Hip Osteoarthritis: Symptoms, Signs and Diagnosis

What hip osteoarthritis actually feels like, where the pain comes from, what a surgeon finds on examination, and what your X-rays mean — explained clearly for patients and their families.

Hip osteoarthritis is the second most common form of osteoarthritis after the knee, and one of the leading causes of pain and disability in adults over the age of 50.¹ Despite how prevalent it is, patients frequently arrive in clinic having lived with significant symptoms for years, unsure whether what they are experiencing is truly their hip, uncertain about where to seek help, and often surprised to learn how much can be done — both before and after a decision about surgery.

This article explains what hip osteoarthritis feels like from a patient’s perspective, what a surgeon looks for on examination, and what your X-rays actually mean.

Where does hip osteoarthritis hurt?

The most characteristic symptom of hip osteoarthritis is groin pain — a deep, aching discomfort felt in the front of the hip crease, which may radiate down the inner thigh towards the knee.^1,2 Many patients are surprised by this because they expect hip pain to be felt on the outer side of the hip or buttock. In fact pain felt directly over the lateral hip — the bony prominence you can feel on the outer thigh — more commonly comes from the bursa or tendons around the hip, not from the joint itself.

That said, hip osteoarthritis can also present as:^2,3

• Anterior thigh pain — aching in the front of the thigh, sometimes confused with muscle pain
• Knee pain — referred pain from the hip can travel all the way to the knee via the obturator nerve, and it is not uncommon for patients to present to clinic convinced their knee is the problem when it is actually their hip
• Buttock pain — deep posterior discomfort, sometimes confused with sciatica or lumbar spine disease
• Lateral hip pain — less typical, but can occur, particularly in more advanced disease

This variability in pain location is one reason why hip osteoarthritis is sometimes misdiagnosed or delayed. If you have been told you have knee pain, a back problem, or a muscle strain and treatment has not helped, it is worth asking whether your hip has been properly assessed.

What does the pain feel like?

The pain of hip osteoarthritis tends to have a fairly characteristic pattern, though it varies between patients and changes as the disease progresses.^2,4

In the early stages, pain is typically:

• Activity-related — brought on by walking, climbing stairs, getting in and out of a car, or putting on shoes and socks
• Relieved by rest — sitting down or lying still eases it
• Associated with start-up stiffness — a familiar stiffness and aching after sitting for a period that eases after a few minutes of walking, sometimes called the “gelling phenomenon”
• Worse at the end of the day after activity

As the disease progresses, the pattern changes:

• Pain occurs with less activity — short walks that were previously manageable become difficult
• Rest pain develops — discomfort that is present even when sitting still
• Night pain emerges — waking in the night with hip discomfort, often when turning over in bed, is a sign of more advanced disease and a significant indicator that the condition is having a major impact on quality of life
• Morning stiffness may increase, though in osteoarthritis it typically lasts less than 30 minutes — stiffness lasting longer than this should raise the possibility of inflammatory arthritis⁵

What else might you notice?

Beyond pain, patients with hip osteoarthritis commonly report:^2,3

• Reduced range of movement — difficulty crossing legs, cutting toenails, getting in and out of a low car, or performing rotational movements
• A limp — an antalgic gait (limping to offload the painful hip) or, in more advanced cases, a Trendelenburg gait caused by weakness of the hip abductor muscles
• Leg length discrepancy — in severe hip OA, the femoral head can migrate upward within the joint, causing a functional shortening of the affected leg
• Clicking or clunking — though this is less specific and can occur in normal hips
• Giving way — particularly on uneven ground, related to muscle weakness and loss of proprioception
• Impact on daily activities — difficulty with stairs, prolonged walking, housework, sport, and in some patients, basic self-care

What does a surgeon find on examination?

When a surgeon or clinician examines your hip, they are looking for a combination of findings that together build a picture of how your joint is functioning and how severe the disease is likely to be. The examination typically takes place with you lying on a couch and involves careful, systematic assessment of movement and strength.

The findings most strongly associated with hip osteoarthritis on examination are:⁶

• Reduced and painful internal rotation — internal rotation (turning the foot inward with the knee bent) is consistently the first movement to be lost in hip OA and is highly sensitive for the diagnosis. Reduced internal rotation has a positive likelihood ratio of 3.2 for radiographic OA⁶
• Reduced hip adduction — bringing the leg across the midline; a positive likelihood ratio of 4.2⁶
• Groin pain on passive abduction or adduction — pain reproduced by moving the leg outward or inward has a positive likelihood ratio of 5.7⁶
• Hip abductor weakness — weakness of the gluteal muscles, tested by resisted abduction or the Trendelenburg test, has a positive likelihood ratio of 4.5⁶
• Posterior hip pain on squatting — the most specific single finding, with a positive likelihood ratio of 6.1⁶
• An antalgic or Trendelenburg gait — observed as you walk into the consulting room, before any formal examination begins
• Fixed flexion deformity — assessed using the Thomas test; the inability to fully straighten the hip indicates contracture of the hip flexors, a feature of more advanced disease

A finding with a high positive likelihood ratio means that when it is present, it substantially increases the probability that osteoarthritis is the diagnosis. These examination findings are therefore not just routine — they are diagnostically meaningful.

What do your X-rays show?

Plain X-rays of the hip remain the first-line investigation for suspected hip osteoarthritis and are usually all that is needed to confirm the diagnosis and plan treatment.⁵ A standard assessment includes an anteroposterior (AP) view of the pelvis — showing both hips together for comparison — and a lateral view of the affected hip.

The radiographic features of hip osteoarthritis are:^7,8

• Joint space narrowing — the most important finding. The apparent “space” between the femoral head and the acetabulum on X-ray represents the cartilage. As it is lost, this space narrows. Superior joint space narrowing (loss at the top of the joint) is the most common pattern in hip OA
• Osteophytes — bony spurs growing around the margins of the joint, visible as irregular projections at the edges of the femoral head and acetabulum
• Subchondral sclerosis — increased whiteness (density) in the bone immediately beneath where the cartilage has been lost, as the bone attempts to compensate for the absent cushioning
• Subchondral cysts — small fluid-filled cavities within the bone near the joint surface
• Femoral head deformity — in more advanced disease, the femoral head itself loses its spherical shape and may migrate superolaterally (upward and outward) within the socket

These features are graded using the Kellgren-Lawrence (KL) classification, the most widely used system in clinical practice:^8,9

• Grade 0 — no radiographic features of OA
• Grade 1 — doubtful: possible joint space narrowing with subtle osteophyte formation
• Grade 2 — mild: definite joint space narrowing with definite osteophytes and slight sclerosis
• Grade 3 — moderate: marked joint space narrowing, multiple osteophytes, sclerosis, cyst formation, and early femoral head deformity
• Grade 4 — severe: near-complete or complete loss of joint space, large osteophytes, gross deformity of the femoral head and acetabulum

Established, clinically significant OA is generally defined as KL grade 2 or above. However — and this is important — the grade of your X-ray does not determine whether you need surgery. Surgeons operate on patients, not X-rays. A grade 4 X-ray in a patient who is coping well and has not tried conservative measures is not an automatic indication for surgery. A grade 2 X-ray in a patient whose quality of life is severely affected and who has exhausted all non-surgical options may well be.

When might further imaging be needed?

In most cases, X-rays are all that is required. However, MRI or CT scanning may be requested in specific circumstances:

• MRI — if the diagnosis is uncertain, if inflammatory arthritis is suspected, if there is concern about avascular necrosis (bone death due to loss of blood supply), or if soft tissue pathology such as a labral tear needs assessment
• CT — primarily used for surgical planning, particularly in complex or revision cases, to assess bone stock and anatomy in three dimensions
• Bone scan or SPECT-CT — occasionally used when the source of pain is genuinely unclear and multiple joints or regions are involved

How is hip OA distinguished from other causes of hip pain?

Not all hip pain is osteoarthritis. The most important conditions to consider in the differential diagnosis are:^3,5

• Greater trochanteric pain syndrome (GTPS) — formerly called trochanteric bursitis, this presents as lateral hip pain that is point tender over the greater trochanter. It is often confused with hip OA but is a distinct condition affecting the tendons and bursa on the outer hip
• Lumbar spine disease — L3/4 nerve root pathology can refer pain to the groin and anterior thigh, mimicking hip OA. The “hip-spine syndrome” — concurrent hip and spine disease — is common and can make diagnosis challenging
• Inflammatory arthritis — rheumatoid arthritis, psoriatic arthritis, and reactive arthritis can all affect the hip. Features suggesting inflammatory arthritis include bilateral joint involvement, prolonged morning stiffness (over 30 minutes), constitutional symptoms, and elevated inflammatory markers (CRP, ESR)
• Avascular necrosis (AVN) — death of bone tissue due to disrupted blood supply, associated with steroid use, alcohol excess, sickle cell disease, and previous hip fracture. Can mimic OA on early X-rays but has a distinct appearance and often more rapid progression
• Femoroacetabular impingement (FAI) — abnormal contact between the femoral head and acetabulum, typically presenting in younger patients with activity-related groin pain and restricted internal rotation
• Referred pain from the knee or spine — pain that seems to come from the hip but originates elsewhere

An experienced clinician can usually distinguish these conditions on the basis of history and examination, with targeted investigations where needed. Getting the diagnosis right is the essential first step — because the treatment for each of these conditions is different.