“The Knee Loosened Within a Few Years”: When a NexGen or Zimmer Knee Implant Fails

Medication, drug and device guides · 13 min read · Published 10 November 2026 · Reviewed 10 November 2026 · Next review May 2027

By Dr Rosemary Listing, PhD (Law) · Medical negligence lawyer since 2014 · Of Counsel, Peter Evans & Associates

If your knee replacement is failing, I want you to know that your questions are reasonable. You are entitled to know what was put in your body, and to proper investigation when it hurts. A failing knee is always worth having looked at.

This guide covers the TGA alerts, the signs of a failing knee, follow-up, records, and how the law looks at device and care claims.

Start with your question

• What were the Zimmer knee alerts?
• How do I know what knee I have?
• What is aseptic loosening?
• What are signs of a failing knee replacement?
• What does revision involve?
• Is it a device claim or a care claim?
• Could this be negligence?

Your knee replacement

A knee replacement resurfaces the ends of the thigh and shin bones, with a metal tray (the tibial component) fixed to the shin bone and a plastic insert as the bearing.

The TGA alerts

In 2014, a hazard alert covered the NexGen Complete Knee Solution MIS stemmed tibial component, because a manufacturing defect could stop a stem extension seating properly. Possible consequences included loosening, early revision and the insert not locking.¹ In 2015, a hazard alert covered the Persona Trabecular Metal tibial plate, because the complaint rate for loosening and radiolucent lines was higher than expected.² In both, surgeons were advised to continue normal follow-up.

Finding out what you have

Your hospital record should contain the implant stickers with brand, product and lot numbers. Ask the hospital or your surgeon for them.

Questions to ask

• What brand and model is my knee, and is any part subject to an alert?
• Do my X-rays show loosening?
• What are my options if it is loosening?
• Will you report this to the TGA?

Loosening

Loosening is one of the reasons a knee replacement may need revision, along with wear and infection.³ It often shows as gradually worsening pain, especially when standing or walking, and can be seen on X-rays over time.

Warning signs

Revision

Revision replaces loose parts and is usually a bigger operation, with risks including nerve and vessel damage, infection and ongoing pain.³ Our guide to questions before revision surgery can help.

Device or care?

There may be two sets of questions: whether the product was defective, which is a claim against the manufacturer or supplier, and whether your follow-up and investigation were adequate. Our guide to the Exactech knee recall explains a similar situation.

What to look for in the records

Your records are often where the story becomes clear. You have a right to access your own health information. In NSW the Health Records and Information Privacy Act 2002 covers both public and private providers, and the Information and Privacy Commission explains how to ask.⁴ Our step-by-step guide to getting your medical records in Australia walks you through it.

How the law looks at it

A knee implant that loosens is not automatically anyone’s fault. Implants can fail despite good surgery. The questions are whether the device was defective, whether the surgery was performed properly, and whether symptoms and X-ray changes were followed up.

A claim usually turns on three questions: whether the care fell below what peers would widely accept as competent practice (section 5O of the Civil Liability Act 2002 (NSW))⁵, whether that shortfall probably caused harm you wouldn't otherwise have had (Tabet v Gett)⁶, and, where it matters, whether you were told the material risks first (Rogers v Whitaker)⁷⁸. Our guide to how a medical negligence claim works explains each one in plain terms.

In a knee implant case, the questions might be: was the implant subject to an alert, and were you followed up? Was the component placed and fixed properly? When X-rays showed changes, were they acted on?

In plain terms, the question is whether earlier investigation or a non-defective implant would probably have avoided or reduced the harm, such as bone loss or a bigger revision.

For a knee replacement, that would usually include the risks of loosening and revision.

Who can claim, and when

The person with the knee replacement can claim. In NSW, time usually runs from when you knew, or ought to have known, enough to claim, not from the treatment itself, and courts can sometimes extend it, so an old injury may still count. See time limits in NSW or other states, and ask early.

More: complaint or claim? · how a claim is paid for · what a claim can cover

In my practice

In knee implant files, X-ray reports often mention a line or subtle change years before revision, and the follow-up letters say “keep an eye on it”. Reading the reports in order often shows the problem developing in plain sight.

Both things can be true

Your surgeon may have done careful surgery, and a device or follow-up may still have let you down. Both can be true.

The bigger picture

Device alerts are issued by the Therapeutic Goods Administration.¹ You can check a practitioner on the Ahpra public register,⁹ and complaints about care in NSW can go to the Health Care Complaints Commission.¹⁰ Our guide to getting your medical records explains how to ask for your file.

Support

You don't have to work through this alone. These services can help:

• Lifeline, 24-hour crisis support: 13 11 14 (listed on healthdirect's helplines page)¹¹
• Beyond Blue, anxiety and depression support: 1300 22 4636
• Medicare Mental Health, help finding mental health support: 1800 595 212
• healthdirect, 24-hour nurse advice: 1800 022 222
• Health Care Complaints Commission (NSW): 1800 043 159

A man who didn’t know his knee’s brand now knows its history. You deserve that too.

With care,
Rosemary

Frequently asked questions