The Dose-Related Effects of Extracorporeal Shock Wave Therapy for Knee Osteoarthritis

OBJECTIVE: To investigate the dose-related effects of extracorporeal shock wave therapy (ESWT) for knee osteoarthritis. METHODS: Seventy-five subjects were recruited, 60 of which met the inclusion criteria. The patients were randomly classified into two groups: group L, which was a low-energy group (n=30; 1,000 shocks/session; energy flux density [EFD], 0.040 mJ/mm(2)) and group M, which was a medium-energy group (n=30; 1,000 shocks/session; EFD, 0.093 mJ/mm(2)). For each group, 1,000 shock waves were delivered to the medial tibial plateau area, once a week, for 3 weeks. The main outcome measures were the visual analogue scale (VAS), the Roles and Maudsley (RM) score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and the Lequesne index. Each assessment was performed at the baseline and at 1, 4, and 12 weeks after ESWT. RESULTS: In both groups, the VAS, the RM and WOMAC scores, and the Lequesne index were significantly improved over time (p<0.001), and group M showed greater improvement over group L at the 1, 4 and 12 weeks assessments. CONCLUSION: In this study, medium-energy group (group M) showed greater improvement in regard to relieving pain and restoring functional outcome than the low-energy group (group L). Therefore, EFD can be considered to have significant influence when treating with ESWT for knee osteoarthritis.