trauma Flashcards
innervation of subscapularis?
upper and lower subscapular nerves (derived from POSTERIOR cord of brachial plexus)
innervation of biceps brachii?
-musculocutaneous nerve (derived from lateral cord)
innervation of pectoralis major?
-medial and lateral pectoral nerves (derived from the medial and lateral cords, respectively)
innervation of rhomboid major?
-dorsal scapular nerve (derived from the C5 nerve root)
innervation of supraspinatus?
-suprascapular nerve (derived from upper trunk)
necrotizing fasciitis
- delay in time of diagnosis associated w/ poor outcomes!
- most commonly polymicrobial infection, w/ group A B-hemolytic strep the most common bacteria
- tx: emergent aggressive debridement of all involved tissues and immediate empiric antibiotics covering aerobic, anaerobic, gram positive and gram negative bacteria
pain in retrograde vs antegrade femoral nails?
retrograde: knee pain
antegrade: hip pain, abductor weakness, and heterotopic ossification of the abductors
- Tornetta et al: more problems of length and rotation using a retrograde nailing
what % of the proximal radial head articulates w/ the proximal ulna?
- 75%
- remaining 25% is considered the “safe zone” and is important for placement of fixation
- nonarticulating portion of radial head consistently encompassed a 90 deg angle localized by palpation of the radial styloid and Lister’s tubercle
during the saline injection load test to diagnose traumatic knee arthrotomies, how much saline needs to be injected to diagnose 99% of knee arthrotomies?
175mL
- note the clinical exam alone can NOT be relied on to detect traumatic arthrotomies alone
- an inferoeromedial injection location requires significantly less fluid than a superomedial injection location
pathway of the axillary nerve within the brachial plexus
-C5-C6 nerve roots–> upper trunk–> posterior division–> posterior cord
Quadrilateral space syndrome
- condition defined by axillary nerve, +/- posterior humeral circumflex artery compression in the quadrilateral space
- most commonly affects the dominant shoulder in overhead movement athletes or other throwing athletes
- exam may reveal weakness w/ the arm positioned in abduction and external rotation
- in long standing compression, there may also be atrophy of the teres minor and deltoid muscle
course of the musculocutaneous nerve through the brachial plexus
-C5-C7 nerve roots–> upper/middle trunks–> anterior division–> lateral cord
course of the suprascapular nerve through the brachial plexus
-C5-C6 nerve roots–> upper trunk
course of the long thoracic nerve through the brachial plexus
-C5-C7 nerve roots
course of the ulnar nerve through the brachial plexus
-C8-T1 nerve root–> lower trunk–> anterior division–> medial cord
use of long lateral locking plate to treat tibia fracture has been associated w/ what complication?
superficial peroneal nerve injury
most commonly recommended fixation for comminuted fractures of the olecranon?
Plate fixation
indications for plate fixation of elbow fractures
- comminuted fractures of olecranon
- oblique fx’s distal to the midpoint of the trochlear notch
- fractures that involve the coronoid process
- fractures associated w/ Monteggia fracture-dislocations
indication for tension band wiring in elbow fracture?
best indicated for simple transverse fractures through the midpoint of the trochlear notch
terrible triad injury of elbow
- elbow dislocation (often associated w/ posterolateral dislocation or LCL injury)
- radial head fracture
- coronoid fracture
what is the most common complication following operative fixation of terrible triad elbow injuries?
Loss of elbow range of motion
-this REQUIRES reoperation
protocol of fixation for terrible triad injuries of elbow
- coronoid fracture ORIF (capsular repair)
- radial head fx ORIF or replacement
- LCL complex repair (isometric point is center of capitellum)
- reevaluation of stability; MCL repair or hinged fixator application
at the elbow, the anterior bundle of the medial collateral ligament inserts at which site?
-anteromedial process of the coronoid (sublime tubercle)
what is the FUNCTIONAL ROM of the elbow joint?
30-130
Name the 5 elementary and 5 associated acetabular fracture patterns
Elementary: posterior wall, posterior column, anterior wall, anterior column, transverse
Associated: associated both column, transverse + posterior wall, T shaped, anterior column or wall+ posterior hemitransverse, posterior column + posterior wall
Posterior wall acetabular fracture
- most common
- “gull sign” on obturator oblique view
Posterior column acetabular fracture
- best seen on iliac oblique view
- check for injury to superior gluteal NV bundle
- ilioischial line disrupted on AP view
Anterior column acetabular fracture
-more common in elderly puts with fall from standing (anterior column + medial wall)
Transverse acetabular fracture
- axial CT shows anterior to posterior fracture line
- only elementary fracture to involve both columns
What are factors associated w/ Hoffa fracture of distal femur?
- isolated lateral condyle fracture
- open fracture
most common associated injury for LC type pelvic injuries?
Closed head injury
function of sacrospinous and sacrotuberous ligaments in pelvic floor as it relates to pelvic ring injuries?
Sacrospinous: resists ER
Sacrotuberous: resists shear and flexion
Posterior SI complex (posterior tension band)
- strongest ligaments in body
- more important than anterior structures for pelvic ring stability
- Anterior SI ligaments: resists ER after failure of pelvic floor and anterior structures
- Interosseous ligaments: resists AP translation
- Posterior SI ligament: resists cephalad-caudad displacement
- Iliolumbar: resists rotation and augments posterior SI ligaments
what should you look for on physical exam in pelvic ring injuries?
- position of rest of lower extremities
- leg length discrepancy
- scrotal, labial, or perineal hematoma
- flank hematoma
- lacerations of perineum
- degloving injuries (Morel-Lavallee lesion)
- rule out lumbosacral plexus injuries
- rectal exam (mandatory)
- urogenital exam
- vaginal exam (mandatory)
how do you know when Inlet view of pelvis is adequate?
when S1 overlaps S2 body
-idial for visualizing AP translation of hemipelvis, IR or ER of hemipelvis, widening of SI joint, sacral ala impaction
how do you know when outlet view of pelvis is adequate?
when pubic symphysis overlies S2 body
-ideal for visualizing vertical translation of hemipelvis, flex/ext of hemipelvis, disruption of sacral foramina and location of sacral fx’s
radiographic signs of instability in pelvic plain films?
- > 5mm displacement of posterior SI complex
- presence of posterior sacral fx gap
- avulsion fx’s (ischial spine, ischial tuberosity, sacrum, transverse process of 5th lumbar vertebrae)
Young-Burgess Classification
APC, LC, VS, Combined
APC 1
- symphysis widening <2.5cm
- tx: non-op, protected WB
APC 2
- symphysis widening > 2.5cm, anterior SI joint diastasis, posterior SI ligaments intact, disruption of sacrospinous and sacrotuberous ligaments
- tx: anterior symphyseal plate or ex fix, +/- posterior fixation
APC 3
- disruption of anterior and posterior SI ligaments (SI dislocation), disruption of sacrospinous and sacrotuberous ligaments, APC 3 associated w/ vascular injury
- tx: anterior symphyseal multi-hole plate or ex-fix and posterior stabilization w/ SI screws or plate/screws
LC 1
- oblique or transverse ramus fx and ipsilateral anterior sacral ala compression fx
- tx: non-op, protected WB (complete, comminuted sacral component); WBAT (simple, incomplete sacral fx)
LC 2
- rami fx and ipsilateral posterior ilum fx dislocation (crescent fracture)
- tx: ORIF of ilium
LC 3
- ipsilateral LC and contralateral APC (windswept pelvis); common mechanism is rollover vehicle accident or peds vs auto
- tx: posterior stabilization w/ plate or SI screws as needed; percutaneous or open based on injury pattern and surgeon preference
Vertical shear pelvic ring injury
- posterior and superior directed force; associated w/ the highest risk of hypovolemic shock (63%); mortality rate up to 25%
- tx: posterior stabilization w/ plate or SI screws as needed; percutaneous or open based on injury pattern and surgeon preference
Absolute vs relative stability
absolute: alignment and compression across fx site resulting in no micromotion at physiological loads, primary bone healing via cutting cones, no callus
relative: some degree of motion exists at fx site which is reversible (elastic) allowing for mechanical stimulation of bone healing, secondary bone healing via callus
5 functions of a plate
Compression: compression at fx site utilizing oblique screw holes in plate and placing screws eccentrically, primary bone healing
Neutralization: used to “protect” lag screw fixation or another absolute stability construct
Buttress: creates a stable shoulder w/ intact bone to resist shear forces. Usually found in peri-articular fxs and results in primary bone healing
Tension band: converts distractive forces into compressive forces by its orientation, primary bone healing
Bridge: used to span an area of comminution and is a relative stability construct (overall length, alignment, and rotation needs to be restored)
modulus of elasticity
describes deformation of a material to a certain amount of force. It is the SLOPE OF THE STRESS-STRAIN CURVE. Stiffer materials (stainless steel) have a higher modulus of elasticity while more flexible materials (titanium) have a lower modulus of elasticity.
stages of fracture healing and how long each lasts
3 stages: inflammation, repair, and remodeling
inflammation: time of initial injury and fx hematoma formation to 2 wks
Repair: soft callus to hard callus, 2 wks
Remodeling: lasts between 4-12 wks as woven bone is replaced by trabecular bone
intramembranous ossification vs enchondral ossification in primary and secondary bone healing?
primary: intramembranous
secondary: enchondral
Primary causes of acute compartment syndrome
- Severe trauma associated w/ a fracture or vascular reperfusion of a limb
- prolonged compression on an area by a tourniquet, dressing, or even a pt’s own body weight
- burns
- extravasation of IV fluid or contrast material
- exercise-induced compartment syndrome
how is compartment syndrome diagnosed?
- made entirely based on physical exam in an awake, cooperative patient
- primary finding is increasing pain (often out of proportion to exam and non-responsive to pain meds)
- pain w/ passive stretch (most sensitive)
- other signs include paresthesias, pallor, paralysis, pulselessness, and poikilothermia (late findings)
at what pressure does acute compartment syndrome exist?
generally agreed that absolute pressure exceeding 30mmHg or when pressure is within 30mmHg of DIASTOLIC blood pressure
can compartment syndrome exist in setting of an open fx?
Yes. The open wound may help decompress one compartment, but the other fascial compartments can still be affected
tx of acute compartment syndrome?
emergent surgical decompression OF ALL COMPARTMENTS of the limb (single or double incision in lower leg; anterolateral and posteromedial incisions). The skin wounds are then left open until they are closed or skin grafted at a later time
What is an important aspect of post-op care of a patient who has developed compartment syndrome?
if muscle ischemia and/or death has occurred, myoglobinuria may result. Hydration and monitoring of renal function (BUN and creatinine) should be performed
what is the proper initial management in compartment syndrome?
initially, all constrictive dressings should be loosened or removed. Then perform a full neurovascular exam. Many would advocate for fasciotomies if there is clinical concern for the diagnosis.
what are the compartments in the lower leg?
4 compartments: anterior, lateral, deep posterior, superficial posterior
what are the compartments in the forearm?
3 compartments: volar, dorsal, mobile wad
what are the compartments in the hand?
10 compartments: one for each of the four dorsal interossei, three for the volar interossei, and one each for the ADDuctor pollicis, thenar muscles, and hypothenar muscles
what are the compartments in the foot?
exact number is debated (as many as nine), but most would agree that there are four distinct compartments: an intrinsic, medial, central, and lateral compartment
What is the proper starting point for a trochanteric entry nail for femoral shaft fracture?
the proper starting point for a trochanteric nail is just lateral to the long axis of the femur. Depending on the patient’s anatomy, this can vary between just medial and just lateral to the tip of the greater trochanter. On the lateral view, the starting point is colinear with the long axis of the femur.
What is optimal tx for vertical shear (Pauwels 3) type femoral neck fractures in relatively young pts?
Sliding hip screw w/ side plate is superior to cannulated screw fixation (lower rates of nonunion)
What is the proper starting point for retrograde IM nail of femoral shaft fractures?
Proper technique includes an insertion site in the intracondylar notch at the apex of the Blumensaat line, which is approximately 1 cm anterior to the posterior cruciate ligament origin. With this as the starting point, the trajectory for nail insertion should be colinear with the long axis of the femur in both the anteroposterior and lateral planes. At least two distal interlocks should be used to minimize the risk of secondary telescoping of the nail into the knee joint
what is the “spur sign” in acetabular fractures?
Best seen on obturator oblique view, It represents a spike of bone from the intact hemipelvis and no articular surface remains with the hemipelvis, which defines the associated both column fracture. The weight-bearing surface of the acetabulum is displaced with the femoral head. In all other patterns, at least part of the articular surface remains with the intact hemipelvis.
what is the most important structure for preventing AP displacement of the sternoclavicular joint?
Posterior sternoclavicular joint capsule
Is IMN an example of absolute or relative stability?
Relative stability
what is the most important factor in achieving a satisfactory outcome following surgery for an ankle fracture?
anatomic alignment (quality of the reduction)
what additional imaging study is recommended for a spiral distal third tibia fracture besides tib/fib plain films?
CT scan of ankle;
Spiral distal tibia fractures are frequently associated with intra-articular fracture extension, usually involving the posterior malleolus. This may or may not be visible on the radiographs. A CT scan of the ankle is recommended to identify this associated injury. This is especially important when considering intramedullary nail fixation of the distal tibia fracture because a previously nondisplaced intra-articular fracture may become displaced as the nail is inserted to its final depth. Anteroposterior screw fixation prior to nailing may be useful in these cases
what is the most common complication following surgery for a “terrible triad” elbow fracture-dislocation?
Restricted elbow ROM is almost always present
what are factors that are predictive of osteonecrosis of the humeral head after fracture?
Factors shown to be predictive of osteonecrosis include: fractures consisting of four fragments, angular displacement of the head (greater than 45 degrees ), the amount of displacement of the tuberosities (displacement of greater than 10 mm), glenohumeral dislocation, and head-split components. Factors associated with good prognosis include: length of the metaphyseal head extension (calcar segments of greater than 8 mm), the integrity of the medial hinge, and the basic fracture pattern. When the above criteria (anatomic neck, short calcar, disrupted hinge) were combined, positive predictive values of up to 97% could be obtained for osteonecrosis. However, the degree to which this osteonecrosis impacts long-term outcome is unclear and should not be the only indication for proximal humeral arthroplasty.
How often is acute carpal tunnel seen after distal radius fractures?
5-8%
Acceptable criteria for non-op treatment of diaphyseal humerus fractures?
- < 20 deg AP angulation
- < 30 deg varus/valgus angulation
- < 3cm shortening
Note that proximal 1/3rd long oblique fx’s are at greatest risk for nonunion after functional bracing. Also, radial nerve palsy is NOT a contraindication to functional bracing.
how do you treat an adult both bone forearm fx in almost all cases, regardless of angulation?
ORIF of both the radius and ulna
plate fixation of clavicle fx’s compared to non-op tx?
- lower nonunion rate
- higher cost
- higher rate of implant-related complications and subsequent surgery
what is the most cost-effective management strategy for clavicle fractures?
non-op tx w/ delayed surgery in the setting of nonunion
how do you managed supracondylar fx w/ pink pulseless hand before and after CRPP?
splinting and observation in the hospital
management of displaced supracondylar fx w/ absent pulse
- adequate perfusion?–> reduce fx and pin, observe if cap refil, temp, and color indicated adequate perfusion–> admission for vascular obs w/ elbow in relaxed position of approx 45 deg
- pulseless extremity, inadequate perfusion?–> reduce fx and pin–> if hand is pink and pulseless, then admit for vascular obs as above; if hand remains dysvascular, then explore and repair artery via anterior approach (monitor for compartment syndrome, consider fasciotomy)
how do you manage an acute posterior SC dislocation?
attempt closed reduction in the OR w/ vascular surgery on back-up
most common site of comminution in a high energy femoral neck fx in young adult?
Posterior and Inferior
what factor is most important in regard to treating young adult femoral neck fxs?
quality of reduction (largest impact on fx healing and clinical outcomes)
2 most common approaches to ORIF of femoral neck fracture?
- Watson-Jones (anterolateral approach to hip)
- Heuter (distal limb of smith-peterson anterior approach to hip)
Necrotizing fasciitis
- Sx: red or purple skin w/ severe pain, fever, and vomiting
- Dx: surgical exploration in setting of high suspicion; may also use LRINEC score (CRP, WBC, Hgb, Na, Cr, glucose)
- Most common organism is POLYMICROBIAL INFECTION (though group A strep is most common in monomicrobial nec fasc)
- often associated w/ diabetes
5 indications for surgical intervention of tibial plateau fx?
- > 3mm articular step off
- > 5mm condylar widening
- > 10 deg var/valg laxity
- any medial plateau component
- bicondylar fx’s
when should you obtain advanced imaging of a significantly displaced bicondylar tibial plateau fx?
Probably after application of a knee-spanning ex-fix. This allows for ligamentotaxis to reduce the fx fragments and allow for better delination on CT imaging
non-op indications for distal humerus fx’s?
non-displaced Milch Type 1 fx’s (immobilize in supination for lateral condyle fx’s, and pronation for medial condyle fx’s)
how to treat ligamentous Lisfranc injuries?
Open reduction and ARTHRODESIS of the medial 2 tarsometatarsal joints (equivalent functional outcomes and decreased rate of hardware removal or revision surgery compared to primary ORIF)
how to treat bony Lisfranc injuries?
most often ORIF is any evidence of instablity (>2mm shift)
Non-op indications for Lisfranc injuries
-no displacement on WB and stress radiographs and no evidence of bony injury on CT
5 critical radiographic signs to look for with suspicion of Lisfranc injury
- disruption of line from medial base of second metatarsal to medial side of middle cuneiform
- widening of interval between first and second ray
- medial side of base of fourth metatarsal does not line up w/ medial side of cuboid on OBLIQUE VIEW
- metatarsal base dorsal subluxation on LATERAL VIEW
- disruption of the medial column line (line tangential to medial aspect of the navicular and the medial cuneiform)
Ideal starting position for a tibial IMN?
- medial upslope of lateral tibial spine
- anterior lip just anterior to articular surface on lateral view
criteria for septic shock
sepsis w/ persisting hypotension requiring vasopressors to maintain MAP > 65 mmHg and having serum lactate > 2mmol/L despite adequate volume resuscitation
how to assess syndesmotic instability after ORIF ankle fx?
-assess either through open visualization or by comparing closed reduction parameters (clear space, overlap, and fibular position on lateral view) w/ the patient’s contralateral side (assuming no injury)