Arthroplasty - RC Q's Flashcards
RC 2009 With regards to patellar resurfacing. All of the following except: <ol> <li>Metal backed patella do better than all poly</li> <li>Rotation of 3-5deg of femoral component is better than neutral</li> <li>Subluxation is more common than dislocation</li> <li>Lateralizing femoral component helps</li></ol>
A<div>Garcia RM (CORR 2008) Isolated all-poly patellar revision for metal-backed patella failure<br></br></div>
RC 2017 - Increasing articular congruity of a polyethylene tibial component in a fixed bearing TKA will have what effect? <ol> <li>Decreased contact stress in the polyethylene</li> <li>Decreased patellofemoral maltracking</li> <li>Decreased forces at tibial tray interface with bone</li> <li>Increased posterior tibial roll-back (yes it said tibial)</li></ol>
A.<div><ul> <li>Increased conformity at the tibiofemoral articulation increases contact area and reduces contact stresses in total knee arthroplasty</li> <li>Increasing congruity = more constraint = increase in force @ tibial tray-bone interface</li></ul></div>
RC 2009 - What is true about mobile bearing TKR’s? <ol> <li>Better flexion</li> <li>No benefit shown in literature</li> <li>Better wear properties</li> <li>Longevity</li></ol>
B.<div><ul> <li>Allows motion at the interface between the undersurface of the tibial polyethylene and the top surface of the tibial base plate.</li> <li>Advocates believe it allows for increased ROM, lower polyethylene stresses, and a more idealized kinematic knee function.</li> <li>Increasing conformity of tibial liner implants reduces polyethylene stress but increases stress at the tibial fixation interfaces.</li> <li>A theoretical advantage for mobile-bearing TKA is that the articular surface of the implant can be congruent over the entire ROM without increasing constraint.</li> <ul> <li>This leads to lower contact stresses as a result of increasing contact area.</li> <li>Some authors believe lower contact stresses will translate into a lower incidence of osteolysis.</li> </ul> <li>Data do not exist to show whether these apparent advantages with regard to contact stresses actually translate into decreased wear and osteolysis in vivo.</li></ul></div>
RC Exam - When doing a PCL-sacrificing total knee arthroplasty which is true? <ol> <li>can raise joint line 12mm </li> <li>resection of PCL increases flexion arc 3-5mm</li> <li>better ROM postop with PCL retaining (or vice versa)</li> <li>better long term outcome with PCL-sacrificing (or maybe retaining)</li></ol>
B - the rest are false<div><ul> <li>PCL retaining knees have better survival</li> <li>Slightly better ROM with sacrificing –> but not clinically significant</li> <li>All patients getting arthroplasty have slight elevation of joint line, but no difference between implant types; elevating joint>8mm leads to poor outcomes</li></ul></div>
RC 2008 - Regarding the mechanical axis in the tibia, all are true except? <ol> <li>Colinear and parallel in coronal plane</li> <li>Colinear and parallel in sagittal plane</li> <li>Mechanical and anatomical tibia axes are colinear</li> <li>LE axis passes 8 mm medial to tibial spines</li></ol>
“<div>tibia coronal plane is equal for anatomic and mechanical axes</div><div><br></br></div><div>C - true in coronal plane</div>D - true<div><br></br></div><div><img></img><br></br></div>”
<div>RC 2012 - 6 anatomical releases for balancing a varus knee</div>
<ul> <li>Removal of osteophytes</li> <li>Medial capsule</li> <li>Posterior oblique ligament</li> <li>Superficial MCL</li> <li>Semimembranosus fibres</li> <li>PCL</li> <li>Pes anserine</li> <li>Medial Gastrocnemius</li> <li>Deep MCL</li></ul>
RC 2016 - List 4 soft tissue releases for a valgus knee in TKA
<ul> <li>IT Band</li> <li>Posterolateral Capsule</li> <li>LCL</li> <li>Popliteus Tendon </li> <li>Lateral Head of Gastrocnemius</li> <li>PCL</li></ul>
<div>RC 2014, 2011 - List 3 technique to determine rotation of the femoral component in TKA.</div>
“<ul> <li>Trans-epicondylar axis</li> <li>Perpendicular to Whiteside’s Line</li> <li>3o ER from posterior condylar axis</li> <li>Parallel to cut surface of tibia (gap balancing)</li> <li>Computer Navigation</li><li>IF DOING DFR: LINEA ASPERA, PF TRACKING</li> <ul> <li><img></img></li> </ul></ul>”
RC 2012 - Why do you ER the femoral component in a TKA <ol> <li>Brendan likes boys</li> <li>Make a rectangular flexion gap</li> <li>Because Femur is 6 degrees and tibia 3 degrees</li></ol>
“B.<div><br></br></div><div><img></img><br></br></div>”
RC 2011 - When performing TKA for varus knee, medial side is tight. Release semimembranosus. What does this effect? <ol> <li>It affects flexion gap more extension gap</li> <li>It affects both flexion and extension equally</li> <li>It affects extension gap more than flexion gap</li> <li>It affects the flexion gap only if the PCL is gap</li></ol>
C.<div><br></br></div><div><ul> <li>JAAOS - Soft Tissue Balancing in the Varus Knee</li> <ul> <li>sMCL will improve flexion and extension gaps</li> <li>POL affects mostly extension space</li> <li>Semimembranosus tendon affects extension space more than flexion</li> <li>Pes Tendons –> affect extension gap (surprising) - Campbells says that pes tendons affect flexion gap more</li> </ul></ul></div>
RC 2014 - List 3 soft tissue releases to improve your flexion gap in performing a TKA
<ol> <li>Posterior Capsule</li> <li>Gastrocnemius</li> <li>Medial and lateral posterior corners</li> </ol>
<ul> <li>popliteus</li> </ul>
<ol> <li>PCL</li> <li>Anterior superficial MCL</li></ol>
RC 2010 - Surgeon wants to use extramedullary referencing for tibia cuts in a total knee arthroplasty. If he ignores the rotational mismatch between the ankle and the tibial tubercle, what will the result? <ol> <li>No coronal malalignment </li> <li>Varus malalignment on coronal</li> <li>Valgus malalignment on coronal</li> <li>Increase posterior slope cut into tibia</li> </ol> <div><br></br></div>
“B.<div><ul> <li>JBJS. 2005. The effect of ankle rotation on cutting of the tibia in total knee arthroplasty.</li> </ul> <ul> <li>When an extramedullary alignment guide is used to prepare the tibia in total knee arthroplasty, varus alignment of the tibial component can occur because of a rotational mismatch between the proximal part of the tibia and the ankle joint</li> <li>The AP axis of the ankle is usually ER in relation to the AP axis of the proximal tibia</li> <li>This results in lateral displacement of the extra-medullar tibial guide if it is lined up with the AP axis of the ankle distally</li> <li>This will result in more medial bone resection proximally on the tibia, creating varus malalignment of your TKA</li> <li>To avoid tibial malalignment, it is important to first place the extramedullary alignment guide at right angles to the proximal tibial anteroposterior axis and then the distal end of the extramedullary guide should be placed at the center of the ankle joint</li> </ul> <div><img></img></div></div>”
RC 2012 - 6 types of failure of a TKA requiring a revision
<ul> <li>Infection</li> <li>Patello-femoral instability</li> <li>Aseptic Loosening/Osteolysis</li> <li>Extensor Mechanism Disruption</li> <li>Peri-prosthetic Fracture</li> <li>Instability (varus/valgus)</li> <li>Arthrofribrosis/Stiffness</li> <li>Metal Allergy</li></ul>
RC 2015 - What is the only advantage <b><u>to not </u></b>resurfacing the patella in TKA? <div> a. less complications</div> <div> b. decreased dislocation</div> <div> c. improved patellar tracking</div> <div> d. less anterior knee pain</div>
A.<div><ul> <li>JAAOS 2000 - Patellar Resurfacing in TKA</li> <ul> <li>“…complications included patellar fracture, patellar subluxation or dislocation, exten- sor mechanism disruption, and component wear, loosening, or dissociation. Many of these complications occurred only with, or <b>were much more common with, resurfaced patellae</b>.” </li> </ul> <li>(CORR 2005) Failure to resurface the patella during total knee arthroplasty may result in <b><u>more knee pain and secondary surgery</u></b></li> <ul> <li>Meta-analysis</li> <li>More anterior knee pain without patellar resurfacing</li> </ul></ul></div><div><br></br></div>
RC 2012, 2010, 2009 - Bilateral TKA, what risk goes up?<ol> <li>DVT</li> <li>Bleeding</li> <li>CV events</li> <li>Periprosthetic infections</li></ol>
C.<div><br></br></div><div><div>Restrepo C (JBJS 2007) Safety of Simultaneous Bilateral TKA: A Meta-analysis</div> <ul> <li>150 articles with 27,807 patients included</li> <li>Simultaneous TKA:</li> <ul> <li>Higher:</li> <ul> <li>Higher PE (OR 1.8)</li> <li>Cardiac complications (OR 2.49)</li> <li>Mortality (OR 2.2)</li> </ul> <li>Lower:</li> <ul> <li>DVT (not significant though)</li> </ul> </ul></ul></div>
RC 2008 - HO and TKA, risk factors - all of the following except <ol> <li>Femur Notching</li> <li>RA</li> <li>Manipulation post-op</li> <li>Female with hypertrophic osteoarthropathy</li></ol>
B.<div><br></br><div><div>Patients at high risk for developing HO after TKA include those with limited post-op knee flexion, increased lumbar BMD, hypertrophic arthrosis, excessive periosteal trauma, notching of the anterior femur, those who require forced manipulation after TKA</div></div><div><br></br></div></div>
RC 2017 - 75 female, 18 months post TKA, comes in with ongoing pain. States it “never felt good”. ROM is full. What is most likely diagnosis? <div>A. Stress fracture</div> <div>B. Infection</div> <div>C. Aseptic loosening</div> <div>D. Ligament instability</div>
D.
RC 2011 - Patient has TKA, wakes up with peroneal nerve injury in PACU. What was their deformity <div>A. Rigid Varus</div> <div>B. Rigid Valgus with flexion contracture</div> <div>C. Correctable varus</div> <div>D. Correctable valgus</div> <div></div>
B.<div><br></br></div><div><div>Peroneal nerve palsy = correction ofvalgus and flexion contracture deformityhas highest risk of peroneal nerve palsy</div></div><div><br></br></div>
RC 2016 - A patient is 8 weeks postop from a TKA and has significant stiffness. Given an AP, skyline and lateral x-ray which are totally normal. What do you do? <ol> <li>Manipulate under anesthesia</li> <li>Revise to stemmed components</li> <li>Arthroscopic lysis of adhesions</li> <li>Open lysis of adhesions</li></ol>
A.<div>Patients with early-onset stiffness (<90o of flexion or significant flexion contracture < 3 months after surgery) and had adequate preoperative and intra-operative Rom but are not progressing with physical therapy should be considered for manipulation <div></div></div><div><br></br></div>
RC 2011 - Most important predictor of post-op ROM of TKA <ol> <li>Use of PS knee</li> <li>pre-op motion</li> <li>high flex knee</li> <li>participation in PT</li></ol>
B. dont be dumb
RC 2009 - Hemophiliac has a TKA. All of the following are true, except: <ol> <li>Need to keep factor levels at 60% x 2wks post</li> <li>Lots of problems w/ joint instability</li> <li>If you take away infection, revision rates = everyone else</li> <li>Post op hemarthrosis is most common at 4-7d post op</li></ol>
B<div><br></br></div><div>-pts are stiff, not lax</div><div><b>-higher risk of infection! (MCQ 2008)</b></div><div>-replace to 100% pre-op then 60% post-op</div><div><ul> <li>Two hours pre-op replace factor level to 100% with IV infusion</li> <ul> <li>Check for factor level with factor assay</li> </ul> <li>Intra-operative- keep factor at >60%</li> <li>Post-operative in hospital- keep factor at >60% until discharge</li> <ul> <li>Recheck levels every 1-2 days</li> </ul> <li>Post-operative at home- keep factor at 30-60% normal level for 2 weeks post-op</li></ul></div>
<div>RC 2017, 2015, 2014 - For post-traumatic or post-operative arthrofibrosis of the knee, which is true?</div>
<ol> <li>Hoffa sign can help determine suprapatellar scarring</li> <li>Anterior arthrofibrosis prevents extension</li> <li>Manipulation under anesthesia should be performed within 12 weeks</li> <li>Flexion contracture of 5-10 degrees is usually well tolerated</li></ol>
“C.<div><br></br></div><div><ul> <li>The Hoffa test is for prepatellar fat pad. Firm pressure is applied with the thumb inferior to the patella outside the margin of the patellar tendon with the knee in (a) 30–60° of flexion. (b) The knee is fully extended, and increased pain in the infrapatellar fat pad indicates a positive test. The test is repeated on both the medial and lateral side</li> <li>One stem version refers to ““Anterior interval fibrosis””.</li> <ul> <li>Fibrosis of the posterior border of the IFP to the anterior surface of the tibia or transverse meniscal ligament, is termed ‘anterior interval scarring’, which effectively adheres the IFP to the anterior tibia.[7,8,56] If clinical presentation includes distal displacement of the patella (patellar infera), significant flexion contracture and decreased patellar mobility, the diagnosis of ‘infrapatellar contracture syndrome’ has been used</li> </ul> </ul> <ul> <li>JAAOS - Stiffness after Total Knee Arthroplasty:</li> <ul> <li>Patients with late-onset knee stiffness (>3 months after TKA and after adequate ROM had been achieved initially) are less likely to benefit from physical therapy</li> <li>"”Controversy continues regarding both the usefulness and timing of manipulation””</li> </ul> <li>Issa K (JBJS 2014) The Effect of timing of manipulation under anesthesia to improve range of motion and functional outcomes following total knee arthroplasty</li> <ul> <li>144 MUA - comparison of <6 weeks, 6-12 weeks, 13-26 weeks, >26 weeks</li> <li>Early manipulation gained more motion (36 vs 17o) and had higher final ROM</li> <li>No difference between <6 weeks and < 12 weeks</li> </ul></ul></div>”
RC 2015, 2014, 2010 - 45yo male presents 8mos post TKA with ROM 0-70 (0-120 pre-op). What are 3 possible causes of his flexion deficiency
<ul> <li>Technical Errors:</li> </ul>
<ol> <li>Gap imbalance (ie too tight in flex)</li> <li>Component Malalignment, malrotation</li> <li>Patellofemoral overstuffing</li> <li>Joint line elevation/patella baja</li> <li>Posterior cement extra-vasation</li> </ol>
<li>Patient Factors:</li>
<ol> <li>Poor Pre-op ROM</li> <li>Poor patient motivation/rehabilitation</li> <li>Poor pain control</li> <li>Heterotopic ossification</li> <li>Aggressive anti-coagulation with hematoma</li> <li>Infection</li> </ol>
<li>Factors that do NOT affect ROM:</li>
<ol> <li>Obesity, previous OR, Keloid scar, age, sex, mutiple joint involvement, bilateral TKA</li> </ol>
<div>RC 2015 - What is not a block to flexion following knee surgery:</div>
<ol> <li>Cyclops lesion</li> <li>Quads adhesions</li> <li>Adhesions in medial/lateral gutters</li> <li>Patella baja</li></ol>
A.<div><ul> <li>Cyclops lesions - anterior arthrofibrosis –> extension loss</li> <li>Quads adhesion –> tightening of extensor mechanism</li> <li>Patella baja –> shown to decrease flexion in TKA due to joint line elevation</li> <li>Arthrofibrosis –> causes decreased ROM in both directions</li></ul></div>
- External rotation of tibial and femoral components
- Lateralization of tibial and femoral components
- Medialization of patellar component
- Xray
- Physical exam
- Metal subtraction CT
- MRI
- Prior radiographs can aid in the evaluation of component position as well as assessment of component migration over time
- CT can provide detailed information regarding rotational malalignment of the femoral or tibial component
- Recurrence of deformity
- Loss of posterior slope
- Patella baja
- Compartment syndrome
- Mal-union and non-union
- Peroneal nerve palsy
- Patient Factors
- Inflammatory arthritis
- BMI > 35
- Flexion contracture > 15deg
- Knee Flexion < 90
- Deformity
- >20o varus/valgus deformity
- Patellar arthritis
- Ligamentous instability/thrusting gait
- Can consider combined ACL reconstruction (controversial)
- JAAOS 2005 - HTO/JAAOS 2011
- Easy to control correction (can dial it in)
- Less extensive surgical dissection/no disruption to proximal tib/fib joint
- Less proximity to peroneal nerve
- Can be combined with PF procedures
- No loss of lateral bone stock
- In an ACL deficient knee, placing the bone wedge posteromedially will decrease the tibial slope and decrease anterior translation
- In a PCL deficient knee, placing the bone wedge anteromedially will increase the tibial slope and increase posterior translation
- Placing the bone wedge direct medial will not affect the slope
- Smaller anterior gap with a larger posterior gap will preserve the native tibial slope
- 2015
- Increased tibial slope will DECREASE posterior translation
- JAAOS 2011 - Role of the HTO in the varus knee
- ACL deficiency --> decrease tibial slope
- PCL deficiency --> increase tibial slope
- Noyes (AJSM 2005) Opening wedge tibial osteotomy: the 3-triangle method to correct axial alignment and tibial slope
- Because you used low molecular weight heparin, the patient is not at risk for thrombocytopenia.
- You need to start the HIT work up if platelets drop below 100,000.
- It can present 4 to 5 days after starting heparin
- Ahmen I (Postgrad Med J 2007) Heparin Induced thrombocytopenia: diagnosis and management update
- 0-3 points - HIT unlikely
- 4-5 - intermediate possibility
- 6-8 highly likely
- LMWH
- Mechanical compression devices
- Rivoroxaban
- ASA
- CHEST Guidelines 2012
- “In patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA), we recommend use of one of the following for a minimum of 10 to 14 days rather than no antithrombotic prophylaxis: low-molecular-weight heparin (LMWH), fondaparinux, apixaban, dabigatran, rivaroxaban, low-dose unfractionated heparin (LDUH), adjusted-dose vitamin K antagonist (VKA), aspirin (all Grade 1B), or an intermittent pneumatic compression device (IPCD) (Grade 1C).
- Several patient factors were associated with increased risk of developing cardiac complications
- Caucasian ethnicity
- Obesity
- Chronic obstructive pulmonary disease
- Hypertension
- End stage renal disease (ESRD)
- Age greater than 65 years
- Coronary artery disease
- Congestive heart failure (CHF)
- Cup in 55o abduction
- Increase in head size
- Patient Factors:
- Obesity
- Decreased BMD
- Inflammatory arthritis
- Female gender (2x)
- Intra-operative (85% of fractures)
- Notching of femoral neck
- Excessive prosthesis varus (<130O)
- Femoral neck cysts
- Improper implant seating
- 2.5
- 4.5
- 6.5
- 8.5
- 2012, 2013
- Journal of Biomechanics (2001) - Hip contact forces and gait patterns from routine activities
- The average peak forces of the patients during normal walking at about 4km/h were between 211and 285% bodyweight.
- Obturator NV bundle
- External iliac
- Superior gluteal NV bundle
- Inferior gluteal NV bundle
- AIIS to center of acetabulum
- ASIS to center of acetabulum
- Ischial tuberosity to center of acetabulum
- Cannot remember the last option
- A line drawn through the centre of the femoral head to 1.5 cm medial to center of knee
- A line drawn through the centre of the femoral head to 1.5 cm lateral to center of knee
- A line drawn through the centre of the femoral head and intersecting the anatomic axis at the intercondylar notch
- A line bisecting the medullary canal
- larger head
- smaller head
- troch bursitis secondary to altered soft tissue tension
- position of cup at 40 degrees inclination and 15 degrees anteversion
- Abductor weakness
- Reduces trendelenberg gait
- Will cause a limp
- Increased joint reaction forces
- Miller's Review p383
- By advancing greater trochanter distally, the abductor complex is tensioned tighter, which increases hip compression forces
- Instability/Dislocation
- Impingement
- Aseptic Loosening
- Bearing surface wear/pelvic osteolysis
- Revision Surgery
- Psoas Irritation
- Leg Length Discrepancy
- Flexion and internal rotation
- Flexion and external rotation
- Extension and internal rotation
- Extension and external rotation
- Hip Instability. Smith and Sekiya. Sports Med Arthrosc Med 2010.
- The iliofemoral ligament (Y-ligament of Bigelow) is the strongest hip capsule ligament. It lies anterior to the femoral head and helps to resist anterior translation during external rotation and extension.
- For anterior dislocations, patients should refrain from hip hyperextension and external rotation for 6 weeks.
- Use a larger head
- Placing a collar on the femoral neck
- Increasing the offset
- Increasing the acetabular anteversion
- Primary Arc Range is controlled by the head/neck ratio:
- Best stability is achieved by maximizing head/neck ratio
- Things that decrease arc range:
- Neck skirt (femoral head collar)
- Acetabular hood
- Constrained cups
- Glut med split with Hardinge approach
- Retractor placement with Kocher Langenbach
- When doing a GT osteotomy
- Superior gluteal nerve innervates Glut med, glut min, and TFL
- The superior gluteal nerve runs between the glut medius and glut minimus about 5 cm above the GT. During your approach to the hip it can be damaged if you do not limit your glut medius dissection
- place a tagging suture 5 cm above the greater trochanter
- Sciatic (peroneal division)
- Obturator
- Superior Gluteal Nerve
- Femoral Nerve
- Injured w/ posterior acetabular retractor placement
- Injured w/ anterior or lateral traction on the femur
- The sciatic nerve is the nerve most commonly injured during THA. It was involved in over 90% of the 53 nerve injuries reported by Schmalzried et al in their series of more than 3,000 cases.
- The peroneal division of the sciatic nerve is more susceptible to injury than the tibial division. Schmalzried et al found that 94% of the sciatic nerve injuries in their study involved the peroneal division. The peroneal division may be more susceptible to stretch injuries because it is relatively more fixed between the sciatic notch and the fibular head as well as the density of the fibers within the nerve
- Most completely recover
- 70% have subclinical EMG changes
- more common in females
- more common in revisions
- Decreased fracture
- Decreased oxidization
- Increased cost
- Decreased wear
- In vitro studies:
- Reduced fracture toughness
- Reduced resistance to fatigue crack propagation
- Smaller particle generation which is possible more biologically active
- Mode 1
- Mode 2
- Mode 3
- Mode 4
- Mode 1 – primary bearing surface to primary bearing surface (1x1)
- Mode 2 – primary x secondary (2x1=2)
- Mode 3 – 3rd body
- Mode 4 – Wear between 2 non bearing surfaces, ie. 2 secondary surfaces (such as backside wear or neck socket impingement) (secondary surface x secondary surface – 2x2=4)
- exothermic to 75 degrees
- stronger in tension than compression
- does not have adhesive properties to implant
- Porosity reduction increases strength by 10-15%
- Acts as a grout, not an adhesive
- Poor tensile and shear strength, strongest in compression
- Reducing porosity increases cement strength and decreases cracking
- Have an unusually low wear (actual sentence)
- Have higher third body wear
- Poor biocompatibility and wettability
- Must titanium trunion (?)
- Alumina ceramics are extremely hard and scratch resistant, provide excellent biocompatibility (C not true), have superb chemical and hydrothermal stability as well as an extremely low coefficient of friction, are hydrophilic with superior lubrication, and offer superior wear resistance compared with other available bearing surfaces
- The major advantages of ceramic-on-polyethylene bearings include hardness, scratch resistance, a lower coefficient of friction compared with other available bearings, increased wettability for improved lubrication, and superior wear resistance. In the presence of third-body wear, their scratch resistance offers a further advantage over cobalt-chromium heads (B not true).
- large head metal on metal
- small head metal on metal
- head on crosslinked poly
- ceramic on ceramic
- Ceramic bearings have the lowest wear rates of any bearing combination (0.5 to 2.5 µ per component per year)
- ceramic-on-polyethylene bearings have varied, ranging from 0 to 150 µ
- MoM form smaller wear particles vs MoP (2.5 to 5.0 µ per year) and have less wear than MoP, but still more wear than CoC
- MoM higher serum metal ions, lower volumetric wear than MoC
- Vacuum mixing PMMA
- Pressurized
- Use of a cement plug
- Retrograde filling
- Third-generation techniques: porosity reduction, pressurization, pulsatile lavage
- Although vacuum mixing PMMA is recommended to reduce fumes and reduce porosity of cement, it is not technically included in classical third generation cement techniques
- More biocompatible than other metals
- More ingrowth in pores compared to other porous coated metals
- Greater friction at bone-metal interface
- Young's modulus of tantalum more closely approximates bone than that of titanium
- All metal has excellent biocompatibility
- JAAOS 2006 - Applications of Porous Tantalum in THA
- High volumetric porosity (70-80%), low modulus of elasticity, high frictional characteristics
- Excellent biocompatibility
- Modulus of elasticity similar to that of subchondral bone, but ultimate and yield strength much stronger
- Improved ROM
- Increased stability
- Decreased impingement of GT on pelvis
- Improved joint reactive forces - decreased wear/loosening
- Increased abductor strength/decreased limping
- well-positioned cup with GT nonunion
- well-positioned cup with absent GT
- mal-positioned cup with absent GT
- mal-positioned cup with GT non-union
- Decreased notching due to increased varus in the component
- Increased corrosion
- Increased osteolysis
- Increased soft tissue reaction
- JBJS 2014 - early corrosion-related failure of the rejuvenate modular total hip replacement
- JAAOS 2016 - Corrosion of the Head-neck Junction after Total Hip Arthroplasty
- Active or remote infection
- Presence of well-functioning, painless arthrodesis
- Neuromuscular disease causing potential instability
- Medically unfit
- Non-ambulatory patients/lack of active muscle power
- Active Charcot Neuroarthropathy
- Asymptomatic Arthritis
- Insufficient soft tissues
- Metal on Poly
- Pros: Longest track record, cheap, most modularity
- Cons: trunnionosis, higher wear rate cf the rest
- Ceramic on Poly
- Pros: good track record, lower wear rate than MoP
- Cons:
- Ceramic on Ceramic
- Pros: lowest wear rate, inert particles (no cancer risk)
- Cons: squeaking, fracture, price
- Acetabulum:
- Increased anteversion
- Deficient anterosuperiorly
- Difficulty identifying true acetabulum
- Deficient bone stock
- Femoral Side:
- Increased anteversion
- Small diameter canal
- Increased anterior bow of femur
- Valgus neck shaft angle
- Soft Tissues:
- Tensioning of sciatic nerve by leg lengthening
- May need femoral shortening osteotomy
- Contracted, deficient abductors
- Patient Factors
- Older Age
- Asymptomatic dysplasia
- Non-ambulatory
- Loss of ROM
- Morbid obesity (relative)
- Radiographic
- Tonnis Grade 2/3 OA
- Pre-op CEA<0, coronal CEA <5
- Incongruent Abd-IR (Van Rosen)
- Os-acetabuli (calcified labrum)
- Patient Factors:
- Renal Failure
- SLE
- Post-transplant
- Radiation therapy
- Hematologic Disorder (sickle cell, hypofibrinolysis, thrombophilia)
- Dysbarism
- Storage Diseases (Gaucher's)
- Drugs: Steroids, EtOH
- Trauma: femoral neck/head fracture, dislocation
- arthroplasty
- core decompression
- fibular allograft
- bisphosphates
- Total hip arthroplasty
- Pros: most reliable, early weight bearing
- Cons: will need revision in future given young age, relatively higher rate of dislocation
- Hip resurfacing
- Pros: preserves bone stock
- Cons: childbearing age - technically a contraindication, same with AVN
- Flexion osteotomy
- Cons: already complete collapse --> precludes this option; may make future THA more difficult if
- Bipolar
- Cons: too young, will destroy acetabular cartilage and need revision to THA
- Move GT distally
- Move GT laterally
- Acetabular exposure
- Over reaming of anterior and posterior walls
- Bone scan
- WBC Scan
- Aspiration and nuclear med
- Nothing
- Instability
- Infection
- Pain
- LLD
- Dora C (JBJS Br 2007) Iliopsoas impingement after THA: The results of non-operative management, tenotomy or acetabular revision
- Review of 30 hips with well-fixed but mal-positioned or over-sized cups and iliopsoas tendonitis
- 86% of patients with surgery had improvement
- Conservative management failed in all cases
- No benefit between tenotomy and acetabular revision at 2 years, revision had higher initial complications
- JAAOS 2009 - Anterior Iliopsoas Impingement and Tendinitis after THA
- Non-surgical treatment successful in only 39% of cases in our literature review
- Vancouver Classification:
- Location of fracture
- Stability of implant
- Bone stock available
- Other:
- Pre-operative medical optimization/function
- Abductor deficiency (constraint)
- Acetabular component stability (dual revision)
- Previous components
- Intrinsic Hip
- Infection
- Aseptic loosening of acetabular component/Pelvic osteolysis
- Dislocation/instability
- Synovitis secondary to wear debris
- Periprosthetic fracture
- Pseudotumor
- Heterotopic ossification
- Extrinsic
- Hernia
- Psoas tendonitis
- Stress fracture of pelvis
- Lumbar spine disease
- GU/Gyne/Abdo
- Cam: (no good cut off evidence)
- DECREASED head-neck offset (<8-9mm)
- Alpha angle > 55-60o
- Pistol Grip Deformity
- Triangular index>1
- Pincer:
- Acetabular Retroversion:
- Cross-over sign
- Ischial spine sign
- Posterior Wall Sign
- Global Overcoverage:
- Lateral CEA > 40o
- Down-sloping sourcil
- Coxa profunda
- Protrusio acetabuli
- Tonnis angle < 0o
- L1 radiculopathy
- Retroverted acetabulum causing Pincer impingement
- Shape of femoral head is normal in CAM impingement
- Impingement related hip pain typically occurs when seated for long periods or after activity.
- Blankenbaker DG (Semin Musc Radiol 2013) Non-Femoral Acetabular Impingement
- Ischiofemoral Impingement Syndrome
- Narrowing between ischial tuberosity and LT --> QF gets pinched
- Abnormal contact between AIIS and proximal femur
- Thickened or taut psoas at acetabular rim/anterior hip capsule
- Pagets
- Females under 65
- Ankylosing Spondylitis
- Cementless Implants
- Risk factors:
- high risk
- men with bilateral hypertrophic OA
- history of HO in either hip
- post-traumatic arthritis characterized by hypertrophic osteophytosis
- moderate
- ankylosing spondylitis
- DISH
- Paget’s
- Unilateral hypertrophic OA
- Men > women
- Cementless femoral component
- Approach: extended iliofemoral > Kocher > ilioinguinal
- Femur Notching
- RA
- Manipulation post-op
- Female with hypertrophic osteoarthropathy
- Patients at high risk for developing HO after TKA include those with limited post-op knee flexion, increased lumbar BMD, hypertrophic arthrosis, excessive periosteal trauma, notching of the anterior femur, those who require forced manipulation after TKA
- Replace factors to 100%
- Coxa valga
- Infection rate similar to non-hemophiliac patients
- HO rate is decreased
- Two hours pre-op replace factor level to 100% with IV infusion
- Check for factor level with factor assay
- Intra-operative- keep factor at >60%
- Post-operative in hospital- keep factor at >60% until discharge
- Recheck levels every 1-2 days
- Post-operative at home- keep factor at 30-60% normal level for 2 weeks post-op
- coxa valga is true in haemophiliac
- Knee>elbow>ankle>hip
- Higher risk late infection,…..yrs down the road
- Early infection rate no difference
- Must cover salmonella
- Increased dislocation rate
- Increased early revision
- Increased deep infection
- Pre-op considerations:
- Pre-op osteomyelitis
- Intra-op bone cultures
- Other sources of infection often present (Sickle patients often get transient bacteremia)
- Avoid sickle cell crisis (lots of fluids, oxygenate, avoid acidosis)
- CHF often present with chronic anemia
- Pre-op transfusions/plasmapheresis
- Intra-op:
- Protrusio
- Widened canal – marrow hyperplasia
- Poor bone quality/multiple infarcts
- osteonecrosis
- Rule out other infections pre arthroplasty because patients with sickle cell hemoglobinopathies suffer from an unusually high infection rate related to functional asplenia.
- Post-op:
- THA infection rate between 16% and 20%
- Although the complication rate has been reported to be as high as 80% at 6-year follow-up and the revision rate as high as 63% at 6.5 years postoperatively, no reports of salmonella osteomyeltitis in sickle cell THA; don’t need coverage for salmonella (gram negative)
- Higher rate of hip dislocation – up to 26%
- IT band
- Iliopsoas
- Hamstring
- Labrum
- External Type:
- IT Band over GT
- Snaps going from hip flexion to extension
- Internal Type:
- Iliopsoas over iliopectineal eminence
- Snaps going from hip extension to flexion
- Intra-articular:
- Loose body
- Acetabular labrum - Usually posterosuperior labrum
- Patient factors
- Obesity BMI >30
- DM
- Post traumatic arthritis
- Chronic liver disease
- Glucocorticoid use, RA
- EtOH abuse
- Drug abuse
- Poor nutritional status (Albumin<5)
- Surgical factors
- Prolonged surgical time
- Prolonged wound drainage
- Hematoma
- Antibiotic loaded cement
- Shorter operating time
- Lower BMI
- Irrigation
- Single stage revision
- Two stage revision
- I&D and liner exchange
- I&D
- 2016 J of Arthroplasty Is there still a role for irrigation and debridement with liner exchange in acute periprosthetic total knee infection?
- They did liner exchange with extensive I+D in patients with acute infections (few than 3 weeks of symptoms and no immune compromise)
- Found that for all commers, irradication rate was 68.66%. If pseudamonas (66.67% failure rate) and MRSA (80% failure rate) were removed, success of I+D with liner exchange was raised to 85.25%
- Patient Factors:
- Renal Failure
- SLE
- Post-transplant
- Radiation therapy
- Hematologic Disorder (sickle cell, hypofibrinolysis, thrombophilia)
- Dysbarism
- Storage Diseases (Gaucher's)
- Drugs: Steroids, EtOH
- Trauma: femoral neck/head fracture, dislocation
- Impaction bone graft
- Simple cavitary defects
- Can augment segmental defects when using metal to convert to a contained defect
- Non-cemented Hemispheric Cup
- Preferred method in Type 1 and.2 defects
- Requires column and partial rim support
- Structural autograft
- Not an option, no longer have a femoral head
- Structural allograft
- Goal to give bony support for non-cemented cup
- Femoral head, distal femur, total acetabulum
- Porous modular metal implants/augments
- Goal to put in uncemented cup
- Usually srew it to the bone, then cement the cup to the augment (it is a noncemented cup though)
- Then bone graft
- Cup cage construct
- Triflange custom cup
- Oblong Cup
- Ring Cage Construct
- Ensure stability of implants or revise to stable implants
- Preserve endosteal femoral blood supply
- Bypass stems by minimum 2 cortical widths:
- Plate should span most if not entire length of femur
- Use screws AND cerclage wires
- Screws can be placed into cement mantle
- can raise joint line 12mm
- resection of PCL increases flexion arc 3-5mm
- better ROM postop with PCL retaining (or vice versa)
- better long term outcome with PCL-sacrificing (or maybe retaining)
- Approach
- Tourniquet time
- Implant type and manufacturer
- To know whether the TKA has an anterior notch
- Surgical hip dislocation and synovectomy
- Chemotherapy and resection
- Radiation and resection
- Total hip arthroplasty
- For example, a patient with synovial chondromatosis of the hip treated at our institution would undergo arthroscopic removal of loose bodies and arthroscopic synovectomy. He or she would not undergo open arthrotomy and surgical hip dislocation purely to facilitate a total synovectomy
- See notes
- More complications with dislocation
- Less recurrence with dislocation
- Arthroscopy technically challenging, cant access extra articular disease
- 10-15% in general population
- Generally Type 4 allergic reaction
- Delayed cell mediated with T lymphocytes
- Clinical Syndrome
- Dermatitis
- Eczema, usually on the knee but ca include whole body
- TXA is a synthetic drug that limits blood loss through inhibition of fibrinolysis and clot degradation.
- Surgical trauma is known to cause fibrinolysis, which increases with the use of a pneumatic tourniquet.
- TXA reversibly saturates the lysine binding site of plasminogen, preventing the interaction of the active protease, plasmin, with the surface-binding site on fibrin.
- This inhibits the degradation of a fibrin clot by plasmin.
- TXA is available in IV, topical, and oral forms
- Requires renal dosing
- Recommend 10-20mg/kg dose pre-incision and 3 hrs later to reduce bleeding, transfusion
- Can cause changes to vision/blurriness
- Rare occurrences of changes to color vision, retinal artery occlusion, central retinal artery/vein obstruction
- Hemo A is IX deficiency
- X-Linked recessive
- Females never get it
- There is a usually spontaneous occurrence
- Hemophilia is caused by a deficiency of clotting factor VIII or IX and is inherited by a sex-linked recessive pattern.
- von Willebrand disease, a common, moderate bleeding disorder, is caused by a quantitative or qualitative protein deficiency of von Willebrand factor and is inherited in an autosomal dominant or recessive manner.
- Inheritence pattern
- Congential hemophilia
- X-linked recessive disorder (typically affects males only)
- Aquired hemophila
- Rare condition with autoimmune ethiology, with no genetic inheritance
- Patients undergoing TKA, significant improvements were observed for function, quadriceps strength, and length of stay.
- Existing evidence suggests that pre-habilitation may slightly improve early postoperative pain and function among patients undergoing joint replacement; however, effects remain too small and short-term to be considered clinically-important, and did not affect key outcomes of interest (ie, length of stay, quality of life, costs).
Indications
Difficult knee exposure during revision (or primary) TKA.
The TTO is most commonly needed in cases of arthrofibrosis or patella baja.
A long tibial stem, cemented or press-fit, that cannot be removed via access to only the tibial plateau-baseplate interface but instead requires access to the tibial stem in the medullary canal to break up the ingrowth and/or cement fixation.
The patient must have good bone quality as assessed on radiographs.
There must be sufficient thickness of bone stock along the anterior aspect of the tibia (≥1.5 cm from the anterior TT to the deepest part of the osteotomy) after taking into account the existing cement mantle and tibial keel or stem.
Contraindications
Known osteoporosis (z-score −2.5).
Poor bone quality as assessed on radiographs.
Insufficient bone stock along the anterior aspect of the tibia.
Bone loss requiring reconstruction with a tibial cone, which will restrict fixation of the osteotomized bone fragment.
Comorbidities that may impede healing of the osteotomy fragment, such as tobacco use, diabetes, rheumatoid arthritis, and chronic steroid use
- Osteotomy length 8-10 cm (minimum 6 cm)
- Hinge laterally, maintain continuity lateral geniculate blood supply
- Rigid fixation 6.5 mm bicortical screw proximal, 2x 18g wires distal
- 18 g wires as far posterior as possible to avoid ST Irritation
A TTO can provide reliable and safe exposure during revision TKA with a high union rate, low complication rate, and predictable outcomes."
- This step leads to femoral components that are aligned in 2° to 4° more valgus and tibial components that are positioned in 2° to 4° more varus, while maintaining similar hip-knee-ankle angles and anatomic angles of the knee compared to a mechanically aligned knee.”
- Long-term data are still lacking on this alignment technique, and long-term studies with larger numbers are required before making any conclusions regarding this technique.
- Measured resection relies on 3 different femoral landmarks: posterior condylar axis (PCA), the transepicondylar axis (TEA), and Whiteside line.
- PCA is most commonly used. Has been noted to be IR 6° relative to the TEA.
- The TEA is typically thought to be the most reliable landmark for assessing femoral rotation and most closely recreates the patient’s natural femoral rotation.
- The Whiteside line is drawn along the deepest part of the trochlear groove, is perpendicular to the TEA, and has been shown to more consistently approximate appropriate external rotation compared to the PCA, even in valgus knees.
- Patient-specific Instrumentation
- Data supporting the claims for improved alignment, decreased outliers, decreased cost, and decreased blood loss are currently lacking.
- Computer Navigation
- Active systems typically involve robotic control to perform part of the procedure. Passive systems are more common, and the surgical procedure is entirely under direct surgeon control.
- CAS systems are also distinguished as either image based or image free.
- Numerous reports exist on the benefits of CAS.
- Meta-analyses have shown improved precision and accuracy in coronal alignment and improved femoral rotation.
- Use of CAS avoids violation of the femoral or tibial IM canals, which can theoretically decrease blood loss, and the risk of fat emboli syndrome.
- Studies have shown do difference in KSS up to 5 years port-op.
- Other disadvantages: increase OR time and a notable learning curve.
- Femoral pin site fractures occur at a rate of 1.3% and are more common with transcortical pin placement, and tibial stress fractures can occur as well.
- Additional costs can be mitigated in high-volume centers performing >250 cases per year.
- In a Canadian study of nearly 38,000 patients, surgeons who performed <35 THAs a year had a dislocation rate of 1.9% vs 1.3% for surgeons with greater volumes.
- It has been shown that for every 10 THAs performed, a surgeon's dislocation rate decreases by 50%.
- Institution volume also influences dislocation as demonstrated by a comparison of high- and low-volume centers.
- This study reviewed literature published in the last 10 years to investigate the reasons for revision failure.
- A total of 9,952 revisions were identified and it was determined that the number one cause of failure was aseptic loosening (23.19%), followed by instability (22.43%) and infection (22.13%).
- Further analysis of applicable revisions investigated BMI and age at the failure rates.
