Clinical Outcomes of Meniscal Replacement for Meniscus Deficiency: A Systematic Review of Current Evidence.

Abstract

<h4>Background</h4>Meniscal replacement aims to restore function and delay joint degeneration in patients with symptomatic meniscus deficiency; nonetheless, comparative evidence among different implant options-meniscal allograft transplantation (MAT), collagen meniscus implant (CMI), and polyurethane scaffolds-remains limited.<h4>Purpose</h4>To systematically review and compare the clinical outcomes of MAT, CMI, and Actifit (polyurethane scaffold).<h4>Study design</h4>Systematic review; Level of evidence, 4.<h4>Methods</h4>Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a standardized search and review strategy was employed to identify clinical evidence of any designation examining clinical outcomes and implant-associated adverse events after meniscal replacement with specified implants. Effect sizes were calculated via standardized mean deviations and illustrated through forest plots to compare against the minimal clinically important difference (MCID) for relevant patient-reported outcome measures. The primary outcomes were clinically significant improvements in functional status and pain relief. Secondary outcomes included failure rates, reoperations, and other reported adverse events, as well as indirect evidence of chondroprotection.<h4>Results</h4>A total of 50 studies were included. All 3 implant types yielded statistically significant functional improvements (all reported <i>P</i> < .05), with scores such as the International Knee Documentation Committee and the Lysholm often exceeding the MCID. However, pain relief was inconsistent and frequently failed to achieve the MCID. Failure rates differed markedly among implants, with the mean failure rate being lowest for CMI (5.2%), highest for Actifit (15.9%), and intermediate for MAT (11.4%). Radiological evidence indicated a potential chondroprotective effect; nevertheless, it was not conclusive.<h4>Conclusion</h4>Meniscal replacement effectively improves patient function, but pain relief is unreliable, and failure risks vary by implant type. The current evidence is insufficient to definitively recommend one implant over another. Clinical decisions must be individualized, considering patient-specific factors, concomitant pathologies, and the unique risk profile of each implant. High-quality, head-to-head randomized controlled trials are urgently needed.