I have a full tear of peroneal longus tendon ( 4cm) will surgery be best or can i get away with therapy rehab and be full function using only brevis? i am a high level athlete , 53 years old ?

As a high level athlete who wants to return to your prior level of activities, I recommend consulting an orthopedic specialist with an interest in sports medicine. You want the best advice, care & rehab that will result in complete healing. You may have to call the department of orthopedic surgery at a university hospital near you to get such a specialist.