Association between meniscal extrusion and disease severity in knee osteoarthritis: a retrospective case-control study

Objective To explore the relationship between meniscus compression and the severity of knee osteoarthritis. Materials and methods A retrospective case-control study included 95 patients with knee osteoarthritis (OA) admitted to our hospital from April 2021 to July 2023, who were grouped into slight protrusion of meniscus group (n = 48) and severe protrusion of meniscus group (n = 47) according to the degree of meniscal extrusion. Various parameters, including Kellgren/Lawrence classification, imaging findings, cartilage damage grading, physical function assessments, and correlation analyses, were used to evaluate the relationship between meniscal extrusion and disease progression. Results The study revealed significant associations between severe meniscal extrusion and measures of disease severity, including reduced cartilage thickness(3.24 +/- 0.61 versus 3.78 +/- 1.45; P = 0.019), increased meniscus degeneration grade (2.86 +/- 0.54 versus 2.23 +/- 1.63; P = 0.013), diminished joint space width (4.56 +/- 0.73 versus 4.86 +/- 0.52; P = 0.025), elevated meniscal extrusion(3.68 +/- 1.78 versus 2.85 +/- 1.54; P = 0.018), greater bone marrow lesion volume(6.13 +/- 1.85 versus 5.21 +/- 1.58; P = 0.011), advanced cartilage damage(t = 0.016), and impaired physical functioning. Correlation analyses indicated a positive relationship between meniscal extrusion and disease severity(r > 0). While the predictive value of meniscal extrusion alone was modest (AUC = 0.617), a combined model integrating various parameters yielded a high predictive value for disease progression (AUC = 0.853). Conclusion Meniscal extrusion was associated with disease severity and functional decline in knee osteoarthritis patients and has potential predictive value for disease progression.