MSC Week 5 Trauma/Shoulder UPDATED
ACTUAL Exam Questions and CORRECT
Answers
Principles of AO - CORRECT ANSWER - Anatomical reduction, Stable internal fixation,
preservation of blood supply, early mobilization
Fixation - CORRECT ANSWER - External fixation is a temporary solution for trauma.
Internal can be temporary or permanent. Helps fuse or heal fracture sites.
Principles of plate fixation - CORRECT ANSWER - The tension band. Conversion of
tensile forces to compression forces on the convex side of loaded bone. Screw generally should
not be placed less than 1 cm (10mm) from fracture line.
Device screw features - CORRECT ANSWER - Headed/Headless, Fully or partially
threaded, Self tapping or self drilling tip, Thread pitch is distance between threads.
Cancellous Screws - CORRECT ANSWER - Larger thread to cut through SOFT bone.
Large thread height and large thread pitch.
Corticol Screws - CORRECT ANSWER - Smaller threads because of hard corticol bone.
Short thread forms. Short thread height and a short thread pitch.
Hollow and solid screws - CORRECT ANSWER - Hollow provide guidance for k-wires.
Solid are stronger than hollow.
Cannulated screws - CORRECT ANSWER - Utilize a k-wire/guide pin. Typically self-
drilling and self-tapping. Both headed and headless types provide compression at the fracture
site. Length is determined by placing gauge over k-wire.
, Headless screws - CORRECT ANSWER - Both ends with threads, middle without.
Always cannulated.
Headed screws - CORRECT ANSWER - Certain proportion to shaft. Contacts bone to
outside.
Self-tapping screws - CORRECT ANSWER - Designed to cut pattern into bone.
Self-drilling screws - CORRECT ANSWER - No need to drill pathway.
Blunt tip screws - CORRECT ANSWER - Used for soft tissue protection.
Solid core screw - CORRECT ANSWER - Basic orthopedic screw; typically fully
threaded and self-tapping. Instruments used are bone forceps, drill guide, drill bit, depth gauge,
screw driver.
Screw and Drill bit sizing - CORRECT ANSWER - Screw sizing is the thread major
diameter and overall length. Principle drill replicates the minor thread diameter. Over drill bit
size corresponds to the major thread diameter. Allows fully threaded screw to be used as a
partially threaded screw when the near fragment is drilled.
Lag Screw - CORRECT ANSWER - Most effective compression between 2 bone
fragments. Pulls fragments together producing pressure across the fracture line. Purchase is
acheieved on the distal fragments while being able to turn freely to proximal fragment.
Clinical application of lag screws - CORRECT ANSWER - Used to compress fractures.
Used to hold plates on bone. Threads only engage FAR cortex.
Headless/Herbert screw - CORRECT ANSWER - Cannulated. Interfragmentary
compression. Threads at both ends.
ACTUAL Exam Questions and CORRECT
Answers
Principles of AO - CORRECT ANSWER - Anatomical reduction, Stable internal fixation,
preservation of blood supply, early mobilization
Fixation - CORRECT ANSWER - External fixation is a temporary solution for trauma.
Internal can be temporary or permanent. Helps fuse or heal fracture sites.
Principles of plate fixation - CORRECT ANSWER - The tension band. Conversion of
tensile forces to compression forces on the convex side of loaded bone. Screw generally should
not be placed less than 1 cm (10mm) from fracture line.
Device screw features - CORRECT ANSWER - Headed/Headless, Fully or partially
threaded, Self tapping or self drilling tip, Thread pitch is distance between threads.
Cancellous Screws - CORRECT ANSWER - Larger thread to cut through SOFT bone.
Large thread height and large thread pitch.
Corticol Screws - CORRECT ANSWER - Smaller threads because of hard corticol bone.
Short thread forms. Short thread height and a short thread pitch.
Hollow and solid screws - CORRECT ANSWER - Hollow provide guidance for k-wires.
Solid are stronger than hollow.
Cannulated screws - CORRECT ANSWER - Utilize a k-wire/guide pin. Typically self-
drilling and self-tapping. Both headed and headless types provide compression at the fracture
site. Length is determined by placing gauge over k-wire.
, Headless screws - CORRECT ANSWER - Both ends with threads, middle without.
Always cannulated.
Headed screws - CORRECT ANSWER - Certain proportion to shaft. Contacts bone to
outside.
Self-tapping screws - CORRECT ANSWER - Designed to cut pattern into bone.
Self-drilling screws - CORRECT ANSWER - No need to drill pathway.
Blunt tip screws - CORRECT ANSWER - Used for soft tissue protection.
Solid core screw - CORRECT ANSWER - Basic orthopedic screw; typically fully
threaded and self-tapping. Instruments used are bone forceps, drill guide, drill bit, depth gauge,
screw driver.
Screw and Drill bit sizing - CORRECT ANSWER - Screw sizing is the thread major
diameter and overall length. Principle drill replicates the minor thread diameter. Over drill bit
size corresponds to the major thread diameter. Allows fully threaded screw to be used as a
partially threaded screw when the near fragment is drilled.
Lag Screw - CORRECT ANSWER - Most effective compression between 2 bone
fragments. Pulls fragments together producing pressure across the fracture line. Purchase is
acheieved on the distal fragments while being able to turn freely to proximal fragment.
Clinical application of lag screws - CORRECT ANSWER - Used to compress fractures.
Used to hold plates on bone. Threads only engage FAR cortex.
Headless/Herbert screw - CORRECT ANSWER - Cannulated. Interfragmentary
compression. Threads at both ends.
