Knee Replacement
In advanced knee arthritis, the worn joint surfaces are replaced with metal and medical-grade plastic parts. The aim is to relieve pain and restore comfortable walking.
Knee pain is one of the complaints that limits daily life the most as we get older. Climbing stairs, going for a walk or even sleeping through the night can become difficult. When medication, exercise, weight control and injections are no longer enough, knee replacement is a well-established treatment to relieve pain and restore movement.
What is knee replacement?
In knee replacement, the worn and damaged joint surfaces are removed and replaced with parts made of metal and medical-grade plastic. The ends of the thigh bone (femur) and shin bone (tibia) are resurfaced, and a plastic insert is placed between them so the joint can glide. When needed, the back of the kneecap is resurfaced as well.
When the damage is limited to one part of the knee, a partial (unicompartmental) knee replacement may be suitable. When the damage is widespread, a total knee replacement is preferred. The choice is made after examination and imaging.
Who needs a knee replacement?
Knee replacement is most often performed for advanced osteoarthritis. Inflammatory joint diseases such as rheumatoid arthritis, joint damage after old fractures and some deformities may also require it. It is usually considered when:
- Pain clearly limits walking distance and everyday activities
- There is pain at rest or at night
- Medication, physiotherapy, weight loss and injections no longer give enough relief
- X-rays show marked narrowing of the joint space and damaged bone surfaces
- A bow-legged or knock-kneed deformity is getting worse
The decision is never based on the X-ray alone. How much the symptoms affect your life, your general health and your expectations are weighed together.
Preparing for surgery
Blood tests and a heart and lung assessment are done before surgery. Your medicines, especially blood thinners, are reviewed. Any infection of the teeth, urinary tract or skin is treated first, because infections elsewhere in the body are a risk for the new joint. Exercises taught before the operation make recovery easier afterwards.
How is knee replacement surgery performed?
The operation is usually done under spinal or epidural anaesthesia, which numbs the lower body, and sometimes under general anaesthesia. It generally takes 1-2 hours. The joint is reached through an incision at the front of the knee, and the damaged cartilage and bone surfaces are shaped precisely with dedicated instruments. The alignment of the leg and the balance of the ligaments are adjusted before the implants are fitted. The goal is a knee that is stable both straight and bent.
Recovery and rehabilitation
Most patients stand up with a walker the day after surgery and walk short distances. The hospital stay is usually a few days. In the first weeks, the aims are to control pain, reduce swelling and regain full straightening and bending of the knee.
- First 2 weeks: Walking with a walker or crutches, daily exercises, wound care
- Weeks 3-6: Walking with less support, stair practice, muscle strengthening
- Weeks 6-12: Return to most daily activities, driving (with your surgeon’s approval)
- Months 3-6: Strength and endurance largely return
Regular physiotherapy directly affects the quality of the result. It can take up to a year for the knee to feel fully natural.
Possible risks
As with any operation, knee replacement carries risks such as infection, blood clots in the leg veins, wound healing problems, stiffness and, in the long term, loosening of the implant. Many of these risks can be reduced with careful preparation, clot prevention, early movement and regular follow-up. The risks are discussed in detail, in relation to your own health, before surgery.
Frequently asked questions
How long does a knee replacement last?
Most modern implants work well for many years. Body weight, activity level, bone quality and regular check-ups all affect how long an implant lasts. Follow-up visits help detect any wear early.
When can I walk after surgery?
Most patients start walking with support the day after surgery. Walking without support usually becomes possible within a few weeks, although this varies from person to person.
Can both knees be replaced at the same time?
Some patients in good general health can have both knees replaced in one session. In most cases, however, the operations are planned a few weeks or months apart. The decision depends on heart and lung health and on rehabilitation arrangements.
Can I do sport with a knee replacement?
Low-impact activities such as walking, swimming, cycling and light gym work are encouraged. Running, jumping and contact sports are usually not recommended because they can wear the implant faster.
The information on this page is general and does not replace an examination. An examination is needed to decide which treatment suits you.