Total Knee Tips & Pearls From Dr. Adam Rosen (A Virtual Total Knee Fellowship Podcast)

Changes in Trabecular Pattern of the Upper End of the Femur as an Index of Osteoporosis
Manmohan Singh et al
JBJS 1970

Grade 6 - All normal trabeculae are visible
Grade 5 - accentuation of the principal compressive and principal tensile trabeculae
          - Ward's triangle looks empty
Grade 4 - tensile trabeculae are reduced
          - Ward's triangle opens up laterally
          - border line between osteoporotic and normal bone
Grade 3 - break in the continuity of the priciple tensile group
          - definite osteoporosis
Grade 2 - principal compressive trabeculae are the only prominent trabeculae
Grade 1 - all trabeculae are reduced

The Normal Trabecular Pattern
1. Principal compressive group
2. Secondary compressive group
3. Greater trochanter group
4. Principal tensile group
5. Secondary tensile group

Wards Triangle (first described 1838)
An area in the neck between the principal compressive, secondary compressive and primary tensile group

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Total Hip Replacement in Congenital Dislocation and Dysplasia of the Hip
John Crowe, John Mani, Chitranjan Ranawat
JBJS 1979

I - < 50% subluxation
II - 50% - 75% subluxation
III - 75% - 100% subluxation
IV - >100% subluxation

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The International Consensus Meeting on MSK Infection presented their new criteria in 2018

Major Criteria
1. Two positive periprosthetic cultures w/ phenotypically identical organisms
2. A sinus tract communicating with the joint
____________________
Minor Criteria
> or equal to 6 = infected
4-5 = inconclusive
< or equal to 3 = not infected
___________________
2 points for:
Serum CRP 100 in acute or 10 in chronic
or
D-dimer 860 in chronic

1 point for:
ESR 30 in chronic

3 points for:
synovial WBC 10,000 in acute or 3,000 in chronic
or
leuk esterase ++ in acute and ++ in chronic
or
positive alpha defensin
2 points for:
synovial PMN 90 in acute or 70 in chronic

2 points for:
single positive culture

3  points for:
positive histology

3 points for:
intraoperative purulence

ICM Philly website: https://icmphilly.com/

PJI Risk Calculator:  https://icmphilly.com/ortho-applications/prosthetic-joint-infection-pji-risk-calculator/

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Kellgren, Lawrence. Radiological Assessment of Osteoarthritis. Ann Rheum Dis. 1957;16:494-502

Grade 0 - No presence of OA
Grade 1 - Doubtful narrowing, possible osteophytes
Grade 2 - Possible narrowing, definite osteophytes
Grade 3 - Definite narrowing, moderate osteophytes, some sclerosis and possible deformity
Grade 4 - severe narrowing, large osteophytes, marked sclerosis, definite deformity

X-rays finding of OA
narrowing of joint space
osteophytes
sclerosis of subchondral bone
pseudocystic changes
altered shape

Interesting short biography on Dr. Kellgren:
https://academic.oup.com/rheumatology/article/42/5/708/1784848

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Paprosky Classification of Femoral Bone Loss

Type I - minimal metaphyseal bone loss
Type II - extensive metaphyseal bone loss, minimal diaphyseal bone loss
Type IIIA - extensive metaphyseal and diaphyseal bone loss with greater or equal to 4 cm intact diaphysis for "scratch fit"
Type IIIB - extensive metaphyseal and diaphyseal bone loss with less than 4 cm of intact diaphysis
Type IV - extensive metaphyseal and diaphyseal bone loss with a non-supportive isthmus

Treatments
I - cylindrical fully porous coated stem (consider tapered proximal geometry or cemented stem)
II - diaphyseal engaging stem
IIIA - diaphyseal engaging stem (impaction grafting, modular stems)
IIIB - tapered stem with splines for rotational stability (impaction grafting, modular stems, PFR)
IV - PFR, impaction grafting with cemented stem, allografts

Aribindi, Barba, Solomon, Arp, Paprosky. Bypass fixation. Orthop Clin North AM. 1998;29:319.
Paprosky, Aribindi. Hip Replacement: treatment of femoral bone loss using distal bypass fixation. ICL 2000;49:119-130.
Della Valle, Paprosky. The femur in revision total hip arthroplasty evaluation and classification. CORR 2004;420:55-62.
Cross, Paprosky. Managing femoral bone loss in revision total hip replacement: fluted tapered modular stems. Bone Joint J. 2013;95 (11 supp A):95-97.

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"Modes of Failure" of Cemented Stem-type Femoral Components
Gruen, McNeice and Amstutz
CORR 1979

Seven Gruen zones

1 - proximal lateral 1/3
2 - central lateral 1/3
3 - distal lateral 1/3
4 - tip
5 - distal medial 1/3
6 - central medial 1/3
7 - proximal medial 1/3

Modes of Failure

I. Pistoning
     Ia. stem pistons in cement (punch-out crack)
     Ib. cement pistons in bone (halo)

II. Medial Midstem Pivot - medial migration of proximal stem, lateral migration of tip

III. Calcar Pivot - medial-lateral toggle of tip (windshield)

IV. Cantilever Bending - loss of proximal support, tip is fixed

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I just wanted to share my thoughts and give you my two cents on where we may be in ten years. We still have 20% of patients that are dissatisfied after TKA. WHY?
We get answers from industry - nav and robots?
But, what is the question?
Listen in to hear my thoughts on AR and AI and how a heads up display could help you decide how to best perform a TKA to get satisfaction rates up to 95% or higher.

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Low-Angle Fixation in Fractures of the Femoral Neck
Garden JBJS-B 1961

Stage I - Incomplete and abducted or valgus impacted
Stage II - Complete and non-displaced
Stage III - Complete partially displaced
Stage IV - Complete fully displaced

Pauwels Classification 1935

I - up to 30 degrees
II - 30 - 50 degrees
III - greater than 50 degrees

a line drawn thru the fracture on the AP x-ray in relation to a line from the horizontal

Bonus credit - look up Wards Triangle first described in 1838

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AORI Classification

Type 1 - Minimal bone defect, intact metaphysis
     - Treat with cement or impaction grafting

Type 2A - Metaphyseal bone damage of 1 femoral condyle (F2A) or 1 half of the tibial plateau (T2A); posterior condyles are reduced
     - Treat with cement, augments, bone graft, cones/sleeves

Type 2B - Metaphyseal bone damage of bone femoral condyles (F2B) or both sides of the plateau (T2B)
     - Treat with cement, augments, bone graft, cones/sleeves

Type 3 - Massive bone loss of large portion of the condyles and/or plateaus; can involve the collaterals and/or patellar tendon
     - Treat with allograft, custom implants, sleeves/cones/augments, hinge, DFR

A Classification of Bone Defects, In: Revision Knee Arthroplasty. 1997 p 63-120

Engh and Ammeen
1. Classification and Pre-operative Radiographic Evaluation. Ortho Clinics N. Amer 1998 Apr; 29(2) 205-17.
2. Classification and Alternative for Reconstruction. ICL 1999, 48: 167-175.

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Dorr Classification; Bone 1993

"Structural and Cellular Assessment of Bone Quality of Proximal Femur"

A - Thick cortex - champagne flute canal

B - Thin cortex with residual funnel shape

C - Thin cortex - "stove pipe canal"

Canal/Canal Ratio
A - <0.5
B - 0.5 - 0.75
C - >0.75

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