Surgical repair is the most successful form of treatment. Debridement of the tendon, along with the repair, followed by proper recovery, are extremely important for your dog. You will need to go to a specialist for the surgery as it is not a common surgery general veterinarians perform often. Depending on the type of injury to the Achilles tendon, the surgical approach will vary. Once surgery is complete, it is imperative the tarsal is immobilized and supported properly. If not cared for properly, the tendon repair will not hold. Your dog will have some sort of external stabilization, such as a splint, which will keep the tarsus in place and slightly extended but in the weight-bearing position.
In order to monitor the repair of the tendon, your veterinarian may recommend ultrasounds periodically. The full healing process may take years as it is a slow process. Your dog will need extensive physical therapy if you want him to be able to continue to use his foot and leg properly. There are ranges of motion he will need to be put through on a daily basis for him to be able to keep his flexibility in the region as it heals. Not moving it will freeze the area and can lead to permanent disability. Additional physical therapy may be suggested in the form of swimming or a water treadmill to begin with. This will encourage your dog to continue to use the affected region but without the added pressure of all his body weight as the water will be holding him up.
Laser light therapy may also be beneficial to his recovery. Also known as photobiomodulation, the laser light increases blood flow to the area which promotes healing, provides an analgesic effect and can penetrate down to all the tendons affected.