Five features identify hip osteoarthritis: pain deep in the groin rather than the outer hip, lost rotation that makes socks and shoes awkward, cupping the hand around the hip crease when describing it, morning stiffness under half an hour, and pain referring down to the knee. Exercise helps, and honestly the average benefit is modest. Staying mobile is what it buys.
Where the pain sits on the outer hip and stops you lying on that side at night, that is a different problem, and it is set out in PhysioHub’s guide to hip pain causes and relief.
Hip osteoarthritis is diagnosed clinically far more often than it is diagnosed on a scan. These are the five features that do the work, ranked by how strongly each one points at the joint itself.
| Sign | What it means | How to check it | How strongly it points at the hip joint |
|---|---|---|---|
| 1. Groin pain | The joint itself, rather than tissue around it | Where would you press to show someone? | Strongly |
| 2. Lost internal rotation | Restricted movement inside the joint | Socks, shoes, getting out of a low car | Strongly, the most reliable sign |
| 3. The C-sign | People cup the hand round the hip crease | Watch what your hand does when you describe it | Moderately |
| 4. Morning stiffness under 30 minutes | Degenerative rather than inflammatory | Time it | Moderately, and it rules things out |
| 5. Pain referring to the knee | Shared nerve supply, not a knee problem | Does hip rotation reproduce the knee pain? | Supportive |
Pain on the bony point of the outer hip, especially where you cannot lie on that side at night, points instead at gluteal tendon pain, which is more common than hip osteoarthritis.
This is a documentary review of published trial evidence and national guidance rather than a diagnosis of your hip. The five features here are the ones that carry the most weight clinically. Considered and left out as less useful for self-recognition: pain on the FABER and FADIR test positions, antalgic gait, leg length differences, and the radiographic grading systems, which correlate poorly with symptoms.
The order reflects how strongly each feature points at the hip joint itself rather than the tissues around it.
The sources read were the 2026 Cochrane review of exercise for hip osteoarthritis by Hall and colleagues, covering 18 trials and 1,368 participants, and NICE guideline NG226 on osteoarthritis. Evidence checked in August 2026.
What could not be checked, and what this page states rather than glosses: the Cochrane effect on pain was around 7 points on a 100-point scale, below the roughly 12 points usually taken as noticeable, quality of life showed little to no improvement, and the estimate weakened further when exercise was compared with a sham treatment rather than with usual care. Most included trials were small and unblinded. Exercise is still recommended, for reasons the review authors set out plainly: it is low risk and it carries benefits beyond the hip. Hip pain after a fall, an inability to weight-bear, or night pain with fever or unexplained weight loss all need assessing urgently rather than exercising.
Stages describe an X-ray, not a person. They run from superficial cartilage wear with a normal joint space, through narrowing and small bone spurs, to bone-on-bone contact. They are a radiologist’s vocabulary that has escaped into patient conversations.
The correlation with symptoms is loose in both directions. Marked changes with manageable pain is common. Minor changes with substantial pain is also common. Treating the picture rather than the person is the mistake NICE guidance is written to prevent.
What actually changes the plan is how far you can walk, whether it wakes you at night, whether you can manage stairs and shoes, and whether the things you care about are being given up. Those are the measures a decision about surgery is made on.
Progression is not inevitable or linear. Symptoms fluctuate over months and many people plateau for years. A stage on a report says nothing about what next year looks like.
What it is
A deep ache felt in the groin crease and the front of the thigh, coming from inside the joint capsule.
How you notice it
Asked to point at it, you press into the crease at the front rather than the bony point on the side. It is often described as deep, dull and hard to localise precisely.
Why it matters
Location is the first fork in the road. Groin pain points inside the joint. Pain on the bony point of the outer hip points at the gluteal tendons, which is both more common and treated differently. Getting this wrong sends people down the wrong path for months.
What helps
Regular movement on level ground, hip and thigh strengthening two or three times a week, and raising seat heights so the hip is not forced into deep bend to stand up.
What the evidence supports
NICE makes therapeutic exercise and weight management the core treatments, with manual therapy considered only for hip and knee osteoarthritis and only alongside exercise rather than instead of it.
Why it ranks first
It is the feature that separates hip osteoarthritis from the condition it is most often confused with, and that distinction changes everything that follows.
What it is
Reduced ability to turn the thigh inwards at the hip, which is the first movement an arthritic hip loses.
How you notice it
Putting on socks and shoes becomes a manoeuvre. Getting out of a low car takes planning. Cutting toenails on that side is awkward. Sitting cross-legged becomes uncomfortable or impossible.
Why it matters
This is the most reliable clinical sign of hip osteoarthritis and the one a physiotherapist checks first. Restricted rotation with groin pain is a strong combination; normal rotation makes a hip joint problem considerably less likely and pushes the search towards the back or the outer hip.
What helps
Daily gentle rotation work within comfort, done unloaded, and building strength around the hip to protect what range there is. Adaptations for socks and shoes are worth adopting early rather than treated as giving in.
What the evidence supports
Range work maintains function rather than reversing the joint change. That is a modest claim and an honest one.
Why it ranks second
It is the most specific of the five, it is easy to check at home, and losing it is what actually interferes with daily life.
What it is
The gesture people make when describing hip pain: cupping the hand in a C shape around the hip, with the thumb behind and the fingers into the groin.
How you notice it
Watch your own hand next time you explain where it hurts. People with pain coming from inside the joint tend to grip around the hip. People with outer hip tendon pain point with one finger at the bony bump.
Why it matters
It is a fast, free piece of information that supports the groin-pain finding. It is a supporting sign rather than a test, and it should never outweigh what rotation testing shows.
What helps
Nothing directly. Its value is in pointing the assessment in the right direction on the first minute rather than the tenth.
What the evidence supports
This is a clinical observation rather than a validated test, and it is presented here as such.
Why it ranks third
It costs nothing to notice and it genuinely helps sort intra-articular hip pain from the tissues around it.
What it is
A stiff, gripped feeling in the hip on waking that loosens as you move around, typically inside half an hour.
How you notice it
The first trip to the bathroom is the worst part of the day, and by the time you have made a cup of tea the hip has eased.
Why it matters
The duration is what carries the information. Under 30 minutes fits osteoarthritis. Well over an hour, particularly with several joints involved and visible swelling, points at inflammatory arthritis, which needs blood tests and a different treatment pathway.
What helps
Moving early rather than easing into the day slowly. A few minutes of gentle hip movement before getting up, or a short walk soon after, shortens it noticeably.
What the evidence supports
A descriptive feature. Its clinical value is in ruling other things in or out rather than in guiding treatment.
Why it ranks fourth
It is useful and it is not specific to the hip. Timing it, though, is one of the few things you can do at home that genuinely changes which condition is being considered.
What it is
Pain from the hip joint felt down the front or inside of the thigh and into the knee, because the nerves supplying the hip also supply that region.
How you notice it
The knee aches but nothing about the knee itself is tender, swollen or restricted. Moving the hip reproduces the knee pain.
Why it matters
It is a well-recognised trap. People present with knee pain, the knee is investigated, and the hip is the source. It is worth checking hip rotation in anyone with unexplained knee pain, and it takes about thirty seconds.
What helps
Treating the hip. The knee needs nothing of its own where this is the mechanism.
What the evidence supports
Referred pain patterns from the hip are well described anatomically and clinically. There is no trial to cite, and none is needed for the practical point.
Why it ranks fifth
It is the least common of the five and the one most likely to send an investigation to the wrong joint entirely.
| Sign | Points at the joint | Checkable at home | Also seen in outer hip tendon pain | Changes the plan |
|---|---|---|---|---|
| Groin pain | Strongly | Yes | No | Yes, it sets the direction |
| Lost internal rotation | Strongly | Yes, socks and shoes | No | Yes |
| The C-sign | Moderately | Yes | Rarely | Supports the others |
| Morning stiffness under 30 min | Moderately | Yes, time it | Sometimes | Rules inflammatory causes out |
| Referred knee pain | Supportive | Partly | No | Yes, stops the wrong joint being treated |
The first two carry most of the weight. Groin pain with restricted rotation is close to a working diagnosis; either one alone is not.
If you have groin pain and struggle with socks and shoes, start hip and thigh strengthening two or three times a week and adopt the sock and shoe adaptations now rather than later.
If the hip is sore most days at the moment, use water or a bike for the aerobic side and keep the strength work going at reduced load. Our hip exercise sheet covers the loading options.
If you have been given a stage from an X-ray, treat it as background. What decides the plan is how far you can walk, whether it wakes you and what you have stopped doing.
If your knee aches and nothing about the knee is tender or swollen, get hip rotation checked before the knee is investigated further.
If morning stiffness lasts well over an hour, or several joints are involved, see a GP. That is a different condition.
If pain now wakes you regularly and the things you care about have gone, that is the conversation about surgery. Our guide to hip replacement rehab covers what follows it.
The question that arrives most often with a hip is when it stops being a physiotherapy problem and becomes a surgical one. The local waiting figures give part of the shape of it. As of the June 2026 figures published by the East Sussex MSK Community Partnership, the average wait to see an advanced practitioner about a hip was 10.1 weeks, and to see an orthopaedic consultant about a hip, 7.9 weeks. Those are the two doors, and self-referral means neither needs a GP appointment first.
The honest clinical answer is that the referral point is set by your life rather than by your X-ray. A hip that still lets you walk the distances you want, sleep through the night and manage stairs is a hip to keep training, even where a scan looks unpromising. A hip that has taken away the walking, the sleep and the shoes has usually stopped responding to the things that work earlier, and the strength built before an operation is not wasted, because it shortens what comes after one. That is the case for keeping the programme going while a referral is in progress rather than waiting.
Where a hip needs the load rebuilding carefully rather than guessed at, our 1:1 rehab and strength training sessions are built for exactly that.
How can I tell if my hip pain is osteoarthritis?
Four features together make it likely: pain felt deep in the groin or front of the thigh, difficulty putting on socks and shoes because the hip will not rotate, morning stiffness that eases within about half an hour, and pain that has built over months or years rather than arriving suddenly. Pain on the bony point of the outer hip that stops you lying on that side is a different problem, and it is more common.
How much does exercise help hip osteoarthritis?
Less than it helps some other joints, and it is still worth doing. A 2026 Cochrane review of 18 trials and 1,368 participants found exercise reduced pain by around 7 points on a 100-point scale compared with no treatment or usual care, where roughly 12 points is generally taken as the threshold for a difference people notice. The review authors were explicit that clinicians should be honest that the average benefit may be modest, while exercise remains recommended for its low risk and its wider health benefits.
What are the stages of hip osteoarthritis?
Stages are a description of what an X-ray shows: joint space narrowing, bone spurs and changes in the bone underneath, running from minor to bone-on-bone. They are useful shorthand and a poor guide to treatment. NICE is clear that osteoarthritis should be diagnosed and managed on symptoms rather than on imaging, because many people with marked changes on a scan have manageable symptoms and some with minor changes have a great deal of trouble.
Why does hip arthritis cause knee pain?
The nerves supplying the hip joint also supply the inner thigh and knee, so pain from the hip is commonly felt further down the leg. It is a frequent reason people arrive convinced they have a knee problem when the hip is the source. Testing hip rotation usually settles it in under a minute.
How do I put my socks on with a stiff hip?
Cross the ankle over the opposite knee rather than pulling the knee up towards your chest, which asks for far less bending at the hip. A long-handled shoehorn, elastic laces and a sock aid remove the problem entirely, and using them is a sensible adaptation rather than a defeat.
Do I need surgery if my X-ray shows severe hip arthritis?
No, not on the strength of the X-ray. Surgery is considered when pain is limiting the life you want, disturbing your sleep regularly, and no longer responding to exercise, weight management and pain relief. Plenty of people with severe changes on imaging manage well for years, and building strength beforehand improves the recovery if it does come to a replacement.
Is walking or swimming better for hip osteoarthritis?
Both help, and they do different jobs. Walking maintains general health and bone and is usually well tolerated on level ground. Water lets a stiff hip move through more range with almost no load, which makes it valuable during a bad spell. Neither replaces strengthening the muscles around the hip, which is the part with the most direct evidence.
PhysioHub – Empowerment through Evidence-Based Education.
Every body is different. Book a thorough assessment and get advice that is specific to you and your goals.
Book an Appointment