Extracorporeal Shockwave Therapy Accelerates the Healing of a Meniscal Tear in the Avascular Region in a Rat Model

Abstract

Background: The treatment of meniscal tears in the avascular region remains a clinical challenge. Extracorporeal shockwave therapy (ESWT) is a minimally invasive, safe, and effective therapy for various orthopaedic disorders. However, the therapeutic effect of ESWT on meniscal tears has not been reported. Purpose: To evaluate the therapeutic effect of ESWT in the treatment of meniscal tears. Study Design: Controlled laboratory study. Methods: Twelve-week-old male Wistar rats were divided into 3 groups (normal, ESWT–, and ESWT+). The authors made a full-thickness 2-mm longitudinal tear in the avascular region of the anterior horn in the latter 2 groups. At 1 week after surgery, the ESWT+ group received 800 impulses of shockwave at 0.22-mJ/mm2 energy flux density in a single session. The authors performed a histological examination to evaluate meniscal healing (n = 10 for each group) and immunohistochemistry to analyze the expression of bromodeoxyuridine (BrdU; n = 5 for each group) and CCN family member 2/connective tissue growth factor (CCN2/CTGF; n = 5 for each group) at 2, 4, and 8 weeks after ESWT. The mRNA levels of CCN2, SOX 9, VEGF-a, aggrecan, Col1a2, and Col2a1 at the site of the meniscal tear at 4 weeks after ESWT were quantitatively evaluated by a real-time polymerase chain reaction (n = 5 for each group). Results: The meniscus healing scores in the ESWT+ group were significantly higher than those in the ESWT– group at 4 weeks and 8 weeks. The ratio of BrdU-positive cells was the highest in the ESWT+ group at all observation periods. The ratio of CCN2-positive cells was highest in the ESWT+ group at 4 and 8 weeks. In the ESWT+ group, real-time polymerase chain reaction revealed that the levels of CCN2, SOX9, aggrecan, and Col2a1 were upregulated (All significant data were P < .05). Conclusion: ESWT promoted the healing of meniscal tears in the avascular area. ESWT stimulated proliferation of meniscal cells and the upregulation of cartilage-repairing factors such as CCN2, with the upregulation of cartilage-specific extracellular matrix expression. Clinical Relevance: ESWT may be an effective therapeutic option that promotes meniscal healing in the avascular region.

Biophysical Stimulation in Athletes’ Joint Degeneration: A Narrative Review

“…ESWT improved the healing of avascular tears by promoting meniscal cell proliferation and the upregulation of cartilage-repairing factors, such as CCN2, SOX9, aggrecan, and Col2a1, resulting in enhanced synthesis of a cartilage-specific extracellular matrix [68].…”

Extracorporeal shockwave treatment in knee osteoarthritis: therapeutic effects and possible mechanism

“…Additionally, Hashimoto et al [ 56 ] suggested that ESWT could accelerate the healing of meniscal tears in avascular regions that might contribute to OA progression in a rat model. Specifically, ESWT promoted the healing of avascular tears by stimulating the proliferation of meniscal cells and the up-regulation of cartilage-repairing factors, including CCN2, SOX9, aggrecan and Col2a1, leading to the increased production of cartilage-specific extracellular matrix.…”

Extracorporeal shock wave promotes activation of anterior cruciate ligament remnant cells and their paracrine regulation of bone marrow stromal cells’ proliferation, migration, collagen synthesis, and differentiation

“… 23 , 24 ESW treatment potentiates soft tissue regeneration. 25 - 27 Studies have shown that ESW treatment activates proliferation, migration, and gene expression in different cells. 28 - 31 ESW has been proposed as a non-invasive treatment that potentiates graft healing after ACL reconstruction surgery.…”