Abstract
To evaluate the therapeutic effect of Pulsed Electromagnetic Field (PEMF) in the treatment of meniscal tears in the avascular region.
Seventy-two twelve-week-old male Sprague-Dawley rats with full-thickness longitudinal medial meniscal tears in the avascular region were divided into 3 groups: control group (Gcon), treated with classic signal PEMF (Gclassic), and high slew rate signal PEMF(GHSR). The HSR signal has the same pulse and burst frequencies as the classic signal, but with a higher slew rate. Macroscopic observation and histological analysis of the meniscus and articular cartilage were performed to evaluate the meniscal healing and progressions of osteoarthritis. The synovium was harvested for histological and immunofluorescent analysis to assess the intra-articular inflammation. The meniscal healing, articular cartilage degeneration, and synovitis were quantitatively evaluated according to their respective scoring system.
Dramatic degenerative changes of the meniscus and articular cartilage were noticed during gross observation and histological evaluation in the control group at 8 weeks. However, the menisci in the two treatment groups were restored to normal morphology with a smooth surface and shiny white color. Particularly, the HSR signal remarkably enhanced the fibrochondrogenesis and accelerated the remodeling process of the regenerated tissue. The meniscal healing scores of PEMF treatment groups were significantly higher than those in the control group at 8 weeks. Specifically, the HSR signal showed a significantly higher meniscal repair score than the classic signal at week 8 (P < .01). The degeneration score (Gcon versus Gclassic: P < .0001; Gcon versus GHSR: P < .0001) and synovitis score (Gcon versus Gclassic: P < .0001; Gcon versus GHSR: P = .0002) of the control groups were significantly higher than those in the two treatment groups.
PEMF promoted the healing of meniscal tears in the avascular region and restored the injured meniscus to its structural integrity in a rat model. Compared to the classic signal, the HSR signal showed the increased capability to promote fibrocartilaginous tissue formation and modulate the inflammatory environment and therefore protected the knee joint from post-traumatic osteoarthritis development.
