What is the best course of action for a patient with anterior right hip pain, limited internal rotation, and otherwise full range of motion (ROM), considering potential conditions such as osteoarthritis or femoroacetabular impingement?

Anterior Right Hip Pain with Limited Internal Rotation

Obtain plain radiographs (AP pelvis and lateral hip) immediately as your first diagnostic test, then proceed to MRI if radiographs are negative or equivocal, as this presentation strongly suggests either femoroacetabular impingement (FAI) or early hip osteoarthritis. 1

Clinical Significance of Your Findings

• Limited internal rotation with anterior hip pain is the hallmark physical examination finding for FAI, with 88% of FAI patients demonstrating pain on anterior impingement testing and internal rotation averaging only 9 degrees in flexion 2
• The preservation of full ROM in other planes makes extra-articular pathology (trochanteric bursitis, iliopsoas tendinitis) less likely, as these conditions typically present with different pain patterns and physical examination findings 1
• Internal rotation limitation correlates directly with underlying bony anatomy (r = 0.97), not soft tissue contractures, indicating structural pathology requiring imaging confirmation 3

Diagnostic Algorithm

Step 1: Plain Radiographs First

• Order AP pelvis and lateral femoral head-neck views bilaterally to evaluate for hip osteoarthritis, FAI morphology (cam or pincer lesions), acetabular dysplasia, and occult fractures 1
• For suspected FAI, add specialized views including false profile or Dunn view to better characterize the head-neck offset and alpha angle 1
• Radiographs serve as an excellent screening tool and guide selection of additional imaging, with reasonable sensitivity and specificity for osteoarthritis when combined with physical examination 1

Step 2: MRI Without Contrast if Radiographs Are Negative/Equivocal

• MRI should be the first advanced imaging technique after radiographs for detecting labral tears, early cartilage damage, bone marrow edema, and soft tissue pathology not visible on plain films 1
• MRI is highly sensitive and specific for labral pathology, which commonly accompanies FAI and presents with your exact clinical picture 1
• Do not skip radiographs and proceed directly to MRI, as this violates consensus guidelines and may miss important bony pathology visible on plain films 1

Step 3: Diagnostic Injection if Diagnosis Remains Unclear

• Image-guided intra-articular hip injection with local anesthetic (with or without corticosteroid) definitively confirms the hip joint as the pain generator 1
• Pain relief following intra-articular injection confirms intra-articular pathology and predicts response to surgical intervention if needed 1

Initial Conservative Management

For Confirmed FAI or Early Osteoarthritis

• Refer to physical therapy immediately as the American Academy of Orthopaedic Surgeons provides high-quality evidence with moderate strength recommendation supporting either formal PT or supervised exercise programs before surgical options 1
• NSAIDs and acetaminophen provide symptomatic relief during the rehabilitation phase 1
• Intra-articular corticosteroid injection can be considered for symptomatic relief (high-quality evidence, moderate strength recommendation), providing both diagnostic confirmation and therapeutic benefit 1
• Avoid hyaluronic acid injections, as high-quality evidence with strong recommendation states these should NOT be used for symptomatic hip osteoarthritis 1
• Avoid opioids entirely for chronic hip pain, as consensus recommendations oppose their use for symptomatic hip osteoarthritis 1

Physical Therapy Goals

• Focus on hip strengthening, core stabilization, and activity modification to reduce impingement mechanics 2
• Arthroscopic cam decompression (if FAI is confirmed) can improve internal rotation from approximately 10 degrees preoperatively to 30 degrees at 3 months postoperatively, with corresponding improvement in alpha angle 4

Critical Pitfalls to Avoid

• Do not diagnose based on imaging alone—incidental findings are extremely common in asymptomatic individuals, and clinical correlation is essential 1
• Do not assume this is primary hip joint pathology without imaging confirmation, as referred pain from the lumbar spine or sacroiliac joint can mimic hip pathology 1
• Do not delay diagnosis—the average time from symptom onset to definitive FAI diagnosis is 3.1 years, with patients seeing an average of 4.2 healthcare providers and 13% undergoing unsuccessful surgery at incorrect anatomic sites 2
• Screen for "red flag" conditions including femoral neck stress fracture (requires urgent evaluation), inflammatory arthritis in younger adults, and slipped capital femoral epiphysis in adolescents 5

Surgical Considerations if Conservative Management Fails

• For FAI without significant osteoarthritis (Tönnis grade 0-1), arthroscopic hip surgery with cam/pincer decompression and labral repair shows good outcomes in appropriately selected patients 6, 4
• Surgical outcomes deteriorate significantly with Tönnis grade 2 or higher osteoarthritis, with success rates below 50% at 5 years in patients with risk factors (age >45, obesity, CE angle <25°, female sex) 6
• For advanced osteoarthritis unresponsive to conservative treatment, total hip arthroplasty provides >90% survival at 15 years even in patients under 50 years old 6