Hello there,,,, what the doctor actually ment was that your ACL which is a ligament has torn and some injury to the meniscus....now both these things are responsible for stability of the knee....dont worry at all as these injuries after surgical repair and extensive physiotherapy can make you the same athlete which u were before....so dont get tensed about it....also the surgery would be an arthroscopic repair so it would give you minimum scars.
Next Steps
meet an orthopaedic surgeon with your MRI report who specialises in Arthroscopic repairs.
Health Tips
After the surgery you need to start ACL rehabilitation protocol from a trained and experienced Sports & musculoskeletal physio...to get back to your playing level.
regards & take care.