The fetlock is a key joint in a horse’s leg, and it’s especially prone to injuries, particularly in horses that do a lot of athletic work. These injuries can be minor, but they can also be serious enough to end a horse’s career.
This article will take a closer look at the equine fetlock, including the anatomy of the joint, common injuries that affect it, how those injuries are diagnosed and treated, and what you can do to prevent them. We’ll also discuss the importance of early detection and getting veterinary help as soon as possible.
Understanding the fetlock is essential for horse owners, trainers, and anyone else working with horses. By understanding the fetlock, you can take steps to care for your horse proactively and minimize the risk of injury.
Anatomy and Biomechanics of the Fetlock
To understand the fetlock and its vulnerabilities, it helps to understand its construction.
Skeletal Structure
The fetlock is made up of bones and soft tissues:
- Metacarpophalangeal/Metatarsophalangeal Joint: This is where the cannon bone (either metacarpal or metatarsal III, depending on whether we’re talking about a foreleg or hind leg) connects to the proximal phalanx (P1), which is also known as the long pastern bone.
- Sesamoid Bones: Two sesamoid bones connect with the far end of the cannon bone to form part of the joint. The suspensory ligament gets some helpful leverage from these bones.
Soft Tissue Structures
Ligaments, tendons, joint capsules, and synovial fluid work together to support the fetlock.
- Ligaments: Collateral ligaments keep the sides of the joint stable. The suspensory ligament is essential to keeping the fetlock from overextending.
- Tendons: The flexor tendons (deep and superficial digital flexor tendons) run behind the fetlock, while the extensor tendons run along the front.
- Joint Capsule and Synovial Fluid: The joint capsule holds everything together and contains synovial fluid, which lubricates the joint and feeds nutrients to the cartilage.
Biomechanical Function
- Shock Absorption: The fetlock plays a vital role in shock absorption.
- Range of Motion: The fetlock allows for a wide range of flexion and extension, which contributes to the horse’s way of moving. The forces exerted on the fetlock can be twice the horse’s body weight.
How to recognize a fetlock injury
If a horse injures its fetlock, the most obvious sign is usually lameness. The horse may limp or be unwilling to put weight on the affected leg. The degree of lameness usually reflects the severity of the injury, and it may become more obvious after exercise.
Another common sign is swelling around the fetlock joint. If you touch the area, it might also feel hot or tender.
You may also notice changes in the horse’s gait, such as:
- A shortened stride
- Reluctance to bear weight on the leg
- Stiffness in the joint
Other potential signs include joint effusion (fluid buildup), pain when you touch specific parts of the fetlock, or even visible deformities in severe cases.
Common Types of Fetlock Injuries
Because the fetlock joint is so weight-bearing and crucial for movement, it’s vulnerable to a number of different injuries. These can be broadly categorized as soft tissue injuries, bone-related injuries, and other conditions.
Soft Tissue Injuries
Soft tissue injuries involve damage to the ligaments, tendons, and other soft structures around the fetlock.
- Suspensory Ligament Desmitis: This involves inflammation and damage to the suspensory ligament, which runs down the back of the cannon bone and supports the fetlock. Injuries can range from mild strains to complete tears. Degenerative Suspensory Ligament Desmitis (DSLD) is a particularly serious and often career-ending condition where the ligament progressively weakens and degrades.
- Digital Sheath Tenosynovitis: This is inflammation of the tendon sheath surrounding the flexor tendons as they pass over the back of the fetlock. It’s often caused by repetitive strain or trauma. Sometimes, it’s referred to as “windpuffs” or “windgalls,” although those terms can also refer to other types of swelling in the fetlock region.
- Collateral Ligament Injuries: The collateral ligaments run along the sides of the fetlock joint, providing stability. Sprains or tears of these ligaments can result from sudden twisting or trauma to the joint.
Bone-Related Injuries
Bone-related injuries involve fractures or degenerative changes within the bones of the fetlock joint.
- Chip Fractures: These are small fractures of the joint cartilage and the bone underneath. They often occur due to repetitive stress or trauma, especially in athletic horses.
- Sesamoid Fractures: The sesamoid bones are two small bones located at the back of the fetlock, embedded within the suspensory ligament. Fractures of these bones are common in racehorses and other high-speed athletes due to the tremendous forces placed on the fetlock during exercise.
- Osteoarthritis (OA): Also known as degenerative joint disease, osteoarthritis affects the cartilage and bone within the joint. It can be caused by previous injuries, repetitive stress, conformational issues, or simply the wear and tear of aging.
Other Conditions
These are conditions that affect the fetlock but don’t fall neatly into the soft tissue or bone categories.
- Villonodular Synovitis: This is an inflammatory condition affecting the synovial membrane, which lines the joint capsule. It can cause swelling, pain, and lameness.
- Physitis: This is inflammation of the growth plates in young, growing horses. While it can occur in other joints, it can also affect the fetlock.
How are fetlock problems diagnosed?
If your horse is showing signs of a fetlock injury, your vet will likely start with a comprehensive exam. This will include watching your horse move at a walk, trot, and canter, as well as feeling the fetlock for any swelling, pain, or heat. The vet will also check the surrounding structures.
To get a better look, your vet might use:
- X-rays: These help to see bone damage, like fractures or arthritis.
- Ultrasound: This is good for checking soft tissues such as ligaments and tendons.
- MRI: This gives detailed images of both bone and soft tissue.
- CT Scans: For evaluating complex fractures.
Other tests could include nerve blocks to pinpoint the source of the pain and analyzing the fluid inside the joint to check for inflammation or infection.
Treatment and Management of Fetlock Injuries
How a fetlock injury is treated depends on the type and severity of the injury. Here’s an overview of common treatment approaches:
Conservative Treatment
Often, the first step in treating a fetlock injury is a conservative approach. This means focusing on non-surgical methods to allow the injury to heal.
- Rest: Rest is absolutely critical to allow the tissues to repair themselves. How long the horse needs to rest depends on the seriousness of the injury.
- Cold therapy: Applying ice or cold packs to the fetlock reduces inflammation and eases pain.
- Anti-inflammatory medications: Non-steroidal anti-inflammatory drugs (NSAIDs), like phenylbutazone (“Bute”) or firocoxib (Equioxx), are frequently used to relieve pain and reduce inflammation. In some situations, corticosteroids may be considered.
- Supportive bandaging or splinting: Bandages or splints can provide support and stability to the joint, helping to prevent further injury.
Surgical Intervention
In some cases, surgery may be necessary to address the fetlock injury.
- Arthroscopic surgery: This minimally invasive procedure can be used to remove chip fractures, repair damaged cartilage, or address other problems inside the joint.
- Fracture repair: Surgery may be needed to stabilize sesamoid fractures or other bone fractures in the fetlock.
- Surgical fusion (Arthrodesis): In severe cases of osteoarthritis where the joint is severely damaged, fusing the joint may be an option to alleviate pain.
Regenerative Therapies
Regenerative therapies aim to promote healing and tissue repair within the fetlock joint.
- Platelet-Rich Plasma (PRP): This involves injecting concentrated platelets into the injured area to stimulate tissue healing.
- Stem Cell Therapy: Stem cells are injected to help regenerate damaged tissues within the joint.
- Other Biologics: Other biologic therapies, such as IRAP (Interleukin-1 Receptor Antagonist Protein), may also be used to reduce inflammation and promote healing.
Rehabilitation and Physical Therapy
Rehabilitation is a crucial part of the recovery process after a fetlock injury. It focuses on gradually rebuilding strength, flexibility, and function in the joint.
- Controlled Exercise: A carefully planned exercise program, with gradually increasing levels of activity, helps rebuild strength and flexibility in the fetlock.
- Physical Therapy Modalities: Various physical therapy modalities, such as therapeutic ultrasound, laser therapy, massage, and PEMF (Pulsed Electromagnetic Field) therapy, can be used to promote healing and reduce pain.
How to protect your horse’s fetlocks
You can take a number of steps to protect your horse’s fetlocks and help prevent injuries:
Proper Training and Conditioning
- Increase the intensity and duration of exercise gradually to avoid overstressing the joint.
- Develop balanced training programs that focus on both strength and flexibility.
Appropriate Footing
- Avoid exercising horses on excessively hard or uneven surfaces.
- Good footing reduces the risk of concussion and strain.
Corrective Farriery
- Maintain proper hoof balance to distribute weight evenly and reduce stress on the fetlock.
- Schedule regular trimming and shoeing appointments with a qualified farrier.
Nutritional Considerations
- Provide a balanced diet to support bone and soft tissue health.
- Talk to your veterinarian about supplements such as glucosamine, chondroitin sulfate, and hyaluronic acid.
Regular Veterinary Check-ups
- Schedule regular veterinary exams to allow for early detection of subtle lameness or other issues.
- Proactively manage any identified problems.
Long-Term Management and Prognosis
If your horse has a fetlock injury, you’ll need to monitor its condition carefully. This includes:
- Regular lameness and joint health check-ups: Your veterinarian can assess the horse’s progress and adjust the treatment plan as needed.
- Periodic veterinary exams: These exams can help detect any new problems early on.
- Customized exercise programs: The program should be tailored to your horse’s specific needs and limitations, with a gradual increase in exercise intensity.
- Maintenance therapies: Joint injections or oral supplements may help manage pain and inflammation.
The prognosis for a fetlock injury depends on the type and severity of the injury. Early diagnosis and treatment can improve the chances of a full recovery. However, some injuries may lead to chronic lameness or a reduced ability to perform athletically.
Wrapping Up
The fetlock is a complex and critical joint in horses, and it’s also prone to injury. Because of this, it’s important for horse owners and equine professionals to understand the fetlock’s anatomy, the injuries that commonly occur there, and strategies for treatment and ongoing management.
Prompt detection of problems, appropriate veterinary care, and a commitment to preventative measures are essential for keeping your horses’ fetlocks healthy and supporting their best athletic performance. If you’re concerned about your horse’s fetlocks, talk with your vet to develop a plan.