What are the potential causes of posterior right hip pain in a patient in their 50s, with pain exacerbated by external rotation and to a lesser extent by internal rotation and flexion, and normal sensory and motor examination findings?

Posterior Right Hip Pain in a 50-Year-Old: Differential Diagnosis and Workup

Yes, obtain plain radiographs (AP pelvis and lateral hip views) immediately as the first diagnostic step, as this presentation most likely represents either hip osteoarthritis, femoroacetabular impingement (FAI), or ischiofemoral impingement. 1, 2, 3

Most Likely Diagnoses Based on Examination Findings

Primary Considerations

Posterior extra-articular ischiofemoral impingement is the leading diagnosis given the predominant pain on external rotation with posterior hip location. 4, 5

• This occurs when the space between the ischium and lesser trochanter narrows, causing impingement during hip extension, external rotation, and adduction 5
• Patients typically present with lower buttock and posterior hip pain exacerbated by these specific movements 5
• The pattern of pain primarily with external rotation (rather than internal rotation) strongly suggests this extra-articular posterior pathology 4, 5

Hip osteoarthritis remains a strong consideration in this age group despite the atypical posterior pain location. 6, 1

• Classic presentation includes groin pain with internal rotation reproducing symptoms, but pain can radiate to the buttock 6, 1
• Your patient has pain with internal rotation and flexion (though lesser), which fits the typical pattern 6, 1
• Age over 50 significantly increases likelihood 6

Femoroacetabular impingement (FAI) should be considered, particularly posterior FAI. 2, 7

• Posterior FAI can cause pain with external rotation and extension 4, 7
• Patients with increased femoral anteversion exhibit posterior hip pain and limited external rotation 4
• Pain triggered by hip flexion combined with internal rotation is characteristic, though your patient has more pain with external rotation 7

Secondary Considerations

Referred pain from lumbar spine or sacroiliac joint must be excluded. 1, 2, 3

• Normal sensory and motor examination makes radiculopathy less likely but does not exclude facet-mediated or SI joint pain 3
• Posterior hip pain frequently originates from spinal pathology 3

Deep gluteal syndrome with sciatic nerve entrapment is possible with posterior hip pain. 3

• Typically presents with posterior hip and buttock pain 3
• Normal sensory/motor exam makes this less likely but does not exclude it 3

Hamstring tendinopathy at the ischial origin can mimic posterior hip pain. 3

• Pain typically worsens with hip flexion and resisted knee flexion 3

Diagnostic Algorithm

Step 1: Obtain Plain Radiographs Immediately

Order AP pelvis and lateral femoral head-neck views bilaterally. 1, 2, 3

• Radiographs rapidly identify hip osteoarthritis (joint space narrowing, subchondral sclerosis, osteophytes, cystic changes) 1
• Evaluate for FAI morphology including cam lesions (flattened or convex head-neck junction) and pincer lesions (acetabular retroversion or over-coverage) 2, 7
• Assess ischiofemoral space narrowing (distance between ischium and lesser trochanter) 5
• Rule out occult fractures, acetabular dysplasia, and other bony pathology 2

Step 2: Advanced Imaging if Radiographs Are Negative or Equivocal

Obtain MRI of the hip without contrast if plain films are non-diagnostic but clinical suspicion remains high. 1, 2

• MRI detects labral tears, early cartilage damage, bone marrow edema, and soft tissue pathology not visible on radiographs 2
• MRI visualizes ischiofemoral space soft tissue impingement and sciatic nerve compression 5
• Consider MRI of lumbar spine if referred pain is suspected based on clinical findings 2, 8

Step 3: Diagnostic Injection if Diagnosis Remains Unclear

Image-guided intra-articular hip injection with local anesthetic definitively confirms the hip joint as the pain generator. 2, 8

• If pain resolves with injection, intra-articular pathology (OA, FAI, labral tear) is confirmed 2
• If pain persists, extra-articular causes (ischiofemoral impingement, referred pain) are more likely 2

Initial Conservative Management

For Suspected Hip Osteoarthritis or FAI

Initiate NSAIDs immediately (strong recommendation, high-quality evidence). 6, 1

• Oral NSAIDs should be used when not contraindicated for symptomatic hip OA 6
• Acetaminophen may be considered if NSAIDs are contraindicated (consensus recommendation) 6

Refer to physical therapy (moderate recommendation, high-quality evidence). 6, 1, 2

• PT should be considered for mild-to-moderate symptomatic hip OA 6
• Target hip muscle strengthening, particularly hip abductors, adductors, flexors, and rotators 1

Consider intra-articular corticosteroid injection for symptomatic relief (moderate recommendation, high-quality evidence). 6, 1, 2

• Provides both diagnostic confirmation and therapeutic benefit 2

For Suspected Ischiofemoral Impingement

Conservative management includes NSAIDs, activity modification, and physical therapy focused on hip strengthening. 5

• Avoid activities that exacerbate symptoms (hip extension, external rotation, adduction) 5
• If conservative treatment fails after 6-8 weeks, surgical decompression may be required 5

Critical Pitfalls to Avoid

Do not assume this is primary hip joint pathology without imaging confirmation. 2, 8, 3

• The predominance of external rotation pain (rather than internal rotation pain) suggests extra-articular pathology 4, 5
• Referred pain from lumbar spine or SI joint can mimic hip pathology 1, 2, 3

Do not proceed to advanced imaging without obtaining plain radiographs first. 2, 8, 3

• This violates consensus guidelines and may miss important bony pathology 2, 8

Do not diagnose based on imaging alone. 2, 8

• Incidental findings are extremely common in asymptomatic individuals—clinical correlation is essential 2, 8
• Poor correlation exists between radiographic severity and pain intensity in hip OA 1

Avoid opioids entirely for chronic hip pain (consensus recommendation). 2, 8

• Opioids should not be used for treatment of symptomatic hip OA 6

Do not use hyaluronic acid injections (strong recommendation, high-quality evidence). 2

• Intra-articular hyaluronic acid injection should NOT be considered for symptomatic hip OA 6