An arthritic hip can cause pain in the lower back. A lumbar disc can cause pain in the groin. These are two documented facts, and together they explain why some pain that "won't go away" is treated in the wrong place for months.
Around these two facts, however, a mythology has grown up: the twisted pelvis, legs of unequal length, the misalignment that needs correcting. This article keeps the two things apart: what the studies really show and what we keep repeating without evidence.
⚠ Important: read this before continuing
The exercises and advice in this article are general guidance and may not suit your situation. Every person has a unique clinical history: what works for others could be counterproductive for you.
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Why hip and spine get confused
In orthopaedics the problem has a name, hip-spine syndrome, and it comes from a simple observation: hip arthritis and lumbar degeneration are both common after the age of sixty, so they often occur in the same person. When the symptoms resemble each other, working out which of the two structures is generating the pain becomes the real clinical problem. The leading review on the topic is explicit that this requires an accurate clinical history, a physical examination and, where needed, selective diagnostic tests to decide which problem to address first.
A second review, more focused on rehabilitation, adds an honest and not very reassuring observation: the literature on this subject is scattered across different disciplines that use different terminology, and this inconsistency makes it hard to tell what is really proven. It is a useful reminder: "hip and back are connected" is true, but it is not yet a diagnosis.
Where a diseased hip hurts (spoiler: not only the hip)
Here the data are good. A prospective observational study asked 113 patients waiting for a hip replacement to draw on a body map where they felt pain, before and after the operation. The most frequent sites were the groin, front of the thigh, buttock, front of the knee and greater trochanter. But 21.2% also marked the lower back, 7.1% the shin and 2.7% the calf: areas that are not usually considered sites of referred pain from the hip. Low back pain was more common in people who had had hip symptoms for longer.
In plain terms: if you have pain in the groin or buttock and you have been told it is "sciatica", it is worth reconsidering. And if you have low back pain together with stiffness and hip pain, the hip is not a minor detail.
The most interesting evidence: what happens to the back after a hip replacement
If the lower back pain comes from the hip, replacing the hip should make it disappear. It is a natural experiment, and three studies have measured it.
In the cohort of 113 patients, 97.3% reported complete relief within 12 weeks of surgery, at every site, the lower back included. In a prospective study of 344 patients, almost half (49.4%) had low back pain before surgery: it resolved in 113 of 170 cases, that is 66.4%. In a more recent series of 500 hip replacements, back pain present in 41% of patients resolved in 82.4% at one year.
These are remarkable numbers, but they need reading with three caveats.
First, none of these studies has a control group: they are surgical cohorts, not randomised trials, and part of the improvement may come from walking normally again, from changes in medication or simply from time. Second, they are selected populations, and the authors themselves state the criteria: the study with 97.3% success had excluded from the outset anyone with concurrent knee or spinal disease, and the one with 82.4% had excluded anyone who had already had back surgery. Third, and most importantly, the other side of the coin exists: in the study of 344 patients, a third of those with low back pain kept it, and 20% of those who did not have back pain beforehand developed it within a year of surgery. Pain radiating below the knee was the sign most associated with a pre-existing spinal condition.
So: in a person with advanced hip arthritis, a real share of back pain does come from the hip. From there to saying the hip is the hidden cause of common low back pain is a leap these studies do not justify.
What is not proven
This is the part that is usually missing from articles on the subject.
The "misaligned pelvis" and the wrong posture. A systematic review with meta-analysis compared static posture measures across 5,097 people with low back pain and 6,974 without. Pelvic tilt was slightly greater in people with back pain, but the difference is small (SMD 0.23) and the heterogeneity between studies very high (I² 72%). Lumbar lordosis, sacral slope and pelvic incidence showed no statistically significant differences. The authors' conclusion is verbatim: lumbopelvic mechanisms may be altered, but no firm conclusions can be drawn. With differences this small and groups that almost completely overlap, none of these parameters reliably distinguishes people with back pain from those without.
Legs of unequal length. In the same meta-analysis, lower limb discrepancy showed no difference between people with back pain and those without: it was distributed in the same way in both groups. Some observational studies do report an association with low back pain, scoliosis and arthritis, but they are the same studies that the systematic review dedicated to shoe lifts rates as very low or poor quality. That review found ten studies in all, of which only one was randomised and involved 22 treated participants. Its conclusion is that there is low-quality evidence that lifts reduce pain in people who already have a discrepancy and a painful problem, which is not the same as showing that the discrepancy caused that pain. If you have two slightly different legs, that is not automatically the explanation for your case. The picture changes if the shorter leg belongs to a child who is still growing: then the size in millimetres and how much growth remains matter, and this is explained in when a shorter leg really matters in a child.
The "compensations" explained on the whiteboard. The story of a stiff hip forcing the spine to move more is plausible and useful for reasoning, but it remains a model. The biomechanical differences that are actually measured between people with and without back pain come from cross-sectional studies: they photograph two groups at the same moment and do not tell us what came first. A stiff hip may have contributed to the back pain, or it may be the result of months in which you moved less because it hurt.
Hip mobility and low back pain: a weak association
It is worth being precise here too, because "improve hip mobility and the back gets sorted" is a sentence that circulates widely.
A systematic review examined 24 studies on the association between hip joint range of motion and non-specific low back pain. The only movement consistently found to be reduced in patients was internal rotation. The authors' overall rating of the quality of the evidence is "very low", with recurring problems of sample size, assessor blinding and lack of adjustment for confounding factors. A more recent and broader review, of 54 observational studies of moderate to high methodological quality, confirms the picture: people with low back pain show less hip internal rotation, weaker hip abductors and extensors, and different muscle activation patterns. Here too, though, these are observational studies, and the authors had to forgo a meta-analysis because of heterogeneity in the data.
The practical message does not change much: it is worth assessing the hip in people with back pain. But the promise changes a great deal: "it often fixes back pain" is not a claim these data support.
When the back is what hurts the hip
The opposite direction is less often discussed but clinically frequent. The low lumbar nerve roots also supply the hip region, so nerve root irritation can be felt in the groin, buttock or thigh and pass for a joint problem. Lumbar spinal stenosis is the other great imitator: pain in the buttocks and legs that appears when walking and eases when sitting or bending forward.
With the sacroiliac joint, caution is needed: it is a recognised source of pain, but manual tests taken individually are not enough to make a diagnosis, and the same is true of the so-called piriformis syndrome, which remains a diagnosis of exclusion that is debated and has no shared reference test. If someone has explained your pain with one of these two labels after five minutes of palpation, the certainty was excessive.
Signs for which you do not do exercises, you see a doctor
The great majority of back pain has no identifiable specific cause, and only a small share is due to a well-defined condition such as a fracture, tumour or infection. Precisely because they are rare, these signs need to be recognised straight away.
Go to the emergency room, today, if you develop: loss of bladder or bowel control, difficulty passing urine, numbness in the area that rests on a bicycle saddle (perineum, genitals, inner thighs), or weakness in one or both legs that is getting worse. This is the picture of cauda equina syndrome, a surgical emergency: time matters.
Ask for a medical assessment without waiting for it to pass if you have: a recent trauma, even a modest one if you have osteoporosis or take corticosteroids; fever, shivering or night sweats; a personal history of cancer; unintended weight loss; or pain that does not change in any position, not even at night.
One honest clarification, because it helps you use this list well. The review of international guidelines counted 46 different red flags, with little agreement on which to adopt and accuracy data rarely available; a Cochrane review on vertebral fracture found that only a few signs (advanced age, trauma, corticosteroid use) really shift the probability, and that combinations matter more than single signs. This means a single sign is not a diagnosis and should not make you think the worst. It does not mean it should be ignored: it means it should be taken to a doctor rather than to a search engine.
What to do, in practice
Outside the cases above, the first step is to work out what is generating the pain, because hip and spine are treated in different ways. A useful, free clue: notice what changes the symptoms. Groin pain that gets worse when you rotate the hip, cross your legs or get up from a car points towards the hip; pain that changes with bending or extending the trunk, or that radiates below the knee, points towards the spine.
On treatment, the evidence is more solid than people think, and it is the same from both sides: movement.
For chronic low back pain, a Cochrane review of 249 randomised trials shows that exercise reduces pain compared with no treatment, usual care or placebo, with a mean difference of 15 points out of 100 and moderate certainty of the evidence. On disability the effect is smaller, below the threshold the authors had set as clinically relevant, and in comparison with other conservative treatments the advantages exist but are modest: exercise is probably better than information alone or electrotherapy, while no differences emerge compared with manual therapy.
For hip arthritis, a second Cochrane review included ten randomised trials and reports, based on nine of them (549 participants), high-quality evidence that land-based exercise reduces pain by about 8 points out of 100 and improves function by about 7, with a benefit that lasts for at least three to six months after the end of the supervised programme. The number of people to treat for one to benefit is 6.
These are real but modest effects, not miracles. Since the advantages of one approach over another are small, the practical choice is the one you can sustain for weeks: hip mobility in all directions, internal rotation included, strengthening of the glutes and trunk muscles with loads that increase over time, and walking. Progression matters more than the exercise chosen.
How a remote assessment works
A physiotherapist on a video call can take your clinical history, have you perform the movements that reproduce the pain, observe how you move and work out whether the picture is more hip or more lumbar, while also recognising the signs that require a doctor. It is often enough to set up a programme and adjust it over time.
There are limits to declare: some tests require hands-on work, and when an imaging study or a diagnostic injection is needed (which in hip-spine syndrome remains one of the tools for working out what is generating the pain), the route goes through an orthopaedic surgeon or a rehabilitation specialist. In that case, the job of whoever assesses you is to tell you so, not to keep you in sessions.
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Further reading: Back and Gut: The Surprising Connection.
Sources
- Devin CJ, McCullough KA, Morris BJ, et al.: Hip-spine syndrome, Journal of the American Academy of Orthopaedic Surgeons, 2012
- Prather H, van Dillen L.: Links between the Hip and the Lumbar Spine (Hip Spine Syndrome) as they Relate to Clinical Decision Making for Patients with Lumbopelvic Pain, PM&R, 2019
- Hsieh PH, Chang Y, Chen DW, et al.: Pain distribution and response to total hip arthroplasty: a prospective observational study in 113 patients with end-stage hip disease, Journal of Orthopaedic Science, 2012
- Parvizi J, Pour AE, Hillibrand A, et al.: Back pain and total hip arthroplasty: a prospective natural history study, Clinical Orthopaedics and Related Research, 2010
- Vigdorchik JM, Shafi KA, Kolin DA, et al.: Does Low Back Pain Improve Following Total Hip Arthroplasty?, The Journal of Arthroplasty, 2022
- Sugavanam T, Sannasi R, Anand PA, Ashwin Javia P.: Postural asymmetry in low back pain: a systematic review and meta-analysis of observational studies, Disability and Rehabilitation, 2025
- Campbell TM, Ghaedi BB, Tanjong Ghogomu E, Welch V.: Shoe Lifts for Leg Length Discrepancy in Adults With Common Painful Musculoskeletal Conditions: A Systematic Review of the Literature, Archives of Physical Medicine and Rehabilitation, 2018
- Avman MA, Osmotherly PG, Snodgrass S, Rivett DA.: Is there an association between hip range of motion and nonspecific low back pain? A systematic review, Musculoskeletal Science and Practice, 2019
- Pizol GZ, Miyamoto GC, Cabral CMN.: Hip biomechanics in patients with low back pain, what do we know? A systematic review, BMC Musculoskeletal Disorders, 2024
- Hartvigsen J, Hancock MJ, Kongsted A, et al.: What low back pain is and why we need to pay attention, The Lancet, 2018
- Verhagen AP, Downie A, Popal N, Maher C, Koes BW.: Red flags presented in current low back pain guidelines: a review, European Spine Journal, 2016
- Han CS, Hancock MJ, Downie A, et al.: Red flags to screen for vertebral fracture in people presenting with low back pain, Cochrane Database of Systematic Reviews, 2023
- Hayden JA, Ellis J, Ogilvie R, Malmivaara A, van Tulder MW.: Exercise therapy for chronic low back pain, Cochrane Database of Systematic Reviews, 2021
- Fransen M, McConnell S, Hernandez-Molina G, Reichenbach S.: Exercise for osteoarthritis of the hip, Cochrane Database of Systematic Reviews, 2014
Last source check: August 2026.
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