Introduction Designs include unconstrained posterior-cruciate retaining (CR) posterior-cruciate substituting (PS) constrained nonhinged hinged fixed versus mobile bearing History 19th century interposition of soft tissues for reconstruction of articular surfaces 1950s Walldius designs first hinged knee replacement 1958 MacIntosh and McKeever introduce acrylic tibial plateau prosthesis to correct deformity 1960s Gunston introduces first cemented surface arthroplasty of knee joint 1970 Guepar develops a new hinged prosthesis based on design by Walldius that increases motion and decreases bone loss ~1973 "total condylar prosthesis" is introduced which is first to resurface all three compartments (PCL sacrificing) Concepts in Prosthetic Design Femoral rollback definition the posterior translation the femur with progressive flexion importance improves quadriceps function and range of knee flexion by preventing posterior impingement during deep flexion biomechanics rollback in the native knee is controlled by the ACL and PCL design implications both PCL retaining and PCL substituting designs allow for femoral rollback PCL retaining native PCL promotes posterior displacement of femoral condyles similar to a native knee PCL substituting tibial post contacts the femoral cam causing posterior displacement of the femur Constraint definition the ability of a prosthesis to provide varus-valgus and flexion-extension stability in the face of ligamentous laxity or bone loss importance in the setting of ligamentous laxity or severe bone loss, standard cruciate-retaining or posterior-stabilized implants may not provide stability design implications in order of least constrained to most constrained cruciate-retaining posterior-stabilized (cruciate-substituting) varus-valgus constrained (non-hinged) rotating-hinge Modularity definition the ability to augment a standard prosthesis to balance soft tissues and/or restore bone loss options include metal tibial baseplate with modular polyethylene insert more expensive than all-polyethylene tibial component has an equivalent rate of aseptic loosening compared with all-polyethylene tibia component metal augmentation for bone loss modular femoral and tibial stems advantages ability to customize implant intraoperatively disadvantages increased rates of osteolysis in modular components backside polyethylene wear micromotion between tibial baseplate and undersurface of polyethylene insert that occurs during loading Cruciate-Retaining (CR) Design Design minimally constrained prosthesis that depends on an intact PCL to provide stability in flexion Indications arthritis with minimal bone loss, minimal soft tissue laxity, and an intact PCL varus deformity < 10 degrees valgus deformity < 15 degrees Radiographs radiographs won't show box in the central portion of the femoral component as PS knees have (see PS knee radiographs) Advantages avoids tibial post-cam impingement/dislocation that may occur in PS knees more closely resembles normal knee kinematics (controversial) less distal femur needs to be cut than in a PS knee improved proprioception with preservation of native PCL newer poly-options can allow for PCL substitution via anterior-stabilized or ultra-congruent shapes in cases of PCL insufficiency without loss of functional results Disadvantages tight PCL may cause accelerated polyethylene wear loose or ruptured PCL may lead to flexion instability and subluxation Posterior Stabilized (PS) Design Design slightly more constrained prosthesis that requires sacrifice of PCL resection of PCL increases the flexion gap in relationship to extension gap so posterior must be matched to avoid flexion-extension mismatch femoral component contains a cam that engages the tibial polyethylene post during flexion polyethylene inserts are more congruent, or deeply "dished" Indications previous patellectomy reduces risk of potential anteroposterior instability in setting of a weak extensor mechanism inflammatory arthritis inflammatory arthritis may lead to late PCL rupture deficient or absent PCL Radiographs lateral radiograph will show the outline of the cam, or box, in the femoral component Advantages easier to balance a knee with absent PCL arguably more range of motion easier surgical exposure Disadvantages cam jump mechanism with loose flexion gap, or in hyperextension, the cam can rotate over the post and dislocate treatment initial closed reduction by performing an anterior drawer maneuver final revision to address loose flexion gap tibial post polyethylene wear patellar "clunk" syndrome mechanism scar tissue gets caught in box as knee moves into extension treatment arthroscopic versus open resection of scar tissue additional bone is cut from distal femur to balance extension gap Constrained Nonhinged Design Design constrained prosthesis without axle connecting tibial and femoral components (nonhinged) large tibial post and deep femoral box provide varus/valgus stability rotational stability Indications LCL attenuation or deficiency MCL attenuation or deficiency flexion gap laxity moderate bone loss in the setting of neuropathic arthropathy Radiographs Advantages prosthesis allows stability in the face of soft tissue (ligamentous) or bony deficiency Disadvantages more femoral bone resection necessary to accommodate large box aseptic loosening as a result of increased constraint Constrained Hinged Design Design most constrained prosthesis with linked femoral and tibial components (hinged) tibial bearing rotates around a yoke on the tibial platform (rotating hinge) decreases overall level of constraint Indications global ligamentous deficiency hyperextension instability seen in polio or tumor resections resection for tumor massive bone loss in the setting of a neuropathic joint Radiographs Advantages prosthesis allows stability in the face of soft tissue (ligamentous) or bony deficiency Disadvantages aseptic loosening as a result of increased constraint large amount of bone resection required Mobile Bearing Design Design minimally constrained prosthesis where the polyethylene can rotate on the tibial baseplate PCL is removed at time of surgery Indications young, active patients (relative indication) Advantages theoretically reduces polyethylene wear increased contact area reduces pressures placed on polyethylene (pressure=force/area) Disadvantages bearing spin-out mechanism occurs as a result of a loose flexion gap tibia rotates behind femur treatment initial closed reduction final revision to address loose flexion gap All-polyethylene base plates Design tibial plate is a solid block of polyethylene as opposed to a metal tray with a poly insert. Indications no clear indications Advantages less expensive decreased rates of osteolysis Disadvantages lose modular flexibility Outcomes studies show equivalent functional outcomes with decreased cost Highly Congruent Liners Design medial compartment concavity allows lateral compartment to translate between flexion and extension this creates a medial pivot Indications no clear indications Advantages may better create native knee kinematics Outcomes studies show equivalent outcomes and survivorship in short and mid-term studies
Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. TKA - Parapatellar Approach Derek Bernstein Stephen Incavo Recon - High Tibial Osteotomy Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. TKA - Varus Knee with Anterior Referencing and Gap Balancing Technique Derek Bernstein Stephen Incavo Recon - TKA Axial Alignment Technique Guide Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC. TKA with Computer Navigation & Sensor-Guided Assessment for Soft Tissue Balancing - Dr. William Gall William Gallivan Recon - TKA Axial Alignment
QUESTIONS 1 of 27 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 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 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ12.92) Which of the following types of prosthetic designs, seen in figures A-E, has been shown to have a high rate of loosening secondary to overconstraint? Review Topic | Tested Concept QID: 4452 FIGURES: A B C D E Type & Select Correct Answer 1 Figure A 1% (64/4669) 2 Figure B 4% (194/4669) 3 Figure C 86% (4008/4669) 4 Figure D 5% (236/4669) 5 Figure E 3% (144/4669) L 2 Question Complexity B Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ11.126) A patient undergoes the procedure depicted in Figures A and B with standard components (non-gender specific). Which of the following outcomes most appropriately describes the difference in females compared to males for this procedure? Review Topic | Tested Concept QID: 3549 FIGURES: A B Type & Select Correct Answer 1 Greater implant survivorship 65% (2560/3909) 2 Decreased WOMAC scores 15% (580/3909) 3 Increased rate of extensor mechanism rupture 4% (148/3909) 4 Increased postoperative pain 13% (499/3909) 5 Increased component osteoloysis 3% (105/3909) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ10.201) A posterior cruciate retaining total knee arthroplasty is contraindicated in all of the following patients EXCEPT? Review Topic | Tested Concept QID: 3294 Type & Select Correct Answer 1 52-year-old female with severe rheumatoid arthritis of the knee 4% (117/3160) 2 73-year-old male with post-traumatic arthritis of the knee and prior patellectomy 9% (279/3160) 3 67-year-old male with degenerative arthritis and 10 degree valgus deformity of the knee 73% (2317/3160) 4 55-year-old male with post-traumatic arthritis of the knee 20 years after bicruciate ligament ruptures 8% (249/3160) 5 63-year-old female with a chronic history of steroid treatment of systemic lupus erythematosus and an arthritic knee 6% (185/3160) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway 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.19) Increasing articular conformity of the tibial polyethylene insert of a fixed-bearing total knee arthroplasty (TKA) prosthesis will have which of the following biomechanical effects? Review Topic | Tested Concept QID: 5979 Type & Select Correct Answer 1 Decreased contact stress within the polyethylene 57% (144/251) 2 Decreased risk of patellofemoral instability 3% (7/251) 3 Decreased risk of mechanical loosening 9% (22/251) 4 Increased risk of subsurface polyethylene cracking 16% (41/251) 5 Increased femoral rollback during flexion 14% (36/251) L 3 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK You have 100% on this question. Just skip this one for now. Take This Question Anyway 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.63) A patient with a documented allergy to nickel requires a total knee arthroplasty. Which of the following prostheses is most likely to provide long-term success in this individual? Review Topic | Tested Concept QID: 6023 Type & Select Correct Answer 1 All-polyethylene tibial component and pure titanium femoral component 27% (118/434) 2 All-polyethylene tibial component and cobalt-chromium alloy femoral component 6% (26/434) 3 Cobalt-chromium alloy tibial component and cobalt-chromium alloy femoral component 10% (44/434) 4 Modular titanium tibial component and pure titanium femoral component 20% (86/434) 5 Modular titanium tibial component and oxidized zirconium femoral component 36% (157/434) L 4 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 5 You have 100% on this question. Just skip this one for now. Take This Question Anyway 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.39) When performing knee arthroplasty, which of the following procedures provides the most consistent fixation for the tibial component? Review Topic | Tested Concept QID: 5999 Type & Select Correct Answer 1 Cementless fixation of the tibial component 2% (7/308) 2 Augmenting cementless fixation of the tibial component with pegs or screws 1% (2/308) 3 Cementing the metaphyseal portion and press fitting the keel of the tibial component 15% (46/308) 4 Cementing the metaphyseal and keel portions of the tibial component 79% (243/308) 5 Cemented fixation of the tibial component with screws 2% (7/308) L 2 Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 You have 100% on this question. Just skip this one for now. Take This Question Anyway 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.54) When comparing mobile-bearing total knee arthroplasty (TKA) to fixed-bearing total condylar arthroplasty, the mobile-bearing procedure provides Review Topic | Tested Concept QID: 6014 Type & Select Correct Answer 1 no improvement in survivorship. 62% (127/205) 2 approximately 15 degrees greater flexion. 12% (24/205) 3 appreciable reduction in wear rates. 22% (45/205) 4 a faster recovery profile. 3% (6/205) 5 better quadriceps strength. 1% (2/205) N/A Question Complexity E Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ07.28) Figure A displays the preoperative radiographs of a 67-year-old obese, diabetic woman undergoing total knee arthroplasty. Following the bone resections, a PCL-substituting trial implant is placed. At full extension, 30 degrees of flexion, and 90 degrees of flexion, the knee is found to be tight laterally and loose medially. Sequential releases are made until the IT band, popliteus, and LCL have all been released, and a larger polyethylene trial is placed, but the knee continues to demonstrate medial laxity and lateral tightness. Which of the following should be done to achieve a successful outcome? Review Topic | Tested Concept QID: 689 FIGURES: A Type & Select Correct Answer 1 Surgical release of the lateral retinaculum 4% (158/4025) 2 Surgical release of the lateral retinaculum and reconstruction of the medial patellofemoral ligament 3% (101/4025) 3 Imbrication of the MCL and augmentation with allograft 5% (185/4025) 4 Convert to a constrained TKA design 75% (3037/4025) 5 Recut the tibia in valgus to improve balance 13% (525/4025) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ07HK.1) A 57-year-old man complains of knee pain that is exacerbated with weight bearing and ambulation. He underwent surgery on his knee 10 years ago following a motor vehicle collision. On physical exam he has medial and lateral joint line tenderness and no instability. Radiographs are provided in figures A and B. Conservative therapy with NSAID's and viscosupplementation is initiated. If he continues to develop further degenerative changes and needs arthroplasty what type of implant should be utilized? Review Topic | Tested Concept QID: 1586 FIGURES: A B Type & Select Correct Answer 1 Unicompartmental mobile bearing knee arthroplasty 6% (116/2050) 2 Posterior cruciate retaining total knee arthroplasty 24% (496/2050) 3 Posterior stabilized total knee arthroplasty 64% (1302/2050) 4 Constrained nonhinged total knee arthroplasty 3% (59/2050) 5 Constrained hinged total knee arthroplasty 3% (70/2050) L 2 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ07.46) In total knee arthroplasty, what would be a difference with use of the tibial component shown in Figure A compared to Figure B? Review Topic | Tested Concept QID: 707 FIGURES: A B Type & Select Correct Answer 1 Increased ductility of the polyethylene 2% (33/1353) 2 Increased wear on the articular side of the polyethylene 5% (68/1353) 3 Less wear on the articular side of the polyethylene 7% (95/1353) 4 More wear at the backside of the polyethylene 68% (926/1353) 5 Less wear at the backside of the polyethylene 17% (224/1353) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 4 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ07HK.6) The medial and lateral joint surfaces have different tibiofemoral geometry. How does this affect the kinematics of normal knee movement from full extension into flexion? Review Topic | Tested Concept QID: 1591 Type & Select Correct Answer 1 Tibia will externally rotate 25% (1090/4279) 2 Distal femur will pivot about a medial axis of the knee 53% (2249/4279) 3 Distal femur will translate anteriorly on the tibia 8% (354/4279) 4 Distal femur will pivot about a lateral axis of the knee 12% (514/4279) 5 No effect 1% (47/4279) L 4 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 You have 100% on this question. Just skip this one for now. Take This Question Anyway (SBQ07HK.7) A 55-year-old female with a long history of diabetes mellitus presents for evaluation of chronic knee pain. A current radiograph is shown in Figure A. Which of the following knee prostheses, shown in Figures B through E, would be most appropriate in the initial treatment of this patient? Review Topic | Tested Concept QID: 1592 FIGURES: A B C D E F Type & Select Correct Answer 1 Figure B 54% (897/1652) 2 Figure C 13% (209/1652) 3 Figure D 11% (182/1652) 4 Figure E 21% (347/1652) 5 Figure F 1% (9/1652) L 3 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ05.265) Figure A demonstrates a total knee prosthesis design. Which of the following motions is constrained in this particular design: Review Topic | Tested Concept QID: 1151 FIGURES: A Type & Select Correct Answer 1 Complete anterior-posterior translation constraint only 10% (239/2468) 2 Partial varus-valgus angulation constraint only 14% (348/2468) 3 Partial varus-valgus angulation and partial internal-external rotation constraint 53% (1307/2468) 4 Complete internal-external rotation constraint only 1% (33/2468) 5 Complete varus-valgus angulation and anterior-posterior translation constraint 22% (533/2468) L 4 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 3 You have 100% on this question. Just skip this one for now. Take This Question Anyway (OBQ04.143) A 45-year-old woman is scheduled to undergo a TKA. Which of the following implant designs theoretically reduces poylethylene wear and reduces bone-implant-interface stress? Review Topic | Tested Concept QID: 1248 Type & Select Correct Answer 1 Mobile-bearing TKA 82% (1496/1835) 2 Posterior stabilized fixed bearing TKA 4% (71/1835) 3 Cruciate retaining fixed bearing TKA 10% (192/1835) 4 Constrained TKA 2% (33/1835) 5 Mobile-bearing hinged TKA 2% (35/1835) L 2 Question Complexity D Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 1
All Videos (4) Podcasts (2) Login to View Community Videos Login to View Community Videos 2018 Orthopaedic Summit Evolving Techniques Pro: Wrong! Wake Up Old Man! ACL/PCL Substituting - Fred D. Cushner, MD (OSET 2018) Fred D. Cushner Recon - TKA Prosthesis Design 7/25/2019 223 views (1) Login to View Community Videos Login to View Community Videos 2018 Orthopaedic Summit Evolving Techniques Pro: It’s All About The Medial Congruent Design - Wayne G. Paprosky, MD (OSET 2018) Wayne Paprosky Recon - TKA Prosthesis Design 7/25/2019 222 views (1) Login to View Community Videos Login to View Community Videos 2017 HSS Holiday Knee & Hip Course Implant Evolution Over the Years: The Good, The Bad, and The Ugly - Timothy Wright, PhD Recon - TKA Prosthesis Design 8/31/2018 665 views (2) Question Session⎪TKA Prosthesis Design & Lumbar Disc Herniation Orthobullets Team Recon - TKA Prosthesis Design Listen Now 25:24 min 11/5/2019 19 plays (0) Recon⎪TKA Prosthesis Design Team Orthobullets 4 Recon - TKA Prosthesis Design Listen Now 10:46 min 10/24/2019 225 plays (3) See More See Less
2019 Annual Holiday Knee & Hip Course Left knee pain, valgus deformity and history of GSW in 56F (C101315) Jason L. Blevins Recon - TKA Prosthesis Design E 10/25/2019 10044 42 13 PREOP TKA PATIENT WITH CYST THAT BREACHES POSTERIOR TIBIA CORTEX. (C2566) Recon - TKA Prosthesis Design E 4/16/2016 590 9 11 Bilateral TKR, one s/p medial condyle fx (C2548) Arungeethayan Rajniashokan Recon - TKA Prosthesis Design E 4/1/2016 388 14 6