Hip Osteoarthritis: Symptoms, Signs and Diagnosis

Part of The Joint Replacement Guide — Phase 1: Understanding Your Condition · Article 2 of 42 · Hip

Key Points

  • Hip osteoarthritis classically causes pain in the groin, not just the outer hip or buttock.
  • Pain is often felt in, or even only in, the thigh or knee — a well-known source of confusion.
  • Loss of internal rotation is usually the earliest and most reliable examination finding.
  • X-rays confirm the diagnosis, but the severity seen on X-ray does not always match how much pain someone is in.
  • Diagnosis and treatment decisions are based on your symptoms and function, not the X-ray alone.

Typical Symptoms of Hip Osteoarthritis

The hallmark symptom of hip OA is pain in the groin — often described as a deep, aching pain rather than a sharp one. This is one of the most useful ways doctors distinguish true hip joint pain from pain arising from other structures around the hip, such as the outer hip (more often bursitis or tendinopathy) or the lower back.

Hip pain frequently refers elsewhere. Because of shared nerve pathways (particularly the obturator nerve), pain from the hip joint is often felt in the front of the thigh or, confusingly, in the knee — sometimes with little or no pain felt in the hip itself. This is a well-recognised trap: a patient presenting with knee pain and an unremarkable knee examination should always have their hip examined too.

Other common features include:

  • Stiffness after rest, typically easing within 30 minutes of movement — a shorter duration than is typical of inflammatory arthritis.
  • Reduced range of movement, particularly noticeable when putting on socks or shoes, cutting toenails, or getting in and out of a car.
  • A limp, particularly after walking further distances.
  • Night pain and disturbed sleep in more advanced disease.
  • A sensation of the hip “catching” or feeling unstable, though true instability is uncommon in straightforward OA.

How We Examine the Hip

Examination starts before you’re even on the couch. We watch you walk, looking for an antalgic gait (a shortened stance phase on the painful side, as you spend less time weight-bearing through it) or a Trendelenburg gait, where the pelvis dips on the opposite side during walking because the hip abductor muscles aren’t controlling it effectively.

On the couch, we assess range of movement in all directions. Internal rotation is usually lost first and most severely in hip OA, and is often the single most sensitive examination finding — even before flexion or abduction become noticeably restricted. We also check for muscle wasting, particularly of the gluteal muscles, assess leg length, and perform specific tests to help rule out other causes of groin or hip pain, such as labral tears or femoroacetabular impingement.

X-rays and Imaging

An X-ray remains the standard first-line investigation for suspected hip OA — typically an AP view of the pelvis and a lateral view of the affected hip. The features we look for are:

  • Joint space narrowing — reflecting cartilage loss, usually most marked superiorly or superolaterally in the hip.
  • Osteophytes — small bony spurs at the joint margins.
  • Subchondral sclerosis — thickening and increased density of the bone just beneath the joint surface.
  • Subchondral cysts — fluid-filled cavities in the bone adjacent to the joint.

These findings are often graded using the Kellgren-Lawrence system, from grade 0 (normal) to grade 4 (severe, with significant joint space loss and large osteophytes). It is important to understand, however, that X-ray severity and symptom severity often don’t line up neatly — some people with quite advanced changes on X-ray have relatively mild symptoms, and vice versa. This is why treatment decisions, including whether or when to consider surgery, are based primarily on your pain, function and quality of life rather than the X-ray appearance alone.

In More Depth

Groin pain in adults isn’t always hip OA, and part of a thorough assessment is making sure we’re not missing something else. Younger patients with groin pain, particularly with catching or clicking sensations, may have a labral tear or femoroacetabular impingement (FAI) rather than established OA — conditions that can sometimes be treated with hip arthroscopy rather than replacement. Groin pain can also arise from inguinal hernia, adductor tendinopathy, or referred pain from the lumbar spine, all of which are considered as part of the assessment.

Where the diagnosis is unclear from history, examination and X-ray, an MRI scan can be useful — it shows cartilage, labrum, and soft tissues in more detail than an X-ray, and can help distinguish OA from these other causes, or identify early OA changes not yet visible on X-ray. It is worth noting, too, that some people have underlying hip dysplasia (a shallower-than-normal hip socket) which predisposed them to developing OA earlier than would otherwise be expected — this is sometimes only recognised when the X-ray is reviewed carefully at the time OA is diagnosed.

This article is general information and does not replace individual clinical advice. If you are concerned about your symptoms, please speak to your GP or a specialist.

Sources

  • NICE guideline NG226 — Osteoarthritis in over 16s: diagnosis and management (2022)
  • British Orthopaedic Association / British Hip Society patient resources
  • Royal College of Radiologists — imaging guidance for suspected osteoarthritis
  • Versus Arthritis — patient information on hip osteoarthritis

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