congenital deficient meniscus means development of knee arthritis
as the meniscus prevents rubbing of articular or joint surface and deficiency here gradually leads to osteoarthritis
in long run.
You should take glucosamine
tabs 500 mg twice daily for several months to prevent further deterioration and to halt progress of arthritis
As you are having acute pain, you may need ibuprofen
400mg thrice daily after meals for 7 days,give hot fomentation and rub volini gel on the knee,neck