MSK Trauma

Table of Contents

• General resources
• Normal shoulder measurements
• Lateral wrist anatomy
• Wrist ligaments
• Ankle ligaments
• Pelvic radiograph search pattern
• Proimal femur anatomy

MSK Trauma Quick Reference Guides

• Hand and Wrist
• Elbow
• Distal Humerus
• Proximal Humerus
• Clavicle
• Scapula
• Pelvic
• Acetabulum
• Proximal Femur
• Knee
• Mid Tibia/Fibula
• Ankle
• Foot

For spine imaging please see the neuroradiology section.

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GENERAL RESOURCES

• Atlas of Normal Variants
• Atlas of Orthopedic Hardware by Location
• Normal for Age by Gender
• Upper Extremity Trauma
• Lower Extremity Trauma
• Pelvis and Hip Trauma
• Bone Tumor Identification (Stanford)

NORMAL SHOULDER MEASUREMENTS

Lateral Wrist Bony Anatomy

Wrist Ligaments

Ankle Ligaments

PELVIC RADIOGRAPH SEARCH PATTERN

Source: Khurana B, Sheehan SE, Sodickson AD, Weaver MJ. Pelvic ring fractures: what the orthopedic surgeon wants to know. Radiographics. 2014;34(5):1317-1333. doi:10.1148/rg.345135113

Source: Scheinfeld MH, Dym AA, Spektor M, Avery LL, Dym RJ, Amanatullah DF. Acetabular fractures: what radiologists should know and how 3D CT can aid classification. Radiographics. 2015;35(2):555-577. doi:10.1148/rg.352140098

Proximal Femur Anatomy

HAND AND WRIST

Hand

WRIST

Distal Radius Fractures

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• Loss of volar tilt
• Loss of radial inclination
• Shortening of the radius relative to the ulna
• Intraarticular extension
• Diastasis or depression at the intraarticular fracture site
• Comminution
• Associated ulnar styloid fracture
  • Location and degree of displacement
  • If styloid base fracture, is the DRUJ and TFCC intact
• Disruption of the carpal arcs

Named Fractures

• Just describe the fracture, don’t use eponyms

Galeazzi Fracture-Dislocation

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• Description of radial fracture
• Degree of shortening
• DRUJ dislocation direction

• Fracture of the distal radius with dislocation of the DRUJ
• Classification
  • Type I: dorsal displacement of the distal radius
  • Type II: volar displacement of the distal raidus

Essex-Lopresti fracture-dislocation

• Fracture of the radial head with dislocation of the DRUJ and rupture of the interosseous membrane

ELBOW

• Radial Head Fractures
• Elbow Dislocation
• Monteggia Fracture Dislocation

Radial Head Fractures

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• Degree of displacement
• Amount of articular surface involved (%)
• Presence of comminution or dislocation

Mason-Johnston Classification

• Type 1 – No or minimal (<2mm) displacement
• Type 2 – Displacement >2mm, >30% <50% articular surface involvement
• Type 3 – Comminution of the radial head without dislocation
• Type 4 – Comminution and dislocation of the radial head

Elbow Dislocation

• Posteriolateral most common
• Complex = dislocation + fracture
• Associated fractures
  • Medial epicondyle
  • Radial head/neck
  • Coronoid process
• Terrible triad – get CT if 2/3 seen to exclude the third injury
  • Posterior elbow dislocation
  • Radial head fracture
  • Coronoid process fracture

Stages of Dislocation

• Stage 1 – Damage to lateral ligamentous structures (LUCL, RCL)
  • Posterolateral rotary instability
• Stage 2 – Capsular and lateral soft tissue damage
  • Trochlea is perched on the coronoid process
• Stage 3 – Vary degrees of damage to medial structures (anterior bundle MCL) with frank dislocation

Monteggia Fracture Dislocation

• Ulnar fracture with proximal radius dislocation
• All will go to surgery

Bado Classification

• Type 1 – Most Common – Anterior angulation of the ulnar fragment apex with anterior dislocation of the radius
• Type 2 – Posterior fracture angulation of the ulna and radial head
• Type 3 – Pediatrics – Ulnar metaphyseal fracture with lateral dislocation of the radial head
• Type 4 – Fracture of the proximal radius and ulna

DISTAL HUMERUS

• Coronoid Process Fractures
• Olecranon Fractures

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• Column involvement – medial or lateral
• Direction and degree of displacement of epicondylar avulsion fractures and single column fractures
• Presence of comminution or two column injury

Classification System

Coronoid Process Fractures

Classification System

• Type 1 – Transverse tip fracture
• Type 2 – Anteromedial facet involvement – MCL injury
• Type 3 – Base of coronoid process (>50% disruption)

Olecranon Fractures

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• Degree of displacement
  • >2mm displacement = surgery
• Presence of comminution
  • Comminution = surgery

Mayo Classification System

• Type 1 – Non-displaced
• Type 2- Intact MCL, displaced >3mm
• Type 3 – Displaced, unstable

PROXIMAL HUMERUS

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• Typically do not list the parts since the ortho may disagree
• Part = >1cm displacement or 45 degree angulation

CLAVICLE

Clavicle Fracture

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• Fracture location along the shaft (lateral third, middle third, medial third)
• Angulation and fracture end displacement (including direction)
• Comminution
• Degree of overlap
• Acromioclavicular and sternoclavicular joint integrity
• Coracoclavicular distance

In general, if >100% displacement will be managed operatively

Rockwood Classification of Acromioclavicular Joint Injury

Type I	Clavicle not elevated relative to the acromion
Type II	Clavicle elevated but not above the superior border of the acromion
Type III	Clavicle elevated above the superior border of the acromion CC distance is less than twice normal (<25 mm)
Type IV	Clavicle displaced posterior into the trapezius
Type V	Clavicle is elevated and CC distance is more than double normal (>25 mm) Consider weight-bearing projections
Type VI	Rare; clavicle inferiorly displaced behind coracobrachialis and biceps tendons

SCAPULA

• Scapular Neck Fractures
• Glenoid Fossa Fractures

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Commonly involves:

• Scapular body
• Acromion
• Coracoid process
• Glenoid neck or articular surface (requires surgical repair)

Superior Suspensory Complex – support complex of the shoulder. Disruption of any two = unstable injury requiring surgery. Disruption of three = floating shoulder (high energy trauma)

1. Glenoid process
2. Coracoid process
3. Coracoclavicular ligament
4. Distal end of the clavicle
5. Acromioclavicular joint
6. Coracoacromial ligament
7. Acromial process

Scapular Neck Fracture Classification

• Type 1 – Nonangulated, nondisplaced
• Type 2a – Shortened or displaced > 1 cm
• Type 2b – Angulated > 40 degrees

Ideberg Classification of Glenoid Fossa Fractures

Type 1a	Anterior rim
Type 1b	Posterior rim
Type 2	Transverse  to lateral margin
Type 3	Transverse to superior margin
Type 4	Transverse to medial margin
Type 5a	Transverse lateromedial
Type 5b	Transverse superomedial
Type 5c	Transverse superomediolateral
Type 6	Comminuted crush

PELVIC FRACTURES

• Stable Fractures
• Pelvic Ligaments
• Pelvic Ring Fracture Classification

Stable Pelvic Fractures

• Isolated pubic ramus of ischium fracture
• Unilateral fractures of both rami
• Isolated sacral fractures (usually transverse)
• Avulsion fractures
• Duverney fracture – peripheral fracture to the iliac wing (associated with ileus)

Pelvic Ligaments

Young and Burgess Classification of Pelvic Ring Fractures

ACETABULAR FRACTURES

• Anatomy
• Acetabular Fracture Classification

Anatomy

Judet and Letournel classification of Acetabular Fractures

Anterior Column – Pelvic brim, anterior wall, superior pubic ramus, anterior iliac wing

Posterior Column – Greater and lesser sciatic notch, posterior wall, ischial tuberosity

PROXIMAL FEMUR FRACTURES

• Types of fractures
• Intracapsular fractures
• Dislocation
• Extracapsular fractures

Types of Fractures

Intracapsular Fractures

Pipkin Classification of Femoral Head Fractures

Type	Characteristics
Type I	Inferior to the fovea centralis
Type II	Superior to the fovea centralis
Type III	Combination of type I/II with femoral neck fracture
Type IV	Combination of type I/II with acetabular fracture

Dislocation

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• Type of dislocation
  • Posterior > anterior
• Associated femoral neck fracture
  • Reduction is contraindicated with coexisting femoral neck fracture
• Associated femoral head impaction fracture
  • More common with anterior dislocation
  • Requires THA

Femoral Neck Fractures

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• Location
  • Subcapital
  • Transcervical
  • Basicervical
• Displaced or nondisplaced
• If elderly – Garden Classification – the worse grade the higher risk of AVN

Garden Classification of Femoral Neck Fractures

Type	Characteristics
Type 1	Incomplete or valgus impacted
Type 2	Complete, nondisplaced
Type 3	Complete, partially displaced
Type 4	Complete, fully displaced

Extracapsular Fractures

Intertrochanteric Fractures

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• Involvement of the posteromedial cortex
  • If intact = stable
  • If involved = unstable
• Reverse fracture – unstable
• Subtrochanteric extension – unstable

Evan-Jensen Classification of Intertrochanteric Fractures

Type	Characteristics	Stability
Type I	Two-part nondisplaced fracture	Stable
Type II	Two-part minimally displaced fracture	Stable
Type III	Three-part with loss of posterolateral support	Stable
Type IV	Three-part with loss of posteromedial support	Unstable
Type V	Four-part with loss of both posteromedial and lateral support	Unstable
Type R	Reverse obliquity fracture	Unstable

Lesser Troachanter Fracture – if isolated think malignancy

Subtrochanteric Fractures

• High rate of complications
• Trauma – comminuted fractures
• Elderly – spiral fractures
• Bisphosphonate therapy
  • Transverse (primarily); medially may be oblique
  • Lateral cortex, medial spike if complete fracture
  • No or minimal comminution
  • Endosteal or periosteal thickening

Seinsheimer Classification of Subtrochanteric Fractures

Type	Characteristics
Type 1	Any fracture with <2mm displacement
Type 2A	Two-part transverse fracture
Type 2B	Two-part spiral fracture with the lesser trochanter in the proximal fragment
Type 2C	Two-part spiral fracture with the lesser trochanter in the distal fragment
Type 3A	Three-part spiral fracture, the third fragment is the lesser trochanter
Type 3B	Three-part fracture with third part a butterfly fragment
Type 4	Four or more fragments
Type 5	Any fracture with extension into the greater trochanter

KNEE

• Distal femur fractures
• Fibular fractures
• Patellar fractures
• Plain film signs of ligamentous injury
• Tibial fractures
• Dislocation
• Proximal tibiofibular joint dislocation

Distal Femur Fractures

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• Fracture fragments
• Articular or extraarticular
  • If articular measure the articular surface step-off
• Presence of floating knee – extra-articular fractures of the proximal tibia and distal femur
• If fracture recommend inmaging of the proximal femur and hip
• If posterior displocation – recommend CTA to evaluation popliteal injury

AO/OTA Classification of Distal Femur Fractures

Type	Characteristics
A1	Simple, nondisplaced
A2	Metaphyseal wedge
A3	Complex metaphyseal
B1	Sagittal fracture of the lateral condyle
B2	Sagittal fracture of the medial condyle
B3	Coronal fracture of one or both condyles (Hoffa fragment)
C1	Simple articular and metaphyseal
C2	Comminuted metaphyseal component with simple articular componenet
C3	Comminuted articular and metaphyseal components

Fibular Fractures

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• Location of fracture (fibular head, avulsion, fibular shaft)
  • Fibular head fracture – asociated with peroneal nerve injury and foot drop
    • Also association with posterolateral corner injury and instability
  • Fibular shaft fracture – Recommend imaging of ankle to exclude a Maisonneuve fracture 
• Degree of subluxation
  • Anterolateral
  • Posteromedial
  • Superior

Patellar Fractures

• Transverse fracture most common
• Sugical management
  • >2mm incongruity at articular surface
  • >3mm separation of fracture fragments
  • Disruption of extensor mechanism

AO/OTA Classification of Patellar Fractures

Plain Film Signs of Ligamentous Injury

• Tibial spine avulsion fracture – associated with MCL and medial meniscus injury
  • Can be isolated and cause knee instability
  • If seen – recommend MRI

Deep Notch Sign – impaction fracture of the lateral femoral condyle associated with ACL injury

Tibial Fractures

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• Size, number and location of fracture fragments and fracture lines
• Presence of contralateral joint space widening
• Split, depressed, or bicondylar morphology
  • Nonsurgical management if diastasis <3-4 mm and depression <4-5mm

Schatzker Classification of Tibial Plateau Fractures

Type	Characteristics
Type I	Split fracture with no depression
Type II	Lateral split fracture with depression of the weight bearing portion
Type III	Focal depression of articular surface without split
Type IV	Medial plateau fracture
Type V	Bicondylar split fracture +/- depression
Type VI	Bicondylar split fracture with dissocation of the metaphysis from diaphysis by transverse fracture component

Knee Dislocation

• Based on the direction of the tibia
• Anterior most common
• Posterior – dashboard injury
• Can have medial or lateral as well as rotary dislocation
• All should undergo vascular imaging to evaluate for popliteal injury

Proximal Tibiofibular Joint Dislocation

Ogden Classification of PTFJ Dislocation

Type	Characteristics	Notes
Type I	PTFJ subluxation
Type II	Anterolateral	Most common
Type III	Posteromedial	Associated with peroneal nerve injury (foot drop)
Type IV	Superior	Associated with fracture/dislocation of ankle or distal tibia

MID TIBIA/FIBULA

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• Simple, complex, or wedge
• Shortening or distraction
• Presence of intercalated fragment

AO/OTA Classification

• Similar schema for fibular fractures
• Butterfly fragment – triangular comminuted fragment of bone that does not involve the entire circumference of the shaft
• Ring butterfly fragment – involved entire circumference of shaft
• Bayonet apposition – overriding fracture fragments
• Segmental fracture – intercalated fragment with impaired vasculartity

ANKLE FRACTURES

• Lauge-Hansen classification of ankle fractures
• Tibial plafond fractures

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• Fractures – level and pattern
• Ligaments – lateral medial clear space
• Weber/Lauge-Hansen – look for missed injury based on classification
• Dislocation

Lauge-Hansen Classification of Ankle Fractures

Tibial Plafond Fractures

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• Number and location of major fragments at the level of the articular surface
• Degree and location or articular depression
  • >2-3mm is considered significant
• Associated tendon injury or entrapment

• Disruption of the syndesmosis
• Bony fragments in the syndesmosis
• Retinaculum injury

Ruedi and Allgower Classification of Pilon Fractures

Type	Characteristics
Type I	Cleavage fracture with no major articular disruption
Type II	Displaced fracture with minimal impaction or comminution
Type III	Displaced fracture with significant articular surface comminution and metaphyseal impaction

FOOT

• Talar fractures
• Calceneal fractures
• Midfoot
• Forefoot

Talus

Source: Melenevsky Y, Mackey RA, Abrahams RB, Thomson NB 3rd. Talar Fractures and Dislocations: A Radiologist’s Guide to Timely Diagnosis and Classification. Radiographics. 2015 May-Jun;35(3):765-79. doi: 10.1148/rg.2015140156. PMID: 25969933.

Talar Body Fractures

Sneppen Classification of Talar Body Fractures

Type	Characteristics
A	Compression or osteochondral dome fracture
B	Coronal shear fracture
C	Sagittal shear fracture
D	Posterior tubercle fracture
E	Lateral tubercle fracture
F	Crush comminuted fracture

Talar Process Fractures

Posterior Process Fracture (Shepard Fracture) – Mimics Os Trigonum

Posteromedial Tubercle Fracture (Cedell Fracture)

Lateral Process Fracture

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• Hawkins classification
• Degree of displacement
  • >2mm = ORIF
• Largest fracture fragment size
  • >1cm can undergo fixation, smaller may need to be excised

Hawkins Classification of Lateral Process Fractures

Type	Characteristics
Type I	Most common – simple fracture with a single fracture line extending from the talofibular articulation to the subtalar joint
Type II	Comminuted fracture involving the entire lateral process and both articular surfaces
Type III	Only involves the subtalar joint at the anterior-inferior portion of the posterior articular process

Talar Neck Fracture

Hawkins-Canale Classification of Talar Neck Fractures

Type	Characteristics	Risk of osteonecrosis
Type I	Nondisplaced talar neck fracture	~10%
Type II	Talar neck fracture and talocalcaneal dislocation	~30%
Type III	Talar neck fracture, talocalcaneal dislocation, and tibiotalar dislocation	>90%
Type IV	Talar neck fracture, talocalcaneal dislocation, tibiotalar dislocation, talonavicular dislocation	>90%

Talar Head Fractures

• Least common fracture of the talus
• Fracture of the articular surface of the talus at the talonavicular articulation – associated with dislocation
• Recommend CT to evaluate for extension to talar neck, also associated with midfoot fractures
• Hawkin sign – lucent band parallel to subchondral bone plate of talar dome due to hyperemia
  • If seen – osteonecrosis will not develop
  • 4-9 weeks after fracture

Calcaneal Fractures

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• Look for cortical fragments entrapped between dominant fragments – can impede reduction 
• Extension into calcaneocuboid joint 
• Number of sagittal fracture lines entering the posterior subtalar joint 
• Degree of depression of articular fragments 
• Look for peroneal retinaculum avulsion
• Look for peroneal tendon entrapment 
• Fragments inferior to sustentaculum tali – may entrap flexor hallicus longus tendon, tibial nerve 
• Sanders classification

Sanders Classification of Calcaneal Fractures

Midfoot Fractures

Midfoot Sprain Injuries

Navicular Fractures

Type	Characteristics	Notes
Navicular Avulsion		Most common Conservative management
Navicular Tuberosity Fracture	Insertion of the tibialis posterior tendon	ORIF
Type I Body Fracture	Transverse in the coronal plane	No angulation of the midfoot
Type II Body Fracture	Sagittal with dorsomedial subluxation of the talonavicular joint
Type III Body Fracture	Comminuted fracture with lateral subluxation of the midfoot

Forefoot Fractures

Lisfranc Injury – low energy trauma

Source: Siddiqui NA, Galizia MS, Almusa E, Omar IM. Evaluation of the tarsometatarsal joint using conventional radiography, CT, and MR imaging. Radiographics. 2014 Mar-Apr;34(2):514-31. doi: 10.1148/rg.342125215. PMID: 24617695.

• Lateral or dorsal displacement of M2 on C2 – most reliable
  • Step-off sign on lateral view

• >2mm diastasis between M1 and M2 base on AP radiograph
• Fleck sign

Lisfranc Fracture Dislocation – high energy trauma

• Homolateral – all metatarsals displaced laterally
• Divergent – M1 displaced medially, M2-M5 displaced laterally
• Isolated – M1 displaced medially, no other metatarsals displaced
• Don’t get bogged down with all the small fracture fragments

General Forefoot Injuries

• If phalangeal tuft fracture – correlate for nailbed injury to exclude open fracture
  • Great toe most common
• Jones fracture – prone to nonunion
  • Do not confuse with Os Vesalianum
• Peroneus brevis avulsion – AKA Dancer or Pseudo-Jones Fracture
• March/Stress Fractures – similar
• Freiberg Disease – Osteochondrosis of the metatarsal head
  • Adolescents, F>M
• Turf Toe – really a ligamentous injury, sometimes fracture of the sesamoids is called turf toe
• Müeller-Weiss – osteonecrosis of the navicular in adults