Patients with a ruptured Achilles tendon are often surprised to hear that they do not require an operation to repair it. Natural healing is, in fact, extremely reliable. Treatment in a boot with “functional rehabilitation” gives excellent results. Surgical treatment is not required except in certain circumstances. Surgery always carries more risks than non-surgical treatment.
This scientific paper from the UK was published in 2015. It remains the best evidence for how an Achilles tendon rupture should be treated.