Arthroplasty - Orthobullets

• Reduced by 50%
• 30% more energy expenditure

• 20 flexion
• 0-5 addcution
• 5-10 ER

• Active infection
• Severe LLD
• Bilateral LLD
• Adjecent joint degeneration
• Contralateral THA

• Back pain: most common
• Ipsilateral knee pain and instability
• Contralateral hip pain

Abductor function with EMG >>may need constrained cup

• Retained cement
• Malpositioned cup
• LLD
• Excessive lenght of screwzs

• Resisted hip flexion or straight leg raise
• 8mm of anterior overhang

• Hypertrophic arthritis
• male
• obesity
• notching femur
• Periosteal strippinf of anterior femur
• post op hematoma
• post op MUA

• Class 1: suprapatellar soft tissues bony island
• Class 2: continuous with anterior distal femur

• Grade A: <5cm
• Grade B: >5cm

• Infection
• Overstuffing/maltracking: leads to increased shear forces

• Nickel found on cobalt chromium alloys
• Type IV: mediated by T cells

• Bone graft
• Metal wedges/comes

• Medial gastrocs flap: medial sural artery
• Lateral gastrocs flap: Lateral sural artery

• Lateral: posterior to the posterior horn of the lateral meniscus
• Adductor hiatus of adductor magnus
• Soleus tendon

• Middle genicular A
• Medial sural A
• Lateral sural A

• Lateral genicular A
• Medial Genicular A

Increased rate of transfusion

MMP: matrix metalloproteases

• Tramadol/NSAID's
• In contralateral side: reduces joint reactive forces

• 5-7 degrees
• 2-3 degrees

• Restore mechanical alignment
• Restore joint line
• Balance ligamnets
• Maintain normal q angle: for patellar tracking

• Avoid excessive IR femoral component
• Avoid medialization femoral component
• Avoid IR tibial component
• Avoid medial positioning of patellar component

• Mid flexion instability
• PF tracking problems (patella baja)

• Lack full extension
• Flexion intability

• 3-4 weeks after R THA
• Reaction time returns to preop levels at 4-56 weeks

Operative leg lengthening most common

• Middle aged men
• Women in third trimester of pregnancy
• Resolves within 6-8 months
• Diffuse osteopenia t head neck: appears 4-6 weeks after symptoms
• Diffuse edema but no focal defects or subchondral changes
• Treatment: protected weight bearing

• PS TKA
• Scar formation in posterior aspect of proximal patellar pole >>>catches on the box
• Arthroscopic debridement if symptomatic

Patella ok: primary repair + allograft/autograft augmentation

Patella not ok: extensor mechanism allograft

Opioids: Mu agonist > neuron hyperpolarization and reduced excitability

NSAID: Inhibit COX1 and COX 2 >>>inhibit inflammation 

Selective COX-2 inhibitors >>inhibit transformation of AA to PG >>>>mininmize GI side effects, may inhibit bone healing

Gabapentin/pregabalin: reduce hyper-excitability of voltage dependent Ca2 channels in activated neurons

• 95
• 105
• 65

• Cement
• Bone ingrowth: highly porous
• Bone ongrowth: grit blasted/plasma sprayed

1st Gen

• hand mixed
• Finger packed
• No canal preparation

• 2nd Gen
• Cement restrictor
• Cement gun
• Femoral canal preparation with brush

• 3rd gen
• Vacum mixing
• cement pressurization
• Femoral canal preparation with jet lavage

• Limit porosity of the cement: 3rd generation mixing technique
• Cement mantle >2mm: increased risk of fracture if mantle < 2mm
• Stiff femoral stem
• Stem centralization
• Smooth femoral stem
• Absence of cement mantle defects
• No varus or valgus malalignment

• Pore size 50-300 micrometers
• Porosity 40-50%
• Gaps <50 micrometers
• Micromotion <150 micrometers: more micromotion leads to fibrous ingrowth

• Osteoconductive agent that allows more rapid closing of gaps btw bone and prosthesis
• Decreased time to ingrowth
• No difference

• Spot welds
• Absence of radiolucent lines around porous part of stem
• Proximal stress shielding if extensively porous coated
• Absence of stem subsidence on serial radiographs

• Deep MCL to midcoronal plane
• Osteophyste removal
• Rlease Posteromedial corner: posterior oblique ligament
• Medial tibial reduction osteotomy
• PCL release
• Release Semi membranosus: especially if flexion contracture
• Pie crust MCL

• Osteophyte
• Posterolateral capsule
• IT band: if tight in extension
• POpliteus: if tight in flexion
• LCL: IF tight in flexion and extension

Line from ASIS to center acetabulum and a second line perpendicular through it

Postero superior: Safe zone >>iseal spot for screw placement

Posteo inferior: If > 20 mm sciatic nerve/inf gluteal nerve and vessels at risk

Antero superior: Danger zone >>obturator nerve artery and vein

Antero inferior: death zone >>external iliac vessels at risk

• Decrease
• Decrease
• Decrease
• Increase
• Decrease: decreases abductor pull
• Decrease: leads to trendelenburg gait

Choose the most lateral bc blood supply comes from medial side

Quads snip: snip at the apex of quads tendon oblique at 45 degrees into vastus lateralis

V-Y turndown: Medial parapatellar approach with a second incision leading for the vastus lateralis towards lateral retinaculum

TT osteotomy

shown to reduce rates of infection in revision TKA

• Connective tissue disorders
• Inflammatory disease
• Diabetes or charcot arthropathy

• Use unlinked constrained prosthesis
• Repair and place in hinged knee brace for 6 weeks

Increases lever arm of extensor mechanism

• MPFL: at 20 degrees of flexion
• Medial patellomeniscal ligament
• Lateral retinaculum

As the knee flexes the COR moves posteriorly as the femur rolls back >>allows for increased knee flexion by avoiding impingement

Tibia ER 5 degrees in the last 15 degrees of extension > locks the knee: Due to the fact that the medial plateau is longer than lateral plateau

• Pre op ROM: most important
• Patella baja
• Increased comorbidities
• Low pain tolerance

12 weeks: risk of fracture and extensor mechanism disruption

• Pre op valgus or fixed flexion deformity
• Tourniquet time >120 min
• Post op use of epidural analgesia
• Aberrant retractor position
• Pre-op neuropathy

50% recover wit no additional rx

• Remove dressing and place knee in flexion
• AFO
• Nerve transfer or decompression: no recovery after 3 months ...use tib post transfer tolateral cuneiform

• Steep learning curve: complication rate decrease after 100 procedures
• SSI increased in obese patients
• Challenging femoral exposure
• LFCN palsy
• Intra op # may be higher

• Lateral x ray
• Use insall salvati ratio: if <0.8 its baja
• Its ratio of patellar tendon lenght to patellar bone lenght

• Medial opening wedge
• Elevation of the joint line from excessive distal femoral cut

• Grade 1
• Proximal displacement <10% of pelvis height
• Proximal migration of head neck from teardrop junction <50% of femoral head vertical diameter

• Grade 2
• 10-15%
• 50-75%

• Grade 3
• 15-20%
• 75-100%

• Grade 4
• >20%
• >100%

Type A: Dysplasia>>>head in acetabulum with some dysplasia

Type B: Low dislocation>>> false acetabulum superior to true acetabulum

Type 3: High dislocation

• < 20 degrees
• >10 degrees

3.5 cm or 10% of the length of femur

• 87%
• Overcorrect to 10 degrees of valgus

• Inflammatory arthritis
• BMI >35
• flexion contracture >15 degrees
• Knee flexio <90
• >20 degrees of correction
• PF OA
• Ligament instabilit
• Varus thrust

Periprosthetic neck #

• DDH
• Revision surgery
• Female
• Limb lengthening
• Post traumatic
• Surgeon reported as difficult procedure

• Remove compressive bandages
• Place hip in extension with knee flexed
• Assess for hematoma
• Prescribe AFO
• Shorten if excessive lengthening

• 15 degrees anteversion
• 40 degrees abduction

Combined version: 37 degrees

10-15 degrees of anteversion

• NSAID's
• Exercise, education, wellness
• Weight loss

• Acupuncture
• Viscoelastic joint injection
• Glucosamine
• Needle lavage
• Lateral wedge insoles

Medial femoral condyle

SU

Type 1: # line proximal to femoral component

Type 2: # line originates at proximal end of component

Type 3: # line distal to anterior flange of femoral component

Felix

Type 1: tibial plateau

Type 2: Adjacent to tibial stem

Type 3: distal to tibial component

Type 4: tibial tubercle #

Aseptic loosening: tibial more common than femoral

Followed by Infection, instability, fracture

1.5-2cm above head of fibula

• Cement if small, may need allograft
• Metaphyseal sleeves

Whiteside line: draw line perpendicular to it

Transepicondylar axis: cut parallel to this

Posterior condylar axis: normal is 3 degrees of internal rotation >>need to ER femoral component 3 degrees

Center it over medial third of the tibial tubercle

• Inflammatory arthritis
• Patella maltracking
• PF arthitis as the main indicatior for TKA

• Faster rehab and quicker recovery
• Less blood loss
• Less morbidity
• Less expensive
• Preserves normal knee kinematic
• Smaller incision: less pain

• Inflammatory arthritis
• ACL deficiency
• Fixed varus > 10 degrees
• FIxed valgus > 5 degrees
• Flexion < 90
• Flexion contracture > 5-10
• Tricompartmental OA
• Young active patient
• Overweight

• Undercorrect by 2-3 degrees: avoid stressing other compartment
• 93% at 15 years

• Radiation
• Trauma
• Hematologic: leukemia/lymphoma
• Caissons
• Gaucher
• Sickle cell
• ETOH
• hypercoagulble
• Steroids
• SLE
• Virus: HIV/hepatitis
• Idiopathic

Kerboul angle

Low risk: combined AP and lateral <190

Mod risk: combined 190-240

High risk: combined > 240

• Stage 0: normal x ray and MRI
• Stage 1: normal x ray abnormal MRI

• Stage 2: cystic or sclerotic changes
• Stage 3: Crescent sign
• Stage 4: flattening of femoral head
• Stage 5: narrowing joint
• Stage 6: Advanced degenerative changes

Bisphosphonates: precollapse FICAT 0-2

Lightbulb: through cortex of femoral head neck junction

Mont trap door: through articular surface

Lateral femoral circumflex

Sensory deficit

• Motor weakness
• FHL contracture
• Tibial stress fracture

• Extension gap
• Flexion gap: increasing size of femoral component only changes flexion gap
• Both gaps

• Did not cut enough tibia: cut more tibia
• Did not cut enough posterior femur: decrease femoral component size (will need more resection
• Did not cut enough distal femur: cut distal femur
• Cut too much distal femur: augment distal femur
• Cut too much tibia: use bigger poly or metal augments

<8mm

If during sterilization (radiation)

2 or more indications and evidence of implant malalignment, implant failure or poly wear

• Age >70
• Female gender
• AVN
• Inflammatory arthritis

From paper from mayo

Paprosky

Type 1: minimal deformity, intact 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 to 2pm around rim, superolateral cup migration

Type 3B: Bone loss from 9AM to 5pm, superomedial cup migration

Paprosky

Type 1: minimal metaphyseal bone loss >>Primary THA

Type 2: Extensive metaphyseal bone loss with intact diaphysis >>>extensive porous coated long stem

Type 3A: Extensive metadiaphyseal bone loss, minimum of 4 cm intact bone>>>>>extensive porous coated long stem

Type 3B: Extensive metadiaphyseal boe loss, less than 4 cm of intact bone in diaphysis>>> impaction allograft/APC/Oncology stem

Type 4: Extensive metadiaphyseal bone loss and a non supportive diaphysis>>>>>  impaction allograft/APC/Oncology stem

Component loosening

• Prolonged surgical time
• Excessive soft tissue handling
• Hypertrophic arthritis
• Male gender

Indomethacin 75mg qd x 14-42 dys

600-800cGy within 48 hrs of procedure

Radiostereometric analysis

Adhesive: Polyethelene  sticks to prosthesis and debris gets pulled off

Abrasive wear: cheese grater effect of prosthesis scraping off particles

Third body: loose bodies in joint scraping off particles

Volumetric wear: related to the square of the radius of the head

Wear particles >  macrophage activation  > release of osteolytic factors >>>TNF alpha >>> RANKL activation

Type A: GT#..usually associated with osteolysis..Treat non op if displaced <2cm...ORIF is displaced >2cm

Type B1: fracture around or just below stem with stable implant>>>>ORIF

Type B2: Fracture around stem or just below with unstable implant but good bone stock>>>revision with wagner and cerclage wires

Type B3: Fracture around stem or just below with unstable implant but poor bone stock>>> Allograft or tumor prosthesis

Type C: Fracture well below prosthesis >>>>ORID with plate

Within 3-6 weeks from surgery

Major

• Sinus tract communicating with prosthesis
• Pathogen isolated by culture from 2 separate tissue/fluid samples

Minor

• Elevated ESR >30 or CRP>10
• Elevated WBC: >1100 knee, >3000 hip
• Elevated PMN: >64% for knee, > 80% for hip)
• Purulence of affected joint
• Pathogen isolation of one culture
• > 5 PMN per hpf in 5 HPF at 400X

40g bag = 3g of vanco and 4g of tobramycin