Effects of focal muscle vibration on physical functioning in patients with knee osteoarthritis: a randomized controlled trial

BACKGROUND: Knee osteoarthritis (OA) is a chronic condition characterized by pain, stiffness and functional limitations. According to the OsteoArthritis Research Society International (OARSI) recommendations, patients with knee OA should undertake regular quadriceps muscle strengthening exercises. Whole body vibration (WBV) proved its effectiveness in strengthening of the quadriceps muscles and improving balance in chronic knee OA patients. To date, there are no published studies that investigated the effects of focal muscle vibration (FMV) in these patients. AIM: The aim of the present study was to evaluate the effects of FMV on physical functioning in patients with symptomatic knee OA. DESIGN: Randomized controlled trial. SETTING: Outpatient clinic, University Hospital. POPULATION: Men and women aged 60 years or older with radiographic diagnosis of mild to moderate monolateral knee OA (Kellgren-Lawrence grade II or III) and chronic knee pain. METHODS: Patients were randomized in two groups (treatment group and placebo control group). The treatment group received FMV treatment, according to the "repeated muscle vibration" protocol. The control group received a sham treatment. The primary outcome measure was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Secondary outcome measures were the Short Physical Performance Battery (SPPB) and the Performance-Oriented Mobility Assessment (POMA). Follow up evaluations were done at 3 and 6 months. RESULTS: Fifty patients were recruited and randomly assigned to either the study or control group. There was a statistical significant difference between the two groups both for primary (WOMAC) and secondary (SPPB and POMA) outcomes. CONCLUSIONS: In this study, FMV therapy has proven to be effective and safe in improving functioning of patients affected by mild to moderate chronic knee OA. CLINICAL REHABILITATION IMPACT: The use of FMV therapy might be an additional and safe tool in the conservative management of knee OA.