Hip X-ray: why it is done, what happens and what the result can show

An X-ray passes a small, carefully controlled dose of radiation through the body onto a detector. Dense structures such as bone absorb more of the beam and appear pale, while softer tissues let more through and appear darker. That makes a plain X-ray particularly good at showing the shape and outline of bones and the spaces between them, which is why the NHS says standard X-rays are used mainly to check your bones.

A hip X-ray normally shows the ball and socket joint where the thigh bone (femur) meets the pelvis, together with the top of the thigh bone and the surrounding part of the pelvis. Sometimes pictures are taken of both hips for comparison, or from more than one direction, and sometimes the pelvis is included. The radiographer, the healthcare professional who carries out X-rays in hospital, decides the positions needed for the clinical question.

The picture shows bone and joint space well, but it shows muscles, tendons, cartilage, the labrum (the rim of tissue around the socket) and nerves poorly or not at all. When those structures are the concern, another test such as ultrasound or MRI may be needed.

The NHS says hip pain is common, especially as you get older, and can be caused by a sudden injury or a longer-lasting problem such as arthritis. It lists several possible causes, including a hip fracture after a fall or injury, sprain or strain, osteoarthritis in people over 45 whose pain is worse when walking, rheumatoid arthritis, joint infection and bursitis. An X-ray helps separate some of these.

• Injury and suspected fracture: to see whether a bone is broken or out of position after a fall or accident.

• Persistent hip or groin pain: to look for signs of joint wear such as narrowing of the joint space, or changes in the shape of the ball and socket.

• Stiffness or reduced movement: to look for arthritis or a structural problem in the joint.

• Before or after surgery: to plan a hip operation or check a hip replacement.

• Limp or leg length difference: to assess the hips and pelvis together.

The NHS gives clear advice about when not to wait for a routine X-ray. Call 999 or go to A&E if you have severe hip pain after a fall or injury, are unable to walk or put weight on your leg, or have tingling or loss of feeling in your hip or leg after an injury. The NHS also says not to drive yourself to A&E.

Ask for an urgent GP appointment or get help from NHS 111 if you have severe hip pain that started suddenly without a fall or injury, a swollen hip that feels hot, skin around the hip that has changed colour, or hip pain with feeling generally unwell and a high temperature or feeling hot, cold or shivery. These can be signs of infection or other serious problems.

For less urgent pain, the NHS suggests seeing a GP if hip pain is stopping normal activities or affecting sleep, is getting worse or keeps coming back, has not improved after 2 weeks of home treatment, or if you have hip stiffness for more than 30 minutes after waking up.

Most X-rays are carried out in hospital departments. You may be asked to remove clothing or jewellery with metal in the area being imaged, and to change into a gown. The NHS says that you should tell the healthcare professional if you are pregnant or might be pregnant, and that you can ask for a chaperone, either someone you know or a trained member of staff.

You usually lie on a table or stand against a detector. The X-ray machine is lined up with your hip, and the radiographer moves behind a screen or leaves the room, as the NHS describes. You are asked to keep very still for a few seconds while one or more X-rays are taken. For the hip, more than one picture from different angles is common. If you are in significant pain after an injury, the radiographer will adapt positions and staff will help you.

You can usually leave as soon as the X-ray has been taken. No special preparation or fasting is needed for a standard hip X-ray, unless the hospital tells you something different.

The NHS says X-rays are usually very safe and serious complications are rare. It also explains that if you have lots of X-rays, there is a very small risk that the radiation could cause cancer, and that your doctor will assess the risks before offering you an X-ray and discuss them with you. A single hip X-ray uses a small dose.

Because radiation can affect a developing baby, telling staff about a possible pregnancy matters. A hip X-ray normally involves the pelvic area, and the department can decide whether it is needed, can be delayed or whether another test is more suitable.

A radiologist or a trained reporting radiographer looks at the images and writes a report. The NHS says you should be told when you will get the results, which may be on the same day at an appointment or a few weeks later, and that a healthcare professional should explain the results and any next steps, which may include other tests.

It is also worth knowing that an X-ray is not always needed. The NHS says that, for osteoarthritis, a GP will first ask about symptoms and examine the joints, and that further tests such as X-rays or blood tests are not usually necessary but may be used to rule out other causes such as rheumatoid arthritis or a fractured bone.

A normal X-ray does not mean the hip is perfectly healthy. Early arthritis, small fractures that are not yet visible, damage to cartilage or the labrum, tendon problems and some causes of referred pain from the spine are not always seen. If symptoms persist after a normal X-ray, the next step is usually a review with a GP, physiotherapist or orthopaedic specialist, and sometimes an ultrasound or MRI scan.

An abnormal X-ray can show joint narrowing, bone spurs, a fracture, or a change in the shape of the hip. How much these changes matter depends on the symptoms, so your doctor looks at the picture and the person together. The NHS says treatment for hip pain depends on its cause and can include painkillers, exercises, physiotherapy, occupational therapy, steroid injections and referral to a specialist, with hip replacement considered if other treatments do not help.

On the NHS, a hip X-ray is usually requested by a GP, an A&E clinician or a musculoskeletal service. The NHS notes that in many areas you may be able to refer yourself to community musculoskeletal services for back or joint help without needing a GP referral, and that service can arrange imaging when it is clinically appropriate. Private providers also carry out X-rays, and the report should go to the doctor who requested it. Whichever route you use, make sure the result is shared with your GP so that someone is responsible for acting on it.