Diagnosing arthritis in the hip typically starts with a physical exam and X-rays, though blood tests and advanced imaging may be needed to pinpoint the exact type and severity. Because hip pain can come from several different sources, including conditions that mimic arthritis, the diagnostic process often involves ruling out other possibilities before confirming a diagnosis.
What Your Doctor Looks for First
The initial evaluation focuses on your symptoms, your age, and how your hip moves. Hip osteoarthritis, the most common form, follows a recognizable pattern: pain deep in the groin or front of the thigh that worsens with activity and improves with rest. Morning stiffness is common but typically fades within 30 minutes or less. If your stiffness lasts longer than an hour, especially if it improves with movement rather than rest, that raises suspicion for inflammatory arthritis like rheumatoid arthritis or ankylosing spondylitis instead.
The American College of Rheumatology established clinical criteria that can classify hip osteoarthritis even without imaging. A person over 50 with hip pain is likely to have osteoarthritis if they also have at least 15 degrees of internal rotation, pain when the hip is rotated inward, and morning stiffness lasting under 60 minutes. If internal rotation is more restricted (less than 15 degrees), the diagnosis can still be made using blood inflammation markers or by checking whether hip flexion is limited. These criteria catch about 86% of true cases.
The Physical Exam
Your doctor will watch you walk, then move your hip through its full range of motion while you lie on the exam table. Two key maneuvers come up frequently. The FADIR test involves bending your hip, then rotating and pulling your knee inward across your body. This test is highly sensitive for detecting problems inside the joint, meaning it rarely misses an issue when one exists. The FABER test moves your hip into a figure-four position, with your ankle resting on the opposite knee, and then presses the bent knee toward the table. This test is better at confirming specific conditions like labral tears when it reproduces your pain.
Range of motion itself is diagnostic. Internal rotation is usually the first movement to become restricted in hip arthritis. If turning your foot inward while your hip is bent causes a familiar deep ache, or if the movement simply doesn’t go as far as it should, that’s a strong signal the joint surface is involved.
Where Your Pain Is Matters
One of the trickiest parts of diagnosing hip arthritis is that “hip pain” means different things to different people. True hip joint arthritis usually produces pain in the groin, the front of the thigh, or sometimes the buttock. Many people point to the outside of their hip, but pain on the outer side is more likely to be greater trochanteric pain syndrome, a condition involving the tendons and soft tissue on the bony prominence you can feel on the side of your thigh.
Greater trochanteric pain syndrome hurts most when you lie on the affected side, press directly on the outer hip, sit with your legs crossed, or stand on one leg. It often coexists with hip or knee osteoarthritis and low back problems, which can make sorting out the true pain source difficult. If your pain is mainly lateral (on the outside), your doctor may focus on these soft tissue structures before investigating the joint itself.
Other conditions that can feel like hip arthritis include pinching of the hip bones against each other during movement (femoroacetabular impingement), referred pain from the lower back, and, more rarely, infection or bone disease. Your doctor considers all of these during the initial workup.
X-Rays and What They Show
Standard X-rays are the first imaging step for suspected hip arthritis. Doctors use the Kellgren-Lawrence grading scale to rate the severity of osteoarthritis on a scale from 0 to 4:
- Grade 0: Normal joint, no narrowing or bone changes.
- Grade 1: Questionable narrowing of the joint space, possible small bone spurs forming at the edges.
- Grade 2: Clear bone spurs visible, with possible early narrowing of the space between the bones.
- Grade 3: Moderate bone spurs, definite joint space narrowing, some hardening of the bone underneath the cartilage, and possible changes in the shape of the bone.
- Grade 4: Large bone spurs, severe loss of joint space, significant bone hardening, and visible deformity of the femoral head (the ball of the hip joint).
The hallmark findings are narrowing of the space where cartilage should be, bone spurs at the joint margins, hardening of the bone just beneath the cartilage surface, and small cyst-like pockets in the bone near the joint. A grade 2 or higher generally confirms the diagnosis when paired with matching symptoms. One important caveat: X-ray findings don’t always match how much pain you feel. Some people with severe-looking X-rays have mild symptoms, and others with early radiographic changes have significant pain.
When MRI or Other Imaging Is Needed
X-rays are sufficient for most straightforward cases of hip osteoarthritis. MRI becomes useful in specific situations where the diagnosis is uncertain or something more complex may be happening. Your doctor is more likely to order an MRI if you have mechanical symptoms like catching or locking in the hip, a family history of inflammatory arthritis, prolonged morning stiffness suggesting an inflammatory cause, risk factors for bone loss or avascular necrosis (where the bone loses its blood supply), a history of significant trauma, or signs of possible infection such as fever and a swollen, red joint.
MRI can detect cartilage damage, labral tears, early bone marrow changes, and soft tissue problems that X-rays miss entirely. This makes it particularly valuable in younger patients whose X-rays may look normal despite significant joint damage, or when the pain pattern doesn’t fit a typical osteoarthritis picture.
Blood Tests and What They Rule Out
Blood work isn’t needed to diagnose osteoarthritis itself, since osteoarthritis doesn’t produce distinctive blood markers. But blood tests play an important role in ruling out other types of arthritis that can affect the hip.
If inflammatory arthritis is suspected, your doctor will check markers of inflammation like the erythrocyte sedimentation rate (a measure of how quickly red blood cells settle in a tube, which rises when inflammation is present). For rheumatoid arthritis specifically, two antibody tests are key: rheumatoid factor and anti-citrullinated peptide antibodies. The second test is more specific to rheumatoid arthritis and also correlates with more aggressive joint damage. Rheumatoid factor alone can be elevated in many other conditions, from chronic infections to other autoimmune diseases, so a positive result doesn’t automatically mean rheumatoid arthritis.
For ankylosing spondylitis, a form of inflammatory arthritis that commonly affects the spine and hips, a genetic marker called HLA-B27 can support the diagnosis when the clinical picture fits. Having the gene doesn’t guarantee you’ll develop the condition, but its absence makes ankylosing spondylitis much less likely.
Diagnostic Injections
When the source of hip pain remains unclear after examination and imaging, your doctor may suggest a diagnostic injection. This involves placing a numbing agent directly into the hip joint under imaging guidance. The logic is simple: if the injection temporarily eliminates your pain, the joint itself is the problem. If the pain persists, the source is likely somewhere else, such as the spine, surrounding tendons, or a nearby nerve.
While this approach makes intuitive sense, the research supporting it is limited. A meta-analysis of available studies found that when the injection fails to relieve pain, that result reliably predicts that the hip joint isn’t the pain source. But the overall evidence quality was too low to make strong recommendations about the technique. In practice, diagnostic injections remain a useful tool when the picture is genuinely ambiguous, particularly before considering surgery.
Putting the Diagnosis Together
No single test definitively diagnoses hip arthritis in every case. Instead, your doctor builds the picture from several pieces: your symptom pattern (groin pain, activity-related worsening, brief morning stiffness), physical exam findings (reduced internal rotation, pain with specific maneuvers), X-ray results (joint space narrowing, bone spurs), and blood work that rules out inflammatory causes. For most people over 50 with a classic presentation, the diagnosis is straightforward and can often be made in a single office visit with an X-ray. Younger patients, people with atypical pain patterns, or those with risk factors for inflammatory conditions may need the fuller workup including MRI and lab testing before the picture becomes clear.