Just happened to see your message and since i just "happened" to look at this Asana (Yoga term for exercise) on YouTube recently, that seems simple to do and I´m sure very helpful - am passing it on! http://www.youtube.com/watch?v=HzQU4lQUnwA
Hoping it will help you get your knee and spine healthy again.
Glad you are also trying castor oil packs.