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OrthoVellum

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Not affiliated with the Royal Australasian College of Surgeons.

Back to Operative Surgery
Trauma

Dynamic Hip Screw (DHS) for Intertrochanteric Fracture

Comprehensive surgical technique guide for dynamic hip screw fixation of intertrochanteric femur fractures for FRCS exam preparation

Core Procedure
intermediate
By OrthoVellum Medical Education Team

Reviewed by OrthoVellum Editorial Team

Orthopaedic clinicians and medical editors • Published by OrthoVellum Medical Education Team

Editorial boardMethodologyReview policyReport a correction
High Yield Overview

DYNAMIC HIP SCREW (DHS) FOR INTERTROCHANTERIC FRACTURE

Direct Lateral Approach | Core Trauma Procedure

TraumaSubspecialty
<25mmTAD Target
A1/A2.1Best Indications
60-90minDuration

Critical Must-Knows

  • Tip-Apex Distance (TAD) <25mm is the single most important predictor of success
  • DHS is a LOAD-BEARING device requiring intact medial cortex for biomechanical function
  • Centre-centre or inferior-centre lag screw position on both AP and lateral views
  • Stable patterns only: AO 31-A1, A2.1 with intact lateral wall >20mm
  • Lateral wall thickness <20mm or reverse obliquity patterns require cephalomedullary nail

Examiner's Pearls

  • "
    TAD = sum of tip-to-apex distance on AP + lateral (correct for magnification)
  • "
    Superior screw position increases cut-out risk 3-4 fold - NEVER acceptable
  • "
    Triple reaming creates smooth channel allowing lag screw sliding for dynamic compression
  • "
    Valgus reduction acceptable and often preferable - varus is biomechanically doomed
Mnemonic

TADTAD - Tip-Apex Distance Calculation

T
Tip of screw to apex on AP view (measure in mm)
A
Add tip-to-apex distance on lateral view (correct for magnification)
D
Distance total must be &lt;25mm or cut-out risk increases exponentially
Mnemonic

STABLESTABLE - DHS Indication Criteria

S
Simple fracture pattern (AO 31-A1 or A2.1)
T
Trochanter lateral wall intact (&gt;20mm thickness)
A
Adequate medial cortex for load-bearing support
B
Basilar neck NOT involved (not basicervical in young)
L
Lesser trochanter attached or minimally displaced
E
Extension subtrochanteric NOT present

Critical Danger Structures

Perforating Vessels

Branches from profunda femoris traverse vastus lateralis from posterior to anterior. Location: Throughout vastus muscle belly. Protection: Careful vastus splitting with coagulation of perforators as encountered.

Superior Gluteal Nerve

Motor supply to gluteus medius/minimus. Location: 3-5cm proximal to greater trochanter tip (safe zone below GT). Protection: Limit proximal dissection, avoid retractors above GT.

Sciatic Nerve

Major nerve posterior to hip. Location: 5cm posterior to greater trochanter, emerges below piriformis. Protection: No posterior retractor placement, avoid posterior dissection.

Femoral Vessels

Femoral artery and vein anteriorly. Location: Femoral triangle, anteromedial to femur. Protection: Strictly lateral approach, no anterior dissection beyond femoral shaft.

Primary Indications

Absolute Indications:

  • Stable intertrochanteric fractures (AO/OTA 31-A1) - the ideal DHS fracture pattern
  • Simple pertrochanteric fractures (AO/OTA 31-A2.1) with intact medial cortex and lateral wall
  • Lateral wall thickness >20mm on pre-reduction imaging (Palm criteria)
  • Basicervical femoral neck fractures in elderly with osteoporotic bone (selected cases)

Relative Indications:

  • Selected A2.2 patterns with reconstructable medial cortex
  • Patients where intramedullary device contraindicated (severe femoral bowing, narrow canal)
  • Surgeon expertise with DHS for borderline patterns

Australian Context:

  • ANZHFR 2023: 48% of intertrochanteric fractures receive DHS, 52% receive cephalomedullary nail
  • Medicare MBS item 47528: Internal fixation of intertrochanteric fracture - $1,247.55
  • LMWH or DOAC for VTE prophylaxis (enoxaparin 40mg daily or rivaroxaban 10mg daily for 35 days)

Contraindications

Absolute Contraindications:

  • Reverse obliquity patterns (AO 31-A3) - fracture line runs superomedial to inferolateral, DHS cannot resist varus collapse
  • Lateral wall thickness <20mm or comminuted - lateral wall required for barrel plate stability
  • Subtrochanteric extension - DHS cannot control long lever arm of distal fragment
  • Pathological fractures with metastatic bone disease - inadequate bone for screw purchase

Relative Contraindications:

  • Severe osteoporosis with eggshell cortex - high cut-out risk
  • Combined neck-shaft fractures - complex pattern better suited to reconstruction nail
  • Fracture in young patient (<50 years) - consider anatomic reduction ORIF if fit for longer surgery
  • Morbid obesity (BMI >40) - increased mechanical demands

Relevant Surgical Anatomy

Bony Landmarks:

  • Greater trochanter (GT) - most prominent lateral hip landmark, entry point for guide wire
  • Lesser trochanter - level of neck cut reference, attachment of iliopsoas
  • Intertrochanteric crest - joins GT to LT posteriorly, defines fracture region
  • Calcar femorale - dense medial cortex, critical for load-bearing in DHS

Femoral Neck Anatomy:

  • Normal neck-shaft angle: 125-135° (average 130°)
  • Femoral neck anteversion: 10-15° (affects guide wire rotation)
  • Trabecular architecture: Compressive trabeculae (medial), tensile trabeculae (lateral), Ward's triangle (central deficiency)
  • Cortical thickness: Medial cortex thickest (calcar), lateral thinnest

Vascular Anatomy:

  • Profunda femoris artery: Runs posterior to femur in adductor canal, gives off perforating branches
  • Perforating arteries: 3-4 branches traverse vastus lateralis from posterior to anterior
  • Medial femoral circumflex artery (MFCA): Main blood supply to femoral head - runs along posterior neck, protected by leaving quadratus femoris intact
  • Lateral femoral circumflex artery: Supplies anterolateral thigh, branches encountered during approach

Neural Anatomy:

  • Sciatic nerve: Exits pelvis below piriformis, runs posterior to hip 5cm posterior to GT, at risk with posterior retractor placement
  • Superior gluteal nerve: Exits above piriformis, 3-5cm proximal to GT tip - safe zone below GT
  • Femoral nerve: Lies anteromedial in femoral triangle, protected by strictly lateral approach
  • Lateral femoral cutaneous nerve: Exits lateral to ASIS, can be injured with anterior extension

Direct Lateral Approach

Surface Landmarks:

  • Palpate greater trochanter - most prominent lateral bony point
  • Femoral shaft axis - line from GT to lateral femoral condyle
  • Vastus ridge - palpable ridge on lateral femur distal to GT

Incision:

  • Start just distal to GT tip, extend distally along lateral femoral shaft
  • Length: 8-12cm (adjust for body habitus and plate length)
  • Orientation: Straight, parallel to femoral shaft axis

Superficial Dissection:

  1. Incise skin and subcutaneous fat to fascia lata
  2. Identify and incise fascia lata (iliotibial band) in line with skin incision
  3. Fascia lata is thick, strong layer - incise carefully to avoid muscle
  4. Retract edges to expose vastus lateralis muscle belly

Deep Dissection: Two options for vastus lateralis:

  1. SPLIT technique (preferred): Split muscle in line with fibers running obliquely from superolateral to inferomedial. Less bleeding, preserves muscle function.
  2. ELEVATE technique: Elevate muscle anteriorly off lateral intermuscular septum. More bleeding, but may give better exposure.

Control perforating vessels from profunda femoris with electrocautery as encountered.

Internervous Plane:

  • This approach is NOT a true internervous plane
  • Vastus lateralis is supplied by femoral nerve throughout its belly
  • The approach works by SPLITTING vastus lateralis in line with muscle fibers
  • This is an INTRAmuscular plane, not INTERnervous
  • Safe because splitting in fiber direction minimizes denervation

Comparison to Other Hip Approaches:

  • Posterior approach: Gluteus maximus (inf. gluteal) vs gluteus medius (sup. gluteal) - true internervous superficially
  • Anterior approach: Sartorius (femoral) vs TFL (sup. gluteal) - true internervous
  • Anterolateral (Watson-Jones): TFL vs gluteus medius - NOT internervous (both sup. gluteal)
  • Lateral (Hardinge): Splits gluteus medius - NOT internervous
  • Direct lateral (DHS): Splits vastus lateralis - NOT internervous (all femoral)

Imaging Requirements

Standard Imaging:

  • AP pelvis - shows both hips for comparison, measures neck-shaft angle
  • Lateral hip (cross-table or shoot-through) - essential for assessing posterior comminution
  • Traction view if fracture severely displaced (reduces fracture, better pattern assessment)

Advanced Imaging (When Indicated):

  • CT scan if:
    • Complex pattern or concern for lateral wall integrity
    • Occult femoral neck fracture suspected (5% have concomitant intracapsular fracture)
    • Pathological fracture requiring assessment of bone stock
  • MRI rarely indicated in elderly trauma

Fracture Classification

AO/OTA 31-A Classification:

  • 31-A1: Simple pertrochanteric (2 fragments)

    • A1.1: Along intertrochanteric line - IDEAL for DHS
    • A1.2: Through greater trochanter
    • A1.3: Below lesser trochanter

  • 31-A2: Multifragmentary pertrochanteric (>2 fragments)

    • A2.1: One intermediate fragment - DHS suitable if lateral wall intact
    • A2.2: Several intermediate fragments - NAIL preferred
    • A2.3: Extending more than 1cm below lesser trochanter - NAIL preferred

  • 31-A3: Intertrochanteric/reverse obliquity

    • A3.1: Simple oblique - NAIL MANDATORY
    • A3.2: Simple transverse - NAIL MANDATORY
    • A3.3: Wedge or comminuted - NAIL MANDATORY

Lateral Wall Assessment

Palm Criteria (Palm et al. JBJS 2007):

  • Measure lateral wall thickness on AP radiograph
  • Distance from lateral cortex to level where lag screw will sit
  • >20mm = Intact lateral wall → DHS appropriate
  • <20mm = Deficient lateral wall → High failure risk, NAIL preferred

Why Lateral Wall Matters:

  • DHS barrel plate sits on lateral cortex
  • If lateral wall fractures during surgery → implant loses buttress
  • Lateral wall fracture converts stable to unstable pattern
  • Failure rate increases from 5% to 40% with lateral wall fracture

Implant Selection

Plate Angle Selection:

  • 135° angle (standard): Most common, suits most patients
  • 150° angle: For high neck-shaft angle (>135°), or coxa valga
  • Match angle guide to plate angle selected

Plate Length:

  • 4-hole barrel plate: Standard for most fractures
  • 6-hole or longer: Consider for osteoporosis, subtrochanteric extension, comminution

Lag Screw Length:

  • Typically 85-105mm in adults
  • Measure intraoperatively to confirm (should end 5-10mm from subchondral bone)
  • Select based on guide wire measurement minus 5-10mm

Consent Discussion

Procedure-Specific Risks:

  • Cut-out (5-15%): Lag screw migration through femoral head - most common mechanical complication
  • Non-union (<5%): Higher with varus malalignment, poor medial cortex contact
  • Malunion: Varus, shortening, rotational deformity
  • AVN (<2% in extracapsular fractures - rare because blood supply preserved)
  • Infection (1-3%): Superficial or deep
  • DVT/PE (10-20% without prophylaxis, <5% with prophylaxis)
  • Need for revision surgery (5-10%)

General Risks:

  • Bleeding requiring transfusion (20-30%) - elderly patients often anemic at baseline
  • Medical complications (cardiac 5%, respiratory 5%, renal 3%, delirium 10-30%)
  • Mortality: 30-day 5-10%, 1-year 20-30% in elderly with hip fracture

Functional Outcome:

  • Most patients mobilise weight-bearing as tolerated (WBAT)
  • 50% return to pre-injury function at 1 year
  • 30% remain below baseline function at 1 year
  • Many require ongoing mobility aids (frame, stick)

Step-by-Step Technique

Step 1: Anaesthesia and Patient Positioning

Patient under general or spinal anaesthesia on fracture table. Affected leg in traction boot with longitudinal traction applied. Internal rotation 10-15 degrees to correct typical external rotation deformity of distal fragment. Perineal post well-padded and positioned lateral to genitals. Contralateral leg abducted in hemilithotomy or extended. Confirm C-arm can obtain clear AP and lateral views BEFORE draping.

Exam Pearl

Technical Tip: EXAM KEY: 'I position the patient supine on a fracture table. Longitudinal traction corrects shortening. Internal rotation 10-15° corrects the external rotation deformity typical of intertrochanteric fractures. The perineal post is well-padded and positioned LATERAL to the genitals to prevent pudendal nerve compression. I CONFIRM imaging views before prepping.'

Positioning Dangers

  • Perineal post too medial → pudendal nerve compression (numbness, impotence)
  • Excessive traction → sciatic nerve stretch, compartment syndrome
  • Lateral pelvic tilt → difficulty obtaining true AP/lateral views
  • Inadequate C-arm access → suboptimal imaging during fixation

Step 2: Closed Reduction

Apply gentle longitudinal traction and internal rotation. Check reduction on AP and lateral C-arm views. ACCEPTABLE REDUCTION CRITERIA:

  • Anatomic or slight valgus alignment (5-10°) - valgus preferred over varus
  • Restoration of medial cortical continuity (CRITICAL for DHS biomechanics)
  • No posterior sag on lateral view (common pitfall)
  • Normal or slightly increased neck-shaft angle (125-135°)
  • Rotation corrected (patella facing ceiling)

If closed reduction inadequate, use Schanz pin joystick in greater trochanter to manipulate proximal fragment. DO NOT proceed until reduction acceptable.

Exam Pearl

Technical Tip: EXAM KEY: 'I accept ANATOMIC or SLIGHT VALGUS alignment (5-10°) with restoration of medial cortical support - this is CRITICAL as DHS is a LOAD-BEARING device. The medial cortex must be in contact to share load with the implant. VARUS malalignment is NEVER acceptable as it predicts biomechanical failure. I verify NO posterior sag on lateral view.'

Reduction Pitfalls

  • VARUS malalignment is NEVER acceptable - causes DHS failure in 40% vs 5%
  • Persistent posterior sag on lateral → leads to apex posterior deformity
  • Over-distraction → prevents fracture impaction and healing
  • Loss of medial cortical contact → removes weight-bearing buttress
  • Malrotation → affects hip ROM and gait postoperatively

Step 3: Skin Incision and Superficial Dissection

Palpate greater trochanter. Make longitudinal incision 8-12cm, starting just distal to GT, extending distally along lateral femoral shaft. Incise skin and subcutaneous tissue to fascia lata. Identify and incise fascia lata (iliotibial band) in line with skin incision. Retract edges with self-retaining retractor to expose vastus lateralis muscle.

Exam Pearl

Technical Tip: EXAM KEY: 'Direct lateral approach with 8-12cm incision starting just BELOW the greater trochanter tip, extending distally. I incise through fascia lata (iliotibial band) to expose vastus lateralis. Incision length adjusted for body habitus - longer in obese patients.'

Superficial Dissection Dangers

  • Incision too proximal → enters gluteus medius (abductor weakness)
  • Incision too anterior → lateral femoral cutaneous nerve injury
  • Inadequate length → poor exposure, instrument crowding, errors

Step 4: Deep Dissection and Femoral Exposure

Two options for vastus lateralis management:

  1. SPLIT along muscle fibres (preferred - less bleeding)
  2. ELEVATE anteriorly off lateral intermuscular septum

Expose lateral femoral cortex for plate length required (minimum 8-10cm). Identify and coagulate perforating vessels from profunda femoris as encountered. Clear periosteum ONLY where plate will sit - minimize periosteal stripping.

Exam Pearl

Technical Tip: EXAM KEY: 'I prefer to SPLIT vastus lateralis in line with its muscle fibers - this minimizes bleeding and preserves motor function. I expose the lateral femoral cortex for the planned plate length. Perforating vessels from profunda femoris traverse the muscle - I control these with electrocautery before they bleed.'

Deep Dissection Dangers

  • Perforating vessels cause significant bleeding if not controlled proactively
  • Excessive periosteal stripping devascularises bone → delayed union
  • Posterior dissection risks profunda femoris artery
  • Sharp posterior retractor placement → sciatic nerve injury

Step 5: Guide Wire Insertion and Positioning

Attach angle guide (135° standard) to lateral femoral cortex at level of lesser trochanter. Entry point: junction of proximal and middle thirds of femur, at or just above lesser trochanter level. Advance guide wire under fluoroscopy toward femoral head centre.

TARGET POSITION (CRITICAL):

  • Centre-centre position in femoral head on AP view
  • Centre-centre OR inferior-centre on lateral view
  • NEVER superior position - increases cut-out 3-4 fold

Advance wire to within 5-10mm of subchondral bone. Calculate Tip-Apex Distance (TAD) at this point.

Exam Pearl

Technical Tip: EXAM KEY: 'I insert the guide wire through a 135° angle guide, aiming for CENTRE-CENTRE position in the femoral head on BOTH AP AND lateral views. INFERIOR-CENTRE on lateral is also acceptable. SUPERIOR position is NEVER acceptable as it increases cut-out risk 3-4 fold. Baumgaertner's classic paper showed TAD predicts failure - I calculate TAD at guide wire insertion and adjust before proceeding.'

Guide Wire Dangers

  • Superior placement → cut-out risk increases 3-4 fold - NEVER acceptable
  • Posterior placement → posterior perforation, AVN if damages MFCA
  • Wire too long → joint penetration
  • Wire too short → inadequate lag screw depth, poor purchase
  • Wrong angle → varus stem, malposition

Step 6: Tip-Apex Distance Calculation

Calculate TAD to confirm acceptable wire position:

  1. Measure tip-to-apex distance on AP view (in mm)
  2. Measure tip-to-apex distance on lateral view (in mm)
  3. Correct for magnification using known wire/screw diameter
  4. Sum both measurements: TAD = AP distance + Lateral distance

TARGET: TAD <25mm

  • TAD <25mm: Cut-out risk 2-5%
  • TAD 25-30mm: Cut-out risk increases
  • TAD >30mm: Cut-out risk 6-fold higher (30%+)

If TAD >25mm, REPOSITION guide wire before proceeding.

Exam Pearl

Technical Tip: EXAM KEY: 'Baumgaertner's Tip-Apex Distance is the SINGLE MOST IMPORTANT predictor of DHS success. I calculate TAD by summing the tip-to-apex distance on AP plus lateral views, correcting for magnification. TAD MUST be less than 25mm. If above 25mm, I REPOSITION the guide wire - do NOT accept suboptimal position.'

TAD Pitfalls

  • TAD >25mm is UNACCEPTABLE - reposition wire, do not proceed
  • Magnification error → calculate using known screw diameter as reference
  • Measuring to head apex, NOT to subchondral bone edge
  • TAD >30mm → cut-out risk 6-fold higher

Step 7: Triple Reaming

Perform triple reaming over guide wire to measured depth (5-10mm short of subchondral bone). Triple reaming creates a smooth, three-part channel:

  • Outer diameter for barrel plate seating
  • Middle diameter for lag screw threads
  • Inner diameter for lag screw core

This allows:

  • Easy lag screw insertion without resistance
  • Lag screw SLIDING for dynamic compression as fracture settles

Irrigate during reaming to prevent thermal necrosis. Confirm depth with gauge.

Exam Pearl

Technical Tip: EXAM KEY: 'Triple reaming is ESSENTIAL for DHS function. The three-diameter channel allows the lag screw to SLIDE within the barrel, enabling dynamic compression as the patient bears weight and the fracture impacts. This is the "dynamic" in Dynamic Hip Screw. Without proper reaming, the screw cannot slide and static load leads to failure.'

Reaming Dangers

  • Reaming too deep → subchondral perforation, joint penetration
  • Reaming too shallow → lag screw threads proud, cannot slide
  • Thermal necrosis (no irrigation) → bone death, loosening
  • Eccentric reaming → screw malposition

Step 8: Lag Screw Insertion

Select lag screw length based on measurement (typically 85-100mm). Insert over guide wire through reamed channel. Advance to within 5-10mm of subchondral bone - check with fluoroscopy.

CONFIRM FINAL POSITION:

  • Centre-centre or inferior-centre on AP view
  • Centre-centre or inferior-centre on lateral view
  • Calculate and DOCUMENT final TAD - MUST be <25mm
  • Screw threads fully within femoral head

Exam Pearl

Technical Tip: EXAM KEY: 'I insert the lag screw to within 5-10mm of subchondral bone with optimal position being CENTRE-CENTRE on both views, or INFERIOR-CENTRE on lateral. I calculate and DOCUMENT Tip-Apex Distance which MUST be less than 25mm - this is recorded in the operative note for medicolegal protection. TAD >25mm is unacceptable and requires repositioning BEFORE plate application.'

Lag Screw Dangers

  • Joint penetration → catastrophic articular damage, requires removal
  • TAD >25mm → cut-out risk unacceptable - REPOSITION before plate
  • Superior placement → cut-out 3-4x more likely
  • Screw too short → inadequate purchase, pullout

Step 9: Barrel Plate Application

Slide barrel plate over lag screw. CRITICAL: Seat plate FLUSH against lateral femoral cortex - plate must NOT be proud. Ensure plate aligned with femoral shaft axis without flexion/extension or rotation. Apply provisional fixation with one distal cortical screw.

PLATE SEATING CHECK:

  • No gap between plate and cortex
  • Plate parallel to femoral shaft
  • No rotation of plate
  • Barrel fully engaged on lag screw

Exam Pearl

Technical Tip: EXAM KEY: 'The barrel plate MUST seat FLUSH on the lateral femoral cortex. If the plate is proud (not seated), the lag screw cannot slide within the barrel - losing the "dynamic" function. I apply provisional fixation with ONE screw first, then check position on fluoroscopy before definitive fixation.'

Plate Application Dangers

  • Plate proud → lag screw cannot slide, static loading → failure
  • Plate malrotated → screw angulation, impingement
  • Plate too proximal → screws in fracture zone
  • Plate too distal → inadequate proximal fragment fixation

Step 10: Cortical Screw Fixation

Insert cortical screws through remaining plate holes achieving BICORTICAL purchase. Minimum 4 cortices of fixation distally (2 screws × 2 cortices). Consider anti-rotation screw in proximal hole above barrel for added rotational stability of femoral head. Confirm ALL screws bicortical on fluoroscopy.

SCREW PLACEMENT GOALS:

  • Bicortical purchase (30-44mm screws typical)
  • Perpendicular to plate and cortex
  • All screw tips visible on lateral view
  • No screws in fracture zone

Exam Pearl

Technical Tip: EXAM KEY: 'I achieve BICORTICAL purchase with all cortical screws - this provides maximum pullout resistance. In osteoporotic bone, I may use longer screws to engage far cortex firmly. I avoid placing screws in the fracture zone. An anti-rotation screw superiorly can improve rotational control of the femoral head fragment.'

Screw Fixation Dangers

  • Unicortical screws → inadequate fixation, plate pullout
  • Screws in fracture zone → interferes with healing, stress riser
  • Screws too long → soft tissue impingement, vessel injury
  • Stripped cortex → no purchase, consider rescue techniques

Step 11: Compression and Final Fluoroscopic Check

Remove guide wire from lag screw. Apply compression through barrel plate compression screw mechanism to engage dynamic lag effect. Release traction gradually and observe for stability.

COMPREHENSIVE FINAL CHECK:

  1. Reduction maintained (valgus acceptable, medial cortex intact)
  2. Lag screw centre-centre or inferior-centre on BOTH views
  3. TAD <25mm DOCUMENTED in operative note
  4. Screw 5-10mm from subchondral bone, NO joint penetration
  5. Plate FLUSH on lateral cortex
  6. ALL screws bicortical
  7. Rotation and length correct (compare to contralateral leg)
  8. Compression applied - fracture impacted

Exam Pearl

Technical Tip: EXAM KEY: 'My final check includes: 1) Reduction maintained - valgus acceptable, medial cortex contact. 2) Lag screw position centre-centre or inferior-centre on BOTH views. 3) TAD documented and less than 25mm. 4) No joint penetration. 5) Plate flush. 6) All screws bicortical. 7) Rotation and length satisfactory. 8) Fracture compressed. I document TAD in the operative note for medicolegal purposes.'

Critical Final Check Items

  • TAD >25mm requires repositioning - do NOT accept
  • Joint penetration requires screw exchange
  • Unrecognised malrotation causes functional impairment
  • Persistent varus predicts failure - consider conversion to nail
  • Loss of reduction at traction release → fixation inadequate

Step 12: Wound Closure and Post-operative Management

Copious irrigation with saline. Meticulous haemostasis with electrocautery. Consider drain for high-risk patients (anticoagulation, large haematoma anticipated). Repair vastus lateralis muscle if elevated. Close fascia lata with strong absorbable suture (0 or 1 Vicryl) - provides soft tissue coverage of implant. Subcutaneous closure with 2-0 absorbable. Skin with staples or subcuticular suture. Sterile dressing.

Exam Pearl

Technical Tip: EXAM KEY: 'I irrigate copiously, achieve haemostasis, and close fascia lata carefully - this layer provides important soft tissue coverage over the implant. I document blood loss and neurovascular status at closure. Post-operatively, I mobilise WBAT from Day 1 for stable fixation - early mobilisation reduces medical complications and mortality in elderly hip fracture patients.'

Closure Dangers

  • Inadequate haemostasis → haematoma → infection risk
  • Poor fascial closure → implant exposure, wound complications
  • Missed neurovascular injury → delay in management

DHS Complications: Recognition, Prevention, and Management

ComplicationRecognitionPreventionManagement
**Cut-out** (5-15%) Most common mechanical complication, lag screw migrates through femoral head superolaterallyLag screw migrates superiorly through femoral head on follow-up X-rays. Pain, inability to weight-bear, limb shortening. Usually within first 3 monthsTAD &lt;25mm (reduces risk 6-fold), centre-centre or inferior-centre position, avoid varus reduction, adequate screw purchase, appropriate patient selectionEarly (limited cut-out, bone stock adequate): Screw reposition (rarely successful) Late (significant cut-out): Salvage with arthroplasty - hemiarthroplasty or THA depending on acetabulum and patient factors
**Non-union** (&lt;5%) Failure of fracture to heal, more common with varus malalignmentPersistent fracture line &gt;6 months, pain with weight-bearing, implant failure signs (screw breakage, plate pullout)Anatomic or valgus reduction, medial cortex contact, avoid distraction, controlled impaction, stable fixationRevision fixation with bone graft if bone stock adequate and patient fit. Conversion to THA if poor bone stock or elderly
**Malunion** (5-10%) Varus deformity, shortening, external rotation most commonVarus deformity on X-ray, limb length discrepancy (shortening), external rotation with foot pointing outward, limpIntraoperative reduction assessment on BOTH AP and lateral views, compare rotation to contralateral leg, accept only anatomic or valgus reductionMild (&lt;15° varus, &lt;2cm shortening): Shoe lift, observation Severe (symptomatic): Corrective osteotomy if patient fit for surgery
**Deep Infection (PJI)** (1-3%) S. aureus most common organismWound erythema, discharge, fever, elevated CRP/ESR (CRP &gt;100 concerning). Late presentation may be indolent painPerioperative antibiotics within 60min (cefazolin 2g), sterile technique, haemostasis, minimal surgical time, soft tissue coverage of implantSuperficial: Oral antibiotics, wound care Deep: Surgical debridement, IV antibiotics 6 weeks. If implant loose: exchange or removal depending on fracture healing
**DVT/PE** (10-20% without prophylaxis) Major cause of morbidity and mortalityDVT: Calf swelling, pain, Homans sign PE: Dyspnoea, chest pain, hypoxia, tachycardia, haemodynamic instabilityChemical prophylaxis: LMWH (enoxaparin 40mg daily) or DOAC (rivaroxaban 10mg daily) for 35 days. Early mobilisation. Mechanical: TED stockings, foot pumpsDVT: Therapeutic anticoagulation (LMWH or DOAC) PE: Anticoagulation, supportive care, consider thrombolysis if massive PE. IVC filter if anticoagulation contraindicated
**Lateral Wall Fracture** (2-5%) Intraoperative or early post-operativeIntraoperative: Fracture line seen during reaming/screw insertion, loss of plate seating Postoperative: Varus collapse, loss of fixation stability on follow-up X-raysPre-operative assessment of lateral wall integrity (Palm criteria &gt;20mm), consider nail if &lt;20mm, gentle reaming techniqueIf recognised intraoperatively: Convert to cephalomedullary nail If postoperative: Revision to nail if early, arthroplasty if late or failed fixation
**Implant Failure** (&lt;5%) Plate pull-off, screw breakageSudden pain, inability to weight-bear, visible deformity. X-ray shows plate separation or screw fractureAdequate screw purchase (bicortical), appropriate implant selection, avoid excessive dynamisation, treat osteoporosisRevision fixation vs arthroplasty depending on bone quality and fracture status. Consider THA in elderly with poor bone
**Mortality** (20-30% at 1 year) Multifactorial - medical comorbidities, delirium, immobilityHigh-risk elderly population with multiple comorbidities. Frailty, cognitive impairment, poor baseline function predict worse outcomesOrthogeriatric co-management, early surgery (&lt;36-48 hours), medical optimisation, early mobilisation, DVT prophylaxis, nutrition, delirium preventionMultidisciplinary approach: Orthogeriatrics, physiotherapy, occupational therapy, social work. Advance care planning. Falls prevention. Bone health optimisation

Additional Complications

Avascular Necrosis (<2% for extracapsular fractures):

  • Rare in intertrochanteric fractures because blood supply preserved
  • Medial femoral circumflex artery runs along posterior neck - protected by leaving quadratus femoris intact
  • May occur if lag screw damages MFCA or with posterior perforation
  • Management: If symptomatic, consider arthroplasty

Nerve Injury (<1%):

  • Sciatic nerve: Posterior retractor placement, excessive traction
  • Superior gluteal nerve: Proximal dissection above GT
  • Pudendal nerve: Perineal post malposition
  • Prevention: Careful retractor placement, padded post lateral to genitals, limit traction
  • Management: Document, EMG at 3 weeks, observation (most neuropraxia recover)

Heterotopic Ossification (5-10% radiographic, 1-2% symptomatic):

  • Less common than in THA
  • Risk factors: Head injury, burns, prolonged immobilisation
  • Prevention: Not routine - consider indomethacin if high risk
  • Management: Observation if asymptomatic, excision if severe restriction

Australian Registry Data (ANZHFR 2023)

Hip Fracture Epidemiology:

  • 26,000+ hip fractures annually in Australia
  • 50% intertrochanteric, 45% intracapsular, 5% subtrochanteric
  • Mean age: 84 years for women, 80 years for men
  • Female:Male ratio 3:1

Implant Selection Trends:

  • Intertrochanteric fractures: 48% DHS, 52% cephalomedullary nail
  • Trend toward increasing nail use for all patterns
  • DHS use declining but remains appropriate for stable patterns

Timing of Surgery:

  • ANZHFR target: Surgery within 48 hours for 80% of patients
  • Current performance: 72% achieve this target
  • Delay beyond 48 hours associated with 10% increased mortality per day

30-Day Outcomes:

  • Mortality: 7-10%
  • Medical complications: Cardiac 5%, Pneumonia 6%, UTI 10%, Delirium 25%
  • Return to theatre: 2-3%

1-Year Outcomes:

  • Mortality: 20-30% (highest in first 3 months)
  • Residential care admission: 25% (previously community-dwelling)
  • Return to pre-injury function: 50%
  • Mobility aids required: 70%

Key Evidence Studies

Tip-Apex Distance (Baumgaertner et al. JBJS 1995):

  • Landmark paper defining TAD
  • Cut-out rate: 2% if TAD <25mm vs 16% if TAD >25mm
  • Superior screw position increased cut-out 3-4 fold
  • MUST KNOW for exam - cite this paper

Lateral Wall Importance (Palm et al. JBJS 2007):

  • Lateral wall thickness <20mm → failure rate 40%
  • Lateral wall thickness >20mm → failure rate 5%
  • Pre-operative CT can assess wall integrity
  • Lateral wall fracture converts stable to unstable pattern

DHS vs Nail for Stable Fractures (Cochrane Review 2010, updated 2017):

  • No significant difference in outcomes for stable A1/A2.1 fractures
  • Similar mortality, function, reoperation rates
  • DHS slightly shorter operative time and less blood loss
  • Nail has theoretical advantage of load-sharing but not borne out in stable fractures

DHS vs Nail for Unstable Fractures (Multiple RCTs):

  • Nail superior for A2.3 and A3 patterns
  • Lower failure rate with nail for unstable fractures
  • Parker 2012, Reindl 2015, Zhang 2017 meta-analyses support nail for unstable patterns

Early Surgery (Moran et al. JBJS 2005):

  • Delay beyond 48 hours increases mortality 10% per day
  • Complications increase with delay
  • Surgery within 36 hours optimal if medically cleared
  • Supports current ANZHFR 48-hour target

Orthogeriatric Co-management (Grigoryan et al. BMC Geriatr 2014):

  • Orthogeriatric care reduces mortality 20-30%
  • Reduces length of stay
  • Reduces complications (delirium, pressure injuries, infections)
  • Cost-effective intervention - standard of care in Australia

Australian Specific Guidelines

VTE Prophylaxis (NHMRC Guidelines):

  • LMWH (enoxaparin 40mg daily) or DOAC (rivaroxaban 10mg daily) for 35 days
  • Start 6-12 hours postoperatively (balance bleeding vs VTE risk)
  • Mechanical prophylaxis: TED stockings, foot pumps, early mobilisation
  • High-risk (previous VTE): Extended prophylaxis, consider IVC filter

Antibiotic Prophylaxis (eTG - Therapeutic Guidelines):

  • Cefazolin 2g IV within 60 minutes of incision
  • 4g if >120kg body weight
  • Penicillin allergy: Vancomycin 15-20mg/kg IV (max 2g)
  • Single dose sufficient - no benefit to extended prophylaxis

Medicare MBS Item Numbers:

  • 47528: Internal fixation of intertrochanteric fracture - $1,247.55
  • Includes DHS, cephalomedullary nail, or other fixation devices

ANZHFR Quality Standards:

  • Surgery within 48 hours (target 80%)
  • Orthogeriatric care (target 100%)
  • Pressure injury prevention
  • Delirium screening and prevention
  • Falls prevention and bone health assessment

Equipment and Setup

Fracture Table Setup:

  • Radiolucent fracture table (Maquet, Hana, or similar)
  • Boot traction attachment for affected limb
  • Well-padded perineal post (lateral to genitals to avoid pudendal nerve)
  • Unaffected leg in hemilithotomy or extended and abducted

C-arm Positioning:

  • C-arm enters from contralateral side, between patient's legs
  • Must obtain clear AP and lateral views of hip and proximal femur
  • Confirm imaging BEFORE prepping patient

Instrumentation:

  • DHS instrument set with guide wire, triple reamer, tap
  • 135° and 150° angle guide/jig
  • Lag screws (85-105mm range)
  • 4-hole barrel plate (135° or 150°)
  • Cortical screws (32-44mm typical)
  • Depth gauge, calibrated measuring device

Reduction Aids:

  • Schanz pin for joystick manipulation if needed
  • Bone hooks, ball spike pusher
  • Traction table controls for length and rotation

Operative Technique

Step 1: Anaesthesia and Positioning

Patient under general or spinal anaesthesia on fracture table. Affected leg in traction boot with longitudinal traction applied. Internal rotation 10-15 degrees to correct typical external rotation deformity of distal fragment. Perineal post well-padded and positioned lateral to genitals. Contralateral leg abducted in hemilithotomy or extended. Confirm C-arm can obtain clear AP and lateral views.

Exam Pearl

Exam Key: "I use a fracture table with the patient supine. Longitudinal traction corrects shortening, and internal rotation 10-15 degrees corrects the external rotation deformity of the distal fragment. The perineal post is well-padded and positioned lateral to the genitals to prevent pudendal nerve compression."

Step 2: Closed Reduction

Apply gentle longitudinal traction and internal rotation. Check reduction on AP and lateral C-arm views. ACCEPTABLE REDUCTION CRITERIA:

  • Anatomic or slight valgus alignment (5-10 degrees)
  • Restoration of medial cortical continuity (CRITICAL for DHS)
  • No posterior sag on lateral view
  • Normal or slightly increased neck-shaft angle (125-135 degrees)

If closed reduction inadequate, use Schanz pin joystick in greater trochanter to manipulate proximal fragment. Accept reduction before proceeding.

Exam Pearl

Exam Key: "I accept anatomic or slight valgus alignment with restoration of medial cortical support - this is CRITICAL as DHS is a load-bearing device. Varus malalignment is biomechanically doomed to failure. I verify no posterior sag on lateral view."

Reduction Pitfalls

  • Varus malalignment is NEVER acceptable - causes DHS failure
  • Persistent posterior sag leads to apex posterior deformity
  • Over-distraction prevents impaction and healing
  • Loss of medial cortical contact removes weight-bearing support

Step 3: Incision and Superficial Dissection

Palpate greater trochanter. Make longitudinal incision 8-12cm centred just distal to GT, extending along lateral femoral shaft. Incise skin and subcutaneous tissue. Identify and incise fascia lata (iliotibial band) in line with skin incision. Retract to expose vastus lateralis muscle.

Exam Pearl

Exam Key: "Direct lateral approach with 8-12cm incision starting just below the greater trochanter tip extending distally. I incise through fascia lata to expose vastus lateralis."

Step 4: Deep Dissection

Two options for vastus lateralis:

  1. Split along muscle fibres (less bleeding)
  2. Elevate anteriorly off lateral intermuscular septum

Expose lateral femoral cortex for plate length required. Identify and coagulate perforating vessels from profunda femoris as encountered. Clear periosteum only where plate will sit.

Deep Dissection Dangers

  • Perforating vessels cause significant bleeding if not controlled
  • Excessive periosteal stripping devascularises bone
  • Posterior dissection risks profunda femoris vessels

Step 5: Guide Wire Insertion

Attach angle guide (135° standard) to lateral femoral cortex at level of lesser trochanter. Entry point: junction of proximal and middle thirds of femur, at or just above lesser trochanter level. Advance guide wire under fluoroscopy toward femoral head.

TARGET POSITION:

  • Centre-centre OR inferior-centre on BOTH AP and lateral views
  • NEVER superior - increases cut-out 3-4 fold

Advance wire to within 5-10mm of subchondral bone. Measure and calculate Tip-Apex Distance.

Exam Pearl

Exam Key: "I insert the guide wire through a 135-degree angle guide, aiming for centre-centre or inferior-centre position in the femoral head on BOTH AP and lateral views. Superior position is NEVER acceptable as it increases cut-out risk 3-4 fold. I calculate TAD at this point."

Step 6: Triple Reaming

Perform triple reaming over guide wire to measured depth (5-10mm short of subchondral bone). Triple reaming creates smooth channel allowing:

  • Easy lag screw insertion
  • Lag screw sliding for dynamic compression

Irrigate during reaming to prevent thermal necrosis. Confirm depth with gauge.

Step 7: Lag Screw Insertion

Select lag screw length based on measurement (typically 85-100mm). Insert over guide wire through reamed channel. Advance to within 5-10mm of subchondral bone. CONFIRM:

  • Centre-centre or inferior-centre position on AP and lateral
  • Calculate final TAD - MUST be <25mm

Exam Pearl

Exam Key: "I insert the lag screw to within 5-10mm of subchondral bone with optimal position being centre-centre or inferior-centre. I calculate and document Tip-Apex Distance which MUST be less than 25mm - this is the single most important predictor of DHS success. TAD greater than 25mm is unacceptable and requires repositioning."

Step 8: Barrel Plate Application

Slide barrel plate over lag screw. Seat plate FLUSH against lateral femoral cortex - must not be proud. Ensure plate aligned with femoral shaft axis without flexion/extension or rotation. Apply provisional fixation with one distal cortical screw.

Step 9: Screw Fixation

Insert cortical screws through remaining plate holes achieving bicortical purchase. Minimum 4 cortices of fixation distally (2 screws x 2 cortices). Consider anti-rotation screw in proximal hole above barrel for added rotational stability. Confirm all screws bicortical on fluoroscopy.

Step 10: Compression and Final Check

Remove guide wire. Apply compression through barrel plate mechanism to engage dynamic lag effect. COMPREHENSIVE FINAL CHECK:

  1. Reduction maintained (valgus acceptable, medial cortex intact)
  2. Lag screw centre-centre or inferior-centre
  3. TAD <25mm documented
  4. Screw 5-10mm from subchondral bone, no joint penetration
  5. Plate flush on lateral cortex
  6. All screws bicortical
  7. Rotation and length correct (compare to contralateral)

Release traction gradually and observe for stability.

Critical Final Check Items

  • TAD >25mm requires repositioning - do NOT accept
  • Joint penetration requires screw exchange
  • Unrecognised malrotation causes functional impairment
  • Persistent varus predicts failure

Step 11: Closure

Copious irrigation with saline. Meticulous haemostasis. Consider drain for high-risk patients (anticoagulation, large haematoma). Repair vastus lateralis. Close fascia lata with strong absorbable suture (0 or 1 Vicryl) - provides soft tissue coverage of implant. Subcutaneous closure with 2-0 absorbable. Skin with staples or subcuticular suture. Sterile dressing.

Post-operative Care

Immediate Post-operative:

  • DVT prophylaxis: LMWH or NOAC (Australian standard: enoxaparin 40mg daily or rivaroxaban 10mg daily for 14-35 days)
  • Tranexamic acid reduces transfusion requirement
  • Orthogeriatric co-management for medical optimisation

Mobilisation Protocol:

  • Weight-bearing as tolerated (WBAT) from Day 1 for stable fixation
  • Sit out of bed Day 0-1
  • Stand with frame Day 1
  • Physiotherapy for gait training, transfers, ROM

Follow-up:

  • Radiographs at 2 weeks, 6 weeks, 12 weeks
  • Monitor for cut-out (typically occurs within first 3 months)
  • Fracture union expected 8-12 weeks

Hardware Removal:

  • Not routinely required
  • Consider if symptomatic (lateral thigh pain, trochanteric bursitis)

Complications

DHS Complications: Recognition, Prevention, and Management

ComplicationRecognitionPreventionManagement
**Cut-out** (5-15%)Lag screw migrates superiorly through femoral head on follow-up X-rays. Pain, inability to weight-bear, limb shorteningTAD &lt;25mm, centre-centre or inferior-centre position, avoid varus reduction, adequate screw purchaseEarly: screw reposition if bone stock adequate. Late: salvage with arthroplasty (THA or hemiarthroplasty)
**Non-union** (&lt;5%)Persistent fracture line &gt;6 months, pain with weight-bearing, implant failure signsAnatomic reduction, medial cortex contact, avoid varus, controlled impactionRevision fixation with bone graft vs conversion to THA depending on bone quality and patient factors
**Malunion** (5-10%)Varus deformity, shortening, external rotation. Limb length discrepancy, abnormal gaitIntraoperative reduction assessment on AP and lateral, compare rotation to contralateral legCorrective osteotomy if symptomatic and patient fit for surgery
**Infection** (1-3%)Wound erythema, discharge, fever, elevated inflammatory markers. Deep infection may present latePerioperative antibiotics, sterile technique, haemostasis, soft tissue coverageSuperficial: antibiotics. Deep: surgical debridement, IV antibiotics, consider implant exchange
**DVT/PE** (10-20%)Calf swelling, pain. PE: dyspnoea, chest pain, hypoxiaChemical prophylaxis (LMWH/NOAC), early mobilisation, mechanical prophylaxisAnticoagulation as per protocol, IVC filter for recurrent PE with anticoagulation contraindication
**Implant failure**Plate pull-off, screw breakage. Sudden pain, inability to weight-bearAdequate screw purchase, appropriate implant selection, avoid excessive dynamisationRevision fixation vs arthroplasty depending on bone quality and fracture healing
**Lateral wall fracture**Intraoperative: fracture during reaming/screw insertion. Postoperative: loss of fixation stabilityPre-operative assessment of lateral wall integrity, consider nail if &lt;20mmConvert to cephalomedullary nail if occurs intraoperatively
**Mortality** (20-30% at 1 year)High-risk elderly population with multiple comorbiditiesOrthogeriatric co-management, early surgery (&lt;36-48 hours), medical optimisationMultidisciplinary approach, advance care planning

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOStandard

EXAMINER

"An 82-year-old woman falls at home and presents with a shortened, externally rotated right leg. X-rays show an intertrochanteric fracture. How would you manage her?"

EXCEPTIONAL ANSWER
I would manage this elderly patient with a hip fracture using a multidisciplinary approach prioritising early surgery. Initial assessment includes ATLS principles, analgesia with fascia iliaca block, and resuscitation. I would obtain AP pelvis and lateral hip radiographs to classify the fracture using the AO/OTA system. For pre-operative optimisation, I would involve orthogeriatrics for medical optimisation including anticoagulation reversal if needed. Current evidence supports surgery within 36-48 hours as delay beyond this increases mortality by 10% per day. Regarding surgical planning, if this is a stable pattern (A1 or A2.1) with intact lateral wall greater than 20mm and intact medial cortex, I would use a Dynamic Hip Screw. If unstable features are present including reverse obliquity, lateral wall compromise, or subtrochanteric extension, I would use a cephalomedullary nail instead. For DHS technique, I would position the patient supine on a fracture table with traction. My closed reduction target is anatomic or slight valgus with medial cortex contact. I would use a direct lateral approach, insert the lag screw to centre-centre or inferior-centre position with Tip-Apex Distance less than 25mm. Post-operatively, I would mobilise weight-bearing as tolerated from Day 1 with DVT prophylaxis.
KEY POINTS TO SCORE
Early surgery within 36-48 hours reduces mortality
Stable patterns (A1, A2.1) with intact lateral wall suit DHS
TAD &lt;25mm is the single most important technical factor
Orthogeriatric co-management improves outcomes
COMMON TRAPS
✗Delaying surgery for medical optimisation beyond 48 hours
✗Using DHS for unstable patterns (reverse obliquity, lateral wall loss)
✗Accepting varus reduction or TAD &gt;25mm
✗Forgetting DVT prophylaxis
LIKELY FOLLOW-UPS
"How would you manage if the patient is on warfarin with INR 3.2?"
VIVA SCENARIOStandard

EXAMINER

"Explain the biomechanical difference between a DHS and a cephalomedullary nail for intertrochanteric fractures."

EXCEPTIONAL ANSWER
The fundamental difference is that DHS is a LOAD-BEARING device while a cephalomedullary nail is a LOAD-SHARING device. The DHS sits on the lateral femoral cortex and transmits load directly through the implant. This creates a longer moment arm from the mechanical axis of the limb to the plate, generating higher bending forces on the construct. The DHS relies on intact medial cortex to provide compressive support. The lag screw allows controlled sliding for fracture impaction and compression. When medial cortex is intact, the bone bears significant load and the implant provides stability during healing. The cephalomedullary nail sits within the medullary canal, close to the mechanical axis. This creates a shorter moment arm with lower bending forces on the implant. The nail acts as an internal buttress, sharing load with the bone rather than bearing it entirely. The design provides better rotational control and resists varus collapse even without intact medial cortex. Clinical implications are that DHS works excellently for stable patterns where medial cortex is intact, but fails when medial support is absent. The nail is preferred for unstable patterns including reverse obliquity where the fracture line runs from superomedial to inferolateral, lateral wall deficiency less than 20mm, subtrochanteric extension, and significant medial comminution. Evidence from multiple RCTs including the Cochrane review shows equivalent outcomes for stable fractures, but superior outcomes with nailing for unstable patterns.
KEY POINTS TO SCORE
DHS is load-bearing, requiring intact medial cortex
Nail is load-sharing with shorter moment arm
Stable patterns: either device appropriate
Unstable patterns: nail superior
COMMON TRAPS
✗Describing DHS as load-sharing
✗Not understanding importance of moment arm
✗Using DHS for unstable patterns based on surgeon preference alone
LIKELY FOLLOW-UPS
"What is the lateral wall and why is it important in implant selection?"
VIVA SCENARIOStandard

EXAMINER

"At 6-week follow-up, your DHS patient has increasing groin pain and cannot weight-bear. What is your differential and management?"

EXCEPTIONAL ANSWER
My primary concern is lag screw cut-out, which is the most common mechanical complication of DHS occurring in 5-15% of cases. My clinical assessment would evaluate pain character and location, ability to weight-bear, limb length and rotation, and neurovascular status. On examination, I would look for limb shortening suggesting implant failure, external rotation deformity, and inability to straight leg raise. Imaging would include AP pelvis and lateral hip radiographs. I would assess for lag screw position change, specifically superolateral migration indicating cut-out. I would look for fracture displacement or collapse, implant failure such as screw breakage or plate pull-off, and signs of infection or AVN. If cut-out is confirmed, management depends on the extent of cut-out and remaining bone stock. For early or partial cut-out with adequate bone stock, revision DHS with longer lag screw in better position may be attempted, though success rates are low. For complete cut-out or poor bone stock, conversion to arthroplasty is indicated. In the elderly, I would typically perform cemented hemiarthroplasty or total hip arthroplasty depending on acetabular status and patient activity level. Prevention is key. TAD greater than 25mm at index surgery has 6-fold higher cut-out rate. Superior screw position increases risk 3-4 fold. Varus malreduction predisposes to failure. This emphasises the importance of meticulous technique at the index procedure.
KEY POINTS TO SCORE
Cut-out is most common mechanical failure (5-15%)
Assess with radiographs comparing to post-op films
Salvage options: revision fixation vs arthroplasty
Prevention: TAD &lt;25mm, centre-centre position, avoid varus
COMMON TRAPS
✗Not obtaining imaging immediately
✗Attempting revision fixation with poor bone stock
✗Failing to recognise infection as alternative diagnosis
LIKELY FOLLOW-UPS
"How would you calculate Tip-Apex Distance and what is the target?"

Dynamic Hip Screw (DHS) - Exam Summary

High-Yield Exam Summary

Indications

  • •Stable intertrochanteric fractures: AO 31-A1 (ideal), A2.1 (suitable)
  • •Lateral wall INTACT (&gt;20mm on AP radiograph - Palm criteria)
  • •Medial cortex intact or reconstructable (required for load-bearing)
  • •NOT for: Reverse obliquity (A3), subtrochanteric extension, lateral wall &lt;20mm, pathological fractures

Key Anatomy

  • •Direct lateral approach - splits vastus lateralis (NOT internervous - all femoral nerve supply)
  • •Perforating vessels from profunda femoris traverse vastus lateralis - control with cautery
  • •Sciatic nerve 5cm posterior to GT - protect with hip flexion, avoid posterior retractors
  • •Superior gluteal nerve 3-5cm proximal to GT tip - safe zone is below GT

Critical Technical Points

  • •TAD &lt;25mm (Baumgaertner): AP distance + Lateral distance, corrected for magnification
  • •Centre-centre OR inferior-centre position on BOTH AP and lateral views
  • •NEVER superior position - increases cut-out 3-4 fold
  • •Valgus reduction acceptable and preferred - VARUS is NEVER acceptable (40% failure rate)
  • •Triple reaming creates sliding channel - essential for dynamic compression

DHS vs Nail Decision

  • •DHS is LOAD-BEARING device - requires intact medial cortex for buttress
  • •Nail is LOAD-SHARING device - works even without medial cortex support
  • •DHS: Stable patterns (A1, A2.1), lateral wall &gt;20mm intact
  • •Nail: Reverse obliquity (A3), lateral wall &lt;20mm, subtrochanteric extension, unstable A2.2-3
  • •Cochrane: Equivalent outcomes for stable fractures, nail superior for unstable

Complications

  • •Cut-out (5-15%): Most common - prevented by TAD &lt;25mm, centre-centre position, avoid varus
  • •Non-union (&lt;5%): Requires medial cortex contact, avoid distraction
  • •Lateral wall fracture (2-5%): Converts stable to unstable - needs nail conversion
  • •DVT/PE (10-20% without prophylaxis): LMWH/DOAC for 35 days (NHMRC)
  • •Mortality: 30-day 7-10%, 1-year 20-30% in elderly

Post-op Protocol

  • •WBAT from Day 1 for stable fixation - early mobilisation reduces mortality
  • •VTE prophylaxis: Enoxaparin 40mg daily OR rivaroxaban 10mg daily for 35 days
  • •Orthogeriatric co-management reduces mortality 20-30%
  • •Follow-up X-rays: 2 weeks, 6 weeks, 12 weeks - monitor for cut-out
  • •Fracture union expected 8-12 weeks

Australian Context

  • •ANZHFR 2023: 26,000+ hip fractures/year, 48% DHS, 52% cephalomedullary nail
  • •Target surgery &lt;48 hours (80% target, 72% achieving) - 10% mortality increase per day delay
  • •Medicare MBS 47528: Internal fixation intertrochanteric fracture - $1,247.55
  • •eTG antibiotics: Cefazolin 2g IV within 60 minutes of incision

Exam Tips

  • •MUST mention: TAD &lt;25mm (Baumgaertner 1995), load-bearing device, medial cortex critical, lateral wall assessment (Palm 2007)
  • •Common question: 'DHS vs nail?' - Answer: DHS for stable (A1/A2.1) + lateral wall &gt;20mm, nail for unstable patterns
  • •Biomechanics: DHS has longer moment arm (lateral plate) → higher bending forces → needs medial cortex buttress
  • •Traps: Don't accept varus reduction, don't accept TAD &gt;25mm, don't use DHS for reverse obliquity

References

  1. Baumgaertner MR, Curtin SL, Lindskog DM, Keggi JM. The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone Joint Surg Am. 1995;77(7):1058-1064.

  2. Palm H, Jacobsen S, Sonne-Holm S, Gebuhr P. Integrity of the lateral femoral wall in intertrochanteric hip fractures: an important predictor of reoperation. J Bone Joint Surg Am. 2007;89(3):470-475.

  3. Parker MJ, Handoll HH. Gamma and other cephalocondylic intramedullary nails versus extramedullary implants for extracapsular hip fractures in adults. Cochrane Database Syst Rev. 2010;(9):CD000093.

  4. Anglen JO, Weinstein JN. Nail or plate fixation of intertrochanteric hip fractures: changing pattern of practice. A review of the American Board of Orthopaedic Surgery database. J Bone Joint Surg Am. 2008;90(4):700-707.

  5. Australian and New Zealand Hip Fracture Registry (ANZHFR). Annual Report 2023. Hip fracture care in Australia and New Zealand.

  6. NICE Guideline NG124. Hip fracture: management. National Institute for Health and Care Excellence. 2017 (updated 2023).

  7. Moran CG, Wenn RT, Sikand M, Taylor AM. Early mortality after hip fracture: is delay before surgery important? J Bone Joint Surg Am. 2005;87(3):483-489.

  8. Kanis JA, Johnell O, Oden A, et al. The risk and burden of vertebral fractures in Sweden. Osteoporos Int. 2004;15(1):20-26.

  9. Simmermacher RK, Ljungqvist J, Bail H, et al. The new proximal femoral nail antirotation (PFNA) in daily practice: results of a multicentre clinical study. Injury. 2008;39(8):932-939.

  10. Griffin XL, Parsons N, Achten J, et al. Recovery of health-related quality of life in a United Kingdom hip fracture population. Bone Joint J. 2015;97-B(3):372-382.

Quick Stats
Complexityintermediate
Reading Time50 min
Updated2025-12-25
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