Monkey Shines (1988) is a no-brainer. They actually work in a sex scene with a quadripilegic using a swing, it is insane this movie was made. Plus Stanley Tucci! Check out the IMDB description
A quadriplegic man has a trained monkey help him with his paralysis, until the little monkey begins to develop feelings, and rage, against its new master.
http://www.imdb.com/title/tt0095652/