Diagnosing Osteoarthritis of the Hip

At NYU Langone, doctors use advanced imaging tests to diagnose osteoarthritis of the hip, a progressive condition that leads to pain, stiffness, and limited range of motion in the joint.

The hip is a ball-and-socket joint: the rounded top of the thigh bone, or femur, fits snugly into a bowl-shaped area in the lower pelvis, called the acetabulum. Both surfaces are lined with a protective material called cartilage, which provides a smooth gliding surface and helps the bones to move easily while the body is in motion. In addition, a tough ring of cartilage, called the labrum, surrounds the outside of the joint, providing a tight seal that helps keep the joint lubricated.

The onset of osteoarthritis of the hip affects everyone differently. Some people experience sharp pain in the hip during everyday activities; some notice increasing stiffness when getting out of bed in the morning. Some find that one leg feels shorter than the other, causing a slight limp.

The cause of pain and other osteoarthritis symptoms is often bone-on-bone friction that occurs as cartilage erodes. Over time, repeated contact between the bones may wear away the cartilage layer completely, leaving the joint vulnerable to permanent damage. Bony growths called bone spurs or osteophytes often develop as a result of friction in the joint. Osteophytes may get in the way of joint motion, making osteoarthritis symptoms worse.

New research suggests that not everyone experiences osteoarthritis symptoms to the same degree as a result of cartilage erosion and friction in the joint. For many people, hip pain is caused by inflammation in the membrane lining the joint, called the synovium. In a healthy hip, the synovium secretes a gel-like substance called synovial fluid that lubricates the joint and absorbs stress during movement. Pain and stiffness related to osteoarthritis have been linked to a thinning of synovial fluid, which further contributes to joint degeneration.

Osteoarthritis often affects people over age 60, whether symptoms are the result of cartilage erosion, thinning of the synovial fluid, or both. Less commonly, osteoarthritis develops in younger people as the result of an injury such as a labral tear or a condition called hip impingement syndrome that occurs when the bones of the hip joint don’t align properly. These conditions can cause cartilage damage in the hip joint and may lead to premature osteoarthritis.

Rarely, osteoarthritis of the hip develops as a result of a childhood medical condition that affects the shape of the bones in the hip and may lead to friction between bones in the joint. These conditions include Legg-Calvé-Perthes disease and childhood hip dysplasia.

Our hip specialists evaluate your symptoms from a variety of medical perspectives to confirm the presence of arthritis and determine effective ways to manage pain and improve mobility.

Medical History

Because the symptoms of osteoarthritis of the hip vary from person to person, and because arthritis symptoms may be similar to those of other medical conditions, it’s important for doctors to learn as much as possible about your specific experience. Your doctor may ask you when hip pain, stiffness, or dysfunction began, where the pain is located, what movements are most painful, and how much these symptoms interfere with your daily activities.

In addition, doctors need to know whether you have any underlying medical conditions and if they require medication, as well as whether you’ve previously had hip surgery or an injury to the hip. Our doctors can distinguish between osteoarthritis and rheumatoid arthritis of the hip, an inflammatory condition that may cause similar symptoms. These and other details help doctors determine your treatment options.

Physical Exam

Our doctors examine you to determine if any physical signs suggest osteoarthritis of the hip. They may ask you to gently move your hip in different ways, and to walk back and forth to see if joint pain is causing any changes in your gait, such as a limp. Doctors may also gently press the skin outside of the hip joint to check for tenderness or swelling.

X-rays

Doctors may recommend X-rays in order to confirm a diagnosis of osteoarthritis of the hip. X-rays create detailed images of the inside of the body and can reveal a narrowing of the cartilage layer in the hip joint. Doctors can also see if the bones in the joint are lining up properly and if any small pieces of cartilage or bone have come loose and are causing friction within the joint.

MRI Scans and Ultrasound

MRI scanning and ultrasound imaging can help doctors diagnose mild cases of osteoarthritis or identify soft tissue problems in the hip joint, such as a labral tear. A doctor may also use these tests to assess whether there is inflammation in the synovial membrane. He or she may also use ultrasound to locate pockets of fluid in the joint that aren’t visible on X-ray images.

During an ultrasound, high-frequency sound waves are used to create images of structures inside the body. This exam often takes place at the same time as a physical exam in the doctor’s office.

MRI uses magnetic fields and radio waves to produce detailed two- or three-dimensional images that allow doctors to examine the hip from a variety of angles.

Patient-Reported Outcome Score

As part of the diagnostic process, doctors at NYU Langone use a measurement called a patient-reported outcome score to assess your type of hip pain and current level of function. This method consists of a questionnaire that doctors use to obtain information about your specific symptoms: whether they prevent you from participating in everyday activities, how much symptoms affect your quality of life, and whether you’ve limited your participation in sports or exercise because of arthritis.

The results of the questionnaire help in creating a treatment plan. For example, some people may not show joint damage on an X-ray but still have chronic pain. Others feel little or no pain, even though an X-ray reveals significant cartilage erosion.

By using the patient-reported outcome tool, our arthritis experts ensure that treatment is individualized to meet your needs and not solely based on diagnostic tests. Following these scores over time can help you and your doctor identify how much arthritis symptoms are affecting your life.