Femoroacetabular Impingement (FAI): Causes, Symptoms, and How We Can Help

All information in this blog is supported by peer-reviewed research and current clinical guidelines. There is currently no dedicated NICE guideline for FAI specifically, so current evidence is used throughout. Reference numbers appear throughout, with the full list at the bottom of the page.

What Is Femoroacetabular Impingement?

Femoroacetabular impingement syndrome (FAIS) is a symptomatic, movement-related condition caused by premature contact between the acetabulum (the hip socket) and the femoral head or the junction between the femoral head and neck, causing repetitive microtrauma, labral disruption, and progressive degeneration of the hip joint. ¹ It is one of the most common causes of hip and groin pain in young and physically active individuals, with prevalence ranging from around 10 to 15% in young active patients and up to 94% of young patients presenting with hip pain. ²

Importantly, a diagnosis of FAI syndrome requires a specific triad of findings to be present together: symptoms, clinical signs on examination, and imaging findings. ¹ The presence of a bony variation on a scan alone, without symptoms or clinical signs, does not constitute FAI syndrome, this is a genuinely important distinction since imaging evidence of FAI morphology is common even in people without any symptoms at all.

The Three Types of FAI

FAI is classified into three types based on the location of the bony abnormality: ³

Cam morphology: an abnormally shaped femoral head or head-neck junction, where the femoral head is non-spherical, creating a bony bump that jams into the hip socket during movement, particularly with hip flexion. Cam impingement is three times more common in male athletes and is more typical in young, active men. ¹ ³

Pincer morphology: excessive coverage of the femoral head by the acetabulum, meaning the socket is too deep or oriented incorrectly, causing the rim of the socket to impinge on the femoral neck. Pincer impingement is more common in middle-aged athletic women. ¹

Mixed morphology: the most common presentation in clinical practice, where both cam and pincer features are present simultaneously. ³ Because both mechanisms are operating together, mixed morphology tends to produce the broadest range of symptoms and requires a comprehensive approach to treatment.

Common Signs and Symptoms

• Deep groin pain, often described as a catching, pinching, or aching sensation deep in the front of the hip

• Slow-onset, persistent groin pain is the most frequent initial presenting symptom ³

• Pain worse with sustained hip flexion, such as prolonged sitting, squatting, or driving

• Pain with pivoting, twisting, or rotating movements

• A clicking, catching, or locking sensation in the hip joint

• Reduced hip range of motion, particularly with internal rotation and flexion

• Pain that may radiate into the thigh or buttock in some cases

• Stiffness, particularly after periods of inactivity

Risk Factors

• Younger age, FAI most commonly presents in younger and physically active adults ³

• Male sex for cam morphology, with cam impingement being three times more common in men ¹

• Female sex for pincer morphology, with pincer impingement predominating in middle-aged athletic women ¹

• Caucasian background, identified as a risk factor in the research literature ³

• Family history of FAI morphology, reflecting a genuine genetic component ³

• Participation in high-intensity sport during adolescence, when the femoral head is still developing, particularly sport involving repeated hip flexion and rotation such as football, ice hockey, and dance ³

• Radiographic evidence of FAI, present in 36% of patients under 55 undergoing hip replacement for osteoarthritis, suggesting untreated FAI may contribute to early joint degeneration ¹

How FAI Can Progress If Left Unmanaged

This is worth understanding clearly, because FAI is not simply a condition to live with. If left untreated, FAI can lead to labral tears and chondral (cartilage) damage, and is recognised as a significant contributing factor in the development of early hip osteoarthritis. ² The repeated abnormal contact between the bony structures damages the labrum and the articular cartilage surrounding it over time, which is why early assessment and appropriate management genuinely matters for long-term joint health.

What to Look Out For

FAI is a benign, non-emergency condition. Please seek prompt medical assessment if you experience:

• Sudden, significant hip pain following trauma

• Inability to bear weight

• Fever, redness, or warmth around the hip

• Significant, unexplained weight loss alongside hip pain

• Rapidly progressive neurological symptoms

How Is It Diagnosed?

Diagnosis requires the combination of symptoms, clinical examination findings, and imaging. ¹ On physical examination, a positive FADIR test (flexion, adduction, internal rotation), also known as the anterior impingement sign, is the most consistently used clinical test, reproducing the patient's familiar deep groin pain. ³

Plain radiograph of the pelvis is the primary imaging modality, used to measure the alpha angle and lateral centre-edge angle to identify and quantify the severity of cam and pincer morphology. ³ MRI or MR arthrography is used where labral pathology needs to be assessed in more detail. ¹

Myths vs Facts

"I have FAI on my scan so I definitely need surgery." Not necessarily. Structural changes alone do not dictate symptoms, and emerging evidence has led to a genuine shift toward conservative management strategies as the first-line approach, with surgery considered when conservative treatment has been properly explored. ⁴

"FAI only affects older people." FAI is predominantly a condition of young and physically active adults, and is one of the most important causes of hip pain in this age group specifically. ¹

"There's nothing I can do without surgery." Conservative rehabilitation should be considered first-line treatment for FAI syndrome, as it provides significant improvements in pain relief, function, and quality of life while avoiding the risks associated with surgery. ⁵

How We Can Help

Conservative rehabilitation is the recommended first-line approach for mild to moderate FAI syndrome, and current evidence demonstrates genuine, meaningful improvements in pain, function, and quality of life through structured physiotherapy-based programmes. ⁵ ⁶

Osteopathic manual techniques and manual therapy: the physioFIRST trial, a well-designed pilot randomised controlled trial, specifically examined manual therapy to the hip alongside targeted strengthening as part of a structured FAI rehabilitation programme, finding moderate to large positive effects in hip pain, function, quality of life, trunk endurance, and strength across all hip muscle groups in the intervention group. ⁷ Manual therapy is used to address restriction and compensatory tension around the hip, pelvis, and lumbar spine, supporting overall movement quality alongside exercise.

Deep tissue and sports massage: targeted soft tissue work for the hip flexors, gluteal muscles, and surrounding lower limb structures, addressing the compensatory muscle tension that frequently develops alongside FAI.

Exercise and Rehabilitation: The Foundation of Conservative Management

Exercise-based physiotherapy, particularly programmes incorporating core stability, progressive strengthening, and neuromuscular training, has demonstrated consistently positive outcomes in FAI management. ⁵

Phase 1: Reducing irritability and restoring mobility

• Activity modification: temporarily avoiding sustained hip flexion positions, deep squatting, and pivoting movements that provoke impingement, without avoiding all movement

• Hip mobility work: gentle range of motion exercises within a pain-free range, focusing on the directions most restricted for your specific morphology

• Pain-guided movement: working within positions that do not reproduce the deep catching or groin pain characteristic of FAI

Phase 2: Building hip and lumbopelvic stability

• Hip external rotator strengthening: targeting the deep rotators of the hip joint, which are often underactive in FAI presentations

• Gluteal strengthening: progressive loading of the gluteus medius and maximus, central to hip stability and reducing impingement forces

• Core stability and lumbopelvic control: ensuring adequate lumbo-pelvic stability is one of the most important elements of conservative FAI management, as poor trunk control increases the mechanical load transferred through the hip joint during movement ⁸

• Hip adductor strengthening: often underactive and relevant to overall hip joint control

Phase 3: Functional and sport-specific rehabilitation

• Progressive return to squatting, lunging, and loading movements through full range

• Sport-specific movement retraining where relevant

• A graded return to training and competition guided by symptoms and functional capacity

Surgery Versus Conservative Management: What Does the Research Actually Show?

This is genuinely an evolving and interesting area of research, and it's worth being honest about what the evidence currently shows. A 2025 multilevel meta-analysis of randomised controlled trials comparing conservative treatment against hip arthroscopy found that surgery produced better outcomes on patient-reported outcome measures in the short to medium term. ⁹ However, the same body of research consistently supports conservative rehabilitation as a meaningful, effective first-line approach that should be properly explored before surgery is considered. ⁵ ⁶

The British Hip Society and UK Hip Physiotherapy Network are explicit that conservative rehabilitation should be considered the first-line treatment for FAI syndrome. ¹⁰ Surgery is generally considered when structured conservative management has been given a thorough trial and symptoms remain significantly limiting, particularly where labral or cartilage damage requires direct surgical intervention.

What to Expect at Your First Appointment

We will take a thorough history, including your activity levels, the specific movements that provoke your symptoms, and your goals for recovery. We will carry out a hands-on clinical assessment including the FADIR and FABER tests alongside a broader assessment of hip range of motion, muscle strength, and lumbopelvic control. We will explain clearly what we find and build a structured, progressive rehabilitation programme targeting the specific impairments identified, in line with current evidence.

Frequently Asked Questions

Do I need a scan to confirm FAI? Plain X-ray is the primary imaging tool for identifying FAI morphology. Clinical assessment can raise suspicion before imaging, but confirmation of the bony morphology and assessment of any associated labral pathology typically requires imaging.

Will I definitely need surgery? Not necessarily, and certainly not as a first step. Conservative rehabilitation is the recommended first-line approach for FAI syndrome, with meaningful evidence supporting its effectiveness for pain, function, and quality of life. ⁵

Can I keep playing sport? Activity modification during the acute phase is often helpful, but complete rest is rarely indicated. A graded, structured return to sport, guided by your symptoms and rehabilitation progress, is the goal.

How long will recovery take? This varies depending on the severity of the morphology, whether labral damage is present, and how long symptoms have been present. Many people see meaningful improvement over a course of 8 to 12 weeks of structured rehabilitation, though return to full sport may take longer.

Think this might be what's going on with your hip? Get in touch using the contact form and we will carry out a thorough assessment and build the right treatment plan for you.

BOOK YOUR APPOINTMENT HERE

References

1. Femoroacetabular Impingement Syndrome. PM&R KnowledgeNow. Updated April 2025. Available at: https://now.aapmr.org/femoral-acetabular-syndrome/

2. Treatment of cam-type femoroacetabular impingement using anterolateral mini-open and arthroscopic osteochondroplasty. PMC. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6637511/

3. Fortier LM, et al. An Updated Review of Femoroacetabular Impingement Syndrome. Orthopedic Reviews. 2022. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC9404268/

4. How to Build an Effective Conservative Treatment Plan for FAIS. Medbridge. 2025. Available at: https://www.medbridge.com/blog/managing-fais-without-surgery-the-role-of-rehabilitation-in-hip-pain

5. Optimizing Conservative Treatment for Femoroacetabular Impingement Syndrome: A Scoping Review of Rehabilitation Strategies. Applied Sciences. 2025;15(5):2821. Available at: https://www.mdpi.com/2076-3417/15/5/2821

6. Short-term Outcomes of Conservative Treatment for Femoroacetabular Impingement: A Systematic Review and Meta-Analysis. PMC. Available at: https://pmc.ncbi.nlm.nih.gov/articles/PMC6670054/

7. The Physiotherapy for Femoroacetabular Impingement Rehabilitation Study (physioFIRST): A Pilot Randomized Controlled Trial. Journal of Orthopaedic & Sports Physical Therapy. 2018. Available at: https://www.jospt.org/doi/10.2519/jospt.2018.7941

8. Conservative Management for Femoroacetabular Impingement (FAI). Fowler Kennedy Sport Medicine Clinic. Available at: https://www.fowlerkennedy.com/wp-content/uploads/2023/03/CONSERVATIVE-MANAGEMENT-FOR-FEMOROACETABULAR-IMPINGEMENT-FAI-November-2015.pdf

9. Ramadanov N, et al. Conservative treatment versus hip arthroscopy in patients with femoroacetabular impingement: a multilevel meta-analysis of randomized controlled trials. Bone and Joint Open. 2025. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12014245/

10. Physiotherapy as Conservative Treatment for FAI Syndrome. British Hip Society, UK Hip Physiotherapy Network. December 2024. Available at: https://britishhipsociety.com/Portals/0/Downloads/UK%20Hip%20Physiotherapy%20Network/PHYSIOTHERAPY-AS-CONSERVATIVE-TREATMENT-FOR-FAI-SYNDROME-13.12.2024.pdf