What is the appropriate initial evaluation and management for a patient experiencing right thigh aches?

Initial Evaluation and Management of Right Thigh Aches

Begin with plain radiographs of the pelvis and hip as the first diagnostic test for right thigh pain, as this provides essential screening for common disorders and guides subsequent imaging decisions. 1

Initial Diagnostic Approach

History and Physical Examination - Key Features to Identify

• Pain characteristics: Determine if pain is groin-based (suggests intra-articular hip pathology), lateral (suggests trochanteric bursitis/abductor tendinopathy), or anterior thigh (suggests referred pain from hip or spine) 1
• Mechanical symptoms: Pain exacerbated by activity and relieved by rest suggests osteoarthritis; pain with internal rotation of the hip reproduces intra-articular pathology 1
• Red flags requiring urgent evaluation: Fever with severe pain (infection, diabetic muscle infarction), acute trauma history (Morel-Lavallée lesion), elderly thin female with nausea/vomiting (obturator hernia with bowel obstruction) 2, 3, 4
• Gait assessment: Antalgic gait pattern indicates significant hip pathology requiring imaging 1

First-Line Imaging: Plain Radiographs

Obtain radiographs of the pelvis and proximal femur (not just the ipsilateral hip) as the initial imaging study. 1

• Radiographs detect common disorders including osteoarthritis, dysplasia, femoroacetabular impingement, and primary bone tumors 1
• For osteoarthritis specifically, physical examination combined with radiography has reasonable sensitivity and specificity, potentially better than MRI 1
• Radiographs serve as an excellent screening tool and guide selection of additional imaging techniques 1

Algorithm for Further Evaluation Based on Radiograph Results

If Radiographs Show Osteoarthritis

Initiate conservative management with oral NSAIDs (strong recommendation, high-quality evidence) when not contraindicated. 1

• Consider oral acetaminophen as an alternative (consensus recommendation) 1
• Physical therapy should be considered for mild-to-moderate symptomatic hip osteoarthritis (moderate recommendation, high-quality evidence) 1
• If symptoms remain refractory to conservative measures, surgical consultation for total hip arthroplasty is appropriate 1

If Radiographs Are Negative, Equivocal, or Nondiagnostic

Proceed to MRI hip without IV contrast or ultrasound based on suspected pathology. 1

For Suspected Extra-Articular Soft Tissue Abnormalities (Tendonitis, Bursitis):

• MRI without IV contrast or ultrasound are both appropriate next steps 1
• Ultrasound is particularly useful for evaluating superficial structures like abductor tendons for tendinosis or calcific bursitis, and deeper structures like iliopsoas and adductor tendons 1
• Ultrasound can also guide therapeutic injections 1

For Suspected Labral Tear:

• MRI without IV contrast, MR arthrography, or CT arthrography are all appropriate 1
• Direct arthrography creates high contrast between articular surfaces, allowing detection of defects in articular cartilage, labrum, and capsule 1

For Suspected Femoroacetabular Impingement:

• MR arthrography or CT arthrography are appropriate 1

If Infection Is Suspected

Obtain MRI hip with or without IV contrast, or perform image-guided hip aspiration. 1

• Joint aspiration with fluid examination or culture can exclude joint infections and should be guided by imaging 1

Critical Pitfalls to Avoid

• Do not assume normal radiographs exclude significant pathology: Many soft tissue abnormalities, labral tears, and early cartilage damage are not visible on plain films 1, 5
• Consider rare but serious diagnoses in specific populations: Diabetic muscle infarction in poorly controlled diabetics (presents with severe pain, firm swelling, elevated ESR, normal creatine kinase), obturator hernia in thin elderly women (can present with isolated thigh pain), and Morel-Lavallée lesions after trauma 2, 3, 4
• Recognize referred pain patterns: Low back, pelvic, or knee pathology can cause thigh pain; if these are suspected, MRI hip without IV contrast or image-guided anesthetic injection can help exclude the hip as the pain source 1
• Avoid premature aspiration or injection: These procedures should not be performed until a diagnosis is suspected based on history, examination, and initial imaging 1

Role of Diagnostic/Therapeutic Injections

Image-guided injections of anesthetic with or without corticosteroids serve both diagnostic and therapeutic purposes. 1

• Intra-articular injection relieving pain confirms the pain originates from the joint 1
• Trochanteric injection can diagnose and treat trochanteric bursitis 1
• When arthrography is performed, simultaneous intra-articular injection of anesthetic and steroid provides diagnostic information while being therapeutic 1