Introduction Biomechanics of total hip arthroplasty depend on prosthesis design bearing surface and lubrication characteristics fixation method Designs include femoral component cemented press-fit (uncemented) tapered stems extensively porous coated stems modular stems acetabular components cemented polyethylene metal press-fit (uncemented) metal bearing surfaces polyethylene metal ceramic History 1891 Dr. Gluck performs first reported attempt at a hip replacement with ivory used to replace the femoral head 1940 Austin Moore performs first metallic hip replacement surgery (hemiarthroplasty) with a proximal femoral replacement bolted to the femur 1952 Austin Moore prosthesis developed 1960s Sir John Charnley introduces concept of low friction arthroplasty concept termed "low friction" as a small femoral head was used to reduce wear components metal femoral stem polyethylene acetabular component acrylic bone cement Press-fit Femoral Stems Overview rely on biologic fixation compression hoop stresses provide initial stability Types tapered stems most are proximally coated stems that taper distally examples Tri-Lock (DePuy) M/L Taper (Zimmer) extensively coated stems porous coating extends into the diaphysis for distal engagement examples AML (DePuy) VerSys Full Coat (Zimmer) modular stems distal stem and proximal body can be "mixed-and-matched" examples S-ROM (DePuy) ZMR (Zimmer) Unique complications intraoperative fracture more likely in press-fit through lateral approach typically due to underreaming loosening high loosening rate when used in irradiated bone (due to lack of ingrowth) junctional corrosion seen in modular components (including cemented modular components) Cemented Femoral Stems Overview rely on cement fixation cement is a grout that provides initial and long-term stability limited remodeling potential preferred for irradiated bone due to the bone's limited ability for ingrowth composition cobalt-chrome or stainless steel most common reduce cement stresses titanium prone to micromotion and debonding less stiff than cobalt-chrome or stainless steel stems cemented titanium stems leads to crevice corrosion (use of cemented titanium alloy stems is no longer recommended) Unique complications stem breakage cemented stems are smaller than press-fit stems and unable to tolerate as much cantilever bending may occur in cementless stems as well Bearing Surfaces Metal-on-polyethylene metal (cobalt-chrome) femoral head on polyethylene acetabular liner benefits longest track record of bearing surfaces lowest cost most modularity disadvantages higher wear and osteolysis rates compared to metal-on-metal and ceramics smaller head (compared to metal-on-metal) leads to higher risk of impingement Metal-on-metal benefits better wear properties than metal-on-polyethylene lower linear wear rate debris particles much smaller (but more numerous) than those of metal-on-poly overall smaller volume of particles larger head allows for increased ROM before impingement disadvantages more expensive than metal-on-polyethylene increased metal ions in serum and urine (5-10x normal) serum metal ion concentration highest at 12-24 months correlates with the initial "wear in" or "run-in" phase of increased particle generation, but then followed by a "steady state" phase of decreased particle generation no proven cancer link may form pseudotumors hypersensitivity (Type IV delayed type hypersensitvity) mediated by T-cells metals sensitize and activate T-cells (nickel > cobalt and chromium) however, most participating cells are macrophages (only 5% are lymphocytes) antigen-activated T-cells secrete cytokines that activate macrophages activated macrophages have increased ability to present class II MHC and IL-2, leads to increased T-cell activation the cycle continues contraindications pregnant women renal disease metal hypersensitivity due to metal ions Ceramic on Ceramic benefits best wear properties of all bearing surfaces lowest coefficient of friction of all bearing surfaces inert particles no concern for cancer risk disadvantages more expensive than metal-on-polyethylene worst mechanical properties (alumina is brittle, low fracture toughness) small 28mm heads only exist in zirconia because of alumina's inferior mechanical properties squeaking increased risk with edge loading impingement and acetabular malposition third-body wear loss of fluid film lubrication thin, flexible (titanium) stems less modularity with fewer neck length options stripe wear caused by contact between the femoral head and rim of the cup during partial subluxation results in a crescent shaped line on the femoral head Ceramic on polyethylene benefits standard of care alumina ceramic heads results in less polyethylene wear than metal-on-polyethylene (MoP) bearings disadvantages zirconia undergoes tetragonal to monoclinic phase transformation with time increased with prolonged in vivo implantation >8yr pressure temperature has lower heat conductivity than alumina (joint temperature can reach 99oC for zirconia, and 50oC for alumina) Titanium on Polyethylene not recommended due to high wear rates disadvantages
QUESTIONS 1 of 19 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ12.159) What surgeon is credited for designing the prosthesis seen in Figure A? QID: 4519 FIGURES: A Type & Select Correct Answer 1 John Charnley 16% (823/5200) 2 San Baw 0% (16/5200) 3 Sir Harry Platt 2% (89/5200) 4 Austin T. Moore 81% (4194/5200) 5 Charles Frederick Thackray 1% (43/5200) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE10HK.67) A patient with a severe nickel allergy and degenerative joint disease of the hip would be best served by which of the following prosthetic options? QID: 7055 Type & Select Correct Answer 1 Cemented titanium stem, ceramic (alumina) head, and press-fit titanium cup 10% (122/1205) 2 Cemented cobalt-chrome stem, ceramic (alumina) head, and press-fit cobalt-chrome cup 8% (96/1205) 3 Press-fit titanium stem, cobalt-chrome head, and press-fit titanium cup 5% (55/1205) 4 Press-fit titanium stem, titanium head, and press-fit titanium cup 8% (91/1205) 5 Press-fit titanium stem, ceramic (alumina) head, and cementless titanium cup 69% (837/1205) L 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ09.78) An 80-year-old man has a Charnley all-polyethylene acetabular shell shown in Figure A. When defining failure as revision for any reason, what is the failure rate at 35 years for this type of prosthesis? QID: 2891 FIGURES: A Type & Select Correct Answer 1 Less than 10% 10% (374/3582) 2 20% to 30% 53% (1899/3582) 3 40% to 50% 11% (382/3582) 4 50% to 75% 11% (409/3582) 5 Greater than 75% 14% (501/3582) L 3 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07HK.70) With the increasing availability of total hip arthroplasty (THA) to younger patients with hip osteoarthritis, there has been increased use of alternative bearing surfaces. Compared to a ceramic-on-ceramic articulation, which of the following is a specific advantage of a metal-on-metal bearing surface? QID: 6030 Type & Select Correct Answer 1 Increased wettability 4% (39/987) 2 Increased hardness 11% (112/987) 3 Increased fracture toughness 61% (604/987) 4 Decreased surface roughness 4% (44/987) 5 Lower coefficient of friction 18% (182/987) L 3 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07HK.55) Based on the type of articulation shown in Figure 32, wear is not affected by which of the following factors? QID: 6015 FIGURES: A Type & Select Correct Answer 1 Radial mismatch of the femoral head to the acetabular component 8% (59/726) 2 Sphericity of the bearings 9% (63/726) 3 Surface finish of the articulation 6% (42/726) 4 Carbon content of the metal-on-metal bearing 20% (142/726) 5 Head-to-neck ratio 58% (418/726) L 3 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 Review Tested Concept Review Full Topic This is an AAOS Self Assessment Exam (SAE) question. Orthobullets was not involved in the editorial process and does not have the ability to alter the question. If you prefer to hide SAE questions, simply turn them off in your Learning Goals. (SAE07HK.12) Compared to metal-on-polyethylene total hip bearing surfaces, the debris particles generated by metal-on-metal articulations are QID: 5972 Type & Select Correct Answer 1 larger and less numerous. 6% (71/1182) 2 larger and more numerous. 10% (119/1182) 3 smaller and less numerous. 10% (118/1182) 4 smaller and more numerous. 74% (869/1182) 5 not detectable. 0% (3/1182) L 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 Review Tested Concept Review Full Topic (SBQ07HK.3) A 56-year-old gentleman presents to your office one year after undergoing total hip arthroplasty with the implant seen in Figure A. He is concerned about the potential complications given the recent media attention his implant has received. He is currently asymptomatic. Which of the following statements is accurate regarding his prosthesis and future care? QID: 1588 FIGURES: A Type & Select Correct Answer 1 He should have bi-annual LFTs measured, as metal ions are metabolized by the liver. 21% (744/3560) 2 His risk of developing cancer is dramatically increased. 1% (51/3560) 3 There is no correlation between activity level and serum levels of metal ions. 70% (2485/3560) 4 His prosthesis design is safe in women of child-bearing age as the ions cannot be transmitted via pregnancy. 4% (132/3560) 5 His prosthesis design puts him at an increased risk for dislocation. 4% (128/3560) L 1 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Review Tested Concept Review Full Topic (OBQ04.45) All of the following are true for a patient who underwent a metal-on-metal total hip arthroplasty (THA) EXCEPT? QID: 106 Type & Select Correct Answer 1 they will have production of ionically charged wear particles 3% (117/3883) 2 there is a higher cancer risk than with metal-on-polyethylene THA 76% (2968/3883) 3 they will have elevated levels of cobalt and chromium in the serum 3% (114/3883) 4 they will have elevated levels of cobalt and chromium in the urine 7% (270/3883) 5 there is a higher frictional torque than with ceramic on ceramic THA 10% (401/3883) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic
All Videos (6) Podcasts (2) Login to View Community Videos Login to View Community Videos Orthopaedic Summit Evolving Techniques 2021 Evolving Technique Update: Collared Cementless Stems: Bill Harris Taught Us Years Ago, Enhanced Stability Without Cement - Hari Parvataneni, MD Recon - THA Prosthesis Design 12/22/2022 34 views 5.0 (1) Login to View Community Videos Login to View Community Videos Orthopaedic Summit Evolving Techniques 2021 Evolving Technique Update: Not Every Dual Mobility Is The Same: How I Chose a DM Implant - Ran Schwarzkopf, MD, MSc Ran Schwarzkopf Recon - THA Prosthesis Design 12/22/2022 54 views 4.0 (3) ICJR 8th Annual Revision Hip & Knee Course Current Algorithm for MOM Bearings and Taper Corrosion - R. Michael Meneghini, MD Robert Meneghini Recon - THA Prosthesis Design 5/16/2022 508 views 4.8 (4) Recon ⎜ THA Prosthesis Design (ft. Dr. Harry Rubash) Team Orthobullets (AF) Recon - THA Prosthesis Design Listen Now 13:45 min 10/18/2019 214 plays 5.0 (1) Recon⎪THA Prosthesis Design Recon - THA Prosthesis Design Listen Now 29:16 min 5/12/2020 859 plays 5.0 (3) See More See Less