IS IT THE HIP OR THE BACK?
A worn hip refers into the buttock. A bad back refers into the groin. They get treated as each other for years.
This is one of the most common misattributions in musculoskeletal medicine, and it is resolved in about four minutes of examination that frequently does not happen.
Where each one usually sends pain
- Hip osteoarthritis classically hurts in the groin, sometimes down the front of the thigh to the knee, and is worse on weight-bearing, pivoting and putting on shoes and socks.
- Lumbar spine classically hurts across the low back and buttock and, when a root is involved, travels below the knee in a defined line.
- Both refer into the lateral hip and buttock, which is the overlap zone and the reason the confusion exists.
A third structure sits in the middle of the argument. Greater trochanteric pain syndrome — gluteal tendinopathy, often miscalled bursitis — produces point tenderness over the bony prominence of the hip and pain lying on that side at night. It is neither joint and responds to neither joint’s treatment.
The examination that settles it
- Passive internal rotation of the hip. Reduced range and reproduction of groin pain is the most useful single hip test there is.
- FABER and FADIR to load the joint in flexion with rotation.
- Lumbar extension and rotation to load the facets, and a straight leg raise for root tension.
- Palpate the greater trochanter and the sacroiliac line directly.
- Watch the gait. An antalgic hip gait and a spinal gait look different, and this is where eyeballing gets replaced by actually watching.
Where examination genuinely cannot separate them — and sometimes it cannot, because people are allowed to have both — an image-guided diagnostic injection into one structure answers it. Relief localizes the generator. That is a test, not a treatment, and it is worth doing before anyone operates on either.
Why getting it wrong is expensive
A lumbar fusion performed for pain that was coming from a hip does not help, and it is irreversible. A hip replacement performed for pain that was coming from L4-5 does not help either. Both happen, and both are the predictable consequence of treating the region that was imaged rather than the structure that was tested.
There is a subtler version worth knowing. When both are degenerate, fixing the hip can unmask the spine or vice versa, and patients are then told their operation failed. It did not fail; it treated one of two problems.
Common questions
Can hip arthritis cause low back pain?
Yes, indirectly and commonly. A stiff hip forces the lumbar spine to make up the missing motion, and the segments above take load they were not designed for.
If my X-ray shows hip arthritis, is that the cause?
Not necessarily. Radiographic hip arthritis is common in people with no hip pain, exactly as lumbar degeneration is. It earns significance only by matching the examination.
Which do I treat first if I have both?
Usually whichever is more clearly the dominant generator on testing, and often the one that is limiting function most. That is a conversation, and it should be an explicit one.
Related reading
- One-sided low back pain
- Sacroiliac joint pain
- What impersonates sciatica
- What happens at the first visit
Ask to have your hip examined at a spine appointment
It takes a few minutes and it prevents a category of error that costs people years.
12174 Natural Bridge Rd, Suite 301
St. Louis, MO 63044
At DePaul Hospital on Natural Bridge Road, inside the I-270 and I-70 interchange, on the west side of the airport.
Sources
- Devin CJ et al. Hip-spine syndrome. The Journal of the American Academy of Orthopaedic Surgeons, 2012. PubMed 22751162
- Chavarria JC et al. The Hip-Spine Challenge. The Journal of bone and joint surgery. American volume, 2021. PubMed 34612850
- Merle C et al. [Hip-spine syndrome]. Der Orthopade, 2020. PubMed 32974737
- Vaswani R et al. Hip-Spine Syndrome in the Nonarthritic Patient. Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 2022. PubMed 35550420