Emerging Therapies Using Bioactive Scaffolds for Meniscus and Cartilage Interface Repair

Abstract

The meniscus and cartilage interface plays a critical role in knee joint function, and injuries to this region are prevalent among both athletic and general populations. Historically, repair and regeneration of the meniscus-cartilage interface have posed significant clinical challenges due to the avascular nature and complex biomechanical environment of these tissues. Recent advances in tissue engineering have introduced bioactive scaffolds as promising therapeutic modalities to enhance repair and functional restoration. This review synthesizes current evidence on the epidemiology, pathophysiology, risk factors, clinical features, diagnosis, and management of meniscus-cartilage interface injuries, with a focused discourse on emerging therapies utilizing bioactive scaffold technologies. Emphasis is placed on mechanism-based approaches, clinical outcomes, and future directions, providing physicians with an up-to-date resource for evidence-based decision-making.

Introduction

Meniscal and articular cartilage injuries are among the most common intra-articular knee pathologies encountered in orthopedic practice. The interface between meniscus and cartilage is uniquely predisposed to degenerative and traumatic lesions, with significant implications for joint biomechanics, load transmission, and long-term osteoarthritis risk. Despite advances in arthroscopic techniques, conventional repair strategies are often limited by poor intrinsic healing capacity, especially in avascular regions. Bioactive scaffolds, engineered to provide both structural support and biological cues for tissue regeneration, have emerged as a promising frontier in the management of these complex injuries. This article delivers a comprehensive analysis of the clinical problem, elucidates underlying mechanisms, and explores current and emerging scaffold-based therapies to inform optimal patient care.

Epidemiology / Disease Burden

Meniscal tears are reported in up to 60% of patients undergoing knee arthroscopy, with a peak incidence in young athletes and older adults with degenerative changes. Cartilage lesions, frequently coexisting with meniscal pathology, are identified in approximately 36% of knee arthroscopies. The disease burden is compounded by the high prevalence of knee injuries, leading to pain, functional limitation, and progression to osteoarthritis. The societal and economic impacts are substantial, driving the need for effective and durable repair strategies.

Pathophysiology

The meniscus-cartilage interface is characterized by a transition from fibrocartilaginous to hyaline cartilage, facilitating smooth load transfer and joint stability. The region's avascularity, low cellularity, and unique extracellular matrix composition impede intrinsic healing following injury. Disruption of this interface leads to altered joint mechanics, increased contact stress, and progressive chondral degeneration. Understanding these pathophysiological mechanisms is essential for designing effective biomimetic repair solutions.

Risk Factors

Major risk factors for meniscus and cartilage interface injuries include acute trauma (sports injuries, falls), chronic repetitive loading (occupational activities), age-related degenerative changes, obesity, limb malalignment, and previous knee surgery. Genetic predispositions and systemic metabolic factors may further modulate tissue resilience and repair capacity, highlighting the multifactorial nature of these injuries.

Clinical Features

Patients typically present with joint line pain, swelling, mechanical symptoms (locking, catching), and reduced range of motion. Chronic injuries may manifest as persistent discomfort, instability, and functional decline. A thorough clinical assessment, including history, physical examination, and functional evaluation, is vital for identifying the extent and impact of meniscus-cartilage interface lesions.

Diagnosis

Diagnosis relies on a combination of clinical suspicion and imaging modalities. Magnetic resonance imaging (MRI) remains the gold standard for non-invasive visualization of meniscal and chondral pathology, enabling detailed assessment of lesion size, location, and interface involvement. Arthroscopy provides direct visualization and is considered the reference standard for definitive diagnosis and intraoperative management planning.

Treatment & Management

Conservative management, including rest, physiotherapy, and pharmacologic interventions, may be appropriate for stable, non-displaced tears or low-demand patients. Surgical approaches, such as meniscectomy, meniscal repair, and microfracture, are indicated for symptomatic, function-limiting lesions. However, standard techniques are limited by incomplete healing, risk of re-injury, and progression to osteoarthritis, particularly at the meniscus-cartilage interface. As such, there is growing interest in regenerative strategies that address both biomechanical and biological deficits.

Recent Advances / Emerging Therapies

Bioactive scaffolds represent a paradigm shift in the management of meniscus and cartilage interface injuries. These constructs, often composed of natural or synthetic polymers, are engineered to mimic native extracellular matrix and incorporate bioactive molecules (e.g., growth factors, cytokines) to enhance cell recruitment, proliferation, and matrix synthesis. Recent preclinical and early-phase clinical studies have demonstrated improved integration, tissue regeneration, and biomechanical properties using scaffold-based approaches. Techniques under investigation include cell-seeded scaffolds (e.g., mesenchymal stem cells, chondrocytes), composite scaffolds combining meniscal and chondral components, and smart scaffolds with controlled release of bioactive agents. Notable products in clinical use or trials include collagen-based scaffolds, polyglycolic acid (PGA) constructs, and hyaluronic acid hydrogels. These innovations offer the potential for restoring native tissue architecture and function, reducing the risk of osteoarthritis, and improving long-term clinical outcomes.

Guideline Recommendations

Current clinical guidelines emphasize the importance of preserving meniscal and cartilage tissue whenever possible and recommend repair over resection, particularly in young and active patients. The use of bioactive scaffolds is increasingly supported as an adjunct to conventional repair techniques in cases with poor healing potential or complex interface injuries. Selection of scaffold type, cell source, and augmentation strategy should be individualized based on patient factors, lesion characteristics, and available evidence. Ongoing research and clinical trials will continue to inform best practices and refine guideline recommendations.

Conclusion

The repair of meniscus and cartilage interface injuries remains a formidable clinical challenge due to the region's limited regenerative capacity and complex biomechanical environment. Bioactive scaffolds have emerged as a promising solution, offering both structural support and biological stimulation to facilitate tissue regeneration. While preliminary outcomes are encouraging, further research is required to optimize scaffold design, delivery, and integration with host tissue. Multidisciplinary collaboration between clinicians, scientists, and engineers will be essential for translating these advances into routine clinical practice, ultimately improving patient outcomes and quality of life.