High Yield Overview

HEMIARTHROPLASTY FOR FEMORAL NECK FRACTURE

Posterior Approach | Core Trauma Procedure

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CEMENTCEMENT - Third-Generation Cementing Technique

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HEMIHEMI - Hemiarthroplasty vs THA Decision

Critical Danger Structures - Posterior Approach

Sciatic Nerve

Major danger in posterior approach. Location: 2-3cm posterior to posterior acetabular wall, emerges below piriformis. Risk: 0.5-2% transient injury. Protection: Hip flexed, knee flexed to relax nerve, avoid excessive retraction posteriorly.

Inferior Gluteal Vessels

Emerge below piriformis with sciatic nerve. Location: Inferior to piriformis, course to gluteus maximus. Protection: Stay within safe zone above piriformis or clearly below with visualisation.

Superior Gluteal Nerve

Motor to gluteus medius/minimus. Location: Exits greater sciatic notch 3-5cm above GT tip. Protection: Never extend incision or dissection more than 5cm proximal to GT tip.

Femoral Vessels

Anteromedial to hip joint. Location: Femoral triangle, 4-5cm anterior to capsule. Protection: Anterior retractor on bone only, never slide medially into soft tissue.

Primary Indications

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)

Exam Pearl

Exam Key: "The classic hemiarthroplasty patient is elderly (>75), has dementia or limited mobility, and presents with a displaced intracapsular fracture. The HEALTH trial showed no functional difference vs THA, but hemiarthroplasty is faster, simpler, and appropriate for patients unlikely to survive long enough to develop acetabular erosion."

THA Preferred Over Hemiarthroplasty If

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)

Decision-Making Framework

HEALTH Trial Key Finding: No difference in hip function at 24 months, but THA had lower reoperation rate (5.3% vs 8.3%). Use shared decision-making with patient/family considering pre-injury function, cognitive status, life expectancy, and patient preferences.

Contraindications

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)

Equipment and Setup

Patient Positioning:

Lateral decubitus position (posterior approach)
Beanbag or dedicated hip positioner
Affected side up
Axillary roll for brachial plexus protection
Lower leg flexed, upper leg supported

Equipment:

Hemiarthroplasty system (modular or monoblock)
Cemented stem (polished tapered e.g., Exeter, or composite beam)
Bipolar or unipolar heads (sizes 38-58mm typically)
Head sizing gauge
Third-generation cementing equipment: restrictor, cement gun, pressuriser
Pulsatile lavage system
Long-handled retractors (Hohmann, Charnley)

Cement Preparation:

High-viscosity cement (Simplex P, Palacos)
Vacuum mixing system (reduces porosity)
Cement gun with long nozzle
Restrictor (polyethylene or bone plug)
Proximal pressuriser

Operative Technique - Posterior Approach

Step 1: Positioning and Preparation

Position patient in lateral decubitus with beanbag. Affected hip uppermost. Prep from iliac crest to below knee. Drape to allow limb manipulation. Ensure adequate padding of bony prominences. Confirm antibiotic prophylaxis administered (Cefazolin 2g IV within 60 minutes of incision).

Exam Pearl

Exam Key: "I position the patient lateral decubitus with the affected hip up. The beanbag secures the pelvis. I ensure an axillary roll is placed to protect the brachial plexus. The whole limb is prepped and draped free to allow manipulation during the procedure."

Pressure Point Protection

Check: Axillary roll (brachial plexus), head position (facial pressure), fibular head (common peroneal nerve), medial/lateral malleoli, genitalia (males). Document all padding before draping. Elderly patients with thin skin are particularly vulnerable.

Step 2: Incision and Superficial Dissection

Curvilinear incision centred on greater trochanter, extending 8-10cm distally along femoral shaft and curving 6-8cm proximally toward PSIS. Incise skin and subcutaneous tissue. Identify and incise fascia lata in line with incision. Split gluteus maximus along its fibres (internervous plane - superior gluteal nerve above, inferior gluteal nerve below).

Exam Pearl

Exam Key: "I make a curvilinear incision centred on the greater trochanter. After incising fascia lata, I split gluteus maximus in line with its fibres. This is a true internervous plane with superior gluteal nerve above and inferior gluteal nerve below."

Superior Gluteal Nerve Safe Zone

Never extend proximal dissection more than 5cm above greater trochanter tip. The superior gluteal nerve runs on deep surface of gluteus medius - damage causes abductor weakness and Trendelenburg gait.

Step 3: Identification of Short External Rotators

Retract gluteus maximus to expose short external rotators. From superior to inferior: piriformis, gemelli (superior and inferior with obturator internus between), quadratus femoris. The sciatic nerve lies posterior to these structures. Place posterior retractor carefully on ischium, NOT in soft tissues.

Exam Pearl

Exam Key: "After retracting gluteus maximus, I identify the short external rotators from superior to inferior: piriformis, superior gemellus, obturator internus, inferior gemellus, and quadratus femoris. I palpate for the sciatic nerve which lies posterior to these muscles before placing any retractors."

Sciatic Nerve Protection

Visualise or palpate sciatic nerve before placing retractors
Keep hip flexed and knee flexed to relax nerve
Posterior retractor on BONE (ischium) not soft tissue
Limit retraction time to reduce neuropraxia risk

Step 4: Capsulotomy and Dislocation

Tag and detach short external rotators (piriformis and conjoint tendon) from their femoral insertion - preserve for later repair. Perform T-capsulotomy or posterior capsulotomy. Internally rotate and flex hip to dislocate. May need to lever femoral head out with bone hook. The fractured head typically remains in acetabulum attached to ligamentum teres.

Exam Pearl

Exam Key: "I tag and detach piriformis and conjoint tendon from their femoral insertion, preserving them for repair. I perform a T-shaped capsulotomy, then internally rotate and flex the hip to dislocate. The femoral head is usually in the acetabulum still attached to the ligamentum teres."

Tagging for Enhanced Repair

ALWAYS tag the capsule and short external rotators with stay sutures before detaching. Without tags, accurate anatomical repair is impossible. Enhanced repair reduces dislocation from 5-10% to 1-2% - worth the extra minute.

Step 5: Femoral Head Removal and Sizing

Extract femoral head using corkscrew or bone hook. Measure head diameter with sizing gauge - typically 38-58mm (most commonly 46-50mm). This determines prosthetic head size. Examine acetabulum for pre-existing arthritis, cartilage damage, or acetabular protrusion.

Exam Pearl

Exam Key: "I remove the femoral head and measure it with the sizing gauge. This directly determines my prosthetic head size. I inspect the acetabulum - if there is significant pre-existing arthritis, I would consider converting to total hip arthroplasty."

Acetabular Assessment

Carefully inspect acetabulum for: 1) Pre-existing OA (exposed bone, osteophytes) - consider THA conversion. 2) Rheumatoid protrusion - may need THA. 3) Normal cartilage - proceed with hemiarthroplasty. This decision point should be discussed with patient/family pre-operatively.

Step 6: Femoral Neck Osteotomy

Cut femoral neck at appropriate level for implant system. Typically 1-1.5cm above lesser trochanter (or as per templating). Preserve calcar femorale for collar seating. Use oscillating saw with care to protect soft tissues. Remove remaining neck bone with rongeurs if needed.

Exam Pearl

Exam Key: "I use the templated neck cut level, typically 1-1.5cm above the lesser trochanter. I protect soft tissues with retractors and use the oscillating saw with copious irrigation. The cut should be perpendicular to the femoral neck axis and preserve the calcar for collar support."

Neck Cut Level Critical

Too high: Insufficient calcar support for collar, stem subsidence risk
Too low: Risk of calcar fracture, inadequate stem insertion, intraoperative fracture
Always template pre-operatively and confirm level matches plan

Step 7: Femoral Canal Preparation

Insert box chisel or starter awl to open medullary canal - aim laterally to avoid varus. Use T-handle reamer to enter canal in correct alignment. Progressively ream or broach to appropriate size. Maintain 10-15 degrees of anteversion matching native femoral version. Avoid varus positioning of stem. Check rotational alignment frequently.

Exam Pearl

Exam Key: "I open the canal with the box chisel, aiming lateral to avoid varus. I broach sequentially to the templated size, maintaining 10-15 degrees of anteversion matching native femoral version. The broach should be stable with no toggle."

Avoiding Varus and Periprosthetic Fracture

Start lateral to avoid varus - varus positioning increases fracture risk and leads to poor outcomes
Ream/broach sequentially - never skip sizes
If resistance encountered, check alignment before forcing
Any crack heard = STOP and assess for fracture (may need cables/cerclage)

Step 8: Trial Reduction

Insert trial stem with trial head matching measured size. Reduce hip and assess:

Stability in flexion-internal rotation (posterior approach prone)
Stability in extension-external rotation (anterior approach prone)
Leg length (compare to contralateral with knees together, heels level)
Soft tissue tension and impingement (should require moderate force to dislocate)

Adjust head/neck offset if modular system allows. Document trial stability for operative note.

Exam Pearl

Exam Key: "During trial reduction I assess: 1) Stability - particularly in flexion/internal rotation for posterior approach (should require at least 90° flexion, 45° IR to dislocate), 2) Leg length - knees together, heels level comparing to contralateral, 3) Soft tissue tension - moderate shuck test, 4) Range of motion without impingement."

Stability Assessment Critical

If unstable during trial: Consider larger head (increases jump distance), different offset (increases tension), or accept that patient needs strict hip precautions. Do NOT proceed to final implantation without addressing instability. Document findings.

Step 9: Third-Generation Cementing Technique

For cemented hemiarthroplasty (standard in elderly):

Restrictor Placement: Insert cement restrictor 2cm distal to planned stem tip
Pulsatile Lavage: Thoroughly wash canal with jet lavage to remove debris and fat
Dry Canal: Pack with swabs, use suction to achieve dry canal
Mix Cement: Vacuum-mix high-viscosity cement to doughy phase
Retrograde Filling: Apply cement with gun from restrictor proximally
Pressurisation: Maintain digital or mechanical pressure during filling
Stem Insertion: Insert stem slowly with controlled pressure
Maintain Pressure: Continue pressurising around stem until cement cured

Exam Pearl

Exam Key: "I use third-generation cementing technique. First, I place a restrictor 2cm distal to the stem tip. I lavage the canal with pulsatile irrigation and dry it thoroughly. I mix high-viscosity cement in a vacuum system and apply it retrograde with a cement gun. I maintain pressurisation during insertion and until the cement fully cures. This achieves optimal cement interdigitation of 2-4mm."

BCIS Prevention

Communicate with anaesthetist before cementing
Pulsatile lavage removes fat and debris reducing emboli
Slow, controlled stem insertion reduces intramedullary pressure
Have vasopressors and resuscitation ready
Consider uncemented in patients with severe cardiac disease

Step 10: Final Implantation

Insert definitive stem and head. For bipolar: assemble inner head to stem, then outer shell (confirm locking mechanism engaged). For unipolar: single head component. Reduce hip and confirm stability with same tests as trial. Check leg length. Document final implant sizes including stem, head diameter, and neck length.

Exam Pearl

Exam Key: "After cementing, I insert the definitive stem maintaining position until cement fully cured. I assemble the head (inner head to stem, then outer bipolar shell if used). I confirm the locking mechanism is engaged, reduce the hip, and repeat my stability assessment. I document all component sizes."

Final Component Verification

Before closing: 1) Confirm head is fully seated on taper (visual and tactile check), 2) Bipolar shell locked to inner head (audible/visual click), 3) Stability confirmed same as trial, 4) All swabs and instruments counted correct. Never close without confirming head assembly.

Step 11: Posterior Capsular Repair

Repair posterior capsule with strong absorbable or non-absorbable suture (e.g., No. 2 Ethibond or FiberWire). Reattach short external rotators (piriformis, conjoint tendon) to their femoral insertion through drill holes or trans-osseous technique. This enhanced soft tissue repair reduces dislocation rate from 5-10% to 1-2%.

Exam Pearl

Exam Key: "I perform enhanced posterior repair which is ESSENTIAL for reducing dislocation. I repair the capsule first, then reattach the short external rotators through drill holes in the greater trochanter using strong non-absorbable suture. This reduces dislocation from 5-10% to 1-2%."

Enhanced Repair is Mandatory

Enhanced posterior repair should be STANDARD OF CARE for posterior approach hemiarthroplasty. Evidence strongly supports reduced dislocation (from 5-10% to 1-2%). This includes: 1) Capsular repair, 2) Short external rotator reattachment through bone. Never skip this step.

Step 12: Closure

Copious irrigation (at least 1-2L saline). Meticulous haemostasis. Optional drain (controversial - I use based on bleeding/anticoagulation). Close fascia lata over gluteus maximus with strong absorbable suture (e.g., 0 Vicryl). Subcutaneous layer with absorbable suture. Skin with staples or subcuticular suture. Sterile, waterproof dressing. Post-operative radiograph in recovery.

Exam Pearl

Exam Key: "I perform copious irrigation (1-2 litres) and meticulous haemostasis. I close fascia lata first as this is the strength layer (0 Vicryl). I may use a drain depending on bleeding. Subcutaneous closure reduces dead space. I use either staples or subcuticular suture for skin and apply a waterproof dressing."

Closure Checklist Before Leaving Theatre

Final swab and instrument count CORRECT, 2) Post-operative X-ray ordered, 3) Implant details documented (sticker in notes), 4) VTE prophylaxis prescribed, 5) Antibiotics discontinued (single dose unless specific indication), 6) Weight-bearing status documented. Never leave theatre without X-ray arranged.

Post-operative Care

Immediate Post-operative:

Full weight-bearing as tolerated from Day 1
DVT prophylaxis: LMWH or DOAC for 35 days (Australian standard)
Tranexamic acid if not contraindicated
Orthogeriatric co-management for medical issues

Mobilisation:

Sit out of bed Day 0-1
Stand and walk with frame Day 1
Physiotherapy for gait training, stairs, transfers
Hip precautions for 6-12 weeks (posterior approach): avoid flexion >90 degrees, adduction beyond midline, internal rotation

Follow-up:

Radiograph before discharge
Wound check at 2 weeks
Review at 6 weeks with radiographs
Further follow-up only if symptomatic

Red Flags:

Increasing pain after initial improvement (infection, dislocation)
Wound discharge or erythema
Fever
Inability to weight-bear

Complications

Hemiarthroplasty Complications: Recognition, Prevention, and Management

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"An 85-year-old woman with a background of dementia falls in her nursing home. Radiographs show a displaced intracapsular femoral neck fracture (Garden IV). How would you manage her?"

EXCEPTIONAL ANSWER

This elderly patient with dementia and a displaced intracapsular fracture is a classic indication for hemiarthroplasty rather than internal fixation or THA. I would manage her with a multidisciplinary approach. Initial management includes analgesia with fascia iliaca block, resuscitation, and medical optimisation. I would involve orthogeriatrics early and aim for surgery within 36 hours as delay increases mortality. Regarding implant choice, I would perform a cemented hemiarthroplasty. Cemented is preferred as the AOANJRR shows lower revision rate at 10 years (5.9% vs 8.1% for uncemented). Her dementia makes THA less suitable due to compliance with precautions and the additional acetabular component offers no benefit given limited life expectancy. For technique, I would use a posterior approach with enhanced soft tissue repair including posterior capsule and short external rotators reattachment. This reduces dislocation from 5-10% to 1-2%. I would use third-generation cementing with restrictor, lavage, retrograde gun, and pressurisation. Regarding head choice, bipolar versus unipolar has no proven difference in outcomes. I would use a modular stem with collar that sits on the calcar. Post-operatively, she can weight-bear fully from Day 1. Hip precautions may be difficult given dementia. DVT prophylaxis for 35 days, orthogeriatric co-management, and discharge planning to nursing home with physiotherapy.

VIVA SCENARIOStandard

EXAMINER

"During cementing of a hemiarthroplasty, the patient becomes hypotensive and oxygen saturations drop. What is happening and how do you manage it?"

EXCEPTIONAL ANSWER

This is Bone Cement Implantation Syndrome (BCIS), a potentially life-threatening complication occurring during or shortly after cementing. It results from embolisation of fat, marrow, and cement particles into the pulmonary circulation. For immediate management, I would stop surgery if ongoing and inform the anaesthetist clearly that this is a cement reaction. Management includes 100% oxygen via bag-mask or increase FiO2, IV fluid boluses for hypotension, vasopressors such as metaraminol or noradrenaline as needed, and CPR if cardiac arrest occurs. The Donaldson classification categorises severity. Grade 1 is hypoxia (SpO2 less than 94%) or hypotension (SBP fall greater than 20%). Grade 2 involves hypoxia and hypotension with decreased consciousness. Grade 3 is cardiovascular collapse requiring CPR. Prevention is key for future cases. Third-generation cementing reduces risk through pulsatile lavage to remove fat and debris, cement restrictor to reduce pressure, slow controlled stem insertion, and communication with anaesthetist before cementing. Consider uncemented implants in patients with severe cardiac disease, pulmonary hypertension, or previous BCIS. Regarding risk factors, this patient is elderly and has a fracture with exposed medullary canal which increases risk. Other risk factors include pre-existing cardiopulmonary disease, ASA 3-4, long-stem revision arthroplasty, and metastatic disease. The incidence is 1-2% significant BCIS with approximately 0.1% fatal. This emphasises the importance of anaesthetic communication and preparation before cementing.

VIVA SCENARIOStandard

EXAMINER

"How would you counsel a patient's family regarding the choice between hemiarthroplasty and total hip arthroplasty for a displaced femoral neck fracture?"

EXCEPTIONAL ANSWER

The choice between hemiarthroplasty and THA depends on patient factors including activity level, cognitive status, and life expectancy. Regarding the evidence, the HEALTH trial was a large multicentre RCT comparing THA and hemiarthroplasty for displaced femoral neck fractures. At 24 months, there was no difference in hip function scores. However, THA had a lower reoperation rate at 5.3% versus 8.3%, and dislocation rates were similar at approximately 4%. Hemiarthroplasty is preferred in several situations. These include elderly patients over 80 years, low-demand patients who are walker or frame-dependent, patients with cognitive impairment as compliance with hip precautions is difficult, patients with limited life expectancy under 5 years, and when shorter operative time is advantageous in medically frail patients. THA is preferred in other situations. These include active patients with independent community ambulation, cognitively intact patients who can comply with precautions, younger patients aged 65-75 years with good life expectancy, and patients with pre-existing acetabular arthritis or inflammatory arthropathy. For specific considerations in this case, I would ask about pre-fracture mobility and function, cognitive status, comorbidities and life expectancy, and patient and family expectations. Regarding risks common to both, mortality at one year is 20-30% as this reflects the frailty of the population rather than procedure choice. Dislocation rates are similar at 3-5%, and infection rates are similar at 1-2%. In practical terms, hemiarthroplasty is simpler, faster, and avoids acetabular preparation. The main long-term concern is acetabular erosion requiring conversion to THA in 10-20% at 10 years, but many patients do not survive this long.