Ultrasonography and MRI are highly reliable and reproducible methods of determining the separation of a ruptured Achilles tendon and the degree of tendon repair in the course of healing. While MRI is expensive, it can be restricted to research and special indications. In a randomized trial a operative treatment and a conservative/functional treatment with a newly developed boot were compared in 50 patients (22 of whom underwent operative treatment and 28, conservative treatment). In this trial there were no significant differences either in the functional results or in the course of healing. Functional treatment in both groups allowed shorter periods of rehabilitation, and acceptance of the boot was particularly high in all patients.