How should a young active adult (15‑35 years) with insidious groin pain and suspected cam‑type femoroacetabular impingement be evaluated and managed?

Cam-Type Femoroacetabular Impingement: Evaluation and Management

Diagnostic Confirmation Requires a Triad

Cam-type FAI is diagnosed when groin pain, positive clinical signs (particularly a positive FADIR test), and radiographic evidence of cam morphology are all present together—imaging findings alone without symptoms do not warrant treatment. 1, 2

Critical First Step: Exclude Red Flags

Before pursuing FAI workup, you must rule out serious pathology that can mimic hip pain:

• Tumors, infections, stress fractures, and slipped capital femoral epiphysis (SCFE) must be excluded through history (night pain, constitutional symptoms, inability to bear weight, fever) and appropriate imaging 1, 2
• Lumbar spine pathology (L1-L3 radiculopathy) can refer sharp lancinating pain to the groin and must be screened in every patient with a neurologic exam 2, 3, 4
• Perthes disease should be considered in younger patients within this age range 1, 3

Clinical Presentation Pattern

The typical patient is a young athletic male around 20 years old presenting with:

• Groin pain as the hallmark symptom, though pain may radiate to the back, buttock, or thigh 1, 2
• Motion-related pain worsened by hip flexion, adduction, and internal rotation (activities like getting in/out of cars, prolonged sitting, squatting) 2
• Limited hip internal rotation and flexion on examination 2

Physical Examination Protocol

• Perform the FADIR test (flexion-adduction-internal rotation): A positive test supports intra-articular pathology, while a negative test helps rule out hip-related pain, though specificity is limited 1, 2
• Mandatory lumbar spine screening in all cases to exclude referred pain 1, 2, 4
• Assess hip range of motion, particularly internal rotation at 90° flexion 5

Important caveat: Clinical tests have good sensitivity but poor specificity—they are useful for screening but cannot definitively confirm the diagnosis alone 1

Imaging Algorithm

Step 1: Initial Radiographs (Required First-Line)

Obtain AP pelvis and lateral femoral head-neck views (Dunn, frog-leg, or cross-table lateral) to identify cam morphology—the loss of normal femoral head-neck offset 1, 2, 4

• Cam morphology is characterized by an alpha angle >50.5° at the anterosuperior femoral head-neck junction 6, 5
• Imaging must always be interpreted in conjunction with symptoms and clinical signs, never in isolation 1, 2

Step 2: Advanced Imaging (When Indicated)

MRI or MR arthrography should be obtained when:

• Conservative management has failed and surgical planning is being considered 1, 2, 4
• You need to evaluate associated intra-articular damage (labral tears, chondral lesions, ligamentum teres pathology) 1, 2, 7

Key MRI findings in cam-type FAI:

• Anterosuperior acetabular cartilage lesions that are well-defined and may be 1-1.5 cm from the rim, initially sparing the labrum 8, 7, 6
• Osseous bump formation at the femoral neck 6
• Labral detachment from underlying bone in advanced cases 8

Critical Imaging Pitfall

Cam morphology is present in 14% of asymptomatic individuals (24.7% of asymptomatic men), so incidental findings are extremely common and clinical correlation is mandatory. 5 Never treat imaging findings without corresponding symptoms and positive clinical examination.

Management Algorithm

First-Line: Conservative Management (3-6 Months Minimum)

All patients should undergo a trial of physiotherapist-led rehabilitation emphasizing hip muscle strengthening and movement quality before considering surgery. 2

• Activity modification and NSAIDs as adjuncts 2
• This approach improves pain, functional ability, and quality of life 2

Surgical Indications

Arthroscopic hip surgery (femoral osteoplasty to restore head-neck offset) is indicated only when:

1. A minimum 3-6 month trial of conservative care has failed 2
2. Persistent groin pain continues with positive FADIR test and limited range of motion 2
3. MRI confirms associated labral/chondral damage 2, 7

Major contraindication: Advanced chondral wear or pre-existing osteoarthritis is the strongest predictor of poor surgical outcomes 7

Surgical Technique Considerations

• Arthroscopic femoral osteoplasty removes excess bone to restore normal femoral head-neck offset 8, 9
• Comprehensive fluoroscopic assessment (6 AP views in different rotations) and dynamic assessment of impingement-free range of motion are critical to avoid residual deformity, which is a leading cause of surgical failure 9
• Anterosuperior cartilage lesions are the classic pathology requiring concurrent treatment 8, 6

Common Pitfalls to Avoid

• Never base treatment decisions on imaging alone—cam morphology without symptoms does not merit intervention 1, 2, 5
• Do not miss coexisting pathology—labral tears frequently coexist with FAI and acetabular dysplasia 4
• Always screen the lumbar spine—referred pain from L1-L3 radiculopathy mimics FAI 2, 3, 4
• Remember that hip pathology can present as knee pain in adolescents and young adults, particularly with SCFE 3, 4
• Recognize that both cam and pincer morphology often coexist (mixed FAI), though isolated cam is more common than isolated pincer 8