A 72-year-old man with a femoral neck fracture is being evaluated for surgical management. The orthopaedic team is debating between internal fixation with cannulated screws versus hemiarthroplasty. Which finding would most reliably predict a poor outcome with internal fixation alone and favour arthroplasty?

Explanation

## Intracapsular Femoral Neck Fracture: Internal Fixation vs Arthroplasty ### Garden Classification and Prognosis **Key Point:** The Garden classification grades femoral neck fractures by the degree of displacement and integrity of the medial cortex. Grades III–IV (displaced fractures with loss of medial cortical continuity) have significantly higher rates of avascular necrosis and non-union with internal fixation alone, making arthroplasty the preferred option. ### Garden Classification Overview | Grade | Description | Medial Cortex | Displacement | AVN Risk | Management | | --- | --- | --- | --- | --- | --- | | **I** | Incomplete/impacted | Intact | Minimal | <5% | Conservative or ORIF | | **II** | Complete, non-displaced | Intact | None | 10–15% | ORIF with cannulated screws | | **III** | Complete, partially displaced | Disrupted | Yes | 20–30% | ORIF or arthroplasty | | **IV** | Complete, fully displaced | Disrupted | Severe | 40–50% | Arthroplasty preferred | ### Why Displacement (Garden III–IV) Predicts Failure **High-Yield:** Displaced intracapsular fractures (Garden III–IV) have: 1. Severe disruption of the medial femoral circumflex artery (MFCA) blood supply 2. High rates of non-union (15–30%) and AVN (40–50%) even with optimal internal fixation 3. Poor functional outcomes in elderly patients if AVN develops In contrast, undisplaced fractures (Garden I–II) retain better blood supply and have much lower AVN risk, making internal fixation viable. ### Clinical Decision Algorithm ```mermaid flowchart TD A[Intracapsular femoral neck fracture]:::outcome --> B{Garden grade?}:::decision B -->|Grade I–II<br/>Non-displaced| C[Medial cortex intact<br/>MFCA preserved]:::outcome C --> D[Internal fixation<br/>with cannulated screws]:::action B -->|Grade III–IV<br/>Displaced| E[Medial cortex disrupted<br/>MFCA severely compromised]:::urgent E --> F{Patient age &<br/>functional status?}:::decision F -->|Young, active| G[ORIF attempt<br/>+ close follow-up]:::action F -->|Elderly, low demand| H[Hemiarthroplasty]:::action D --> I[Low AVN risk<br/>Good union rates]:::outcome H --> J[Immediate function<br/>Avoids AVN]:::outcome ``` **Clinical Pearl:** In elderly patients (>70 years) with displaced intracapsular fractures, hemiarthroplasty is now the standard of care because it provides immediate pain relief and function while avoiding the prolonged healing and high AVN risk of internal fixation. **Warning:** Do not confuse comminution of the greater trochanter (an extracapsular feature) with displacement of an intracapsular fracture. Greater trochanter involvement indicates an intertrochanteric fracture, which has a different prognosis and management. [cite:Rockwood & Green's Fractures in Adults 9e Ch 53]