What is an Achilles Tendinopathy?
The canine achilles tendon is comprised of 5 different muscles, whose tendons come together at the calcaneus of the tarsus (ankle). These muscles are the gastrocnemius, superficial digital flexor, biceps femoris, gracilus, and semitendinosis. Damage can occur to any or all of these tendons. Injuries to the achilles tendon can be chronic or acute and can have varying degrees of severity.
In chronic tears, there is small damage that occurs without sufficient healing leading to more damage. This is referred to as achillodynia. Achillodynia can eventually lead to a complete rupture. In acute injuries we see a disruption of the tendon that ranges from mild to a complete rupture. A history of trauma may be present such as a jumping down, lunging, or laceration.
Clinical signs include acute lameness, possible plantigrade stance, thickening or swelling in the achilles tendon, possible rolling in of the toes due to shortening/ increased tension on the superficial digital flexors. An open wound may or may not be present.
Diagnosis is based on our physical exam paired with a musculoskeletal ultrasound. One can also pursue advance imaging such as MRI or CT.
Severity of Injury
We like to grade the severity of the injury to help guide us toward the optimal treatment plan. We use a combination of our exam findings and diagnostics to grade the severity of injury.
- Type I. The pet may present with a plantigrade stance due to complete disruption of the tendon. This presents as the ankle is dropped to the ground.
- Type IIa. The pet may present with increased flexion of the ankle. The injury is often at the musculotendinous junction. The ankle is slightly dropped closer to the ground.
- Type IIb. The pet may present with increased flexion of the ankle. The injury may have a ruptured tendon, however the paratenon (outer sheath around the tendon) may be intact.
- Type IIc. The pet may present with hyper flexion of the ankle and excessive digital flexion (claw stance). In this case the gastrocnemius/common tendon may be ruptured, but the superficial digital flexors remain intact.
- Type III. These patients may not present with excessive flexion of the ankle. In fact, they may have a normal stance. However, they may have tendinosis or peritendinitis that present with a swelling/thickening on the tendon.
The most common area for tendon rupture to occur is along the length of the tendon within 2 to 6 cm of the calcaneal insertion (bone at the back of the ankle). This is also the area of tendon with the poorest blood supply and therefore the least likely to heal primarily without interposing inferior scar tissue.
Treatment options are dependent on extent of injury and acuity. In acute injuries, rapid surgical repair is recommended followed by immobilization.
If complete rupture is present, surgery is the best recommended treatment option followed by immobilization and physical therapy. Surgery usually consists of reattaching the torn ends of the tendon. Surgery is best performed immediately post injury since over time the tendon retracts and bringing them together successfully can become challenging.
For partial tears, treatment options can vary from immobilization and physical therapy to a combination of surgery followed by immobilization and physical therapy depending on the extent of tear and chronicity. In some cases we have been able to heal the partially torn achilles tendon with a tarsal wrap and physical therapy alone.
In all cases whether acute, chronic, partial, or full physical therapy is needed for a successful outcome.
Immobilization: To Brace or Splint?
Immobilizations historically have been performed by rigid splints. However, orthotics (braces) are gaining popularity. Bracing can be utilized to unload the achilles tendon for the time needed to heal and then slowly reload the achilles for a more successful outcome. Imagine an injured tendon going from 0% percent loading in a cast or splint for many weeks to 100% loading in one day. There is a high chance that the achilles tendon will just tear again given that it was not given the time to rebuild strength and extensibility before weight bearing again. Achilles injuries often need physical therapy and custom devices to have a successful outcome. In a human, you can easily tell them not to jump or run on their achilles. To do slow gentle stretches and weight bearing exercises. But a dog it is hard to control their every step. So bracing provides protection to the achilles.
Bracing can be utilized post surgery or throughout the rehabilitation process if surgery is not pursued. For some patients braces are used temporary during the healing process whereas chronic degenerative achilles injuries may need a brace long term.
At your pet’s first appointment, we can help outline the different options based on the extent of injury and help guide you through the next steps appropriate for your pet. Often with these patients, we are performing a lot of laser therapy, ultrasound therapy, and shockwave therapy to bring in healthy blood flow and promote regeneration of healthy tendon tissue through recruiting fibroblasts rather than less extensible scar tissue. We often start with digital extension stretches. Once the achilles is healed we focus on strengthening the achilles tendon through isometric, then concentric, and finally eccentric exercises. We will also slowly load the achilles tendon by dynamizing the brace over time that way the Achilles doesn’t go from 0 percent loading to 100% percent loading all in one day, but slowing builds strength and extensibility over time for a higher success rate.
Healing of an achilles tendon often takes many months. These are very serious injuries and best healed if addressed quickly. If you have any questions, please feel free to reach out to us. Achilles injuries are a very common injury we see in our practice.