We are often asked about running after a knee replacement. People are mostly concerned about two things: “Will I be able to run after a knee replacement?” and “Will I wear out my knee replacement if I run?” This article distils what the latest research tells us (and doesn’t tell us). It also has some advice on how to increase your chances of running after having your knee replaced. Remember, if you need more help with an injury, you're welcome to consult one of our physios online via video call.
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In this article:
What does a knee replacement involve?
A knee replacement, also called a knee arthroplasty, is a surgical procedure to resurface the weight bearing surfaces of a knee joint damaged by osteoarthritis. A surgeon caps the ends of the thigh bone and the shin bone, which form the knee joint, and sometimes also the kneecap, with metal or plastic parts.
A partial knee replacement, also known as a unicondylar knee replacement, is when only one part of the knee joint is resurfaced.
What does the research say about running after a knee replacement?
Will I be able to run after a knee replacement?
Yes, there are people who go back to running and appear to do so without any issues.
A study of ultra marathon runners who took part in at least one of the five Ultra-Trail du Mont Blanc races in France from 2015 to 2017 (ranging from 55 km to 300 km) found that three of the four runners who ran with a knee replacement completed their race. This drop-out rate of 25% (admittedly from a tiny sample) compares favourably with the overall drop-out rate of 19.6% among the 3,171 surveyed runners who started a race.
None of the four runners with a knee replacement reported adverse symptoms relating to the knee before, during, or after the race, whereas some of the runners who had had hip replacements did report such symptoms.
Marco Konings and colleagues did a review of 19 research studies on a total of 4,074 knee replacement patients. They found that 23 out of a total of 131 runners in these studies had returned to running post-op.
The above shows that it is possible to run after a knee replacement, for ultra runners and for mere mortals.
However, in practice, not all runners who have had a knee replacement do go back to running, as is clear from the results of the Konings study. Several studies have found that the percentage of people who return to high-impact activities, such as running, after a knee replacement was much lower than that of people returning to lower-impact activities, such as cycling or swimming.
It is not clear from any of these studies whether people who didn’t return to running were physically unable to run after their knee replacement and/or whether they were afraid of damaging or wearing out their new knee. This brings us to the next question.
Will running wear out my knee replacement?
We’re not sure. Expert opinion is that high-impact activities may wear out your replaced joint more quickly, but there is actually no strong research to back this up. There’s very little research that investigated the effect of physical activity on prosthesis wear.
Mixed research results for general activity
In a 2021 overview of research on patients with replaced knees, Martin Thaler and colleagues found conflicting results. Some studies showed that active people with replaced knees were more prone to needing their replaced knee replaced once again than inactive people, whereas other studies found that people who were inactive post-op were more likely to need a second new knee. They concluded that there is currently conflicting evidence with regards to the effect of general physical activity on the wear and tear of a replaced knee.
We should keep in mind that the benefits of an active lifestyle for your general health (heart, preventing diabetes, improved bone density, etc.) may outweigh the risk that it poses to a replaced knee.
What about high-intensity exercise?
In a similar review of the research, Elena Zaballa and colleagues found only one paper that assessed post-operative “leisure time physical activity” (i.e. also sport) in relation to the risk of damage to your replaced knee. It showed no increased risk in participants doing "high-intensity" leisure activities. Unfortunately, they didn’t specify whether these high-intensity activities were "high-impact", such as running, or low-impact, e.g. interval cycling.
So, these results can’t produce a definitive answer. All it tells us is that you can likely do high-intensity exercise without increasing your risk of having to go for knee surgery once again but not what type of exercise is best.
What about high-impact activities (like running)?
We could not find any studies with empirical findings about the risk of damaging a replaced knee by running or doing other high-impact activities.
A research review conducted earlier this year on hip replacements showed that the degree of wear and tear depended not only on the amount of physical activity but also on the mechanical loading of the joint. This in turn depended on body weight, type of physical activity, and technique (whether you are an experienced or a newbie athlete), where high-impact activity and poor motor control increased the risk.
These results suggest that high-impact activities may increase the risk of damaging a hip replacement, but it was one of many factors. Research for knee replacements is still lacking.
A recent survey of knee replacement experts showed that the majority say that patients can safely go back to jogging and running after knee replacements. Thaler et al. questioned 120 knee surgeons from 31 countries, and 68% agreed that patients could go back to jogging after six months, 60% said they could jog on the road, 54% said that patients could run on a treadmill, and 51% said any type of running.
They didn’t explain how they defined the difference between jogging and running, but I assume jogging would be easy running and running would be harder sessions.
For some context, these experts agreed overwhelmingly that people who have had a knee replaced should never play squash again.
What’s the verdict?
A lack of research showing that running will wear out or damage your knee replacement should not be seen as evidence that running with a replaced knee is safe. It might increase your risk, but most experts these days feel that patients can resume jogging and running after six months.
How to increase your chances or running after a knee replacement
So, what can runners do to increase their chances of being able to hit the road or trails again after their knee replacement?
Start before your surgery
The research shows that knee replacement patients who stayed active until they had their surgery were more likely to return to their sport.
Staying active means that your general health is better and that your legs have better blood supply. This will help your knee to heal more easily. Your muscles will also be stronger, so you will regain your strength more quickly.
Yes, you may not be able to run soon after surgery, but try and find something you can do to stay active in the meantime. How about cycling, or swimming, or some gentle strength training? If you’re struggling to find something appropriate, a physiotherapist can help you to figure it out.
Don’t rush back into running
The majority of knee surgeons advise that it is only safe to start jogging or running after six months. This is because the body takes a long time to heal. It’s not just about getting your muscles strong. The bone where the new knee surfaces were attached requires time to settle and stabilise as well.
Build your base strength (and maintain it)
The stronger your muscles are, the more shock they will absorb, and the less strain your new knee will have to deal with. I find the leg press to be a very good all-round strengthening exercise for knees, especially since it can be adapted for individual circumstances.
The body works as a kinetic chain. It requires all the links to be strong and to take their share of the load.
Make sure you maintain your strength once you resume running by doing regular strength training sessions.
Balance and control
As mentioned earlier, poor motor control has been implicated as a factor that may increase the wear on your new knee. Motor control refers to how well-coordinated your body moves. For runners, this also impacts their running form.
You can retrain your motor control through exercises that challenge your balance. You should also focus on having good form when you do your regular strength training exercises, e.g. keeping your knees well aligned when you do squats. A good example of an exercise that develops strength and motor control is a single leg deadlift.
Less is often more
Many of my older patients who run find that they run better and get fewer injuries if they focus on doing only a few high-quality runs per week. They then top up their training week with lower-impact cross training sessions.
Everyone is different, but you will likely find that there is an upper limit of running volume that your knee can cope with. This can be frustrating, but trying to force it to do more might just lead to trouble and even cut your running days short.
Minimise the load on your new knee
Minimise the load on your replaced knee when you run. Things that might help include:
Cushioned running shoes - Hoka is a brand that provides good cushioning plus stability.
Running on soft surfaces
Working on good running form and not pushing into full exhaustion
Keeping your body weight within a healthy range. But remember that restricting your calorie intake too severely can have a negative effect on your bone health, so don’t overdo a weight loss diet.
Continuing your strength training and motor control exercises even after you go back to running.
Alternatives to running after a knee replacement
You should aim to incorporate a mix of activities into your week.
Aerobic exercise promotes health in general. It keeps your heart and lungs healthy and helps to treat and prevent diseases like diabetes.
If your knee won’t tolerate running or you want to switch to doing lower-impact activities anyway, you may find walking, incline walking on a treadmill, cycling, using the cross trainer, or swimming useful.
The World Health Organization (WHO) recommends that we do 150–300 minutes of moderate or at least 75–150 minutes of vigorous aerobic physical activity, or an equivalent combination of moderate and vigorous activity per week.
Strength and balance
Regular strength training at the gym can work, but your physio can also suggest exercises that you can do at home. Pilates, Thai Chi, and yoga are examples of activities that tick this box. The WHO currently recommends that people above the age of 65 incorporate three or more such sessions into their week.
How we can help
Need more help with your injury? You’re welcome to consult one of the team at SIP online via video call for an assessment of your injury and a tailored treatment plan.
We're all UK Chartered Physiotherapists with Master’s Degrees related to Sports & Exercise Medicine. But at Sports Injury Physio we don't just value qualifications; all of us also have a wealth of experience working with athletes across a broad variety of sports, ranging from recreationally active people to professional athletes. You can meet the team here.
About the Author
Rochoy, M., et al. (2020). "Does hip or knee joint replacement decrease chances to complete an ultra-trail race? Study in participants at the Ultra-Trail du Mont Blanc®." Orthopaedics & Traumatology: Surgery & Research 106(8): 1539-1544
Konings, M. J., et al. (2020). "Effect of knee arthroplasty on sports participation and activity levels: a systematic review and meta-analysis." BMJ Open Sport & Exercise Medicine 6(1): e000729-e000729
Thaler, M., et al. (2021). "Twenty-one sports activities are recommended by the European Knee Associates (EKA) six months after total knee arthroplasty." Knee Surgery, Sports Traumatology, Arthroscopy 29(3): 694-709
Mooiweer, Y., et al. (2022). "Being active with a total hip or knee prosthesis: a systematic review into physical activity and sports recommendations and interventions to improve physical activity behavior." European Review of Aging and Physical Activity 19(1): 1-16
Ponzio DY, Chiu Y-F, Salvatore A, et al. (2018) "An analysis of the influence of physical activity level on total knee arthroplasty expectations, satisfaction, and outcomes: increased revision in active patients at five to ten years." J Bone Joint Surg Am 100:1539–1548