The hip joint: the commonest cause from mid-lifeStrong evidence
The NHS links hip pain that is worse when you walk, with stiffness after moving, in people over 45, to osteoarthritis, and NHS inform says hip osteoarthritis is felt in or around the hip, the groin, the buttock or the front of the thigh, and is worse with activity, stairs, getting up from a chair and getting out of a car. Arthritis UK says hip problems are felt in the groin, down the front of the leg and in the knee. In 51 people whose pain was confirmed to come from the hip joint, 55% felt it in the groin, 57% in the thigh and 71% in the buttock.
NICE diagnoses osteoarthritis without a scan in people aged 45 or over whose joint pain comes with activity and whose morning stiffness lasts 30 minutes or less.
Sources 1, 2, 3, 4, 5
Muscles, tendons and the hip's shape in active peopleEmerging evidence
An international agreement on groin pain in athletes, made in Doha, sorts it into four types (adductor-related, iliopsoas-related, inguinal-related and pubic-related) plus groin pain from the hip joint and other causes. The patterns in this guide's map come from our groin pain guide: inner thigh pain worse squeezing the knees together, front-of-hip pain lifting the knee, pain just above the groin crease with sit-ups or coughing, and pain on the pubic bone in kicking sports.
Hip impingement is diagnosed only when symptoms, examination findings and imaging agree, another international agreement says, and it's treated with physiotherapy, rehabilitation or surgery; our hip impingement guide describes a groin pinch with deep bending, sitting low or getting out of a car. The evidence on these causes comes mostly from athletes.
Sources 6, 7, 8
HerniasStrong evidence
An inguinal hernia is a lump where your leg joins your tummy that may get bigger when you cough or strain and smaller when you lie down, sometimes with a heavy, dragging feeling in the leg; an international guideline lists being male, older age and a family history among the risks. A femoral hernia is a small, grape-sized lump at the top of the thigh, with aching that comes and goes and discomfort when you walk; it mainly happens in women over 50 and needs treating in hospital, because it can become strangulated, which is an emergency.
The NHS says to get help from NHS 111 for a hernia that becomes painful, or comes with being sick, constipation, a high temperature or sudden confusion, and to call 999 for a femoral hernia with very bad tummy pain, being sick or not being able to poo or fart.
Sources 9, 10, 11, 12
Bone stress and broken bonesEmerging evidence
Stress fractures of the neck of the thigh bone (the femoral neck) make up 3% of sport-related stress fractures, most often from marathon and long-distance running, and exercise-related groin pain is the commonest symptom; delays in diagnosis are common and make it more likely the break moves out of place, which makes the outcome worse. Stress fractures are seen in athletes and military recruits, typically after a sudden increase in exercise, and those on the side of the femoral neck that is pulled apart as you load it (the tension side) are high risk, a review says. The evidence comes from runners and recruits, so applying it to people who have suddenly walked much more is our extension.
In people taking a bisphosphonate bone medicine, a dull or aching thigh, hip or groin pain can come weeks to months before an unusual break of the thigh bone, the UK medicines regulator (MHRA) says. After a fall in later life, a broken hip causes pain in the hip, upper leg or groin, and NICE advises a magnetic resonance imaging (MRI) scan if a break is still suspected after a normal X-ray.
Sources 13, 14, 15, 16, 17, 18
PregnancyStrong evidence
Pelvic girdle pain affects up to 1 in 5 pregnant women, the NHS says: pain over the pubic bone at the front, across the lower back, in the area between the vagina and the anus, or spreading to the thighs, worse walking, on stairs, standing on one leg, turning over in bed and moving your legs apart. It isn't harmful to your baby, and most women with it can have a vaginal birth. A sharp cramp low on one side of the tummy can be ligament pain.
Sources 19, 20
Children and teenagersStrong evidence
In a child or teenager, groin, hip, thigh or knee pain with a limp can be irritable hip, Perthes disease or a slipped growth plate at the top of the thigh bone (slipped upper femoral epiphysis). The NHS says a limp with no obvious cause should always be checked, and sudden hip, knee or thigh pain, not being able to put weight on the leg, or a limp with a high temperature and feeling unwell is a 999 or A&E matter.
Sources 21, 22
Causes that aren't the hip or the groin musclesStrong evidence
A kidney stone causes severe pain starting in the side of the tummy or the lower back that can spread to the groin, the testicles or the vagina. Testicle problems can cause groin pain, and sudden, severe testicle pain is an emergency. Swollen glands in the groin usually follow an infection. Narrowed leg arteries cause an ache in the buttock, thigh or calf when you walk that goes after a few minutes' rest.
A hot, swollen hip with a high temperature can be a joint infection, and severe pelvic pain with feeling faint, shoulder tip pain or heavy bleeding from the vagina is a 999 call. Rarely, bone pain that is constant or worse at night comes from a bone tumour.
Sources 23, 24, 25, 26, 1, 27, 28, 29
Tests and scansEmerging evidence
Many causes don't need a scan at first. NICE diagnoses osteoarthritis from the symptoms in people over 45, an inguinal hernia can usually be confirmed by an examination, and hip impingement needs symptoms, examination findings and imaging together. A suspected stress fracture of the hip needs an urgent X-ray and then an MRI scan, and after a fall in later life, NICE advises an MRI if a hip fracture is still suspected despite a normal X-ray. A child or teenager with a limp needs to be seen the same day, and our slipped growth plate guide asks for a hip X-ray.
Sources 5, 7, 11, 13, 18, 21
How it usually goesEmerging evidence
Osteoarthritis comes and goes, doesn't necessarily get worse and can sometimes gradually improve, the NHS says, and exercise eases the pain a little. Long-standing adductor pain in athletes responded to 8 to 12 weeks of active training. Most men with a hernia that caused few symptoms did well waiting, though about a quarter had surgery within a few years.
Femoral neck stress fractures found early do well, and in a review of 103 people from case reports, 71% of those followed long term returned to their full activity; displaced breaks do much worse. Pelvic girdle pain tends not to get completely better until the baby is born, but treatment can ease it. No one can promise a timescale.
Sources 30, 31, 8, 12, 13, 32, 19