Addressing meniscal deficiency part 2: An umbrella review of systematic reviews and meta-analyses on meniscal scaffold-based approaches.

Purpose: Meniscal injuries are common in knee surgery and often require preservation techniques to prevent secondary osteoarthritis. Despite advancements in repair techniques, some patients undergo partial meniscectomy, which can lead to postmeniscectomy syndrome. To address these challenges, meniscal substitution techniques like scaffolds have been developed. However, a comprehensive synthesis of the existing evidence through an umbrella review is lacking. Methods: A comprehensive search was conducted in the MEDLINE, Embase and Scopus databases to identify relevant systematic reviews and meta-analyses. Studies were screened based on predefined inclusion and exclusion criteria. The quality of included studies was assessed using the AMSTAR-2 tool. Results: A total of 17 studies met the inclusion criteria and were included in the review. Most studies focused on the use of collagen-based scaffolds, with fewer studies evaluating synthetic scaffolds. The majority of studies (52.9%) were rated as having 'Critically Low' overall confidence, with only one study (5.9%) rated as 'High' confidence and most studies exhibiting methodological limitations, such as small sample sizes and lack of long-term follow-up. Despite these limitations, the majority of studies reported positive short-term outcomes, including pain relief and functional improvement, following scaffold implantation. However, some studies noted a relatively high failure rate. Radiographically, outcomes also varied, with some studies reporting morphological deterioration of the implant seen on MRI, while others noted possible chondroprotective effects. Conclusions: Meniscal scaffold-based approaches show promise in the management of meniscal deficiency; however, the current evidence is limited by methodological shortcomings. One notable gap in the literature is the lack of clear guidelines for patient selection and surgical technique. Future research should focus on conducting well-designed randomized controlled trials with long-term follow-up to further elucidate the benefits and indications of these techniques in clinical practice. Additionally, efforts should be made to develop consensus guidelines to standardize the use of meniscal scaffolds and improve patient outcomes. Despite limited availability, synthesizing the literature on meniscal scaffold-based approaches is crucial for understanding research, guiding clinical decisions and informing future directions. Level of Evidence: Level IV.