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 */} ### Imaging Gallery {/* MISSING IMAGE: /images/topics/hip-anterior-approach-smith-petersen/web-sourced/1-consolidated-standards-for-reporting-trials-flow-d.png {/* MISSING IMAGE: /images/topics/hip-anterior-approach-smith-petersen/web-sourced/1-consolidated-standards-for-reporting-trials-flow-d.png */} */} {/* SECTION 2: EXAM WARNING */} **True internervous plane** between TFL (superior gluteal nerve) and sartorius (femoral nerve). This makes the approach safe for extensive dissection without motor nerve injury risk. The interval is between rectus femoris medially and TFL laterally in the deep plane. **Lateral femoral cutaneous nerve** crosses the surgical field lateral to medial. Injury causes meralgia paresthetica (anterolateral thigh numbness). Incidence 10-20%. Identify and protect or accept division with patient counseling. The **femoral nerve, artery, and vein** lie medial to sartorius. Excessive medial retraction or prolonged retractor pressure risks femoral nerve stretch injury. Use self-retaining retractors carefully and release periodically. Can be extended proximally with **iliofemoral extension** for full acetabular access (360 degrees). Requires detachment of external oblique from iliac crest and reflection of iliacus. Essential for acetabular fractures and complex reconstructions. {/* SECTION 2.5: QUICK DECISION GUIDE */} {/* SECTION 3: MNEMONICS */} {/* SECTION 4: OVERVIEW */} The **Smith-Petersen anterior approach** to the hip was first described by Marius Nygaard Smith-Petersen in 1917 for hip arthrodesis. It utilizes a true internervous plane between the tensor fasciae latae (superior gluteal nerve) and sartorius (femoral nerve), making it one of the safest approaches for extensive hip surgery. **Historical evolution:** - 1917: Original description by Smith-Petersen for arthrodesis - 1950s-1970s: Used for acetabular fractures and complex hip reconstruction - 2000s: Revival as Direct Anterior Approach (DAA) for total hip arthroplasty - Current: Standard for acetabular surgery, growing use for minimally invasive THA **Modern applications:** 1. **Total hip arthroplasty** - Direct Anterior Approach (DAA) variant 2. **Acetabular fracture fixation** - anterior column, anterior wall, both-column patterns 3. **Periacetabular osteotomy (PAO)** - for developmental dysplasia of hip 4. **Pediatric hip surgery** - DDH open reduction, pelvic osteotomies 5. **Hip arthroscopy** - anterior portal placement uses same landmarks The anterior approach is the only **true internervous plane** approach to the hip. This anatomical advantage makes it safe for extensive dissection and explains its continued use for complex acetabular work despite the learning curve required. {/* SECTION 5: ANATOMY/BIOMECHANICS */} **Surface anatomy:** - **ASIS** - primary landmark, palpable anteriorly - **Iliac crest** - extends posteriorly from ASIS - **Femoral pulse** - marks position of femoral artery (medial to field) - **Greater trochanter** - palpable laterally **Deep structures:** - **Rectus femoris** - two heads (straight and reflected) must be identified and retracted - **Hip capsule** - accessed between rectus and TFL after muscle retraction - **Iliopsoas** - lies on medial aspect of capsule - **Ascending branch of lateral circumflex femoral artery** - between TFL and rectus, requires ligation **Acetabular anatomy (for extensile exposure):** - **Anterior column** - from iliac crest to pubic symphysis - **Anterior wall** - anterior rim of acetabulum - **Quadrilateral plate** - medial wall visualization possible - **Ilioinguinal ligament** - released for distal extension {/* SECTION 6: CLASSIFICATION SYSTEMS */} **True Internervous Plane:** The approach exploits the interval between the **Tensor Fasciae Latae** (myotome L4-S1) and the **Sartorius** (myotome L2-L3). **Approach Variants Classification:** The approach variant chosen depends primarily on the indication and required exposure. **LFCN Anatomical Variations (Sartorius Classification):** The lateral femoral cutaneous nerve has significant anatomical variability, impacting surgical planning. Pre-operative counseling about LFCN injury risk is essential given the variable anatomy. **Acetabular Fracture Classification (Judet-Letournel):** For acetabular work via this approach, understand the fracture patterns. **Elementary types (5):** - Anterior wall - Anterior column - Posterior wall - Posterior column - Transverse **Associated types (5):** - Both-column - T-shaped - Transverse + posterior wall - Anterior column/posterior hemitransverse - Anterior wall/posterior hemitransverse **Smith-Petersen approach (with iliofemoral extension) is indicated for:** - Anterior column fractures - Anterior wall fractures - Both-column fractures - Anterior column + posterior hemitransverse **Both-column fractures** are the most common associated acetabular fracture pattern (25%). Despite involving both columns, they can often be treated via an extended Smith-Petersen alone because fixing both columns to the intact ilium stabilizes the fracture without requiring posterior access. {/* SECTION 7: CLINICAL ASSESSMENT */} **Preoperative Patient Selection:** **Ideal candidates for anterior approach THA:** - BMI under 35 (obesity increases difficulty) - Normal femoral anatomy (not severe retroversion/valgus) - No previous anterior hip surgery - Preserved hip flexion (over 90 degrees) - Primary arthroplasty (revisions more challenging) **Physical examination findings:** - Hip range of motion assessment - Flexion contracture evaluation - Leg length discrepancy measurement - Neurovascular status (especially LFCN distribution) - Skin quality over anterior approach **Contraindications/caution:** - Morbid obesity (BMI over 40) - Severe femoral retroversion or valgus deformity - Proximal femoral hardware or deformity - Previous anterior approach surgery - Ankylosed hip Careful patient selection optimizes outcomes for anterior approach THA. **History and mechanism:** - High-energy trauma (dashboard injury, fall from height) - Associated injuries (Letournel: 40% have other significant injuries) - Time from injury (ideally surgery within 5-14 days) - Medical optimization status **Physical examination:** - Hemodynamic stability (retroperitoneal hemorrhage common) - Sciatic nerve function (10% of posterior fracture-dislocations) - Skin integrity (Morel-Lavallee lesion assessment) - Associated lower extremity injuries **Red flags requiring urgent intervention:** - Open fracture - Irreducible dislocation - Sciatic nerve deficit with displaced fragment - Vascular compromise Red flags require urgent surgical intervention within 24-48 hours. **Clinical assessment:** - Walking pattern (if ambulatory) - Leg length discrepancy - Range of motion assessment - Galeazzi sign (leg appears short in flexion) - Trendelenburg test **Age-specific considerations:** - 6-18 months: Open reduction candidacy - 18 months - 6 years: PAO or Pemberton consideration - Over 6 years: Salvage procedures (shelf, Chiari) **Imaging correlation required:** - Ultrasound (under 6 months) - AP pelvis radiograph - CT arthrography for surgical planning Imaging modality selection is age-dependent for pediatric DDH assessment. {/* SECTION 8: INVESTIGATIONS */} **Imaging Assessment:** **Standard views:** - AP pelvis (bilateral comparison) - Lateral hip (cross-table or frog-leg) - Judet views for acetabular fracture (obturator oblique, iliac oblique) **What to assess:** - Femoral anteversion (templating) - Acetabular version and coverage - Bone quality (osteoporosis indicators) - Previous hardware or deformity **Indications:** - Acetabular fractures (essential for classification) - Complex deformity (DDH, Paget's) - Revision surgery planning - 3D reconstruction for surgical planning **Key information:** - Fracture pattern and displacement - Marginal impaction assessment - Fragment size and location - Sciatic buttress involvement **Additional Investigations:** **Preoperative Laboratory Studies:** - Full blood count (hemoglobin, platelets) - Coagulation screen (for trauma) - Group and hold (THA) or cross-match (trauma) - Renal function (contrast/medication adjustment) - Blood glucose (diabetes optimization) For **acetabular fractures**, CT with 3D reconstruction is mandatory for surgical planning and approach selection. The Judet radiographs are useful for initial classification but CT provides the definitive assessment of fracture pattern, marginal impaction, and posterior wall integrity. {/* SECTION 9: MANAGEMENT ALGORITHM */} **Decision Algorithm - Approach Selection:** THA: Consider DAA variant. Acetabular fracture: Smith-Petersen with extension. DDH reconstruction: Classic Smith-Petersen. Combined pathology: Plan extensile approach. BMI and body habitus. Previous surgery and scarring. Bone quality and anatomy. Medical comorbidities. Expected compliance. Learning curve consideration (DAA: 30-50 cases). Equipment availability (fracture table, specialized retractors). Team familiarity with approach. Backup plan if difficulties encountered. Template implants (THA). Plate and screw selection (fracture). Fluoroscopy requirements. Table and positioning needs. The decision pathway should systematically address all factors before committing to approach selection. **Approach Selection by Indication:** Choose the approach based on surgeon experience and patient-specific factors. **Relative contraindications to anterior approach:** Consider alternative approaches when encountering: - Revision THA with significant proximal femoral bone loss - Periprosthetic fracture extending to greater trochanter - Infection with planned debridement and implant exchange - Severe femoral deformity requiring osteotomy - Previous anterior approach with extensive scarring In these scenarios, posterior or lateral approaches provide better exposure and are safer options. Recognizing when NOT to use the anterior approach is as important as knowing when to use it. {/* SECTION 10: INDICATIONS */} **Direct Anterior Approach (DAA) for THA:** **Ideal candidates:** - Young, active patients seeking faster recovery - Normal to increased femoral anteversion - Non-obese patients (BMI under 35 preferred) - Primary THA with normal anatomy **Relative contraindications:** - Severe obesity (BMI over 40) - difficult femoral exposure - Severe retroversion or valgus femur - challenging femoral preparation - Previous anterior hip surgery - scarring complicates dissection - Severe flexion contracture - limits femoral access **Advantages:** - True muscle-sparing approach - Lower dislocation risk (theoretically) - Faster early recovery and mobilization - Supine positioning allows bilateral procedures **Disadvantages:** - Steep learning curve (30-50 cases) - Limited femoral exposure (difficult revisions) - LFCN injury risk - Specialized table/equipment often used This approach has gained significant popularity as the DAA for THA due to perceived faster recovery, though long-term outcomes are similar to other approaches. **Gold standard for anterior acetabular access:** **Ideal fracture patterns:** - Anterior column fractures - Anterior wall fractures - Both-column fractures (can access both columns) - T-type fractures (with posterior approach) **Surgical approach:** Standard Smith-Petersen with **iliofemoral extension**: - Allows 360-degree acetabular visualization - Access to inner and outer tables - Quadrilateral plate visualization - Superior dome visualization **Key steps for fracture work:** 1. Expose anterior column along pelvic brim 2. Detach external oblique from iliac crest for proximal extension 3. Reflect iliacus from inner table 4. Visualize fracture lines and reduction 5. Apply reconstruction plate along pelvic brim The extensile nature of this approach makes it essential for acetabular fracture surgeons. **Developmental dysplasia of hip (DDH):** **Procedures via anterior approach:** - Open reduction of DDH (age 6-18 months) - Pemberton osteotomy (acetabuloplasty) - Periacetabular osteotomy (PAO) - adolescents and adults - Shelf procedures for acetabular dysplasia **Advantages in children:** - Excellent acetabular exposure - Safe plane (no motor nerve risk) - Can address both femoral and acetabular pathology - Lower infection risk than medial approach **Technical considerations:** - LFCN in children is more medial - protect carefully - Smaller working space requires fine instruments - Cartilage injury risk at margins of capsulotomy This is the standard approach for most pediatric hip reconstruction procedures. **Additional uses:** **Tumor resection:** - Access to anterior iliac tumors - Combined with lateral window for total hip reconstruction after tumor **Hip arthrodesis:** - Historical indication (Smith-Petersen's original use) - Wide exposure for joint preparation and fixation - Rarely performed in modern practice **Iliopsoas tenotomy:** - Symptomatic iliopsoas impingement after THA - Lesser trochanter access **Hip arthroscopy portal placement:** - Anterior portal uses same internervous plane - Familiarity with anatomy reduces neurovascular injury risk The versatility of this approach explains its continued relevance across subspecialties. {/* SECTION 7: PATIENT POSITIONING */} **Patient position: Supine** - General or spinal anesthesia - Ensure adequate muscle relaxation - Discuss with anesthesia team: hypotensive technique for trauma (reduced blood loss) - Standard operating table or specialized fracture/arthroplasty table - For THA: Some surgeons use specialized DAA table with femoral positioner - For fracture: Standard table with C-arm access - Occiput padded - Arms positioned on arm boards (abducted under 90 degrees) - Sacrum and heels padded - Non-operative leg: slight hip flexion and abduction - C-arm from contralateral side for AP views - Ensure clear AP pelvis and lateral hip imaging possible - For fracture: inlet and obturator oblique views must be achievable - From umbilicus to mid-thigh - From midline anteriorly to posterior axillary line laterally - Chlorhexidine or betadine per protocol - Draping: Include anterior iliac crest and proximal thigh **Supine positioning** is a major advantage of the anterior approach: - Easier for anesthesia (better respiratory mechanics) - Allows **bilateral simultaneous procedures** for bilateral hip disease - C-arm access for intraoperative imaging without repositioning - Familiar positioning for surgical team reduces setup time {/* SECTION 11: SURGICAL TECHNIQUE */} ### Surface Landmarks and Incision **Palpable landmarks:** - ASIS (anterior superior iliac spine) - primary landmark - Greater trochanter - lateral and distal - Femoral pulse - medial (marks neurovascular bundle) **Incision options:** **Standard Smith-Petersen (for acetabular work):** - Start 2cm distal and lateral to ASIS - Curve distally and laterally toward greater trochanter - Length: 10-15cm (can extend as needed) - Stays lateral to neurovascular bundle **Direct Anterior Approach (DAA) for THA:** - Longitudinal incision between ASIS and greater trochanter - Length: 8-10cm for minimally invasive technique - Centered over palpable interval between TFL and sartorius Keep incision **lateral to the femoral pulse**. Medial deviation risks injury to femoral neurovascular structures. Mark the femoral pulse before draping and plan incision lateral to this. ### Superficial Layer Dissection **Step 1: Incise skin and subcutaneous tissue** - Deepen through subcutaneous fat using cutting diathermy - Ligate or cauterize superficial vessels - Look for LFCN in subcutaneous layer **Step 2: Identify and manage LFCN** - Runs from lateral to medial, usually 1-2cm distal to ASIS - Variable anatomy: may pass under, through, or lateral to inguinal ligament - **Options:** (1) identify and retract medially (preserve), or (2) divide and bury if tented - Counsel patient preoperatively about meralgia paresthetica risk (10-20%) **Step 3: Identify fascia and muscular interval** - Identify fascia lata and fascia over TFL - Palpate interval between TFL (lateral - taught, band-like) and sartorius (medial - softer) - Mark interval with electrocautery The **LFCN is not always identifiable** despite careful dissection. Variable anatomy means it may be subfascial or have multiple branches. Some surgeons accept division and counsel patients preoperatively. Others use a more medial skin incision to avoid it entirely. ### Deep Interval Development **Step 1: Open fascia in line with interval** - Incise fascia between TFL (lateral) and sartorius (medial) - Interval typically easy to identify by palpation - Extend incision proximally to just below inguinal ligament **Step 2: Develop internervous plane** - Blunt dissection between TFL and sartorius - This is a true internervous plane: TFL (superior gluteal), sartorius (femoral) - Place retractors: self-retaining with care, or hand-held initially **Step 3: Identify and manage rectus femoris** - Rectus lies deep in the interval - Two heads: straight head (AIIS) and reflected head (superior acetabular rim) - For **THA**: retract rectus medially with iliopsoas - For **acetabular work**: may need to release reflected head for better visualization **Step 4: Ligate ascending branch of LCFA** - **Lateral circumflex femoral artery** ascending branch runs between rectus and TFL - Must be identified and ligated for hemostasis - Use ties or clips - avoid diathermy near nerve - This is a consistent bleeder if not addressed early The **femoral nerve** lies medial to the operative field deep to sartorius. Excessive medial retraction or prolonged retractor pressure causes stretch neuropraxia. Manifest as postoperative quadriceps weakness and loss of knee extension. **Prevention**: Use self-retaining retractors cautiously, release periodically, minimize medial retraction force. A clear understanding of the deep anatomy is essential for safe execution of this approach. ### Hip Capsule Exposure and Capsulotomy **Step 1: Reflect muscles from capsule** - Retract TFL laterally - Retract sartorius and rectus femoris medially - Identify anterior hip capsule **Step 2: Hip capsulotomy pattern** **For THA:** - Capsular release: T-shaped or inverted L - Longitudinal limb along femoral neck - Transverse limb along acetabular rim - Excise or preserve capsule per surgeon preference **For acetabular fracture:** - Limited capsulotomy or capsulectomy - Goal is exposure of anterior column and acetabular rim - May need to release reflected head of rectus **For pediatric DDH:** - Anterior capsular flap based superiorly - Preserve capsule for closure - Open transversely to visualize femoral head **Step 3: Identify key landmarks** - Femoral neck anteriorly - Acetabular rim superiorly - Transverse acetabular ligament and labrum - Ligamentum teres (if preserved) Capsular management is **controversial in THA**. Some surgeons excise anterior capsule for better exposure and lower dislocation risk (rare in anterior approach anyway). Others preserve and repair capsule for improved stability and proprioception. The capsulotomy pattern depends on the indication and surgeon preference for capsular repair. ### Femoral Exposure (for THA/Hip Arthroplasty) **Challenge: Limited femoral access compared to posterior/lateral approaches** **Step 1: Position hip for femoral exposure** - **Extend hip** by dropping leg off side of table or using femoral positioner - **Externally rotate** hip to bring proximal femur into field - Flexion of hip relaxes anterior structures for neck osteotomy **Step 2: Perform femoral neck osteotomy** - In situ osteotomy with oscillating saw - Cut at predetermined level (preoperative templating) - Remove femoral head with corkscrew or bone hook **Step 3: Access femoral canal** - Place bent Hohmann retractor around proximal femur - Elevate proximal femur anteriorly - Externally rotate and extend hip to bring femur into operative field - Use specialized femoral elevator/positioner if available **Step 4: Prepare femoral canal** - Broach or ream per implant system - **Limited visualization** - rely on tactile feedback and fluoroscopy - Higher learning curve than posterior approach for femoral preparation **Pitfalls:** - **Proximal femoral fracture** during broaching due to limited visualization - **Varus stem position** if not carefully aligned - **Wound extension required** in difficult cases (muscular patients, abnormal anatomy) Femoral exposure is the **limiting factor** in anterior approach THA. Difficult in: - Muscular patients with large thighs - Obese patients (BMI over 35) - Severe retroversion or valgus femur - Revision surgery with proximal femoral bone loss Be prepared to extend wound or convert to alternate approach in difficult cases. Mastery of femoral exposure techniques is critical for successful anterior approach THA. ### Iliofemoral Extension (for Acetabular Fracture Work) **Indication: Full acetabular visualization for fracture fixation** **Step 1: Proximal extension of skin incision** - Extend incision proximally along iliac crest - Can curve posteriorly to greater sciatic notch if needed - Subperiosteal dissection along iliac crest **Step 2: Detach external oblique from iliac crest** - Release abdominal muscles (external oblique, internal oblique, transversus) from iliac crest - Elevate anteriorly to expose inner table of ilium - Preserve lateral cutaneous nerve of thigh (iliohypogastric) **Step 3: Reflect iliacus from inner table** - Subperiosteal dissection of iliacus from inner pelvic wall - Work from lateral to medial - Exposes **pelvic brim and quadrilateral plate** **Step 4: Visualize acetabulum** - Full 360-degree visualization possible - Anterior column along pelvic brim - Anterior wall and dome - Posterior column (limited - may need separate incision) - Quadrilateral plate medially **Step 5: Fracture reduction and fixation** - Reduce fracture with pointed reduction forceps - Temporary K-wire fixation - Apply reconstruction plate along pelvic brim (typical for anterior column) - Multiple screw fixation into columns **Both-column acetabular fractures** can often be treated via extended Smith-Petersen alone. The fracture is "fixed" when both columns are stabilized to the intact ilium. Lag screw across posterior column into intact ilium plus plate on anterior column achieves this without posterior approach. The extensile capability of this approach makes it invaluable for complex acetabular reconstruction. **Primary risks:** 1. **LFCN** - crosses field from lateral to medial under inguinal ligament. Injury rate 10-20% causing meralgia paresthetica. 2. **Femoral nerve** - lies medial to sartorius. Stretch injury from excessive medial retraction causes quadriceps weakness and loss of knee extension. 3. **Lateral circumflex femoral vessels** - deep branch (ascending) runs between rectus and TFL. Must be ligated for hemostasis. 4. **Superior gluteal nerve** - lateral to TFL, rarely injured if staying in superficial plane. **Vascular:** - **Ascending branch of lateral circumflex femoral artery**: Consistent bleeder in the interval. - **Femoral Artery**: Medial to sartorius, at risk with excessive medial retraction. **Nerve:** - **LFCN**: Most common injury (sensory). - **Femoral Nerve**: Motor injury (quadriceps). {/* SECTION 12: CLOSURE */} **Wound closure:** - **If preserved**: Repair capsule with interrupted absorbable sutures - **If excised**: Proceed to fascial closure (for THA) - **For fracture/pediatric**: Always repair capsule for stability - Repair TFL-sartorius interval if opened widely - Usually not necessary for limited THA incision - Use absorbable suture (0 or 1 Vicryl) - Close dead space with 2-0 Vicryl - Ensure hemostasis - anterior approach can have significant bleeding - Drain placement controversial (author preference for acetabular fracture, not for THA) - Subcuticular 3-0 Monocryl or skin staples - Skin adhesive or sterile strips - Waterproof dressing {/* SECTION 12: COMPLICATIONS */} **LFCN injury management:** - Most recover spontaneously over 6-12 months - Temporary numbness common, permanent in 5-10% - Neuropathic pain (less common) may require gabapentin or nerve block - Surgical exploration rarely indicated **Femoral nerve stretch injury:** - Presents as quadriceps weakness and loss of knee extension - Usually neuropraxia - recovers over weeks to months - EMG at 3-4 weeks if no recovery to confirm neuropraxia vs axonotmesis - Knee brace for stability during recovery - Physiotherapy for quadriceps strengthening **Preoperative counseling** should specifically mention: - LFCN injury risk (10-20%) and meralgia paresthetica symptoms - Possibility of quadriceps weakness (femoral nerve) - Longer learning curve for surgeon (if within first 30-50 cases) - Potential for wound extension or approach conversion in difficult cases Informed consent is particularly important for elective anterior approach THA given these specific risks. {/* SECTION 13: POSTOPERATIVE CARE */} **Postoperative Protocol by Indication:** **Day 0-1 (Immediate postoperative):** - Early mobilization: same day or day 1 - **No hip precautions** required (advantage of anterior approach) - Weight bearing as tolerated with walker or crutches - DVT prophylaxis: Aspirin 100mg BD or rivaroxaban 10mg daily - Multimodal analgesia: paracetamol, NSAIDs (if appropriate), opioids PRN - Ice and elevation **Day 1-14 (Early recovery):** - Progress to cane or single crutch - Physiotherapy: gait training, hip strengthening - Wound check at day 14 - Remove staples/sutures at 14 days **Week 2-6 (Rehabilitation):** - Wean walking aids (typically by week 4-6) - Progressive strengthening exercises - Activity modification as tolerated - Drive when off narcotics and safe (typically 4-6 weeks) **6 weeks and beyond:** - Review with X-ray - Return to full activities as tolerated - Sports typically allowed 3-6 months postoperatively The absence of hip precautions facilitates faster functional recovery compared to posterior approach. **Immediate (Day 0-2):** - Bed rest 24-48 hours - DVT prophylaxis essential (enoxaparin 40mg daily) - Heterotopic ossification prophylaxis: indomethacin 75mg daily for 3 weeks OR radiation (700cGy single dose) - Pain management: multimodal analgesia - Hemodynamic monitoring (retroperitoneal bleeding) **Week 1-6:** - Touch weight bearing (maximum 10kg) for 6 weeks minimum - Early ROM exercises (passive then active) - DVT prophylaxis continues 4-6 weeks - Serial X-rays at 2, 6, 12 weeks **Week 6-12:** - Progress weight bearing based on X-ray healing - Partial weight bearing if bridging callus visible - Full weight bearing typically by 12 weeks - Physiotherapy for strengthening **Long-term:** - Risk of post-traumatic arthritis (10-50% depending on injury) - THA may be required (typically 5-20% at 10 years) - Monitor for heterotopic ossification symptoms Anatomic reduction and HO prophylaxis are the two most important factors for long-term outcome. **DDH Open Reduction (Infant/Toddler):** - Hip spica cast immediately postoperatively - Cast duration: 3 months (typically 6 weeks in "human position" then 6 weeks in abduction) - Parents education on cast care and positioning - Close follow-up with serial imaging **Periacetabular Osteotomy (Adolescent/Adult):** - Touch weight bearing for 6 weeks - CPM or early ROM exercises - DVT prophylaxis for 4-6 weeks - Progress to full weight bearing by 8-12 weeks - Return to sports 4-6 months **Key monitoring:** - Acetabular remodeling assessment - Femoral head coverage improvement - Pain and function improvement Serial imaging confirms adequate coverage and guides return to activity decisions. Unlike posterior approach THA, **anterior approach THA does not require hip precautions**. Patients can flex, adduct, and internally rotate without restriction. This contributes to faster early recovery and improved patient satisfaction in the first 6 weeks. {/* SECTION 14: OUTCOMES/PROGNOSIS */} **Expected Outcomes by Indication:** **THA Approach Comparison - Registry Data (AOANJRR 2023):** {/* MISSING IMAGE: /images/topics/hip-anterior-approach-smith-petersen/web-sourced/1-consolidated-standards-for-reporting-trials-flow-d.png {/* MISSING IMAGE: /images/topics/hip-anterior-approach-smith-petersen/web-sourced/1-consolidated-standards-for-reporting-trials-flow-d.png */} */} **Key registry findings:** - Anterior approach: 15% of primary THA in Australia - Posterior approach: 60% of primary THA - **Revision rates similar** across approaches at 10 years when performed by experienced surgeons - Dislocation rates: Anterior 0.6% less than Posterior 2-3% (without repair) - Learning curve evident: higher complication rates in first 30-50 cases **Prognosis Factors:** - Experienced surgeon (over 50 anterior cases) - Appropriate patient selection (BMI under 35) - Primary procedure (not revision) - Good bone quality - Anatomic reduction (fracture) - Surgeon learning curve (under 30 cases) - Obesity (BMI over 35) - Complex anatomy or revision - Marginal impaction (fracture) - Delayed surgery over 14 days (fracture) **Long-term Considerations:** - **THA survivorship**: 95% at 10 years, 80% at 20 years (approach independent) - **Post-traumatic arthritis**: 15-50% after acetabular fracture (dependent on reduction quality) - **Heterotopic ossification**: Higher with anterior/extensile approaches - prophylaxis recommended - **Functional outcomes**: Anterior approach shows faster early recovery (6 weeks) but equivalent at 1 year **No approach is superior for THA** when performed by experienced surgeons. The anterior approach offers lower dislocation rates and faster early recovery, but these advantages are offset by LFCN injury rates and learning curve complications. Registry data shows equivalent 10-year revision rates across all approaches. {/* SECTION 11: EVIDENCE BASE */} {/* SECTION 17: VIVA SCENARIOS */} {/* SECTION 13: MCQ PRACTICE */} **Q: What is the internervous plane in the Smith-Petersen anterior approach to the hip?** A: Between **tensor fasciae latae** (supplied by superior gluteal nerve) and **sartorius** (supplied by femoral nerve). This is a true internervous plane with no motor nerve at risk within the interval. **Q: What is the most common nerve injury in anterior approach hip surgery and what are the symptoms?** A: **Lateral femoral cutaneous nerve (LFCN)** injury occurs in 10-20% of cases. Symptoms are meralgia paresthetica: anterolateral thigh numbness and dysesthesia. This is a pure sensory nerve, so no motor weakness occurs. **Q: What structure lies between the tensor fasciae latae and sartorius in the deep dissection and must be managed during exposure?** A: **Rectus femoris** with its two heads (straight head from AIIS and reflected head from superior acetabular rim). The **ascending branch of lateral circumflex femoral artery** runs between rectus and TFL and must be ligated. **Q: What are the main indications for the Smith-Petersen anterior approach with iliofemoral extension?** A: **Acetabular fracture fixation** (anterior column, both-column patterns), **periacetabular osteotomy for DDH**, and **complex hip reconstruction**. The extensile nature allows 360-degree acetabular visualization. **Q: How do you prevent femoral nerve injury during anterior approach hip surgery?** A: The femoral nerve lies **medial to the field** deep to sartorius. Prevent injury by: (1) avoiding excessive medial retraction, (2) releasing self-retaining retractors periodically, (3) keeping dissection in the lateral interval, and (4) protecting during closure. {/* SECTION 14: AUSTRALIAN CONTEXT */} **Local considerations:** - Anterior approach THA (DAA) has variable adoption across Australia - Major arthroplasty centers often have surgeons trained in DAA - Learning curve considerations for emerging surgeons - AOANJRR tracks approach-specific outcomes **Medicolegal considerations:** - **Informed consent** must specifically mention LFCN injury risk - Document discussion of meralgia paresthetica (10-20% incidence) - Mention possibility of wound extension or approach conversion for difficult femoral exposure - Standard precautions for DVT prophylaxis per ACSQHC guidelines **Equipment availability:** - Specialized DAA tables available at major centers - Standard operating table adequate for Smith-Petersen for acetabular work - Familiarity with equipment before attempting approach {/* SECTION 15: EXAM CHEAT SHEET */}

Hip Anterior Approach (Smith-Petersen)

Hip Anterior Approach (Smith-Petersen)