import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: 15-30mm posterior to hip joint capsule, exits pelvis below piriformis (85%) or through it (15%), descends posterolateral to ischial tuberosity **Protection**: Keep hip flexed during external rotator release (relaxes nerve), gentle tissue handling, preserve quadratus femoris muscle, avoid excessive inferior dissection, check nerve if excessive bleeding from medial femoral circumflex artery **Injury Rate**: 0.5-2% transient, less than 0.5% permanent (foot drop, sensory loss) **Location**: 30-50mm proximal to greater trochanter, exits pelvis above piriformis through greater sciatic foramen, runs between gluteus medius and minimus **Protection**: Avoid proximal dissection beyond greater trochanter, stay inferior to safe zone (5cm above GT), limit superior retractor placement, no dissection above piriformis **Injury Rate**: Less than 0.5% (Trendelenburg gait, abductor weakness) **Location**: 30-50mm medial to anterior hip joint, lies on iliopsoas muscle, femoral nerve lateral, artery central, vein medial **Protection**: Stay on bone with anterior acetabular retractors, avoid medial perforation during reaming, careful with anterior screw placement, no excessive medial wall reaming **Injury Rate**: Rare less than 0.1% (catastrophic if occurs) **Location**: Branches from profunda femoris, runs posteriorly between external rotators, supplies femoral head and short external rotators **Protection**: Control bleeding with electrocautery, avoid excessive stripping of short external rotators, ligate if needed **Injury Rate**: Common minor bleeding source (rarely significant) **Location**: Variable position 20-50mm medial to ASIS, crosses iliacus muscle, runs under inguinal ligament medial to ASIS **Protection**: Minimize anterior dissection, protect if visible during direct anterior or anterolateral approaches **Injury Rate**: 1-2% (meralgia paresthetica - lateral thigh numbness) ### Relevant Surgical Anatomy **Superficial Layers** - **Skin and Subcutaneous Tissue**: Variable thickness, increased in obese patients - **Fascia Lata/IT Band**: Dense fibrous layer overlying gluteus maximus, incised longitudinally in line with fibers - **Gluteus Maximus**: Large muscle with oblique fibers (superomedial to inferolateral), innervated by inferior gluteal nerve, split bluntly in line with fibers **Deep Layers - Short External Rotators (Superficial to Deep)** 1. **Piriformis**: Most superior, inserts superior GT, sciatic nerve landmark 2. **Superior Gemellus + Obturator Internus + Inferior Gemellus**: Form conjoined tendon, insert medial GT 3. **Quadratus Femoris**: Most inferior, broad muscle, preserve if possible 4. **Obturator Externus**: Deep to quadratus, not typically encountered **Posterior Hip Capsule** - Thick fibrous capsule with longitudinal fibers along femoral neck - Superior capsule most important for stability (iliofemoral ligament anteriorly) - Capsular repair critical to reduce dislocation risk **Neurovascular Structures** - **Sciatic Nerve**: Exits pelvis below (or through) piriformis, descends 15-30mm posterior to capsule - **Superior Gluteal Neurovascular Bundle**: Exits above piriformis, supplies gluteus medius/minimus - **Inferior Gluteal Neurovascular Bundle**: Exits below piriformis, supplies gluteus maximus - **Medial Femoral Circumflex Artery**: Runs between external rotators, major blood supply to femoral head **Internervous Plane** - Between superior gluteal nerve (gluteus medius/minimus) and inferior gluteal nerve (gluteus maximus) - Splitting gluteus maximus preserves inferior gluteal nerve - True internervous plane between superior gluteal nerve and sciatic nerve (not commonly used) **Acetabular Landmarks** - **Transverse Acetabular Ligament**: Bridges inferior acetabulum, marks true floor and guides version - **Anterior/Posterior Columns**: Provide structural support for cup - **Medial Wall**: Thin bone, avoid excessive reaming (protrusio risk) **Femoral Landmarks** - **Greater Trochanter**: Insertion site for external rotators (posterior), abductors (superior/lateral) - **Lesser Trochanter**: 1cm above = standard neck cut level - **Femoral Shaft Axis**: Guides stem anteversion (10-15 degrees) ### Indications for Total Hip Replacement **Absolute Indications** - **Primary Osteoarthritis**: Failed conservative management (NSAIDs, physiotherapy, injections), severe pain affecting quality of life, radiographic evidence (joint space loss, osteophytes, subchondral sclerosis/cysts) - **most common 85% of THR** - **Avascular Necrosis**: Ficat stage III-IV with femoral head collapse, failed core decompression, secondary osteoarthritis - **Femoral Neck Fracture**: Displaced Garden III/IV in elderly (greater than 65 years), failed fixation, pre-existing arthritis - **Inflammatory Arthritis**: Rheumatoid arthritis, ankylosing spondylitis with severe joint destruction - **Post-traumatic Arthritis**: Following acetabular fracture, femoral neck fracture, hip dislocation **Relative Indications** - **Developmental Dysplasia**: Severe dysplasia (Crowe III-IV), secondary arthritis, pain - **Protrusio Acetabuli**: Medial wall deficiency, secondary to rheumatoid arthritis, osteomalacia - **Slipped Capital Femoral Epiphysis**: Severe deformity, secondary arthritis in young adults - **Perthes Disease Sequelae**: Severe femoral head deformity, secondary arthritis - **Failed Previous Surgery**: Failed osteotomy, failed hemiarthroplasty, failed resurfacing ### Approach-Specific Indications for Posterior Approach **Ideal Scenarios** - **Primary Total Hip Replacement**: Excellent all-around approach for routine cases - **Complex Acetabular Exposure Needed**: Superior visualization for difficult cup positioning - **Revision Surgery**: Extensile approach allows proximal extension for acetabular revision - **Post-acetabular Fracture**: Familiar anatomy for surgeons who perform fracture surgery - **All Body Habitus**: Works in obese, muscular, thin patients (unlike DAA which difficult in obese) **Advantages Over Other Approaches** - Familiar anatomy (most common approach taught in training) - Excellent acetabular visualization (easier cup positioning than lateral or anterior) - Extensile (can extend proximally for revision, complex acetabular work) - Lower femoral fracture risk than DAA (especially in learning curve) - Works in all body types ### Contraindications **Absolute Contraindications** - **Active Infection**: Septic arthritis, soft tissue infection, bacteremia - stage for two-stage revision - **Inadequate Bone Stock**: Severe osteoporosis with fracture risk, consider cemented fixation - **Patient Cannot Participate**: Severe dementia (cannot follow precautions), non-ambulatory (bed-bound) - **Medical Unfit**: ASA 4-5, severe cardiac/respiratory disease, recent MI/stroke **Relative Contraindications** - **Previous Infection**: Remote infection, increased risk of recurrence - **Neuropathic Joint**: Charcot arthropathy, diabetes, syphilis - high failure rate - **Abductor Deficiency**: Polio, muscular dystrophy - consider constrained liner - **Previous Posterior Approach**: Recurrent posterior dislocation - consider anterior or dual mobility - **Young Active Patient**: Consider anterior approach (faster recovery, no precautions) - **Morbid Obesity**: BMI greater than 40, higher complication rate (wound, infection, dislocation) **Approach-Specific Contraindications** - **Recurrent Posterior Dislocation**: If previous posterior approach, consider switching to anterior or using dual mobility - **Cannot Comply with Precautions**: Cognitive impairment, psychiatric, non-compliant - consider anterior (no precautions) - **Previous Sciatic Nerve Injury**: Relative contraindication, increases re-injury risk ### Pre-operative Equipment Checklist **Positioning Equipment** - **Lateral Positioners**: Beanbag OR anterior/posterior pelvic supports (peg system) - **Pelvic Alignment Device**: C-arm OR alignment guide to confirm perpendicular pelvis - **Padding**: Gel pads for axilla (brachial plexus), lateral knee (peroneal nerve), ankle (pressure ulcer) - **Arm Support**: Elevated arm board or pillow support - **Table**: Standard operating table with ability to extend/flex **Retraction System** - **Self-Retaining Retractor**: Charnley hip retractor OR Omni-Tract system - **Hohmann Retractors**: Curved retractors in multiple sizes (anterior, superior, inferior acetabulum) - **Bent Hohmann**: Curved posterior neck retractor for femoral exposure - **Army-Navy Retractors**: Superficial tissue retraction **Acetabular Instrumentation** - **Reamers**: Hemispherical reamers in 2mm increments (40-66mm typical range) - **Reamer Driver**: High-torque power driver - **Cup Trials**: Match reamer sizes - **Cup Inserter**: With alignment guide (40° inclination, 20° anteversion markings) - **Impactor and Mallet**: For cup insertion - **Screws**: If using supplemental fixation (6.5mm cancellous screws typical) **Femoral Instrumentation** - **Box Chisel**: Opens femoral canal (anteromedial calcar bone removal) - **Broaches**: Progressive sizes matching stem system (typically sizes 1-15) - **Broach Handle**: With anteversion guide markings - **Broach Impactor and Mallet**: For progressive broaching - **Trial Stems and Heads**: Variable neck lengths (-4mm to +12mm typical) - **Stem Inserter**: For final stem impaction - **Head Impactor**: For Morse taper head insertion **Cutting and Preparation** - **Oscillating Saw**: For femoral neck osteotomy - **Corkscrew or Femoral Head Clamp**: For head removal - **Curettes**: For acetabular cartilage and labrum removal - **Pulsed Lavage**: For canal preparation - **Suction and Irrigation**: High-volume suction **Suture Materials** - **Heavy Ethibond #2**: For tagging external rotators - **Absorbable #2 Vicryl**: For capsular repair - **Absorbable #1 Vicryl**: For fascia closure - **Absorbable 2-0 Vicryl**: For subcutaneous layer - **Skin Closure**: Staples OR absorbable subcuticular 3-0 monocryl **Implant Systems** - **Acetabular Cup**: Uncemented hemispherical porous-coated shell (titanium, tantalum, or trabecular metal) - **Liner**: Polyethylene (highly cross-linked XLPE), ceramic, or dual mobility - **Femoral Stem**: Uncemented metaphyseal-filling (most common) OR cemented (elderly, osteoporotic) - **Femoral Head**: Modular head (cobalt-chrome, ceramic, oxidized zirconium) - size 28-40mm, typical 32-36mm **Adjuncts** - **Tranexamic Acid**: 1-2g IV at induction (reduces blood loss) - **Antibiotics**: Cefazolin 2g IV pre-incision (vancomycin if MRSA risk) - **Local Infiltration**: Ropivacaine, ketorolac, epinephrine cocktail (periarticular injection for post-op pain) ### Operating Room Setup **Patient Position**: Lateral decubitus, affected side superior - Pelvis perpendicular to table (critical - confirm with C-arm or alignment device) - Anterior pelvic support at ASIS/pubis - Posterior support at sacrum - Padding: axilla, lateral knee (peroneal nerve), malleolus - Secure with beanbag or peg system - Operating table flexed 10-15 degrees at hip (opens exposure) **Surgical Team Positioning** - **Primary Surgeon**: Posterior to patient - **Assistant**: Anterior (retraction) or posterior (alongside surgeon) - **Scrub Nurse**: Behind surgeon with instrument table **Imaging** - **C-arm**: Available for position check, trial reduction check (optional) - **Intra-operative X-ray**: Some surgeons confirm cup position and leg length ### Step 1: Patient Positioning and Landmarks **Positioning Sequence** - General OR spinal anesthesia (spinal reduces blood loss) - Lateral decubitus position, affected side superior - Secure pelvis PERPENDICULAR to table - critical for cup orientation - Anterior support at pubis/ASIS (pelvic positioner or beanbag) - Posterior support at sacrum - Padding at ALL bony prominences: axilla (brachial plexus), lateral knee (peroneal nerve), malleolus, dependent hip - Secure with beanbag (evacuated) OR pelvic positioning device - Confirm perpendicular pelvis with C-arm AP view OR alignment guide - Hip initially in slight flexion/adduction **Surface Landmarks** - **Iliac Crest**: Superior pelvic landmark - **ASIS**: Anterior reference point - **PSIS**: Posterior reference point - **Greater Trochanter**: Most prominent landmark, center of incision - **Femoral Shaft Axis**: Extend line distally from GT - **Ischial Tuberosity**: Posterior inferior landmark **Skin Preparation** - Chlorhexidine-alcohol prep (superior to povidone-iodine) - Prep entire hip from iliac crest to knee - Draping: four-corner drape OR hip drape with pouch **Exam Key**: Lateral decubitus with pelvis PERPENDICULAR is critical for acetabular component orientation. Any pelvic rotation causes systematic cup malposition (common cause of dislocation). Confirm perpendicularity with C-arm AP pelvis view or alignment device. Greater trochanter is primary landmark - most prominent bony point in lateral position. - **Pelvic Rotation**: Causes systematic cup anteversion/retroversion error, leg length discrepancy - **Inadequate Padding**: Brachial plexus palsy (axilla), peroneal nerve palsy (fibular head - most common), pressure ulcers - **Patient Instability**: Risk of fall from table during positioning or surgery - **Hypotension**: Lateral position can cause hypotension, communicate with anesthesia ### Step 2: Skin Incision and Fascia Lata **Incision** - Posterior curvilinear OR straight incision (both acceptable) - **Start**: 10cm proximal to GT, along line toward PSIS - **Middle**: Curve posteriorly over GT (most prominent point) - **End**: Extend 10-15cm distally along femoral shaft axis - **Total Length**: 20-25cm (shorter in thin patients, longer in obese) - Deepen through subcutaneous tissue with electrocautery - Identify and incise **fascia lata/IT band** longitudinally in line with fibers - Expose underlying gluteus maximus muscle belly **Key Technical Points** - Incision in lateral position is essentially vertical (posterior curve when patient supine) - Center over GT - palpate as most prominent bony point - Posterior curve allows access to external rotators - Fascia lata incised IN LINE with fibers (parallel to incision), not perpendicular **Exam Key**: Incision centered over greater trochanter - most reliable landmark in lateral position. Posterior curve provides access to short external rotators. Fascia lata incised longitudinally in line with fibers (minimizes bleeding, easier closure). Visible gluteus maximus has characteristic oblique muscle fiber orientation (superomedial to inferolateral). - **Too Anterior**: Enters vastus lateralis muscle, misses joint, difficult acetabular access - **Too Posterior**: Difficult femoral exposure, potential sciatic nerve exposure - **Excessive Length**: Unnecessary for most cases, poor cosmesis - **Fascia Cut Perpendicular**: Increases bleeding, more difficult repair ### Step 3: Gluteus Maximus Splitting **Splitting Technique** - Identify gluteus maximus muscle fibers (oblique orientation: superomedial to inferolateral) - Split muscle BLUNTLY in line with fibers using: - Finger dissection (classic technique) - Mayo scissors spread technique - Combination of both - Split typically in mid-substance of muscle - Split length 8-10cm - Insert self-retaining retractor (Charnley hip retractor) to hold split open - Minimal bleeding if done correctly in line with fibers **Deep Exposure** - Splitting exposes deeper layer: fat and fascia overlying short external rotators - Remove fat and bursa with electrocautery and sponge - Expose underlying external rotator muscles and tendons **Anatomic Notes** - This is **intermuscular** splitting, NOT internervous plane (gluteus maximus has single nerve - inferior gluteal) - True internervous plane is between gluteus medius/minimus (superior gluteal nerve) and gluteus maximus (inferior gluteal nerve) **Exam Key**: Gluteus maximus split BLUNTLY in line with oblique fibers (superomedial to inferolateral orientation). This is intermuscular, not internervous (single nerve supply from inferior gluteal nerve). Blunt splitting preserves muscle fibers and minimizes bleeding. Self-retaining retractor maintains exposure. Deeper layer shows fat and external rotator fascia. - **Perpendicular to Fibers**: Significant bleeding, muscle damage, poor healing - **Excessive Proximal Extension**: Risk to superior gluteal neurovascular bundle (30-50mm above GT) - **Inferior Gluteal Artery Injury**: Rare but can cause significant bleeding - **Inadequate Split**: Poor exposure, difficulty with deeper dissection ### Step 4: Identification of External Rotators **Anatomic Identification** Remove overlying fat and bursa. Identify **short external rotators** (superior to inferior): 1. **PIRIFORMIS** (Superior Landmark) - Most superior rotator - Inserts on superior-medial GT - Sciatic nerve exits pelvis below it (85%) or through it (15%) - Superior gluteal neurovascular bundle above it - Key landmark for safe dissection 2. **SUPERIOR GEMELLUS + OBTURATOR INTERNUS + INFERIOR GEMELLUS** (Conjoined Tendon) - Form thick conjoined tendon - Obturator internus tendon central component - Both gemelli sandwich OI tendon - Insert on medial GT as single unit 3. **QUADRATUS FEMORIS** (Inferior Landmark) - Most inferior rotator - Broad, flat, quadrilateral muscle - Sciatic nerve runs on anterior surface - **Preserve if possible** to protect sciatic nerve **Posterior Capsule** - Visible deep to external rotators - Longitudinal fibers along femoral neck - Will be released with or after rotators **Exam Key**: Short external rotators follow PIGOQ sequence: Piriformis (superior), Inferior gemellus, [obturator internus], Obturator externus (deep), Quadratus femoris (inferior). Piriformis is critical landmark - sciatic nerve below it, superior gluteal nerve above it. Preserve quadratus femoris to protect sciatic nerve which runs on its anterior surface. - **Sciatic Nerve**: Runs under (or through) piriformis, descends posterior to rotators - injury risk 0.5-2% - **Superior Gluteal Nerve**: Above piriformis, excessive proximal dissection causes injury (Trendelenburg gait) - **Medial Femoral Circumflex Artery**: Runs between rotators, bleeding common during dissection - **Misidentification**: Confusing rotators leads to incomplete release or excessive tissue damage ### Step 5: External Rotator Release **Hip Positioning for Release** - Flex hip 60-90 degrees - Internally rotate hip 20-30 degrees - This position brings external rotators under tension (easier to identify and release) - **Keeps sciatic nerve relaxed** (hip flexion reduces tension on nerve) **Release Technique** 1. **Incise 1cm from GT Insertion** - Leaves cuff of tendon on bone for later repair - Use knife or heavy scissors - Can release individually or en masse 2. **Tag Released Tendons** - Use heavy Ethibond #2 suture - Tag piriformis separately - Tag conjoined tendon (OI/gemelli) - Tags facilitate later identification for repair 3. **Preserve Quadratus Femoris** - Leave attached to femur if possible - Protects underlying sciatic nerve - Can release if needed for exposure but increases nerve risk 4. **Capsular Release** - Release posterior capsule with rotators OR - Release separately after rotators - T-shaped or inverted T capsulotomy **Alternative Techniques** - **Rotator-sparing**: Leave quadratus and superior gemellus attached (minimal release) - **Standard repair**: Release piriformis + conjoined tendon, repair both - **Extended release**: Include quadratus if needed (higher dislocation risk without repair) **Exam Key**: Release external rotators 1cm from GT insertion - leaves CUFF for repair (critical to reducing dislocation risk from 5% to 1-2%). TAG with heavy Ethibond #2 suture for identification during repair. Hip flexion and internal rotation puts rotators under tension AND relaxes sciatic nerve. Preserve quadratus femoris when possible (protects sciatic nerve). - **Sciatic Nerve Injury**: Too much inferior dissection, hip extension during release, aggressive retraction - **Releasing Too Close to GT**: Inadequate tissue for robust repair, increases dislocation risk - **Not Tagging Tendons**: Difficult to identify for repair, may miss repair (high dislocation risk) - **Premature Capsule Breach**: Uncontrolled entry into joint, risk of iatrogenic acetabular damage ### Step 6: Posterior Capsulotomy **Capsulotomy Technique** - Incise posterior capsule along femoral neck - **T-shaped capsulotomy** (preferred): - Superior limb along superior femoral neck - Inferior limb along inferior femoral neck - Posterior vertical limb - **Inverted T variation**: Horizontal then vertical - **Cruciate capsulotomy**: Some surgeons prefer cross pattern **Capsule Management** - **Preserve for Repair** (modern approach): - Tag capsule with absorbable sutures - Mark superior and inferior leaves - Repair during closure - **Excise** (historical approach): - Higher dislocation risk - Not recommended with current evidence **Joint Entry** - Capsulotomy exposes femoral head and neck - Assess joint condition: confirms diagnosis (OA, AVN, fracture) - Assess bone quality **Exam Key**: Posterior capsulotomy T-shaped or inverted T. Capsule REPAIR critically important to reduce dislocation risk - modern evidence shows enhanced repair (capsule + rotators) reduces dislocation from 5% to 1-2%. Superior capsule most important for stability. Tag capsule with sutures if planning repair for easier identification. - **Sciatic Nerve**: Posterior to capsule, aggressive posterior dissection risks injury - **Superior Gluteal Nerve**: Excessive proximal capsular dissection risks injury - **Inadequate Capsulotomy**: Poor exposure, difficulty with head removal and acetabular access - **Uncontrolled Capsule Tear**: Irregular edges difficult to repair ### Step 7: Femoral Neck Osteotomy **Pre-cut Assessment** - Assess femoral neck and head in situ - Confirm templated neck cut level - Measure from lesser trochanter (standard: 1cm above LT) - Consider pre-operative template **Neck Osteotomy Technique** - Use oscillating saw - Cut perpendicular to anatomic neck axis (NOT shaft axis) - Angle approximately 45 degrees to femoral shaft - Cut from anterior-superior to posterior-inferior - Protect posterior soft tissues during cutting **Neck Cut Level** - **Standard**: 1cm above lesser trochanter - **Higher cut**: Reduces offset (avoid unless necessary) - **Lower cut**: Preserves offset but risks stem seating difficulty **Femoral Head Removal** - Insert corkscrew into head - Remove with twisting and gentle traction - Alternative: femoral head clamp - Avoid excessive force (risk posterior wall fracture, femoral shaft fracture) **Head Processing** - **ALWAYS send for culture** (even if no clinical infection suspicion - 1-2% unexpected positive) - Send for histology if indicated - Measure head size: approximates cup outer diameter minus 8-10mm (wall thickness) **Exam Key**: Neck cut 1cm above lesser trochanter (standard) - higher cut reduces offset (abductor dysfunction, impingement), lower cut risks seating difficulty. Cut perpendicular to anatomic neck, not shaft (approximately 45° to shaft). ALWAYS send head for culture even without infection suspicion - 1-2% unexpected positive cultures. Head size guides cup sizing. - **Cut Too High**: Reduced offset, abductor dysfunction, femoral impingement - **Cut Too Low**: Difficulty seating stem, increased fracture risk during broaching - **Posterior Wall Fracture**: Excessive force removing head, inadequate soft tissue protection - **Femoral Shaft Fracture**: Pulling too hard on head, osteoporotic bone ### Step 8: Acetabular Exposure **Hip Positioning - FADER Position** - **F**lexion: 90-110 degrees - **AD**duction: 30-40 degrees across body - **(aD)duction**: Emphasis on adduction - **E**xternal rotation: 20-30 degrees - **R**otation: Combined position brings acetabulum anterior/superior into optimal view **Retractor Placement** - **ANTERIOR retractor**: Hohmann over anterior wall/ilium (stay on bone - femoral vessels nearby) - **SUPERIOR retractor**: Hohmann over superior rim - **INFERIOR retractor**: Hohmann over transverse ligament/inferior rim (watch sciatic nerve) - Self-retaining system holds retractors **Acetabular Preparation** - Remove labrum circumferentially with electrocautery - Remove pulvinar (fatty tissue) from cotyloid fossa - Identify **transverse acetabular ligament** (TAL) at inferior rim: - Marks true acetabular floor - Guides version (parallel to TAL = native version ~20°) - Prevents excessive inferior reaming **Exposure Quality Check** - Entire acetabular rim visible - Can see anterior column, posterior column, dome, medial wall - Adequate visualization for reaming and cup insertion **Exam Key**: FADER position (Flexion-ADduction-External Rotation) brings acetabulum into optimal view. Three Hohmann retractors around rim (anterior, superior, inferior). Transverse acetabular ligament (TAL) is critical landmark - marks TRUE FLOOR, guides VERSION (parallel to TAL = ~20° anteversion). Posterior approach provides EXCELLENT acetabular visualization (advantage over anterior/lateral approaches). - **Anterior Retractor Slips**: Into pelvis, risk of iliac vessel injury (catastrophic) - **Posterior Wall Fracture**: Dysplastic acetabulum, severe OA with thin posterior wall, excessive retraction - **Sciatic Nerve**: Inferior retractor pressure, especially with leg flexion/adduction - **Inadequate Retraction**: Poor visualization, cup malposition, reaming errors ### Step 9: Acetabular Reaming **Reamer Selection** - Start with reamer 2-4mm smaller than templated size - Progressive reaming in 2mm increments - Ream until appropriate size for adequate coverage **Reaming Technique** - Position reamer to match native anatomy initially - Ream to subchondral bone - look for **BLEEDING DOT SIGN**: - Speckled appearance of healthy bleeding bone - Confirms adequate reaming depth - Uniform across acetabulum - Target position: **40° inclination** (abduction from horizontal), **20° anteversion** (relative to body) - Use TAL as version reference (parallel to TAL = 20° anteversion) **Reaming Progression** - Sequential reaming with increasing sizes - Ream until good **RIM FIT** (70-80% contact) - Final reamer typically 1-2mm smaller than cup size (**LINE-TO-LINE** or slight underreaming) - Avoid excessive **MEDIAL** reaming: - Causes protrusio - Weakens medial wall - No benefit for fixation **Special Situations** - **Dysplasia**: May need to ream more laterally (lateralize hip center) - **Protrusio**: Avoid medial reaming, may need bone graft - **Previous fracture**: Altered anatomy, use landmarks carefully **Exam Key**: Ream to BLEEDING DOT SIGN (speckled subchondral bone). Target position 40° inclination, 20° anteversion (Lewinnek safe zone 30-50° / 10-30°). TAL guides version - parallel to TAL = ~20° anteversion. Final reamer 1-2mm smaller than cup for press-fit (line-to-line). Posterior approach advantage: excellent visualization makes accurate reaming easier than other approaches. - **Excessive Medial Reaming**: Medial wall fracture/perforation, protrusio, intrapelvic penetration - **Posterior Wall Fracture**: Thin posterior wall (dysplasia, severe OA), excessive reaming - **Under-reaming**: Inadequate bone contact, poor press-fit, micromotion, loosening - **Cup Malposition**: Most common technical error - causes dislocation, impingement, accelerated wear ### Step 10: Cup Insertion and Fixation **Cup Selection** - Select cup 1-2mm LARGER than final reamer (interference fit for press-fit) - Confirm correct size and type - Attach inserter with alignment guide **Cup Insertion** - Align cup to target position: - 40° inclination (abduction) - 20° anteversion - Use inserter alignment guide markings - Impact with mallet: - Progressive firm taps - Avoid excessive force (fracture risk) - Listen for change in sound (pitch increases when seated) - Seat cup flush with acetabular rim - Assess stability - no toggling or micromotion **Supplemental Screw Fixation** - **Indications for screws**: - Poor bone quality (osteoporosis) - Large cup (greater than 60mm) - Inadequate initial press-fit stability - Dysplastic acetabulum - Revision surgery - **Screw safe zones** (right hip, clock face): - **SAFE**: Posterosuperior quadrant (10 o'clock to 2 o'clock) - **DANGEROUS**: Anteroinferior (3 o'clock to 9 o'clock - external iliac vessels) - **DANGEROUS**: Posteroinferior (7 o'clock to 9 o'clock - sciatic nerve) - **Screw technique**: - Use depth guide (typically 20-25mm length) - Confirm screw not prominent (impingement risk) - Usually 2-3 screws sufficient **Cup Position Verification** - Visual assessment of position - Some surgeons use intra-operative imaging - Check for prominent screws **Exam Key**: Cup 1-2mm larger than final reamer = press-fit fixation. Target 40° inclination / 20° anteversion (Lewinnek safe zone). Screws indicated for poor bone quality, large cups, inadequate press-fit. Safe zone posterosuperior (10-2 o'clock right hip). Avoid anteroinferior (iliac vessels) and posteroinferior (sciatic nerve). Modern screws have depth markings. - **Cup Malposition**: Main cause of dislocation in posterior approach (outside safe zone) - **Medial Wall Perforation**: During impaction, especially if over-reamed - **Intrapelvic Screw Penetration**: Vascular injury (external iliac), visceral injury (bladder, bowel) - **Screw Impingement**: Screw head contacts femoral neck/stem (component damage, metallosis) ### Step 11: Femoral Canal Preparation **Femoral Dislocation** - Dislocate femur ANTERIORLY - Hip flexion + external rotation brings femur into wound - May need to release more capsule if tight - Use curved Hohmann retractor around posterior femoral neck (protects soft tissues) **Canal Opening** - Use box chisel to remove anteromedial calcar bone - Opens femoral canal entrance - Facilitates broach entry - Avoid excessive calcar removal (fracture risk) **Broaching Technique** - Start with broach 2-3 sizes smaller than templated - Progressive broaching with sequential sizes - Broach in slight valgus alignment (avoid varus - fracture risk) - Broach until **CORTICAL CHATTER**: - Feel/hear contact with endosteal cortical bone - Indicates good fit - Should be uniform around broach **Broach Depth** - Broach to planned depth - Broach handle typically 0-5mm above neck cut surface - Final broach determines final stem depth **Anteversion Assessment** - Confirm stem anteversion 10-15° (some systems have guides on broach handle) - Combined with cup anteversion 20° = total anteversion 30-35° (prevents impingement) **Canal Quality Check** - Good cortical contact - No fractures - Adequate depth - Appropriate anteversion **Exam Key**: Dislocate anteriorly with flexion/external rotation. Box chisel removes anteromedial calcar bone and opens canal. Broach until CORTICAL CHATTER = good press-fit. Broach depth determines final stem depth (should be fully seated). Target anteversion 10-15° (combined with cup 20° = total 30-35°). Avoid varus broaching (fracture risk). - **Periprosthetic Femur Fracture**: 1-3% risk, increased with varus preparation, excessive force, osteoporosis, elderly - **Femoral Perforation**: Varus broaching, cortical breach, especially in elderly/osteoporotic bone - **Calcar Fracture**: Excessive box chiseling, osteoporotic bone - **Undersized Stem**: Subsidence, thigh pain, loosening, early failure ### Step 12: Trial Reduction and Stability Testing **Trial Component Insertion** - Insert trial stem (matches final broach size) - Insert trial head (variable neck lengths available: -4, 0, +4, +8, +12mm typical) - Insert liner into cup: - Clean cup taper thoroughly - Impact liner until loud **SNAP** (Morse taper engagement) - Confirm fully seated **Hip Reduction** - Reduce trial hip - May require traction and manipulation - Should reduce with reasonable force **Four Key Assessment Parameters** **1. STABILITY** (Most Important in Posterior Approach) - Test in all positions, especially: - **Posterior dislocation position**: Flexion 90° + adduction + internal rotation - **Anterior dislocation position**: Extension + adduction + external rotation (rare) - Hip should be stable through full ROM without excessive force - If unstable: - Increase head size - Increase offset (longer neck) - Check for impingement (bony or component) - Rarely: revise cup position **2. LEG LENGTH** - Compare to pre-operative templating - Compare to contralateral leg (knee height, malleoli level) - Measure from fixed pelvic point (ASIS, iliac crest) to medial malleolus - Target: 5mm lengthening OR equal to contralateral - Patient tolerance: most tolerate up to 10mm lengthening **3. OFFSET** - Adequate soft tissue tension - Abductor tension (feel for appropriate tightness) - No clunking with motion - Adequate offset critical for abductor function and stability **4. RANGE OF MOTION** - **Flexion**: 110-120° (should achieve 90° minimum) - **Extension**: 10-20° - **Abduction**: 45° - **Adduction**: 30° - **Internal rotation**: 45° - **External rotation**: 45° - No impingement in any position **Adjustments** - **If unstable**: Larger head, longer neck, check impingement - **If leg too long**: Shorter neck, check stem depth - **If leg too short**: Longer neck, check stem seating - **If inadequate offset**: Larger head, longer neck, lateralized cup **Exam Key**: Trial reduction tests four parameters: STABILITY (most critical in posterior), LEG LENGTH, OFFSET, ROM. Stability test: flex 90° + adduct + internally rotate (posterior dislocation position) - should remain stable. Adjust with head size/neck length. Target 5mm lengthening or match contralateral. Offset affects abductor tension. Most common patient complaint = leg length discrepancy. - **Unrecognized Instability**: Leads to postoperative dislocation (2-5% without repair, 1-2% with enhanced repair) - **Leg Length Discrepancy**: Most common medicolegal issue in THR - **Impingement**: Bony (osteophytes, retained cement) or component (neck-liner, cup-GT) causes squeaking/instability - **Trial Liner Not Seated**: Pulls out during testing, confuses assessment ### Step 13: Final Component Implantation **Dislocate Trial Components** - Carefully dislocate trial reduction - Remove trial head - Remove trial stem **Liner Insertion** - Clean cup taper thoroughly (dry gauze) - Position liner correctly (some have anti-rotation tabs) - Impact liner firmly until loud **SNAP**: - Morse taper engagement - Typically requires 3-5 firm taps - Confirm fully seated (visual, tactile assessment) - Some cups have secondary locking mechanisms (check system-specific instructions) **Femoral Canal Preparation for Final Stem** - Clean and **DRY** canal thoroughly: - Suction all blood and fluid - Brush canal - Dry with gauze sponges - Critical for uncemented fixation - Final inspection for fractures **Final Stem Insertion** - Insert final stem with impactor - Align to appropriate anteversion (10-15°) - Impact until seated: - Typically 1-2mm PROUD of final broach position - Subsides with impaction - Listen for pitch change (higher pitch = seated) - Confirm depth and alignment **Head Impaction** (Critical Step) - **Clean both tapers**: - Stem trunnion (male taper): dry gauze, inspect for debris - Head bore (female taper): dry gauze, inspect for debris - Critical - any debris causes taper corrosion - Position head on taper - Impact firmly with head impactor: - **12mm taper**: 5-6 firm hits - **Larger tapers**: 6-8 firm hits - Use proper impactor (not mallet on head directly) - **Adequate impaction critical** - prevents trunnionosis (taper corrosion, ALVAL, major cause of revision) **Final Inspection** - Confirm components correctly positioned - No debris in wound - Prepare for reduction **Exam Key**: Clean and DRY femoral canal critical for uncemented fixation. Liner must SNAP loudly into cup (Morse taper engagement). Final stem typically 1-2mm proud of broach (subsides with impaction). HEAD IMPACTION CRITICAL - clean BOTH tapers (stem trunnion and head bore), FIRM impaction prevents trunnionosis (taper corrosion, metallosis). Inadequate impaction = major cause of revision for ALVAL. - **Liner Malseating**: Intra-operative dislocation, liner fracture/dissociation, edge loading - **Femoral Fracture**: During final stem impaction, especially osteoporotic bone - **Inadequate Head Seating**: Trunnionosis (taper corrosion, ALVAL, metallosis) - major revision cause - **Contamination**: Infection risk if components handled improperly or dropped ### Step 14: Final Reduction and ROM Testing **Final Hip Reduction** - Bring femur from anterior position to posterior (anatomic position) - Gentle traction and manipulation - Should reduce with reasonable force (less than trial - components better fit) - Audible/tactile "clunk" when reduced **Comprehensive ROM Testing** - **Flexion**: 110-120° (minimum 90°) - **Extension**: 10-20° - **Abduction**: 45° - **Adduction**: 30° - **Internal rotation**: 45° - **External rotation**: 45° **Stability Testing** (Critical in Posterior Approach) - **Posterior dislocation test**: - Flex 90° + adduct + internally rotate - Apply posterior force on femur - Should remain stable without excessive force - **Anterior dislocation test**: - Extend + adduct + externally rotate - Rare direction but test - **Test throughout ROM**: No dislocation at any position **Leg Length Verification** - Measure from fixed pelvic point (ASIS or iliac crest) to medial malleolus - Compare to contralateral side - Acceptable: within 10mm of contralateral (target equal or 5mm longer) **Final Checks** - No impingement (bony or component) - Smooth motion through full ROM - Appropriate stability (stable but not overly tight) - Leg lengths acceptable - Document findings **Exam Key**: Final stability testing critical in posterior approach - historical dislocation rate 2-5% without capsular repair, reduced to 1-2% with modern enhanced repair. Key test position: flexion/adduction/internal rotation (posterior dislocation position). Hip should be stable but not overly tight (allows motion). Leg length measured from fixed pelvic landmarks (ASIS, iliac crest) to medial malleolus. - **Postoperative Dislocation**: Most common major complication in posterior approach (2-5% without repair) - **Unrecognized Leg Length Discrepancy**: Most common patient complaint and medicolegal issue - **Impingement**: Causes instability, squeaking, accelerated wear, patient dissatisfaction - **Overly Tight Hip**: Restricts motion, increases dislocation force but may cause pain ### Step 15: Enhanced Posterior Soft Tissue Repair **CRITICAL STEP** - Proper repair reduces dislocation from 5% to 1-2% **Repair Sequence** **1. Posterior Capsule Repair (Most Important)** - Identify tagged capsule edges (superior and inferior leaves) - Side-to-side repair using interrupted absorbable sutures (Vicryl #2) - 4-6 interrupted sutures typical - Create robust, tension-free repair - Superior capsule most important for stability **2. Short External Rotator Repair** - Identify tagged rotator tendons (Ethibond #2 tag sutures) - **Piriformis**: Repair to greater trochanter - **Conjoined tendon** (OI/gemelli): Repair to greater trochanter - Repair options: - **Bone tunnels**: Drill 2-3 holes in GT, pass sutures through - **Suture anchors**: Place in GT, attach rotators - **Trans-osseous**: Some systems allow direct bone fixation - Use heavy non-absorbable (Ethibond #2) or absorbable (Vicryl #2) suture - Create tight anatomic repair (restore original length-tension) **3. Combined Capsule-Rotator Repair** (Some Surgeons) - Repair conjoined tendon to posterior capsule - Creates double-layer repair - May provide additional stability **4. Quadratus Femoris** - If released: repair to femur - If preserved: leave intact (best option for nerve protection) **Evidence for Enhanced Repair** - Multiple RCTs show capsular repair reduces dislocation by 50-75% - Meta-analyses confirm benefit - Modern standard of care - NOT repairing capsule/rotators considered malpractice **Repair Assessment** - Test stability after repair - Should still achieve full ROM - No excessive tension (causes pain, stiffness) **Closure** - Close gluteus maximus with absorbable sutures (Vicryl #1) - Close fascia lata with absorbable sutures (Vicryl #1) - Subcutaneous layer: Vicryl 2-0 - Skin: Staples OR subcuticular absorbable monocryl 3-0 **Drains** - **Controversial**: Most surgeons avoid drains (increase infection risk) - If used: single drain, remove POD 1-2 **Exam Key**: Enhanced posterior repair CRITICAL - reduces dislocation from 5% to 1-2%. Repair CAPSULE first (most important - side-to-side with Vicryl #2), then EXTERNAL ROTATORS to greater trochanter (piriformis, conjoined tendon with bone tunnels or anchors). Create TIGHT anatomic repair. Multiple RCTs show capsular repair reduces dislocation by 50-75%. Not repairing is malpractice by modern standards. - **Inadequate Repair**: High dislocation risk (5% vs 1-2%) - **Repair Too Tight**: Restricts motion, causes pain, potential stiffness - **Not Repairing Capsule**: Main factor in postoperative dislocation - **Drains**: Increase infection risk (most surgeons avoid), potential for hematoma if no drain ### Immediate Postoperative Management (Day 0-2) **Recovery Room** - Neurovascular check (dorsalis pedis pulse, posterior tibial pulse, sciatic nerve function) - Pain control: multimodal analgesia (opioids, NSAIDs, acetaminophen, nerve blocks) - Antiemetics as needed - DVT prophylaxis initiated **Day 0 (Day of Surgery)** - Mobilize same day with physiotherapy (if medically stable) - **Weight bearing**: TDWB (toe-down weight bearing) OR WBAT (weight bearing as tolerated) - WBAT if good bone quality, uncemented press-fit, stable construct - TDWB if osteoporotic bone, cemented components, or concern for stability - **Hip Precautions** (Traditional Posterior Approach): - NO flexion greater than 90° - NO adduction past midline - NO internal rotation - Duration: 6 weeks minimum (some surgeons 12 weeks) - Use elevated toilet seat, avoid low chairs, sleep with abduction pillow **Day 1-2 (Discharge)** - Continue mobilization with PT/OT - Progress to walker or crutches - Discharge home (or rehab facility if needed) - Discharge criteria: - Medically stable - Adequate pain control - Safe mobility with assistive device - Understanding of precautions - Appropriate discharge destination ### Early Postoperative Period (Week 1-6) **Week 2** - Wound check and suture/staple removal (if non-absorbable used) - Assess for infection, dehiscence - Continue precautions - Progress mobility as tolerated **Week 6** - **X-rays**: AP pelvis and lateral hip - Assess component position - Check for subsidence, loosening - Measure leg lengths radiographically - Discontinue hip precautions if: - Good soft tissue repair - Radiographic stability - Patient understanding - Progress to full weight bearing if not already ### Medium-Term Recovery (3-6 Months) **Month 3** - Return to driving (earlier if right hip, adequate ROM and control) - Return to low-impact activities (golf, swimming, cycling) - Continue strength and ROM exercises **Month 6** - Return to impact sports (case-by-case, discuss risks) - Most patients at functional baseline - Continued improvement expected to 12 months ### Long-Term Follow-up **Annual Follow-up Lifelong** - Clinical assessment - X-rays (AP pelvis, lateral hip) - Monitor for loosening, wear, osteolysis - Assess function and satisfaction **DVT Prophylaxis** - **Duration**: 35 days (Australian guidelines) - **Options**: - LMWH (enoxaparin 40mg SC daily) - DOAC (rivaroxaban 10mg PO daily, apixaban 2.5mg BD) - Warfarin (target INR 2-3, less commonly used) - Mechanical prophylaxis: TED stockings, intermittent pneumatic compression **Infection Prophylaxis** - Perioperative antibiotics: cefazolin 2g IV pre-incision (3g if greater than 120kg) - Vancomycin 15mg/kg if MRSA risk - Continue 24 hours postoperatively (controversial - some single dose) ### Specific Precautions and Restrictions **Hip Precautions (6-12 weeks)** - Avoid flexion greater than 90° (use elevated toilet seat, avoid low chairs) - Avoid adduction past midline (sleep with abduction pillow between legs) - Avoid internal rotation (don't cross legs, avoid twisting) - **Rationale**: Prevents posterior dislocation while soft tissue repair heals **Driving** - Right hip: 6-8 weeks (when off opioids, adequate ROM and strength) - Left hip: 4-6 weeks (less demanding) **Return to Work** - Sedentary: 6-8 weeks - Light physical: 8-12 weeks - Heavy labor: 3-6 months (case-by-case) **Sexual Activity** - Resume at 6 weeks when precautions lifted - Avoid positions violating hip precautions **Impact Activities** - Low-impact (swimming, cycling, golf): 3 months - High-impact (running, tennis): Discuss risks, generally discourage - Contact sports: Generally discourage (high dislocation/fracture risk) ### Expected Outcomes (Australian AOANJRR Data) **Survival Rates** - **10-year revision rate**: ~5% for primary OA (uncemented) - **15-year revision rate**: ~8% for primary OA - Better outcomes: younger age, higher volume surgeon, uncemented fixation **Functional Outcomes** - **Pain relief**: Greater than 90% achieve excellent pain relief - **Function**: Most achieve independent mobility, return to activities of daily living - **Patient satisfaction**: 80-85% very satisfied, 10-15% satisfied with reservations **Common Reasons for Dissatisfaction** 1. Leg length discrepancy (most common) 2. Residual pain (often extra-articular source) 3. Reduced ROM 4. Instability/feeling of insecurity 5. Squeaking (ceramic-on-ceramic) 1. **Pellicci PM, Bostrom M, Poss R.** Posterior approach to total hip replacement using enhanced posterior soft tissue repair. *Clin Orthop Relat Res*. 1998;(355):224-228. doi:10.1097/00003086-199810000-00023 - Landmark RCT demonstrating capsular repair reduces dislocation from 5.8% to 0.6% after posterior approach THR 2. **Kwon MS, Kuskowski M, Mulhall KJ, Macaulay W, Brown TE, Saleh KJ.** Does surgical approach affect total hip arthroplasty dislocation rates? *Clin Orthop Relat Res*. 2006;447:34-38. doi:10.1097/01.blo.0000218746.84494.df - RCT confirming enhanced posterior repair significantly reduces dislocation risk 3. **Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR).** Hip, Knee & Shoulder Arthroplasty: 2023 Annual Report. Adelaide: AOA; 2023. - Comprehensive registry data showing 10-year revision rates ~5% for primary THR with uncemented fixation 4. **Lewinnek GE, Lewis JL, Tarr R, Compere CL, Zimmerman JR.** Dislocations after total hip-replacement arthroplasties. *J Bone Joint Surg Am*. 1978;60(2):217-220. - Classic study defining safe zone for acetabular component positioning (30-50° inclination, 10-30° anteversion) 5. **Berstock JR, Blom AW, Beswick AD, et al.** Mortality after total hip replacement surgery: a systematic review. *Bone Joint Res*. 2014;3(6):175-182. doi:10.1302/2046-3758.36.2000239 - Systematic review of mortality rates and risk factors following primary THR 6. **Suh KT, Park BG, Choi YJ.** A posterior approach to the hip with posterior soft-tissue repair for primary total hip replacement. *J Bone Joint Surg Br*. 2004;86(3):334-338. doi:10.1302/0301-620x.86b3.14432 - Study demonstrating capsular and external rotator repair reduces dislocation by 69% 7. **Meek RM, Allan DB, McPhillips G, Kerr L, Howie CR.** Epidemiology of dislocation after total hip arthroplasty. *Clin Orthop Relat Res*. 2006;447:9-18. doi:10.1097/01.blo.0000218754.12311.4a - Comprehensive review of dislocation epidemiology, risk factors, and prevention strategies 8. **Berry DJ, von Knoch M, Schleck CD, Harmsen WS.** Effect of femoral head diameter and operative approach on risk of dislocation after primary total hip arthroplasty. *J Bone Joint Surg Am*. 2005;87(11):2456-2463. doi:10.2106/JBJS.D.02860 - Large series demonstrating larger femoral heads (36mm vs 28mm) reduce dislocation risk 9. **Masonis JL, Bourne RB.** Surgical approach, abductor function, and total hip arthroplasty dislocation. *Clin Orthop Relat Res*. 2002;(405):46-53. doi:10.1097/00003086-200212000-00006 - Review of surgical approaches and their impact on abductor function and dislocation rates 10. **Therapeutic Guidelines Ltd.** eTG complete [digital]. Melbourne: Therapeutic Guidelines Limited; 2023. Available from: https://www.tg.org.au - Australian antibiotic guidelines for surgical prophylaxis and DVT prevention in orthopaedic surgery

Total Hip Replacement - Posterior Approach (Kocher-Langenbeck Modified)

Total Hip Replacement - Posterior Approach (Kocher-Langenbeck Modified)