The patella is the kneecap and is a prominent landmark of the stifle. It connects the lower limb to the quadriceps muscles in the upper thigh through its attachments to the patellar ligaments, allowing extension of the lower limb and enabling weight bearing in the hind limb.

The patella is a critical part of the hind limb reciprocal apparatus. Disruption of this apparatus results in the horse's inability to bear weight.

Luckily, the patella is not commonly injured. Its position resting within the grooves of the lower femur (trochlear grooves) is very stable, so it is unlikely to be damaged except through direct trauma. Fractures of the patella (the kneecap) are most commonly caused by a kick from another horse. It also occurs in jumping horses that suffer a direct impact from hitting a jump.

Patellar fractures take a variety of configurations. The specifics of the fracture is determined with veterinary examination and thorough imaging, primarily x-ray and ultrasound. Identifying the specific nature of this injury is important in determining the best treatment plan and prognosis.

Treatment may be conservative (rest and time) in some cases. Surgery is required in other cases.