import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Within acetabular shell**. Location: Liner-shell interface with locking mechanism. Protection: DRY, CLEAN shell; PLASTIC impactor only; SINGLE impaction; 360° inspection for complete seating; never use metal directly on ceramic. **On femoral stem trunnion**. Location: Head-taper (Morse taper) junction. Protection: DRY trunnion (wipe with sterile gauze); SINGLE firm impaction only; never tap multiple times (microcracks); use plastic or dedicated ceramic head impactor. **Femoral stem trunnion**. Location: Junction between femoral component and head. Protection: Inspect for scratches or damage; keep absolutely DRY; any taper damage causes fretting corrosion and head dissociation risk. **Posterior to hip joint**. Location: 1-2cm behind posterior acetabular rim, courses over short external rotators. Protection: Avoid over-retraction posteriorly; protect during capsulotomy; knee flexion reduces tension. **Anterior to hip joint**. Location: Femoral nerve, artery, vein in femoral triangle. Protection: Careful anterior retractor placement; avoid excessive anterior acetabular reaming; protect with anterior labrum if using DAA. ## Ceramic Evolution and Composition | Property | BIOLOX Delta (4th Gen) | Pure Alumina (3rd Gen) | |----------|------------------------|------------------------| | Composition | Alumina matrix + zirconia platelets + chromium oxide | 99.9% pure alumina (Al₂O₃) | | Fracture Rate | 0.02-0.05% | 0.1-0.2% | | Fracture Toughness | 6.5 MPa√m | 4.0 MPa√m | | Mechanism | Transformation toughening from zirconia | Brittle fracture | | Grain Size | Submicron (0.5μm) | Larger grains | | Head Sizes | 28mm, 32mm, 36mm available | Limited sizes | **Key Mechanism**: Zirconia platelets undergo phase transformation (tetragonal → monoclinic) when stressed, absorbing energy and stopping crack propagation ## Patient Selection for Ceramic-on-Ceramic **Ideal Candidates:** - Age less than 55-60 years - High activity level - Life expectancy more than 20 years - No metal allergy concerns - Adequate bone quality for uncemented fixation **Relative Contraindications:** - Severe hip dysplasia (difficult cup positioning) - High BMI (increased component stress) - Anxiety about squeaking **Absolute Contraindications:** - Previous ceramic fracture (any joint) - Inability to achieve optimal cup position - Cemented components (relative - less common) **Comparison with Other Bearings:** | Bearing | Wear Rate | Best For | Limitations | |---------|-----------|----------|-------------| | CoC | less than 0.01mm/yr | Young, active | Squeaking, fracture | | CoP (XLPE) | 0.01-0.05mm/yr | Most patients | Osteolysis long-term | | MoP | 0.1-0.2mm/yr | Older, lower demand | Higher wear | | MoM | Very low | AVOID | ALVAL, recall | ## Critical Acetabular Component Positioning **Lewinnek Safe Zone:** - Inclination: 40° ± 10° (range 30-50°) - Anteversion: 15° ± 10° (range 5-25°) **Why CoC is Less Forgiving:** - Hard-on-hard bearing = no deformation - Steep cups (more than 55°) = edge loading - Edge loading causes: - Stripe wear (visible wear pattern) - Squeaking (audible phenomenon) - Accelerated wear (paradoxically) - Potential ceramic fracture **Optimal Targets for CoC:** - Inclination: 35-45° (narrower than Lewinnek) - Anteversion: 10-20° - Combined anteversion: 25-35° (cup + stem) **Intraoperative Assessment:** - Visual estimation unreliable - Navigation improves accuracy - Fluoroscopy if available - Accept less than perfect → consider alternative bearing ## Understanding and Managing Squeaking **Incidence**: 1-10% of CoC THA **Causes (Multifactorial):** - Edge loading (cup malposition) - Stripe wear - Lubricant starvation - Component design - Patient factors (activity, weight) - Metal transfer (from revision instruments) **Clinical Assessment:** - When does it occur? (activity-related) - Associated pain? (suggests impingement) - Radiographic assessment of cup position - Metal ion levels if concerned **Management Algorithm:** 1. **Reassure**: Most squeaking is benign 2. **Activity modification**: Often resolves with time 3. **Wait**: Majority improve spontaneously 4. **Investigate** if: Pain, instability, progressive symptoms 5. **Revise** only if: Proven impingement, instability, infection **Key Message**: Squeaking is NOT automatic indication for revision ## Management of Catastrophic Ceramic Fracture **Incidence**: 0.02-0.05% with BIOLOX delta **Presentation:** - Acute onset pain after clicking sound - Immediate inability to weight bear - May have grinding sensation **Imaging:** - X-ray: May see fragmentation - CT scan: Better fragment assessment - Arthroscopy: NOT recommended (fragments everywhere) **Revision Surgery Principles:** 1. **Thorough debridement**: Remove ALL ceramic fragments 2. **Synovectomy**: Complete joint synovectomy required 3. **Pulse lavage**: Extensive irrigation (minimum 6L) 4. **Bearing choice**: NEVER ceramic-on-ceramic again 5. **Recommended**: Metal head on highly cross-linked polyethylene 6. **Rationale**: Even microscopic ceramic fragments cause catastrophic third-body wear if new ceramic bearing used **Outcomes:** - Higher complication rate than primary - Residual fragments cause accelerated wear - Consider constrainted liner if instability **Patient Position**: Per surgical approach preference - Lateral decubitus for posterior approach - Supine for direct anterior approach - Lateral for anterolateral approach **Surgical Approach**: Surgeon-preferred approach - ceramic bearing compatible with all standard approaches **Key Preparation Points:** - Confirm ceramic inventory availability (specific sizes) - Verify backup bearing option available - Preoperative templating for component sizing - Patient counseling about squeaking complete ### Step 1: BEARING SURFACE SELECTION BEARING SURFACE SELECTION: CERAMIC-ON-CERAMIC (CoC) indicated for young active patients where wear and longevity are priorities. Modern 4th generation ceramics (BIOLOX delta = alumina matrix composite with zirconia and chromium oxide) have superior fracture resistance. Lowest wear rates of all bearing couples (<0.01mm/year linear wear). Confirm appropriate patient selection criteria met. **Technical Tip**: EXAM KEY: BIOLOX DELTA is alumina matrix composite - NOT pure alumina. Contains zirconia platelets for transformation toughening. LOWEST WEAR of all bearings. Indicated in YOUNG, ACTIVE patients with good bone quality. - Wrong bearing selection for patient profile (age, activity, expectations) - Using older generation pure alumina ceramics (higher fracture risk) - Inadequate patient counseling about squeaking possibility ### Step 2: CONTRAINDICATION ASSESSMENT CONTRAINDICATIONS AND RISKS: Absolute: known ceramic fracture history (any joint). Relative: severe hip dysplasia (cup position difficult), high BMI (component stress), patient anxiety about squeaking. SQUEAKING occurs in 1-10% - usually benign but distressing. FRACTURE risk reduced with modern ceramics but still exists (0.02-0.05% with BIOLOX delta). **Technical Tip**: EXAM KEY: SQUEAKING is NOT failure - occurs 1-10%, multifactorial (edge loading, cup position, stripe wear). Reassure patients. FRACTURE rate now <0.05% with 4th gen ceramics. Previous ceramic fracture = ABSOLUTE contraindication. - Proceeding with contraindicated patient (prior ceramic fracture) - Inadequate preoperative discussion about complications - Not having backup bearing option available ### Step 3: SURGICAL APPROACH AND EXPOSURE SURGICAL APPROACH: Execute preferred approach (posterior, DAA, anterolateral). Excellent exposure essential for accurate cup positioning. CoC requires optimal visualization for precise component placement given less forgiving nature of hard-on-hard bearing. **Technical Tip**: Approach selection does not affect ceramic bearing outcomes. What matters is achieving OPTIMAL CUP POSITION. Poor exposure → poor position → edge loading → squeaking/wear/failure. - Inadequate exposure compromising cup positioning accuracy - Excessive soft tissue retraction causing nerve injury - Capsule damage affecting stability ### Step 4: ACETABULAR PREPARATION ACETABULAR PREPARATION: Standard sequential reaming technique. Remove all soft tissue from acetabular floor. Ream to bleeding subchondral bone. Critical to achieve optimal cup orientation - CoC is LESS FORGIVING of malposition than polyethylene. Target LEWINNEK SAFE ZONE: 40° ± 10° inclination, 15° ± 10° anteversion. For CoC, aim for narrower range: 35-45° inclination. **Technical Tip**: EXAM KEY: CoC LESS FORGIVING of cup malposition than metal-on-poly. Edge loading causes stripe wear and squeaking. STEEP CUPS (more than 55°) associated with higher failure. Target tighter tolerances than Lewinnek for hard-on-hard bearings. - Cup malposition outside target range (will cause edge loading) - Over-reaming compromising press-fit - Anterior column perforation with aggressive reaming ### Step 5: SHELL INSERTION AND POSITIONING SHELL INSERTION AND FIXATION: Standard press-fit technique with 1-2mm under-ream. Shell must be RIGIDLY FIXED before ceramic liner insertion. Any micromotion can cause liner dissociation. Supplemental screw fixation if any question of primary stability. Use alignment guides or navigation if available. **Technical Tip**: EXAM KEY: RIGID SHELL FIXATION mandatory before ceramic liner insertion. Micromotion → liner dissociation risk. Use supplemental screws if ANY doubt about fixation quality. Position first, fixation second with CoC. - Inadequate shell press-fit (leading to micromotion) - Malposition locked in before recognizing error - Over-impaction causing acetabular fracture ### Step 6: SHELL POSITION VERIFICATION SHELL POSITION VERIFICATION: Before liner insertion, confirm cup position within target range. Use intraoperative radiography if available. Assess inclination and anteversion. If outside optimal range for CoC, consider alternative bearing (polyethylene more forgiving). This is last chance to change bearing choice. **Technical Tip**: Once ceramic liner is impacted, bearing choice is committed. If cup position suboptimal (more than 50° inclination), strongly consider polyethylene liner instead. INTRAOPERATIVE DECISION POINT. - Proceeding with ceramic liner despite suboptimal cup position - Missing opportunity to convert to polyethylene - Inadequate position assessment before commitment ### Step 7: SHELL PREPARATION FOR LINER SHELL PREPARATION FOR LINER: Shell must be absolutely DRY and FREE OF DEBRIS before ceramic liner insertion. Any particle (bone, blood, cement, debris) can chip ceramic during impaction. Use sterile gauze to dry shell completely. Inspect for any loose material. No saline rinse (leave wet surface). **Technical Tip**: EXAM KEY: DRY, CLEAN shell is MANDATORY. Any debris causes ceramic chipping → third-body wear → accelerated failure. Wipe with DRY sterile gauze, not saline. Inspect 360° before liner insertion. - Debris in shell causing ceramic chip during impaction - Wet shell surface interfering with liner seating - Blood/soft tissue in shell-liner interface ### Step 8: CERAMIC LINER INSERTION - CRITICAL STEP CERAMIC LINER INSERTION: Check liner orientation for locking mechanism alignment with shell. Use PLASTIC IMPACTOR (never metal directly on ceramic). Position liner in shell with correct orientation. Apply STEADY FIRM PRESSURE - listen for click confirming seating. SINGLE IMPACTION only - repeated impaction can chip liner. No adjustments once impacted. **Technical Tip**: EXAM KEY: PLASTIC IMPACTOR only on ceramic. SINGLE IMPACTION with firm steady pressure. Never hammer directly on ceramic with metal. Multiple impaction attempts create microcracks and chips. - Using metal impactor directly on ceramic liner - Multiple impaction attempts causing chips/cracks - Incorrect liner orientation (locking mechanism misaligned) - Incomplete seating from inadequate impaction force ### Step 9: LINER SEATING VERIFICATION VERIFY LINER SEATING: After insertion, INSPECT 360° for complete seating. Run finger around liner-shell junction - any gap indicates incomplete seating. Check locking mechanism engaged (audible click, visual confirmation). Confirm no chips or cracks visible on liner face or edge. Any concern → remove and re-assess. **Technical Tip**: EXAM KEY: 360° INSPECTION for complete seating is MANDATORY. Any visible gap = incomplete seating = dissociation risk. Check locking mechanism ENGAGED. Undetected incomplete seating → early failure. - Missing incomplete liner seating (will dissociate) - Undetected chip or crack (will propagate) - Locking mechanism not engaged (liner will rotate/dissociate) ### Step 10: FEMORAL PREPARATION FEMORAL PREPARATION: Standard technique for chosen stem (cementless or cemented). Sequential broaching to appropriate size. Prepare for trial reduction. Ceramic head sizing per templating - confirm available inventory. **Technical Tip**: Femoral preparation is standard technique. The critical ceramic-specific steps are in head placement. Ensure trunnion (Morse taper) remains undamaged during broaching and trialing. - Damaging femoral stem trunnion during preparation - Inadequate femoral stem fixation - Femoral fracture from aggressive broaching ### Step 11: TRIAL REDUCTION TRIAL REDUCTION: Insert trial head on stem trunnion. Reduce hip and assess stability, leg length, offset. Standard testing in flexion, extension, rotation. AVOID extreme positions that cause edge loading during trials. Confirm appropriate head size and neck length. **Technical Tip**: Trial reduction with trial head is standard. This assesses stability and leg length before committing to ceramic head. Avoid excessive testing in positions that stress ceramic edge (combined flexion/IR/adduction). - Trunnion damage from trial head placement/removal - Missing instability before final head placement - Edge loading positions during aggressive stability testing ### Step 12: TRUNNION PREPARATION FOR CERAMIC HEAD TRUNNION PREPARATION: After removing trial head, inspect trunnion (Morse taper) carefully. Must be PRISTINE - any scratches or damage cause fretting corrosion and head dissociation risk. Taper must be absolutely DRY - wipe with sterile dry gauze. No saline. No blood. Completely dry surface essential for ceramic head seating. **Technical Tip**: EXAM KEY: MORSE TAPER must be CLEAN, DRY, UNDAMAGED. Any scratches cause fretting corrosion → head dissociation. Inspect trunnion under direct vision. Wipe dry with sterile gauze - no wet surfaces. - Damaged trunnion causing fretting corrosion and dissociation - Wet taper causing poor ceramic head seating - Blood/debris on taper interface ### Step 13: CERAMIC HEAD IMPACTION CERAMIC HEAD IMPACTION: Place ceramic head on dry trunnion. Confirm correct orientation. Single FIRM impaction using plastic or dedicated ceramic head impactor. Do NOT tap head multiple times - can create microcracks that propagate to fracture. Head should seat with audible click. Never use metal directly on ceramic head. **Technical Tip**: EXAM KEY: DRY TAPER. SINGLE FIRM IMPACTION. Multiple taps create microcracks → delayed fracture. Never use metal mallet directly on ceramic. Audible click confirms seating. - Wet taper causing poor seating → dissociation - Multiple impactions creating microcracks → fracture - Metal impactor damaging ceramic head - Incomplete seating from inadequate impaction force ### Step 14: REDUCTION AND STABILITY TESTING REDUCTION AND STABILITY: Reduce hip. Standard stability testing in flexion, extension, internal/external rotation, adduction. AVOID EDGE LOADING positions during testing - extreme flexion with internal rotation and adduction stresses ceramic edge. Document ROM achieved. Confirm stable reduction in functional positions. **Technical Tip**: EXAM KEY: Avoid extreme positions that cause EDGE LOADING during stability testing. Combined flexion/IR/adduction stresses ceramic bearing edge. Test stability but respect ceramic limitations. - Edge loading causing ceramic damage during testing - Dislocation during aggressive stability testing - Missing subtle instability before closure ### Step 15: CLOSURE AND POST-OPERATIVE CONSIDERATIONS CLOSURE AND POST-OPERATIVE CARE: Standard layered closure. Standard THA rehabilitation protocol. No specific activity restrictions beyond standard hip precautions. Counsel patient about SQUEAKING - occurs 1-10%, usually benign. Most squeaking improves over time. Long-term surveillance with standard follow-up schedule. **Technical Tip**: EXAM KEY: COUNSEL about squeaking preoperatively - sets expectations. Squeaking is NOT indication for revision unless symptomatic impingement proven. Excellent long-term wear rates justify ceramic bearing in appropriate patients. - Inadequate patient education about squeaking - Patient anxiety leading to unnecessary revision request - Missing postoperative complications (infection, dislocation) **Immediate Post-operative:** - Standard THA recovery protocol - Weight bearing as tolerated (unless bone quality concerns) - VTE prophylaxis per institutional protocol - Standard hip precautions per surgical approach **Rehabilitation:** - No specific restrictions beyond standard THA precautions - Progressive ROM and strengthening - Gait training with appropriate assistive device - Standard return to activity timeline **Follow-up:** - 2 weeks: Wound check - 6 weeks: Clinical and radiographic review - 3 months: Function assessment - 1 year: Standard annual review - Annual or biennial long-term surveillance **Patient Education:** - Squeaking may occur (1-10%) - NOT failure - Report acute onset pain or clicking (may indicate fracture) - Excellent long-term wear expected - Standard activity guidelines **References:** 1. D'Antonio JA, et al. Long-term experience with ceramic-on-ceramic THA. J Bone Joint Surg Am. 2012;94(18):1703-1711. 2. Hamilton WG, et al. Midterm prospective results of ceramic-on-ceramic articulation. J Arthroplasty. 2010;25(6 Suppl):126-131. 3. Chevillotte C, et al. Nine years follow-up of 100 ceramic-on-ceramic total hip arthroplasty. Int Orthop. 2011;35(11):1599-1604. 4. Traina F, et al. Long-term results of a cementless ceramic-on-ceramic THA. J Bone Joint Surg Am. 2013;95(12):1052-1058. 5. Jeffers JR, Walter WL. Ceramic-on-ceramic bearings in hip arthroplasty: state of the art and the future. J Bone Joint Surg Br. 2012;94(6):735-745. 6. Lusty PJ, et al. Fourth generation ceramic-on-ceramic THA. Bone Joint J. 2007;89-B(12):1630-1635. 7. Walter WL, et al. Squeaking in ceramic-on-ceramic hips: the importance of acetabular component orientation. J Arthroplasty. 2007;22(4):496-503. 8. Capello WN, et al. Ceramic-on-ceramic total hip arthroplasty: update. J Arthroplasty. 2008;23(7 Suppl):39-43. 9. Esposito CI, et al. What is the trouble with trunnions? Clin Orthop Relat Res. 2014;472(12):3652-3658. 10. Hannouche D, et al. Thirty years of experience with alumina-on-alumina bearings in total hip arthroplasty. Int Orthop. 2011;35(2):207-213.

Ceramic-on-Ceramic THA

Ceramic-on-Ceramic THA