What is the differential diagnosis for groin pain?

Differential Diagnosis for Groin Pain

Exclude Life-Threatening and Serious Pathology First

Before considering common musculoskeletal causes, immediately rule out stress fractures, tumors, infections, and slipped capital femoral epiphysis (SCFE) in appropriate age groups. 1

• Stress fractures (femoral neck or pubic ramus) present with insidious onset, night pain, inability to bear weight, and focal bone tenderness 2
• Tumors manifest with night pain, constitutional symptoms, and progressive worsening 2
• Septic arthritis or osteomyelitis show acute onset, fever, inability to bear weight, and severe rest pain 2
• SCFE must be considered in adolescents and young adults, often presenting as medial thigh or knee pain with external rotation deformity 2, 3

Primary Intra-Articular Hip Causes

Femoroacetabular Impingement (FAI) Syndrome

• Most common hip condition in young and middle-aged active adults presenting with hip-related groin pain 1
• Characterized by groin pain with hip flexion, adduction, and internal rotation movements 1, 2
• Positive FADIR (flexion-adduction-internal rotation) test, though a negative test helps rule out hip-related pain 1, 2
• Imaging shows cam, pincer, or mixed morphology on radiographs 1, 2

Acetabular Labral Tears

• Present with sharp, catching pain in the groin/medial hip with mechanical symptoms 2
• Often coexist with FAI syndrome or acetabular dysplasia 2
• Require MRI or MR arthrography for definitive diagnosis 2

Hip Osteoarthritis

• Medial groin and thigh aching discomfort exacerbated by activity and relieved by rest 2
• Pain with internal rotation and limited range of motion on examination 2, 4
• Plain radiographs typically diagnostic, showing joint space narrowing and osteophytes 1

Acetabular Dysplasia/Hip Instability

• Second most common hip condition in young and middle-aged active adults with hip-related pain 1
• Presents with medial groin pain and sensation of instability 2
• Misalignment between femoral head and acetabulum visible on imaging 2

Extra-Articular and Referred Pain Sources

Iliopsoas-Related Pain

• Anterior/medial groin pain with pain on resisted hip flexion 2
• Can be caused by tendinopathy or, rarely after total hip replacement, by hematoma from acetabular component impingement 5

Adductor-Related Pain

• Medial groin pain with tenderness over adductor tendons 1
• Pain with resisted adduction movements 1

Inguinal-Related Pain

• Pain in the inguinal region, may indicate inguinal hernia or sports hernia 1
• Requires differentiation from musculoskeletal causes 1

Lumbar Spine Pathology (Critical to Screen)

• Must be excluded in all patients with groin pain as it commonly refers pain to the groin and medial thigh 1, 2, 3
• Sharp lancinating pain radiating down the leg, induced by sitting, standing, or walking 2, 4
• Often present at rest and improved by position change 2, 4
• Results from irritation of L1-L3 nerve roots 6

Sacroiliac Joint Dysfunction

• Refers pain to groin/medial hip region 2
• Tenderness over SI joint with positive provocative SI joint tests 2

Osteitis Pubis

• Aseptic inflammation of the pubic symphysis in young physically active patients 6
• Can correlate with femoroacetabular impingement 6
• Degenerative changes in older patients; must distinguish from septic osteitis pubis 6

Diagnostic Algorithm

Step 1: History and Red Flag Assessment

• Determine if night pain, constitutional symptoms, inability to bear weight, or fever present 1, 2
• Assess if pain is activity-related or present at rest 2
• In adolescents, specifically inquire about medial thigh or knee pain (may indicate SCFE) 2, 3

Step 2: Physical Examination

• FADIR test: Positive suggests intra-articular pathology; negative helps rule out hip-related pain (though limited clinical utility) 1, 2
• Assess hip range of motion, particularly internal rotation (limited in osteoarthritis) 2
• Mandatory lumbar spine screening in all cases to exclude referred pain 1, 2, 3
• Palpate adductor tendons, iliopsoas, and pubic symphysis for focal tenderness 1
• Perform SI joint provocative tests 2

Step 3: Imaging Protocol

• First-line: AP pelvis and lateral femoral head-neck radiographs 2, 4
• Advanced imaging: MRI or MR arthrography for intra-articular structures when radiographs inconclusive or surgery considered 1, 2
• Ultrasound useful for superficial structures like adductor tendons 1
• CT without IV contrast rated most appropriate for chronic hip pain when advanced imaging needed 1

Critical Clinical Pitfalls

• Incidental imaging findings are extremely common in asymptomatic athletes—clinical correlation is mandatory 2, 3
• Hip pathology frequently presents as knee pain, and spine pathology can present as hip pain 2, 3
• Coexisting pathology is the rule, not the exception: labral tears often coexist with FAI or dysplasia 2
• Clinical examination and diagnostic imaging both have limited diagnostic utility alone; a comprehensive approach combining both is essential 1
• In patients after total hip replacement, consider iliopsoas hematoma from acetabular component malposition if chronic groin pain develops with active flexion deficit 5