Femoroacetabular Impingement Diagnosis and Treatment

Anatomical Location and Pathophysiology

• The British Journal of Sports Medicine recommends that femoroacetabular impingement (FAI) syndrome is an intra-articular hip joint disorder causing groin pain from abnormal bone contact, involving abnormal contact between the femoral head and acetabular rim during hip motion 1, 2
• FAI syndrome results from cam morphology (femoral head-neck junction abnormality), pincer morphology (acetabular overcoverage with LCEA >40°), or mixed patterns, according to the British Journal of Sports Medicine 3
• The condition causes repetitive mechanical loading leading to labral tears, chondral damage, and early osteoarthritis, as reported by the British Journal of Sports Medicine 1, 2

Pain Location and Characteristics

• The primary location of pain in FAI syndrome is the groin, which is the hallmark symptom, according to the British Journal of Sports Medicine 1, 2, 4
• Pain may radiate to the back, buttock, or thigh, and is motion-related, worsened by hip flexion, adduction, and internal rotation, as reported by the British Journal of Sports Medicine 1, 2

Physical Examination Findings

• A positive FADIR test (flexion-adduction-internal rotation) is indicative of FAI syndrome, though a negative test helps rule out hip-related pain, according to the British Journal of Sports Medicine 1, 2, 5
• Limited hip internal rotation and flexion are common findings in FAI syndrome, as reported by Praxis Medical Insights 6

Diagnostic Imaging Approach

• The initial imaging for FAI syndrome includes AP pelvis and lateral femoral head-neck radiographs (Dunn, frog-leg, or cross-table views), as recommended by the British Journal of Sports Medicine and the Journal of the American College of Radiology 5, 7
• Advanced imaging such as MRI or MR arthrography is used to assess labral tears, chondral damage, and ligamentum teres pathology, according to the Journal of the American College of Radiology and Praxis Medical Insights 7, 3

Patient Demographics

• FAI syndrome typically affects young to middle-aged active adults (20-50 years), including athletes and active individuals with repetitive hip flexion activities, as reported by the British Journal of Sports Medicine 1, 2, 4

Treatment Approaches

• The American College of Sports Medicine recommends a conservative trial of 3-6 months of activity modification, physical therapy, and NSAIDs for FAI syndrome, as reported by Praxis Medical Insights 3
• Surgical indications for FAI syndrome include failed conservative management with persistent symptoms, or MRI-confirmed labral/chondral damage, according to Praxis Medical Insights 3

Critical Diagnostic Pitfalls

• The British Journal of Sports Medicine and Praxis Medical Insights recommend that lumbar spine pathology must be excluded in all hip pain evaluations, as radicular pain can mimic both FAI and GTPS conditions 1, 2, 6, 8
• Incidental findings are extremely common in asymptomatic individuals for both FAI morphology and gluteal tendon changes, and clinical correlation is mandatory, as reported by Praxis Medical Insights 3, 8

Cam‑Type Femoroacetabular Impingement: Evidence‑Based Diagnostic and Management Guidelines

Initial Diagnostic Approach

• Standard radiographic series (anteroposterior pelvis plus a lateral femoral head‑neck view such as Dunn, frog‑leg, or cross‑table) should be obtained first to identify cam morphology, and must be interpreted together with a clinical picture of groin pain and a positive FADIR test. [9][10]
• A positive FADIR maneuver (flexion‑adduction‑internal rotation) supports the diagnosis of cam‑type FAI, although its specificity is limited. [9][11]
• Before confirming FAI, clinicians must exclude serious alternative pathologies (e.g., tumors, infection, stress fracture, slipped capital femoral epiphysis). 9
• Concurrent musculoskeletal conditions of the pelvis should be screened for, as they may mimic or coexist with FAI. 10

Imaging Protocol

• Initial plain‑film imaging (AP pelvis and lateral femoral head‑neck radiographs) is required to detect loss of femoral head‑neck offset indicative of cam morphology. 10
• Diagnosis must not rely on imaging alone; cam morphology is frequently present in asymptomatic individuals, so imaging findings must be correlated with symptoms and physical‑exam signs. [12][11]
• When conservative therapy fails and surgical planning is contemplated, advanced imaging (MRI or MR arthrography) should be performed to evaluate associated labral tears, chondral injury, and ligamentum teres pathology. 10

First‑Line Conservative Management

• A physiotherapist‑led rehabilitation program that emphasizes hip‑muscle strengthening and movement quality leads to improvements in pain, functional ability, and quality‑of‑life outcomes for patients with cam‑type FAI. [13][14]

Surgical Indications

• Arthroscopic hip surgery is indicated only after a minimum 3–6‑month trial of conservative care has failed and the patient continues to have persistent groin pain together with positive clinical findings (positive FADIR test and limited range of motion). 11

Critical Pitfalls to Avoid

• Intervention should never be based solely on imaging findings; cam morphology without corresponding symptoms and positive clinical signs does not merit treatment. [12][11]

Diagnostic Criteria and Imaging for Cam‑Type Femoroacetabular Impingement

Diagnostic Triad

• Cam‑type FAI is confirmed only when groin pain, a positive FADIR test, and radiographic evidence of cam morphology are all present; imaging findings without symptoms do not justify treatment. [15][16]

Exclusion of Red‑Flag Pathology

• Before evaluating for FAI, clinicians must exclude serious conditions such as tumors, infections, stress fractures, and slipped capital femoral epiphysis (SCFE) through targeted history (night pain, systemic symptoms, inability to bear weight, fever) and appropriate imaging. [15][17]
• In younger patients, Perthes disease should be considered as a differential diagnosis. 16

Typical Clinical Presentation

• The usual patient is a young, athletic male (~20 years old) who presents with groin pain that may radiate to the back, buttock, or thigh. [16][17]

Physical Examination Findings

• The FADIR test (flexion‑adduction‑internal rotation) is a useful screening tool: a positive result supports intra‑articular hip pathology, while a negative result helps exclude hip‑related pain, though the test has limited specificity. [15][18]
• Lumbar spine screening is mandatory in all patients to rule out referred pain from L1‑L3 radiculopathy. 18

Initial Radiographic Assessment

• Standard AP pelvis and lateral femoral‑head‑neck views (Dunn, frog‑leg, or cross‑table lateral) are required first‑line to detect cam morphology, identified by loss of the normal femoral head‑neck offset. 18
• Cam morphology is defined radiographically by an alpha angle > 50.5° at the anterosuperior head‑neck junction. 18
• Radiographic findings must always be interpreted in conjunction with symptoms and clinical signs; they should not be used in isolation. 18

Advanced Imaging Indications

• MRI or MR arthrography is indicated when:

Prevalence of Incidental Cam Morphology

• Cam morphology is present in about 14 % of asymptomatic individuals (≈ 24.7 % of asymptomatic men), highlighting the importance of correlating imaging with clinical findings before initiating treatment. 18

Treatment Decision Principle

• Imaging findings alone should not dictate intervention; treatment is warranted only when cam morphology is accompanied by compatible symptoms and positive clinical examination. 18