Diagnosing FAI Syndrome: Key Clinical Clues

Anterior hip or groin pain in young adults can have several potential causes, and distinguishing between them isn’t always straightforward, particularly during a short consultation or if you rarely see this patient group.

Depending on your experience, Femoroacetabular Impingement (FAI) syndrome might be at the forefront of your mind or barely on your radar. Either way, it’s worth considering, as delayed recognition can delay access to appropriate care, with potential physical and psychological consequences.

In his Case Study, Dr Michael O’Brien walks through his assessment, diagnosis and management of a 20-year-old with hip pain. This blog highlights a few clinical pearls to help you recognise FAI syndrome in practice.

If you want to see exactly how Dr Michael O’Brien assessed and managed this patient, watch his full Case Study here.

Is it an intra-articular or extra-articular source of pain?

After considering other causes, including lumbar referral, femoral stress fracture, inflammatory arthritis and tumours, the next question is whether symptoms suggest an intra-articular or extra-articular source.

Extra-articular conditions are often (but not always) aggravated by resisted movements. The Doha agreement categorises groin pain into adductor-related, iliopsoas-related, inguinal-related and pubic-related presentations, alongside hip-related causes.

However, extra-articular symptoms can occur secondary to intra-articular pathology, so pain during resisted testing doesn’t necessarily rule out a hip joint contribution.

Intra-articular conditions may be more readily provoked by hip range-of-motion testing, particularly flexion and rotation.

The case

Michael’s patient presented with bilateral hip and groin pain. Clicking began in 2023, followed by pain in August 2024. He described deep anterior and lateral hip pain, occasionally radiating into the proximal anterior thigh.

Sitting, walking his dogs, mopping and leg press aggravated his symptoms. He also reported occasional painful clicking and feelings of instability, without locking, giving way or paraesthesia.

On examination, left hip flexion was painful at 95°, and internal rotation was limited and painful bilaterally. Together, these findings raised suspicion of an intra-articular contribution.

Recognising FAI syndrome

Identifying a possible intra-articular source doesn’t automatically mean FAI syndrome.

Other considerations include hip dysplasia, microinstability, and labral or cartilage pathology. Diagnosing FAI syndrome requires three components: symptoms, clinical signs and imaging findings.

Michael explains this diagnostic approach in the following clip from his Case Study:

Symptoms

Patients may report movement-related hip or groin pain, clicking or feelings of instability. For Michael’s patient, deep anterior/lateral hip pain was aggravated by sitting and loaded hip flexion during leg press.

Clinical signs

Painful hip flexion and internal rotation, including symptom reproduction during FADIR or internal rotation at 90-degrees hip flexion can support suspicion of FAI syndrome.

Michael’s patient demonstrated:

• Hip flexion: 95° bilaterally, reproducing pain on the left.
• Internal rotation at 90° hip flexion: 40° left and 35° right, painful bilaterally.
• External rotation at 90° hip flexion: 70° left and 60° right, pain-free.
• Single-leg tasks: Reduced stability during single-leg stance and squatting, with pain at the bottom of the squat.
• Pubic symphysis stress and hyperextension–external rotation tests were negative.

Imaging

X-ray or MRI findings help complete the diagnostic picture by identifying potential structural contributors. However, imaging must be interpreted alongside symptoms and clinical signs. Michael explores imaging and its role in clinical decision-making in greater detail in the full Case Study.

Could femoral retroversion be contributing?

Beyond cam morphology, femoral and acetabular version may influence hip mechanics and symptoms.

In this case, Craig’s test demonstrated approximately 5° of internal rotation on the left and 0° on the right, which raised suspicion of femoral retroversion. Watch Michael demonstrate the assessment in this clip from his Case Study:

Craig’s test may raise suspicion of altered femoral version but cannot confirm it. Further imaging may be needed to assess the anatomy, particularly when structural factors could influence movement restrictions and clinical decisions.

Diagnosis is only the first step

Recognising FAI syndrome is just the beginning of clinical decision-making.

In the full Case Study, Michael explains how he weighed conservative and surgical options, considering symptom duration, imaging findings, patient expectations, beliefs and financial costs through shared decision-making.

He also covers education, activity modification, targeted strengthening, movement retraining, adjunct treatments and when to consider further investigation or specialist referral.

Wrapping up

FAI syndrome isn’t always straightforward to diagnose, particularly when symptoms overlap with other causes of hip and groin pain.

Understanding the clinical clues, interpreting them together and knowing when further investigation is warranted can help you make more informed decisions.

And once you’ve reached a diagnosis, the next step is helping your patient get back to what matters to them.

Want to see how Michael approached this patient’s care? Watch Michael’s full Case Study here.