Tendon Trauma in Dogs

Tendons are composed of strong collagen fibrils which, when grouped together, are referred to as collagen fiber. These dense collagenous fibers are enclosed in a thick connective tissue known as an epitenon.

Physiologically, the tendons in a dog’s body connect to muscle and to bone thereby allowing force to be generated, allowing muscle and bone to withstand tremendous pressure. However, once pressure and force exceed a certain limit then injury of the supporting tendon may occur.

A Tendon trauma may be defined as a laceration, inflammation or rupture of the tendon to the joint that results in severe pain and lameness, particularly in larger, heavier dogs.

• Lameness defined as the inability to perform regular moving functions
• Pain in the localized area
• Resistance to flex or extend the related joint
• Inflammation of the affected limb may occur
• In regards to Achilles’s tendon injuries. the animal will drop their paw flat on the ground and may drag the foot; this is referred to as a 'plantigrade stance'

Types

Because tendons connect muscle to bone all over the body, tendon damage can occur in many locations. Two types of tendon trauma seen in canines are:

• Injury to the Achilles tendon
• Bicipital tenosynovitis

Achilles tendon injuries can further be classified as either traumatic (resulting from physical injuries) and atraumatic (chronic due to age). Damage to the Achilles tendon may be more common in larger breed dogs such as Doberman and Labradors.

Bicipital tenosynovitis refers to the inflammation of the biceps brachii tendon and muscle and most commonly affects larger, mature dogs. Inflammation of the biceps brachii tendon is not the only form of tendon damage that can occur. Dogs may also experience rupture and hardening of this tendon.

Causes of tendon trauma may either be degenerative and chronic with aging animals or a result of extensive physical exertion. Some causes may include:

• Straining and over-working of the muscles and associated joints causing tendons to stretch beyond optimal lengths; for example, racing and working dogs tend to fall victim to over working tendons
• Laceration of tendons may result in an increase in pressure among tendons, a decrease in blood circulation, inflammation and the possibility of bacterial infection

In order to diagnose tendon injuries your veterinarian may conduct a physical exam and ask for the history, duration and onset of the particular injury. They will carefully palpate the area to determine if swelling or malformation of muscle is prominent.

X-rays may determine if bone fragments have impacted the nearby muscle. Ultrasonography may be performed in order to determine the severity and/or possibility of ruptured tendons. However, studies suggest that arthroscopy is the optimal diagnostic tool for determining joint health.

Surgical intervention is the method of choice by most veterinarians when treating severe tendon injuries, particularly ruptures. The aim of most tendon surgeries involves reattachment of tendon to bone and can be done through suturing and other forms of scaffolding. Suturing may involve either a loop pulley or locking loop pattern. These methods of suturing have been suggested to improve mobility and are associated with quicker recovery of associated joints.

For mild cases involving straining or spraining of tendons, veterinarians may simply advise on rest and oral medicine. 

If the tendon is facing severe inflammation (bicipital tenosynovitis) then your veterinarian may administer a long course of NSAIDs (non-steroidal anti-inflammatory medication) and opium in order to restore blood flow. Some examples of NSAIDs used are: Deracoxib, carprofen, etodolac and ketoprofen.

Any form of tendon trauma may take up to 5 to 12 months for recovery depending on the severity of the case and the owner’s willingness to aid in recovery.

Postoperative care may involve the use of bio-scaffolding to promote stabilization of the joint. This may include the use of materials such as polypropylene mesh and bone plates; the use of these implants may, however, pose a risk due to the body’s’ immune system reacting badly to foreign objects. Thus, your veterinarian may require a follow up within 14 days to view the efficacy of the graft.

Your veterinarian will suggest restricting the dog from strenuous activity. Ideally, owners need to avoid allowing the dog to run and jump, to avoid excessive loading (for example, in sled dogs) and any physical activity that may over strain the muscle and joints.

It is important to realize that complete restriction of slow movement and exercise will not aid in recovery as your dog may begin to unconsciously depend on the support of scaffolding. Thus, over time the veterinarian will slowly begin to decrease the amount of support given to the affected joint.

In order to rebuild muscle structure and enhance recovery, a slow progressive exercise regime should be considered 8 weeks after surgery. This may include a 6 week healing process involving:

• Hydrotherapy - this may include swimming in a controlled environment with owner
• Physiotherapy - particularly focusing on flexion and extension of the joints
• Slow walking on leash for short periods of time
• Warm packs to stimulate blood flow to the affected area

In regards to dietary changes, your vet may recommend supplements rich in Glucosamine, Methylsulfonylmethane and Hyaluronic acid. A few possible therapeutic supplements may include Tri-acta H.A, Glyco-Flex 2 and Traumeel.

It is estimated that approximately 70 to 94% of dogs may regain adequate mobility within 6 to 9 months depending on the efficacy of therapy.