Signs of implant failure after orthopedic surgery

After orthopedic surgery in dogs and cats, most pet owners expect a smooth recovery, where their animal regains mobility and returns to normal life.

However, while modern veterinary orthopedic implants are designed to be strong, biocompatible, and long-lasting, complications can sometimes occur — and one of the most serious issues is implant failure. Recognizing the signs early is crucial to avoid prolonged discomfort, irreversible damage, or the need for additional surgery.

Implant failure can manifest in subtle or obvious ways. One of the most common early signs is a return of lameness in the operated limb. If your pet was improving and suddenly starts limping again — especially if the lameness worsens over time — this may suggest that the implant is no longer functioning as intended.

Sometimes this lameness appears with stiffness, reluctance to move, or even complete disuse of the limb. These signs are particularly concerning when they appear weeks or even months after surgery, as they may indicate a late-stage failure or bone loosening around the implant.

Pain is another critical indicator. Pets may cry out when touched, avoid using the limb altogether, or appear generally depressed or lethargic. They may also become irritable or aggressive due to ongoing pain. In some cases, implant failure leads to local inflammation or infection. Swelling near the surgical site, heat, redness, or discharge can indicate an underlying issue such as a surgical site infection or a reaction to a loosening or broken implant. Some pets will constantly lick or bite at the area, showing you that something doesn’t feel right.

In rare cases, broken hardware may be visible or palpable under the skin, especially in thin or small patients. You might notice a sharp angle or abnormal bump, suggesting displacement of the bone or migration of screws or plates. Any visible deformity or crepitus (a grinding or clicking sound when moving the limb) warrants immediate veterinary attention.

It's also important to consider behavioral changes. Pets in chronic pain or discomfort may lose appetite, become withdrawn, or show changes in sleeping patterns. Owners familiar with their pet’s usual demeanor often notice these small differences first — and they are often more meaningful than physical signs alone.

Diagnosing implant failure typically involves a thorough physical examination followed by diagnostic imaging. Radiographs (X-rays) are the most common tool and can show whether screws have loosened, plates have shifted, or the bone around the implant is failing to heal properly. In some complex cases, advanced imaging such as CT scans may be necessary.

Not all cases of lameness or pain after surgery are due to implant failure. Sometimes soft tissue injuries, muscle atrophy, or unrelated orthopedic conditions can cause similar symptoms.

That’s why veterinary evaluation is critical. If implant failure is confirmed, the treatment will vary depending on the type and severity of the problem. Some implants can be removed once the bone has healed, while others may need to be replaced or repositioned.

Prompt recognition and treatment of implant failure are essential to preserve limb function and reduce the chance of long-term complications. As a pet owner, being observant and proactive can make all the difference in your pet’s recovery journey.

References:

1. Beever, L. J., & Oxley, B. (2021). Complications in Small Animal Orthopedic Surgery. Veterinary Clinics of North America: Small Animal Practice, 51(1), 157–177. https://doi.org/10.1016/j.cvsm.2020.09.010
   

2. Fitzpatrick, N., & Yeadon, R. (2009). Complications of limb salvage surgery. Veterinary Surgery, 38(6), 710–721. https://doi.org/10.1111/j.1532-950X.2009.00586.x

About the autor

Felipe Garofallo is a veterinarian in Brazil, specialized in orthopedic and neurosurgical care for dogs and cats.

He is also the founder of Ortho for Pets – Veterinary Orthopedics and Specialties.