Placement of a polyurethane implant is not associated with a chondroprotective effect: comparative study with cases of isolated medial meniscectomy with at least five years of follow-up

Introduction Our main objective was to evaluate clinically and radiologically and compare patients who had undergone partial meniscectomy alone, with those who had received a partial meniscectomy in which a polyurethane implant was placed, with a minimum follow-up of 5 years. Methods We performed a prospective cohort study. Patients were randomly distributed into Group A if they only received meniscectomy or Group B if they received meniscectomy plus a meniscal implant (Actifit ® ). We performed preoperative, postoperative, and 5-year-follow-up functional and radiological evaluations (magnetic resonance imaging). Results Twelve patients (40%) were treated with meniscal implants (Group B); 18 (60%) were treated with a conventional meniscectomy (Group A). Tegner, Lysholm and KOOS scores were evaluated prior to surgery and at 5-year follow-up. Only the Lysholm score showed a significant difference between groups, with a score increase between the preoperative evaluation and the 5-year follow-up evaluation ( p = 0.013). Preoperative and postoperative MRIs were both available in 19 cases (63.3%). Long-term follow-up MRIs were performed in 11 cases of group B. No significant differences were found in functional outcomes or MRI findings (WORMS cartilage score increase p = 0.360). Although total reabsorptions of the collagen meniscus implant were not statistically significant in younger patients, a tendency towards a higher reabsorption process was seen in older patients ( p = 0.015). Conclusion The placement of a polyurethane implant after a wide meniscectomy is not accompanied by a chondroprotective effect over time. There is no functional difference between implant placement and isolated meniscectomy. There is a discrepancy between good clinical results and radiologic appearance of these implants and their underlying cartilage. Level of evidence II, therapeutic study.