Radial versus Focused Extracorporeal Shock Wave in the Treatment of Knee Osteoarthritis : A Randomized Control Trial

Background Knee Osteoarthritis (OA) is the most prevalent of the chronic rheumatic diseases and is a leading cause of pain and disability in most countries worldwide. The treatment methods for knee OA are diverse for patients with mild or moderate osteoarthritis (OA). Biomechanical intervention, physical therapy and exercise, medication, and intra-articular injections (both corticosteroid and hyaluronic acid) are recommended.

Recent studies have suggested that extracorporeal shock wave therapy is an effect treatment method for the knee OA. Based on the propagation pattern of the wave, extracorporeal shock wave therapy can be classified into two main modalities: focused and radial shock wave therapy. However, no previous study compared the effect of radial versus focused type of extracorporeal shock wave on symptoms and functions in patients with symptomatic knee OA. Therefore, the purpose of our study was to compare the effects of focused and radial shock wave therapy on patients with knee OA. Design: Randomized control trial Setting: Outpatient rehabilitation clinic in our hospital. Population:100 patients with mild and moderate knee OA Methods: Patients were randomly assigned to receive three sessions of either focused or radial shock wave therapy at 1-week intervals. The extracorporeal shock wave will be applied to the patellofemoral and tibiofemoral borders and the subchondral bone of the medial tibia condyle of the affected knee joint. The intensities that were used during focused shock wave therapy (0.20 mJ/mm 2 ) and radial shock wave therapy (3 bar) were comparable. The patients were evaluated at baseline and at 1, 4, and 8 weeks and 6 nmonths after the final shockwave treatment. The primary outcome measure was visual analogue scale. The secondary outcome measures were Western Ontario and McMaster Universities Osteoarthritis Index, the knee joint ROM, and sonographic findings and six-minute walk test (6MWT) will be performed. A linear mixed model with repeated measures was used to compare each outcome measure between the two groups.

Inclusion Criteria:

• people aged 45 years or more
• subjects diagnosed with knee OA according to the clinical criteria of the American College of Rheumatology
• subjects diagnosed with grade II or III OA during radiologicalexamination as defined by the radiological classification of Kellgren and Lawrence (K-L) scale for knee OA
• subjects with tenderness in the medial tibial plateau area
• subjects who had pain on one side of the knee.

Exclusion Criteria:

• patients with a history of spinal stenosis, evidence of neurologic disease by history or physical examination, or secondary causes of arthritis (inflammatory or metabolic)
• those who had a surgical intervention or intra-articular injection in the affected knee in the previous 6 months
• any contraindication to extracorporeal shock wave(pregnancy, cancer, coagulation disorders, inflammatory disease, pacemakers, or other electronic implants).