Hmm, never heard of that one Darren. I didn't know there were tendons in the quads, but then I'm an accountant, so what do I know?
If the manipulation worked and the therapist "aligned" your pelvis, it may be that you have an imbalance causing your discomfort and that further similar treatment could be the only route to go. Are there any chiropractors/osteopaths in your area who you could see, if your other guy is too busy. It may well be worth travelling a bit to get the right treatment.