i will agree with physiobob about the lumbar spine involvement....Consider how easily the lumbar spine can refer pain on to the knee joint...I think that in every peripheral joint problem we must ALWAYS exclude any spinal component, for example in a Wikipedia reference-linkfrozen shoulder u should always screen FIRST the cervical spine...the same rule apply on the knee and a possible spine relationship.....Of course it is obvious as u describe the case that there is a dysfunction on patella, but we cannot exclude the lumbar spine...my opinion is to try in the beginning some repeated movements (ala McKenzie) and then proceed to mobilisation techniques on the lumbar and see the symptomatic response

Take care