I should add,
Low back pain is not , by it's presence , an indicator of the presence of inflammatory events sufficient to give rise to referred pain and altered behavior/sensation distally. The two are not mutally inclusive. In plain speak, you do not need to feel back pain to have evidence of back involvement in a referred event.
Secondly , the levels mobilised do not correspond with your symptoms, so whatever benefit was derived from this attention , presuming you are accurate in your understanding of exactly what levels were mobilised, this would not alter or benefit your sense of posterior knee pain.
Thirdly , x-ray and other highly valued information in the diagnosis of pathology , rarely if ever gives usefull direction in the presence of a hypomobile, irritated, but non "injured "spine. The best evidence is provided by sight and touch, history and experience. Not artifacts and photographs of details not involved in the protective responses active in a sore back.