Early Intervention with Therapeutic Low-Intensity Pulsed Ultrasound in Halting the Progression of Post-traumatic Osteoarthritis in a Rat Model.

Anterior cruciate ligament (ACL) and meniscus injuries are highly correlated with post-traumatic knee osteoarthritis (PTOA). The aim of this study was to examine whether early intervention with low-intensity pulsed ultrasound (LIPUS) at an intensity of 0.1 W/cm2 helps delay PTOA progression. A PTOA model was established by ACL transection and meniscectomy in male Sprague-Dawley rats. LIPUS intervention (1.0 MHz, 0.1 W/cm2) started on the third day after surgery and continued for 4 consecutive wk. Histopathological analyses and immunoassays of collagen type II and matrix metallopeptidase 13 in joints were conducted. Results indicated that compared with the sham treatment, LIPUS significantly reduced Mankin scores, inflammatory cells and matrix metallopeptidase 13 expression and increased collagen type II expression in rats with PTOA (p < 0.05). Early intervention with LIPUS has beneficial effects on delaying cartilage degradation by reducing synovial inflammation and matrix metallopeptidase 13 expression, as well as enhancing collagen type II expression in cartilage.