Objective: To investigate the effects of ultrasound (US) in isokinetic muscle strengthening exercises on functional status of patients with knee osteoarthritis (OA).
Design: Effectiveness of isokinetic muscle strengthening exercises for treatment of periarticular soft tissue disorders was compared with and without pulsed and continuous US.
Setting: Outpatient exercise program in a Taiwan medical university hospital.
Participants: One hundred twenty subjects with bilateral knee OA (Altman grade II).
Intervention: Subjects were randomized sequentially into 1 of 4 groups. Group I received isokinetic muscular strengthening exercises, group II received isokinetic exercise and continuous US, group III received isokinetic exercise and pulsed US treatment, and group IV was the control group.
Main outcome measures: Therapeutic effects of isokinetic exercise were evaluated by changes in ambulation speed and the Lequesne index. In addition, changes in knee range of motion (ROM), visual analog scale for pain, and muscle peak torques during knee flexion and extension were compared. Compliance in each group was recorded.
Results: Each treated group had increased muscle peak torques and significantly reduced pain and disability after treatment and at follow-up. However, only patients in groups II and III had significant improvement in ROM and ambulation speed after treatment. Fewer participants in group III discontinued treatment due to knee pain during exercise. Patients in group III also showed the greatest increase in walking speed and decrease in disability after treatment and at follow-up. Gains in muscular strength in 60 degrees /s angular velocity peak torques were also noted in groups II and III. However, group III showed the greatest muscular strength gains with 180 degrees /s angular velocity peak torques after treatment and follow-up.
Conclusions: US treatment could increase the effectiveness of isokinetic exercise for functional improvement of knee OA, and pulsed ultrasound has a greater effect than continuous US.