Hip Pain

Groin pain: Usually the hip joint itself, and the pattern that responds to replacement.
Outer hip pain: Usually tendons and bursa over the bone, not the joint.
Buttock pain: Often the spine or the sacroiliac joint rather than the hip at all.

The pelvis and hips, showing the ball and socket joint deep in the groin, the bursa over the bony point on the outside, and the sciatic nerve behind. — The joint sits deep and central. The bursa, shown in blue, lies over the bony point on the outside, and the sciatic nerve runs behind both.

The three structures that produce most hip pain are in three different places. The ball sits in its socket deep in the groin; the bursa and the gluteal tendons lie over the greater trochanter, the bony point you can feel on your side; the sciatic nerve passes behind, on its way to the leg.

That is why pointing matters more than the word “hip”. The same complaint can mean any of the three, and each is treated differently.

Where exactly is it?

Three areas, three different problems. Getting this right is the difference between treating the joint and treating the tendons over it.

Groin and front of the thigh

Hip osteoarthritis — deep ache, stiff first thing, hard to put on socks or get out of a car
Labral tear or impingement — catching or clicking, pain on deep bending, often younger and active
Hip flexor strain after sprinting or kicking
Loss of blood supply to the bone — uncommon, but groin pain that is worsening steadily deserves a scan

Outer hip, over the bony point

Gluteal tendon problems and bursitis — the commonest cause of outer hip pain by some distance
Painful to lie on that side, and sore climbing stairs or standing up
Pain may run down the outside of the thigh, sometimes as far as the knee

Buttock and back of the hip

Referred from the lower back — see lower back pain and sciatica
Sacroiliac joint pain, felt just beside the dimple at the base of the spine
Deep buttock pain from the piriformis muscle, which can mimic sciatica
Hamstring tendon pain at the sitting bone, sore on sitting and driving

The one that confuses everyone

A worn hip often announces itself at the knee. Thigh or knee pain with no knee findings is a hip problem until proven otherwise
It is worth examining the hip whenever the knee looks normal on its own scans

The single most useful test at home: can you put on a sock and shoe on that side as easily as the other? Losing that, along with groin pain, is the classic picture of a worn hip joint.

When hip pain needs attention quickly

After a fall, if you cannot bear weight, or the leg looks shorter or turned outwards, go to an emergency department. That is a fracture until proven otherwise, and it is more common in older adults with osteoporosis, sometimes after a surprisingly minor fall.

A hot, swollen, very painful hip with fever should be seen the same day.

How hip pain is assessed

History. Where it sits, what you can no longer do, and how far you can walk
Examination. Movement and rotation of the joint, tenderness over the bony point, tests for the tendons, and the back and sacroiliac joint
X-ray. Standing films show joint space and alignment; this answers the arthritis question in most people
MRI. For tendons, the labrum, or where the X-ray looks normal but the pain persists
Blood tests where inflammatory arthritis or infection is possible

Hip pain treatment

What helps depends entirely on which of the three areas is responsible. Tendon problems and joint wear need almost opposite advice.

Outer hip tendon pain

Loading the tendon gradually rather than resting it, avoiding positions that compress it — crossing the legs, standing on one hip, lying on that side — and an injection where progress has stalled.

Joint wear

Activity that keeps the joint moving without pounding it, strengthening, weight management, and pain relief used deliberately rather than continuously.

Injections

A guided injection can settle a tendon or a painful joint enough for rehabilitation to work, and sometimes helps confirm where the pain is coming from.

When surgery is considered

Hip replacement for arthritis that limits walking, sleep and daily life once other treatment has been tried. Keyhole surgery in selected cases for a labral tear or impingement.

Your surgeon

Hip problems here are seen by Dr Kelvin Tan Guoping, an orthopaedic surgeon whose subspecialty is hip and knee. He is a Fellow of the Royal College of Surgeons of Edinburgh, holds a Master of Medicine in orthopaedics, and is an Adjunct Assistant Professor at NUS. He consults in English, Mandarin, Teochew and Hokkien.

Most hip pain is not a replacement. Outer hip tendon problems are commoner than joint wear, and they are managed without surgery.
Robotic and computer-navigated replacement, after an international fellowship in Brisbane in 2017 under Professor Ross Crawford. He is a certified robotic trainer.
Complex and revision work, including peri-prosthetic fractures, from his time with the Adult Reconstruction Service at Tan Tock Seng Hospital.

When to see someone about it

Groin pain with stiffness, or trouble putting on socks and shoes
Pain lying on that side at night
Walking distance shrinking, or a limp that has become habitual
Catching, clicking or giving way
Thigh or knee pain with nothing wrong at the knee

Why see us about it

The hip, the back and the sacroiliac joint are examined together, because buttock pain is so often not the hip.
Tendon before joint. Outer hip pain is treated as a tendon problem unless the examination says otherwise.
Replacement is the last step, not the opening offer.

Common questions

I point at the side of my hip. Is that the joint?

Usually not. The joint sits deep in the groin, and pain over the bony point on the side is more often the gluteal tendons and the bursa that sit over it.

Why does my knee hurt if the problem is my hip?

The hip refers pain down the thigh, and sometimes to the knee. Knee pain with normal knee findings is a reason to examine the hip.

Should I rest a painful hip?

Rarely. Tendon problems settle with graded loading rather than rest, and a worn joint stiffens if it is not moved. What helps is changing the activity, not stopping.

Do I need an X-ray?

For suspected arthritis, a standing X-ray usually answers the question. Tendon and labral problems are better seen on MRI, and neither is ordered unless the result would change the plan.

Will I need a hip replacement?

Most people with hip pain do not. Replacement is considered for arthritis that limits walking and sleep once other treatment has been tried.

Do I need a referral to see a hip pain doctor?

No. Bring any X-ray or MRI reports, and be ready to point to exactly where it hurts.

Related conditions

Sacroiliac joint dysfunction · Lower back pain · Sciatica · Knee pain · Osteoporosis · Gout