40 acute traumatic ruptures of the Achilles tendon were evaluated in a prospective study after open repair using an early functional rehabilitation protocol. The age of the patients averaged 43 (23-64) years. The operation consisted of a Kessler suture and microadaptation of the tendon. A special boot was used for after treatment. The boot was used 9 (1-18) weeks and full weight bearing was reported after 7 (1-16) weeks. The sick leave time averaged 5.5 (0-18) weeks. After 1 year, length and ankle joint motion were restored. Outcome was assessed using a 100-point score described by Thermann. After 4 months it averaged 73.5 +/- 15.5 points and after 1 year 94.5 +/- 6.0 points. There were no perioperative complications. One rerupture occurred 6 weeks postoperatively and was operated successfully. The combination of surgical repair and early functional after treatment resulted in normal function after 1 year, but requires cooperation of the patient.