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What is a knee replacement
In a knee replacement, the worn joint surfaces of the thigh bone and shinbone are replaced with metal components and a polyethylene insert. It is the main treatment for severe knee osteoarthritis when little cartilage remains.
The operation is well studied and markedly reduces pain in most patients. But it is major surgery with months of rehabilitation, so the decision is based on imaging, pain and limitations together, not on the X-ray alone.
We often receive the question “do I need a knee replacement?”, and just as often “can I postpone it?”. A clinic physician answers both after reviewing the images.
At a glance
- ICD-10: M17 — knee osteoarthritis, Z96.65 — presence of a knee implant
- Main indication: stage IV osteoarthritis with constant pain
- Hospital stay: 5–8 days
- Rehabilitation: 3 weeks, then outpatient
- Implant lifespan: about 82% last 25 years
- Cost in Germany: roughly €12,000–20,000
Signs you need a knee replacement
- Knee pain is constant, disturbs sleep and limits walking to 300–500 metres.
- The X-ray shows marked joint-space narrowing, bone spurs and deformity (stage III–IV osteoarthritis).
- Exercise, weight loss, painkillers and injections have not helped for 3–6 months.
- The limitations affect work and daily life, and you are ready for rehabilitation.
In a Danish randomised trial (NEJM, 2015), patients with severe osteoarthritis who had a knee replacement plus rehabilitation had more pain relief than those with rehabilitation alone. But serious complications were more frequent after surgery, and about three in four patients in the non-surgical group did not need a replacement within a year. That is why full conservative treatment should come first.
Total or partial knee replacement
| Total (TKR) | Partial (unicompartmental) | |
|---|---|---|
| When | Osteoarthritis in all compartments, deformity | Osteoarthritis in the inner or outer compartment only, ligaments intact |
| Advantages | Reliable long-term result | Smaller incision, faster recovery, feels more natural |
| Disadvantages | Longer rehabilitation | Revision surgery is needed more often |
| Lifespan (Lancet, 2019) | about 82% at 25 years | about 70% at 25 years |
The surgeon chooses the implant type based on standing X-rays, MRI and examination.
Recovery after knee replacement
| Stage | Usual timing |
|---|---|
| Standing with a walker | on the day of surgery or the next day |
| Hospital discharge | after 5–8 days |
| Rehabilitation centre | about 3 weeks |
| Walking without crutches | after 4–6 weeks |
| Driving, desk work | after 6–8 weeks |
| Final result | 6–12 months |
Why can there be so much pain after knee replacement? In the first weeks it is a normal tissue reaction. However, according to a systematic review in BMJ Open, 10–34% of patients report unfavourable pain a year or more later. Causes vary: inflammation, instability, component malposition, infection, and sometimes the pain comes from the spine or hip. Such pain should be investigated, not endured. More on rehabilitation in Germany.
How much does knee replacement cost in Germany
For self-paying patients, surgery with the implant and the hospital stay costs roughly €12,000–20,000. Rehabilitation (about €3,000–5,000 for 3 weeks), preliminary tests, accommodation for a companion and interpreting are paid separately. The clinic prepares an exact quote after reviewing the images.
Prices for regenerative treatment, which at earlier stages sometimes allows surgery to be postponed, are on treatment cost.
Prices are approximate. Each clinic sets its own conditions and price: we send your request to several clinics and forward their offers so you can compare.
Alternatives to knee replacement
Conservative treatment
Weight loss, thigh-muscle exercise, painkillers. This is the basis at every stage and a required step before surgery.
Injections
Cortisone briefly calms inflammation; hyaluronic acid and PRP can reduce pain for months in stage I–III osteoarthritis.
Corrective osteotomy
For leg-axis deformity in active people, it offloads the worn compartment and can postpone a replacement.
Radiofrequency ablation of the knee nerves (see injections and radiofrequency ablation) is an option when surgery is not possible. Regenerative methods do not grow new cartilage and are of little use at stage IV; an honest comparison is on regenerative treatment or knee replacement.
Contraindications and surgical risks
Surgery is postponed
Active infection (including skin, teeth, urinary tract), uncontrolled heart or lung disease, severe uncontrolled diabetes, a recent corticosteroid injection into the knee.
Possible risks
Thrombosis and embolism, implant infection (about 1%), stiffness, persistent pain, loosening or wear of components requiring revision.
See a doctor urgently after surgery
Fever, redness or discharge from the wound, sudden calf swelling and pain, shortness of breath — these need immediate examination.
Scientific evidence
Key studies on the effect, lifespan and pain after knee replacement:
- Skou ST et al. A randomized, controlled trial of total knee replacement. N Engl J Med, 2015.
- Evans JT et al. How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet, 2019.
- Beswick AD et al. What proportion of patients report long-term pain after total hip or knee replacement for osteoarthritis? A systematic review of prospective studies in unselected patients. BMJ Open, 2012.
Frequently asked questions about knee replacement
Do you need a knee replacement? Free second opinion
Send your knee X-ray or MRI and describe how long and where it hurts. The coordinator replies within 24 hours; a clinic physician gives an opinion in 1–3 business days.
Send images