Femoroacetabular Impingement (FAI): Symptoms, Diagnosis, Treatment & Recovery

What Is Femoroacetabular Impingement (FAI)?

Femoroacetabular impingement is a mismatch between the ball of the hip (femoral head/neck) and the socket (acetabulum) that causes abnormal contact in certain positions, especially flexion and rotation. Over time, this can irritate the labrum and damage cartilage at the chondrolabral junction.

• Cam FAI: extra bone at the femoral head–neck junction (reduced offset) jams the labrum and cartilage in flexion/rotation.
• Pincer FAI: socket over-coverage or retroversion pinches the labrum on the rim.
• Mixed FAI: features of both cam and pincer morphology (common).

Common Symptoms

• Groin pain (C-sign), sometimes felt at the lateral hip or buttock.
• Clicking, catching, or locking, especially with twisting or rising from deep chairs.
• Stiffness or reduced internal rotation and flexion; difficulty with socks/shoes.
• Worse with sitting, squats, hills, sprinting, or change of direction.
• Occasional night pain when rolling or after heavy training loads.

Why FAI Happens — Mechanics & Risk Factors

• Bone shape: cam or pincer morphology from growth/adolescence or activity-related adaptations.
• Repetitive loading: field/court sports, dance, hockey, AFL, football, powerlifting, CrossFit.
• Hip instability or dysplasia: altered coverage changes load on the labrum and cartilage.
• Femoral/acetabular version differences: torsional alignment can amplify impingement.
• Previous injury or childhood hip conditions (e.g., SCFE, Perthes).

How We Diagnose FAI

We combine a detailed history, targeted examination, and imaging to confirm the diagnosis and determine whether labral tears or cartilage injury are present.

Clinical assessment

• Special tests: FADIR (impingement), FABER, scour; evaluation for instability or dysplasia features.
• Functional patterns: gait, single-leg squat, lumbopelvic control, sport-specific movements.
• Range & strength: focus on internal rotation, flexion, and deep rotator/gluteal function.

Imaging

• X-rays: pelvis and dedicated hip views for cam (alpha angle), pincer (crossover sign), version, and joint space.
• MRI or MR arthrogram: assesses labrum, chondrolabral junction, cartilage, and synovitis.
• CT (selected cases): 3D assessment of bone morphology for precise surgical planning.
• Diagnostic injection: image-guided anaesthetic to confirm the hip as the pain source.

Non-Operative Treatment

Many patients with FAI improve with a structured program aimed at pain reduction, hip–pelvic control, and graded exposure to provocative positions. We partner with our physiotherapy team to deliver a criteria-based plan.

1) Education & load management

• Reduce deep flexion, end-range rotation, and combined squat–twist movements initially.
• Adjust training volume and intensity; use cross-training (bike/pool) during flares.
• Improve sitting hygiene: frequent breaks, seat height optimisation, hip-friendly posture.

2) Physiotherapy & exercise therapy

• Gluteal strengthening and deep rotator activation to improve femoral head control.
• Mobility focused on safe ranges that do not provoke impingement.
• Progressive loading towards running, agility, and sport-specific drills with clear milestones.

3) Medications & injections

• Short courses of anti-inflammatory medication when appropriate.
• Image-guided corticosteroid injections can settle synovitis to facilitate rehabilitation.
• Platelet-Rich Plasma (PRP) may be considered in selected cases after discussion of evidence and goals.

Timeline: Many patients notice improvement within 6–12 weeks with consistent rehab and load modification. Persistent mechanical symptoms or failure to progress may prompt a discussion of surgery.

When Is Surgery Considered?

Hip arthroscopy is considered when symptoms remain limiting despite best non-operative care or when imaging demonstrates a mechanical conflict unlikely to settle without correction.

Hip Arthroscopy for FAI

• Cam osteoplasty: reshaping the femoral head–neck junction to restore offset and clearance.
• Pincer rim trimming: reducing over-coverage and protecting the labrum.
• Labral repair or reconstruction: restoring the suction seal and joint stability.
• Chondral procedures: stabilisation of flaps; selected marrow stimulation for focal full-thickness defects.
• Capsular closure/plication: restores stability, especially in laxity or borderline dysplasia.

Risks & considerations

• Infection, bleeding, clots (rare), temporary nerve irritation, stiffness.
• Persistent symptoms if advanced cartilage wear is present or if instability is unaddressed.
• Need for further surgery if morphology is not fully corrected or disease progresses.

More detail: Hip Arthroscopy (Keyhole Surgery).

Recovery & Rehabilitation

Rehabilitation is tailored to the procedures performed and your goals:

1. Week 0–2: protected weight-bearing as advised; swelling control; gentle range; isometrics.
2. Week 3–6: progress weight-bearing; stationary bike and pool; restore gait and pelvic control.
3. Week 6–12: strengthening (gluteals, deep rotators, core), proprioception; begin light jogging if criteria met.
4. Month 3–6: sport-specific change-of-direction, acceleration/deceleration; staged return to training and competition.

Desk roles often resume within 1–2 weeks with ergonomic adjustments; manual work and pivoting sports require a longer, criteria-based progression.

Outcomes: What to Expect

With appropriate patient selection, morphology correction, and adherence to rehab, most patients report significant improvements in pain and function. Athletes frequently return to sport after a staged, criteria-based program guided by objective strength and control measures.

If imaging shows advanced osteoarthritis with joint-space narrowing, hip arthroscopy is less predictable; in these scenarios we will discuss whether muscle-sparing hip replacement offers a more reliable outcome.

Prevention & Performance Tips

• Build gluteal strength and deep rotator control for hip–pelvic stability.
• Periodise training loads; avoid sudden spikes in volume, intensity, and deep flexion.
• Technique coaching for squats/lunges; avoid end-range impingement positions during flares.
• Use cross-training (bike/pool) to maintain fitness while symptoms settle.

When Should I See a Hip Specialist?

Seek expert review if you have groin pain with clicking, difficulty sitting, or persistent symptoms despite rest. Early assessment confirms the diagnosis, addresses modifiable factors, and helps prevent secondary cartilage injury.

Femoroacetabular Impingement — FAQs