tka

Here I share with some some tips and tricks on what I look for and what I do when caring for the 50 and older patient with knee pain that does not have severe arthritis and does have a meniscus tear.

I also share some tips on what to do during boards collections to make sure you have copies of the intra-op photos and how I discuss the surgical findings with my patients in the office.

Know if it is fixed or correctable
Assess the amount of osteophytes
Release MCL around to semimembranous
Assess PCL if using CR
Consider downsizing tibial and removing additional medial bone

Further Reading:

Master Techniques Knee Arthroplasty - Lotke and Lonner
Chapter 7 by Scuderi and Insall

Advanced Reconstruction of the Knee AAOS
Chapter 27 - Varus Knee - Windsor and Choi

JAAOS Article Dr. Mihalko -  http://upload.orthobullets.com/journalclub/free_pdf/19948701_19948701.pdf

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Its good to have an algorithm that works for you when describing an x-ray. Here I will go through my thought process to make sure that you cover everything and not miss things.

The kinematics of the knee are so complex. You can not overlook the PFJ. We are taught early on about medializing the button and lateralize the femur and make sure your femoral rotation is correct. If not you are taught to do a lateral release.

The balancing of the PFJ is so important. Overstuff it and you have pain and limited range of motion.  Too loose and you lose efficiency of the extensor mechanism.

Here I will share some tips and my thoughts on what I look for when I do a TKA specifically focusing on the PFJ.

Roentgenographic Analysis of Patellofemoral Congruence

Alan Merchant, Richard Mercer, Richard Jacobsen, Charles Cool

JBJS 1974

Merchant View - patient is supine on the x-ray table. The knees are flexed 45 degrees and the legs are strapped. The beam to femur angle is 30 degrees and the plate is positioned against the shins.

Sulcus Angle of Brattstrom - angle formed by the highest points on the medial and lateral femoral condyles and the lowest point of the sulcus

Congruence Angle - sulcus angle is bisected to establish the reference line. Another line is drawn from the apex of the sulcus to the lowest point on the patellar articular surface.

The Forty-five-Degree Posteroanterior Flexion Weight-Bearing Radiograph of the Knee

Thomas Rosenberg, Lonnie Paulos, Richard Parker, David Coward, Steven Scott

JBJS 1988

PA x-ray with the knee in 45 degrees of flexion and the patella touching the cassette. The beam is aimed at the inferior pole of the patella and aimed 10 degrees caudad,

55 patients in 1981-1982 (age 19-70)

Major narrowing in the medial compartment
AP xray - 25%
Rosenberg - 85%
Major narrowing in the lateral compartment
AP xray - 30%
Rosenberg - 80%

Additional advantage of identifying osteophytes in the notch, loose bodies, OCD and SONK

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

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

"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

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

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.

Vancouver Classification by Duncan and Masri ICL 1995
Treatment options added in CORR 2004

Type A

AL - lesser trochanter - non-op unless larger medial piece
AG - greater trochanter - non-op unless >2.5 cm displacement

Type B

B1 - well fixed stem - ORIF
B2 - loose stem, adequate bone stock - revision w/ ORIF
B3 - loose stem poor bone stock - revision w/ allograft or PFR

Type C

C - fracture below the tip of the stem - ORIF

In my first year of practice I remember a day where I only had three joints but it took all day and I was exhausted.  Although they were all primaries they each had a component that made them hard - size, bone loss, stiffness.

I created a system that allowed me to communicate with my scheduler so they could spread out the hard cases which prevented one day from having all chip shot easy cases and another day which had all of the hard cases.

I hope you find this tip helpful in your practice.

Ortho is consulted for many things.  Here I would like to go over a few topics.

First, for most ortho consults we need an x-ray.  For a fracture or dislocation it is imperative.  Even without trauma a bone can break if it had an un-diagnosed tumor.  Even when the xray is normal, the information is important.

I will discuss compartment syndrome, cellulitis, dog bites, and more.  I also cover some classic knee jerk reactions in post-operative patients such as when to and when not to pan-culture and order CT's and US.

It looks like things will be virtual for now.  I am going to offer my thoughts on what I was looking for when I applied for a fellowship.  I'll review things I think are important such as number and type of cases, office hours and education.  Briefly, I touch on things I discuss as an overview of the fellowship I am involved in.  Disclaimer: I work where I did my fellowship so there may be some bias.

After medical school, residency and probably fellowship it is time to find a practice.  Here I will try to offer my two cents on what to think about and what to look for when you start looking for that first job out of training.

Everything is a series of steps.  Once you have performed the approach and the implant removal it is time to prepare the bone.

You can do this in many ways. I typically start with the tibia then move to the femur.  Performing the distal femur and tibia cut and knowing my extension gap helps me size and position the femur.  Knowing what size component and the size of the augments and potentially the need to offset helps balance the flexion gap with the extension gap.

Revisions are hard.  They may be for one component or all components.  It may be for laxity, stiffness, poly wear, aseptic loosening, infection or fracture.  In any event they can be difficult.

Here I will talk through my approach to the exposure and how I remove the femoral and tibial components.

In the next episode I will go into bone cuts, sizing, rotation and the joint line.

I came from Philadelphia where I only saw PS knees.  I was told CR knees were hard to expose and hard to balance.  When I went west for my fellowship I saw predominantly CR knees.  In practice I perform CR knees for 95% of my primary TKAs.  I will share with you some of my thoughts and tips.