RECON

Question 1

Indication for distal femur varus osteotomy include:

Answer 1

1) at least 12-15 degree valgus mechanical axis
2) ROM of at least 15-90 degrees

Contraindications: inflammatory arthritis and/or restricted knee ROM

Question 2

What is the most common complication following revision of failed metal-on-metal hip replacements?

Answer 2

INSTABILITY

– due to local tissue distruction and degradation of the hip abductor mechanism

Question 3

LIFT-OFF of the anterior portion of the trial insert during CR-TKA trial reduction suggests…

Answer 3

tight PCL

Question 4

Gap Balancing:

Medialization of the tibial tray on the tibia would result in _____

Answer 4

tighten the medial extension AND flexion gaps

Question 5

Does PCL resection affect gap balancing?

If so, how?

Answer 5

PCL resection increases FLEXION gap 2mm to 6mm more than the extension gap

– therefore posterior femoral balancing must be matched to avoid creating a mismatch

Question 6

If the patella is subluxating, during TKA trialing, you can ___MEDIALIZE or LATERALIZE__ the PATELLAR button to improve tracking?

Answer 6

MEDIALIZE the patellar button

Question 7

If the patella is subluxating, during TKA trialing, you can ___MEDIALIZE or LATERALIZE__ the FEMORAL component to improve tracking?

Answer 7

LATERALIZE the femoral component

Question 8

Describe the major changes involved with each Paprosky classification types (acetabulum).

Answer 8

Type 1 - near primary situation, >90% bone support for cup

Type 2 - Less than 3cm superior migration

2A - supero-medial

2B - supero-lateral

2C - medial defect with protrusio

Type 3 - More than 3cm superior migration

3A - “up & out”

3B - “up & in” (no medial or superior support) +/- pelvic discontinuity

Question 9

Alpha-defensin is a protein found in synovial fluid that is released by activated ____.

Answer 9

activated NEUTROPHILS

(ergo, a marker for PJI)

Question 11

What are the suggested implant choices for THA revision with acetabular component osteolysis?

Answer 11

IF rim is competent (Type 1 & 2): porous-coated hemispherical cup + screws

IF rim is incompetent: recon CAGE with bone allograft

IF pelvic discontinuity is present: custom TRIFLANGE

Question 12

A hypoplastic LFC can lead to __EXTERNAL or INTERNAL__ malrotation of the the femoral component if not recognized.

Answer 12

INTERNAL rotation (if using a posterior reference)

– therefore use AP axis to reference for valgus knee

Question 13

If the patella is subluxating, during TKA trialing, you can __INTERNALLY or EXTERNALLY___ rotate the TIBIAL component to improve tracking?

Answer 13

EXTERNALLY rotate the tibial component

Question 14

Why is it recommended to order a MANUAL cell count for a THA aspirate with metal on metal bearings?

Answer 14

tissue debris in suspension may lead to falsely elevated automated cell counts

Question 15

For UNIcompartmental arthritis, which is preferred:

CLOSING-wedge or OPENING-wedge osteotomy?

Answer 15

CLOSING-WEDGE osteotomy is preferred

– higher union, less pain, improved ROM, better satisfaction scores