Skeletal Trauma

Skeletal Trauma- Plain film Trauma Terminology Review •Dislocation = Complete loss of juxtaposition of normally complementary articular surfaces

•Subluxation = Partial loss of juxtaposition of normally complementary articular surfaces

•Diastasis = Separation of opposing surfaces at a symphysis, syndesmosis, suture or other minimally moveable articulation

•Compound fracture = fracture with protrusion of bone through skin; “open” fracture.

•Closed fracture = bone fractured, but not protruding thru skin.

Trauma Terminology Review

•Occult fracture = fracture not immediately apparent on plain film xray

•Complete fracture = fracture line completely thru the diameter of bone

•Comminuted fracture = more than two pieces of bone result •Avulsion fracture = Piece of bone pulled free due to traction on musculotendious or ligamentous insertion.

•Incomplete fracture = fracture does not extend completely through diameter of bone –Torus fracture/buckle fracture –Greenstick fracture –Plastic deformity of bone

Trauma Terminology Review

•Pathologic fracture = fracture of bone due to weakening caused by underlying pathologic process (benign or malignant)

•Stress/fatigue fracture = application of repetitive stress to bone

results in microfratures of the trabeculae which eventually exceed to body’s ability to repair. Not result of an acute injury.

Fx Description •1. Open vs. Closed

•2. Complete or Incomplete

–Complete •Comminuted •Non-comminuted (Simple)

•3. Direction & Position •4. Alignment •5. Apposition •6. Rotation

Fracture description/evaluation •Anatomic site and extent of fracture

–Diaphysis, metaphysis, articular involvement, etc.

•Type of fracture

–Complete vs incomplete –Open vs closed –Simple vs comminuted

•Alignment

–Displacement, angulation, rotation or distraction –Always describe position of distal part relative to proximal part –Use clear reference (“apex of angle is medial or lateral”, or use varus/valgus descriptor

Trauma Terminology Review

•Alignment = position of the distal fragment relative to the proximal

one; usually refers to the presence/absence of angulation. –In the spine, always describe the position of the superior vertebra of the involved motion segment relative to the one below.

•Apposition = describes the position of the fractured surfaces one to another. Often described as the percentage of contact between surfaces, (100% = complete contact)

Fracture description/evaluation •Direction of fracture (relative to long axis of bone)

–Oblique, spiral, transverse/horizontal, longitudinal

•Special features of fracture

–Compression, impaction, depression, etc

•Associated abnormalities –Dislocation –Diastasis

•Special type of fracture –Stress –pathologic

Fracture description/evaluation Fracture description/evaluation Fracture description/evaluation Fracture description/evaluation Fracture description/evaluation Fracture description/evaluation Fracture description/evaluation Fracture healing- vascular supply

•Medullary arts. supply the inner 2/3 of the cortex, according to some authors; –others state endosteal vessels supply more.

•Endosteal vessels are dominant in the revascularization and healing process •Outer 1/3 of the cortex supplied by periosteal vessels –periosteal vessels especially important in displaced fractures; endosteal vessels often disrupted. disrupted. –Intimate anastomosis exists between muscle and periosteal vessels; –muscular pumping and muscular vascularity important for rere-vascularization of external callus. –Physical therapy and exercise (isometric) important for blood supply

Three stages of healing:

•Inflammatory •Reparative •Remodeling •Inflammatory

–Hematoma formation –Osteocyte death, vasodilatation migration of acute inflammatory cells into the wound.

Three stages of healing:

•Inflammatory •Reparative •Remodeling

•Reparative

–Vascular dilation –New vessel proliferation –Mesenchymal cell proliferation –Change from acid to alkaline pH –Collagen production in wound –Cartilage and bone fomration begins

Three stages of healing:

•Inflammatory •Reparative •Remodeling •Remodeling

–osteoblastic resorptioin –new bone formation – prominent endosteal and periosteal callus formation

MECHANISMS OF BONE HEALING •TWO BASIC TYPES OF CALLUS –INTERNAL –EXTERNAL

EXTERNAL / PERIOSTEAL CALLUS

•The most reliable radiographic sign of beginning osseous union. •The fastest type of callus to form •Very dependent upon blood supply of surrounding soft tissues. •more perioteal callus beneath areas of thick soft tissue •Very tolerant to limited motion at fracture site •Structurally oriented perpendicular to long axis of cortices

–Longitudinal orientation of bone will be re-established upon remodeling of periosteal callus

Periosteal callus

•Radial fracture stablized with a pin shows periosteal callus •Intramedullary callus seen as band of increased density across metaphysis of ulna

EXTERNAL / PERIOSTEAL CALLUS

•Periosteal callus, because of it's peripheral location, is strongest •The rigidityrigidity-efficiency of the tissue increases with the fourth power of the distance from the center of rotation or bending.

•Periosteal callus does not form in intracapsular areas; no periosteum -Periosteal callus does not form in flat skull bones

ENDOSTEAL/INTERNAL OR LATE MEDULLARY CALLUS

•Predominates when external/periosteal callus has

failed •Assisted by rigid immobilization •Slow, steady bridging •Medullary callus forms the earliest osseous bridging of fracture line

PRIMARY BONE UNION

•Depends upon normal mechanism of bone turnover which occurs continuously •Must have absolute rigid immobilization; eg. occurs when compression plate internal fixation is used properly. •Primary angiogenic ossification occurs; secondary osteotones form directly without an intervening cartilage step in development. –Longitudinally oriented osteotones formed around blood vessels running across the fracture line.

•Depends on good endosteal circulation. •Very slow process

•Periosteal callus may be minimal if primary bone union is being achieved in conjunction with internal fixation device

SECONDARY BONE UNION

•Occurs when there is a gap between bone ends

(poor apposition and/or alignment) that must be filled with new bone. •Results mostly as result of excessive periosteal callus that undergoes all the intermediate steps of bone formation –Granulation tissue – fibrous tissue – fibrocartilage – woven bone- compact bone

WHEN IS A FRACTURE "HEALED"?

• Clinically: a fracture is healed when there is no

local tenderness or motion of bone across fracture site when manually stressed by examining physician. –Clinical union precedes osseous union, and may occur in 6-8 weeks, average. –Removal of cast and limited use of the part may be instituted by orthopedist at this time –Clearly visible fracture line may be present on x-ray

•Radiographically: Strict radiographic criterion for

osseous union is complete obliteration of the fracture line and evidence of remodeling.

WHEN IS A FRACTURE "HEALED"?

• For practical purposes, a fracture with bridging

callus surrounding 50% of the fracture site with no pain or motion on clinical testing may be considered united;

–patient should avoid rigorous activity until further healing occurs

Fracture healing: Favorable factors

•FX at bone end where bone is cancellous and blood supply good •Blood supply to fragments not interrupted •Soft tissue injury mild •End to end apposition of bone fragments •No infection at fx site •Adequate immobilization •Compression of fx with weightbearing

Fracture healing: Unfavorable factors

•Wide separation of fx with soft tissue interposition •Distraction of fx by traction. •Severe comminution of fx with extensive ST damage •Bone lost due to surgery or injury •Poor immobilization; esp. if rotatory motion allowed. •Interrupted blood supply •Infection •Superimposed systemic illness (diabetes, malnutrition, -OH) •Advanced age

Incomplete fractures- torus #

•Child or adolescent •Easily overlooked! Potential liability + •Typically not a serious injury, but bone is weak and should be protected to avoid further injury •“Buckle” of cortex, typically due to axial loading •Common in distal radius

Incomplete fractures- torus #

•August 14- hx of fall on outstretched hand (next slide follow-up)

Incomplete fractures- torus # •Sept 22-

Intramedullary and periosteal callus

Incomplete fractures- plastic deformity

•No focal cortical infraction is visible, but comparison of the left ulna with the normal right side shows visible bending of the bone

Stress fractures

•Weight bearing bones esp –2nd MT –Tibia –Fibula –Calcaneus

•Healing response is often 1st plain film finding •MR very sensitive to marrow edema changes for early Dx.

Stress fractures- “March” fracture •Fx healing is first plain film finding •2nd MT most common •Seen in army recruits marching with heavy packs •Also seen in runners or •Patient with altered gait pattern may develop –Bunion, post-surg, etc.

Stress fractures- “March” fracture •Fx healing is first plain film finding •2nd MT most common •Seen in army recruits marching with heavy packs •Also seen in runners or •Patient with altered gait pattern may develop –Bunion, post-surg, etc.

Stress fractures- tibia

•Runners/joggers •Otherwise inactive individuals beginning an aggressive exercise program of walking •May be dx as “shin splints”

Chronic trauma

X-ray of elderly Chinese woman- dx?

Why at least 2 views?

AP film of patient with recent trauma- do you really need another film?

Spondylolysis

•Many (?most?) are the result of stress fracture •Acute pathogenesis is supported by some •Incidence

– 3-7% in US, with higher numbers in Eskimo population –Incid rises from age 3 – 20 yrs., then does not increase in frequency –2:1 male prediliction –Increased incidence in association with spina bifida •Seen by some as evidence of congenital etiology, it more likely represents the additional stress created by an open vs a closed ring.

•L5 most common (67%), then L4 > L3 >L2 •Cervical spine not commonly involved, but C6 predilicted •Most often bilateral, but may be unilateral •Displacement usually occurs within first two years, if at all

Spondylolysis •Myerding grading

–Divide sacral base into 1/4ths from back P to A –Into which 1/4th does a line along posterior aspect L5 vert body fall? –Grades I-IV; Grade V if spondyloptosis occurs.

•% assessment

–Estimate displacement of L5 relative to the total (100%) P-A measurement of sacral base.

Spondylolysis •L4 spondylolysis

Spondylolysis

•May be unstable- flexion/extension may be useful

Spondylolysis

•Spondyloptosis may occur •“inverted Napolean hat” sign on AP view due to overlap of L5 on sacral base

Spondylolysis

•Cervical spondyolysis most common at C6 •Spina bifida is typically associated •Instability may be present

Fractures involving the growth plate •Salter-Harris classification

–Type I = A “slip” of the epiphysis due to separation thru the physis- injury to cartilage plate –Type II – “Slip and a chip”; fracture thru physeal plate and obliquely thru corner of adjacent metaphysis –Type III – “A Slip and a crack”; fracture thru epiphysis (crack), across physis (slip) –Type IV – Fracture thru epiphysis, physis and metaphysis; no significant slippage of physis/metaphysis –Type V – Compression/impaction injury of physis

Salter-Harris # Type I

•Approx. 6% of epiphyseal fractures •Common locations are distal extremities •Easily overlooked without complete series •Slipped Femoral Capital Epiphysis (SFCE) is a chronically acquired S-H type I fracture

Salter-Harris # Type I

•Note the tibial physis is closed •Offset seen on oblique and wide physis on lateral

Salter-Harris # Type II

•Most common (75%) of the Salter-Harris #s •Easily overlooked without complete series •Approx. 50% in distal radius

Salter-Harris # Type II

•What kind of Salter-Harris injury is present? •What other injury is also present?

Salter-Harris # Type III

•Fracture thru epiphysis (crack) and across physis (slip) •Approx. 8% of all epiphyseal fractures

Salter-Harris # Type III

•Most common location is distal tibia •Optimal reduction especially important due to involvement of articular surface

Salter-Harris # Type IV

•Fracture extends thru metaphysis, physis and epiphysis •Most common sites are lateral condyle of humerus and distal tibia •Approx. 10% of epiphyseal plate fractures •Open reduction typically performed

Salter-Harris # Type V

•Easily overlooked! Initial films may be negative –MR much more sensitive!

•Least common of S-H types •Compressive mechanism of injury •Early growth plate closure may result in limb-length problems •Distal tibia and femur most common

Complications of fracture •Immediate

–Arterial injury –Compartment syndrome –Gasgangrene –Fat embolism –Thromboembolism

•Later

–Osteonecrosis –DJD –Osteoporosis –Aneurysmal bone cyst –Non union –malunion

•Intemediate

–Osteomyelitis – hardware failure –Reflex sympathetic dystrophy –Post-traumatic osteolysis –Refracture –Myositis ossificans –Synostosis –Delayed union

Complications of fracture Delayed vs Non-union

•Delayed union = fracture has not united at the average time for the location and type of fracture.

–Expected healing time quite variable based on site and any favorable/unfavorable factors; –“delayed” is relative term.

Complications: Delayed vs Non-union

•NonNon-union = the repair process has completely stopped and union will not occur without surgical intervention.

•Hypertrophic non-union: demonstrates extensive callus formation, but callus does not bridge; # line persists.

–Associated with local hypervascularity –Rigid internal fixation may be sufficient to allow union to occur. –"Elephant foot" or "horse's hoof" appearance.

•Atrophic type non-union: minimal callus, if any; # line persists. –Incapable of biologic reaction; associated with avascularity. –Requires more aggressive surgical intervention

•Radiographically, the nonnon-union is characterized by a closing of the medullary canal with cortical bone.

Non-union

•Smoothly corticated margins and closed medullary canal on left

characterize atrophic non-union of fibula •Residual fracture line despite bone proliferation and sclerosis in middle frame shows hypertrophic non-union •Far right frame shows malunited fibula and non-union of the tibia

Non-union- what type?

•Hypertrophic “elephant foot” appearance

Malunion

•This case from Greenspan’s text shows residual angular

deformity from a united both-bones fracture of the lower leg (reading left) and subsequent surgical intervention (right) to restore alignment.

Early growth plate closure

•Length disparity and deformity secondary to central

ossification across physeal plate of distal left femur •Distal tibia shows ossification across posterior part of physeal plate, while anterior part not joined. Also note deformity of fibula and disparity of length relative to tibia. •(Cases from Greenspan text)

Avascular necrosis

•41 yr. old man with hx of traumatic hip dislocation •Note the irregular, mixed sclerosis and cystic lucency of the femoral head •Frog-leg projection shows classic “cresent sign”

Avascular necrosis

•56 yr. old female with hx of intracapsular fx of femoral neck which healed after internal fixation device applied. • Irregular sclerosis of femoral head (best seen in tomo on rt) consistent with avascular necrosis

Disuse osteoporosis

•These examples from Greenspan’s text show disuse osteoporosis that may accompany united (left) or ununited (right) fractures. The appearance may be alarming, although not necessarily of clinical importance.

Chronic Regional Pain SyndromeReflex Sympathetic Dystrophy (RSD)

•Also previously reported as Sudeck’s atrophy or causalgia •Believed to be associated with antidromal sympathetic input to the

CNS secondary to trauma to peripheral trauma; overt fracture, neural or vascular injury may or may not be present.

•Characterized by excessive pain (causalgia), not relieved by

immobilization. •Initial soft tissue swelling followed by atrophy of skin/muscles •Predominant X-ray findings are rapidly developing, patchy osteoporosis distal to site of injury and changes (early, swelling; later, atrophy)

Reflex Sympathetic Dystrophy (RSD)

•AKA: Sudeck’s atrophy •Believed to be associated with antidromal sympathetic input to the CNS secondary

to trauma to peripheral trauma; overt fracture, neural or vascular injury may or may not be present. •Characterized by excessive pain (causalgia), not relieved by immobilization. •Initial soft tissue swelling followed by atrophy of skin/muscles •Predominant X-ray findings are rapidly developing, patchy osteoporosis distal to site of injury and changes (early, swelling; later, atrophy)

Infection

•Both bones # with attempted internal fixation (left) •8 weeks later tibia shows motheaten destruction compatible with osteomyelitis (right)

Post-traumatic Myositis Ossificans

•Usually following an injury with significant soft tissue

bleeding/hematoma formation, especially deeper tissues. •Soft tissue mass forms with calcific deposition beginning in 3-4 weeks. •Peripheral calcification of mass is more advanced than central –Ddx periosteal o-sarc

•Calcification may be re-organized to ossification

Post-traumatic Myositis Ossificans

•This AP projection of the thigh demonstrates ossification

along the plane of adductor muscles as a result of previous injury.

Shoulder- dislocation

•Most common presenting dislocation •95% are anterior

– Subcoracoid (most common) –Subglenoid –Subclavicular –Intrathoracic (rarely)

•Commonly associated injuries –Hills-Sachs lesion –Bankhart lesion

Shoulder- Hills-Sachs lesion

•Compression fx of the posterolateral aspect of humeral

head from impact against the antero-inferior aspect of the glenoid fossa. •Creates a “hatchet” deformity

Shoulder- Hills-Sachs lesion

•Axillary (inferior to superior) view shows “hatchet”

deformity of antero-medial humeral head in patient with a posterior dislocation.

Shoulder- Posterior dislocation

•Note the overlap of the humeral head over the glenoid, despite the tangential position of the glenoid fossa.

Shoulder- Posterior dislocation

•Note the posterior position of the humerus on the “y-view” of the shoulder

Shoulder- Bankhart lesion

•Bankhart lesion results from contact of the humeral head against the inferior margin of the glenoid fossa •Bony injury may result, however isolated injury to the cartilagenous labrum may occur –Plain film negative for cartilage injury

Shoulder- Bankhart lesion

•Note the cortical irregularity of the inferior glenoid margin

Shoulder- “flap” fracture

•Thin “flap” of bone from lateral humeral head, extending

into adjacent metaphysis- displaced more at inferior aspect •Is the humerus also dislocated?

Shoulder- Gr. Tub. # and disloc •Thin “flap” of bone from lateral humeral head •Is the humerus also dislocated?

Rotator cuff tear-chronic

•Acromio-humeral space should be measured on the external rotation projection •Measurement of 7mm or less is strong indication of chronic rotator cuff tear –NO relevance to acute tears!

Chronic rotator cuff tear + DJD of AC

•Decrease acromio-humeral space and inferior AC joint osteophyte

formation contribute to impingement syndrome and may precipitate rotator cuff tear •Dec. acromio-humeral space = strong suspicion of chronic cuff tear

Shoulder- AC joint

•Fall on “point” of shoulder typical hx for AC joint

separation •Grade I sprain = normal x-rays; clinical diagnosis •Grade II sprain = Stress views show more than 34mm difference in coraco-clavicular space compared to un-injured side •Grade III sprain = complete coraco-clavicular lig disruption evidenced by a 40 – 50% increase in

coraco-clavicular space (compared to non-injured side); 5mm or more difference side-to-side

Acromioclavicular joint assessment •Diagram and table from Greenspan

Stress view for AC joints

•Note the passive attachment of weight to arms to avoid

active contraction of the shoulder muscles •Can be performed as single view including both AC joints on 7x17 film, if anatomy will fit; otherwise single views on either side.

AC joint fx-dislocation AC joint dislocation

•Normal AC joint space usually 4-5mm max, but up to 8mm may still be normal •Alignment of inferior margin of joint more reliable than superior margin •Normal coraco-clavicular space 13mm maximum

–Gr III sprain likely if more than 50% difference side-side in space

AC joint sprain grade III Grade III AC joint separation

Complication- Post-traumatic osteolysis

•May occur secondary to acute trauma (with or without dislocation) •May also occur in repetitive trauma –Weight-lifting

•Has been reported in many other locations, but distal clavicle is most common •Soft tissue swelling and osteopenia, followed by resorption of distal end of clavicle •May appear irregular or “clean” – almost surgical

Post-traumatic osteolysis- clavicle •Later, marked AC jnt widening due to resorption –Progresses over 12-18 mos. –Up to 3 cm resorption

•Process is self-limiting

–Reparative stage occurs over 4-6 months –Some residual widening of AC joint may persist

•Typical age range 20-40 •Acute trauma or repetitive stress may precipitate

–Weightlifters and those employed in heavy lifting occupations

•Mechanism not well understood. Non-specific synovitis?

Post-traumatic osteolysis- clavicle •MR findings may support diagnosis

Clavicle fracture •Location

–Fx can be classified according to location in the medial (type I), middle (type II) of lateral (type III) third of bone –75-80% of fx occurs in the middle portion of bone •Esp near junction of outer and middle 1/3’s of bone –Only 5% affect the medial end –15-20% occur at distal end

•Fx which leaves the coraco-clavicular lig intact are

much more stable and more likely to heal •Exuberant callus formation of clavicle fx may cause thoracic outlet syndrome

Clavicle fracture Clavicle fracture

•12 yr old boy with history of trauma to shoulder 2-3 weeks ago

Elbow fractures

•Radial head fx is most common adult elbow fracture –Take oblique view in addition to AP/lat!

•Remember- the posterior fat pad is NOT normally visible on the lateral x-ray

–In child with hx of trauma this is a reliable sign of fracture

Normal elbow alignment

•Radiocapitellar line: Normally, a line through neck and midpoint of

radial head should pass through the capitellum in all projections. •Anterior humeral line: Line along the anterior humeral cortex on a lateral elbow projection should intersect the middle 1/3 of capitellum.

Trauma- Fat pad sign

•Visiblity of the posterior fat pad in a pediatric patient with a history of trauma is strongly indicative (90%+) of fracture •Visibility of anterior fat pad is normal- but displacement is not!

•No obvious fx, but visible posterior fat pad (positive fat pad sign) and displaced anterior fat pad (“sail sign”)

Trauma-

•Ulnar fracture with radial head dislocation

Trauma- supracondylar #

•Initial exam (left) somewhat light; fracture more easily seen on darker repeat lateral

Trauma- supracondylar # •Abnormal anterior humeral line

Radial head fx Radial head fx Elbow fractures

•Supracondylar fracture is most common pediatric elbow

fracture •Injury to the brachial artery or median nv. may occur with significant displacement

Nursemaid’s elbow

•Eponyms: Goyrand's injury / Malgaigne's luxation •Mechanism: subluxation of radial head distally to annular ligament

such that the lig. becomes interposed between the capitellum and radial head. •Typically occurs when small child is lifted forcibly by axial distraction on forearm. •Occurs before the radial head is fully developed (prior to age 6 ) •Most common at age 2; not common after age 8.

•Clinical presentation

–.Rubbery resistance to passive supination and extension of elbow. –Arm held in flexion approx. 20 degrees and slight pronation.

• Treatment: reduction without anaesthesia by anteriorward pressure on radial head with thumb as elbow is slowly extended and supinated; occasionally, flexion and pronation of elbow may also be needed. •X-rays are negative

Forearm fractures •Monteggia fx

–Fx of ulna with dislocation of radial head –This example is a non-united Monteggia fx in a patient with a who gave a history of “recent trauma”

Forearm fractures •Monteggia fx

–Pediatric patient (right) –Adult patient (below)

Forearm fractures •Galeazzi Fracture

–Fx of radius with diastasis of the distal radio-ulnar joint (two different cases)

Wrist injuries

•Distal radius or ulna fx 10X more common than carpal bone fx. •Colle’s fx

–Fx. distal radial metaphysis with dorsalangulation –+/- intra-articular involvement –Assoc. ulnar styloid fx often due to attachment of triangular cartilage

–Usually cause is fall on outstretched hand

Colle’s fx

•Note- even with the impacted fx, the distal radial articular surface has lost normal volar slant (see below diag)

•Force applied thru TFCC to ulnar styloid may cause avulsion injury in Colles fx.

Wrist injuries •Colle’s fx

–Fx. distal radial metaphysis with dorsalangulation –+/- intra-articular involvement –Assoc. ulnar styloid fx often due to attachment of triangular cartilage –Usually cause is fall on outstretched hand

Wrist injuries •Smith’s fx

–Fx distal radius with palmar displacement –Articular surface not involved (case below most likely does have articular involvement)

Wrist injuries •Barton’s fx

–Fx of the dorsal rim of the radius due to impaction of carpus •Barton originally described either dorsal or palmar rim fx –By definition, an intra-articular fracture –Carpus is dislocated or subluxed in addition to fracture

Wrist injuries •Barton’s fx

–Equivocal plain film (right) –T1 MR demonstrates definite loss of signal due to edema and linear

Wrist injuries

•Both bones fracture distal forearm

–Distal radial meta-diaphysis # with posterior displacement –Salter-Harris # distal ulna with posterior displacement (?Type I or II?)

Wrist injuries •Hutchinson fx

–Fx radial styloid process

–Involves the articular surface –AKA “Chauffeur’s fx” –Brachioradialis m. inserts on the radial styloid, therefore usually above elbow cast

Carpal injuries

•Scapholunate dissociation

–Scapho-lunate space >2mm is suspicious and >4mm is diagnostic of rupture of scapho-lunate ligament –“Terry Thomas” sign –Clenched fist view may be useful to emphasize this finding

Carpal injuries

•More recently, the “Terry Thomas sign” has been referred to as the “David Letterman sign”.

Carpal injuries

•Scapholunate dissociation

–Scapho-lunate space >2mm is suspicious and >4mm is diagnostic of rupture of scapho-lunate ligament –“Terry Thomas” sign –Clenched fist view may be useful to emphasize this finding

Ruptured scapholunate ligament

•MR examination is very sensitive for evaluation of the scapholunate ligament

Vascular supply to scaphoid

•Far left shows nutrient foramina along entire length •Types at middle and right have vessels entering distally and running intraosseous course to supply the proximal pole. –More predisposed to AVN if fx thru waist occurs

Carpal injuries- scaphoid fx

•Most commonly fx carpal bone (50-70%) •Reported union rate varies (50-95%) •Prognosis improves with more distal fx, worse if proximal 1/3 •Subtle if not displaced

–fx line at 2 wks may more clearly seen

•Delayed union not uncommon –May take 6 – 12 mos.

Ulnar deviation view of wrist

•Ulnar deviation view may help identify scaphoid waist fx •Scaphoid flexes in radial deviation and transverse fx line better aligned to CR in ulnar deviation •(film below shows positioning- no fracture present

Carpal injuries- scaphoid fx Carpal injuries- scaphoid fx •Scaphoid fracture oblique thru waist

Carpal injuries- scaphoid fx

What x-ray changes suggest a poor outcome?

Carpal injuries- scaphoid fx

•May occur in association with dislocations of carpus,

particularly lunate or perilunate dislocation •“transcaphoid-perilunate fracture dislocation” seen below

Carpal injuries- triquetrum fx

•2nd most common fx •Usually dorsal avulsion injury •Triquetrum normally forms the posterior “horizon” of the mid-carpus on lateral film; look here for fx.

Perilunate dislocation

•Dislocation of carpus from lunate- this case has associated # radius •Note the position of the lunate/capitate on lateral view •“pie-shaped” or triangular appearance of lunate on PA view

Carpal injuries- DISI and VISI

•DISI = dorsal intercalated segment instability •VISI = volar intercalated segment instability •Both defined by the relationship of the lunate to the capitate •Scapho-lunate angle is altered in either deformity

Carpal injuries- DISI and VISI

•Scapho-lunate angle is typically 30-60 degrees

–Note- scapholunate angle changes with lateral flexion

•In DISI, the lunate rotates posteriorly, and/or scaphoid anteriorly, causing increased scapho-lunate angle •Usually assoc with rupture of scapho-lunate ligament

Carpal injuries- DISI and VISI

•In VISI, the lunate rotates anteriorly, and/or the scaphoid

rotates posteriorly, causing decreased scapho-lunate angle •Usually assoc with rupture of the lunate-triquetral ligament or mid-carpal sprains

Vascular complication of trauma“Keinbock’s Disease”

•Keinbock’s disease = Avascular necrosis of lunate •Typical hx of trauma, either chronic repetitive or acute- fx not necessary •Inc. density and fragmentation of lunate •Presence of ulna minus variant predisposes to Keinbocks

Vascular complication- Keinbock’s •Increased radiopacity and beginning osteophyte formation •Predisposes to premature DJD

Hand injuries – Bennett’s fx

•A fracture-subluxation of the first carpo-metacarpal

articulation •Typically, an oblique fx thru the base of the 1st MC base •The 1st MC becomes unstable and displaces proximally and into flexion –Usually internal fixation used to stablize

Hand injuries – Rolando fx

•A comminuted Bennett fracture; same mechanism and management apply

Hand injuries – Gamekeeper’s Thumb •Abduction force to the 1st MCP articulation causes avulsion of the

base of the proximal phalanx •Ulnar collateral lig. may rupture without fracture = neg plain film!

Gamekeeper’s Thumb (ski-pole thumb)

•Fragment is retracted a significant distance from the injury in this case

•This injury may be acquired from skiing = “ski-pole thumb”

Gamekeeper’s Thumb (ski-pole thumb)

Films below right and left thumbs of same patient- injuries not acute at time of films

Hand injuries – Metacarpal fx •Fractures of the distal (neck) portion are common –“Bar room” or “boxer” fractures

•Palmar angulation common

–More acceptable in neck portion of MC; not good in diaphysis

•If fingers overlap on flexion, then rotational malpostion inferred –Malrotation not acceptable

Boxer Fracture Hand injuries – Metacarpal fx

•Midshaft MC fracture with pin to avoid flexion deformity

Injuries of the pelvis

•Pelvis is stable unless the pelvic ring is broken/separated in two places •Stable injuries include

–Avulsion fractures (see next slide) –Isolated iliac wing fracture (not into pelvic opening) –Single ramus fracture of obturator foramen –Horizontal fracture of sacrum –Dislocation and/or fracture of coccyx

•Monitor sacral and coccygeal fracture for neurological injury

Pelvic fracture

•Anterior fractures acetabulum and pubic ramus •Posterior fracutre is ……..

Pelvic fx diagragm Avulsion injuries of the pelvis •Common sites

–ASIS – sartorius muscle –AIIS – rectus femoris muscle –Ischial tuberosity – hamstring muscle

•Stable injuries, typically managed conservatively

Avulsion injuries of the pelvis •Avulsions of AIIS (left) and ASIS (right)

Avulsion injuries of the pelvis •Old avulsions of ASIS

Avulsion injuries of the pelvis •Avulsion of ischial tuberosity

Pubic Symphysis

•Diastasis may occur due to multiple childbirth •Case below is 39 yr. old female with 10 children- note the wide symphysis pubis

Stress fracture of pelvis

•In osteoporotic patients who begin walking program, stress fracture may develop in pelvis

Slipped Femoral Capital Epiphysis •Separation thru the proximal femoral physis •Easily overlooked! –May present with “knee” (lower thigh) pain

•Age: peak in late childhood/early adolescence

•Sex: Males > Females approx. 2:1 •Left hip > right hip, but bilateral in 20-30% –Females more commonly bilateral

•Avascular necrosis may occur as complication

S F C E – x-ray

•Blurring, irregularity of metaphyseal border of physeal plate •Widening of physis •Klein’s line does not intersect FCE –Klein’s line along lateral femoral neck should intersect small portion of FCE on both AP and frogleg views

S F C E – x-ray

•Apparent dec. height of FCE

–Due to posterior, medial and inferior displacement of FCE

•Loss of Capener’s triangle

–overlap of medial metaphyseal margin over acetabulum

•Decreased height of FCE

SFCE Proximal femoral fractures •Types

–intracapsular –extracapsular

•Intracapsular

–subcapital- most common type –mid-cervical –Basicervical

•Extracapsular

–intertrochanteric –subtrochanteric –trochanteric –May be difficult to see

When to x-ray? Ottowa Rules •Investigators in Ottawa conducted a retrospective

chart review of all patients with acute knee injuries who presented to an emergency department over a 10-month •The knees of 74 percent of these patients were evaluated radiographically, but only 5.2 percent were found to have fractures..

When to x-ray? Ottowa Rules •Age •gender • mechanism of injury

–(blunt trauma or fall versus twisting)

•Effusion •ligamentous instability, and pain on palpation. •history of swelling •history of deformity •ability to ambulate (i.e., to walk four steps) •Swelling •decreased range of motion

Ottawa Rules- X-ray if….

•Age 55 years or older with hx blunt trauma •Tenderness at head of fibula •Isolated tenderness of patella •Inability to flex knee to 90 degrees •Inability to walk four weight-bearing steps

immediately after the injury and in the emergency department Subsequent studies have shown these rules to be nearly 100% sensitive, but may show significant false positives.

•Blunt trauma or a fall as mechanism of injury plus either of the following:

–Age younger than 12 years or older than 50 years –Inability to walk four weight-bearing steps in the emergency department

•In a 1996 prospective study, the Pittsburgh decision rules

were 99 percent sensitive (were positive when fracture was present) and had a positive predictive value of 24% (fracture was present when positive findings present ). (JAMA 1996;275:611-5)

Trauma- plain film findings

•Tibial plateau fractures are most common of proximal tibial fractures •Bone injuries often accompanied by cartilage/ligament injury •Varus/valgus stresses applied to knee result in compression force to tibial plateau on one side with distraction force to ligaments on contalateral side

Trauma- plain film findings

•Films (from Greenspan) show 30 yr. old alcoholic struck by a car with a wedge fracture of the lateral tibial plateau •Laterally applied force creates inferior vector on lateral tibial plateau

Trauma- plain film findings

This series (also from Greenspan) shows depressed lateral plateau fx on 38 yr. old struck by a car. Cross-table lateral shows the fat-blood interface resulting from intraarticular extension of fx. (FBI sign)

Segond fracture

•Avulsion force to the insertion of the iliotibial band can result in detached fragment

Segond fracture

•Avulsion force to the insertion of the iliotibial band can result in detached fragment

Spine trauma Canadian C-rule for radiography 3 steps •1st- Are there high risk factors that mandate

x-ray?

–Age >/+65 –Dangerous* mechanism –Paraesthesia of limbs

•*Dangerous mechanism

–Fall from 100km) MVA, rollover or ejection –Mechanized recreation vehicle –Bicycle collision

Canadian C-rule for radiography

•2nd- Are there any low risk factors that allow ROM to be checked? –Simple rear-end MVA* –Sitting position in ER –Ambulatory at any time –Delayed (ie, not immediate) onset of pain –Absence of midline neck pain

•If any of above present, then check ROM before x-ray •*Simple rear-end MVA excludes –Pushed into oncoming traffic –Collision with large truck or bus –Hit by high speed vehicle –Rollover

Canadian C-rule for radiography •3rd- Check ROM

–If patient can actively rotate head/neck 45 to both right and left, then no x-ray recommended –If cannot demonstrate 45 degrees rotation to both right and left, xray recommended

•Note- this study did not overlook “significant” injuries to

cervical spine, however avulsion fractures and compression injuries of <25% were not considered to be of significance for this study, since they are managed conservatively

Spine trauma- stable vs unstable

•Stable = further limited motion unlikely to be associated with significant neurological injury.

•Unstable = risk of neurological injury is high if further motion is permitted. •Stable injuries C-spine

–Post arch fx C1 –Simple wedge fx –Unilateral facet dislocation –Subluxation

•Unstable injuries C-spine

–Teardrop fx (flexion or extension type) –Dens fx –Burst (Jefferson) fx C1 –Hangman fx (C2 pedicles) –Bilateral facet dislocation

AMA guidelines for loss of motion segment integrity •Cervical spine

–Motion segment demonstrates axial axis rotation (ie, flex/ext) that is more than 11 degrees in excess of the rotation of both of the adjacent motion segments –A-P translational displacement > 3.5mm

•Lumbar spine

–A-P translational displacement > 5mm

3 columns of thoracolumbar spine •Anterior column

–Anterior 2/3 of body and disc

•Middle column

–Posterior 1/3 of body and disc, including the PLL and annular disc fibers

•Posterior column

–Posterior elements (Zygopophyseal jnts and capsules, neural arch, lig. flavum, infra- and supraspinous ligaments

Cervical spine trauma • SOFT TISSUE SIGNS:

•Wide retropharyngeal space (should be <7mm at C2 level) •Displaced prevertebral fat stripe •Tracheal deviation a/o laryngeal dislocation •Wide retrotracheal space- normals should be: –< 23 mm at C6 level for adult –< 14 mm at C6 level for child

C-spine: injury vs mechanism •HYPEREXTENSION

–Hyperextension Hyperextension dislocation –Avulsion fx of the anterior arch of atlas –Extension teardrop fracture of the axis –Fracture of the posterior arch of atlas –Laminar fracture

•Traumatic spondylolisthsis (Hangman's fracture) –A fracturefracture-dislocation type injury

•LATERAL FLEXION

–Uncinate process fracture

C-spine: injury vs mechanism •HYPERFLEXION

–Anterior subluxation (hyperflexion sprain) –Bilateral interfacetal dislocation –Simple wedge compression fracture –Clay shoveler's fracture –Flexion teardrop fracture

• SIMULTANEOUS HYPERFLEXION AND ROTATION –Unilateral interfacetal dislocation (locked vertebra) vertebra)

•SIMULTANEOUS HYPEREXTENSION AND ROTATION –Pillar fracture

•VERTICAL COMPRESSION –Jefferson bursting fracture –Burst fracture

•INJURIES CAUSED BY DIVERSE OR IMPRECISELY UNDERSTOOD MECHANISMS

–AtlantoAtlanto-occipital dissociation (ext/flex) –Odontoid fractures

ABNORMAL VERTEBRAL ALIGNMENT

•Loss of lordosis secondary to m. spasm •Acute kyphotic angulation

–May be related to rupture of nuchal, interspinous and or capsular ligaments

•Traumatic torticollis •Widened interspinous spaces •George's line abnormal •Vertebral body rotation

–M. spasm may cause –Unilat. facet dislocat'n may cause –Hyperext./flex. # dislocation may cause

•Atlantodental interspace widening >3mm for adult > 5mm for child

•Lateral mass overhang

–1-2mm OK for infants –>6.9mm combined = t’ t’verse lig ruptured

ABNORMAL JOINTS

–Widened apophyseal joints –Widened Atlantoaxial joints –Abnormal disc

–LUCENT CLEFT SIGN •May only be visible on the extension projection •Difficult to d/dx from degenerative vacuum phenomenon

DISTRIBUTION OF CERVICAL SPINE INJURIES

•C1 - 6% •C2 - 27% •C3 - 10% •C4 - 10% •C5 - 18% C7 - 18% • C6 - 27%

JEFFERSON FRACTURE

–Bilateral fractures thru the anterior and posterior neural ring of atlas –May be associated with lateral displacement of the lateral masses and transverse ligament disruption. –Results from compression force –Low incidence of neurological injury –Usually treated with conservative immobilization. –Look for combined overlap >/= 7mm; indicates t'verse lig. rupture. –Associated spine #’s in 24-48%- check other areas carefully!

•Normal alignment of C1-2 on APOM- no significant

overhang of lateral masses relative to C-2 facet margin

JEFFERSON FRACTURE C-1 posterior arch fracture

•Hyperextension traps thin C-1 arch between occiput and large posterior arch C-2 •Usually stable injury

Atlanto-occipital dissociation

•Not common- less than 1% of all acute c-spine injuries

•Commonly with neurological deficit or fatal •Powers ratio

–Line from basion to junction line of C1 posterior arch = BC –Line from opisthion to anterior arch C1 (posterior cortex) = AO –BC/AO should not be greater than 1.15

C-2 fracture- “Hangman” type

•Bilateral fracture thru pedicles •More likely flexion-type injury; maybe extension

C-2 fracture- “Hangman” type

•CT imaging shows fracture and “perched” facets C2/3

Columns of the spine

•Anterior column is ALL, anterior 2/3 vertebral body and anterior ½ of IVD •Middle column is posterior 1/3 body, back to and including the PLL •Posterior column is posterior arch and ligaments

•Single column injury is usually stable •Two column injury is usually unstable •Three column injury is unstable