Hip arthritis: the commonest cause from mid-lifeStrong evidence
The NHS pairs "over 45 years of age, pain worse when walking and stiffness after moving" with osteoarthritis, and the National Institute for Health and Care Excellence (NICE) diagnoses it without imaging in people 45 or over with activity-related pain and morning stiffness of 30 minutes or less. The NHS says hip arthritis causes pain in the groin or the outside of the hip, more pain and stiffness after the joints have been still for a while, and trouble with shoes and socks or getting in and out of a car.
Sources 1, 2, 3, 4
Outer hip pain: walking is often what it limitsEmerging evidence
Outer hip pain (greater trochanteric pain syndrome, mostly gluteal tendinopathy) is commonest in women aged 40 to 60, NHS inform says; in 3,026 adults aged 50 to 79, 15% of women and about 7% of men had it on one side. NHS inform lists pain that increases with walking and standing, pain standing on the affected leg ("hanging on the hip") and sitting with crossed legs, and says longer walks or a faster pace can bring it on. In the LEAP trial, walking was the activity people most often said it limited (68% of 201).
Each step puts your weight through one hip. In a study of 40 people with outer hip pain and 40 without, those with pain walked with more sideways load on the hip, more dropping of the pelvis and more lean of the trunk, and the LEAP trial's protocol explains that weak hip muscles let the hip drift inwards on one leg, squeezing the tendons against the bone.
Sources 5, 6, 7, 8, 9
Hip joint pain isn't only in the groinEmerging evidence
In 51 people whose hip joint pain was confirmed with an injection, the pain was felt in the buttock (71%), the thigh (57%), the groin (55%) and below the knee (22%), but never in the lower back. NHS inform adds that a back problem can cause hip pain even when the back doesn't hurt.
Sources 10, 11
Pain on walking that eases with rest: arteries or spine?Strong evidence
Narrowed leg arteries (peripheral arterial disease) cause an ache in the legs when walking that usually goes after a few minutes' rest. It's usually felt in the calf, but NHS leaflets say it can be felt in the thigh or buttock too. The NHS says see a GP if you get recurring leg pain when exercising.
If the pain needs sitting or bending forward to ease, rather than just standing still, the spine is more likely: in older adults with leg pain, no pain when sitting and improvement bending forward were the strongest clues to lumbar spinal stenosis. The two can occur together, so this kind of pain needs assessing.
Sources 12, 13, 14, 15, 16
A limp and the Trendelenburg signEmerging evidence
A limp from pain, where you spend less time on the sore leg, is common with arthritis and tendon pain. A Trendelenburg gait is different: the pelvis drops on the side of the swinging leg because the hip muscles on the standing side can't hold it level, from weakness or hip pain. In 24 women with outer hip pain, a positive Trendelenburg sign picked out a torn gluteus medius tendon about three times in four.
Sources 17, 18, 8
A stress fracture after a jump in walkingStrong evidence
Stress fractures aren't only a runner's problem: the American Academy of Orthopaedic Surgeons says people who aren't athletes can get one by walking much more than usual, with aching at night and a limp. A stress fracture of the neck of the thigh bone causes groin pain with exercise, and a delay in diagnosis makes it more likely to shift out of place, which is why it needs checking the same day.
Sources 19, 20
When a scan or test helpsStrong evidence
Hip arthritis: NICE advises against routine imaging unless the symptoms aren't typical. A suspected stress fracture: an X-ray first, then an MRI scan. Outer hip pain is diagnosed with simple clinical tests, and in 65 people with outer hip pain, 20 had tendon changes on MRI but negative clinical tests, so a scan report has to match the story.
Suspected narrowed arteries: comparing the blood pressure at the ankle and the arm, called the ankle brachial pressure index (ABPI). Stenosis: scans aren't usually needed at first, an NHS spinal service says.
Sources 2, 20, 21, 22, 23, 12, 16
How it usually goesEmerging evidence
Arthritis "doesn't necessarily get any worse over time and it can sometimes gradually improve", the NHS says, and NICE says pain may rise when you start exercising and settle as you carry on. Outer hip pain "can often take 6 to 12 months of rehabilitation to settle", NHS inform says; in the LEAP trial, about half of those who waited and saw had improved by a year, against more than three-quarters with education and exercise.
With narrowed arteries, 75% of people stay the same or improve and 5% to 10% get worse to the point of threatening the leg, an NHS Scotland pathway says, and walking distance usually increases over 3 to 6 months of regular walking. No one can promise a date.
Sources 4, 2, 5, 24, 14, 13