How can I cure ligament tear of ankle?

Read below. If this is a grade 1 tear, then immobilization is usually enough. If grade 2 depending on it's extent, this may be cured with a cast or possible surgery. If grade 3 tear, it will undoubtedly require surgery.
Grade and timing. If grade one, brief immobilization followed by range of motion, strengthening and balance exercising. Grade 2 is similar but occasionally, need regenerative techniques like platelet rich plasma, mesenchymal stem cells, or controversially prolotherapy. Grade 3 usually need surgery though depending on the anatomy, and chronicity, the regenerative techniques may work.