How long does a partial knee replacement last, and what can go wrong?

How long they usually last

Large joint registries show that most partial knee replacements are still functioning many years after surgery, and a large number last well beyond ten years. On average, though, the chance of needing a second operation over the long term is higher than with a total knee replacement. Results depend heavily on choosing the right patient and placing the implant accurately, which is why careful assessment before surgery matters so much.

Why some partial replacements need revision

• Arthritis developing in another compartment of the knee
• Loosening of the implant from the bone
• Wear of the plastic bearing over time
• Dislocation of the bearing, in mobile-bearing designs, which is uncommon
• Unexplained persistent pain
• Infection, which is rare

When revision is needed, it usually means converting to a total knee replacement. This is generally more straightforward than revising a total knee, but it is still a bigger operation than the first one.

General risks of the operation

As with any joint replacement, risks include infection, blood clots in the leg or lungs, wound problems, stiffness, bleeding, injury to nearby nerves or vessels, and fracture around the implant. These are generally less frequent after a partial than after a total replacement. Your individual risk depends on factors such as diabetes, weight, smoking and heart or lung health, and Dr. Gelber will go through them with you before you decide.

Signs to have the knee checked

Arrange a review if, months or years after surgery, you notice new pain on the opposite side of the knee, increasing swelling, a feeling of instability or clunking, or pain that wakes you at night. Seek urgent care for a hot, red, very painful knee or a fever, as infection needs prompt treatment. Regular follow-up X-rays help spot loosening or wear early.