What is the diagnosis and recommended treatment for a adult patient with no significant past medical history, presenting with lateral knee pain that radiates up and down, worsens with activity such as walking and standing, and improves with rest, who has been experiencing symptoms for a month after stepping over a stone while walking, with alleviating factors including rest and Tylenol (acetaminophen) but not Diclofenac, and denies direct trauma, fall, tingling/numbness, lower back pain, knee swelling, knee buckling/catching, and nighttime pain?

Lateral Knee Pain: Diagnosis and Treatment

Most Likely Diagnosis

This presentation is most consistent with iliotibial band (ITB) syndrome, given the lateral knee pain that worsens with activity (walking, standing), improves with rest, radiates proximally and distally, and occurred after a precipitating event (stepping over a stone) in the absence of trauma, swelling, mechanical symptoms, or nighttime pain 1, 2, 3.

Diagnostic Reasoning

Key Clinical Features Supporting ITB Syndrome:

• Lateral knee pain that is activity-related and worsens throughout the day with continued use 1, 3
• Pain radiation up and down the lateral thigh, consistent with ITB distribution 1
• Aggravated by repetitive knee flexion/extension during walking and standing 2, 3
• Relief with rest, which is characteristic of overuse tendinopathy 1, 3
• Absence of mechanical symptoms (no buckling, catching, or swelling) argues against meniscal pathology or intra-articular derangement 4
• No nighttime pain, which helps exclude inflammatory arthropathy or malignancy 4

Physical Examination Priorities:

• Palpate for point tenderness over the lateral femoral epicondyle approximately 2-3 cm proximal to the lateral joint line 2, 3
• Assess for weakness of hip abductors (gluteus medius), which is a causative factor in ITB syndrome 1, 3
• Evaluate for myofascial tightness of the ITB using Ober's test 3
• Rule out joint effusion by palpation and ballottement, as its absence supports extra-articular pathology 4

Treatment Algorithm

Phase 1: Initial Conservative Management (Weeks 1-3)

Immediate activity modification is the cornerstone of initial treatment 1, 3:

• Reduce or temporarily cease aggravating activities (prolonged walking, standing) 1, 3
• Implement the "small amounts often" principle for necessary activities 5

Pharmacologic management should prioritize NSAIDs over acetaminophen for this presentation 6:

• Switch from acetaminophen to oral NSAIDs (ibuprofen 400-600mg TID or naproxen 500mg BID), as NSAIDs demonstrate superior efficacy for moderate-to-severe musculoskeletal pain and the patient has already failed acetaminophen 4, 6
• Since oral diclofenac was ineffective, consider topical NSAIDs (diclofenac gel applied QID to lateral knee) as an alternative or adjunct, which provides clinical efficacy with minimal systemic absorption 4
• Screen for NSAID contraindications: GI bleeding history, chronic kidney disease stage 3+, heart failure, uncontrolled hypertension 6

Physical therapy prescription should be specific 1, 3:

• Stretching exercises for the ITB once acute inflammation subsides (typically after 3-5 days) 1, 3
• Strengthening of hip abductors (gluteus medius) with emphasis on eccentric contractions, as weakness is a primary causative factor 1, 3
• Myofascial release techniques to address soft tissue restrictions before progressing to strengthening 1

Phase 2: Persistent Symptoms (Weeks 3-6)

If pain persists beyond 3 days with ambulation or visible swelling develops, consider corticosteroid injection 3:

• Ultrasound-guided injection into the space between the ITB and lateral femoral epicondyle is effective for symptom relief 7
• This approach is supported for acute exacerbations with local inflammation 3, 7

Continue structured rehabilitation with progression to:

• Integrated movement patterns and triplanar motions 1
• Gradual return to activity, starting with faster-paced running (which paradoxically causes less ITB irritation) rather than slow jogging 1

Phase 3: Refractory Cases (Beyond 6-8 Weeks)

Imaging is indicated if symptoms persist despite optimal conservative management 4, 7:

• MRI without contrast is the preferred modality to evaluate for alternative diagnoses including subchondral insufficiency fracture, lateral meniscal pathology, or other soft tissue abnormalities 4
• Ultrasound can identify ITB thickening, bursitis, or fluid collection between the ITB and lateral femoral epicondyle 7

Surgical referral should be considered only after 6 weeks of failed conservative treatment 1, 3:

• Arthroscopic release of ITB attachment to lateral femoral epicondyle is the preferred surgical technique 8
• Open ITB lengthening is reserved for truly refractory cases 1

Critical Pitfalls to Avoid

• Do not continue acetaminophen monotherapy when NSAIDs are not contraindicated, as acetaminophen has inferior efficacy for musculoskeletal pain 4, 6
• Avoid premature imaging in the first 3-6 weeks unless red flags emerge (nighttime pain, constitutional symptoms, progressive neurologic deficits) 4
• Do not prescribe opioids for this condition, as current evidence shows limited benefit with high risk of adverse events in musculoskeletal pain 6
• Ensure hip abductor strengthening is included in physical therapy, as failure to address gluteus medius weakness leads to treatment failure 1, 3
• Avoid returning to full activity too quickly, as gradual progression prevents recurrence 1

Alternative Diagnoses to Consider

While ITB syndrome is most likely, if the patient fails to respond to appropriate treatment, consider:

• Lateral meniscal pathology (though absence of mechanical symptoms makes this less likely) 4
• Patellofemoral pain syndrome with lateral tracking (though pain location is more lateral than anterior) 4
• Subchondral insufficiency fracture (more common in elderly females, but MRI would be needed for diagnosis) 4
• Gluteus medius tendinopathy (though pain is typically more proximal over greater trochanter) 5