Hip and knee board review

Richard Crank DO, FAOA

Lakeland Regional Health

No disclosures

Resources

Miller review

AAOS comprehensive review

Femoral Acetabular Impingement

Alpha angle

>42º=FAI

Center edge angle

<25º abnormal

Tonnis Angle

0-10º normal

FAI

Cam

Incidence 50% in athletes

Pincer

OA occurs by contact of labrum and bone and leads to cartilage delamination

Evaluate FAI- order an xray

Look for coxa profunda-floor is medial to ilioischial line

Protrusio-head is medial to ilioischial line

Cross over sign=retroversion acetabulum

TX FAI:

<35, activity modification, NSAIDs, INJ

NEVER REMOVE the labrum: detach and fix

POOR outcome: older age female, low BMI, full thickness cartilage defect

DDH

DDH

Issue of undercoverage and labral pathology

Associated with early OA

NEVER REMOVE THE Labrum

TX:

<35, No OA, normal round head, restoration of acetabular coverage on maximum abduction xray, preservation of joint space

Bernese Periacetabular osteotomy-Ganz:

Bernese Periacetabular osteotomy-Ganz: improves acetabular coverage

Abducts acetabulum, medialization of hip center, retroversion of the socket, LEAVES INTACT posterior column

IT IS OK for vaginal child birth after

THA:

Prepare for anteverted femur, small acetabulum, acetabular bone defects (ant/sup and sup/lat), posterior trochanter, small femoral canal

PLACE socket in true acetabulum, not high

Correct femoral version

Femoral shortening osteotomy

Corrects version, corrects trochanter position, protects sciatic nerve from lengthening

Ostenecrosis

ON

Crescent sign=impending collapse

Look at the other hip

MRI most sensitive test

Tx depends on age, underlying diagnosis, extent of ON

IF combined alpha angle on coronal and sagittal xray >200 THEN POOR outcome if non-arthroplasty treatment

If collapse >2mm, poor outcome with non-arthroplasty

If acetabulum involved=DUE arthroplasty

PRECOLLAPSE Tx:

Core decompression with/without bone graft

Postcollapse: THA no matter what age

TRANSIENT Osteoporosis of the

femur

DDX for ON

Transient osteoporosis of the femur

Typical question: 37y/o female

with 3 month hx of severe hip pain

Workup:

Oder the MRI, it will differentiate

from ON

Most common

Women 3rd trimester

Males 5-6 decade

TX: NON SURGICAL

OA

Arthroplasty: be conservative

Severe intractable pain for more

than 3 months

Wt loss, activity modification,

NSAIDs,

Steriod injection within 3-6 months

of surgery increases risk for

infection

FUSION of the hip

Incidence is most common for

exam answer

Most appropriate for septic hip

30º flexion, 0-5º ER, 0-10º ABD

APPROACHES

DA: learning curve

Interval: Sartorius/TFL

Danger: LFCN, LF circumflex art

POST:

Interval: glut max/med, TFL

Danger: sciatic nerve

Higher dislocation

REDUCE by: POST CAPSULAR

REPAIR, larger head

Watson-Jones:

Interval: TFL/Glut med

Danger: femoral nerve, Sup glut

nerve, LF circumflex art

Direct lateral:

Interval: glut med/vast lateralis

Danger: sup glut nerve

PROLONGED LIMP

Acetabular component

USE UNCEMENTED

Failure is due to poly wear and

osteolysis in CONVENTIONAL poly

POSITION:

40/20

Safe zone for screws

POST/SUP and POST/INF

KNOW structures in zone of injury

Femoral Component

Cemented have good outcome

and survivorship

Any pre-coated stem worse

survivorship with cement

Uncemented

Tapered or diaphyseal both good

Trunionosis: think about problem

with titanium stem and

cobalt/chrome head

Modular Neck:

Better control version, offset, length

Problems: fracture, fretting,

corrosion

Polyethylene

Highly cross linked= decrease

wear and lysis

Vitamin E might decrease

osteolysis ?? Cost effective

POSITION OF COMPONENTS IS

IMPORTANT

Vertical is bad= higher wear

Re-melting: REMOVES free

radicals; REDUCES mechanical

properties

Annealing: LEAVES free radicals;

MAINTAINS mechanical properties

Other bearings

Ceramic- decrease wear ?? Cost

MOM- higher failure than other bearing option

Larger head with MOM THA=higher failure

Higher revision in older patient

w/u painful MOM hip: NORMAL w/u first (infection, loosening)

Ions: They will give very high numbers in the question

Advanced imaging: U/S, MARS

Pseudotumor: LYMPHOCYTE, PLASMA CELL

OTHER HOT HIP TOPICS Readmission 3.5-5.5% 30 day, 7% day

Risk factors fair game

Length of stay, SNF, gen anesthesia, blood transfusion

Intraoperative fracture: cable and stable; DO NOT change post op rehab protocol

LINER EXCHANGE only for well fixed, well positioned components with a GOOD tract record

Iliopsoas tendonitis:

Cause: large head, cup protrusion

Tx: conservative

Revise mal-positioned components

Tenotomy ONLY if good position components

HO:

NSAIDs are ONLY for prophylaxis

If treating HO: excision and single dose radiation

Hip resurfacing

“Bone Conserving”

More acetabular bone loss, less

femoral bone loss

PROBLEMS:

MOM problems

Femoral neck fracture

High revision in women and

younger patients

INVERSE relationship between

head size and revision

Bigger heads better (NOT TRUE FOR

MOM THA)

Revision hip

REVISE MALPOSITIONED

COMPONENTS ON TEST

Look at leg length, impingement,

offset

DUAL MOBILITY: it decreases

instability for those RESIVED for

instability

Problem: intra-prosthetic

dislocation

CONSTRAINED liner only if

DEFICIENT abductor AND well

positioned components

Paprosky acetabular

I -hemispherical shell

IIa –

column intact: hemispherical shell

>50% uncovered augment to bring

cup down

IIb – sup lysis, up and out; sup/lat

Column intact: metal augment,

jumbo cup, high hip center

placement

IIc – medial defect; tear drop

gone, ischium intact

Hemispherical cup, RARE cage

IIIa – UP UP/ out; >3cm up, ischial

lysis

Augment, cup, cup/cage

IIIb – BAD; UP UP/in;

DISCONTINUTIY

Cage, triphlange, multiple

augments

Paprosky

Paprosky femoral

I – regular stem

II – metaphyseal loss

Fully porous coated or tapered Wagner

IIIa – metadiaphyseal loss

same stem

IIIb - <4cm scratch fit

Wagner, fully porous coated, PFR, Allograft composite

IV – massive loss

Impaction grafting, PFR, allograft

Vancouver classification

Vancouver classification

A- treat osteolysis

B1- well fixed stem, protection/ stabilize

B2,3 – revise

C - ORIF

Knee OA

Wt loss, activity modification, inj

SCOPE is NOT answer for test

Osteotomy

<60, single compartment, good

motion, NO flexion contracture,

NO inflammatory

Closing: need fibular osteotomy,

LOSS post slope

Opening: higher nonunion rate,

slope maintained

UKA

Lower long term survivorship in

most cases compared tka

Lower short term complications

compared to tka

Singe compartment disease only

never inflammatory

Failure: loosening, OA progression,

PF instability

TKA

Cemented survivorship better than

uncemented

All other outcomes same, CR, PS,

patella resurface or not

There is a higher risk of revision with

patellar resurfacing

If you revise for pain to resurface

the patella ONLY 50% get better

Gap balance

Coronal balancing

Osteophytes

Varus deformity: Medial release

Deep MCL

Post medial corner with

semimembranosus

Pes

PCL

Valgus deformity: lateral release

Osteophytes

IT band if tight in extension

Popliteus if tight in flexion

LCL

RELEASE THE CONCAVE side

tka

CAS increased outliers

Patient specific blocks decrease in

outliers

If cut MCL, INCREASE constraint

and repair

Patellar tracking: ER femur, ER

tibia, lateralize femoral

component, medialize patellar

component

Extensor mechanism disruption:

Acute: repair and augment with

hamstring autograft

Chronic: allograft/mesh THEY ALL

DO BAD, infection, lag

Arthrofibrosis: MUA < 12 weeks

Patellar clunk: occurs 45-30º flexion

ARTHROSCOPIC DEBRIDEMENT

tka

Nerve injury most common with

valgus knee and flexion

contracture

Peroneal nerve

Tx: remove dressing and flex knee

Popliteal artery is posterolateral to

PCL

Dx EARLY

Dx late: poor outcome

Patella fracture

Conservative tx do best

UNLESS: implant loose or ext mech

disruption, must fix POOR outcome

Knee revision

BMI >40:

decreased survivorship, increased

lucent lines, higher failure

Decreased functional scores but

have a higher delta

R/O hip cause for painful TKA

Causes: aseptic loosening,

instability, infection

POLY change is NEVER the answer

(unless says “what not to do”)

Stem fixation: hybrid stems must

engage diaphysis otherwise high

failure

Can retain patella if not oxidized,

well positioned, well fixed

Knee revision

Periprosthetic fracture:

Know the bone quality

Frx displacement

Implant stable

Fix vs revise

Infection

Major criteria

Sinus tract

2 positive cultures

Alpha defensin

High sensitivity/specificity

Adjunct only

UKA numbers

ESR 25

CRP 17

WBC 6500

PMN 72%

infection

Risks: malnutrition, smoking,

uncontrolled DM, BMI > 40

MRSA screening decreases

incidence of infection

Antibiotics preop

Ancef or Clinda < 1 hour

Vanc - 2 hours before

ONLY FOR: MRSA carrier, region

with high MRSA, institutionalized,

health care workers

MOM must have manual cell

count because machine will count

particles

Wound drainage for 5-7 days:

Get labs

Aspirate

Washout deep space: open fascia

Due I&D early: < 3 weeks from

surgery or acute hematogenous

infection

1 stage:

Must know organism

No soft tissue deficit; sinus tract

Not a poor host

Not for resistant organism

2 stage: gold standard

Infection

Early: staph

Late: staph epi, strep veridans, P.

Acne

Other points

Tranexemic acid decreases blood

loss: all forms (oral, iv, topical)

VTE prophylaxis

Healthy: ASA

Everyone else with risk factors:

something stronger

SCD for everyone in perioperative

period

GOOD LUCK