The coffin joint is the lowest joint in the equine limb, and is mostly surrounded by hoof. Swelling in the coffin joint can be seen right around the hairline of the hoof (coronet band).
Low ringbone is the horseman’s term for the development of bone deposits around the coffin joint, where P2 (the short pastern bone) and P3 (the coffin bone) meet. The condition tends to be more common in the front limbs.
As a result of injury, stress or trauma to the coffin joint, the body reacts by laying down large quantities of bone in an “attempt to stabilize” the joint. This is associated with deposits or ridges of bone along the front or side of the coronary band, local pain, heat and gradually worsening lameness, and destruction of the cartilage of the joint.
This degenerative process is seen as a consequence of traumatic injury, including coffin bone fractures and chronic stress and wear, especially in horses with poor lower limb conformation. It is more common in heavy breeds and those that heavily impact the forelimbs in their work, such as jumpers.
By the time the hard swelling is visible just above the coronet band, the condition is usually far advanced and irreversible. However, when caught early, the disease process can be slowed with proper treatment.
Diagnosis may be obvious on clinical exam but may require blocking with x-ray and other imaging.
Treatment includes the large variety of treatments available for osteoarthritis.
Other Diagnoses Considered
Treatments May Include
Prognosis & Relevant Factors
Guarded to poor in the advanced stages. This disease is career-limiting for the majority of affected horses.
The coffin joint is a high motion joint. Unlike the pastern joint, which has relatively small range of motion, surgical or chemical fusion of the coffin joint is not appropriate.
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