Part of Hip osteoarthritis
Can hip arthritis cause knee pain, and can it cause back pain?
Warning signs, and when to get help
Can hip arthritis cause knee pain?
Yes, and it is the referral that costs people the most time. The knee gets the attention, the scan and occasionally the operation, while the joint doing the talking sits a hand's length higher up.
How often that happens is not a question anyone has answered properly for the general population, and the figures circulating online do not trace back to a study that measured it. The studies that do exist still tell you something. Among 60 people waiting for a primary hip replacement, 47 percent reported pain below the knee, in a study whose point was that 88.5 percent of the orthopedic trainees surveyed believed hip pain does not reach that far (Khan and colleagues, 2004). A team at a US arthroplasty center then published 21 cases of people being treated for knee pain whose source was the hip. Of those 21, 12 had already had surgical treatment on the knee with minimal or no relief, and 14 had complete resolution of knee pain after the hip was replaced (Dibra and colleagues, 2017).
Both of those describe people whose hip arthritis was advanced enough to reach a surgeon, not people in the first year of a grumbling hip. Neither gives you a percentage you can apply to yourself. What they establish is that the pattern is real, that it reaches below the knee, and that experienced clinicians miss it, which is reason enough to check.
For where hip joint pain sits in general, including the groin and buttock, see where hip arthritis pain is felt. This page is about what to do when the pain has turned up somewhere other than the hip.
Why does a hip problem show up in the knee?
Referred pain is the first of two mechanisms, and the two feel different. The hip joint is deep, and deep structures are poorly mapped in the brain compared with skin. The signal arrives and gets reported across a whole region of the limb, most consistently the groin and the front of the thigh, and often as far as the knee. Khan and colleagues argued from their data that the pain in their patients was referred from the hip rather than coming from the spine, which is the comparison their study was built around. Referred pain of this kind is not tender to press, does not swell, and comes and goes with what the hip is doing, not with what the knee is doing.
The other is mechanical, and it is the part that gets left out. A hip that has lost its turn and its extension changes the job description of everything below it. The step on that side shortens, the foot turns out a little, the pelvis rotates instead of the hip, and the knee ends up absorbing load in positions it was not doing before. That is clinical reasoning and practice observation rather than trial evidence: it is how physios explain what they see, not something a study on this page has measured. That version usually aches on the front or outer side of the knee, builds over a day on your feet, and settles overnight.
Both can be running at once in the same leg, so an assessment beats a guess.
How do you tell whether knee pain is coming from the hip?
Go all round the knee with your fingers: the inner joint line, the outer joint line, below the kneecap, behind it. Knee problems are usually tender somewhere, and pain referred from the hip usually is not.
Then sit down, cross the ankle of the sore leg over the other knee, let it rest there, and afterward stand and turn the whole leg inward from the hip. If either of those is stiff, blocked or produces your knee pain, the hip is the joint to have examined, and lost inward turn is often the earliest change physios find in one.
Swelling, locking, catching and giving way belong to the knee itself and point to structures inside it, so ask what the knee does and not just where it hurts: knee osteoarthritis covers the commonest of those.
Hip trouble shows up getting into a low seat and swinging the leg round, and on the first few steps after sitting. Knee trouble shows up going down stairs and standing up from a squat.
A shorter step, a sway toward one side or a sock you now struggle to reach all say hip, and hip pain when walking goes through what changes and what helps. None of these checks diagnoses anything. What they do is make an appointment faster.
Can hip arthritis cause lower back pain or sciatica?
There is no doubt that hip arthritis and lower back trouble turn up in the same person often. They affect the same age group, a stiff hip gives the lower back more rotation and extension to do, and the two refer pain into overlapping territory. They are confused with each other so regularly that a study was built around exactly that confusion. It compared 60 people awaiting hip replacement with 60 awaiting spinal decompression, and groin pain came out with a sensitivity of 84.3 percent and a specificity of 70.3 percent for the problem being in the hip (Khan and colleagues, 2004).
What the sources read for this page do not show is that hip arthritis causes back pain. Coexistence, overlapping referral and a plausible mechanical story are not the same as cause, and that matters when the decision in front of you is which joint to have examined. Where the evidence does not settle a question, the answer is to put it to a clinician who can test both the hip and the spine in one appointment, and that is what we would do with it.
Sciatica is a narrower word than the way it usually gets used. It means pain following the sciatic nerve, typically with pins and needles, numbness or weakness in the leg or foot. A worn hip can send a dull ache down the leg, even below the knee, but it does not usually bring those nerve symptoms with it. If you have them, see sciatica.
If your legs get heavy or your calves ache when you walk any distance and the feeling goes when you sit or lean forward, read spinal stenosis instead, because that pattern is the spine's, not the hip's. For back pain without leg symptoms, low back pain is the starting point. Symptoms in both legs, numbness around the genitals or bottom, or any new change in bladder or bowel control is an emergency, and it is the first thing on the warning list below.
What happens when the wrong joint gets investigated?
Mostly, time passes. A scan of a knee in a 65 year old will nearly always show something. In 710 people over 50 whose knee X-rays showed no osteoarthritis at all, MRI found at least one abnormality in 89 percent, and the figure was barely lower in the knees that did not hurt (Guermazi and colleagues, 2012). A finding on a report tends to end the search. Treatment then gets aimed at the knee, which does not settle, and the explanation offered is that the treatment needs more time.
The series from the arthroplasty center is the sharp end of that: 12 of their 21 patients had surgical treatment on a knee that was not the problem (Dibra and colleagues, 2017). None of that means an investigation you have had was unnecessary, and your clinician had reasons neither you nor this page can see from here. The point is narrower: if a knee has been imaged and treated and is no better, the hip should be examined before the next step on the knee.
What to do next, and what to say at the appointment
A clinician can do a lot with plain observations, and these are the ones that help:
- Where the pain starts and where it travels, and whether it ever reaches the groin.
- Whether the knee is tender to press, and whether it swells, locks or gives way.
- Whether moving the hip reproduces the knee pain, and whether the hip feels blocked turning inward.
- How long morning stiffness lasts, and in which joints. NICE advises that from 45 onward osteoarthritis can usually be diagnosed without an X-ray when a joint aches with activity and there is either no morning stiffness at all or morning stiffness lasting no longer than 30 minutes.
- What has already been investigated and treated, and what happened.
One sentence to rehearse: "Can we check whether this knee pain is coming from my hip?" It is a reasonable question, it sits in the orthopedic literature as a known trap, and it takes a couple of minutes to examine.
If the hip turns out to be the source, the hip osteoarthritis program is the exercise side of treatment, treating hip arthritis without surgery covers the full non-surgical picture, and in a younger or more active hip with a pinching catch at the front, hip impingement covers a different diagnosis with a similar map.
When to see a physio or doctor
Book a routine appointment with a doctor or physio if knee or hip pain is affecting your sleep or your normal activities, keeps coming back, or has not improved after 2 weeks of self care at home (NHS). Ask for both joints to be looked at if the pain spans them, and say which investigations you have already had.
Some signs need faster help, from an emergency visit to a doctor within a few days. They are listed under the warning signs below, and the nerve signs at the top of that list come before anything on this page.
Related exercise programs
Warning signs
Get emergency help now
- Emergency: you have had a fall or an injury and now have severe hip pain, or you cannot walk or put weight on the leg. Call emergency services or go to an emergency department. This can be a sign of a broken hip (hip fracture).
- Emergency: tingling or loss of feeling in the hip or leg after a fall or injury. Call emergency services or go to an emergency department.
- Emergency: pain, tingling, numbness or weakness in both legs, numbness or altered feeling around your genitals or bottom, or new trouble peeing or controlling your bladder or bowels. The same applies if you lose feeling in one leg. Call emergency services or go to an emergency department straight away. These can be signs of pressure on the nerves at the base of the spine (cauda equina syndrome).
Get help today
- Same day: the hip is hot and swollen, or the skin over it has changed color, or you have hip pain with a high temperature or feel hot, cold or shivery. Get medical help the same day, and go to an emergency department if you feel very unwell. A joint infection needs treatment quickly. If you have a very high or very low temperature, shivering you cannot control, you are breathing very fast or finding it hard to breathe, you are confused or your speech is slurred, your skin, lips or tongue look blue, gray, pale or blotchy (on brown or black skin this can be easier to see on the palms of the hands or soles of the feet), or you have a rash that does not fade when you press it, call emergency services, as this can be sepsis.
- Same day: the knee is hot, red and swollen, or you have knee pain with a high temperature or feel hot, cold or shivery. Get medical advice the same day, and go to an emergency department if you feel very unwell. This can be a sign of infection in the joint, which needs treatment quickly. If you have a very high or very low temperature, shivering you cannot control, you are breathing very fast or finding it hard to breathe, you are confused or your speech is slurred, your skin, lips or tongue look blue, gray, pale or blotchy (on brown or black skin this can be easier to see on the palms of the hands or soles of the feet), or you have a rash that does not fade when you press it, call emergency services, as this can be sepsis.
- Same day: severe hip pain that came on suddenly without a fall, or pain that is getting worse quickly over a few days. Get medical advice the same day.
- Same day: new hip or groin pain after a fall, even a small one, if you are older, have low bone density (osteoporosis) or have taken steroid tablets for a long time, even if you can still walk. Get medical advice the same day. A broken hip is not always obvious at first.
- Same day: a leg or foot that is getting weaker, for example your foot drags, catches on the ground or slaps down when you walk (foot drop). Get medical advice the same day. If the weakness is getting worse by the hour, go to an emergency department.
- Same day: a child or teenager has sudden pain in the hip, thigh or knee, is limping, or cannot put weight on one leg. Get an urgent appointment with a doctor the same day. If they have a high temperature or seem very unwell, go to an emergency department. This page is for adults, and hip pain in children has different causes.
- Same day: hip or groin pain that is worse at night or does not ease with rest, and keeps getting worse. If you are being treated for cancer now, contact your cancer team the same day.
Book an appointment
- Within a day or two: hip or groin pain that is worse at night or does not ease with rest, and keeps getting worse. If you have had cancer, now or in the past, or are losing weight without trying, see your doctor sooner, within a day or two, and mention it. This applies even if the pain is not getting worse.
- Within a few days: hip or groin pain that is worse at night or does not ease with rest, and keeps getting worse. See your doctor within a few days.
- Within a few days: new groin or hip pain and you take steroid tablets long term, or have in the past, or you regularly drink a lot of alcohol. This can be a sign of a problem with the blood supply to the top of the thighbone (avascular necrosis). Book an appointment with your doctor within a few days and mention the steroids or alcohol.
- Within 2 weeks: pain that spreads down the leg below the knee, especially with numbness or tingling in the leg or foot. The pain may be coming from your lower back rather than the hip. Book an appointment with a doctor or physio.
Common questions
Can hip arthritis cause knee pain?
Yes. AAOS lists the knee among the places hip joint pain spreads to, and among 60 people waiting for a hip replacement, 47 percent reported pain below the knee (Khan and colleagues, 2004). That group had advanced arthritis, so the figure describes them, not every sore hip. The pattern is well enough known to have its own warning in the surgical literature, and still gets missed.
How does hip arthritis cause knee pain?
By two routes that are easy to confuse. One is referred pain: the hip joint sits deep, and pain from deep structures is reported over a region that includes the thigh and the knee. The other is mechanical. A hip that has lost movement makes the knee and the foot do more of the work of walking, and in the clinic that second kind usually hurts on the outside or the front of the knee and builds through the day rather than first thing.
How do I know if my knee pain is coming from my hip?
A few checks at home cover most of it. Press the knee all over: hip referral is usually not tender to touch. Move the hip, especially turning the leg inward, and see whether it reproduces the knee pain or feels blocked. Then ask whether the knee swells, locks or gives way, because those belong to the knee itself. None of this is a diagnosis, but it tells you which joint to ask about.
Can hip arthritis cause lower back pain?
The honest answer is that the sources read for this page do not settle it. What is documented is that the two are confused with each other often enough to be studied: a hospital study compared people waiting for a hip replacement with people waiting for spinal surgery and found groin pain had 84.3 percent sensitivity and 70.3 percent specificity for the hip being the problem (Khan and colleagues, 2004). A stiff hip also changes how you stand and walk, which is a reasonable mechanism, but reasonable is not the same as shown. Ask for both to be examined.
Can hip arthritis cause sciatica or pain down the leg?
Hip arthritis can send pain down the leg, including below the knee, but sciatica means something specific: pain along the path of the sciatic nerve, usually with pins and needles, numbness or weakness. Hip referral does not normally come with those. If you have them, sciatica is the page, and symptoms in both legs or any change in bladder or bowel control is an emergency, as the warning list below sets out.
Will treating the hip fix the knee pain?
It can, and sometimes completely. In the series of 21 people treated for knee pain that turned out to be hip arthritis, 14 had their knee pain resolve entirely after hip replacement (Dibra and colleagues, 2017). That was a small group at one specialist center, and 17 of the 21 had the hip replaced, so it does not tell you what exercise or any other treatment would do for your knee. It does show which joint was producing the pain.
Can hip arthritis cause pain in the other hip or the other knee?
Limping loads the good side harder, and people often report the other knee or hip starting to complain in a bad spell. The sources on this page did not measure that, so treat it as something to raise, not something proven. Osteoarthritis also commonly affects more than one joint in its own right, which is a different explanation for the same observation and needs an assessment to tell apart.
References
- Dibra FF, Prieto HA, Gray CF, Parvataneni HK. Don't forget the hip! Hip arthritis masquerading as knee pain. Arthroplasty Today. 2017;4(1):118-124. https://doi.org/10.1016/j.artd.2017.06.008
- Khan AM, McLoughlin E, Giannakas K, Hutchinson C, Andrew JG. Hip osteoarthritis: where is the pain? Annals of the Royal College of Surgeons of England. 2004;86(2):119-121. https://doi.org/10.1308/003588404322827518
- Kim C, Nevitt MC, Niu J, et al. Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study. BMJ. 2015;351:h5983. https://doi.org/10.1136/bmj.h5983
- Guermazi A, Niu J, Hayashi D, et al. Prevalence of abnormalities in knees detected by MRI in adults without knee osteoarthritis: population based observational study (Framingham Osteoarthritis Study). BMJ. 2012;345:e5339. https://doi.org/10.1136/bmj.e5339
- National Institute for Health and Care Excellence. Osteoarthritis in over 16s: diagnosis and management (NG226). 2022. https://www.nice.org.uk/guidance/ng226
- American Academy of Orthopaedic Surgeons. Osteoarthritis of the hip. OrthoInfo. https://www.orthoinfo.org/en/diseases--conditions/osteoarthritis-of-the-hip/
- NHS. Hip pain in adults. https://www.nhs.uk/symptoms/hip-pain/
Written and checked by the PocketPhysio editorial team. Last updated 2026-10-18.
This page is general education, not a diagnosis or a personal treatment plan. See a physiotherapist or doctor for advice about your own situation.