Case 9 - Extra and PBL Flashcards
what is runners knee
patellofemoral pain syndrome
what causes a runner’s knee
a kneecap that is too high in the knee joint
weak thigh muscles
tight hamstrings
tight achilles tendons
poor foot support
walking or running with the feet rolling in while thigh muscles pull the kneecap outward
excessive training or overuse
injury
what are the symptoms of runner’s knee q
pain in and aorta d the kneecap that happens when you are active or pain after sitting for a long time with the knees bent. this sometimes causes weakness.
rubbing, grinding or clicking sound of the kneecap that you hear when you bend and straighten the knee
kneecap that is tender to the touch
how is runner’s knee diagnosed
health history and physical exam
X rays may be needed for evaluation of the knee
how is runner’s knee treated
cold packs
elevating the leg
compression knee wrap
pain meds
stretching and strengthening exercises
arch support in shoes
what is a nocebo
a detrimental effect on health produced by physiological or psychosomatic factors such as negative expeditions of treatment or prognosis
what are the types of acetylcholine receptors at neuromuscular junction
nicotinic not muscarinic
why are ligaments more likely to tear in women
because of oestrogen and relaxin
what can happen in resistance training
muscle fibres can change from type 2a to type 2x
when and why do stress fractures show up on X rays
2-3 weeks after due to callus formation
why should you not take NSAIDs for fracture pain
as need inflammation to repair and for bone remodelling
what does strain gauge do
converts the mechanical strain into an electrical distance change and act as mechanical electrical converters. as a result of this change in resistance, they generate a voltage change proportional to the strain
atypical gait - v important
what is Wolff’s law
Wolff’s Law states that bones will adapt to the degree of mechanical loading, such that an increase in loading will cause the architecture of the internal, spongy bone to strengthen, followed by the strengthening of the cortical layer.
what are the muscles involved in patella femoral pain
vastus lateralis, whcih pulls your patella up and outwards, and the vastus medals oblique which is the only quadricep muscle that pulls your kneecap up and slightly in.
what are the common reasons for weak vastus mescals oblique include
knee injury, post surgery swelling or disuse
what cells are important in maintaining populations of osteoblasts and the repair of a fracture
osteoprogenitor cells
where are osteoprogenitor cells located
in the periosteum and bone marrow (endosteunm)
what do osteoblasts form
the osteoid which is then calcified into bone
process of osteogenesis
osteoblasts secrete collagen molecules and ground substance
collagen molecules combine to form collagen fibres
the resultant tissue is called osteoid (non-calcified bone)
hydroxyapatite crystals form on the collagen fibres. the osteoid is now calcified and this is bone
steps of bone remodelling normally
Recruitment of osteoclast precursors.
These differentiate into mature multinucleated
osteoclast.
Osteoclasts adhere to an area of trabecular bone.
They dig a pit by secreting hydrogen ions and proteolytic enzymes, by a process called osteolysis.
This secretes cytokines such as insulin-like growth factor (IGF)-1 and TGF-β that have been embedded in the osteoid (the unminarilised component of bone).
These cytokines recruit and activate osteoblasts that have been stimulated to develop from precursor cells (osteoprogenitor cells).
Osteoblasts invade the site, synthesising and secreting the organic matrix of bone (the osteoid) and secreting IGF-1 and TGF-β (which become embedded in the osteoid).
The osteoid is then calcified into bone.
Some osteoblasts become embedded in the osteoid, forming terminal osteocytes.
what is step 1 in bone remodelling following a fracture
haematoma formation:
a large blood clot closes off the injured vessels and leaves a fibrous meshwork in the damaged area
what is step 2 in bone remodelling following a fracture
fibrocartilaginous callus formation:
an extensive internal callus organises within the medullary cavity and between the broken ends of the shaft
an external callus forms and encircles the bone at the level of the fracture
what happens to the centre and edge cells in the external callus
at the centre, cells differentiate into chondrocytes and produce blocks of hyaline cartilage
at the edge, cells differentiate into osteoblasts and begin creating a bridge between the bone fragments on either side of the fracture
what is step 3 in bone remodelling following a fracture
bony callus formation (callus ossification):
osteoblasts replace the central hyaline cartilage of the external callus with spongy bone (woven bone)
when this conversion is complete, the external and internal calluses form an extensive and continuous brace at the fracture site
struts of spongy bone now unite the broken ends
the ends of the fracture are now firmly held in place and can withstand normal stresses from muscle contractions
what is step 4 in bone remodelling following a fracture
osteoclasts and osteoblasts continue to remodel the region of fractures from 4 - 12 months
when the remodelling is complete, living compact bone remains
the repair may be as good as new and leaves no indications that the fracture ever occurred, or the bone may be slightly thicker and stronger than the normal at the fracture site
under comparable stresses, a second fracture will generally occur at a different site
