Diagnosis: Knee Replacement Surgery

 In Exercise and Health

What is Knee Replacement Surgery?

A knee replacement (or knee arthroplasty) is a surgical procedure to replace the worn out, inflamed weight bearing surfaces of a damaged knee joint with artificial substitutes, called implants. The goal is to reduce pain and restore knee function so that patients can have increased participation in daily life and independence.

Knee Replacement Surgery

Total Knee Replacement (source: WikiMedia Commons)

Knee replacements can be partial or total. #performbetter @pogophysio Click To Tweet

Knee replacements can be partial or total. In a total knee replacement, a curved implant is secured to the distal end of the femur (thigh bone), a flat implant is secured to the proximal (upper) part of the tibia (shin bone) and a polyethylene insert is placed between the two implants to act as the meniscus, which absorbs shocks and distributes loads. Sometimes, the patella (kneecap) is also replaced.

Reasons for Knee Replacement Surgery

Knee and hip replacements are now amongst the most common of orthopedic surgeries, and the number continues to grow every year. The main reason for knee replacement surgery is to alleviate pain and stiffness due to arthritis, which limits a lot of activities such as walking and running.

Knee Replacement Surgery

Knee Arthritis (source: WikiMedia Commons)

With advanced arthritis, after a significant portion of cartilage has been worn away, the knee joint is left with bone rubbing against bone. This results in chronic inflammation, which causes chronic pain and swelling and thickening of joint capsule, which leads to joint stiffness. Chronic pain and stiffness are hallmarks of advanced arthritis.

Knee replacement is performed for advanced osteoarthritis, rheumatoid arthritis and psoriatic arthritis, after non-surgical conservative treatment methods have failed to reduce pain and restore function.

Surgical Outcomes and Risks

The main risk associated with knee replacement, or any surgery, is infection. Knee joint infection occurs in less than 1% of patients post-surgically. Your surgeon or nurse can help you with wound management to reduce the risk of infection.

Another major risk is deep vein thrombosis (blood clots). It is a complication from being under general anaesthetic and immobility and can affect up to 20% of patients. The hospital physio may give you exercises to reduce the risk of DVT.

Stability can also be an issue into the future, with the knee giving away (collapsing unpredictably). This is where physiotherapy can help.

Patients can expect average stay in hospital of 5 days after surgery, when their vital signs (e.g. blood pressure, heart rate) return to a normal range and they can confidently walk prior to discharge.

Physiotherapy for Total Knee Replacement

Physiotherapy post knee replacement surgery aims to reduce pain, increase knee range of motion, prevent prosthesis failure and help the patient return to function.

Physiotherapy normally begins immediately after surgery where patients are prescribed exercises to prevent the weakening of the muscles around the knee. The exercises progress until patients can achieve adequate knee flexion, weight bear and walk for short distances before discharge.

A review of studies by (Artz et al., 2015) shows there is evidence that physiotherapy can be beneficial for patients in the short term.

There are 4 stages to full recovery:

  • Mobilisation – increase range of motion
  • Static strength – increase the strength of muscles that stabilise the knee, especially the VMO muscle
  • Dynamic strength – increase quadriceps, hamstrings and calf muscles through entire range
  • Stabilisation – increase stabiliser muscle strength to prevent dislocation and collapse and to help the patient achieve a good pattern of walking

Wayne Wu
Student Physiotherapist


Artz, N., Elvers, K. T., Lowe, C. M., Sackley, C., Jepson, P., & Beswick, A. D. (2015). Effectiveness of physiotherapy exercise following total knee replacement: systematic review and meta-analysis. BMC Musculoskeletal Disorders, 16(1), 15. doi: 10.1186/s12891-015-0469-6

Verspecht, L., Wright, L., & Van Melkebeke, K. (2016). Total knee arthroplasty  Retrieved December 05, 2016, from http://www.physio-pedia.com/Total_knee_arthroplasty

Wikipedia contributors. (2016, November 28, 2016). Knee replacement  Retrieved December 05, 2016, from https://en.wikipedia.org/w/index.php?title=Knee_replacement&oldid=751951964

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