I need some clarification. What do you mean by dislocate? Does your patella (Knee cap) slide from side to side or do the long bones (Tibia & femur) separate?
Is this a result of an acute injury or is this just something that's always been there?
Depending on the severity of the dislocation you may want to stay away from the arts.
However if you do decide to participate, it's not so much the style that is important, it is your instructor that really matters.
It's not no pain no gain...
It's no BRAIN no gain
Something you may want to explore is Muscle Activation Therapy
http://www.muscleactivation.com/main.html
It's great for preventing dislocations!