal extrusion was observed in 24 knees with partial extrusion and 8 knees with complete extrusion. The contralateral meniscus was normal in 28 knees and graded as Reicher Grade 1 in 2 knees. The Kellgren-Lawrence classification revealed 15 knees with Type I osteoarthritic changes, 10 with Type II changes and 7 with Type III changes.

Conclusion: Arthroscopic treatment for patients with chronic segmental meniscal loss using a polyurethane meniscal implant can achieve sustainable long-term results regarding pain reduction and knee function. However, the MRI did not reveal normal menisci in all cases.

Level of evidence: Level IV.