The unhappy triad is usually best treated with surgical intervention - it is not common for an ACL tear to heal on its own, nor is a meniscus tear.
With that said, an orthopedic physician is the best qualified medical professional for intervention.
Numerous therapists can help to work towards recovery for conservative intervention - Physical Therapists, Athletic Trainers, Physiotherapists, etc can all provide valuable rehabilitation which can sometimes allow a person to return to normal daily activities without surgical intervention. But an orthopedist is usually still the best choice to start with.