Prosthesis loosening is when an implant inside the body, such as an artificial hip or knee joint, loses its firm hold. The connection between the implant and the surrounding bone becomes weaker, so the prosthesis no longer sits securely.
How does prosthesis loosening happen?
After an artificial joint is put in, the bone normally grows firmly onto the prosthesis or is fixed in place with a special cement. Over time, however, this connection can become weaker. There are several reasons for this. Often it comes down to ordinary wear and tear. Every movement puts pressure and strain on the implant. This can cause tiny particles to break away from the prosthesis material or from the bone. Sometimes the body reacts to these particles with inflammation, which then causes the bone to break down.
Infections, repeated overloading, or an unfavourable position of the prosthesis can also contribute to loosening. In rare cases, the bone is simply not strong enough from the start to hold the implant long term.
What are the signs of prosthesis loosening?
Typical signs include pain around the artificial joint, especially when putting weight on it. At first, these symptoms are often mild or may be mistaken for muscle soreness. As time goes on, the affected joint may feel unstable. Some people describe a feeling that "something is no longer sitting right". Movement may become restricted, and sometimes a clicking or grinding sensation can be felt. In rare cases, swelling or warmth occurs, particularly if inflammation is involved.
The symptoms are not always clear-cut. Especially in older people or those who move around very little, loosening can go unnoticed for a long time. It is often only when pain increases or walking becomes difficult that the cause is looked into more carefully.
Should prosthesis loosening cause concern?
A diagnosis of a loose prosthesis unsettles many people. Questions arise: Is it dangerous? Does the prosthesis need to be removed straight away? What happens if nothing is done? In general, loosening is not an emergency, but it should be taken seriously. If the problem is ignored, the situation can get worse. Pain increases, mobility decreases, and the risk of falls goes up. In rare cases, severe loosening can lead to a bone fracture or infection.
Loosening usually develops gradually. This means there is time to discuss the next steps with the treating specialist. Many people worry that another operation is unavoidable. However, not every case of loosening requires immediate surgery.
What treatment options are available?
Treatment depends on how severe the loosening is, how troublesome the symptoms are, and what the main causes appear to be. With mild symptoms and only minimal loosening, a wait-and-see approach with regular check-ups may be taken first. Rest, targeted physiotherapy, and pain relief often help to stabilise the situation.
If pain increases or the prosthesis is very loose, a replacement of the implant is usually recommended. The loose prosthesis is removed and replaced with a new one, sometimes with additional bone reinforcement. If an infection is the cause, this must be treated first. This can mean the prosthesis is temporarily removed and a course of antibiotic treatment is carried out.
While this procedure is more involved than the original operation, modern techniques usually allow good restoration of movement. Most people are able to walk without pain again after a revision operation and can take part in everyday life.
What can be done to prevent loosening?
Some factors can be influenced to reduce the risk of loosening. Regular movement strengthens the muscles and takes pressure off the artificial joint. Excessive strain, such as jumping or contact sports, should be avoided. Keeping a healthy body weight also reduces the load on the prosthesis. It is also important to treat infections promptly so that bacteria cannot settle on the prosthesis.
Regular follow-up appointments with an orthopaedic specialist help to spot changes early. This means many problems can be treated at an early stage, before they develop into more serious complaints.
How is the diagnosis made?
If loosening is suspected, a thorough physical examination is usually carried out first. X-rays often show whether the prosthesis has shifted or whether the bone has broken down. In some cases, further imaging such as a CT scan or a bone scintigraphy is needed to assess the situation more precisely. Blood tests can provide signs of inflammation.
With this information, it is possible to establish how severe the loosening is and which treatment seems most appropriate. A detailed conversation with the treating specialist helps to plan the next steps together.
