CIM Case: Periprosthetic Femoral Fracture Post THR

Clinical Scenario

Patient: 78-year-old woman Presentation: Fall at home 2 hours ago, unable to weight-bear, severe right thigh pain Relevant history: Cemented THR 8 years ago for primary osteoarthritis, known osteoporosis on treatment, no pre-injury hip symptoms, lives alone, uses walking stick Examination findings:

• Right leg shortened and externally rotated
• Marked tenderness over mid-thigh
• Unable to straight leg raise
• Swelling and bruising developing over lateral thigh
• Knee examination limited by pain
• Neurovascularly intact distally (palpable pulses, normal sensation, able to move toes)

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Investigations Provided

Laboratory Results

Imaging

Image 1: AP and Lateral Radiographs of Right Hip and Femur

Radiological features:

• Cemented total hip replacement in situ
• Spiral oblique fracture extending from just below lesser trochanter to mid-shaft
• Fracture involves stem tip level
• Cement mantle appears intact
• No obvious radiolucent lines around proximal stem
• Varus angulation at fracture site
• Generalised osteopaenia

Image 2: AP Pelvis for Comparison

Findings:

• Previous X-rays available from 2 years ago
• No significant interval change in stem position
• No previous progressive radiolucent lines
• Comparison confirms no pre-existing loosening

Questions & Model Answers

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Key Teaching Points

Pattern Recognition

This pattern suggests Periprosthetic Femoral Fracture:

• Elderly patient with THR and low-energy fall
• Unable to weight-bear with thigh pain (not hip pain)
• Shortened, externally rotated leg
• Fracture around or below prosthetic stem

Vancouver Classification Summary:

Critical Decision Point: Is the stem LOOSE?

• Get previous X-rays for comparison
• Look for radiolucent lines, subsidence, cement fractures
• Final assessment is INTRAOPERATIVE

Critical Management Points

1. Treat as fragility fracture - orthogeriatric pathway, optimise medically
2. Blood loss can be significant - check Hb, resuscitate
3. Previous X-rays essential - assess for pre-existing loosening
4. B1 = fix fracture only - cables proximally, locking plate distally
5. B2/B3 = revise stem - long distally-engaging modular stem
6. Early mobilisation - reduces mortality in elderly

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Common Examiner Follow-ups

Q: "What is the mortality rate for periprosthetic fractures?"

1-year mortality is 10-20%, similar to hip fracture mortality. These are fragility fractures in elderly patients and should be managed with the same urgency and optimisation as native hip fractures.

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Q: "How do you differentiate B1 from B2 radiographically?"

Key point: If there is ANY doubt about stability, intraoperative assessment is definitive.

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Q: "What are your options for a B3 fracture with severe bone loss?"

• Long uncemented modular stem bypassing fracture
• Strut allografts (cortical strut onlay) for structural support
• Impaction bone grafting for contained defects
• Proximal femoral replacement for severe proximal bone loss (tumour prosthesis)
• Careful surgical technique - avoid further bone loss during cement removal

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Q: "Can you operate on anticoagulation?"

This is a surgical emergency requiring prompt treatment. Options:

• Warfarin: Reverse with vitamin K ± prothrombin complex concentrate
• DOACs: Consider reversal agents (idarucizumab for dabigatran, andexanet alfa for Xa inhibitors) or wait 24-48h if possible
• Aspirin: Can usually proceed with appropriate haemostasis
• Balance: Weigh thrombotic risk against bleeding risk with haematology input

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Related Topics

• Vancouver Classification
• Revision Hip Arthroplasty
• Osteoporosis in Orthopaedic Surgery
• Geriatric Hip Fractures
• Cemented vs Uncemented Stems