Focused Extracorporeal Shockwave Therapy for Knee Arthritis

Background: Subchondral bone marrow lesions (BMLs) in knee osteoarthritis (OA) are strongly associated with presence and severity of knee pain, structural deterioration, disease progression with an increased risk of total knee arthroplasty. OA-related BMLs may regress or resolve within 30 months which could be associated with long lasting disability. It has been reported that BMLs persist in the majority of people with knee OA. Different treatment strategies have been proposed including rest and protected weight-bearing, bisphosphonates, subchondroplasty and intraosseous orthobiologic injection. However, conservative treatment response takes a long time and other interventions may be considered invasive procedures that show varying results with several side effects. Focused extracorporeal shockwave therapy (f-ESWT) has been established as a safe non-invasive treatment with positive results in different bone disorders that share the same pathological features of BMLs. Objective: This is an exploratory pilot study to determine the efficacy and safety of f-ESWT for the treatment of BMLs in people with knee OA. Participants: Fifteen subjects with knee OA who have history of knee pain at rest and during walking with the confirmed diagnosis of subchondral BML(s) on magnetic resonance imaging (MRI) despite at least 4 weeks of conservative treatment will be enrolled into this study. Procedures: Subjects will receive a total of 4 focused ESWT sessions (at high energy level) over 4 consecutive weeks. Outcome Measures: Participants will be evaluated for adverse events and changes in pain intensity and knee function, using an 11-point numerical rating scale (NRS; 0-10, with anchors "no pain" and "pain as bad as you can imagine") and; the Knee injury and Osteoarthritis Outcome Score (KOOS; five subscales: pain, other symptoms, function in activities of daily living, function in sports and recreation, and knee-related quality of life), respectively. Subjects will be assessed with these outcome measures at baseline, 1 month, 2 months, 3 months, and 6 months after the treatment. MRI of the involved knee will be performed prior to treatment (baseline) and 3 months and 6 months after treatment. Anticipated Outcomes: Focused extracorporeal shockwave therapy is a safe alternative to treating BMLs and will significantly decrease knee pain intensity and improve function in people with knee OA- related BMLs.