Subchondral cystic lesions (osteochondrosis) of the femoral heads in a horse.

This research article investigates a case where bilateral subchondral cystic lesions in a horse’s femoral heads led to lameness. These lesions also caused degenerative disease in the left coxofemoral joint and were confirmed though multiple diagnostic methods. The study suggests including these lesions in the differential diagnosis for equine lameness in the hind limb upper section.

Overview of the Horse’s Condition

• The study focuses on a horse that exhibited lameness due to bilateral subchondral cystic lesions found in its femoral heads. These lesions are cavities located underneath the cartilage of a joint, filled with fluid. When they occur in the femur (the large bone at the horse’s hind leg), they can cause significant discomfort and mobility issues.
• Beyond causing lameness, the lesions also resulted in a degenerative disease in the left coxofemoral joint. The coxofemoral joint is the horse’s hip joint, and degenerative diseases in this area can progressively worsen over time, leading to increased pain and decreased functionality.

Diagnosis Process

• The researchers confirmed the source of the horse’s lameness via a three-pronged diagnostic approach. They used intra-articular anesthesia, which is the injection of anesthesia directly into a joint. This can be done to determine if the horse’s discomfort originates from the joint, as the anesthesia should alleviate the pain temporarily.
• Joint fluid analysis was another part of the diagnostic approach. By examining the fluid found within the joints, vets can identify signs of inflammation, infection, or degenerative diseases. In this horse’s case, the fluid analysis provided key evidence towards the existence of a degenerative disease in the left coxofemoral joint.
• The last part of the diagnostic process was the use of radiography, or X-ray imaging. X-rays allow for visualization of the bones and any potential deformities or lesions they may be carrying.

Differential Diagnosis for Equine Lameness

• The findings from the study suggest that subchondral cystic lesions located in the femoral head should be added to the list of potential causes when diagnosing equine lameness that is localized in the upper portion of the hind limb.
• A differential diagnosis is the process through which veterinarians or doctors differentiate between two or more conditions that share similar symptoms. In this instance, the leg lameness could be caused by various factors, with subchondral cystic lesions being one of the potential causes.