60 patients with knee osteoarthritis were randomized to receive 3 weeks of either ultrasound (US) therapy or neuromuscular electrical stimulation (NMES). Outcomes of interest included pain scores at rest and during activity, the 15 meter walk test, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, stiffness and physical function scores, and muscular architecture of the vastus lateralis and rectus femoris muscles (pennation angle, fascicle length, muscle thickness). Follow up was performed upon the completion of the treatment regimen. Results displayed significantly favourable post-treatment VAS pain scores, both at rest and during activity, and significantly favourable WOMAC pain, stiffness and physical function scores in favour of the US group compared to the NMES group. In contrast, fascicle length and muscle thickness in both the left and right vastus lateralis and rectus femoris muscles were significantly in favour of the NMES group compared to the US group. There were no significant improvements or differences in pennation angle between the two groups.