Will I need an arthroscopy if a doctor thinks I have chondromalacia of the knee?

No. Most patients respond well to exercise, bracing and anti-inflammatory medications. Very few eventually need surgery.
No. Chondromalacia means that the articular cartialge has been damaged. Most commonly this is involves the patella and is treated nonsurgically with therapy. Persistent pain may be an indication for surgery. There are many procedures for this, including realignment and/or a cartilage restoration procedure, like debridement, drilling, microfracture, osteochondral transplant, or carticel(r) graft.
Usually not. Chondromalacia patella. This responds well to therapy, activity modification and nsaid's.