Are you wondering about the post-operative process after knee replacement surgery? How long does physical therapy last? What is the importance of physical therapy after knee replacement?
As a physical therapist, I work with individuals almost every day who undergo knee surgery and receive a total or unicompartmental knee arthroplasty.
Most commonly, this is due to pain and arthritis, although it can occur in other contexts as well (fracture, illness).
Following the surgery, rehabilitation sessions are necessary. Rehabilitation is increasingly done at home and in clinics, and less commonly in rehabilitation centers, as post-operative recovery has become simpler.
Here are some answers to the main questions that patients have before and after a total or unicompartmental knee replacement surgery.
Enjoy your reading 🙂!
Last update: June 2023
Is a knee replacement considered a major operation?
In case of knee osteoarthritis (patellofemoral or femorotibial osteoarthritis) and especially significant pain and difficulty in performing daily activities (walking, stairs, sports), knee replacement may be necessary.
The surgery is performed only after the failure of other conservative treatments:
- Engaging in gentle and regular physical activity
- Physical therapy sessions
- Taking pain relievers
- Identifying and reducing or eliminating strenuous activities
- Weight loss
- Natural solutions for knee osteoarthritis, such as taking CBD for arthritis pain, etc.
A total or unicompartmental replacement may be implanted. Another name for this procedure is total or unicompartmental knee arthroplasty.
In France, individuals generally enter the hospital or clinic the day before the operation. The surgery typically lasts between 1 hour and 1 hour 30 minutes. Anesthesia can be general or regional (spinal anesthesia).
Individuals usually remain hospitalized for 3 to 5 days. In the United States, the typical length of hospital stay for a total knee replacement surgery without complications ranges from 1 to 3 days.
For a few days after the surgery, a Zimmer splint is sometimes prescribed by PT. Its purpose is to relieve pain and, most importantly, prevent the knee from unlocking. Indeed, the thigh muscle, the quadriceps, is somewhat impaired after the operation.
The knee can “give way” if too much pressure is applied. This usually lasts less than 3 days, and the Zimmer splint can then be put away.
A knee replacement is considered a major operation. The procedure requires anesthesia, a surgical incision, bone preparation, and the implantation of the prosthetic components. It typically requires hospitalization and a period of post-operative recovery and rehabilitation.
What is the best age for knee replacement surgery?
The question of the right age to undergo surgery often arises among individuals with knee osteoarthritis.
They often seek advice from their physical therapist, who can assist them with this issue or other health problems.
Two categories of individuals have even more questions regarding the benefits of knee replacement surgery based on their age:
- those under 30, 40, 50 or 55 years old,
- and those over 70 or 80 years old.
Before 40 years or 45 years
More and more people are undergoing knee replacement surgery before the age of 50. Several studies have evaluated the recovery and satisfaction of individuals in this age group (Aujla, 2017). Here are their results:
- Their scores on functional tests (ability to perform exercises and daily activities) increase by 50% after the surgery.
- Their range of motion improvement between before and after the surgery is 2.9 degrees (out of a total range of 110 to 140 degrees).
- 10 years after the surgery, 5.4% of knee replacement had to be revised.
- 85.5% of people who undergo total knee replacement before the age of 50 are satisfied or very satisfied with the surgery.
Why do some people experience knee arthritis and pain at such a young age? Often, there have been accidents and injuries to the knee. For example, a patellar fracture.
After 80 years
It has been observed that individuals who undergo knee replacement surgery after the age of 80 have a similar functional recovery as those operated on between the ages of 65 and 75. Their satisfaction with the surgery is also comparable (Kuperman, 2016).
However, the risks associated with anesthesia and rare complications of the surgery are greater in this age category.
Therefore, this situation needs to be evaluated on a case-by-case basis, taking into account the intensity of the discomfort caused by arthritis as well as the overall health status.
There is no specific ideal age for knee replacement. Several factors need to be considered and discussed with your doctor, physical therapist, and surgeon, including:
- Your pain level
- Functional limitations in daily activities and sports (Walking with knee osteoarthritis is not dangerous)
- Your overall health and weight
- Previous treatments you have tried
- Any knee-related problems or surgeries you have had
- And more.
Swollen knee and pain after knee replacement: is it normal?
After total or unicompartmental knee replacement surgery, it is entirely normal for the knee to swell. The circumference of the knee can increase by several centimeters compared to the other side, often by 5 to 6 centimeters.
The swelling (edema) can persist for at least 2 to 3 weeks. Sometimes, it can last several months without being a cause for concern.
Your physical therapist will monitor the gradual reduction of the swelling and, most importantly, ensure that it does not worsen.
Wearing Class 2 compression stockings (see on Amazon) can help limit the swelling during the time they are worn.
The knee may also feel warm in the first few days following the surgery, sometimes lasting for several weeks. This isolated symptom should not be a cause for worry. A warm knee can also appear red without being a cause for concern.
Postoperative pain is common. Initially, it is relieved by analgesic medications.
Generally, and in the absence of contraindications, opioids (morphine-like drugs) are administered in the first few days. Depending on the patient’s overall condition, anti-inflammatory drugs may also be prescribed.
Typically, in the first few days after the surgery, pain can be quickly controlled with only level I analgesics (such as acetaminophen/paracetamol), which are sometimes taken for several weeks.
Postoperative pain can also be relieved by:
- applying cold packs
- frequently changing the knee’s position (sometimes extended, sometimes flexed),
- adopting a comfortable sleeping position (especially with the use of pillows).
- Massage provides temporary pain relief at best but does not reduce edema or improve flexion or walking recovery.
Read my comprehensive blog post on pain after knee replacement surgery for more information.
Are there any restricted movements?
Great news! There are absolutely no restricted movements after a total or unicompartmental knee replacement. And this applies from the day after the surgery and throughout your life!
Sometimes, individuals who have undergone knee replacement surgery expect to have restricted movements because they or their loved ones have had a hip replacement, which does require avoiding certain movements.
Only pain should limit you in certain movements. Of course, in the first few days after the operation, your knee won’t bend and extend as well as before. But these movements themselves are not contraindicated; it’s only the pain that limits them.
Many people undergoing rehabilitation after a total knee replacement seek advice on precautions to take.
The main advice that can be given is to be as active as possible without causing or exacerbating pain.
Prolonged static standing (e.g., while doing dishes or cooking) is not recommended as it can exacerbate swelling. Similarly, avoid sitting all day with your knee flexed as it can cause your knee to stiffen. Move as much as possible.
Physical therapy after knee replacement surgery
Here is information about rehabilitation after total or unicompartmental knee replacement.
Starting as early as possible: Knee replacement rehab timeline
The earlier individuals who undergo knee replacement surgery start physical therapy, the faster and better their recovery, and the lower the risk of certain side effects (such as deep vein thrombosis in the lower limbs).
Another positive effect is that the overall cost of care related to the surgery, pre- and post-operative appointments, and follow-up care is lower for individuals who mobilize more quickly.
What is considered early rehabilitation? Starting rehabilitation within the first 2 weeks following knee replacement surgery. Late rehabilitation begins 2 weeks or more after the operation.
In France, it is very common for rehabilitation to begin the day after the surgery.
In a rehabilitation center, at home, in a clinic, or through teleconsultation?
Since the late 2000s, the French Health Authority no longer recommends rehabilitation center stays for normal progression total or unicompartimental knee replacements. However, some individuals still choose to stay at a rehabilitation center based on their social context, other health issues, or complications related to the surgery.
After the hospital stay, most people in France who undergo knee replacement surgery return home. Home-based physical therapy is often prescribed as individuals are unable to drive for at least 5 to 6 weeks. Subsequently, rehabilitation may be continued at a clinic.
Simple teleconsultations conducted by physical therapists can also be sufficient.
The reduction of pain and functional recovery are similar whether patients are seen at home or at a clinic. The recovery of joint range of motion is generally better for patients seen at home (Artz, 2015).
No special equipment is required for knee replacement rehabilitation, which allows for physical therapy sessions to be conducted at home.
How many times a week should I do physical therapy after knee replacement?
If the person who underwent the surgery does not have any specific health concerns and the surgery went well, they generally see a physical therapist daily during their stay at the hospital or clinic (for about 1 to 5 days), and then 2 to 3 times per week for a month.
The sessions are then spaced out.
It depends a lot on the anxiety of the person, and whether or not they want to take care of themselves.
For example, I sometimes had patients in rehabilitation 5 times a week for 6 weeks after a total knee replacement without complications. Then they continued twice a week in private practice.
On the other hand, I have rehabilitated some people who were only seen twice in the hospital. Then twice a week at home by me for 2 weeks. Then only once a week. Then once every 2 weeks. In all, they had only 8/10 physio sessions during their whole rehabilitation period after total knee replacement, but they did activity and exercises in autonomy every day.
What happens if you don’t do physical therapy after knee surgery?
If you have self-taught yourself about knee replacement rehabilitation, you may consider doing your own rehabilitation. Some individuals choose this option, but they are in the minority to my knowledge.
Most people prefer to be supervised at least to some extent by a professional with experience in this field. This is mainly for reassurance, to ask questions, and to ensure that things are progressing normally.
Are you considering not doing any rehabilitation at all? Neither on your own nor with a physical therapist? You are likely increasing your risk of experiencing complications due to this complete absence of rehabilitation, such as knee stiffness.
However, it depends on how you spend your days. If you are very active and fortunate enough to avoid complications, sometimes things can go well without rehabilitation. However, this is not what I recommend to my patients who ask for my opinion on this matter.
How Long Does Rehabilitation Last After Knee Replacement?
It is important to distinguish between the necessary rehabilitation time and the recovery time. I discuss this in more detail in my blog post on the recovery period after knee replacement (coming soon in english).
The necessary rehabilitation time is generally around 6 weeks after knee replacement surgery. Assessments conducted by physical therapists help determine when rehabilitation can be discontinued.
The absence or reduction of pain, recovery of knee flexion and extension range of motion, and restoration of previous functional abilities (walking without crutches, climbing stairs, cycling, etc.) indicate that rehabilitation is complete.
The recovery time is often longer. Swelling in the operated knee can persist for several months without causing concern. Some individuals may also take longer to regain their pre-surgery ability to climb up and down stairs or walk long distances.
On average, it takes 2 to 6 months to regain the level, intensity, and frequency of activities performed prior to knee replacement surgery (slightly less for unicompartimental knee replacements).
It is normal to require several months to recover from a knee replacement. Your knee replacement rehabilitation lasts for several weeks but will likely end before you have fully recovered.
Is the use of a continuous passive motion (Kinetec) helpful?
Continuous passive motion is an electric device used for knee mobilization. The presence of a caregiver is only necessary for the initial setup, after which the patient can manage the machine on their own using a remote control. Most hospitals, rehabilitation centers, and even some private physiotherapy clinics are equipped with this device.
Patients generally appreciate this device as it allows them to “work” on knee flexion and extension without having to do anything, comfortably seated. Even when the flexion is perfect, reaching 100 or even 110 degrees, some individuals may want to continue using the continuous passive motion machine.
But is it truly useful? Is it necessary? No. When comparing the recovery of individuals who have used the continuous passive motion therapy with those who have not, there is no difference between them three months after the surgery. And if we compare them at earlier stages, it is usually those who have not used the continuous passive motion who have better knee flexion recovery (although the difference is minimal, around 6 degrees).
Continuous passive motion device, also known as the Kinetec, is highly appreciated by patients, but it does not provide any additional benefits to the rehabilitation process. Whether you use it or not after knee replacement surgery, your recovery will be just as successful. Kinetec does not contribute to better or faster recovery.
Source: Mau-Moeller 2014
Risk of knee replacement surgery: Possible complications
What is more important to remember? The list of possible complications associated with knee replacement surgery and its aftermath, or the fact that these complications are relatively rare? The second piece of information, without a doubt.
For example, one of the possible complications is knee stiffness, where the knee remains locked at 75-90 degrees (compared to an average range of motion of 100-110 degrees after knee replacement, or 130-140 degrees without knee replacement or knee arthritis). However, this occurs in only 4 to 16% of patients.
Other potential complications include:
- deep vein thrombosis,
- knee algodystrophy,
- or delayed wound healing, among the more common ones (which still remain more of an exception than the norm).
The only clearly identified risk factor for developing complications after knee replacement surgery is having a body mass index (BMI) above 30 (obesity).
Running, golf, skiing after knee replacement?
There is no specific study that specifically examines the risk of returning to sports after knee replacement surgery. However, certain sports and activities are generally recommended after knee replacement, including:
- Walking (and potentially hiking)
- Stationary biking
Hiking is possible with both total and unicompartmental knee replacements.
Sports such as football or tennis are not formally discouraged but are not highly recommended either. Activities involving heavy lifting (weightlifting) or significant and repetitive impact (running, skiing) are strongly discouraged.
- Up to 88% of people resume their previous physical activity levels after knee replacement surgery.
- Approximately 70% continue to engage in sports activities 10 years after the surgery.
- However, this varies depending on the sport. For example, only 20% of tennis players resume playing after knee replacement surgery.
- 40% of individuals who could only walk for a maximum of 10 minutes before surgery are able to walk for over 60 minutes after knee replacement surgery. Their walking speed also increases. (Oljaca, 2018)
Sports can be gradually reintroduced once pain has subsided and the knee has regained adequate range of motion. This typically occurs 2 to 6 months after knee replacement surgery.
Here’s what I wanted to tell you about this! I wish you a very good recovery! Do you have any comments or questions? Your comments are welcome 🙂 !
If you feel the need to learn more about the recovery period after a knee replacement, I wrote this guide in eBook format:
You may also like:
- Swollen knee after knee replacement
- There are no limitations after knee replacement surgery!
- Pain after Knee Replacement
Hussain, S., Neilly, D., Baliga, S., Patil, S., & Meek, R. (2016). Knee osteoarthritis: a review of management options. Scottish Medical Journal, 61(1), 7–16. doi:10.1177/0036933015619588
Kuperman EF, Schweizer M, Joy P, Gu X, Fang MM. The effects of advanced age on primary total knee arthroplasty: a meta-analysis and systematic review. BMC Geriatr. 2016;16:41. Published 2016 Feb 10. doi:10.1186/s12877-016-0215-4
Total Knee Arthroplasty for Osteoarthritis in Patients Less Than Fifty-Five Years of Age: A Systematic Review. The Journal of Arthroplasty. Volume 32, Issue 8, August 2017, Pages 2598-2603.e1
Masaracchio M, Hanney WJ, Liu X, Kolber M, Kirker K. Timing of rehabilitation on length of stay and cost in patients with hip or knee joint arthroplasty: A systematic review with meta-analysis. PLoS One. 2017;12(6):e0178295. Published 2017 Jun 2. doi:10.1371/journal.pone.0178295
Rodríguez-Merchán EC. The stiff total knee arthroplasty: causes, treatment modalities and results. EFORT Open Rev. 2019;4(10):602–610. Published 2019 Oct 7. doi:10.1302/2058-5241.4.180105
Review article: Patient characteristics that act as risk factors for intraoperative complications in hip, knee, and shoulder arthroplasties. J Orthop. 2019 Jun 17;17:193-197. doi: 10.1016/j.jor.2019.06.022. eCollection 2020 Jan-Feb.
Rutherford, R. W., Jennings, J. M., & Dennis, D. A. (2017). Enhancing Recovery After Total Knee Arthroplasty. Orthopedic Clinics of North America, 48(4), 391–400.
Active physiotherapy interventions following total knee arthroplasty in the hospital and inpatient rehabilitation settings: a systematic review and meta-analysis.Physiotherapy. 2018 Mar;104(1):25-35. doi: 10.1016/j.physio.2017.01.002. ainsi que Artz N, Elvers KT, Lowe CM, Sackley C, Jepson P, Beswick AD. Effectiveness of physiotherapy exercise following total knee replacement: systematic review and meta-analysis. BMC Musculoskelet Disord. 2015;16:15. Published 2015 Feb 7. doi:10.1186/s12891-015-0469-6
Oljaca et al. Current knowledge in orthopaedic surgery on recommending sport activities after total hip and knee replacement. Acta Orthop Belg. 2018 Dec;84(4):415-422.
Mau-Moeller A, Behrens M, Finze S, Bruhn S, Bader R, Mittelmeier W. The effect of continuous passive motion and sling exercise training on clinical and functional outcomes following total knee arthroplasty: a randomized active-controlled clinical study. Health Qual Life Outcomes. 2014 May 9;12:68. doi: 10.1186/1477-7525-12-68. PMID: 24886619; PMCID: PMC4024275.
By Nelly Darbois
I love to write articles that are based on my experience as a physiotherapist and extensive research in the international scientific literature.
I live in the French Alps 🌞❄️ where I work as a physiotherapist and scientific editor for my own website, where you are.