Conditions of the stifle – OCDs AND BONE CYSTS EQS 200

The stifle consists of 3 bones and 3 joints The Stifle – a review The stifle consists of 3 bones and 3 joints Bones Tibia Femur Patella Joints Femoropatellar Lateral femotibial Medial femorotibial Largest! Menisci (thick fibrous cartilage) is present on the top of the tibia for shock absorption and preventing friction between joint surfaces

Osteochondrosis of the stifle Osteochondrosis is a defect of developing bone that affects joint cartilage and subchondral bone that is beneath the cartilage What type of horses is it commonly seen in? The stifle is one of more commonly affected joints and is a common cause of stifle lameness Young & growing!

OCD of the stifle Osteochondritis dissecans (OCD) is a type of osteochondrosis lesion 60% of cases involve yearlings or younger! Involves a fragment of bone and cartilage breaking off the joint surface and remain loosely attached Results in… Synovitis Joint inflammation Very commonly seen at the femoropatellar joint

Causes Nutrition Excessive Loading Gaining body weight too quickly will result in overloading and/or damaging growing bones Excess carbohydrates can impair the production of thyroid hormones needed for growth Excess or deficiency of Calcium or Phosphorus can interfere with bone production Copper deficiency can result in fragile and weak bone Can harm the developing cartilage Trauma or excessive weight from large, overfed foals can harm the blood supply canals to cartilage and bones

Infections can affect bone development and growth Contributing factors Conformation & congenital deformities can overload part or all of a joint surface Gender Male or Female? Infections can affect bone development and growth Corticosteroids can interrupt normal cartilage and bone development

Clinical Signs Joint effusion A mild or moderate lameness may not appear until the horses workload increases Stiff and shortened stride is more common early on Often bilateral involvement Severely affected horses will have a “bunny hop” action behind

Diagnosis Radiographs are the best diagnostic tool for OCDs because they provide the most useful information regarding specific lesion location and size Often show obvious changes but flattened or irregular bone surface may only be seen Damage found during surgery is often more severe then what can be detected by radiograph

OCD treatment can follow a conservative or surgical approach Best for foals and horses under 12 months due to greater opportunity to influence bone development Modify the diet by reducing large weight gain, correcting Ca:P ratio and checking for deficiencies or excesses Rest from training NSAIDs can be used sparingly

Surgery allows for a good view of the joints cartilage and surfaces which can help determine best post-surgery management Surgical Approach When swelling and lesions are prominent, arthroscopic surgery is often recommended During surgery the joint is thoroughly explored and suspicious lesions are probed http://www.youtube.com/watch?v=HSz9alfO5As http://www.youtube.com/watch?v=5TJta3dq-xQ Loose, detached tissue is elevated and removed while fragments hanging off or floating are removed The defected area is debrided down to healthy tissue

Prognosis Depends on location, type and number of lesions, and length of time between occurrence and treatment Once fragment is removed athletic prognosis is good A horse that was treated surgically will need 2 weeks of stall rest followed by 2-3 months of walking and restricted exercise

Bone cyst Less common than an OCD but can be more of a problem Another type of Osteochondrosis lesion A bone cysts is a circular or oval-shaped cavity that will filled with fluid or other soft material just beneath the joint surface Stifle is the most common location Commonly found in horses 3 years old or younger

Development & Pain Bone cysts can develop due to… A small part of the growth cartilage failing to ossify Trauma or overloading of growth cartilage may damage or restrict blood flow to the bone which results in non-fully formed bone Joint cartilage defect that damages the underlying bone Why does it cause pain? Due to pressure buildup inside of cyst

Signs & Diagnosis Radiographs are the best diagnostic tool Shortened stride that may be intermittent and increase after start of training Grade 2 – 3 hind limb lameness Joint effusion Radiographs are the best diagnostic tool Often appears as a lucent area

Treatment Surgery involves cleaning out the cyst and drilling small holes around it or drilling through the cysts and filling the cavity with a bone graft Like OCDs, treatment can follow a conservative or surgical approach Heals with altered cartilage that is not 100% functional and may predispose to chronic joint issues Conservative Surgical Rest with or without joint medications and NSAIDS for at least 6 months Will remove the contents from the cyst to allow lesion to heal Surgery often results in better success than conservative approach 2-4 weeks of stall rest, 4-6 months of paddock rest

Prognosis Younger and smaller lesions will benefit from conservative treatment but a surgical approach results in fairly good outcomes for an athletic career

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