Hey there, your doctor may have used quad board just to demonstrate you the correct method... There is absolutely no need to buy a quadriceps board to strengthen your vastus medialis obliqus muscle... however it is important for you to contract and hold the muscle properly, for this you can use a pillow or a rolled towel underneath your knee and can easily continue the exercises with same effect... to get best outcome of VMO rehab, in addition to this exercise, you can start half squats with your back supported against wall, repeat it 10 times, 3 times a day... further, may be after a week when you feel no exertion doing it 10th time, progress it to full squats... feel free to ask anything if in doubt... hope this helps...