## Management of Displaced Femoral Neck Fractures (Garden Grade IV) in Active Elderly Patients ### Pathophysiology of Displacement and AVN Risk Displaced femoral neck fractures (Grade III–IV) carry a significantly higher risk of avascular necrosis (AVN) because: 1. The medial and lateral femoral circumflex arteries are disrupted at the fracture site 2. Displacement compromises both the main blood supply and collateral circulation 3. AVN rates in Grade IV fractures reach 30–50% even with anatomic reduction This makes arthroplasty (rather than internal fixation) the preferred approach in elderly patients. ### THA vs. Hemiarthroplasty in Active Elderly Patients The critical decision in a **medically fit, active elderly patient (≥60 years)** with a displaced femoral neck fracture is whether to perform **Total Hip Arthroplasty (THA)** or **Hemiarthroplasty**. | Factor | Hemiarthroplasty | Total Hip Arthroplasty (THA) | |--------|-----------------|------------------------------| | **Indication** | Low-demand, frail elderly | Active, medically fit elderly | | **Acetabular component** | Native acetabulum retained | Replaced with cup | | **Acetabular erosion** | Progressive over time | Eliminated | | **Functional outcome** | Moderate | Superior | | **Re-operation rate** | Higher (acetabular wear) | Lower | | **Pain relief** | Good | Excellent | | **Dislocation risk** | Lower | Slightly higher (technique-dependent) | **Key Point:** According to current evidence (NICE guidelines, BOAST guidelines, and multiple RCTs including the HEALTH trial), **THA is preferred over hemiarthroplasty** in patients who are: - Medically fit for surgery - Cognitively intact - Independently mobile prior to injury - Expected to have reasonable life expectancy ### Why THA is the Most Appropriate Choice Here 1. **Grade IV fracture:** Complete displacement → arthroplasty is mandatory (ORIF has unacceptably high failure rates) 2. **Age 68 years:** Active elderly patient with good life expectancy — THA provides superior long-term functional outcomes 3. **Medically fit:** No contraindications to the more extensive THA procedure 4. **Active lifestyle implied:** A 68-year-old man who was ambulatory (fell down stairs) is a high-demand patient who will benefit from THA's superior functional outcomes 5. **Lower re-operation rates:** THA avoids the acetabular erosion and groin pain that necessitate conversion surgery after hemiarthroplasty ### Why Other Options Are Incorrect - **Option A (Cannulated screws/ORIF):** Appropriate only in young patients (<60 years) where joint preservation is paramount; in elderly patients with Grade IV fractures, failure rates (AVN, nonunion) exceed 30–50% - **Option C (Hemiarthroplasty):** Preferred in **low-demand, frail, or cognitively impaired** elderly patients; in a medically fit, active 68-year-old, THA provides better outcomes with lower re-operation rates - **Option D (Conservative/traction):** Not appropriate for a medically fit patient with a displaced fracture; associated with high mortality, pressure sores, and permanent disability **Clinical Pearl:** The HEALTH trial (NEJM, 2019) and subsequent meta-analyses confirm that THA results in significantly better functional outcomes (Harris Hip Score, Oxford Hip Score) compared to hemiarthroplasty in active elderly patients with displaced femoral neck fractures, with acceptable complication profiles. **High-Yield Mnemonic:** **FIT ELDERLY + DISPLACED = THA** - **F**it for surgery + **I**ndependently mobile + **T**hreshold age ≥60 → **THA** - Frail/demented/low-demand elderly → Hemiarthroplasty [cite: Campbell's Operative Orthopaedics, 13e Ch 56; Rockwood and Green's Fractures in Adults, 9e Ch 51; HEALTH Trial, NEJM 2019; NICE Clinical Guideline CG124 – Hip Fracture Management]
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