Approach to eq OCD

Presenting signs

·    Aged 2yrs

·    Varying degrees of joint effusion, lameness, heat

·    Positive to joint flexion

History

·    When did signs appear? – from birth, when started exercising, randomly?

·    Any abnormalities during birth/early life?

·    What signs have they seen?

Investigation

·    Palpation

·    Lameness exam

·    Regional anaesthesia

·    Radiographs – looking for lesions/fragments, pathology

·    Ultrasound

Management

Choice depends on disease severity, horse and owner factors

·    Conservative – no tx, just monitor and wait and see

o  E.g. if only thickened cartilage

·    Medical – intra-articular mediation, e.g. steroids, stem cells, lubricants

·    Surgical – arthroscopic fragment removal in OCF/OCD, debridement of diseased cartilage and necrotic subchondral bone

·    Euthanasia – if poor QoL

Pathogenesis

·    Focal failure of endochondral ossification at epiphyseal growth cartilage (cartilage laid down but not ossified into bone)

o  Due to: genetics, over nutrition, rapid growth, mineral imbalances

·    Outcomes of OC lesions:

o  Remains as OC lesion

o  Lesion progresses to OCD (fissure appears in cartilage, fragmentation can occur)

o  Lesion can progress to SCL (necrosis of thickened cartilage)

OCD

·    Pathogenesis:

o  OC causes weakening and necrosis of cartilage at end of epiphysis ®  fissures appear

o  Mineralisation occurs within lesion, fissures break free ® fragmentation

·    Predilection sites: stifle and hock (shearing forces)

·    Clinical signs: moderate lameness (worse after flexion), joint effusion, heat

o  Signs can appear straight away (approx. 1yr old), when horse begins to work, or never (lesions remain subclinical)

OCF

·    Pathogenesis:

o  Small piece of periarticular bone fractures off in traumatic manner

§ As part of OA

§ Following direct trauma

§ As an avulsion (associated with ligament insertion)

·    Clinical signs: moderate lameness (worse after flexion), joint effusion, heat

o  Signs can appear straight away (any age), when fragment contributes to further OA (later on) or never (lesions remain subclinical)