OrthoPets Case Study: Casey

Casey is an English Pointer who is her owner’s hunting companion. A few months ago, Casey returned from the field lame in the hind end, so her owner thought it would be best to take her to the veterinarian. On gait evaluation, Casey showed a mild lameness worse in the left hind limb. While there was no evidence of increased tarsal flexion (“dropped hock” or “crab-claw” appearance), palpation of the common calcanean tendons revealed thickening bilaterally especially at the insertion of the calcaneus. Radiographs showed areas of dystrophic calcification at the insertion of the tendon. The rest of the exam was within normal limits. Casey was diagnosed with bilateral (Type 3, which is a tendinosis only with no increased hock flexion) Achilles tendonopathy, with the left being more symptomatic that the right. While Type 3 injuries can progress to more severe injuries (frequently Type 2c), surgery is generally not recommended for these injuries since the tendon is intact. Casey was placed on restricted activity and referred to a rehabilitation therapist to discuss options for this patient, specifically custom orthotic devices to reduce the stress on the Achilles tendons while they heal.

The OrthoPets tarsal orthosis creates an external moment to stabilize the tarsus when the soft tissues are not capable of stabilizing it. For cases like Casey, the first stage is generally a tarsus paw configuration with a locked-out motion limiter. This device does all the work for the Achilles mechanism allowing the early healing stages to proceed by removing tension on the impaired tendon. By doing so, the device provides an optimal environment to allow the body to heal.

Once early healing has been accomplished, the orthosis can be adjusted to allow additional flexion as the patient is able to handle some, or all, of the forces acting on the tarsus via the Achilles mechanism. Commonly used assessments to determine integrity of the Achilles tendon are palpation, clinical symptoms, goniometry, measurement of the standing angle and ideally ultrasound. When the veterinarian decides to begin additional loading of the Achilles tendon, destabilization of the device is warranted.
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Casey’s owners opted to move forward with bilateral tarsal orthotics in the hopes that the tendons will heal on their own, so that she can get back to hunting activities. Casey received bilateral articulating tarsal devices with articulating paw segments. Initially, Casey was placed in 165 degrees of tarsal extension with very limited movement allowed. As the tendon heals, Casey will gradually be allowed increased range of motion at the tarsus in increments of 10 degrees. If Casey shows signs of a full recovery, the goal is to remove the paw segment and to use the devices at times of high activity (such as hunting) to prevent further injury to her Achilles complex.

When dogs are able to demonstrate a standing tarsal angle when challenged (i.e. holding up the contralateral limb) of >135 degrees, they generally are able to transition into a sports brace. The sports brace conversion consists of grinding down the distal metatarsal shell removing the hinge attachment for the paw segment and adding a foam edge band to aid in device suspension. If this option is chosen, we will also replace the metal motion limiting component with a Dacron motion limiting strap allowing flexion to 120 degrees. Please note that due to these changes, this conversion is irreversible and therefore has to be considered carefully (if recurrence is observed a new device has to be manufactured).

If a dog does not start to show signs of recovery, the goals and device requirements need to change to match the fact that the tendon is not healing to the degree desired. This is particularly common in dogs that have more severe disease with an increased tarsal flexion angle. If this is observed, despite the environment being provided via the orthosis and the required owner compliance, it may mean that a patient will be fully reliant on the orthosis. In these cases, further or other treatment options such as regenerative medicine or surgical treatment in combination with the orthosis may be considered. Of course, tendon healing is slow and sometimes just giving it more time allows progression through the phases.