import { ComparisonTable, ContentSection, EvidenceCard, ExamCheatSheet, ExamPearl, ExamWarning, InfoCard, InfoCardGrid, MedicalImage, MnemonicCard, OnePagerSummary, SafetyAlert, Tab, Tabs, Timeline, TimelineItem, VivaScenario, VivaScenarioSection } from '@/components/mdx' {/* SECTION 1: ONE-PAGER SUMMARY */} {/* SECTION 2: EXAM WARNING */} **Both TFL and gluteus medius** are supplied by the superior gluteal nerve. This is not a true internervous plane - muscle splitting is required. Minimize denervation by splitting at musculotendinous junction. The **superior gluteal nerve exits the pelvis** 5cm proximal to the greater trochanter. Dissection beyond this risks **permanent abductor paralysis**. Always measure from GT before proximal extension. Meticulous **repair of gluteus medius** back to trochanter is critical. Poor repair causes Trendelenburg gait. Use non-absorbable suture through bone tunnels or repair to vastus ridge. **Lower dislocation risk** (3%) compared to posterior approach (5-7%) but **higher abductor weakness**. Stability is excellent but gait may be compromised if poor repair or nerve injury. {/* SECTION 2.5: QUICK DECISION GUIDE */} {/* SECTION 3: MNEMONICS */} {/* SECTION 4: OVERVIEW */} **Historical Background:** The direct lateral approach to the hip was originally described by **McFarland and Osborne** in 1954, and later modified by **Hardinge in 1982**. Hardinge's modification specifically addressed the anterior portion of gluteus medius, splitting it at the musculotendinous junction to minimize denervation while providing excellent exposure. **Evolution of the approach:** - 1954: McFarland and Osborne describe transgluteal approach - 1982: Hardinge publishes seminal modification with GM split technique - 1990s-2000s: Becomes dominant approach in Australia and UK - 2010s: DAA gains popularity but direct lateral remains common **Current status:** The Hardinge direct lateral approach is the **most commonly used THA approach in Australia** (approximately 40% of primary THA per AOANJRR). It offers excellent stability with lower dislocation rates than posterior approach, though at the cost of potential abductor mechanism disruption. **Why this approach matters:** - Most common approach nationally - essential for Orthopaedic exam - Lower dislocation rate than posterior approach - Good femoral and acetabular exposure - Familiar to most Australian orthopaedic surgeons - Requires understanding of abductor protection and repair {/* SECTION 10: INDICATIONS (Moved) */} ### Indications **Primary indications:** - Primary total hip arthroplasty - Hemiarthroplasty (femoral neck fractures) - Hip resurfacing arthroplasty - Simple revision THA (liner exchange, head/neck change) **Advantages:** - Lower dislocation rate compared to posterior approach - Excellent femoral exposure for stem insertion - Familiar to most Australian surgeons - Good acetabular visualization (anterior and superior) - No posterior soft tissue disruption **Disadvantages:** - Splits abductor mechanism (risk of weakness) - Superior gluteal nerve at risk with proximal extension - Limited posterior acetabular wall access - Higher abductor weakness compared to anterior approach The **Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR)** reports that direct lateral approach accounts for approximately **40% of primary THA** in Australia, making it the most common approach nationally. ### Key Anatomy **Muscular layers (superficial to deep):** 1. **Tensor fascia lata (TFL)** - anterior muscle of iliotibial band 2. **Gluteus medius (GM)** - main hip abductor 3. **Gluteus minimus** - deep hip abductor 4. **Hip joint capsule** **Neurovascular structures:** - **Superior gluteal nerve (L4-S1)**: Exits pelvis above piriformis, **5cm proximal to greater trochanter** - **Superior gluteal artery**: Accompanies nerve, bleeding if violated - **Inferior gluteal nerve and vessels**: Posteriorly (safe) - **Femoral neurovascular bundle**: Anteriorly (safe) The **superior gluteal nerve** exits the greater sciatic notch approximately **5cm proximal to the tip of the greater trochanter**. It innervates gluteus medius, gluteus minimus, and TFL. Injury causes **irreversible Trendelenburg gait**. Measure this distance intraoperatively and avoid dissection beyond 4cm proximal to GT. **Trochanteric anatomy:** - **Greater trochanter**: Insertion of gluteus medius (superior facet), gluteus minimus (anterior facet) - **Vastus ridge**: Lateral femur - origin of vastus lateralis - **Piriformis fossa**: Medial GT - landmark for femoral canal {/* SECTION 5: ANATOMY AND BIOMECHANICS */} **Neuromuscular anatomy:** The key to understanding the Hardinge approach is appreciating that **there is no true internervous plane**. Both muscles in the interval (TFL and gluteus medius) are supplied by the superior gluteal nerve, making this a muscle-splitting rather than muscle-separating approach. **Superior gluteal nerve course:** - Exits pelvis through greater sciatic notch above piriformis - Passes between gluteus medius and minimus - **Enters muscles approximately 5cm proximal to GT tip** - Supplies: Gluteus medius, gluteus minimus, tensor fasciae latae - Injury causes permanent abductor paralysis **Biomechanical considerations:** **Abductor mechanism:** - Gluteus medius is the primary hip abductor - Moment arm: Distance from hip center to GT - Required for pelvic stability during single-leg stance - Splitting the muscle temporarily weakens abduction - Meticulous repair essential for functional recovery **Muscle fiber architecture:** - GM: Fan-shaped, multiple pennation angles - Anterior fibers: Internal rotation, flexion - Middle fibers: Pure abduction - Posterior fibers: External rotation, extension - Splitting anterior portion preserves majority of function {/* SECTION 5b: INTERNERVOUS PLANE */} ### No True Internervous Plane The Direct Lateral (Hardinge) approach involves splitting muscles that are supplied by the same nerve. - **Interval**: Between Tensor Fascia Lata (TFL) and Gluteus Medius. - **Nerve Supply**: **Superior Gluteal Nerve** supplies BOTH muscles. - **Technique**: The approach involves splitting the TFL and the anterior one-third of the Gluteus Medius. - **Safety**: To minimize denervation, the split in the Gluteus Medius should not extend more than **5 cm proximal** to the greater trochanter (nerve entry point). This is distinguishing feature from the Anterior (Smith-Petersen) which has a TRUE internervous plane. {/* SECTION 6: CLASSIFICATION SYSTEMS */} ### Direct Lateral Approach Variants **Original McFarland-Osborne (1954):** - Full transgluteal split - Higher denervation risk - Largely abandoned **Hardinge Modification (1982):** - Splits anterior half of GM at musculotendinous junction - Current standard - Minimizes denervation **Dall Modification:** - Detaches anterior GM insertion completely - Easier repair via bone tunnels - Some prefer for revision cases The Hardinge modification is the standard technique described here. ### Trendelenburg Classification | Grade | Description | Clinical Significance | |-------|-------------|----------------------| | 0 | No pelvic drop | Normal abductor function | | 1 | Mild drop (under 2cm) | Minor weakness, often compensated | | 2 | Moderate drop (2-4cm) | Significant weakness, visible limp | | 3 | Severe drop (over 4cm) | Severe weakness, assistive device needed | Grading helps monitor recovery and identifies patients needing intervention. ### Heterotopic Ossification Classification | Grade | Description | Clinical Impact | |-------|-------------|-----------------| | I | Islands of bone in soft tissue | None | | II | Spurs from pelvis/femur (gap over 1cm) | Minimal | | III | Spurs with gap under 1cm | May limit motion | | IV | Apparent ankylosis | Severe limitation | Direct lateral approach has 10-30% radiographic HO but only 5% symptomatic. {/* SECTION 7: CLINICAL ASSESSMENT */} **Preoperative Assessment:** **History:** - Nature and duration of hip pathology - Previous surgery (affects approach choice) - Functional status and expectations - Medical comorbidities affecting surgery **Physical Examination:** - Gait assessment (baseline Trendelenburg) - Range of motion (flexion, rotation, abduction) - Leg length assessment - Neurovascular status documentation - Abductor strength (baseline for comparison) **Specific assessment for Hardinge approach:** - **Abductor strength testing**: Pre-existing weakness may worsen - **Obesity assessment**: BMI over 35 increases technical difficulty - **Skin condition**: Lateral incision site evaluation - **Hip ROM**: Extension needed for femoral preparation **Document baseline abductor function** before surgery. If patient has pre-existing Trendelenburg from previous surgery or pathology, this must be noted. Post-operative weakness will be blamed on surgery if not documented preoperatively. {/* SECTION 8: INVESTIGATIONS */} **Imaging:** **Essential:** - **AP pelvis radiograph**: Both hips for comparison, templating - **Lateral hip**: Femoral version, anterior osteophytes - **Cross-table lateral**: If patient cannot flex hip **Templating requirements:** - Acetabular cup size and position - Femoral stem sizing and offset - Leg length correction planning - Identifies challenging anatomy (protrusio, DDH) **Advanced imaging (selective):** - **CT**: Complex anatomy, revision surgery, bone stock assessment - **MRI**: Soft tissue assessment, AVN staging, infection workup - **Bone scan**: Infection or loosening workup **Laboratory:** - FBC, UEC, coagulation studies - Group and hold (cross-match if revision) - CRP/ESR if infection concern - HbA1c for diabetics {/* SECTION 9: MANAGEMENT ALGORITHM */} ### Approach Selection Algorithm **Step 1: Is patient suitable for ANY THA?** - Failed conservative management - Adequate bone stock for implants - Medical fitness for surgery **Step 2: Hardinge approach considerations** **Ideal candidates:** - Primary THA with standard anatomy - Femoral neck fracture (hemiarthroplasty) - Low dislocation risk priority - Surgeon comfortable with approach **Consider alternatives if:** - Previous lateral surgery with abductor damage - Need for extensive posterior acetabular access - Severe DDH requiring proximal exposure - Patient preference after informed consent Surgeon experience is the most important factor in approach selection. ### Key Intraoperative Decision Points **Exposure decisions:** - GM split extent (stay under 5cm from GT) - Capsulotomy type (T-shaped vs excision) - Need for additional exposure **Troubleshooting:** - Poor exposure → Extend distally, NOT proximally - Bleeding from proximal → Pack, do NOT chase blindly - Inadequate femoral exposure → Leg position adjustments **Component decisions:** - Cup position: 40-45° inclination, 15-20° anteversion - Stem version: 10-15° anteversion - Offset restoration for abductor tension Avoid proximal extension even if exposure seems limited. ### Rehabilitation Protocol **Day 0-1:** - Weight bearing as tolerated with frame - Hip precautions (controversial) - Pain management, DVT prophylaxis **Weeks 1-6:** - Progress mobility aids - Abductor strengthening exercises - Monitor for Trendelenburg **Weeks 6-12:** - Continue strengthening - Return to driving (6-8 weeks) - Discharge from physio when independent **Beyond 3 months:** - Full activities as tolerated - Annual follow-up initially - Report new symptoms immediately Abductor recovery takes 3-6 months - reassure patients. {/* SECTION 5: POSITIONING AND SETUP */} **Lateral decubitus** position on radiolucent table with affected hip up. - **Pelvis perpendicular** to floor (check with C-arm AP view) - **Anterior supports**: Pubis and sacrum - **Posterior support**: Against sacrum - **Perineal post**: If using traction table (not mandatory) - **Down leg**: Pillow between knees, pad fibular head (peroneal nerve) - **Up leg**: Free to move through range of motion - **Axilla**: Protect brachial plexus with arm support - **All bony prominences**: Gel pads - **Limb free-draped** from iliac crest to mid-calf - **Hip can be extended, flexed, adducted, rotated** freely - **C-arm access**: Confirm adequate AP and lateral imaging - **Incision landmarks visible**: ASIS, GT, femoral shaft - **Retractors**: Hohmann, Charnley, bent Hohmann - **Oscillating saw**: For femoral neck cut - **Implants**: Confirm size range available - **Trial components**: Full range of head sizes, neck lengths The **pelvis must be perpendicular** to the floor. Pelvic tilt or rotation causes **acetabular malposition** (anteversion/retroversion errors). Use C-arm to confirm true AP pelvis before starting. The obturator foramen should be symmetric and the coccyx should align with pubic symphysis. {/* SECTION 6: STEP-BY-STEP TECHNIQUE */} ### Skin Incision and Superficial Dissection **Landmarks:** - Greater trochanter (GT) - palpable landmark - Incision centered over GT - Direction: Straight lateral, parallel to femoral shaft **Incision:** - **Length**: 10-15cm (8cm minimum for primary THA) - **Proximal extent**: 5cm proximal to tip of GT - **Distal extent**: 5cm distal to GT along femoral shaft - **Depth**: Through skin and subcutaneous fat to fascia lata **Superficial dissection:** - Identify **fascia lata** (iliotibial band) - Palpate **greater trochanter** deep to fascia - **Hemostasis** of subcutaneous layer before proceeding The incision must be **centered over the greater trochanter**. Too anterior risks the femoral neurovascular bundle, too posterior makes anterior capsule difficult to reach. Palpate the GT carefully before marking incision. ### Fascia Lata and Tensor Fascia Lata Split **Fascia lata incision:** - Incise fascia in line with skin incision - Full length of skin incision (proximal to distal) - Expose **tensor fascia lata (TFL)** anteriorly and **gluteus maximus** posteriorly **TFL split:** - Split the **anterior third** of TFL fibers - Direction: In line with muscle fibers (longitudinal) - Use **blunt dissection** to develop plane - Extend proximally to gluteus medius, distally to vastus lateralis **Identify gluteus medius:** - **GM visible deep to TFL** split - Muscle fibers run obliquely (superior-lateral to inferior-medial) - **Musculotendinous junction** visible as transition from red muscle to white tendon Splitting the **anterior third of TFL** positions you over the **anterior half of gluteus medius**, which is the safe zone for the Hardinge approach. This minimizes denervation of GM since the superior gluteal nerve enters posteriorly. ### Gluteus Medius Split at Musculotendinous Junction **Key concept:** - The gluteus medius is split at its **musculotendinous junction** - Split **anterior half** of GM only (posterior half left intact) - This minimizes denervation since SGA nerve enters muscle posteriorly **Technique:** - Identify **anterior border** of GM insertion on GT - Using **diathermy**, incise GM tendon **in line with anterior third** - Lift tendon sleeve anteriorly **off greater trochanter** - Continue split proximally into muscle belly for 4-5cm - **Stop at 4cm proximal to GT** to protect superior gluteal nerve **Gluteus minimus:** - GM split exposes **gluteus minimus** deep layer - Minimus is split in line with medius - Both layers retracted anteriorly as a sleeve **Trochanteric bursectomy:** - Excise **trochanteric bursa** (often inflamed) - Improves visualization - Reduces post-op inflammation **Never extend the gluteus medius split more than 5cm proximal to the greater trochanter**. The superior gluteal nerve exits the pelvis at this level. Measuring with a ruler intraoperatively is recommended. Violation causes **permanent abductor paralysis** and Trendelenburg gait. ### Vastus Lateralis Reflection **Identify vastus lateralis:** - Distal extension of incision exposes **vastus lateralis** origin - VL originates from **vastus ridge** (lateral linea aspera) - Muscle fibers run distally along lateral femur **Reflection technique:** - Using **diathermy**, elevate VL origin from vastus ridge - Direction: **Anteriorly** (towards rectus femoris) - Length: Elevate 5-8cm distally from GT - Preserve **lateral femoral circumflex vessels** if possible (deep to VL) **Exposure achieved:** - Anterior reflection of VL exposes **proximal lateral femur** - Greater trochanter now fully visible - Anterior capsule accessible This step completes the muscular dissection and exposes the hip joint capsule anteriorly and laterally. ### Hip Capsule Incision **Capsule exposure:** - Retract GM-minimus sleeve anteriorly with **Charnley retractor** - Retract VL anteriorly - Hip capsule now visible from **anterior to lateral** aspect **Capsulotomy technique:** - **T-shaped capsulotomy** is standard - Longitudinal limb: Along **femoral neck** anteriorly - Transverse limb: Along **acetabular rim** superiorly - Alternative: **H-shaped** or **excise anterior capsule** **Tag capsule:** - Place stay sutures in capsular flaps - Facilitates later repair - Capsular repair reduces dislocation risk **Expose femoral neck:** - Place **bent Hohmann retractor** around femoral neck anteriorly - Second Hohmann posteriorly (behind neck) - Neck now circumferentially exposed for osteotomy There is debate about **capsular excision vs preservation**. Capsular repair may reduce dislocation risk but increases stiffness. Most surgeons using Hardinge approach excise anterior capsule for better exposure but preserve posterior capsule for stability. ### Femoral Neck Osteotomy **Confirm level:** - Use **preoperative templating** to determine osteotomy level - Typically **1cm proximal to lesser trochanter** - Angle: 45 degrees to femoral shaft (varies by implant) **Technique:** - Protect soft tissues with retractors - Use **oscillating saw** - Cut perpendicular to neck axis - **Remove femoral head** with corkscrew extractor **Assess acetabulum:** - Remove loose osteophytes - Assess **acetabular version and inclination** - Place retractors around acetabulum (anterior, posterior, inferior) Femoral neck removal gives access to both femoral canal and acetabulum for implant preparation. ### Closure and Abductor Repair **Critical step - Abductor repair:** - This is the **most important closure step** in Hardinge approach - Poor repair causes Trendelenburg gait and patient dissatisfaction **Gluteus medius repair technique:** - **Option 1 (Bone tunnels)**: Drill tunnels through GT, pass non-absorbable suture (e.g., No. 2 Ethibond) - **Option 2 (Suture to vastus ridge)**: Repair GM to vastus lateralis origin with interrupted sutures - **Tension**: Repair with hip in **neutral position** (not abducted - causes tension) - **Number**: At least 4-6 interrupted sutures **Layer closure:** 1. **Gluteus medius + minimus**: Repair back to GT or vastus ridge (non-absorbable) 2. **TFL**: Re-approximate split with absorbable suture 3. **Fascia lata**: Close with absorbable suture (e.g., 0 Vicryl) 4. **Subcutaneous**: 2-0 Vicryl 5. **Skin**: Staples or subcuticular (surgeon preference) **Drain:** - Optional (surgeon preference) - If used: Remove at 24 hours **Meticulous gluteus medius repair** is the difference between excellent and poor outcomes with Hardinge approach. Use non-absorbable suture, tension appropriately (not too tight), and ensure secure fixation. Abductor failure rates up to 20% if repair inadequate. {/* SECTION 11: STRUCTURES AT RISK */} The **Superior Gluteal Nerve** is the primary structure at risk. It exits the greater sciatic notch and runs between gluteus medius and minimus, entering the muscles approximately **4-5 cm proximal to the greater trochanter**. Injury results in abductor paralysis and Trendelenburg gait. **Safe Zone**: Dissection must remain distal to this 5cm danger zone. {/* SECTION 14: COMPLICATIONS */} ### Complications Specific to Hardinge Approach **Abductor dysfunction:** - Incidence: 5-20% (varies by series) - Causes: Superior gluteal nerve injury, poor GM repair, excessive splitting - Prevention: Limit proximal dissection, meticulous repair - Treatment: Physiotherapy, if persistent consider revision repair or GT advancement **Heterotopic ossification:** - Incidence: 10-30% (radiographic), 5% symptomatic - Risk factors: Male, DISH, previous HO, delay to surgery - Prevention: Indomethacin 25mg TDS for 6 weeks or single-dose radiation - Treatment: Excision if symptomatic after maturation (12 months) **Dislocation:** - Incidence: 2-3% (lower than posterior approach) - Direction: Usually posterior (if occurs) - Prevention: Restore offset, avoid combined flexion-adduction-internal rotation - Treatment: Closed reduction, if recurrent consider revision Even with perfect technique, patients typically have **temporary abductor weakness** for 3-6 months post-operatively. Trendelenburg gait is common early. Reassure patients this improves with physiotherapy. Persistent weakness beyond 6 months warrants investigation (EMG to assess nerve, MRI to assess repair integrity). {/* SECTION 15: POSTOPERATIVE CARE */} **Immediate Postoperative Period (Day 0-2):** **Pain Management:** - Multimodal analgesia (paracetamol + NSAID + opioid PRN) - Regional block consideration (fascia iliaca or femoral) - PCA for first 24-48 hours if needed - Transition to oral by day 1-2 **Mobilization:** - **Weight bearing as tolerated** from day 0 - Walking frame initially, progress to crutches/stick - Physiotherapy assessment for safe mobility - Stairs before discharge **DVT Prophylaxis:** - Mechanical: TED stockings, calf pumps - Chemical: Rivaroxaban 10mg daily for 5 weeks OR enoxaparin OR aspirin - Early mobilization most important **Hip Precautions:** - **Controversial for direct lateral approach** - Some surgeons: No precautions needed - Conservative: Avoid extremes of motion for 6 weeks - Most important: Avoid combined flexion-adduction-IR **Wound Care:** - Waterproof dressing until healed (10-14 days) - Remove staples/sutures at 10-14 days - Monitor for wound complications - Lateral wound position: Less contamination risk than posterior **Discharge:** - Typically day 1-3 for primary THA - Criteria: Safe mobility, wound satisfactory, pain controlled - Arrange outpatient physiotherapy - Emergency contact information provided **Rehabilitation:** **Weeks 1-6:** - Continue walking aids (frame → crutches → stick) - **Abductor strengthening** - critical for this approach - Range of motion exercises (within precautions) - Monitor for Trendelenburg development **Weeks 6-12:** - Wean walking aids - Progress strengthening program - Return to driving (typically 6-8 weeks) - Swimming, stationary cycling permitted **Beyond 3 months:** - Return to full activities as comfort allows - Low-impact sports acceptable - Annual review initially, then as needed - Lifelong follow-up recommended **Abductor weakness is EXPECTED** after Hardinge approach. Most patients have some Trendelenburg for 3-6 months. Reassure patients this improves. Persistent weakness beyond 6 months requires investigation (MRI for repair, EMG for nerve). {/* SECTION 16: OUTCOMES AND PROGNOSIS */} **Functional Outcomes:** **Short-term (under 2 years):** - Pain relief: Over 95% significant improvement - Function: Harris Hip Score typically improves from 45 to over 85 - Patient satisfaction: Over 90% satisfied or very satisfied - Return to activities: 3-6 months for most **Long-term (over 10 years):** - **Implant survival**: Over 95% at 10 years (similar to other approaches) - **Revision rate**: Approximately 1% per year - **Dislocation rate**: 2-3% (lower than posterior approach) - **Functional maintenance**: Most maintain excellent function **Approach-Specific Outcomes:** **Abductor function:** - Temporary weakness (under 6 months): 50-70% of patients - Persistent weakness (over 6 months): 5-20% - Permanent Trendelenburg: 3-5% - Directly related to repair quality and nerve protection **Dislocation comparison:** | Approach | Dislocation Rate | |----------|-----------------| | Direct Lateral | 2-3% | | Posterior | 5-7% | | Anterior | 1-2% | **Heterotopic ossification:** - Any grade: 10-30% - Clinically significant: 5% - Higher than posterior approach - Prophylaxis reduces significantly **Prognostic Factors:** **Good prognosis:** - Primary THA for osteoarthritis - Experienced surgeon - Meticulous GM repair technique - Good preoperative abductor function - Compliant with rehabilitation **Poorer prognosis:** - Revision surgery - Pre-existing abductor weakness - Obesity (BMI over 35) - Poor repair quality - Superior gluteal nerve injury **Registry Data:** Per AOANJRR, the direct lateral approach has revision rates equivalent to other approaches at 10 years. Surgeon volume and experience are more important predictors of outcome than approach selection. {/* SECTION 17: EVIDENCE BASE */} {/* SECTION 9: VIVA SCENARIOS */} {/* SECTION 10: MCQ PRACTICE POINTS */} **Q: What is the internervous plane in the Hardinge direct lateral approach to the hip?** A: **There is NO true internervous plane**. Both tensor fascia lata and gluteus medius are supplied by the superior gluteal nerve. The approach splits both muscles (TFL anteriorly, GM at musculotendinous junction) to minimize denervation. **Q: At what distance from the greater trochanter does the superior gluteal nerve exit the pelvis?** A: Approximately **5cm proximal to the tip of the greater trochanter**. Dissection beyond this point risks permanent abductor paralysis. Limit proximal extension to 4cm from GT to maintain safe zone. **Q: Where is the gluteus medius split in the Hardinge approach?** A: The **anterior half of gluteus medius** is split at the **musculotendinous junction**. This is approximately anterior third of the muscle. Splitting at the junction minimizes denervation compared to splitting through muscle belly. **Q: What is the dislocation rate after primary THA via Hardinge approach compared to posterior approach?** A: Hardinge (direct lateral) has **lower dislocation rate** (approximately 3%) compared to posterior approach (5-7%). However, Hardinge has higher risk of abductor dysfunction. **Q: What is the most critical step in closing a Hardinge approach?** A: **Meticulous repair of the gluteus medius** back to the greater trochanter using non-absorbable suture (e.g., No. 2 Ethibond). Poor repair causes Trendelenburg gait and abductor dysfunction in up to 20% of patients. {/* SECTION 11: AUSTRALIAN CONTEXT */} **AOANJRR Data:** - Direct lateral approach is the **most common THA approach** in Australia (40% market share) - Posterior approach second (35%) - Anterior approach growing (20%) - Regional variation: More lateral in Victoria/SA, more posterior in NSW/QLD **Training implications:** - Most Australian orthopaedic trainees learn Hardinge as **primary THA approach** - Important for Orthopaedic exam - examiners expect detailed knowledge - Familiarity with approach selection based on patient factors **Medico-legal considerations:** - Abductor dysfunction is a **recognized complication** - must be in consent - Superior gluteal nerve injury is **preventable** - staying under 5cm from GT is standard of care - Documentation of repair technique important if post-op abductor weakness For Orthopaedic exam, you must be able to describe the Hardinge approach in detail including: positioning, skin incision, muscle intervals (TFL split, GM split at musculotendinous junction), structures at risk (superior gluteal nerve 5cm from GT), and closure technique (GM repair with non-absorbable suture). Know the AOANJRR data showing it's the most common approach in Australia. {/* SECTION 12: EXAM CHEAT SHEET */}

Hip Direct Lateral Approach (Hardinge)

Hip Direct Lateral Approach (Hardinge)