Common Knee Injuries in Horses: Causes and Care

Understanding horses' knee injuries is key to keeping our equine friends sound and comfortable. The horse’s knee, known as the carpus, is particularly vulnerable to several injuries that can significantly affect their movement and performance. These injuries often result from trauma, repetitive stress, or underlying conformation faults. In this guide, we explore the most common knee problems in horses, their symptoms, treatments, and prevention strategies.

1. Hygroma: Fluid Buildup and Swelling

A hygroma is a swelling at the front of the horse’s knee caused by fluid accumulation. This often arises from repeated trauma such as knocks, falls, or continuous banging of the knees against hard surfaces like stable walls or partitions during transportation. While hygromas are usually painless and do not interfere heavily with soundness, they can be unsightly and occasionally indicate deeper issues.
Veterinary treatment typically involves draining the fluid followed by applying a compression bandage to prevent re-accumulation. It is important to treat hygromas early to reduce the risk of complications, such as infection or tendon involvement. Persistent hygromas may suggest underlying conditions like osteoarthritis or joint capsule restrictions that need further investigation.

2. Carpal Chip Fractures: Small Bones Breaking Off

Young and active horses, particularly those in training or turned out with other youngsters, often suffer from carpal chip fractures. These are small fragments of bone that break off inside the carpal joint, commonly due to repetitive concussion or traumatic impact. Such fractures often lead to pain, swelling, and lameness if untreated.
There are two frequent types of carpal fractures:

• Carpal slab fractures – where a slice of a carpal bone detaches;
• Accessory carpal bone fractures – affecting a smaller, separate bone on the side of the joint.

Surgical removal of these fragments is often recommended to prevent joint degeneration and chronic arthritis. However, the decision depends on the size of the fragment and scar tissue presence. Early veterinary diagnosis using X-rays or ultrasounds is essential for successful treatment.

3. Acute Carpitis: Joint Inflammation

Carpitis refers to inflammation of the knee joint resulting from acute injury or trauma. This can cause severe swelling, heat, pain, and decreased mobility. Prompt veterinary intervention is vital to reduce joint damage and to prevent long-term lameness.
Diagnosis includes radiography and ultrasound scanning to evaluate both bone and soft tissues. Treatment typically involves cold therapy, a course of non-steroidal anti-inflammatory drugs (NSAIDs), and a period of box rest or restricted movement to allow healing.

4. Soft Tissue Injuries: Ligaments and Tendons

The carpus consists of numerous ligaments, tendons, and cartilage structures that can suffer from strains, sprains, or tears. Soft tissue injuries often result from trauma or overuse and may present as swelling, heat, lameness, or joint instability.
Ultrasound examination is the key diagnostic tool for identifying the extent and type of soft tissue damage. Treatment focuses on reducing inflammation, supporting healing with rest, and in some cases, physiotherapy or regenerative therapies.

5. Carpal Osteoarthritis: Degenerative Joint Disease

Osteoarthritis (OA) is a progressive and degenerative condition, among the leading causes of chronic knee lameness in horses. It is characterised by cartilage breakdown, inflammation, pain, and bony growths (osteophytes) within the joint, impairing mobility.
OA commonly develops after prior injury or chronic stress on the knee. Horses with conformational defects such as "offset knees" may be at higher risk due to abnormal joint loading.
Management includes NSAIDs for pain relief, joint supplements to support cartilage health, weight management, and tailored exercise programs. In severe cases, surgical options such as joint fusion may be considered to improve quality of life.

Prevention and Responsible Ownership

Responsible horse care and management can reduce the risk of these knee injuries. Providing safe turnout areas, avoiding rough surfaces, careful transport to prevent repetitive trauma, and early veterinary assessment of any swelling or lameness are crucial steps.
Regular veterinary check-ups and timely treatment of minor injuries can prevent progression to debilitating conditions like osteoarthritis, ensuring your horse's welfare and long-term soundness.

Conclusion

The equine knee is a complex and vital joint that undergoes significant stress during training and performance. Common injuries include hygroma, carpal chip fractures, acute carpitis, soft tissue injuries, and osteoarthritis. Early diagnosis, appropriate treatment, and careful management are essential to protect your horse's joint health and soundness.
Always consult with your vet promptly if you notice swelling, lameness, or changes in movement. Together, you can work towards the best outcome for your horse’s comfort and performance.