1. Conditions of the stifle – OCDs AND BONE CYSTS
EQS 200

2. 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

3. 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!

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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
Loose, detached tissue is elevated and removed while fragments hanging off or floating are removed
The defected area is debrided down to healthy tissue

11. 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

12. 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

13. 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

14. 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

15. 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, months of paddock rest

16. 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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