Osteoarthritis in horses and in humans is

Histological measurements of the thickness of non-calcified and calcified cartilage, as well as the subchondral bone plate in five locations on the femoral trochlea and medial femoral condyles of species were used in preclinical studies of articular cartilage and compared to those of the human knee. Cadaver specimens were obtained of six human knees, as well as six equine, six goat, six dog, six sheep and six rabbit stifle joints (the animal equivalent of the human knee). Specimens were taken from the lateral trochlear ridge, medial trochlear ridge and medial femoral condyle. After histopathological processing, the thickness of non-calcified and calcified cartilage layers, as well as the subchondral bone plate, was measured. Average articular cartilage thickness over five locations were 2.2-2.5 mm for human, 0.3 mm for rabbit, 0.4-0.5 mm for sheep, 0.6-1.3 mm for dog, 0.7-1.5 mm for goat and 1.5-2 mm for horse. The horse provides the closest approximation to humans in terms of articular cartilage thickness, and this approximation is considered relevant in pre-clinical studies of cartilage healing.

Osteoarthritis (OA) is an important cause of pain, disability and economic loss in humans, and is similarly important in the horse. Recent knowledge on post-traumatic OA has suggested opportunities for early intervention, but it is difficult to identify the appropriate time of these interventions. The horse provides two useful mechanisms to answer these questions: 1) extensive experience with clinical OA in horses; and 2) use of a consistently predictable model of OA that can help study early pathobiological events, define targets for therapeutic intervention and then test these putative therapies. This paper summarises the syndromes of clinical OA in horses including pathogenesis, diagnosis and treatment, and details controlled studies of various treatment options using an equine model of clinical OA.

No negative effects of the microfracture technique were observed and some of the beneficial effects are the basis for recommending its use in patients cases with exposed subchondral bone.