What are the potential causes and management options for right groin pain radiating to the right thigh?

Right Groin Pain Radiating to Right Thigh

Start with plain radiographs (AP pelvis and frog-leg lateral hip views) as your initial imaging, then proceed to MRI hip without IV contrast if radiographs are negative or equivocal, as this presentation most likely represents intra-articular hip pathology such as osteoarthritis, labral tear, or femoroacetabular impingement. 1

Initial Diagnostic Approach

Imaging Strategy

• Plain radiographs are the mandatory first step for all patients with hip/groin pain, including AP pelvis and frog-leg lateral views to identify joint space narrowing, cam or pincer morphology, femoral head abnormalities, acetabular dysplasia, fractures, or bone tumors 1, 2
• Physical examination and radiography together have reasonable sensitivity and specificity for osteoarthritis, which commonly presents with groin pain radiating to the thigh 1
• If radiographs are negative, equivocal, or nondiagnostic, MRI hip without IV contrast is the next appropriate test with a rating of 9/9 ("usually appropriate") for detecting both intra-articular and extra-articular pathology 1, 2

Key Clinical Patterns to Identify

Intra-articular hip pathology (most common cause of groin pain radiating to thigh):

• Hip osteoarthritis: groin and lateral hip pain exacerbated by activity, alleviated by rest, progressive over time, reproduced by internal rotation on exam 1, 2
• Labral tears: often associated with femoroacetabular impingement (FAI), may show positive impingement test 1
• Osteonecrosis: insidious onset without trauma, higher risk in diabetic patients 2

Extra-articular soft tissue causes:

• Iliopsoas tendinitis/bursitis: anterior groin pain, may have internal snapping (coxa saltans) 1, 3
• Adductor longus tendinopathy: most common cause of adductor-related groin pain in athletes, intratendinous tear is most specific finding 4, 5
• Athletic pubalgia/core muscle injury: frequently mimics intra-articular hip pathology 3, 4

Neural causes:

• Ilioinguinal, iliohypogastric, genitofemoral, or lateral femoral cutaneous nerve entrapment can cause groin pain with radiation to thigh 6

Advanced Imaging and Diagnostic Procedures

When MRI is Indicated

MRI hip without IV contrast is superior for detecting:

• Labral tears, cartilage defects, bone marrow edema, occult fractures, osteonecrosis, and soft tissue abnormalities including tendinosis, bursitis, and muscle injuries 1, 2
• Surrounding soft tissue entities such as iliopsoas bursitis, subiliacus bursitis, trochanteric bursitis, abductor tendinosis or tears, and hamstring injuries 1

When to Consider MR Arthrography

• Direct MR arthrography (intra-articular gadolinium injection) is preferred over standard MRI when labral tear is strongly suspected clinically and provides superior visualization of labral pathology 1, 2
• MR arthrography has established superiority for evaluating labral tears with or without clinical findings consistent with FAI 1

Role of Diagnostic Injection

Image-guided intra-articular hip injection with anesthetic ± corticosteroid (rating 8/9 "usually appropriate") serves dual purposes: 1, 2

• Diagnostic confirmation: differentiates intra-articular from extra-articular pain sources
• Therapeutic benefit: provides symptomatic relief, particularly useful when concurrent low back, pelvic, or knee pathology exists and you need to exclude the hip as the pain source 1

Ultrasound-guided diagnostic injection into the iliopsoas bursa versus hip joint can differentiate iliopsoas tendinopathy from intra-articular pathology 3

Conservative Management Based on Diagnosis

For Hip Osteoarthritis (if confirmed)

• Oral NSAIDs should be used when not contraindicated (high quality evidence, strong recommendation) 1
• Oral acetaminophen may be considered when not contraindicated (consensus evidence) 1
• Physical therapy could be considered for mild-to-moderate symptomatic hip OA (high quality evidence, moderate recommendation) 1
• Avoid opioids for chronic hip pain (consensus recommendation against opioid use) 2

For Adductor-Related Groin Pain

• Active, supervised physical therapy is the initial treatment recommended 4
• MRI pelvis should be performed if diagnosis is unclear or symptoms have not improved after initial conservative management 4

For Inguinal-Related Groin Pain

• Dynamic ultrasonography should be performed to rule out true hernia and evaluate posterior abdominal wall weakness 4
• Initial management without evidence of hernia is physical therapy focusing on core strengthening and neuromuscular rehabilitation 4

Critical Pitfalls to Avoid

• Do not skip plain radiographs: They are essential for screening and guide selection of additional imaging techniques 1
• Beware of asymptomatic findings: Tendinosis, calcifications, and cortical erosions are common in athletes and may not be the pain source 5
• Consider referred pain: Spine, gynecologic, and gastrointestinal systems can all cause groin pain 3, 7
• Ultrasound has limited utility for hip joint evaluation: Cannot adequately visualize acetabular or femoral head cartilage, and is less sensitive than MRI for labral tears 1
• Nuclear medicine (bone scan, PET) is not useful for initial evaluation of chronic hip/groin pain unless infection or occult fracture is specifically suspected 1