In a patient with right groin pain that began after lifting a heavy box, with soft‑tissue ultrasound negative for femoral or inguinal hernia and no enlarged lymph nodes, what differential diagnoses should be considered?

Differential Diagnosis for Right Groin Pain After Lifting

In a patient with acute groin pain following heavy lifting and negative ultrasound for hernia, you should systematically evaluate for musculoskeletal causes including adductor-related injury, iliopsoas-related injury, pubic-related pathology, and hip-related pain, while also excluding serious pathology such as stress fractures, infections, and referred pain from the lumbar spine.

Primary Musculoskeletal Differential Diagnoses

Based on the 2020 International Hip-related Pain Research Network consensus guidelines, groin pain in active adults falls into distinct categories that guide your workup 1:

Adductor-Related Groin Pain

• Most common musculoskeletal cause in patients with lifting-related injury
• Adductor muscle strain or tendinopathy at the pubic insertion
• Pain typically worsens with resisted hip adduction
• May have missed on standard soft tissue ultrasound if not specifically evaluated

Iliopsoas-Related Groin Pain

• Iliopsoas muscle strain or tendinopathy
• Pain localized to anterior groin, worsens with hip flexion against resistance
• Can occur from sudden forceful hip flexion during lifting

Pubic-Related Groin Pain

• Pubic symphysis pathology (osteitis pubis, symphyseal instability)
• Rectus abdominis insertion injury at pubic symphysis
• Pain at pubic bone, may radiate to groin

Hip-Related Pain

The consensus guidelines identify three main hip conditions to consider 1:

1. Femoroacetabular Impingement (FAI) Syndrome

   • Motion-related disorder with groin pain as primary symptom
   • May be unmasked by acute injury
   • Requires clinical signs plus imaging findings (cam/pincer morphology)

2. Acetabular Dysplasia/Hip Instability

   • Overload of acetabular rim during activities
   • Less likely with acute onset but consider in appropriate demographics

3. Intra-articular Pathology Without Distinct Osseous Morphology

   • Labral tears
   • Chondral lesions
   • Ligamentum teres tears

Critical "Red Flag" Pathologies to Exclude

The guidelines explicitly state these must be ruled out 1:

• Stress fractures (femoral neck, pubic rami)
• Infections (septic arthritis, osteomyelitis)
• Tumors
• Slipped capital femoral epiphysis (in appropriate age group)
• Avascular necrosis

Competing Musculoskeletal Sources

• Lumbar spine pathology with referred pain (must be screened)
• Sacroiliac joint dysfunction

Additional Considerations Beyond Guideline Scope

Occult Inguinal/Femoral Hernia

• Ultrasound has limitations; dynamic examination quality-dependent
• Consider MRI pelvis if high clinical suspicion persists 2
• Femoral hernias in women carry higher emergency surgery risk (4% mortality) and should not be missed 3

Athletic Pubalgia ("Sports Hernia")

• Weakness in posterior inguinal wall without frank hernia
• Chronic overload of abdominal aponeurosis
• May not be visible on standard ultrasound 4, 5

Nerve Entrapment

• Ilioinguinal nerve
• Genitofemoral nerve
• Lateral femoral cutaneous nerve (meralgia paresthetica)

Vascular Pathology

• Femoral artery pseudoaneurysm (rare without instrumentation)
• Deep vein thrombosis

Diagnostic Approach

A comprehensive clinical examination is essential as imaging has limited diagnostic utility for many of these conditions 1:

Physical Examination Maneuvers

Look for specific provocative tests 6:

• Resisted hip adduction (adductor pathology)
• Resisted hip flexion (iliopsoas pathology)
• Palpation of pubic symphysis (pubic-related pain)
• Flexion-adduction-internal rotation test (hip-related pain; negative test helps rule out hip pathology)
• Dynamic Valsalva examination for occult hernia

Imaging Strategy

If initial ultrasound is negative and clinical suspicion remains high:

1. MRI pelvis and hip without contrast is the gold standard next step 2

   • Near 100% sensitivity for occult fractures
   • Excellent for soft tissue injuries (adductors, iliopsoas, labrum)
   • Detects bone marrow edema, stress reactions
   • Can identify athletic pubalgia findings

2. CT pelvis is second-line if MRI contraindicated 2

   • Less sensitive than MRI but useful for bony detail
   • No role for contrast-enhanced CT in this setting

3. Plain radiographs (AP pelvis, frog-leg lateral hip) if not already done

   • Evaluate for FAI morphology, dysplasia, fractures
   • Low sensitivity but may show obvious pathology

Common Pitfalls to Avoid

• Don't assume negative ultrasound excludes all pathology - ultrasound is operator-dependent and may miss musculotendinous injuries, occult hernias, and intra-articular hip pathology 7, 8

• Don't focus solely on hernia - the differential is broad and musculoskeletal causes are common in lifting injuries 9, 7

• Don't forget to examine the hip joint - hip pathology commonly presents as groin pain and may coexist with other causes 1

• Multiple pathologies often coexist - one diagnosis doesn't exclude others 1

• Age and activity level matter - younger active patients more likely to have FAI syndrome or athletic pubalgia; older patients consider stress fractures and AVN

The key is recognizing that groin pain after lifting with negative hernia imaging requires systematic evaluation of all musculoskeletal structures, with MRI being the most comprehensive next imaging study if clinical examination doesn't clarify the diagnosis 2, 7.