Fractures UE Flashcards
mechanisms of injury
- unloaded
- tension
- compression
- bending
- shear
- torsion
- combined loading
primary healing of fracture
- end-to-end fracture contact
- no callus formation
- healing in the intramedullary canal (ENDOSTEAL)
- visible on xray after months
- secondary to rigid fixation
- compression plating
secondary healing of fracture
- no fracture compression
- callus formation
- healing is OUTSIDE intramedullary canal (PERIOSTEAL)
- callus/bridging callus can be seen in xray after 2 weeks
- micromotion present
- casting, intramedullary nailing, neutralization plating
inflammation stage of fracture healing
- day 1-14
- blood vessels torn -> hematoma formation
- activated platelets release products and cause influx of inflammatory cells
- subperiosteal and endosteal cell proliferation
products released by activated platelets and cells of repait
- fibronectin
- pdgf
- tgf-b
- fibroblasts, endothelial cells, osteoblasts
- macrophages and neutrophils
- osteoprogenitor cells
repair stage of fracture healing
- 2nd to 6th week
- initiation of healing through restoration of blood supply to unite fracture fragments
what is soft callus formation
- osteoblasts form a bridge of woven bone over fracture site which provides support
- formation of connective tissue and angiogenesis = FIRST RADIOGRAPHIC SIGN of reuniting bones
remodeling stage of fracture healing
- consolidation
- woven bone is replaced by compact lamellar bone
- osteoclastic resorption + osteoblastic deposition
principles of fracture treatment
- restore articulating surface (only 2 mm displacement allowed)
- rigid fixation
- allow early range of motion
shoulder trauma is composed of __
clavicle, scapula, proximal humerus
t/f muscle attachments allow motion and don’t cause deformity when fractured
false, when fractured, muscles act as deforming force resulting in displacement
parts of the shoulder joint
- scapula: rotator cuff origin, fractured in high energy trauma
- proximal humerus: rotator cuff insertion
common sites of fractures on shoulder
- body of scapula
- spine of scapula
- glenoid
- coracoid process
first bone to ossify at 5th fetal week, and last to fuse at 25 years
clavicle
displacement due to clavicle in fractures
medial end is pulled inferiorly, lateral end is puller superiorly
t/f the longer the lever arm, the easier it is to perform range of motion
true, shortening = dec function because of dec in length of lever arm (more effort needed for elevation)
critical length for lever arm
2-2.5 cm
clavicular third fractures
- middle!!: allowable displacement of 2 cm shortening
- lateral: depending on location of fracture to coracoclavicular ligament
- medial: least common, only posterior displacement needs emergency surgery
absolute indications for fracture fixation
- open fractures
- skin tearing
- vascular injuries
relative indications for fracture fixation
- shortening more than 2 cm
- delayed union leading to nun-union within 3 mos
types of lateral third fractures
- type 1 and 3 are non-surgical
- type 2 is surgical
- fracture that displaces medial fragment superiorly = coracoclavicular ligament is torn
- coracoclavicular ligament= main stabilizer against vertical displacement
treament for clavicle fracture
- restores length/position to permit healing and maintain lever arm position
- internal fixation using intramedullary nail
- plates and screws
deformations from proximal humerus
- subscapularis = internal rotation
- infraspinatus and teres major = external rotation
- supraspinatus = abduction of shoulder
majority of rotator cuff muscle insertions are in __
greater tuberosity of proximal humerus
