-
osteolysis
- particulate debris
- macrophage activted osteolysis
- prosthesis micromotion
- particulate debris dissemination
-
radiostereometric analysis
most accurate/ precise way to measure wear of lolyehtylen
-
particulate debris formation types of wear
- adhesive wear
- abrasive wear
- third body wear
- linear wear
- volumetric wear
- olumetric wear more or less creates a cylinder
- V=3.14rsquaredw
- V is volumetric wear, r is the radius of head, w is linear head wear
- head size is most important factor in predicting particles generated
-
factors that increase wear THA
- thickness < 6mm
- malalignment of components
- patients < 50 yo
- men
- higher activity level
-
particulate size
< 1 micron
-
macrophage activate cytokines
- TNF alpha
- TGF beta
- osteoclast activating factor
- oxide radicals
- Hydrogen peroxide
- acid phosphatase
- Il-1; Il-6
- prostaglandins
-
osteoclast activation
- TNF increases RANK
- increase VEGF with UHMPWE enchances rank/ rankl
-
osteolysis blood test ( protein)
N-telopeptide urine level
-
PJI infection rate
TKA
THA
-
4 most common organisms for PJI
- s. aureus
- s. epidermidis
- coag neg staph
- candida
-
acute pji
chronic pji
- within 3-6 weeks ( cdc <90 days)
- - no biofilm production
- chronic
- -biolfilm forms after 4 weeks
- --15% cells/ 85% glycocalyx
- bone scan
- -99% sensitive /30-40 % specificity
-
PEt scan for PJI
sensitivity 98%/ specificity 98%
-
MSIS criteria
- major criteria
- -sinus tract
- -pathogenisolated from 2 seperate cultures
- minor criteria
- -elevated esr ( 30) or crp (>10)
- -elevated WBC (1,100 knees/ 3000 hips)
- -PMN ( >64% knees, >80 hips)
- -purulence in joint
- -pathogen isolatation in 1 culture
- ->5pmn in 5 hpf @ 400x
-
PJI LABS
- crp- peaks 2-3 days ; normal after 2-3 weeks
- -acute < 100 acute 10 mg/dl
- ESR- peak 5-7 days, ormalized after 3 weeks
- chronic over 30
- SIL-6- peak 8-12 hr after surgery, normal 3days
- sensitivity 100%/ specificity 95%
- false positive
- -RA
- -MS
- -AIDS
- -PAgets
-
PJI Surgical options
- poly exchange and iv abx 4-6 weeks
- --50-55% success rate
- one stage replacement
- -low virulence, no sinus tract healthy patient,no bone graft, no long abx use
- -abx impregnated cement
- -success 75-100%
- two stage
- -prosthesis removal, antibiotic spacer, IV antibiotics for 4-6 weeks and delayed reconstruction
- delayed reimplantation >6 weeks has a 70-90% success rate
- resection arthroplasty
- -total knee success rate is 50% to 89%
- -total hip success rate is 60% to 100%
- arthrodesis
- -71-95 % success
amputation
-
spacer abx mix
40g of cement shoud have 3g vanco and 4g tobramycin
highest doses without systemic toxicity
- 12.5g tobramycin:40g cement
- 10.5 vancomycin:40g cement
-
pji local abx choices
- aminoglycosides ( genta/ tobra)
- -gram neg bacilli
- -synergistic against g+ coc ( staph/entero)
-
incidence tha fracture
intraoperative fractures
- 3.5% of primary uncemented hip replacements
- 0.4% of cemented arthroplasties
postoperative fractures
- 0.1%
- most common at stem tip
-
risk factors femur fracture in THA (7)
- impaction bone grafting
- female gender
- technical errors
- cementless implants
- osteoporosis
- revision
- minimally invasive techniques (controversial)
-
vancouver intraop classification
- a1- proximal metaphysis, cortical perf
- a2- prox metaphysis non displaced crack ( wire)
- a3- prox metaphysis, unstable (fully porous coated stem/ tapered flute stem
- b1-diaphyseal, cortical perf ( fully porous bypass by 2 cortical diamter+/- strut)
- b2-diaphyseal, nondisplaced crack ( cerclage, fully porous)
- b3-diaphyseal, displaced unstable (fully porous)
- c1-distal to stem tip( bone graft, struth graft, fully porous)
- c2-distal non displaced crack, ( cerclage)
- c3- distal to stem unstable ( orif)
-
vancouver post op classification
a-fracture in troch-adress osteolysis ( GT less than 2cm conservative)
- b1-well fixed stem- orif, cerclage
- b2-loose stem good proximal bone stock -long porous cementless stem
- b3-poor proximal bone stock-prox femoral allograft/ proximal femoral repalcement
c-below plate - orif
-
causes of increased q angle
- internal rotation of femoral prosthesis
- medialization of femoral component
- internal rotation or medialization of tibia
- placing patella prosthesis to lateral
-
q angle
- asis to center of patella
- patella to tibial tuberosity
-
femoral prosthesis axis ( 3)
- whiteside line
- epicondylar axis ( parellel to tibia cut)
- posterior condylar axis
- -3 degree of internal rotation from transepicondyalr axis ( therefore rotate 3 degrees ext)
-
paprosky acetabular bone loss
type 1- minimal deformity, intct rim
type 2a- superior bone lysis with intact superior rim
type 2b- absent superior rim, superolateral migration
type 2c-localized destruction of medial wall
type 3a- bone loss 10am -2 pm superolateral cup migration
type 3b- bone loss 9am-5am, superomedial migration
-
aaos classification acetabular one loss
- type 1- segmental
- type 2- cavitary
- type 3- combined deficiency
- type 4-pelvic dicontuinity
- type 5 arthrodesis
-
aaos classfication femoral bone loss
- type 1- segmental
- type 2- cavitary
- type 3- combined
- type 4-malaignment
- type 5- stenosis
- type 6- femoral discontinuity
-
papropsky femur bone loss
- type 1- minimal metaphyseal bone loss
- type 2- extensive metaphyseal but intact diaphysis
- type 3- extensive metaphyseal , but atleast 4 cm diaphysis scratch fit
- type 3b- extensive, less than 4 cm
- type 4- extensive metaphyseal+ nonsupportive diaphysis
-
acetabular position recommended postion
anteversion 5-25%
abduction 30-50%
-
surgical aproach for version
posterior err towards more anteversion
anterior err to less anteversion
-
combined version ideal
37 degrees
-
pros of mobile bearing UKA
weightbearing throgh meniscuses increases conformity and contact without increasing constraint
decrease wear pattern
cons: harder, can dislocation
-
uka indications
classic: older than 60, low demand less than 82 kg
-
contraindications TKA (9)
- inflamm arthririts
- ACL deficiiency
- varus > 10 degrees
- valgus over 5 degrees
- rom restricted ( less than 90 degrees or flexion of 5-10 degrees)
- previous meniscectomy
- tricompartmental OA
- overweight
- grade 4 patellofemoral oa
-
mobile bearing UKA 15 year survivorship
93%
-
disadvantage metal on metal
- 12-24 months increase metal ions then hits steady state
- pseudotumors
- hypersensitivity type 4
- - te cell mediated ( macrophages)
- -antigen activated present to class 2 mhc
-
ceramic squeeking risk factord
- edge loading
- impingement and acetabular malposition
- third body wear
- loss of fluid film lubrication
- thin flexible titatnium stems
- stripe wear- cresent shape wear on head
-
HO THA complication: brooker
class I: represents islands of bone w/in soft tissues about hip
class II: inclues bone spurs in pelvis or proximal end of femur leaving at least 1 cm between the opposing bone surfaces;
class III: represents bone spurs that extend from pelvis or the proximal end of femur, which reduce the space between the opposing bone surfaces
-
Heterotropic ossification prophylaxis
600-800 GCY within 24-48 hour following procedure
oral indomethacin
-
pseudotumor workup
- metal ions( cobalt chromium on repeat visits)
- -MR with metal subtraction
- rule ut infection
-
sciatic nerve palsy THA
- 0-3 %
- peroneal nerve division most common ( 80%)
nerve closes to ischium care with posterior acetabular retraction when hip is flexed
-
sciatic nerve palsy THA risk factors
- DDH
- revision
- female
- limb lengthening
- post traumatic oa
- 35-40% recover full strneght
-
sciatic nerve palsy THA treatment
- hip in extension and knee in flexion
- immediate excvation in or
- AFO for foot drop
intraop- downsize compnents or subtroch osteotomy
-
hip osteonecrosis + risk factors
- risk factors:
- - irradation
- -trauma
- - leukemia/ lymphoma
- - caisson disease
- - sickle cell
- -gaucher disease
-
idiopathic avn- cascade
- coagulation of intraosseous microcirculaton
- venous thrombosis
- retrograde arterial occlusion
- intraosseous hypertension
- decreased blood flow femoral head
- avn of head
- chondral fracture and collapse
-
AVN femoral head
- femoral head fracture- 75-100%
- basicervical fracture 50%
- cervicotrochanteric fracture 25%
- hip dislocation 2-40% (2-10% if reduced within 6 hours)
- intertroch fracture
-
kerboul combined necrotic angle
low risk group- combined necrotic angle less than 190
moderate risk group- combined necrotic angle 190-240
high risk- combined necrotic angle of more than 240
take ant-post angle and add to lateral angle
-
external rotation on radiographs will
- falsely decrease offset
- create valgus appearing femoral neck
- falsely decrease femoral canal diameter
-
tear drop what makes it
created by superposition of the most distal part of the medial wall of the acetabulum and the tip of the anterior/posterior horn of acetabulum
-
steinberg classifcation avn
-
MRi finding AVN hip
double density appearance
- T1: dark (low intensity band)
- T2: focal brightness (marrow edema)
-
AVN hip treatment
- bisposphonates/ aspirin
- core decompression +/ - bone graft
- rotational osteotomy
- vascularized fibular bone graft
THA
-
Su classification
- 1- proximal to femur component
- 2-component and moves proximally
- 3-distal to upper edge of anterior flange
-
retrogade nail femur
may cause more posterior start point and therefore extension of femur
-
felix classification
- 1-fracture tibial plateau
- 2-fracture adjacent to ste
- 3- distal to stem
- 4- tibial tubercle
-
-
-
cell biology OA
- MMP
- tissue inhibitor MMP
- IL-1, Il-6, TNf-alpha
-
pe failure TKA
if less than 8mm
( measure from bottom of metal tray)
-
oxygen depleted PE
more resistant to abbrasive and adhesive wear
-
relative contraindications hip resurfacing
- coxa vara ( increased fracture)
- LLD
- female sex child bearing age ( metal ions)
- renal failure
-
Joint reaction force formula
Solving for joint reaction force (R)
step 1: calculate My
principle
- sum of all moments equals 0
- in this case, the moments are created by My and W
- equation
- (A x My) + (B x W) = 0
- assume A = 5cm and B = 12.5cm (this information will be given to you)
- My = 2.5W
step 2: calculate Ry
- Ry = My + W
- Ry = 2.5W + W
- Ry = 3.5W
step 3: calculate R
R = Ry / (cos 30°)
- R = 3.5W / (cos 30°)
- R = ~4W
-
actions that decrease joint reaction force
move acetabular component medial inferior and anterior
- femur:
- increase offset
- long stem prosthesis
- lateralize greater troch
- varus neck
cane contralateral hand
-
-
cocktail for TKA/THA6
- 60 ml levobuipvicaine 2.5%
- 30 mg ketorlac
- 0.5 mg adrenaline
- 40 ml NS
-
range of motion needs TKa
Range of motion
requirements
swing phase of gait
65° of flexion
activities of daily living
90° of flexion
stairs
95° of flexion
rise from a chair
105° of flexion
-
THA screw placement zone
- posterior superiod quadrant:
- -target zone
- elevate hip centre maybe sciatic at risk
- posterior inferior
- -caution zone
- -over 20 mm dangerous
- -sciatic nerve, inf gluteal vessels nerve, pudendal nerve vessel
- ant- inf zone is danger
- -obturator nerve and artery and vein
- ant sup quadrant
- -external illiac vessels at risk
-
midvastus approach tka- contraindications
- ROM <80 degrees
- obese patient
- hypertrophic arthritis
- previous HTO
-
varus deformity steps of release tka
- 1-deep mcl
- 2-medial osteophyte
- 3-release posteromedial corner
- 4-medialtibial reduction osteotomy
- 5- pcl release
- 6-release semimebranosus
- 7-pie crust mcl
- 8
-
valgus deformity release
- 1- osteophyte
- 2-posterolateral capsule
- 3-iliotibial band ( if tight in extension)
- 4-popliteus ( if tight in flexion)
- 5-LCL
-
felxion deformity release
- 1-osteophyte
- 2-posterior capsule
- 3-additional femur resection
- 4-gastrocnemius muscle
- ( done at 90 flexion)
-
causes patella baja
- proximal tibia osteotomy opening wedge
- tibia tubercle slide/ transfer
- proximal tibia trauma
- elevate joint line tka
- acl recon
-
insall salvati
less than 0.8 is patella baja
patella bone articualr surface length/ patellar tendon
-
how to deal patella baja TKA
- lower joint line( augment for distal femur, cute more tibia)
- repalce patella and put puck more proximal
tibia tubercle transfer
-
TKA heterotrophic ossification risk factors
- see on quas tendon and anterior femur hypertrophic arthrosis
- male gender
- obesity
- notching
- periosteal injury/ stripping
- post op knee effusion
- post op forced manipulation
-
furia and pellegrini classifcation
- class I: island of bone localized to suprapatellar soft tissues
- Class II: bone organized into areas of ossification contiguous with the anterior distal femur
- Grade A: less than or equal to 5 cm
- Grade B: greater than 5 cm
-
Popliteal artery
origin
- lies posterior to the posterior horn of the lateral horn of the lateral meniscus
- origin before knee
- a continuation of the superficial femoral artery
- transition is at hiatus of adductor magnus muscle
- anchored by insertion of adductor magnus as enters region of posterior knee
-
TKA FLAP possibility
medial gastrocnemius rotational flap (medial sural artery): anterior and medial defects
ateral gastrocnemius rotational flap (lateral sural artery): lateral defects
-
hip arthrodesis
- reduces efficiency of gate by 50%
- 30% more oxygen expenditure
- 20-35° of flexion
- 0°-5° adduction
- 5-10° external rotation
-
HTO
varus deformities
varus-producing high tibial osteotomy
success rate is 87% patients in 10 years
valgus-producing high tibial osteotomy
success rate is 50-85% of patients in 10 years
best results achieved by overcorrection of the anatomical axis to 8-10 degrees of valgus
specific contraindications
- narrow lateral compartment cartilage space with stress radiographs
- loss of lateral meniscus
- lateral tibial subluxation >1cm
- medial compartment bone loss >2-3mm
- varus deformity >10 degrees
-
HTO recurrence deformity
- 60% failure rate after 3 when
- failure to ovvercorrect
- patients are overweight
- loss of posterior sloe
- patella baja
- compartment syndrome
- peroneal nerve palsy
- malunion or non union
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