import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, ComparisonTable, Timeline, TimelineItem, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, MedicalImage, Tabs, Tab } from '@/components/mdx' {/* SECTION 1: ONE-PAGER SUMMARY */} {/* SECTION 2: EXAM WARNING */} **Pain + Disability + Failed Conservative**. THA requires all three: (1) significant pain affecting quality of life, (2) functional disability, (3) adequate trial of non-operative management. Radiographic severity alone is not an indication. **50-80 years is optimal**. Younger patients (under 50) have higher lifetime revision risk and may benefit from hip preservation surgery. Older patients (over 80) have higher perioperative risk but excellent implant survival if they survive surgery. **Active infection is absolute**. Relative contraindications include: active medical comorbidities, poor bone stock, neuromuscular disease affecting function, patient unable to comply with rehabilitation, ongoing substance abuse. **AOANJRR data mandatory**. Know: (1) Over 50,000 THAs/year in Australia, (2) 95% survivorship at 15 years, (3) cemented femoral stems best in older patients, (4) bearing surface choice affects longevity. Quote registry data in viva. {/* SECTION 2.5: QUICK DECISION GUIDE */} {/* SECTION 3: MNEMONICS */} {/* SECTION 4: OVERVIEW */} **Total hip arthroplasty (THA)** is one of the most successful surgical procedures in modern medicine. The primary indication for THA is **end-stage hip arthritis** causing pain and disability that has failed conservative management. **Historical perspective:** - Sir John Charnley pioneered modern THA in the 1960s with the low-friction arthroplasty concept - Cemented metal-on-polyethylene became the gold standard - Evolution to modular implants, improved bearing surfaces, and minimally invasive techniques - Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) established 1999 - world-leading registry **THA works** because it: (1) reliably eliminates pain from arthritic hip, (2) restores function and mobility, (3) has predictable long-term outcomes with modern implants (95% survival at 15 years), (4) significantly improves quality of life. The key is **patient selection** - matching the right patient to the right procedure at the right time. **Epidemiology in Australia (AOANJRR 2023 data):** - Over 50,000 primary THAs performed annually in Australia - Increasing trend due to aging population - Bilateral THA common (10-15% of patients eventually need contralateral) - Male:Female ratio approximately 1:1.2 (OA slightly more common in women) - **Osteoarthritis**: 85-90% (primary or secondary) - **Avascular necrosis**: 5-10% - **Inflammatory arthritis**: 2-5% (RA, AS) - **Fracture sequelae**: 2-3% - **DDH and other**: 1-2% {/* SECTION 5: ANATOMY AND PATHOPHYSIOLOGY */} **Normal hip joint anatomy:** - Ball-and-socket joint with excellent stability and range of motion - Femoral head (2/3 sphere) articulates with acetabulum (horseshoe-shaped lunate surface) - Articular cartilage 2-4mm thick, allows load distribution and low-friction movement - Labrum deepens socket and creates suction seal - Capsule reinforced by ligaments (iliofemoral, pubofemoral, ischiofemoral) **Pathophysiology of osteoarthritis:** **Osteoarthritis is not just "wear and tear"**. It is an active disease process involving: (1) cartilage degradation (matrix metalloproteinases), (2) subchondral bone changes (sclerosis, cysts), (3) synovial inflammation, (4) osteophyte formation. The rate of progression is highly variable - some patients plateau, others progress rapidly. **Radiographic changes:** **Critical concept**: Radiographic severity does NOT always correlate with symptoms. Some patients have severe radiographic OA but minimal symptoms (do NOT offer surgery). Conversely, some have moderate radiographic changes but severe symptoms (may benefit from THA). **Symptoms drive the decision**, not X-rays alone. {/* SECTION 6: CLASSIFICATION SYSTEMS */} ### Tonnis Classification of Hip Osteoarthritis Tonnis Grade 3 is the most common indication for THA when combined with failed conservative treatment. ### Ficat/Steinberg Classification (Osteonecrosis) | Stage | Findings | THA Indication | |-------|----------|----------------| | I | MRI changes only, normal X-ray | Not indicated | | II | X-ray changes (sclerosis/cysts), no collapse | Not typically indicated | | III | Subchondral collapse (crescent sign) | Indicated | | IV | Secondary acetabular OA | Indicated | THA for AVN is indicated in Ficat Stage III-IV. Earlier stages may benefit from core decompression or free vascularized fibular grafting. ### Crowe Classification (Developmental Hip Dysplasia) | Type | Subluxation | Surgical Implications | |------|-------------|----------------------| | I | Under 50% | Standard THA usually possible | | II | 50-75% | May need small/offset components | | III | 75-100% | Specialized planning, possible shortening | | IV | Complete dislocation | High hip centre or subtrochanteric osteotomy | Higher Crowe grades require specialized preoperative templating and component selection. {/* SECTION 7: CLINICAL ASSESSMENT */} **History and physical examination for THA candidacy:** **History:** - **Pain characteristics**: Location (groin vs lateral), severity, progression - **Functional limitation**: Walking distance, stairs, ADLs, sleep disturbance - **Previous treatments**: Physio, injections, medications, duration and response - **Medical comorbidities**: Cardiac, pulmonary, diabetes, immunosuppression - **Patient goals**: Expectations for pain relief, function, activity level **Physical examination:** - **Gait**: Antalgic, Trendelenburg (abductor weakness), leg length discrepancy - **ROM**: Flexion, extension, abduction, adduction, internal/external rotation (IR lost first in OA) - **Leg length**: Measure true vs apparent LLD (ASIS to medial malleolus) - **Neurovascular**: Femoral/dorsalis pedis pulses, sensation, motor function - **Associated pathology**: Spine (flexion deformity), knee (referred pain pattern) **Patient-reported outcome measures:** - Oxford Hip Score (0-48, under 30 indicates severe impairment) - WOMAC (Western Ontario and McMaster Universities Arthritis Index) - HOOS (Hip disability and Osteoarthritis Outcome Score) - SF-36 (quality of life measure) {/* SECTION 8: INVESTIGATIONS */} **Imaging studies:** **Plain radiographs (essential):** - **AP pelvis** (standing, weight-bearing, both hips visible) - **Lateral hip** (cross-table or frog-leg) - **Findings**: Joint space narrowing, osteophytes, sclerosis, cysts - **Measurement**: Hip center, leg length, offset **Advanced imaging (selective):** - **MRI**: Early AVN detection (Stage I), soft tissue pathology, occult fracture - **CT scan**: DDH planning, post-traumatic deformity, bone stock assessment - **Nuclear medicine**: Bone scan for infection vs loosening differentiation (rare preoperative) **Laboratory investigations:** - **FBC**: Anemia (may need preoperative iron/EPO) - **UEC**: Renal function for NSAID use, perioperative hydration - **HbA1c**: If diabetic (target under 8%) - **ESR/CRP**: Elevated suggests infection (investigate before elective THA) - **Coagulation studies**: If on anticoagulation **Special investigations:** - **ECG**: All patients over 50 or with cardiac history - **Echocardiogram**: If cardiac symptoms or murmur - **Pulmonary function tests**: If severe COPD - **Urinalysis**: Rule out UTI before elective surgery {/* SECTION 9: INDICATIONS */} **Primary indication:** **End-stage hip arthritis causing pain and functional disability that has failed adequate conservative management.** **The Three Pillars of THA Indication:** 1. **Pain and Disability** - Pain that affects quality of life (sleep, ADLs, recreation) - Functional limitation (walking distance, stairs, getting out of chair) - Patient-reported outcome measures (HOOS, WOMAC, Oxford Hip Score) document severity 2. **Radiographic Evidence** - Plain radiographs show joint space loss, osteophytes, sclerosis, cysts - Confirms diagnosis but does NOT alone indicate need for surgery - Severity on X-ray does not correlate perfectly with symptoms 3. **Failed Conservative Treatment** - At least 6 months of appropriate non-operative management - Includes: physiotherapy, weight loss, activity modification, analgesia (NSAIDs, paracetamol), intra-articular injection - Patient compliance with conservative measures documented - **Severe OA** with pain, disability, failed conservative (most common) - **AVN Stage III-IV** with collapse and secondary OA - **Failed previous surgery** (ORIF for fracture, osteotomy) with persistent pain - **Acute femoral neck fracture** in elderly (hemiarthroplasty vs THA decision) - **Young patient** (under 50) with severe symptoms - weigh alternatives - **Inflammatory arthritis** (RA, AS) with hip involvement - **Post-traumatic arthritis** after acetabular fracture, dislocation - **DDH** with secondary arthritis - **Failed hip preservation** (PAO, femoral osteotomy) **Specific diagnostic categories:** ### Primary Osteoarthritis **Most common indication** (85-90% of THAs) **Presentation:** - Insidious onset of groin pain, may radiate to thigh/knee - Mechanical pain (worse with activity, better with rest) - Progressive stiffness (especially internal rotation lost first) - Gait changes (antalgic, Trendelenburg if abductors weak) **Radiographic criteria:** - Joint space narrowing (weight-bearing AP pelvis) - Osteophyte formation (femoral and acetabular) - Subchondral sclerosis - Subchondral cysts (geodes) **When to offer THA:** - Patient reports pain affecting sleep or ADLs - Walking distance limited (typically under 500m) - Failed 6 months of conservative treatment - Patient motivated for surgery and rehabilitation - Medical comorbidities optimized **Primary OA** = idiopathic, typically over 50 years, no clear cause. **Secondary OA** = identifiable cause such as DDH, AVN, SCFE, Perthes, post-traumatic. Important to distinguish because secondary OA may require specialized surgical planning (e.g., DDH needs high hip center restoration). ### Avascular Necrosis (AVN) **5-10% of THAs** **Classification (Ficat/Steinberg):** - **Stage I**: Normal X-ray, MRI changes only - **Stage II**: X-ray changes (sclerosis, cysts) but preserved contour - **Stage III**: Subchondral collapse (crescent sign) - **Stage IV**: Secondary acetabular arthritis **Indications for THA:** - **Stage III-IV**: Femoral head collapse or secondary OA → THA - **Stage I-II**: Consider hip preservation (core decompression, vascularized fibular graft) **Special considerations:** - Younger patient population (average age 40-50) - Often bilateral (stage contralateral hip) - Etiology affects prognosis (steroid-induced, alcohol, SCD, idiopathic) - Consider dual mobility bearing in young patient to reduce dislocation risk MRI positive, X-ray normal or early changes. **Treatment**: Core decompression, bisphosphonates, avoid risk factors. **Outcome**: Variable - may halt progression or continue to collapse. Subchondral collapse visible on X-ray (crescent sign). **Treatment**: THA. Core decompression no longer effective. **Outcome**: Excellent pain relief with THA. Acetabular involvement, advanced arthritis. **Treatment**: THA. **Outcome**: Standard THA, consider younger patient needs (dual mobility, hard-on-hard bearings). ### Inflammatory Arthritis **2-5% of THAs (RA, AS, psoriatic arthritis)** **Rheumatoid Arthritis (RA):** - Bilateral hip involvement common - Protrusio acetabuli (medial wall migration) common - Poor bone quality, osteoporosis from disease and medications - May need structural graft for protrusio - Cemented fixation often preferred due to bone quality **Ankylosing Spondylitis (AS):** - Hip involvement in 25-30% of AS patients - Severe stiffness, ankylosis - Risk of heterotopic ossification (HO) very high - prophylaxis mandatory - Spine fused - affects positioning, increases dislocation risk - May need osteotomy if severe flexion contracture **Preoperative considerations:** - Multidisciplinary approach (rheumatology) - Immunosuppressants - discuss perioperative management (stop methotrexate, continue biologics per guidelines) - DMARD use may affect wound healing and infection risk - Bilateral surgery often staged **Ankylosing spondylitis patients** have up to 70% risk of heterotopic ossification after THA. **Mandatory prophylaxis**: Indomethacin 75mg daily for 6 weeks OR single-dose radiation (7-8 Gy within 24 hours of surgery). Without prophylaxis, severe HO can cause ankylosis and loss of motion. ### Post-Traumatic Arthritis **Indications:** - Failed ORIF of femoral neck fracture (malunion, AVN, nonunion) - Post-acetabular fracture arthritis - Post-hip dislocation arthritis - Late sequelae of SCFE, Perthes disease **Challenges:** - Altered anatomy (previous hardware, malunion) - Retained hardware may need removal - Bone loss from trauma or previous surgery - Soft tissue scarring, contractures - Young patient population **Surgical planning:** - CT scan to assess bone stock and deformity - Plan for hardware removal (may need separate incision) - Consider structural grafting for bone defects - Anticipate difficult dissection due to scarring Post-traumatic THA requires careful preoperative planning and patient counseling about potential challenges. ### Developmental Dysplasia of Hip (DDH) **THA in DDH patients:** - Complex reconstructive procedure - Goals: (1) restore hip center to anatomic position, (2) achieve stable fixation - Challenges: bone deficiency, femoral anteversion, leg length inequality **Crowe Classification** (hip subluxation): - **I**: Less than 50% subluxation - **II**: 50-75% subluxation - **III**: 75-100% subluxation - **IV**: Complete dislocation (no contact) **Surgical considerations:** - **Acetabulum**: High hip center vs anatomic center with structural graft - **Femur**: Shortening osteotomy if Crowe III-IV to avoid nerve stretch - **Specialized implants**: Small cups, dysplasia stems - **Templating essential**: Anticipate cup size, medialization needs In **Crowe III-IV DDH** with high dislocation, attempting to restore anatomic hip center can stretch the sciatic nerve more than 4cm, causing palsy. **Solution**: Femoral shortening osteotomy (remove 2-4cm of proximal femur) to allow hip center restoration without nerve stretch. {/* SECTION 10: CONTRAINDICATIONS */} **Active infection anywhere in the body** is an absolute contraindication to elective THA. This includes: (1) local hip infection (previous septic arthritis), (2) distant infection (UTI, dental abscess, skin infection), (3) bacteremia. **Why**: Risk of hematogenous seeding to prosthetic joint. **Management**: Eradicate infection first, minimum 6 weeks antibiotics, inflammatory markers normal before proceeding. **Special contraindication scenarios:** **Not absolute contraindication** but need careful discussion: - Lifetime revision risk high (50-year-old may need 2-3 revisions in lifetime) - Activity level typically higher (increased wear, loosening risk) - **Alternatives**: Hip arthroscopy, PAO, femoral osteotomy, resurfacing - If THA necessary: hard-on-hard bearings (ceramic-on-ceramic), dual mobility - **Counsel**: Revision likely, activity restrictions, long-term implications **High dislocation risk**: - Parkinson's disease (rigidity, bradykinesia, falls) - CVA with spasticity, weakness - Cerebral palsy, muscular dystrophy - **Mitigation strategies**: Dual mobility bearing, constrained liner, large diameter heads - Patient and family education about dislocation precautions - Consider if benefits outweigh risks (severe pain, immobility) {/* SECTION 11: PATIENT SELECTION */} **Patient selection is the single most important determinant of THA outcome.** **Ideal THA candidate:** - Age 50-80 years (optimal risk-benefit balance) - Severe symptomatic hip arthritis (pain, disability) - Failed adequate conservative trial (6+ months) - Motivated patient with realistic expectations - Able to participate in rehabilitation - Medical comorbidities optimized - Social support for postoperative period **Preoperative assessment:** - **History**: Pain severity, functional limitation, previous treatments, medical history - **Examination**: Hip ROM, leg length, gait, neurovascular, spine (fixed deformity) - **Imaging**: AP pelvis, lateral hip, assess arthritis severity - **Discussion**: Diagnosis, natural history, treatment options (conservative vs surgical) - Confirm failed conservative treatment (6 months minimum) - Patient-reported outcomes (HOOS, Oxford Hip Score) document severity - **Medical clearance**: Cardiac risk assessment (RCRI), pulmonary function if indicated - **Dental clearance**: Rule out infection source - **MRSA screening**: Nasal swab, decolonization protocol if positive - **Templating**: AP pelvis with magnification marker, template component sizes - **Consent**: Risks (infection 0.5-1%, dislocation 2-3%, DVT 1-2%, revision 5% at 15 years), benefits, alternatives - **Discuss**: Approach (anterior, posterior, lateral), bearing surface, fixation method - **Preoperative education**: DVT prophylaxis, mobility restrictions, rehabilitation expectations **Medical optimization:** - **RCRI score**: Revised Cardiac Risk Index (6 predictors) - High risk: Recent MI, CHF, CVA, DM, renal insufficiency, high-risk surgery - **Cardiology referral** if RCRI greater than or equal to 2 - Beta-blockers, statins perioperatively - Consider stress test if symptomatic - COPD: Optimize bronchodilators, stop smoking - OSA: CPAP compliance, perioperative monitoring - Respiratory infection: Defer surgery until resolved - **ABG/PFTs** if severe disease - **Diabetes**: HbA1c under 7% ideal, under 8% acceptable - Poor control increases infection risk 3-fold - **Anemia**: Iron studies, EPO if Hb under 110 g/L - **Renal**: Adjust medications, hydration protocol **HbA1c over 8%** is associated with significantly higher risk of surgical site infection, wound dehiscence, and periprosthetic joint infection. **Guidelines**: Ideally HbA1c under 7% before elective THA. If 7-8%, counsel about higher risk. If over 8%, strongly consider delaying surgery for 3 months of glycemic optimization. Emergency surgery (fracture) - proceed with heightened vigilance. **Dental clearance:** Recent dental infection or poor dentition can lead to bacteremia and hematogenous seeding of prosthetic joint. **Protocol:** - All patients: Dental examination within 6 months of THA - Active dental infection: Treat first, wait 6 weeks minimum - Poor dentition, multiple caries: Consider extraction and healing before THA - Routine dental prophylaxis: Per ADA guidelines (not routinely recommended for most patients, consider high-risk) **MRSA screening and decolonization:** Nasal swab for MRSA colonization (PCR test, results in 24-48 hours) **Decolonization protocol**: - Mupirocin nasal ointment (TID for 5 days) - Chlorhexidine body wash (daily for 5 days) - **Reswab** to confirm eradication If MRSA positive history: Vancomycin instead of cefazolin for prophylaxis {/* SECTION 12: PREOPERATIVE PLANNING AND TEMPLATING */} **Templating is essential** for: 1. Component size prediction (reduces operative time, inventory needs) 2. Leg length restoration planning 3. Offset restoration (abductor moment arm) 4. Identifying anatomical challenges (DDH, previous surgery, deformity) **Required radiographs:** - Standing, weight-bearing - Both hips visible, coccyx centered - **Magnification marker** (ball bearing of known size, typically 25mm or 30mm, at level of greater trochanter) - Pelvis level (obturator foramina symmetric) - Use to template acetabular component size and position - Cross-table lateral or frog-leg lateral - Assess femoral offset, canal shape - Identify deformity (previous fracture, Paget's) - Template femoral component size, neck cut level **Digital templating process:** Measure magnification marker on X-ray, input into software to calibrate (typically 110-120% magnification) - Mark hip center of rotation (COX point at intersection of lines) - Mark teardrop (medial acetabular wall landmark) - Mark lesser trochanter - Measure preoperative leg length (from COX to ischial tuberosity or iliac crest) - Place cup at anatomic hip center (teardrop plus 5mm medial, 25mm superior to teardrop) - Template covers subchondral bone, avoids protrusio or overmedialization - Note size (typically 50-58mm in adults) - Plan inclination (40-45 degrees) and anteversion (15-20 degrees) - Place stem in canal, fill metaphysis (press-fit) or 2mm gap (cemented) - Match native offset (distance from center of head to center of femoral canal) - Select neck length to restore leg length - Note stem size (typically 10-14 for uncemented, 2-4 for cemented) - Measure templated leg length (COX to ischial tuberosity) - Goal: Restore native length or up to 1cm lengthening if needed for stability - Over-lengthening (more than 1.5cm) risks nerve palsy, patient dissatisfaction - Document planned leg length to inform intraoperative measurement **Offset restoration:** **Offset** (distance from center of rotation to greater trochanter) affects abductor moment arm. **Leg length** affects limb length equality. They are **independent but related**. You can have: (1) normal offset, short leg (head too small), (2) normal offset, long leg (head too large), (3) increased offset, normal leg (lateral cup position). **Goal**: Restore both offset and leg length to within 5mm of native or contralateral side. **Special considerations:** - **DDH**: High hip center, small canal, increased anteversion - may need structural graft, specialized implants - **AVN in young patient**: Consider resurfacing vs THA, templating for both - **Previous surgery**: Retained hardware, altered anatomy - plan hardware removal approach - **Leg length discrepancy**: Preoperative LLD may be longstanding, patient adapted - discuss postoperative expectations {/* SECTION 13: ALTERNATIVES TO THA */} **Before proceeding with THA in younger patients, consider alternatives:** **Refer to hip preservation surgeon** if: (1) Patient under 50 years, (2) Radiographic OA mild to moderate (joint space preserved), (3) Identifiable pathoanatomy (FAI, dysplasia), (4) Patient motivated for complex rehab. **Don't refer** if: Severe OA (Tonnis Grade 3), AVN with collapse, patient wants definitive solution (THA provides better pain relief than osteotomy in end-stage disease). **Hip resurfacing:** Once popular in young males, now **declining in use** due to: - Metal-on-metal bearing concerns (pseudotumor, metallosis, ARMD) - AOANJRR data shows higher revision rate than THA (especially in women) - Requires large femoral head (over 50mm), good bone quality - Contraindicated: Renal impairment, metal allergy, osteoporosis, cysts **Still considered** in: Young male athlete, very large femoral head, strong bone, patient counseled about risks {/* SECTION 13: MANAGEMENT ALGORITHM */} **THA Decision Pathway:** ### Initial Conservative Management **All patients** with hip OA should undergo trial of conservative treatment before THA: - **Education**: Natural history, activity modification, weight loss - **Physiotherapy**: Strengthen hip abductors, core, improve gait - **Analgesia**: Paracetamol, topical NSAIDs, oral NSAIDs (if tolerated) - **Adjuncts**: Walking aids (cane in opposite hand), heat/ice - **Intra-articular injection**: Corticosteroid (triamcinolone 40mg) - **Duration of relief**: Variable (50% get 3-6 months relief) - **PRP, hyaluronic acid**: Evidence limited, not PBS-funded in Australia - **Modify activities**: Avoid high-impact, aggravating movements If symptoms persist despite compliance with conservative measures → **Consider THA** Criteria for surgical referral: - Pain affecting sleep or ADLs - Limited walking distance (under 500m) - Patient-reported outcomes (Oxford Hip Score under 30/48) - Patient understands risks/benefits and motivated **6 months** is the generally accepted minimum duration of conservative treatment before THA. However, this is a **guideline**, not absolute rule. Exceptions: (1) Rapidly progressive painful AVN with collapse (may operate sooner), (2) Acute fracture in elderly (immediate surgery), (3) Patient tried conservative for years before presenting (don't need another 6 months). Use clinical judgment. ### Age-Based Decision Making ### Diagnosis-Specific Algorithms **Osteoarthritis:** - Conservative trial 6 months → If failed + symptoms severe → THA **AVN:** - Stage I-II (pre-collapse) → Core decompression, bisphosphonates, observation - Stage III-IV (collapse or secondary OA) → THA **Inflammatory Arthritis:** - Medical management with DMARDs first - If joint destruction despite medical Rx → THA (coordinate with rheumatology) **Post-Traumatic:** - Failed ORIF, malunion, AVN after fracture → THA when symptomatic **DDH:** - Young with symptoms, no OA → PAO - Established OA → THA with specialized planning These diagnosis-specific pathways guide optimal timing and treatment selection for THA candidacy. {/* SECTION 14: SURGICAL TECHNIQUE */} ### Surgical Approaches for THA | Approach | Internervous Plane | Key Features | |----------|-------------------|--------------| | Posterior (Moore/Southern) | Gluteus maximus (inferior gluteal) / Short external rotators (nerve to QF) | Most common, excellent femoral exposure | | Anterior (Smith-Petersen) | TFL (superior gluteal) / Sartorius (femoral) | Tissue-sparing, steep learning curve | | Direct Lateral (Hardinge) | Splits gluteus medius | Stable, abductor damage risk | ### Key Surgical Steps 1. **Positioning**: Lateral decubitus (posterior/lateral) or supine (anterior) 2. **Exposure**: Approach-specific dissection to hip joint 3. **Dislocation**: Flex, adduct, IR (posterior) or extend, ER (anterior) 4. **Neck osteotomy**: Planned level based on templating 5. **Acetabular prep**: Ream to subchondral bone, trial sizing 6. **Cup insertion**: Anteversion 15-20°, inclination 40-45° 7. **Femoral prep**: Broaching or reaming, trial sizing 8. **Stem insertion**: Press-fit or cemented 9. **Trial reduction**: Assess stability, leg length, offset 10. **Final implantation**: Head/liner assembly, closure The "safe zone" for cup positioning (Lewinnek): 40° ± 10° inclination, 15° ± 10° anteversion. Outside this range increases dislocation risk. ### Fixation Options AOANJRR data shows cemented fixation has lower revision rates in patients over 75 years. {/* SECTION 15: COMPLICATIONS */} **Complications of THA that patients must understand before consenting:** When consenting for THA, **must discuss**: (1) **Benefits** - pain relief (90-95% success), improved function, better quality of life. (2) **Risks** - infection (1%), dislocation (2-3%), DVT/PE (1-2%), nerve injury (1-2%), revision (5% at 15 years), leg length inequality (10%), ongoing pain (5-10%). (3) **Alternatives** - conservative, hip preservation, other arthroplasty options. (4) **Specific to patient** - age-related revision risk, comorbidity risks. {/* SECTION 17: POSTOPERATIVE CARE */} **Immediate postoperative management:** - **Pain control**: Multimodal analgesia (regional block, IV paracetamol, opioids as needed) - **DVT prophylaxis**: LMWH or apixaban (start 6-12 hours post-op) - **Mobilization**: Sit out of bed Day 0, walk with physio Day 1 - **Precautions**: Approach-specific (posterior = no flexion over 90°, adduction, IR) - Progressive mobilization with walking aids - Stair practice - Discharge planning (home setup, support) - Wound inspection - Wound review, suture/staple removal - Progress mobility, reduce walking aids - Continue DVT prophylaxis (6 weeks total) - Hip precautions education reinforcement - Clinical review, X-ray (AP pelvis) - Assess healing, component position, no subsidence - Progress to full weight-bearing, discard aids if able - Return to driving (if safe, right hip, off opioids) - Return to work (desk 6 weeks, manual 3 months) - Return to low-impact sports (swimming, cycling, golf) - Avoid high-impact (running, jumping sports) - Clinical examination, X-ray - PROMs (Oxford Hip Score, satisfaction) - Long-term surveillance plan (yearly first 5 years, then as needed) **Hip precautions** (approach-dependent): - **Posterior approach**: No flexion over 90°, no adduction past midline, no internal rotation (6-12 weeks) - **Anterior approach**: No extension, external rotation, or adduction (6 weeks) - **Lateral approach**: Minimal restrictions, avoid extreme abduction initially {/* SECTION 18: OUTCOMES AND PROGNOSIS */} **Expected outcomes of THA:** **Pain relief:** - 90-95% of patients report significant pain improvement - Most patients pain-free or minimal pain at rest and activity - Night pain typically completely resolved - Groin pain may persist in 5-10% (unexplained, may be from spine or soft tissues) **Functional improvement:** - Walking distance increases dramatically (unlimited in most patients) - Stair climbing normalized - ADLs (dressing, bathing, shoe tying) significantly easier - Return to work: 80-90% return to previous work level - Return to sport: Low-impact sports encouraged, high-impact discouraged **Patient satisfaction:** - 85-90% "very satisfied" with THA outcome - 5-10% "satisfied with reservations" (ongoing pain, stiffness, LLD) - Less than 5% "dissatisfied" (persistent pain, complications, unmet expectations) **Implant survival (AOANJRR data):** - **5 years**: 97% survival - **10 years**: 95% survival - **15 years**: 93-95% survival (modern implants) - **25 years**: 85-90% survival (projected) **Factors affecting outcome:** **Long-term surveillance:** - Annual clinical review first 5 years - X-rays at 1 year, then every 2-3 years - Monitor for: pain (loosening, infection), wear, osteolysis - AOANJRR tracks all Australian THAs for long-term outcomes {/* SECTION 19: EVIDENCE BASE */} {/* SECTION 20: VIVA SCENARIOS */} {/* SECTION 21: MCQ PRACTICE POINTS */} **Q: What are the three essential components of the indication for total hip arthroplasty?** A: **(1) Pain and functional disability** affecting quality of life, **(2) Radiographic evidence** of advanced osteoarthritis, **(3) Failed conservative treatment** for at least 6 months (physio, analgesia, weight loss, activity modification). All three must be present - radiographic severity alone is not an indication. **Q: What is the cumulative percent revision rate for primary THA at 15 years according to AOANJRR data?** A: **5%**, meaning **95% survivorship** at 15 years for modern THA implants. This is one of the most successful surgical procedures. Key additional AOANJRR findings: (1) Over 50,000 THAs performed annually in Australia, (2) Cemented femoral stems have lower revision rate in patients over 75 years, (3) Metal-on-metal hip resurfacing has higher revision rate than THA. **Q: What is the absolute contraindication to elective total hip arthroplasty?** A: **Active infection** (local or systemic) is an absolute contraindication. This includes active hip infection (previous septic arthritis), distant infection (UTI, dental abscess), or bacteremia. Infection must be eradicated (minimum 6 weeks antibiotics, inflammatory markers normal) before proceeding with elective THA. Risk of hematogenous seeding to prosthetic joint is too high. **Q: What is the lifetime revision burden for a 40-year-old patient undergoing THA?** A: **High** - studies show approximately **25% revision rate by 20 years** in patients under 40. This means the patient may need **2-3 revisions** over their lifetime. Main indications for revision: aseptic loosening (60%), instability (20%), infection (10%). Important to counsel young patients about this risk and consider hip preservation alternatives when possible. **Q: What HbA1c level is associated with significantly increased infection risk in THA, and what is the recommended management?** A: **HbA1c over 8%** is associated with **3-fold increased risk** of deep periprosthetic joint infection. **Management**: Postpone elective THA for 3 months of glycemic optimization with goal HbA1c under 8% (ideally under 7%). Refer to endocrinology, recheck HbA1c at 8-10 weeks. This is a **modifiable risk factor** - optimization reduces infection risk. **Q: At what stage of avascular necrosis is THA indicated, and why?** A: THA is indicated at **Stage III-IV** (Ficat classification): Stage III = subchondral collapse (crescent sign), Stage IV = secondary acetabular arthritis. **Why**: Once collapse occurs, hip preservation (core decompression) is no longer effective. THA provides reliable pain relief and restoration of function. Stage I-II (pre-collapse) can be managed with hip preservation techniques. {/* SECTION 22: AUSTRALIAN CONTEXT */} **Essential exam knowledge:** - Over 50,000 primary THAs annually in Australia - 95% survivorship at 15 years (modern implants) - Cemented femoral stems superior in patients over 75 years - Metal-on-metal resurfacing has higher revision rate than THA - Ceramic-on-polyethylene excellent long-term outcomes - Data guides evidence-based implant selection **Australian healthcare system:** - THA covered by Medicare (public system) with waiting times - Private health insurance covers elective THA with surgeon choice - PBS-funded medications: analgesia, DVT prophylaxis - Prostheses List regulates implant costs - MBS item numbers: 49318 (primary THA), 49319 (bilateral) **Key documentation requirements:** - **Informed consent**: Document discussion of risks (infection, dislocation, DVT, revision), benefits (pain relief, function), alternatives (conservative, other surgery) - **Failed conservative**: Document duration and compliance with non-operative treatment (minimum 6 months typically) - **Medical optimization**: HbA1c if diabetic, cardiac clearance if indicated, MRSA screening - **Preoperative planning**: Templating documented, leg length plan documented - **Complications disclosure**: Specific percentages (infection 1%, dislocation 2-3%, revision 5% at 15 years) - **Patient expectations**: Realistic goals discussed (pain relief yes, perfect hip no), activity restrictions - **Young patients**: Lifetime revision burden explicitly discussed and documented **Common litigation issues:** - Leg length discrepancy (most common cause of dissatisfaction) - document preoperative LLD and plan - Infection (ensure optimization, prophylaxis, technique) - Nerve palsy (avoid excessive lengthening, document neurovascular exam pre and post) - Wrong level (confirm hip using imaging in OR) In viva, demonstrate understanding of Australian context: (1) **Public system** - THA covered by Medicare, waiting times vary by state (6-12 months typical), urgent cases prioritized, (2) **Private system** - faster access, surgeon choice, implant choice, (3) **AOANJRR** - world-leading registry guides implant selection, quote data in exam, (4) **PBS** - medications covered (NSAIDs, analgesia, DVT prophylaxis), (5) **Prostheses List** - regulates implant costs, influences surgeon choice. {/* SECTION 23: EXAM CHEAT SHEET */}