recon

• particulate debris
• macrophage activted osteolysis
• prosthesis micromotion
• particulate debris dissemination

most accurate/ precise way to measure wear of lolyehtylen

• 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

• thickness < 6mm
• malalignment of components
• patients < 50 yo
• men
• higher activity level

< 1 micron

• TNF alpha
• TGF beta
• osteoclast activating factor
• oxide radicals
• Hydrogen peroxide
• acid phosphatase
•  Il-1; Il-6
• prostaglandins

• TNF increases RANK
• increase VEGF with UHMPWE enchances  rank/ rankl

N-telopeptide urine level

• 1-2% TKA 
• revision 5-6%

• 0.3-1.3% THA
• 3-4%

• s. aureus
• s. epidermidis
• coag neg staph
• candida

• 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

sensitivity 98%/ specificity 98%

• 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

• 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

• 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

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

• aminoglycosides ( genta/ tobra)
• -gram neg bacilli
• -synergistic against g+ coc ( staph/entero)

• vanco
• -g+ cocci

intraoperative fractures

• 3.5% of primary uncemented hip replacements
• 0.4% of cemented arthroplasties

postoperative fractures

• 0.1%
• most common at stem tip

• impaction bone grafting
• female gender
• technical errors
• cementless implants
• osteoporosis
• revision
• minimally invasive techniques (controversial)

• 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)

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

• internal rotation of femoral prosthesis
• medialization of femoral component
• internal rotation or medialization of tibia
• placing patella prosthesis to lateral

• asis to center of patella
• patella to tibial tuberosity

• whiteside line
• epicondylar axis ( parellel to tibia cut)
• posterior condylar axis
• -3 degree of internal rotation from transepicondyalr axis ( therefore rotate 3 degrees ext)

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

• type 1- segmental
• type 2- cavitary
• type 3- combined deficiency
• type 4-pelvic dicontuinity
• type 5 arthrodesis

• type 1- segmental
• type 2- cavitary
• type 3- combined
• type 4-malaignment
• type 5- stenosis
• type 6- femoral discontinuity

• 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

anteversion 5-25%

abduction 30-50%

posterior err towards more anteversion

anterior err to less anteversion

37 degrees

weightbearing throgh meniscuses increases conformity and contact without increasing constraint

decrease wear pattern

cons: harder, can dislocation

classic: older than 60, low demand less than 82 kg

• 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

93%

• 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

• 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

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

600-800 GCY within 24-48 hour following procedure

oral indomethacin

• metal ions( cobalt chromium on repeat visits)
• -MR with metal subtraction
• rule ut infection

• 0-3 %
• peroneal nerve division most common ( 80%)

nerve closes to ischium care with posterior acetabular retraction when hip is flexed

• DDH
• revision
• female
• limb lengthening
• post traumatic oa
• 35-40% recover full strneght

• hip in extension and knee in flexion
• immediate excvation in or
• AFO for foot drop

intraop- downsize compnents or subtroch osteotomy

• 10% of THA
• 80% bilateral

• risk factors:
• - irradation
• -trauma
• - leukemia/ lymphoma
• - caisson disease
• - sickle cell
• -gaucher disease

• coagulation of intraosseous microcirculaton
• venous thrombosis
• retrograde arterial occlusion
• intraosseous hypertension
• decreased blood flow femoral head
• avn of head
• chondral fracture and collapse

• femoral head fracture- 75-100%
• basicervical fracture 50%
• cervicotrochanteric fracture 25%
• hip dislocation 2-40% (2-10% if reduced within 6 hours)
• intertroch fracture

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

• falsely decrease offset
• create valgus appearing femoral neck
• falsely decrease femoral canal diameter

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

double density appearance

• T1: dark (low intensity band)
• T2: focal brightness (marrow edema)

• bisposphonates/ aspirin
• core decompression +/ - bone graft
• rotational osteotomy 
• vascularized fibular bone graft

THA

• 1- proximal to femur component
• 2-component and moves proximally
• 3-distal to upper edge of anterior flange

may cause more posterior start point and therefore extension of femur

• 1-fracture tibial plateau
• 2-fracture adjacent to ste
• 3- distal to stem
• 4- tibial tubercle

• 88 tha
• 240 tka

• MMP
• tissue inhibitor MMP 
• IL-1, Il-6, TNf-alpha

if less than 8mm

( measure from bottom of metal tray)

more resistant to abbrasive and adhesive wear

• coxa vara ( increased fracture)
• LLD
• female sex child bearing age ( metal ions)
• renal failure

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

move acetabular component medial inferior and anterior

• femur:
• increase offset  
• long stem prosthesis
• lateralize greater troch
• varus neck

cane contralateral hand

longer leg

• 60 ml levobuipvicaine 2.5%
• 30 mg ketorlac
• 0.5 mg adrenaline
• 40 ml NS

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

• 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

• ROM <80 degrees
• obese patient
• hypertrophic arthritis
• previous HTO

• 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

• 1- osteophyte
• 2-posterolateral capsule
• 3-iliotibial band ( if tight in extension)
• 4-popliteus ( if tight in flexion)
• 5-LCL

• 1-osteophyte
• 2-posterior capsule
• 3-additional femur resection
• 4-gastrocnemius muscle
• ( done at 90 flexion)

• proximal tibia osteotomy opening wedge
• tibia tubercle slide/ transfer
• proximal tibia trauma
• elevate joint line tka
• acl recon

less than 0.8 is patella baja

patella bone articualr surface length/ patellar tendon

• lower joint line( augment for distal femur, cute more tibia)
• repalce patella and put puck more proximal

tibia tubercle transfer

• see on quas tendon and anterior femur hypertrophic arthrosis
• male gender
• obesity
• notching
• periosteal injury/ stripping
• post op knee effusion
• post op forced manipulation

• 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

• 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

medial gastrocnemius rotational flap (medial sural artery): anterior and medial defects

ateral gastrocnemius rotational flap (lateral sural artery): lateral defects

• reduces efficiency of gate by 50%
• 30% more oxygen expenditure

• 20-35° of flexion
• 0°-5° adduction
• 5-10° external rotation

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

• 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