There aren't many operations outside of cancer surgery that I would suggest be done as a matter of urgency. If you are a young, athletic person or require to pivot on your knee as part of your occupation and have suffered a ACL rupture, I suggest that you ask your GP to refer you to an orthopaedic surgeon or at least get an MRI (gives detailed images of the knee on the inside). The symptoms of an ACL rupture are, "A knee that constantly feels insecure after a twisting injury and functionally gives way when a pivoting force is applied". A pivot force is when the foot is fixed to the ground and the body turns on top of it.
An ACL deficient and functionally unstable knee has a very high chance of tearing a meniscal cartilage, which can lead to arthritis.
Dr Hazratwala has advanced his surgical technique to only use one hamstring tendon (Semitendinosis) to reconstruct the ACL. The traditional technique uses 2 tendon grafts namely Semitendinosis and Gracilis. These grafts were doubled over to create a 4 strand graft, Dr Hazratwala uses the larger of the two grafts and folds them over 4 times to create the same thickness and strength. This leaves the Gracilis tendon to augment the reconstruction with an Antero-lateral Ligament if required.
Please see links to Dr Hazratwala performing his technique.