Imbalance in quadriceps muscle activation may give rise to anterior knee pain. 24 patients suffering from this aetiology of anterior knee pain were randomized to determine the effect of a botulinum toxin type A (BoNT-A) injection on pain management of this condition and improving quadriceps muscle balance. Results after 12 weeks indicated that BoNT-A-injected patients experienced more significant reductions in anterior knee-specific pain and functional knee pain, and had a better balance between the vastus lateralis and vastus medialis portions of the quadriceps muscle.