What is a hip X-ray?
A hip X-ray (or hip radiograph) is a black-and-white image produced by a special machine that sends an X-ray beam through the area of interest (the hip in this case) and then gets the images on a film to be interpreted by the radiologist. It is usually the first type of imaging done when a hip joint problem is suspected. The bones absorb the X-ray beam more than the other surrounding soft tissues and therefore they are usually easily seen and assessed on X-rays.
What will a hip X-ray show or diagnose?
Hip X-rays are readily available and can be arranged by your doctor when there is a suspected hip joint problem. They will provide the clinicians with valuable information about the condition of the joint. The main indications for a hip X-ray are:
Hip arthritis: A shoulder x-ray will assess if there is any arthritis and the degree of changes.
Normal hip X-ray
Right hip joint osteoarthritis. Note the loss of the space between the bones and the formation of bony spurs (called osteophytes)
Femoroacetabular impingement- refers to bony impaction between the femur and the hip bone during hip movement. To find out more, please see our article about femoroacetabular impingement.
To assess for a special condition called (avascular necrosis). This refers to the death of the bone cells within the upper femur due to the interruption of their blood supply.
Suspected fractures around the hip joint: When there is suspicion of any bony injury, a hip X-ray is routinely performed to assess for any fractures. It is also useful to follow up on fractures to assess for bony alignment and fracture healing.
A plain film demonstrating fracture of the left upper femur (red colour). This is called femoral neck fracture and often requires surgical fixation.
To assess the appearance following surgical treatment. An X-ray will provide useful information about the position and alignment of any metalwork or fixation devices.
An X-ray showing plate and screws fixation to a previous fracture within the upper femur (thigh) bone.
When there is suspicion of a bone problem (like bone infection or mass arising from the bone).
To assess hip replacements. X-rays are very useful for checking the position and alignment of the prosthesis.
What are the limitations of a hip X-ray?
A hip X-ray cannot assess the soft tissues adequately. Therefore, when there is suspicion of shoulder soft tissue problems like Trochanteric hip bursitis, iliopsoas bursitis/tendinosis, proximal hamstrings tendinopathy and adductor tendinosis/tear, further imaging using hip ultrasound or MRI is usually required.
Hip X-ray vs Ultrasound and MRI
Ultrasound is high-frequency sound waves produced by a special machine and can provide useful images of the tissues within the body. It is very useful to assess the soft tissues around the hip joint (particularly the tendons and the bursae) as an X-ray cannot assess these. Most importantly, ultrasound is useful in guiding injection therapy around the hip joint. Ultrasound allows for direct visualisation of the needle to ensure the medicines are injected into the targeted site. There is significant evidence that ultrasound-guided injections provide better levels of pain relief and more prolonged effects compared with injections done without imaging guidance. Performing the injection under ultrasound guidance allows for the visualisation of the adjacent structures and reduces the risk of tissue injury at the injection site. Visualisation of the deep structures inside the hip joint (like the labrum and the articular cartilage) is difficult with ultrasound.
An MRI examination uses strong magnetic fields and radio waves and produces detailed images of a particular body part. MRI is useful for assessment of the soft tissue structures deep within the joint, for example, when there is suspicion of injury to a certain cartilage-type tissue within the hip called “the labrum” or when there is suspicion of injury to the articular cartilage. MRI, however, is more expensive and requires you to stay still for 20-30 minutes inside a special machine. To find out more, please read our article about hip MRI.
Hip conditions and treatments