The role of magnetic resonance imaging in efficacy of low-dose extracorporeal shock wave therapy for patients with knee osteoarthritis

Among many diseases of the joints, the most common is osteoarthritis and, in particular, knee osteoarthritis. Current medicine requires new and improved imaging techniques to assess patients with knee osteoarthritis, which enable early diagnosis, improved understanding of the pathophysiology of osteoarthritis, and the efficacy of the ongoing treatment. Scientific data on the use of magnetic resonance imaging (MRI) as an objective method to assess the impact of shock wave therapy (SWT) on the restoration of damaged cartilage and bone marrow in patients with knee osteoarthritis was analyzed. A search for publications in the PEDro and PubMed databases for the period from 2017 to 2022 was performed. The search was done using the following keywords: “osteoarthritis”/“knee osteoarthritis”, “shock wave therapy”, “magnetic resonance imaging”. Five foreign studies were included in the review as a result of the search (no Russian publications were available). Two studies analyzed the effects of SWT on altered cartilage in patients with knee osteoarthritis. Patients who received oral non-steroidal anti-inflammatory drugs were selected as a comparison group. The authors assessed SWT effects on cartilage using quantitative estimates of T2 relaxation time (T2 mapping) and the severity of bone marrow edema on MRI images. At 24 weeks after treatment, differences in relaxation time on T2-weighted MRI images of the patella, acetabulum, and medial and lateral articular surfaces of the femur and tibia showed no statistical significance compared to those before treatment (t= –1.859; P= 0.076). In conclusion, the authors suggested that the resulting effect of SWT in patients with knee osteoarthritis was due to the use of low energy and stated that research will continue using higher SWT parameters. Another study reported that patients with knee osteoarthritis showed a statistically significant reduction in the area of the subchondral bone marrow lesion 6 months after SWT. In addition, the authors found a correlation between the reduction in subchondral bone marrow lesion size and the improvement in pain scores resulting from the SWT treatment. In another study, MRI scans in patients with knee osteoarthritis documented a positive SWT effect by reducing bone marrow edema. After one year of follow-up, MRI images showed complete regression of bone marrow edema among patients who received SWT. The number of studies that investigated SWT effects on cartilage and bone marrow restoration in patients with knee osteoarthritis using MRI is limited, indicating the need for continued research in this area.