Hemiarthroplasty for Femoral Neck Fracture

Absolute Indications (Garden III/IV Femoral Neck Fracture):

• Displaced intracapsular femoral neck fracture in elderly (typically >70 years)
• Low functional demand (walks with aids, limited community ambulation)
• Cognitive impairment (dementia - compliance with hip precautions unreliable)
• Limited life expectancy (<5-10 years)
• Significant medical comorbidities favouring shorter operative time
• No pre-existing acetabular arthritis on imaging

Relative Indications:

• Undisplaced fractures (Garden I/II) in very elderly with severe osteoporosis where fixation likely to fail
• Pathological fractures from metastatic disease (palliative hemiarthroplasty)
• Failed internal fixation of femoral neck fracture (salvage procedure)
• Elderly patient with rheumatoid arthritis (bone quality concerns)

• Active patient with independent community ambulation (walking without aids)
• Cognitively intact with good life expectancy (>10 years)
• Pre-existing acetabular arthritis or inflammatory arthropathy
• Younger patient (age 60-70) with displaced fracture
• Pre-existing hip symptoms suggesting osteoarthritis
• Inflammatory arthritis (RA, seronegative arthropathy)

Absolute Contraindications:

• Active sepsis or local infection
• Medical instability precluding surgery
• Palliative patient with very limited life expectancy (comfort measures only)

Relative Contraindications:

• Severe osteoporosis with concern for periprosthetic fracture (still usually proceed)
• Anticoagulation that cannot be reversed (delay if possible)
• Significant cardiac disease increasing BCIS risk (consider uncemented)

Internervous Plane:

• Between gluteus maximus (inferior gluteal nerve) and gluteus medius (superior gluteal nerve)
• Gluteus maximus is split in line with its fibres, not detached
• This is a TRUE internervous plane - no muscle denervation occurs

Superficial Anatomy:

• Greater trochanter - key palpable landmark
• Posterior superior iliac spine - incision curves toward this
• Gluteal fold - marks inferior extent of gluteus maximus
• Femoral shaft axis - incision follows this distally

Sciatic Nerve (CRITICAL):

• Location: 2-3cm posterior to posterior acetabular wall
• Emerges below piriformis (90%) or through piriformis (10%)
• At risk during posterior retractor placement and capsulotomy
• Protection: Hip flexed, knee flexed to relax nerve; retractor on ischium not soft tissue

Short External Rotators (Superior to Inferior):

1. Piriformis - attaches to superior greater trochanter
2. Superior gemellus
3. Obturator internus
4. Inferior gemellus
5. Quadratus femoris - most inferior, lies on lesser trochanter

Vascular Structures:

• Inferior gluteal vessels - emerge below piriformis with sciatic nerve
• Superior gluteal vessels - exit above piriformis (protected if stay below)
• Medial circumflex femoral artery - deep to quadratus femoris (supplies femoral head - already compromised by fracture)

Hip Joint Capsule:

• Thick anteriorly (iliofemoral ligament - strongest ligament in body)
• Thinner posteriorly (ischiofemoral ligament)
• Posterior capsule attaches along posterior femoral neck
• Zona orbicularis - circular fibres create collar around femoral neck

Capsulotomy Technique:

• T-capsulotomy or posterior longitudinal capsulotomy
• TAG the capsule for later repair (reduces dislocation)
• Capsule is an important posterior stabiliser

Essential Radiographs:

• AP pelvis - both hips visible for templating comparison
• Lateral hip (cross-table or shoot-through) - assess displacement
• Traction views may help assess reducibility (rarely needed)

Garden Classification:

• Grade I: Incomplete/impacted valgus fracture (stable)
• Grade II: Complete but undisplaced (stable)
• Grade III: Complete, partially displaced (varus position)
• Grade IV: Complete, fully displaced (no trabecular contact)

Templating (Contralateral Hip):

• Femoral head size (determines prosthetic head)
• Stem size and offset
• Neck cut level relative to lesser trochanter
• Leg length assessment

Target: Surgery Within 36 Hours

• ANZHFR data shows surgery >48 hours associated with increased mortality
• Delay for medical optimisation only if clear reversible issue
• Do NOT delay for minor abnormalities (mild hyponatraemia, mild anaemia)

Orthogeriatric Co-Management:

• Early geriatrician review (within 24 hours)
• Comprehensive geriatric assessment
• Delirium prevention strategies (orientation, hydration, mobilisation)
• Medication review (anticholinergics, sedatives)

Anticoagulation Management:

• Warfarin: Target INR <1.5 (Vitamin K +/- Prothrombin complex)
• DOACs: Withhold for 24-48 hours depending on renal function
• Aspirin: Continue (no increased bleeding risk in hip fracture)
• Clopidogrel: Balance bleeding vs delay - often proceed

Transfusion Threshold:

• Hb >80 g/L for most patients
• Hb >100 g/L if significant cardiac disease
• FOCUS trial: Liberal transfusion showed no benefit

Cemented vs Uncemented:

• Cemented is STANDARD for elderly hip fracture patients
• AOANJRR: Cemented 5.9% revision at 10 years vs uncemented 8.1%
• Cochrane review: Cemented associated with less pain, better mobility, fewer reoperations
• Consider uncemented only if: significant cardiac disease (BCIS risk), previous BCIS, patient request

Bipolar vs Unipolar:

• No evidence of difference in acetabular erosion, pain, or function
• Bipolar theoretically reduces acetabular wear (inner bearing moves first)
• In practice, inner bearing often seizes over time
• Most surgeons use bipolar but unipolar equally acceptable

Stem Design:

• Collared stem: Prevents subsidence, transfers load to calcar
• Polished tapered (e.g., Exeter): Subsides into cement mantle
• Composite beam (e.g., CPT): Designed for cement fixation

Dislocation (1-5%):

• Posterior approach higher risk than anterior (mitigated by enhanced repair)
• Enhanced posterior repair reduces to 1-2%
• Higher in cognitively impaired (cannot follow precautions)
• Management: Closed reduction, hip precautions, revision if recurrent

BCIS (1-2% significant, 0.1% fatal):

• Bone Cement Implantation Syndrome - emboli during cementing
• Manifests as hypotension, hypoxia, cardiovascular collapse
• Prevention: Third-generation cementing, anaesthetic communication
• Higher risk in: cardiac disease, long-stem revision, pathological fracture

Periprosthetic Fracture (1-3%):

• Intraoperative: During preparation or insertion (more common with uncemented)
• Postoperative: Falls, usually Vancouver B or C pattern
• Risk factors: Osteoporosis, uncemented stems, female sex

Infection (1-2%):

• Deep infection requires DAIR (early) or staged revision (late)
• Superficial wound infection managed with antibiotics
• Risk factors: Diabetes, immunosuppression, prolonged surgery

Mortality:

• 30-day mortality: 5-8% (Australian data)
• 1-year mortality: 20-30% (reflects frailty, not procedure)
• This is higher than elective arthroplasty - must counsel family

Medical Complications:

• Cardiac events (MI, arrhythmia): 5-10%
• Respiratory (pneumonia, ARDS): 5-10%
• Delirium: 15-40% (especially with pre-existing cognitive impairment)
• Pressure injuries: 5-10% (reduced with early surgery)
• Urinary retention/UTI: 20-30%

DVT/PE (1-3% with prophylaxis):

• Chemical prophylaxis reduces risk significantly
• Australian standard: LMWH or DOAC for 35 days
• Mechanical prophylaxis intraoperatively

Expected Outcomes:

• 60-70% return to pre-fracture mobility level
• Full weight-bearing from Day 1
• Most patients never regain full pre-fracture independence

Hip Precautions (Posterior Approach):

• Avoid hip flexion >90 degrees
• Avoid adduction past midline
• Avoid internal rotation
• Duration: 6-12 weeks (difficult in dementia)

Long-term Considerations:

• Acetabular erosion 10-20% at 10 years (groin pain, limp)
• May require conversion to THA (5-10% at 10 years)
• Many patients do not survive long enough for this to matter

HEALTH Trial (NEJM 2019):

• 1,495 patients, displaced femoral neck fractures, age >50
• THA vs hemiarthroplasty
• Primary outcome: No difference in hip function at 24 months
• Secondary outcome: THA lower reoperation rate (5.3% vs 8.3%)
• Conclusion: Both acceptable; patient selection matters

FAITH Trial (JAMA 2017):

• Sliding hip screw vs cancellous screws for femoral neck fractures
• No difference in reoperation or complications
• Internal fixation high failure rate in elderly (20-40%)

Cochrane Review (2010, updated):

• Cemented hemiarthroplasty: Less pain, better mobility, fewer reoperations
• Bipolar vs unipolar: No significant difference in outcomes

AOANJRR Annual Report 2023 - Hemiarthroplasty:

• Cemented hemiarthroplasty: 5.9% cumulative revision at 10 years
• Uncemented hemiarthroplasty: 8.1% cumulative revision at 10 years
• Conclusion: Cemented is SUPERIOR in elderly patients

ANZHFR Annual Report 2023:

• 20,300+ hip fractures in Australia annually
• Median time to surgery: 25 hours (target <36 hours)
• 68% receive surgery within 48 hours (target >80%)
• 30-day mortality: 7.1% (unchanged despite improvements in care)
• 120-day mortality: 11.2%

Key Quality Indicators:

• Orthogeriatric assessment: 62% (target 100%)
• Surgery within 48 hours: 68% (target >80%)
• Mobilisation Day 1: 82%
• Return to pre-fracture residence: 64%

Cemented vs Uncemented Meta-Analysis:

• Parker 2020: 25 RCTs, 3,077 patients
• Cemented: Less residual pain, better mobility scores
• Uncemented: Higher revision rate, more periprosthetic fractures
• BCIS: No significant difference in mortality (BCIS is real but rare)

Third-Generation Cementing:

• Restrictor, lavage, retrograde gun, pressurisation
• Achieves 2-4mm cement interdigitation into cancellous bone
• Reduces radiolucent lines and aseptic loosening
• Standard of care in modern cemented arthroplasty

Posterior vs Lateral Approach:

• Posterior: Faster, less blood loss, better abductor preservation
• Lateral (Hardinge): Lower dislocation rate, but abductor damage
• Enhanced posterior repair: Reduces dislocation to match lateral rates (1-2%)

Enhanced Posterior Repair Evidence:

• Multiple studies show dislocation reduced from 5-10% to 1-2%
• Includes capsular repair AND short external rotator reattachment
• Should be STANDARD for posterior approach hemiarthroplasty