Total Knee Replacement
Knee osteoarthritis is a common condition that can be managed effectively with conservative medical intervention and physical therapy. When osteoarthritis reaches its end stage, which is characterized by severe pain and poor functional status, conservative management may no longer be effective.1 In cases of end-stage arthritis, total knee replacement is often regarded as a highly beneficial treatment to alleviate pain and improve function.2
Are Knee Replacements Common? 3
In 2009, the number of people undergoing total knee replacement surgery in the United States was estimated to be 620,00. More than 97% of these procedures were the result of a diagnosis of knee osteoarthritis. It has been estimated that 4,007,400 adults over the age of 50 were currently living with a knee replacement in the US in 2013. Of those, 1,505,900 were male and 2,501,500 female.
The lifetime risk of a knee replacement for a 25-year-old adult is:
- 8.3% for men
- 11.5% for women
Pain & Function after Total Knee Replacement
Pain and physical function are expected to improve substantially in around 90% of people who receive a knee replacement.2 The most significant improvement takes place in the first three months after surgery; improvement often continues from three to six months, but more slowly.1,5 After six months more subtle improvements in pain and function may continue for a year or more.4
The following graph illustrates the progression of function and reduced pain that can generally be expected after a total knee replacement. An important point to note is that function declines immediately after surgery and starts to rebound at four weeks.
Physical Therapy after Total Knee Replacement
Initial Post-operative Physical Therapy
The goal of physical therapy immediately after surgery is typically to gain range of motion in the knee, leg strength, and enough functional independence to return home. Physical therapy usually begins in the hospital within 24 hours of the surgery.
When an individual returns home from the hospital or a rehabilitation center, a physical therapist may come to the patient’s house. Home-care physical therapy focuses typically on increasing walking quality and distance walked. Stair climbing, strength, and flexibility are also frequently addressed in home-care therapy.
Outpatient Physical Therapy Treatment
Once the individual has gained enough function to get back into the community, outpatient physical therapy begins. Physical therapy will often address deficits the therapist and patient agree upon. These deficits are usually related to:
- Poor max strength, power, and endurance strength (e.g., difficulty getting out of a chair or going down steps)
- A decrease in range of motion (e.g., difficultly bending the knee)
- Tight muscles (e.g., straightening the knee is difficult when walking)
- Balance & coordination (e.g., feels unsteady walking)
- Aerobic capacity (e.g., tires easily during activity)
These deficits are often improved through exercise, manual therapy (e.g., therapist moves the knee), and electrical stimulation of the thigh muscles.6 Ice packs and heat may be recommended, as needed.
Outpatient physical therapy will often last four to eight weeks. It is important to realize this is not the end of the rehabilitation process. It is often beneficial to continue with prescribed exercise for at least a year following surgery.