I have leg calve perthes had surgery when I was 10 now in a lot of pain seems hip replacement is option but I'm only 24 what other options are there?

Therapy first. Long term consequence of perthe's disease include hip dysplasia and arthritis of the hip. Due to your age you should start with therapy and activity modification. Depending on the extent of the dysplasia your surgical options include femoral osteotomy, acetabular osteotomy and hip resurfacing or replacement! you should see your orthopaedic surgeon!
Three options. I can think of at least three other options: 1)osteoplasty-removing a prominent bump if present; 2)osteotomy-cutting and realigning the femoral head to take pressure off a worn area; 3)femoral head resurfacing-covering the ball part of the joint with a metal cap if the cartilage is all worn out. Your current anatomy as evaluated by xray +/- MRI would determine the proper procedure to choose.
Probably the best. It is a good option, but not a great one since it lasts for about 20 years and you're so young. Another option is a hip fusion, which sounds extreme, but it can be converted to a total hip at a later time.