What should I expect after osteochondroma surgery in my left inner side of my knee? How long on crutches? Will I need a cast or brace for some time?

Call your doctor. You need to ask this question to your treating doctor. The rehabilitation after surgery for osteochondroma depends highly upon the size of the tumor and the tumor location near your knee. At 28, you have probably had it for some time. The AAOS has great information on osteochondroma to help you learn more. Best of luck to you. http://orthoinfo.aaos.org/topic.cfm?topic=A.