# CIM Case: Paediatric Proximal Femur Fracture ## Clinical Scenario **Patient:** 13-year-old boy **Presentation:** Fall from bicycle at high speed 3 hours ago, unable to weight-bear, right hip pain **Relevant history:** High-energy mechanism, no head injury, no other injuries identified, previously healthy, no bone disease, no medications **Examination findings:** - Right leg shortened and externally rotated - Unable to actively move hip - Severe pain with any passive motion - Swelling around hip region - No open wound - Knee and ankle examination limited by hip pain - Neurovascularly intact distally (palpable dorsalis pedis, normal sensation, able to wiggle toes) - Abdomen soft, pelvis stable --- ## Investigations Provided ### Laboratory Results | Test | Result | Normal Range | Interpretation | |------|--------|--------------|----------------| | Hb | 115 g/L | 120-150 g/L | ↓ Mild decrease (blood loss) | | WCC | 12.5 ×10⁹/L | 5-15 ×10⁹/L | Upper normal (stress response) | | Platelets | 310 ×10⁹/L | 150-400 ×10⁹/L | Normal | | Group & Screen | O positive | - | Available for transfusion | | Coagulation | Normal | - | Normal | ### Imaging **Image 1: AP Pelvis and Lateral Hip Radiograph** **Radiological features:** - Displaced transcervical fracture of right femoral neck - Basicervical extension with comminution of inferior neck - No obvious intertrochanteric extension - Shortening and varus angulation - Physis open (skeletal immaturity) - No dislocation of femoral head - Left hip normal - No other pelvic fractures **Classification:** Delbet Type II (Transcervical) - displaced ## Questions & Model Answers **Diagnosis:** Displaced paediatric femoral neck fracture (Delbet Type II - Transcervical) **Significance:** - **SURGICAL EMERGENCY** - requires urgent reduction and fixation - High AVN rate (up to 30-50% for displaced transcervical fractures) - Time to reduction correlates with AVN risk - Rare injury (~1% of all paediatric fractures) - High-energy mechanism required in children **Delbet Classification:** | Type | Location | AVN Risk | Treatment | |------|----------|----------|-----------| | **I** | Transphyseal (with/without dislocation) | 90-100% if dislocated | Urgent closed/open reduction, screw fixation | | **II** | Transcervical | 30-50% | Urgent reduction, screw/plate fixation | | **III** | Basicervical (cervico-trochanteric) | 20-30% | Reduction, screw/plate fixation | | **IV** | Intertrochanteric | <10% | ORIF, hip screw or plate | **This Patient:** Type II (Transcervical) with displacement - HIGH RISK for AVN **Why AVN Occurs:** - Femoral head blood supply is tenuous in children - Retinacular vessels (lateral epiphyseal) are main supply by age 4 - Displaced fracture disrupts these vessels - Intracapsular haematoma creates tamponade effect - Delay in reduction allows further ischemic damage > **Consultant Tip:** This is a time-critical injury. Goal is reduction within 24 hours, ideally within 6-12 hours. AVN risk increases with delay. **Initial Resuscitation:** - ATLS approach if high-energy mechanism - IV access, fluid resuscitation - Analgesia (IV morphine titrated to effect) - Nil by mouth for urgent surgery - Blood group and screen **Urgent Surgical Planning:** **Timing:** Theatre within 6-12 hours ideally, maximum 24 hours **Investigations Required:** - AP pelvis and lateral hip X-rays (done) - CT scan NOT routinely needed (delays surgery) - MRI NOT indicated acutely **Preoperative Checklist:** | Item | Status | |------|--------| | Consent (parents) | Required - discuss AVN risk prominently | | Fasting | Confirm NBM status | | Antibiotics | Prophylactic cephalosporin | | Thromboprophylaxis | Not routinely needed in children | | Blood available | Cross-match if significant blood loss expected | | Equipment | Fracture table, paediatric hip screw, cannulated screws, image intensifier | **Communication:** - Inform parents of URGENCY - Discuss AVN risk (30-50% for Type II) - Explain need for capsulotomy - Long-term follow-up required (2+ years) **Do NOT:** - Apply traction and delay surgery - Obtain unnecessary imaging - Delay for non-essential reasons > **Consultant Tip:** This injury gets priority over elective cases. Treat like a femoral neck fracture in an adult - time is critical. **Surgical Approach and Technique:** **Positioning:** - Fracture table with traction - Alternatively: radiolucent table with manual traction **Reduction:** **Closed Reduction (first attempt):** - Longitudinal traction - Internal rotation to correct external rotation deformity - Slight abduction - Confirm reduction on AP and lateral fluoroscopy **Open Reduction (if closed fails):** - Anterior (Smith-Petersen) or anterolateral approach - Watson-Jones approach also acceptable - Visualise fracture, remove haematoma - Reduce under direct vision **Capsulotomy:** **ESSENTIAL STEP - must decompress haematoma:** - Intracapsular pressure from haematoma impedes blood flow - Aspirate or incise capsule - Leave capsule open or loosely close **Fixation Options:** | Age | Fixation | Notes | |-----|----------|-------| | <2 years | Spica cast ± K-wires | Rare to need fixation | | 2-8 years | Cannulated screws (2-3) | Avoid crossing physis if possible | | 8-16 years | Cannulated screws OR paediatric hip screw | May need to cross physis | **Screw Placement:** - Cannulated 4.5-6.5mm screws - 2-3 screws in inverted triangle configuration - Avoid physis if possible (may cause premature closure) - If must cross physis, use smooth wires or partially threaded screws - Confirm position on AP and lateral **This Patient (13 years old):** - Closed reduction attempted first - If successful, 2-3 cannulated screws - Capsulotomy mandatory - If closed reduction fails, open through Watson-Jones approach > **Consultant Tip:** Capsulotomy is not optional. Failure to decompress is a technical error that increases AVN risk. **Complications by Timing:** **Early Complications:** | Complication | Incidence | Management | |--------------|-----------|------------| | AVN | 30-50% (Type II) | See monitoring protocol below | | Nonunion | 5-10% | Valgus osteotomy ± bone graft | | Malunion (coxa vara) | 20-30% | Valgus osteotomy if neck-shaft angle <110° | | Infection | 1-2% | Antibiotics, debridement if deep | | Hardware prominence | Common | Remove once healed | **Late Complications:** | Complication | Incidence | Management | |--------------|-----------|------------| | Premature physeal closure | 30-60% | Monitor for LLD, may need contralateral epiphysiodesis | | LLD | Variable | Shoe raise, epiphysiodesis, or limb lengthening | | Coxa magna | Variable | Usually asymptomatic | | Chondrolysis | Rare | Supportive, may resolve | | Late OA | Variable | Long-term follow-up | **AVN Monitoring Protocol:** | Time | Investigation | Looking For | |------|---------------|-------------| | 6 weeks | X-ray | Early sclerosis, crescent sign | | 3 months | X-ray ± MRI | Subchondral changes, fragmentation | | 6 months | X-ray | Head collapse, fragmentation | | 12 months | X-ray | Remodelling vs collapse | | 2 years | X-ray | Final head shape | | Long-term | As needed | OA development | **MRI for AVN:** - More sensitive than X-ray for early AVN - Consider at 6-12 weeks if X-ray normal but clinical suspicion - Low signal on T1, variable T2 signal in AVN **Bone Scan:** - Traditional method for assessing head vascularity - Cold scan suggests AVN (no blood flow) - Hot scan is reassuring but not definitive > **Consultant Tip:** AVN may take 6-12 months to become radiographically evident. Follow these children for minimum 2 years. **Definition:** Coxa vara = neck-shaft angle <120° (normal 130-135° in children) **Clinical Significance:** - Limp (Trendelenburg gait) - Abductor weakness - Limb shortening - Altered hip biomechanics - May progress if physis involved **Assessment:** | Measurement | Normal | This Patient | |-------------|--------|--------------| | Neck-shaft angle | 130-135° | Measure on AP X-ray | | Hilgenreiner epiphyseal angle | <25° | >60° indicates progression risk | | LLD | 0 | Measure clinically and radiographically | **Management Algorithm:** **Observation Indications:** - Neck-shaft angle >110° - Hilgenreiner angle <45° - No symptoms - Young child with remodelling potential **Surgical Indications:** - Neck-shaft angle <110° - Progressive deformity - Symptomatic (limp, pain) - Hilgenreiner angle >60° **Surgical Options:** **Subtrochanteric Valgus Osteotomy:** - Lateral closing wedge or medial opening wedge - Target neck-shaft angle 140-150° (overcorrect slightly) - Fix with blade plate or paediatric hip screw - Correct rotation if needed **Technical Considerations:** - Remove previous hardware if in the way - Achieve stable fixation - May need to address LLD separately later **Expected Outcomes:** - Good improvement in gait and function - May need hardware removal later - Monitor for recurrence if growth plate still open > **Consultant Tip:** Coxa vara is common after paediatric femoral neck fractures. Operate if neck-shaft angle <110° or progressive. **Initial Counselling (Preoperatively):** **Key Points to Discuss:** | Topic | What to Say | |-------|-------------| | **Urgency** | "This fracture needs surgery tonight/urgently to give the best chance of the bone healing well." | | **AVN risk** | "Even with the best surgery, there is a 30-50% risk of the blood supply to the ball of the hip being damaged. This can lead to problems with the bone." | | **Long-term follow-up** | "We will need to follow your son for at least 2 years, possibly longer, to check for complications." | | **Possible future surgery** | "He may need more surgery in the future if complications develop." | **What is AVN (Parent-Friendly Explanation):** - "The ball of the hip joint gets its blood supply through small vessels" - "When the bone breaks, these vessels can be damaged" - "Without enough blood, parts of the bone can die and crumble" - "We decompress the joint and fix the fracture quickly to give the best chance of saving the blood supply" **Postoperative Counselling:** **Immediate Postop:** - Touch weight-bearing with crutches for 6-12 weeks - Hip precautions (no high impact activities) - Wound care, signs of infection **Follow-up Schedule:** | Time | Visit Purpose | |------|---------------| | 2 weeks | Wound check, X-ray | | 6 weeks | X-ray, start increasing weight-bearing | | 3 months | X-ray, assess healing | | 6 months | X-ray, assess for AVN | | 12 months | X-ray, assess for late complications | | 2 years | Final X-ray assessment | | Long-term | Annual until skeletal maturity | **If AVN Develops:** | Scenario | Management | |----------|------------| | Early AVN (pre-collapse) | Protected weight-bearing, observation | | AVN with collapse | May need containment surgery (similar to Perthes) | | Severe AVN | Salvage procedures in adulthood (hip replacement) | **Prognosis by Type:** | Delbet Type | Good Outcome | Complications Likely | |-------------|--------------|----------------------| | IV | 90% | Rare | | III | 75% | Occasional | | II | 50-60% | Common | | I | <20% | Very likely | > **Consultant Tip:** Be honest with parents. Document the AVN risk discussion clearly. This fracture has a guarded prognosis despite optimal treatment. --- ## Key Teaching Points ### Pattern Recognition **This pattern suggests Paediatric Femoral Neck Fracture:** - High-energy trauma in a child - Shortened, externally rotated leg - Unable to weight-bear - Severe pain with any hip motion - X-ray: displaced femoral neck fracture with open physis **Distinguish from SUFE:** | Feature | Femoral Neck Fracture | SUFE | |---------|----------------------|------| | Mechanism | High-energy trauma | Low/no trauma | | Onset | Acute | Often insidious | | Habitus | Any | Often obese | | X-ray | Visible fracture line | Physeal widening, metaphyseal blanch | | Treatment | Urgent ORIF | Urgent in situ pinning | ### Critical Management Points 1. **SURGICAL EMERGENCY** - reduce and fix within 24 hours (ideally 12 hours) 2. **Capsulotomy is mandatory** - decompress haematoma to improve perfusion 3. **AVN risk is high** - 30-50% for Type II despite optimal treatment 4. **Delbet classification determines prognosis** - Type I worst, Type IV best 5. **Long-term follow-up essential** - minimum 2 years for AVN monitoring 6. **Document AVN risk discussion** - medico-legal importance --- ## Common Examiner Follow-ups **Q: "Why is capsulotomy important?"** The femoral head in children has a tenuous blood supply: - **Intracapsular haematoma** increases pressure within the joint capsule - **Tamponade effect** compresses the remaining retinacular vessels - **Further ischemia** occurs in addition to vessel damage from fracture - **Capsulotomy** or aspiration relieves this pressure Studies show lower AVN rates with capsulotomy, though evidence is limited by small numbers. It is considered standard of care in paediatric femoral neck fractures. --- **Q: "How do you fix across an open physis?"** Options for fixation crossing the physis: - **Smooth K-wires** - least damage, but less stable - **Partially threaded screws** - threads stay in epiphysis, smooth portion crosses physis - **Small diameter screws** - minimise physeal damage - **Limit number of screws** - 2 screws may be better than 3 if crossing physis Accept some physeal damage for stable fixation - the priority is fracture healing and AVN prevention. Premature physeal closure is a lesser problem than AVN or nonunion. --- **Q: "This child develops AVN at 6 months. What are your options?"** Management depends on severity and age: **Mild AVN (Ficat I-II, no collapse):** - Protected weight-bearing - Serial X-rays - May remodel, especially in younger children **Moderate AVN (early collapse):** - Consider containment (similar to Perthes principles) - Femoral varus osteotomy to improve coverage - Pelvic osteotomy if stiff hip **Severe AVN (significant collapse):** - May need salvage procedures when older - Hip arthrodesis (rare, for young active patient) - Total hip replacement (after skeletal maturity) **Key Point:** Young children have some remodelling potential. Severe AVN in an adolescent has poor prognosis. --- **Q: "What is the Ratliff classification?"** Ratliff classification is an outcome classification based on final result: | Type | Outcome | |------|---------| | **I** | Good - normal or near-normal hip | | **II** | Fair - some abnormality but functional | | **III** | Poor - significant disability, AVN, or need for salvage surgery | It is used to report outcomes in studies but doesn't guide treatment. --- ## Related Topics - Slipped Upper Femoral Epiphysis - Perthes Disease - Paediatric Hip Fracture Fixation - Avascular Necrosis - Subtrochanteric Osteotomy - Paediatric Trauma Principles