Femoroacetabular impingement (FAI) is a difference in hip-joint shape that can irritate the labrum and cause deep hip and groin pain in active adults. But here's the catch: many people have the FAI shape on a scan and no symptoms at all. So "do I have FAI?" is really two questions — does the shape exist, and is it actually causing your pain?
This guide covers the typical symptoms and how they differ from other hip problems, so you know whether a specialist assessment is worth it.
The typical symptoms of FAI
The most common symptom pattern in symptomatic FAI is a combination of the following — usually felt on one side, often developing gradually rather than from a single injury.
- Deep groin pain, often shown with the "C-sign" — cupping the hand around the side of the hip with the thumb in the groin and the fingers wrapping around the outer edge.
- Pain with prolonged sitting, getting in and out of a low car, or sitting in a low chair or deep squat.
- Catching, clicking or pinching inside the joint — more so when a labral tear is also present.
- Stiffness and a feeling the hip "won't go" into deep ranges, particularly into internal rotation or deep flexion.
- Pain with twisting and pivoting — common in runners, footballers, dancers and martial artists, where rotation and deep flexion both load the same tissues.
What FAI does NOT usually feel like
Matching the symptom pattern to the structure is the whole point. Two common patterns get mislabelled as FAI when they aren't:
Outer-hip pain over the bony point
This is more likely gluteal tendinopathy (the real driver behind most "hip bursitis") than FAI. Pain is on the outside of the hip, worse lying on it, worse with single-leg loading — a different region and a different problem from intra-articular impingement.
→ Hip bursitis: symptoms and the real causes →Pain that spreads, with nerve symptoms
Pain that spreads rather than staying local, or comes with pins and needles, numbness, or pain that runs down the leg, is more likely referred from the lower back. FAI itself is a joint problem — it doesn't usually cause nerve-type symptoms.
→ Hip pain causes and the role of the spine →Why a scan alone doesn't diagnose FAI
Cam and pincer shapes (the two morphology types behind FAI) and incidental labral changes are common in pain-free people. Studies repeatedly show a meaningful slice of asymptomatic adults have FAI-shaped hips on imaging — and a slice of those also have labral changes that look like tears on MRI.
That's why imaging is interpreted alongside the examination, never on its own. A "labral tear on MRI" doesn't automatically explain your pain — and it doesn't automatically mean surgery. The clinical picture — your story, your movement patterns, the impingement tests, the response to loading — matters as much as the scan.
The shape isn't the symptom. Many active adults live with FAI-shaped hips their whole lives without ever knowing. The decision about whether to treat — and how — depends on whether the shape is actually driving the pain, not on the scan alone.
Simple signs it's worth getting assessed
A specialist assessment is worth considering when several of the following apply:
- Deep groin pain in an active 30–55-year-old.
- Sitting and deep flexion reliably make it worse — long drives, low chairs, deep squats.
- Catching, clicking or a sense of the joint "getting stuck" during movement.
- It hasn't settled with generic physiotherapy, or keeps returning after short-term improvement.
Red flag: hot, swollen hip with fever
A hot, swollen, feverish hip needs urgent medical assessment today — not physiotherapy. This can indicate infection in the joint (septic arthritis) and requires prompt treatment.
When to see a specialist
If these symptoms sound familiar and aren't improving, a specialist can confirm whether FAI is genuinely driving your pain — and whether it can settle without surgery. The full pillar page on hip impingement, FAI and labral tears covers the conservative rehabilitation approach in detail.
Want clarity on whether FAI is the cause?
John Gravenall offers specialist hip and groin assessments in London, the Midlands, and online.
Book a specialist hip assessment →Frequently Asked Questions
What does hip impingement feel like?
Deep groin pain (often shown with the C-sign — cupping the hand around the side of the hip), worse with prolonged sitting, deep squatting, and twisting or pivoting. Some people feel catching, clicking, or a sense of something getting stuck.
Can you have FAI without symptoms?
Yes. The cam and pincer shapes that define FAI are common on scans in people with no hip pain at all. That's why a scan alone doesn't diagnose FAI as the cause of symptoms — examination and clinical reasoning matter as much as imaging.
How is FAI diagnosed?
Through a combination of history, movement and impingement tests in a clinical exam, with X-ray and (sometimes) MRI interpreted alongside the clinical picture — not on their own.
Does FAI go away?
The bone shape itself doesn't change, but symptoms can settle in many people with the right conservative rehabilitation — load management, hip control work, and targeted strengthening. Surgery is one option when conservative care hasn't helped and symptoms are clear and persistent.