Deep Flexor Tendon Injury In Horses – Causes And Treatments Explained

Last Updated on June 18, 2022

The words ‘tendon injury‘ is guaranteed to strike fear into the heart of any horse owner! But what is a deep flexor tendon injury in horses, and is it a total disaster? Let’s find out!

Where Is The Deep Flexor Tendon On A Horse?

Tendons are very strong but flexible structures, which attach muscle to bone. It is easiest to think of tendons like a strong piece of rope – they can move and twist, but cannot extend or contract. The function of tendons is to support the bones and muscles when they move, by absorbing impact and providing structural support.

When the limb of a horse is under large amounts of strain, such as when galloping or jumping, the tendons absorb the energy of the movement by stretching, like a very strong elastic band. When the leg then leaves the ground, this energy is then returned to the upper leg – like a pogo stick!

The deep digital flexor tendon (DDFT) is a very strong and important tendon that extends down the back of the lower leg of all four of the limbs of a horse. Today we will be focussing on the DDFT of the forelegs, as this is a more common site of injury than the hind limb tendons.

Where Is The Deep Flexor Tendon On A Horse

In the foreleg, the DDFT starts just below the carpus, or knee, where it attaches to the deep digital flexor muscle. This large muscle attaches to the bones of the upper limb, and when it contracts it flexes the foreleg.

The DDFT runs along the back of the lower leg, behind the cannon bone. It is situated below the superficial digital flexor tendon, and the two work together to control flexion of the lower leg.

At the lower end, the DDFT runs behind the heel and attaches to the bottom of the distal phalanx, the lowermost bone in the horse’s limb that lies under the hoof wall. It also supports the navicular bone, a small but very important bone that lies below the heel bulbs.

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What Causes A Deep Flexor Tendon Injury In Horses?

A DDFT injury occurs when the tendon is put under more strain than it can cope with. This can be a sudden injury, or as a result of wear and tear over a long period of time.

A sudden DDFT injury may be due to high impact or concussion, such as when jumping or galloping on hard or soft ground. Long-term damage can be caused by poor conformation or hoof balance, or inadequate shoeing. This puts the tendon under repeated strain and may lead to injury.

When a tendon injury occurs, some of the tightly knitted fibers within the tendon are torn apart. This can lead to a hole within the tendon, known as a tear. On an ultrasound scan, this will show up as a black area within the grey tendon tissue.

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What Is The Treatment For A Deep Flexor Tendon Injury In Horses?

 There are several phases to treating a deep flexor tendon injury in horses. To start with, treatment of DDFT injuries in horses focuses on reducing the initial inflammatory reaction, as well as providing pain relief. The horse will need to be rested, and cold hosing of the limb can help to reduce pain and swelling.

Once the initial inflammatory period has passed, a rehabilitation program will be started to help the damaged tissue to repair effectively. This will normally be a controlled exercise program, with the horse kept on box rest and walked out in hand to strengthen the tendon. Any excessive work or exercise will prolong recovery and potentially lead to long-term lameness issues.

Your veterinarian may also suggest regenerative therapies to improve the healing of the tendon tissue. These come in the form of either stem cell therapy or platelet-rich plasma. These treatments do not reduce the recovery time but lead to stronger tissue repair and a reduced incidence of recurrence of the problem.

It may also be necessary to carry out remedial shoeing to treat issues that led to the original injury, such as poor foot balance. The road to recovery from a DDFT injury is long and slow, but taking the right steps is vital to give your horse the best chance of a full recovery.


So, as we have learned, a deep flexor tendon injury in horses can occur as a result of a sudden strain, or through long-term wear and tear to the tendon. These injuries are often due to excessive work on hard or soft ground, or poor conformation and foot balance. Tendon injuries in horses take a very long time to heal and require an extensive rehabilitation program to facilitate a full recovery and return to work.

We’d love to hear your thoughts on deep flexor tendon injuries in horses! Has your horse ever sustained an injury to his deep flexor tendon? Or perhaps you’re currently going through the treatment program for a horse with a deep flexor tendon injury and have a few questions? Leave a comment below and we’ll get back to you!


Can A Horse Recover From A Tendon Injury?

It is possible for a horse to make a full recovery from a tendon injury, but the likelihood of this varies according to the site and severity of the injury. It is important that treatment is initiated quickly as this improves the chances of a full recovery.

How Long Does It Take For A Deep Digital Flexor Tendon To Heal?

How long a deep digital flexor tendon takes to heal in horses depends on the extent and location of the injury. Younger horses will heal faster than older ones, but can still take up to 12 months to fully recover.

How Do You Treat A Deep Flexor Tendon Injury?

During the first few months following a deep flexor tendon injury, it will be necessary to rest the horse and provide daily controlled exercise. This may be in conjunction with other therapies prescribed by your veterinarian.

What Are 2 Clinical Signs Of A Tear In The Superficial Flexor Tendon In Horses?

If a horse has a tear of the superficial flexor tendon, you will notice a painful, hot swelling of the area behind the cannon bone. The horse will also be lame and reluctant to exercise normally.