Principles II Flashcards
Transverse fracture
Those that run across the axis
Oblique fracture
Fracture which goes at angle to axis
Spiral fracture
Runs around axis of bone
Comminuted fracture
Many relatively small fragments
Avulsion fracture
Piece of bone attached to tendon or ligament is torn away
Displaced
Parts of bone break and move from place and don’t remain correctly aligned
Non-displaced
Crack or break in bone remain in alignment and don’t move from their place
Periosteal injury
Direct blow, bleeding under periosteum
e.g. tibia from kick
Bone remodelling happens when
In response to stress
Wolff law
Bone remodels in direct response to the forces applied
Osteoclasts
Resorption
Osteoblasts
Deposition
Stress fracture process
When bone’s reparative capacity is overwhelmed by chronic overload, damage can begin to accumulate, and if allowed to progress this multifactorial process can lead to stress fracture
Bone overuse
Increased osteoclastic activity at sides of bone stress or strain may cause transient weakening of the bone locally, predisposing to microdamage
Unless given appropriate time for healing and osteoblastic mediated bone deposition, adjusting sites of microdamage are thought to coalesce, giving rise to sites of stress reaction or injury
At this stage may be minimally symptomatic, and if do plain film radiograph may appear normal. If patient does not rest with progressive overload the bone becomes increasingly vulnerable and patient develops symptoms that are thought to reflect extent of underlying bone injury
–> if uninterrupted, may develop into stress fracture
Stress fracture
Microfracture due to repetitive loading that, over time, exceeds the bone’s intrinsic ability to repair itself
2 mechanisms for overload
Impact forces
Muscle pull
Impact forces example
Metatarsal in marching
Muscle pull example
Neck of femur in female marathon runners
Fatigue stress fracture
Normal bone unable to keep up with repair when repeatedly damaged or stressed- normal bone, abnormal stresses
Insufficiency stress fractures
Under normal strain, but structurally abnormal because of metabolic bone disease or osteoporosis
Abnormally or weakened bone but normal stress
Stress fractures can occur in
Sedentary people who suddenly take up exercise, may also occur in athletes completing high volume high impact training e.g. running or jumping sports
Also reported in soldiers who march long distance
Where do stress fractures usually occur
Weight bearing bones
Tibia, metatarsals and navicular
Less common stress fracture areas
Femur
Pelvis
Periostitis definition
Inflammation of periosteum (tendon attachment)