Pancarpal arthrodesis, a surgical stabilization of the carpus (wrist) joint, is commonly recommended for dogs suffering from carpal hyperextension injuries. This guide explains the condition, the anatomy of the carpal joint, and the rationale behind the treatment.

Anatomy of the Carpus

The carpus in dogs and cats is analogous to the human wrist, comprising a series of small bones that allow for flexibility and movement in the front leg.

Key Structures:

1. Proximal carpal bones: The row of larger bones closest to the forearm.
2. Distal carpal bones: The row of small bones connecting the metacarpal bones (similar to our hand bones) to the proximal carpal bones.
3. Palmar fibrocartilage: A strong, fibrous layer primarily responsible for stabilising the carpal joint.
4. Palmar ligaments: Bands of tissue connecting the carpal bones on the underside, providing additional stability and flexibility.

Carpal hyperextension injuries result in damage to the fibrocartilage and ligaments that stabilize the carpal joint, making it unstable and painful. These structures unfortunately cannot heal with enough strength to keep the carpus stable.

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Treatment: Pancarpal Arthrodesis

Pancarpal arthrodesis involves fusing the carpal bones, effectively eliminating motion in the joint to provide pain relief and stability. The cartilage is removed from the joint surfaces and a bone graft (from the shoulder) is placed in the joint space. The joint is then held in place with plates and screws.

This procedure is the primary treatment of choice for severe carpal hyperextension injuries, with high success rates leading to improved limb function and pain relief. While the idea of fusing the entire joint may seem extreme, this is a very well-tolerated procedure. Many patients do not have an obvious difference in leg use after the surgery.

Care After Pancarpal Arthrodesis

• Week 1-2: Restrict movement. Short, supervised outdoor breaks for bathroom needs. Observe for any signs of infection or unusual appearance at the incision site. A post-operative check will be scheduled around the 2-week mark to ensure proper healing.
• Week 3-4: Begin reintroducing gentle walks, ensuring no jumps or strenuous activities.
• Week 5 onwards: The duration of leash walks can be gradually increased, and we will guide you through this. We will see your pet at the eight-week mark for some further x-rays to monitor healing. We might need to take some further X-rays at around twelve to sixteen weeks after surgery.

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Potential Complications of Pancarpal Arthrodesis

While the procedure generally results in positive outcomes, potential complications include:

1. Non-union: This refers to the carpal bones failing to fuse appropriately.
2. Infection: As with any surgical intervention, there's a possibility of infection at the surgical site. Indicators can include redness, swelling, warmth, and discharge.
3. Implant failure: Occasionally, the screws or plates used might break or become loose, necessitating another surgery.
4. Decreased limb use or altered gait: Rarely, some patients might have changes in their walking pattern post-surgery.

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Remember, while there are potential complications, pancarpal arthrodesis has a high success rate and improves many patient's quality of life. Around 10% of patients will have a complication that will require a second surgery. While this can be daunting, in the majority of cases the complication can be successfully resolved.

Your pet’s full return to normal activity may take several months, but with diligence and proper care, they can enjoy a pain-free, active life once again.