import { HighYieldBox, ExamCheatSheet, Tabs, Tab, ComparisonTable, VivaScenario, ContentSection, SpecialTestCard , MedicalImage} from '@/components/content' # Irritable Hip Examination (Child) The limping child with an irritable hip is a common exam scenario. Examiners expect you to differentiate transient synovitis from septic arthritis using clinical examination and Kocher criteria. Remember: septic arthritis is a surgical emergency - you must know how to identify it. ## Quick Reference One-Pager ## Understanding the Irritable Hip **Irritable Hip:** A clinical syndrome of acute hip pain and limited movement in a child, requiring systematic evaluation to exclude serious pathology. **Common Causes by Age:** | Age Group | Most Likely Causes | |-----------|-------------------| | 0-3 years | Septic arthritis, osteomyelitis, DDH | | 3-10 years | Transient synovitis (most common), septic arthritis, Perthes | | 10-16 years | SUFE, Perthes (young end), trauma | **Key Principle:** Transient synovitis is a diagnosis of exclusion - always rule out septic arthritis first. **Kocher Criteria for Septic Arthritis:** 1. Fever greater than 38.5°C 2. Non-weight-bearing on affected leg 3. ESR greater than 40 mm/hr 4. WCC greater than 12,000/mm³ **Probability of Septic Arthritis:** - 0 predictors: 0.2% - 1 predictor: 3% - 2 predictors: 40% - 3 predictors: 93% - 4 predictors: 99.6% Some centers add CRP greater than 20 as 5th criterion. ## History Taking **Presenting Complaint:** - Duration of symptoms (hours vs days) - Onset (sudden vs gradual) - Pain character and location - Weight-bearing status **Associated Features:** - Fever (measure temperature) - Recent viral illness (supports transient synovitis) - General wellbeing (eating, drinking, activity level) - Night pain (red flag for malignancy) **Past History:** - Previous hip problems - Recent trauma - Immunocompromise - Sickle cell disease **Red Flag History:** - High fever - Rapid deterioration - Systemically unwell - Not eating/drinking ## Observation **First Impressions:** - Sick vs well-appearing child - Comfortable vs distressed at rest - Position of comfort **Lying Position:** - Hip held in flexion, abduction, external rotation - This position maximizes hip joint capsule volume - Reduces intracapsular pressure **Standing/Walking (if possible):** - Willingness to weight-bear - Antalgic gait (short stance phase) - Trendelenburg gait ## Gait Assessment **Can Child Weight-Bear?** - Non-weight-bearing is Kocher criterion - Willingness improves prognosis - Compare with other leg **Antalgic Gait:** - Shortened stance phase on affected side - Quick off painful leg - May lean toward affected side **Trendelenburg Gait:** - Pelvis drops on swing side - Trunk lurches to stance side - Suggests abductor weakness/inhibition **Stiff Hip Gait:** - No hip movement during swing - Circumduction or hip hiking - Suggests fixed or very painful hip ## Examination on Bed **Test in This Order:** 1. **Log roll first** (gentlest, most sensitive) 2. **Flexion** (usually least painful) 3. **Abduction/Adduction** 4. **Internal rotation** (most restricted in septic arthritis) 5. **External rotation** **Compare with Normal Side:** - Always compare ROM bilaterally - Note any asymmetry - Quantify restriction **Key Finding in Septic Arthritis:** Marked restriction of ALL movements, especially internal rotation, with severe pain. ## Differentiating Features **Clinical Decision Making:** - If 0-1 Kocher criteria: Observe with serial examination - If 2 or more Kocher criteria: Aspirate hip (USS-guided) - If pus on aspiration or high clinical suspicion: Emergency surgical washout - Never delay treatment while waiting for investigations if child is toxic ## Complete Hip Examination **Spine:** - Discitis can present as hip pain - Examine for spinal tenderness - Assess spinal movement **Knee:** - Hip pathology can refer to knee - "Knee pain = examine hip" - Check knee examination is normal **Lymph Nodes:** - Inguinal lymphadenopathy - Suggests infection **Skin:** - Look for rashes (reactive arthritis, JIA) - Check for bruising (NAI, malignancy) - Insect bites (reactive synovitis) ## Age-Specific Considerations **Infant/Toddler Considerations:** - Cannot report symptoms - May just be irritable or off feeds - Pseudoparalysis (not moving leg) - Higher risk of septic arthritis - Consider NAI in unusual presentations - May present as refusal to crawl/walk **Examination Challenges:** - May not cooperate - Observe spontaneous movement - Watch for asymmetry - Examine during distraction **School-Age Considerations:** - Transient synovitis peak age - Perthes disease 4-8 years typically - Usually cooperative for examination - Can describe pain location **Key Differentials:** - Transient synovitis (most common) - Septic arthritis - Perthes disease - JIA **Adolescent Considerations:** - SUFE must be excluded - May have atypical Perthes presentation - Consider stress fractures (athletes) - Consider referred pain from spine **Red Flags:** - Bilateral symptoms (SUFE can be bilateral) - Obligatory external rotation with flexion (SUFE) - Night pain (malignancy) ## Investigations to Request **Blood Tests:** - FBC (WCC for Kocher criteria) - ESR (for Kocher criteria) - CRP (more sensitive for infection, some include as 5th criterion) - Blood cultures (before antibiotics) **Imaging:** - **X-ray pelvis AP and frog lateral**: Rule out Perthes, SUFE - **Ultrasound hip**: Detect effusion (sensitivity greater than 95%) **Second-Line:** - MRI: If diagnosis unclear - Hip aspiration: USS-guided if 2 or more Kocher criteria **Aspiration Findings:** - Turbid/purulent = likely septic - Clear yellow = likely transient synovitis - Send for microscopy, culture, cell count ## Summary Presentation ## Examination Sequence 1. **Observation**: General appearance, position in bed, distress level 2. **Temperature**: Check actual temperature (Kocher criterion) 3. **Weight-bearing**: Observe if child will stand and walk 4. **Gait**: Antalgic, Trendelenburg, stiff-hip pattern 5. **Log roll**: Most sensitive test - do first 6. **ROM**: Flexion, abduction, IR, ER - compare sides 7. **Thomas test**: Fixed flexion deformity 8. **Spine**: Tenderness, movement 9. **Knee**: Examine to exclude referred pain 10. **Systemic**: Lymph nodes, rash, general wellbeing ## Examiner Tips