Elbow dysplasia III.: Fragmented Coronoid Process (FCP) in dogs

Elbow dysplasia is one of the leading causes of front limb lameness in dogs, and one of its most common manifestations is Fragmented Coronoid Process (FCP) or the Fragmented Medial Coronoid Process (FMCP). This developmental condition primarily affects large and giant breed dogs and results in progressive joint deterioration and osteoarthritis. Without early diagnosis and intervention, FCP leads to chronic pain, reduced mobility, and lifelong joint disease.

But what exactly is FCP? How can dog owners recognize it early? What are the best treatment and rehabilitation options? Let’s break down this complex condition, starting with the anatomy of the canine elbow joint.

Anatomy of the canine elbow joint & coronoid processes

The elbow joint is formed by three bones that must articulate perfectly to maintain smooth motion and weight distribution:

1. Humerus

• The upper arm bone, articulating with the ulna and radius to form the elbow joint.
• Bony landmarks: Medial and lateral humeral condyles, trochlea, capitulum.

2. Radius

• The primary weight-bearing bone of the forelimb, located laterally.
• Bony landmarks: Radial head (articulates with the humerus and ulna).

3. Ulna

• The stabilizing bone of the forearm, positioned medially.
• Bony landmarks:
  • Olecranon process (insertion for the triceps brachii).
  • Trochlear notch (fits into the humeral condyle for articulation).
  • Anconeal process (important for elbow stability).
  • Medial and lateral coronoid processes (prevent excessive joint rotation).

The medial coronoid process (MCP) of the ulna plays a crucial role in joint stability by preventing excessive rotation of the radius. In dogs with FCP, this structure cracks or fragments, leading to pain, inflammation, and abnormal wear of the joint surfaces.

What is a Fragmented Coronoid Process (FCP)?

FCP occurs when the medial coronoid process (MCP) of the ulna fails to fuse correctly or fractures due to excessive stress. This loose fragment within the joint causes irritation, inflammation, and cartilage damage, accelerating the onset of elbow osteoarthritis.

Over time, FCP leads to:

✔️ Abnormal joint wear
✔️ Painful bone-on-bone contact and lifelong chronic pain
✔️ Loss of cartilage and joint function
✔️ Development of osteoarthritis (OA)

What Causes FCP?

Several factors contribute to FCP development:

1. Genetic predisposition – Strong hereditary component in certain large breeds.
2. Elbow incongruence – If the radius and ulna are not perfectly aligned, excessive stress is placed on the coronoid process.
3. Rapid growth & excessive weight – Overnutrition in puppies leads to abnormal joint development.
4. Repetitive high-impact activity – Excessive running, jumping, or rough play in young dogs may contribute to microtrauma.

Breeds Predisposed to FCP

FCP is most common in large and giant breeds, especially those with rapid bone growth:

• Labrador Retrievers
• Golden Retrievers
• Rottweilers
• German Shepherds
• Newfoundlands
• Bernese Mountain Dogs
• Border Collies
• Saint Bernards

How can you detect elbow pain?

Well... FCP most typically begins to cause pain and complications between 3-13 months or around 4-5 years old. Watch out, dogs are masters at hiding pain, so you have to be better than Sherlock Holmes, but early signs of elbow discomfort include: rotation of the paws towards external side (extero rotation) 

Plus...

✔️ Mild to moderate lameness, especially after exercise.
✔️ Stiffness in the morning or after resting.
✔️ Reluctance to jump, play, or go upstairs.
✔️ Outward rotation of elbows & paddling gait.
✔️ Pain when flexing or extending the elbow, when pushing the medial ("inward" part) the dog might try to get rid of the palpation.
✔️ Swelling or thickening of the joint.

If left untreated, FCP progresses into severe arthritis, significantly affecting mobility and quality of life.

Diagnosis of FCP

Accurate diagnosis requires imaging techniques:

X-rays: Can reveal joint incongruence and secondary arthritis.
CT scan: The gold standard for detecting small coronoid fragments.

Treatment options for FCP

Surgical treatment

💉 Fragment Removal (Coronoidectomy): The most common surgical approach, removing the loose coronoid fragment to alleviate pain.
1. Subtotal Coronoid Ostectomy (SCO): Removal of damaged coronoid bone in more severe cases.
2. Proximal Ulnar Osteotomy (PUO): If elbow incongruence is present, this procedure corrects weight-bearing stress on the coronoid process.

Surgery is recommended for young dogs and those with severe pain. Delaying treatment leads to irreversible osteoarthritis.

Rehabilitation & Physiotherapy for FCP

For both post-surgical recovery and conservative management, physiotherapy is essential to reduce pain, restore function, and improve joint stability.

1. Manual Therapy & Fascia Release – Reduces muscle tension and compensatory gait patterns.
2. Targeted Strengthening – Focus on stabilizing the triceps brachii, biceps brachii, pronator teres, supinator, and forearm flexors.
3. Low-Impact Exercises – Cavaletti training, weight shifting, and controlled leash walks improve joint function.
4. Laser & Shockwave Therapy – Reduce inflammation, improve circulation, and promote healing.
5. Joint Supplements – MSM, collagen type 2, hydrolized collagen, hyaluronic acid, c-vitamin, chondroitin and glucosamine, curcumin + piperin should be fed.

Scientific References & Book Recommendations

📖 Books:

• "Canine Rehabilitation and Physical Therapy" – Darryl L. Millis & David Levine
• "Advances in Canine Orthopedics" – Martin Fischer

📄 Studies:

• Cook CR, Cook JL. (2009). "Elbow Dysplasia in Dogs: Diagnosis and Management." Veterinary Surgery Journal.
• Fitzpatrick N, Smith TJ. (2017). "Coronoid Disease and Osteochondrosis in Large Breeds." Veterinary Orthopedic Research.
• Wind A.P. (1986). "Pathogenesis of Elbow Dysplasia." Journal of Veterinary Medicine.

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