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 */} **Common exam trap:** Candidates say this is an internervous plane. It is NOT. Both TFL and gluteus medius are supplied by the **superior gluteal nerve**. The interval is between muscles with the same nerve supply, making proximal extension risky. **Superior gluteal nerve** exits the greater sciatic notch approximately **5cm proximal to the tip of the greater trochanter**. Dissection beyond this risks denervation of gluteus medius and minimus, causing Trendelenburg gait. Stay distal to this safe zone. Original approach detached TFL from GT. **Modern modification**: Split TFL fibers longitudinally and reflect gluteus medius posteriorly without detachment. Preserves abductor mechanism and improves recovery. The key to good functional outcomes is **preserving the abductor mechanism**. Avoid excessive retraction of gluteus medius, repair any inadvertent tears, and protect superior gluteal nerve. Abductor deficiency causes Trendelenburg limp and poor patient satisfaction. {/* SECTION 2.5: QUICK DECISION GUIDE */} {/* SECTION 3: MNEMONICS */} {/* SECTION 4: OVERVIEW */} The **Watson-Jones anterolateral approach** was described by Sir Reginald Watson-Jones in 1936 for hip arthrodesis and fracture management. It utilizes the interval between tensor fasciae latae (anterior) and gluteus medius (posterolateral), though both muscles are supplied by the superior gluteal nerve, making it **not a true internervous plane**. **Historical evolution:** - 1936: Original description by Watson-Jones for arthrodesis - 1950s-1970s: Popular for femoral neck fractures and hip arthroplasty - 1980s-1990s: Fell out of favor due to abductor complications - 2000s: Revival with muscle-sparing modifications for THA **Modern modifications:** The original approach detached TFL from the greater trochanter. **Modern muscle-sparing technique:** - Split TFL longitudinally along fiber direction - Reflect gluteus medius posteriorly without detachment - Preserve all muscle attachments to bone - Minimize retraction force on abductors This has reduced abductor complications and improved functional outcomes. **Current applications:** 1. **Primary total hip arthroplasty** - common approach in some regions 2. **Femoral neck fracture management** - hemiarthroplasty or fixation 3. **Hip arthroscopy** - same anatomical corridor for conversion to open 4. **Revision THA** - acetabular component exposure The anterolateral approach is often **confused with the anterior approach** (Smith-Petersen). Key differences: Watson-Jones is between TFL and glut med (same nerve), while Smith-Petersen is between TFL and sartorius (different nerves). Knowing this distinction is critical for exams. {/* SECTION 5: ANATOMY AND BIOMECHANICS */} The Watson-Jones anterolateral approach requires detailed understanding of the musculature, neurovascular structures, and biomechanics of the hip region to achieve safe exposure while preserving function. **Biomechanical Considerations:** The hip abductor mechanism is critical for normal gait. Gluteus medius and minimus act to stabilize the pelvis during single-leg stance, preventing pelvic drop (Trendelenburg sign). Any disruption to these muscles or their nerve supply compromises this essential function. **Key biomechanical principles:** - **Abductor moment arm**: Distance from hip center to abductor insertion on GT determines mechanical advantage - **Offset restoration**: Lateral femoral offset affects abductor tension and function - **Soft tissue tension**: Must balance stability against impingement risk - **Lever arm of body weight**: Acts through center of mass, countered by abductors The approach exploits the interval between TFL and gluteus medius, but both muscles share the same nerve supply (superior gluteal), making this NOT a true internervous plane. This anatomical fact has critical surgical implications. {/* SECTION 6: DETAILED ANATOMY */} **Surface anatomy:** - **Greater trochanter (GT)** - primary landmark, lateral prominence of proximal femur - **ASIS** - anterior reference point - **Iliac crest** - posterior boundary - **Femoral shaft** - palpable distally **Muscular interval:** **Deep structures:** - **Hip joint capsule** - accessed between muscles after splitting TFL and reflecting GM - **Reflected head of rectus femoris** - originates from superior acetabular rim - **Iliofemoral ligament** - strongest hip ligament, anterior capsule - **Ascending branch of lateral circumflex femoral artery** - runs deep, requires ligation **Bony landmarks:** - **Greater trochanter** - lateral prominence, insertion point for abductors - **Vastus ridge** - lateral femur, marks anterior border of vastus lateralis - **Femoral neck** - accessed after capsulotomy {/* SECTION 7: INTERNERVOUS PLANE */} ### No True Internervous Plane The Watson-Jones approach utilizes the interval between **Tensor Fasciae Latae (TFL)** and **Gluteus Medius**. However, this is **NOT a true internervous plane** because both muscles are supplied by the **Superior Gluteal Nerve**. **Critical anatomy - Superior gluteal nerve:** The **superior gluteal nerve** (L4-L5-S1) exits the pelvis through the **greater sciatic notch** superior to the piriformis muscle. It divides into superior and inferior branches: - **Superior branch**: To gluteus medius and minimus (main trunk) - **Inferior branch**: To tensor fasciae latae The nerve crosses the interval approximately **5cm proximal to the tip of the greater trochanter**. Dissection beyond this level risks denervation of the abductors. **Clinical consequence of injury:** Trendelenburg gait due to gluteus medius/minimus weakness. {/* SECTION 7: CLASSIFICATION SYSTEMS */} ### Watson-Jones Approach Modifications **Original Watson-Jones (1936):** - TFL detached from greater trochanter - Anterior gluteus medius detached - Maximum exposure but high abductor risk **Muscle-Sparing Modification (Current Standard):** - TFL split longitudinally (no detachment) - GM reflected posteriorly (no detachment) - Reduced abductor complications **Mini-Incision Modification:** - Smaller skin incision (8-10cm) - Same anatomical interval - Used for minimally invasive THA The muscle-sparing modification is now the standard technique. ### Superior Gluteal Nerve Injury Grading **Sunderland Classification for nerve injury:** | Grade | Pathology | Prognosis | |-------|-----------|-----------| | I | Neurapraxia (conduction block) | Complete recovery in weeks | | II | Axonotmesis (axon damage) | Recovery over months | | III | Partial endoneurial damage | Variable recovery | | IV | Perineurial damage | Poor without surgery | | V | Complete transection | No recovery without repair | Most Watson-Jones nerve injuries are Grade I-II with good prognosis. ### Brooker Classification of HO | Grade | Description | Clinical Impact | |-------|-------------|-----------------| | I | Islands of bone in soft tissue | Minimal | | II | Bone spurs from pelvis or femur with gap over 1cm | Minimal | | III | Bone spurs with gap under 1cm | May limit motion | | IV | Apparent bony ankylosis | Severe ROM limitation | Anterolateral approach has higher HO risk than posterior. Prophylaxis with indomethacin or radiation indicated for high-risk patients. {/* SECTION 8: INDICATIONS AND CONTRAINDICATIONS */} **Primary indications:** **Ideal candidates for Watson-Jones THA:** **Patient factors:** - Primary THA with normal anatomy - Young to middle-aged patients - Good abductor muscle quality - No significant obesity (BMI under 35 preferred) **Advantages:** - Excellent acetabular exposure - Good femoral exposure for primary THA - Can be performed supine or lateral (surgeon preference) - Lower dislocation rate than posterior (theoretically) - Preserves posterior capsule and short external rotators **Disadvantages compared to other approaches:** - Risk to superior gluteal nerve if dissect too proximal - Potential abductor damage with poor technique - More muscle trauma than true anterior approach - Heterotopic ossification slightly higher than posterior **Technical pearls:** - Use muscle-sparing modification (split TFL, don't detach) - Limit proximal dissection to 5cm above GT - Gentle retraction of gluteus medius to avoid damage - Repair any inadvertent tears in abductors before closure This remains a popular choice for surgeons trained in this approach. **Excellent approach for fracture management:** **Why choose Watson-Jones for fractures:** - **Quick access** to hip joint for hemiarthroplasty or THA - **Supine positioning** familiar to trauma surgeons - **Less bleeding** than posterior approach in many cases - **Good visualization** of femoral neck for screw placement (young patients) **Fracture types:** - Displaced femoral neck fractures → hemiarthroplasty or THA - Non-displaced FN fractures in young → can expose for screw fixation - Intertrochanteric fractures → can slide hip screw via this approach (less common) **Advantages in trauma setting:** - Familiar anatomy if surgeon routinely uses this for elective THA - Can perform bilateral procedures if needed (bilateral FN fractures) - Supine positioning easier for anesthesia in elderly/unwell patients **Caution:** - In emergency setting, avoid hasty dissection risking abductor damage - Carefully identify and protect superior gluteal nerve - Ensure adequate hemostasis (ascending LCFA branch) This is a safe and effective approach for femoral neck fracture management. **Role in revision arthroplasty:** **Good for:** - **Acetabular revisions** - excellent cup exposure - **Liner exchange** - can easily access acetabulum - **Modular head/neck exchange** - adequate femoral exposure - **Conversion from hip arthroscopy** if needed **Challenging for:** - **Complex femoral revisions** - limited distal femur exposure - **Extended trochanteric osteotomy** - posterior approach preferred - **Severe heterotopic ossification** - may need different approach **Technical considerations:** - Previous surgery may have scarring in interval - Abductors may be damaged from prior surgery - Superior gluteal nerve may be at higher risk due to distorted anatomy - Consider alternative approach if significant abductor deficiency The choice between anterolateral vs posterior for revision depends on what component needs revision and prior surgical approach. **Additional clinical scenarios:** **Hip arthroscopy conversion:** - Anterolateral portal uses same anatomical corridor - Familiar anatomy if scoped first - Can convert to open if unable to complete arthroscopically - Be aware of iatrogenic labral or chondral damage from scope **Hip arthrodesis:** - Historical indication (Watson-Jones' original use) - Rarely performed in modern practice - Requires wide exposure for joint preparation and fixation **Open reduction of hip dislocation:** - Can access hip joint for fragment removal - Allows assessment of femoral head and acetabulum - Less common now with improved arthroscopic techniques **Synovectomy/tumor:** - Joint access for synovectomy in inflammatory arthritis - Biopsy of hip joint lesions - Limited use compared to arthroscopic techniques The versatility of this approach makes it useful across various clinical scenarios. **Contraindications:** **Absolute:** - Active infection (relative - can still use if necessary) - Patient request for specific approach (after discussion) **Relative:** - Severe obesity (BMI over 40) - difficult exposure, higher complication rate - Prior anterolateral surgery with known abductor damage - Known superior gluteal nerve palsy - Severe osteoporosis (fracture risk with retraction) {/* SECTION 9: CLINICAL ASSESSMENT */} Thorough preoperative assessment is essential for approach selection and surgical planning via the Watson-Jones anterolateral approach. **History:** - **Nature of hip pathology**: Primary OA, inflammatory arthritis, AVN, DDH, fracture - **Previous hip surgery**: May have scarring in surgical corridor - **Abductor function**: Pre-existing weakness or limp - **Medical comorbidities**: Obesity, diabetes, immunosuppression - **Medication review**: Anticoagulation, immunomodulators **Physical Examination:** **Key examination findings:** - **Gait assessment**: Pre-existing limp, Trendelenburg (abductor weakness) - **Range of motion**: Flexion, rotation, abduction limitations - **Leg length**: Clinical measurement, apparent vs true discrepancy - **Neurovascular status**: Baseline nerve function documentation - **Abductor strength**: Manual muscle testing - baseline for postoperative comparison - **Trendelenburg test**: Assess pre-existing abductor deficiency **Specific considerations for Watson-Jones approach:** - Patients with pre-existing abductor weakness may be at higher risk of postoperative Trendelenburg - Obesity (BMI over 35) increases technical difficulty - Prior anterolateral surgery creates scarring in interval - Document baseline neurological status for medicolegal protection {/* SECTION 10: INVESTIGATIONS */} **Imaging:** **Plain Radiographs (Essential):** - **AP pelvis**: Bilateral comparison, acetabular morphology, leg length - **Lateral hip**: Femoral head-neck offset, anterior osteophytes - **Cross-table lateral**: Better femoral assessment when not weight-bearing **Radiographic templating:** - Acetabular cup size and position planning - Femoral stem sizing and offset - Leg length assessment and correction planning - Identifies need for bone graft or augments **Advanced Imaging (Selective):** **CT Scan:** - Complex acetabular anatomy (dysplasia, protrusio) - Previous hardware assessment - 3D reconstruction for navigation planning - Bone stock assessment for revision **MRI:** - AVN staging (if suspected) - Soft tissue assessment (abductor integrity) - Infection workup (fluid collections, edema) - Labral pathology (if arthroscopic conversion planned) **Diagnostic hip injection:** - Differentiates hip vs spine pathology - Lidocaine + steroid under ultrasound or fluoroscopy - Pain relief confirms intra-articular source **Laboratory Studies:** - FBC, UEC, coagulation studies - CRP, ESR if infection concern - HbA1c for diabetics - Nutritional markers (albumin, vitamin D) if malnourished {/* SECTION 11: POSITIONING AND SETUP */} **Positioning options:** The Watson-Jones approach can be performed **supine OR lateral decubitus** depending on surgeon preference and familiarity. ### Supine Positioning (Popular Choice) **Setup:** - Standard operating table - Patient supine with bump under ipsilateral hip/buttock - Allows 20-30 degrees pelvic tilt for femoral exposure - Arms on arm boards, contralateral leg in slight abduction **Advantages:** - **Easier for anesthesia** - better respiratory mechanics - **Bilateral procedures possible** - both hips can be done simultaneously - **Familiar to surgical team** - standard positioning - **Leg length assessment** easier during trial reduction **Technique modifications:** - Hip extension achieved by dropping leg off side of table - May use specialized leg positioner/femoral elevator - Bump under pelvis helps with acetabular exposure **Imaging:** - C-arm from contralateral side for AP views - Lateral views may be limited (cross-table lateral possible) This is the preferred position for many surgeons, particularly in trauma setting. ### Lateral Decubitus Position **Setup:** - Patient in lateral position on beanbag or pegboard - Pelvic supports (anterior ASIS, posterior sacrum) - Pelvis perpendicular to floor (check with spirit level) - Lower leg flexed, upper leg straight **Advantages:** - **Better acetabular exposure** - gravity assists - **Familiar to posterior approach surgeons** - **Easier femoral preparation** in some cases - **Standard for elective THA** in many centers **Technique:** - Same skin incision and approach - Gravity pulls gluteus medius posteriorly - natural retraction - Hip extension by bringing leg into extension on table **Imaging:** - AP pelvis requires C-arm rotation - Lateral views easier to obtain This position is preferred by surgeons who use lateral positioning routinely for all hip approaches. **Preparation steps:** - General or spinal anesthesia - Muscle relaxation for easier retraction - Hypotensive technique (trauma) or controlled hypotension (elective) to reduce bleeding - Supine or lateral per surgeon preference - Ensure adequate padding of pressure points - Arms positioned safely (abduction under 90 degrees) - Pelvis positioning confirmed - Prepare from iliac crest to mid-thigh - Circumferential preparation of thigh - Chlorhexidine or betadine per protocol - Allow adequate drying time (alcohol-based prep) - Extremity draping with stockinette - Include greater trochanter and iliac crest in field - Ensure adequate exposure distally for femoral work - Confirm patient, side, procedure - Antibiotics given (within 60 minutes) - DVT prophylaxis plan confirmed - Equipment available and checked {/* SECTION 12: MANAGEMENT ALGORITHM */} ### Approach Selection Algorithm **Step 1: Is surgery indicated?** - Failed conservative management for OA - Displaced femoral neck fracture - Failed arthroplasty requiring revision **Step 2: Patient factors assessment** - Age, activity level, life expectancy - BMI and body habitus - Pre-existing abductor function - Prior surgery and approach used **Step 3: Surgeon factors** - Training and experience with approach - Available equipment and implants - Volume and outcomes data **Step 4: Watson-Jones specific considerations** - Appropriate for primary THA with standard anatomy - Good for femoral neck fractures - Consider alternative if prior abductor damage or severe obesity The most important factor is surgeon comfort and experience with the chosen approach. ### Key Intraoperative Decision Points **Exposure decisions:** - Muscle-sparing technique (standard) vs traditional (rarely needed) - Extent of capsulotomy (T-shaped vs limited) - Need for proximal extension (stay within 5cm of GT) **Component decisions:** - Acetabular: Press-fit vs cemented, cup size, inclination/anteversion - Femoral: Stem type, size, offset, version - Head/neck: Size selection for stability and leg length **Problem-solving:** - Poor exposure → Extend incision distally, NOT proximally - Intraoperative fracture → Cable/plate fixation, consider stem change - Instability → Re-check component position, consider larger head, constraint The approach rarely needs modification during surgery if properly planned. ### Managing Relative Contraindications **Obesity (BMI over 35):** - Longer incision needed for exposure - Consider alternative approach if BMI over 40 - May need special retractors - Higher wound complication risk **Prior anterolateral surgery:** - Expect scarring in interval - Careful dissection to identify planes - Consider alternative approach if severe scarring **Pre-existing abductor weakness:** - Document baseline carefully - Be extra careful with nerve protection - Consider posterior approach alternative **Severe osteoporosis:** - Careful with retraction (fracture risk) - May need cemented components - Document bone quality intraoperatively Most relative contraindications can be managed with appropriate planning and technique modification. {/* SECTION 13: SURGICAL TECHNIQUE */} ### Incision Planning and Placement **Landmarks:** - **Greater trochanter (GT)** - primary landmark (palpable laterally) - **ASIS** - anterior reference - **Line from ASIS to lateral GT** - incision follows this general direction **Classic Watson-Jones incision:** - Start 5cm distal and posterior to ASIS - Extend distally and posteriorly toward GT - Continue over GT extending distally along femoral shaft - Total length: 10-15cm (can extend as needed) - Centered over interval between TFL and gluteus medius **Muscle-sparing modification incision:** - Shorter incision possible (8-10cm) - Centered over GT - More vertical orientation along femoral shaft The incision should be **centered over the greater trochanter**. Too anterior risks missing the GT and makes femoral exposure difficult. Too posterior encroaches on the gluteus medius insertion and risks damage. ### Superficial Layer Development **Step 1: Incise skin and subcutaneous tissue** - Deepen through subcutaneous fat with cutting diathermy - Achieve hemostasis of skin edge bleeders - Minimal subcutaneous dissection (stay perpendicular) **Step 2: Identify fascia lata and iliotibial band** - Identify glistening white fascia lata - Palpate ITB tension with leg in neutral position - Mark proposed fascial incision with electrocautery **Step 3: Incise fascia lata** - Incise fascia in line with skin incision - Extend over GT and distally along femoral shaft - Proximally: stay within 5cm of GT tip (nerve protection) Do not extend fascial incision more than **5cm proximal to the GT tip**. The superior gluteal nerve crosses the field at this level. Dissection beyond this risks denervation of gluteus medius and minimus. **Step 4: Identify muscular interval** - TFL anteriorly (soft, mobile muscle) - Gluteus medius posteriorly (firmer, taught muscle over GT) - Interval may have fascial condensation - release with scissors Superficial dissection should be efficient and hemostatic before proceeding deep. ### Deep Interval and Muscle Management **Original Watson-Jones technique (less commonly used):** - Detach TFL from GT with periosteal elevator - Reflect TFL anteriorly - Detach anterior 1/3 of gluteus medius from GT - Reflect posteriorly **Modern muscle-sparing technique (PREFERRED):** **Step 1: Split TFL longitudinally** - Identify fiber direction of TFL (oblique, anterior-distal) - Split TFL along fibers with scissors or diathermy - Preserve all bony attachments (NO detachment from GT) - Length of split: 5-8cm **Step 2: Reflect gluteus medius posteriorly** - Place retractor on gluteus medius - Retract posteriorly WITHOUT detaching from GT - Gentle retraction to avoid muscle damage - Identify gluteus minimus deep to medius **Step 3: Manage ascending branch of LCFA** - **Lateral circumflex femoral artery** ascending branch runs deep - Identify between muscles and capsule - Ligate with ties or clips (avoid diathermy near nerve) - This is a consistent bleeder - address early **Step 4: Expose hip capsule** - Retract TFL anteriorly, GM posteriorly - Visualize anterior and lateral hip capsule - Identify reflected head of rectus femoris (superior) - Feel femoral neck anteriorly through capsule The **muscle-sparing modification** (splitting TFL, preserving attachments) has significantly improved outcomes: - Reduced abductor weakness - Faster recovery - Lower Trendelenburg gait incidence - Improved patient satisfaction This is now the standard technique for elective THA via Watson-Jones. The deep dissection should expose adequate capsule without muscle trauma. ### Hip Capsule Management **Capsulotomy pattern options:** **T-shaped capsulotomy (most common for THA):** - Longitudinal limb along femoral neck (anterior) - Transverse limb along acetabular rim - Excise anterior capsule or preserve for repair **H-shaped capsulotomy:** - Two longitudinal limbs - Connected by transverse limb - Creates flaps for repair **Limited capsulotomy (for fracture):** - Minimal capsule opening for hemi head insertion - Preserve capsule for stability **Capsulectomy (some surgeons for THA):** - Excise anterior capsule completely - Theoretically lower dislocation risk - Loss of proprioception (controversial) **Key steps:** 1. Flex hip to relax capsule 2. Incise capsule with knife or scissors 3. Extend capsulotomy as needed for exposure 4. Tag capsular edges with sutures for later repair (if preserving) 5. Expose femoral neck and acetabular rim **Identify important structures:** - **Femoral neck** anteriorly - **Acetabular rim** superiorly - **Transverse acetabular ligament** inferiorly - **Ligamentum teres** (may be degenerated in arthritis) **Capsular repair** after THA via anterolateral approach is controversial: - **Pro-repair**: Improved stability, proprioception, lower dislocation (theoretical) - **Anti-repair**: No proven benefit, adds time, may limit early ROM Most surgeons do NOT routinely repair capsule after anterolateral THA. Posterior approach is different - capsule/short external rotator repair is standard there. The capsulotomy should provide adequate exposure without excessive soft tissue stripping. ### THA Technique via Watson-Jones **Femoral neck osteotomy:** 1. Flex and externally rotate hip 2. Perform in situ neck osteotomy with oscillating saw 3. Cut at predetermined level (preoperative templating) 4. Remove femoral head with corkscrew or bone hook 5. Send head for histology if indicated **Acetabular exposure:** 1. Place anterior and posterior retractors around acetabular rim 2. Excise labrum and remaining capsule 3. Remove osteophytes for visualization 4. Identify transverse acetabular ligament (marks true floor) **Acetabular preparation:** 1. Ream acetabulum to bleeding bone 2. Progressive reamer sizes to planned size 3. Aim for 40-45 degrees inclination, 15-20 degrees anteversion 4. Assess coverage - may need bone graft for defects 5. Implant acetabular component (press-fit or cemented) **Femoral exposure:** 1. Externally rotate and extend hip 2. Bend leg over table edge or use femoral positioner 3. Place bent Hohmann retractor around proximal femur 4. Deliver proximal femur into wound **Femoral preparation:** 1. Open femoral canal with box chisel or awl 2. Progressive broaching or reaming 3. Confirm version (10-15 degrees anteversion typical) 4. Assess stability and offset with trial components **Trial reduction:** 1. Assess stability through ROM 2. Check leg length (comparison to contralateral) 3. Check offset and soft tissue tension 4. Ensure no impingement **Final implantation:** 1. Insert definitive components 2. Reduce hip with appropriate head/neck combination 3. Final stability and ROM check 4. Copious irrigation The technique should achieve stable, well-positioned components without excessive soft tissue trauma. {/* SECTION 10: STRUCTURES AT RISK (Moved) */} **Complications Overview:** - **Superior gluteal nerve injury**: 1-5% (Trendelenburg gait) - **Abductor muscle damage**: 5-15% - **Heterotopic ossification**: 10-20% (higher than posterior) - **Dislocation**: Under 2% (lower than posterior) **Trendelenburg gait** after anterolateral approach THA indicates **abductor dysfunction** (nerve or muscle). Most recover, but prevention (5cm rule) is key. {/* SECTION 9: CLOSURE */} **Wound closure:** - Repair capsule with interrupted absorbable sutures if preserved - Most surgeons do NOT repair capsule after anterolateral THA - For fracture/trauma: consider repair for added stability - **Repair any tears in gluteus medius** - critical for abductor function - TFL split approximates spontaneously (if muscle-sparing technique) - Use absorbable suture (0 or 1 Vicryl) - Ensure no undue tension on repair - Close fascia/ITB with absorbable suture - This is a strong layer - important for wound integrity - May use interrupted or running technique - Close subcutaneous layer (2-0 Vicryl) - Ensure hemostasis before skin closure - Drain controversial - author preference for trauma, not routine for elective - Skin: subcuticular 3-0 Monocryl or staples - Waterproof dressing **Postoperative protocol:** **For elective THA:** - Mobilization: day 0 or day 1 with physiotherapy - **Weight bearing**: Full weight bearing as tolerated (modern implants) - **Hip precautions**: Controversial for anterolateral approach - Some surgeons: no precautions needed - Conservative: avoid extremes of flexion/adduction/internal rotation for 6 weeks - DVT prophylaxis: per protocol (rivaroxaban, enoxaparin, aspirin) - Discharge: typically day 1-2 for routine cases **For femoral neck fracture (hemi/THA):** - Early mobilization critical (elderly patients) - Full weight bearing as tolerated - DVT prophylaxis essential - Discharge to rehab facility often needed **Follow-up:** - 2 weeks: wound check, remove staples if used - 6 weeks: clinical and radiographic assessment - 3 months: function assessment - 1 year: annual review - Ongoing: per surgeon preference and registry requirements {/* SECTION 16: POSTOPERATIVE CARE */} **Immediate Postoperative Period (Day 0-1):** **Analgesia:** - Multimodal pain management (paracetamol + NSAIDs + opioids PRN) - Consider regional blocks (femoral nerve or fascia iliaca block) - PCA (patient-controlled analgesia) for first 24-48 hours **Mobilization:** - **Same day mobilization** is the standard for enhanced recovery - Weight bearing as tolerated (WBAT) with walking frame - Physiotherapy assessment for safe mobilization - Progress from frame to crutches to walking stick **DVT Prophylaxis:** - Mechanical (TED stockings, calf pumps) - Pharmacological per protocol: - Rivaroxaban 10mg daily for 5 weeks (common choice) - Enoxaparin 40mg daily (alternative) - Aspirin 100mg daily (lower-risk patients) - Early mobilization is most important **Hip Precautions:** - **Controversial for anterolateral approach** - Many surgeons: No precautions needed (approach preserves posterior structures) - Conservative approach: Avoid extremes of flexion/adduction/IR for 6 weeks - Individual surgeon preference based on component position and stability **Wound Care:** - Waterproof dressing until wound healed (usually 10-14 days) - Remove staples/sutures at 10-14 days - Monitor for wound complications **Discharge Planning:** - Day 1-2 for routine primary THA - Criteria: Pain controlled, safe mobilization, wound satisfactory - Arrange outpatient physiotherapy - Provide written instructions and emergency contact **Rehabilitation:** **Weeks 1-6:** - Progress weight bearing and mobility - Gait training (aim to wean walking aids) - Range of motion exercises - Abductor strengthening (particularly important for this approach) - Avoid falls and excessive activity **Weeks 6-12:** - Continue strengthening - Increase activity level - Return to driving (typically 4-6 weeks if left hip, 6-8 weeks if right hip) - Progress to normal activities **3-12 Months:** - Return to recreational activities - Most patients achieve maximum improvement by 6-12 months - Annual follow-up for first few years, then per surgeon protocol {/* SECTION 17: OUTCOMES AND PROGNOSIS */} **Functional Outcomes:** **Short-term (under 2 years):** - **Pain relief**: Over 95% report significant pain improvement - **Function**: Harris Hip Score improves from mean 45 preoperatively to over 85 - **Patient satisfaction**: Over 90% satisfied or very satisfied - **Mobility**: Most patients walking without aids by 6 weeks **Long-term (over 10 years):** - **Implant survival**: Over 95% at 10 years (similar to other approaches) - **Revision rate**: Approximately 1% per year - **Dislocation rate**: 1-2% (lower than posterior approach) - **Function maintenance**: Most maintain good function long-term **Approach-Specific Outcomes:** **Trendelenburg gait:** - Temporary (under 6 months): 5-10% - Permanent: 1-3% - Higher than posterior approach (under 2%) - Muscle-sparing technique has reduced this significantly **Heterotopic ossification:** - Any grade: 10-20% - Clinically significant (Brooker 3-4): 3-5% - Higher than posterior approach - Prophylaxis recommended in high-risk patients **Prognostic Factors:** **Good prognosis:** - Primary THA for osteoarthritis - Normal preoperative abductor function - BMI under 35 - Experienced surgeon using muscle-sparing technique - Good bone quality **Poorer prognosis:** - Revision surgery - Pre-existing abductor weakness - Obesity - Inflammatory arthritis - Complex anatomy (dysplasia, previous surgery) **Comparison with Other Approaches:** | Outcome | Anterolateral | Posterior | Direct Anterior | |---------|---------------|-----------|-----------------| | Dislocation | 1-2% | 2-3% | Under 1% | | Trendelenburg | 5% | Under 2% | 2-3% | | HO | 15% | 10% | 8% | | Long-term survival | Equivalent | Equivalent | Equivalent | **Bottom line**: All approaches yield excellent long-term outcomes when performed well by experienced surgeons. Approach selection should be based on surgeon training and comfort. {/* SECTION 18: EVIDENCE BASE */} {/* SECTION 12: VIVA SCENARIOS */} {/* SECTION 13: MCQ PRACTICE */} **Q: Is the Watson-Jones anterolateral approach a true internervous plane?** A: **NO**. This is a common exam mistake. Both tensor fasciae latae and gluteus medius are supplied by the **superior gluteal nerve**, making this an intranervous interval between muscles with the same nerve supply. Smith-Petersen anterior approach (TFL vs sartorius) IS a true internervous plane. **Q: What is the 5cm rule for the superior gluteal nerve in the Watson-Jones approach?** A: The **superior gluteal nerve** exits the greater sciatic notch approximately **5cm proximal to the tip of the greater trochanter**. Dissection or retraction beyond this level risks nerve injury and denervation of gluteus medius/minimus, causing **Trendelenburg gait**. **Q: What is the clinical presentation of superior gluteal nerve injury after hip surgery?** A: **Trendelenburg gait** - the pelvis drops on the contralateral side during single-leg stance on the affected leg. This is due to weakness of the hip abductors (gluteus medius and minimus). Patient has difficulty with stairs and prolonged walking. **Q: What is the muscle-sparing modification of the Watson-Jones approach and why is it preferred?** A: The traditional technique detached TFL and anterior gluteus medius from the greater trochanter. The **muscle-sparing modification** splits TFL longitudinally along fiber direction and reflects gluteus medius posteriorly WITHOUT bony detachment. This reduces abductor complications and Trendelenburg gait incidence from 15-20% to under 5%. **Q: What are the key differences between anterolateral (Watson-Jones) and posterior approaches for THA?** A: **Anterolateral**: NOT internervous (both TFL and GM supplied by superior gluteal nerve), lower dislocation risk (1-2%), higher Trendelenburg risk (5%), supine positioning. **Posterior**: TRUE internervous plane (glut max vs short ER), higher dislocation risk (2-3%), lower Trendelenburg risk (under 2%), lateral positioning, better femoral exposure. {/* SECTION 14: AUSTRALIAN CONTEXT */} **Local practice patterns:** - Watson-Jones approach has variable use across Australia - More popular in some states/regions than others - Surgeon training and experience drives approach choice - AOANJRR tracks approach-specific outcomes **Registry data:** - Dislocation rates: Consistent with international literature - Approach does not significantly affect implant survival at 10+ years - Revision rates similar between approaches for primary THA **Medicolegal considerations:** - **Informed consent** must include approach-specific risks: - Anterolateral: Superior gluteal nerve injury, Trendelenburg gait (5%) - Discuss temporary vs permanent weakness risk - Mention heterotopic ossification risk and prophylaxis - Document discussion in medical record - DVT prophylaxis per ACSQHC guidelines {/* SECTION 15: EXAM CHEAT SHEET */}

Hip Anterolateral Approach (Watson-Jones)

Hip Anterolateral Approach (Watson-Jones)