Comprehensive Strategies for Preserving Knee Joint Function: Clinical, Biomechanical, and Biological Perspectives

Knee osteoarthritis and joint degeneration pose significant challenges to global health, particularly among younger, active individuals, where the rising incidence of early joint replacement underscores the need for effective joint preservation strategies. This thesis presents a comprehensive, hierarchical approach to knee joint preservation, prioritizing mechanical alignment correction, meniscal restoration, and targeted cartilage repair to delay or prevent osteoarthritis progression and the need for arthroplasty. Through a combination of clinical outcome studies and translational research, this work elucidates the biomechanical and biological underpinnings of knee preservation, offering evidence-based insights to optimize treatment sequencing and personalize interventions.
The foundation of the proposed strategy is the correction of mechanical malalignment, which is critical to redistributing joint forces and protecting cartilage from excessive stress. Clinical evidence from high tibial osteotomy (HTO) studies demonstrates that realigning the limb axis significantly delays osteoarthritis progression, with HTO postponing total knee arthroplasty by 8–10 years in suitable patients. Malalignment, such as varus or valgus deformities, increases compartmental loading, accelerating cartilage wear and meniscal strain. By establishing a neutral mechanical axis, osteotomy creates a biomechanically favorable environment for subsequent interventions, enhancing the durability of meniscal and cartilage repairs.
Following alignment correction, meniscal integrity is addressed as the second pillar of joint preservation. The menisci are essential for load distribution, absorbing over half of the knee’s axial forces. Loss of meniscal tissue, whether through injury or meniscectomy, doubles or quadruples cartilage stress, significantly increasing osteoarthritis risk. This thesis evaluates meniscal repair outcomes in older adults, demonstrating feasibility in selected patients over 60, and analyzes meniscal allograft transplantation (MAT) survivorship, with a mean durability of 7 years when using bone fixation. Additionally, the synergistic effect of MAT with osteochondral grafting is explored, showing improved midterm outcomes when combined with alignment correction. Translational studies further advance meniscal restoration by investigating cellular enhancement of allografts with mesenchymal stromal cells and developing a verteporfin-enhanced repair model to improve healing in avascular zones, highlighting innovative approaches to restore meniscal function.
The final tier focuses on cartilage repair, targeting focal defects after optimizing alignment and meniscal function. Articular cartilage’s limited self-repair capacity necessitates early intervention to prevent lesion progression. This thesis examines fixation of cartilage-only fragments in juvenile knees, long-term outcomes of osteochondritis dissecans (OCD) stabilization across skeletal maturities, and the influence of defect size on repair necessity. Findings emphasize that cartilage repair success hinges on a stable, well-aligned joint with intact menisci. A systematic review of defect size underscores the need for tailored interventions based on lesion characteristics.
Complementary translational research employs a six-degree-of-freedom robotic platform to assess meniscal stress under physiological loading, providing biomechanical insights into joint preservation strategies. By integrating clinical outcomes with mechanistic studies, this thesis establishes a robust framework for knee preservation, demonstrating that a stepwise approach—addressing alignment, meniscal volume, and cartilage integrity—maximizes joint longevity. These findings inform clinical decision-making, advocate for personalized treatment plans, and pave the way for innovative therapies to enhance knee function and quality of life, reducing reliance on early joint replacement.