Don’t Touch Lesions

Postraumatic

• myositis ossificans
• avulsion injury
• cortical desmoid
• degenerative geodes
• discoid vertebral sclerosis
• healing fracture callus
• pseudodislocation of the humerous (fracture and hemarthrosis)

Normal Variants

• dorsal (articular) lucent defect of patella
• pseudocyst of humerus
• os odontoideum

Benign Lesions

• Nonossifying fibroma
• bone islands
• unicameral bone cyst
• bone infarction

Bowing deformity

• traumatic injury to radius and ulna without fracture
• if untreated, pronation and supination reduced
• must be broken and reset

Galeazzi’s fracture

fractured distal RADIUS with dislocation of distal ulna

Monteggia’s fracture

fracture of ULNA with dislocation of radial head

Barton’s fracture

• intra-articular radial fracture
• dorsal angulation
• plus radiocarpal dislocation
• see Colles’ fracture

Smith fracture

• fracture of distal radius and ulna with volar angulation
• opposite of Colles’ fracture

Colles’ fracture

• fall on outstretched hand
• fracture of distal radius and ulna with dorsal angulation
• metaphyseal, epiphyseal region
• see Frykman classification
• opposite of Smith fracture
• see Barton’s fracture (+dislocation)

Triquetrial fracture

Avulsed fragment on lateral view

Fracture of scaphoid

• High potential for AVN to the proximal fragement (blood supply begins distally)
• Trauma with pain over the snuff box
• If high clinical suspicion and negative film, cast and refilm in 1 week:

1. Diffuse osteopenia and hyperemia around the fracture site
2. Or just get MRI

• AVN = increased density of proximal pole of scaphoid

Rotary subluxation of the scaphoid

• rupture of scapholunate ligaments causing scaphoid to rotate dorsally
• AP view = Terry Thomas sign (David Letterman sign)

Hook of the Hamate fracture

• Fall on outstretched hand, athletes who hold bats or rackets that lever off hook
• Very rare, requires carpal tunnel view to see
• Bony protruberance off the hamate on the ulnar aspect of the carpal tunnel
• Do CT if strong clinical suspicion and plain film negative

Lunate and Perilunate dislocation

• best seen on lateral wrist view
• fall on outstretched hand

Gamekeeper’s thumb

• avulsion on the ulnar aspect of the first MCP
• torn ulnar collateral ligament
• requires ortho consult, internal fixation

Mallet finger fracture

• baseball finger
• avulsion at base of distal phalynx

Bennett’s Fracture

• intra-articular, dislocation fracture at base of the first metacarpal/thumb, into CMC joint
• unstable; requires internal fixation, rec ortho consult
• fragment is being pulled by APL
• Rolando’s fracture = comminuted Bennett’s Fracture

Frykman classification

describing Colles’ radial and ulnar fractures
Type 1 = R, extra-articular
Type 2 = R + U, extra-articular
Type 3 = R, intra-articular radiocarpal
Type 4 = R + U, intra-articular radiocarpal
Type 5 = R, intra-articular distal radioulnar joint
Type 6 = R + U, intra-articular distal radioulnar joint
Type 7 = R, intra-articular both radiocarpal and radioulnar joints
Type 8 = = R + U, intra-articular both radiocarpal and radioulnar joints

Medial Collateral Ligament

“wavy” appearance on MR
prevents valgus angulation
2 layers separated by small bursa:

1. tibiocollateral ligament (superficial)
2. meniscofemoral and meniscotibial ligaments (deep)

grade 1

• surrounding edema

grade 2

• thickening
• partial rupture

grade 3

• complete rupture
• loss of ligament continuity

Pellegrini-Stieda = post-traumatic calcification around MCL origin related to prior trauma

Brodie’s Abscess

• infection becomes chronic
• radiolucent, well-defined geographic lesion with surrounding diffuse sclerosis
• 2/3 in metaphysis, 1/3 in diaphysis

AC joint separation

• complicaitons
• hepterotopic calcifaction-ossification
• posttraumatic osteolysis of distal clavical
• secondary osteoarthritis
• get weight bearing views, and comparison with other shoulder

Types
I = Sprain

• stretching of the AC ligament
• AC joint is stable
• CC ligament intact
• only seen on stress views, widening of AC joint

II = Subluxation

• partial or complete rupture of AC ligament
• partial disruption of CC ligament
• widened AC (less than 5 mm or 50%), normal CC
• arthroplasty may be needed

III

• disruption of both AC and CC (more than 5 mm or 50%)
• widening of AC and CC on routine film

IV = posterior

• AC and CC ligaments disrupted
• Coracoacromial ligament intact
• distal end of clavical inferior and posterior to acromion (axillary views)

V = superior

• Type IV plus sternoclavicular separation
• marked widening of AC and CC, sternoclavicular dislocation

VI = inferior

• distal end of clavicle displaced inferiorly and lodges in biceps and coracobrachialis muscles
• distal end of clavicle lies inferior to acromion

link

Simple Bone Cyst

• unicameral bone cyst; simple bone cyst
• fluid-filled cavity
• fallen fragment sign: detached fragment of bone in dependent portion of cyst
• males:females 2:1
• calcaneus, long bones (esp children)
• lucent, well-demarcated, geographic
• long axis parallel to long bone
• broader toward metaphysis than diaphysis
• pathological fractures