The implantation of an artificial joint is an enormous improvement in the quality of life for many people. Hip and knee endoprostheses enable patients to be mobile and active again after years of pain. But despite all the progress in the endoprosthetics, there is a feared complication: the prosthesis loosening . It is particularly critical of a hip tep and knee-tep , since untreated loosening not only cause pain, but also increase the risk of serious complications. In this article you will learn everything about the causes, symptoms, diagnostic procedures and treatment options for loosening a prosthesis.

What is a prosthesis loosening?

A prosthesis loosening is when the artificial joint component loses its firm anchoring in the bone. This loosening can be mechanical or infectious nature. In contrast to the normal age -related changes in an implant, real relaxation always leads to a restriction of the function and usually also pain.

There are two main forms:

• Aseptic prosthesis loosening : without bacterial participation, mostly mechanically conditional.
• Septic prosthesis loosening : caused by bacterial infections.

Both forms require different diagnostic and therapeutic approaches.

Causes of a prosthesis loosening

Aseptic causes of loosening

The aseptic loosening is the most common form. The following factors play a role here:

• Abrover particles : wear and tear of polyethylene or metal releases the smallest particles that can trigger an inflammatory reaction in the bone. This leads to osteolysis (bone loss).
• False loads : Axis deviations, leg long differences or muscular dysbalances lead to an uneven strain on the implant.
• Material fatigue : Long -term mechanical stress can weaken the implants.
• Head -value bone quality : osteoporosis or bone necrosis affects the an implant anchoring.

Septic causes of a loosening

Septic loosening is a serious complication:

• Periphetic infections : bacteria (e.g. staphylococcus aureus, staphylococcus epidermidis) settle on the prosthesis surface and form a biofilm that is difficult to treat.
• Hematogenic scattering : infections such as tooth root infections or urinary tract infections can transport germs over the bloodstream to the joint.

Symptoms of a prosthesis loosening

A prosthesis loosening is not always obvious. Typical symptoms are:

• Exposure pain , often also rest pain
• Feeling instability in the affected joint
• Swelling and overheating
• Limited mobility
• Clicking or scraping noises when moving
• Fever (with septic loosening)
• Loss of strength in the leg

The symptoms can begin gradually and get stronger in the course.

Diagnostics: How is a prosthesis loosening determined?

The diagnosis of prosthesis loosening requires a combination of clinical examination and imaging as well as laboratory chemical procedures:

1. Clinical examination

• Assessment of gait, leg length, mobility, pain, effusions

2. Imaging techniques

• X -ray : Standard method for assessing loosening symbols such as folding or migrations
• CT : Detailed representation of bone structures and implant position
• Skeletal scintigraphy or PET-CT : Early detection of loosening through increased activity in bone metabolism

3. Laboratory tests

• Inflammation marker : CRP, blood steering speed (BSG)
• Blood cultures in septic suspicion

4. Joint puncture

• Analysis of articular fluid for germ determination

Why the skeletal scintigraphy can only reliably detect loosening after 1.5 years

The skeletal scintigraphy is considered sensitive, but not very specific in the diagnosis of prosthesis loosening. In the first 12 to 18 months after the operation, scintigraphy often shows a normal postoperatively increased metabolic activity in the area of ​​the prosthesis. However, this does not prove proof of loosening. Only if this activity remains beyond the expected time or has been re -developed can a pathological change be accepted. Therefore, the scintigraphy can only be interpreted in a postoperative manner at the earliest 1.5 years , since previous results are too often false-positive.

More information here:   skeletal pencil-in-the-diagnostics-der-prosthesis loosening

Therapy options for prosthesis loosening

Depending on the cause, the procedure differs significantly:

• Aseptic loosening : interchanging operation of the loosened components or the entire prosthesis.
• Septic loosening:
• Two -time procedure: removal of the prosthesis, antibiotic therapy and later new implantation.
• Rarely one: only in highly specialized centers and under certain conditions.

The choice of the new prosthesis depends on the bone situation. revision implants are often used.

Hip joint-loosening of a hip prosthesis (hip-tep)

Causes of loosening a hip tep

The following factors play a role in loosening a hip-TEP

• Abriting of polyethyleneinlays
• misalignment after primary implantation
• Age processes of the implant
• Primary infections or late infections

Symptoms in loosened hip prosthesis

Patients often complain about:

• Groin pain
• Stinging pain in the thigh
• Exposure pain when climbing stairs or getting up
• Gait uncertainty
• Shortened leg or changed leg axis

Diagnostics with loosening Hip-Tep

• X -rays (pelvic overview, axial beam movement)
• Bone scent
• Laboratory controls
• CT in complex cases
• Point for suspected infection

Therapy with loosening hip-tep

• Exchange of the loosened components (just a pan or only shaft)
• Change to modular shaft systems or revision pans
• Bone build -up using spongiosa plastic in defects
• Antibiotic therapy for septic cause

Special challenges

• Restoration of the leg length
• Reconstruction of the rotary centers
• Avoiding further loosening

Kniegelenk-Loosening of a knee prosthesis (knee-tep)

Causes of loosening a knee-tep

The loosening of a knee-tep can result from:

• Polyethylene wear and abrasion
• Loosening of the tibia shaft
• Axis misalignment (e.g. Valgus or Varusgonarthonthrosis)
• Band instability
• Infections

Symptoms with loosened knee prosthesis

Typical symptoms are:

• Stress -dependent pain
• Feelings of instability when walking
• Swelling, especially after stress
• Pours in the knee joint
• Movement restrictions
• Knack or knocking noises

Diagnostics with loosening knee-tep

• X -ray images under load
• Long-Leg view to assess the leg axis
• Bone scintigraphy or PET-CT
• Laboratory chemical tests for infection search
• Puncture if you suspect septic loosening

Therapy with loosening knee-tep

• Exchange of the tibial part, female judgment or both shares
• Use of modular revision prostheses with axle guidance
• Bone structure using a metal or bone augmentation
• Targeted antibiotic therapy for infection

Prevention: prevent prosthesis loosening

• Weight loss
• Regular dentist controls
• Avoidance of risk infections
• Gentle sports (swimming, cycling)
• Regular follow -up examinations

Forecast after revision surgery with loosening

The results according to revision interventions are very good in specialized centers:

• 80-90 % of the revision prostheses last at least 10 years.
• Mobility can be largely restored.

FAQ: Frequent questions about prosthesis loosening

How does a loosened hip tep feel?

• Often groin pain, feeling of instability and limited resilience.

How long does a knee-tep last?

• Modern knee prostheses last 15-20 years, sometimes longer.

Is every relaxation an emergency surgery?

• No, but a significant loosening should be treated quickly to avoid consequential damage.

Outlook: Rehabilitation, aftercare and prevention

Structured rehabilitation after revision surgery is crucial for the return to mobility. Enlightenment and planning should already be started preoperatively. Mobilization, physiotherapy and pain management are in the foreground during inpatient rehab. Afterwards, outpatient programs are recommended that specifically go into a gait, muscle strength and joint function.

Prevention of prosthesis loosening begins long before the first operation:

• Careful selection of the implant
• Correct positioning
• Treatment of risk factors (e.g. osteoporosis)
• Regular follow -up examinations
• Patient training for behavior in everyday life (e.g. fall prophylaxis, joint -gentle load)

Scientific studies and evidence situation

Numerous studies show the relevance and frequency of prosthesis loosening:

• A large register analysis by the endoprosthesis register Germany (EPRD) shows that about 5–10 % of all endoprostheses must be revised within 10 years based on a loosening.
• Studies on aseptic relaxation describe abrasion as the main cause-especially with polyethylene inlays of older generation.
• In septic loosening, a meta -analysis showed that the two -time revision process has a higher success rate compared to the one -time change (success rate> 90 %).
• Modern imaging methods such as the PET/CT with marked leukocytes are in the further development and offer improved sensitivity in unclear cases.

Influence factors according to the study situation:

• Smoking, diabetes mellitus and obesity increase the risk of loosening significantly.
• Men are slightly affected than women.
• Patients under the age of 60 with a higher level of activity have an increased risk of revision.

Conclusion: Early diagnosis of prosthesis loosening protects mobility

An early recognized prosthesis loosening can usually be treated successfully. If you take typical symptoms such as pain or instability seriously and seek medical help promptly, you protect your quality of life in the long term.

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