218 - Fractured hip

Question 1

what is an intracapsular hip fracture?

Answer 1

proximal to intertrochanteric line

• femoral head fracture - rare hip dislocations in young
• femoral neck fractures - associated with osteoporosis/malacia in elderly can lead to avascular necrosis of femur head (medial & lateral curcumflex arteries). classification I - incomplete, II - impacted (complete, not displaced), III - partially displaced, IV - completely displaced or comminuted (shattered)

Question 2

what is an extracapsular hip fracture?

Answer 2

involving or distal to intertrochanteric line (TyI non-displaced, TyII displaced

• trochanteric - avulsion of greater/lesser trochanter from femur by muscle in children & young athletes
• intertrochanteric - elderly & women with osteoporosis
• Subtroachanteric - young adults in high energy trauma & elderly in falls with osteoporosis

Question 3

what is FRAX scoring?

Answer 3

10 year fracture risk assessment

Question 4

what is total hip replacement?

Answer 4

For intracapsular fractures - acetabulum replaced, cartilage removed, femur head prosthesis inserted into reshaped femur with cement. FOr sever comminution & severely degenerated joints

Question 5

what is hemiarthroplasty?

Answer 5

most common for intracapsular fractures - acetabulum kept, head of femur removed and replaced with prosthesis. For patients where risk of AVN is high & older patients who are too unwell for 2nd op

Question 6

how is pinning/canulated screws used in hip fracture?

Answer 6

multiple pins/screws drilled across fracture to hold bone together. for simple neck of femur and young patients with no osteoporosis. risk of AVN must be low

Question 7

how is dynamic hip screws & plate used in hip fracture?

Answer 7

Extracapsular fractures - compression screw drilled into medulla of neck.head of femur and attached to plate on shaft. risk of AVN must be low

Question 8

what is the definition of a fracture, dislocation & subluxation?

Answer 8

• fracture - loss of continuity of substance of a bone due to physical force
• dislocation (luxation) - complete loss of contact between articulating surfaces of a joint
• subluxation - partial dislocation - still some contact between articular surfaces but joint no longer congruous

Question 9

what is the epiphyseal, metaphyseal, diaphyseal levels of bones?

Answer 9

• Epiphyseal - end section
• metaphyseal - neck of bone
• diaphyseal - shaft/mid section of bone

Question 10

what is varus and valgus deformation of bone?

Answer 10

• varus - distal part towards midline

* valgus - distal part away from midline

Question 11

what are the requirements for good fracture healing?

Answer 11

controlled micromovement (stimulates repair) and fracture haematoma (provides stem cells)

Question 12

what are the stages of fracture healing?

Answer 12

• inflammation immediately - fracture haematoma forms containing fibrin clot, platelets, monocytes then later fibroblasts, osteoprogenitors
• soft callus - over weeks when pan& swelling goes - osteoid formed by fibroblasts to produce weak join between fragments. Mast cells, mphages clear debris
• hard callus -weeks/monts - osteoblasts mineralise osteoid into disorganised woven bone incr. stiffness & endochondral/membranous bone forming
• remodelling- months/yrs - woven bone slowly converted to lamellar bone and, excessive callus removed & medullary canal reformed

Question 13

what are the ads & disads of internal fixation of fractures?

Answer 13

needed if gross movement likely, direct bone healing but disperses fracture haematoma

Question 14

what should be done in x-rays for fractures?

Answer 14

2 views right angles, 2 joints above & blow fracture, 2 occasions (apparent after, 2 limbs to compare

Question 15

what are the 3 elements to fracture management?

Answer 15

• reduction - realign bones (closes or open when accurate reduction req & in nerve damage)
• retention - to stabalise either no operative (strappings/sling, plaster, traction) or internal fixation in displaced inta articular fractures, multiple injury, path fractures
• rehabilitation -stop stiffness & start weight bearing

Question 16

what are some complications of fractures?

Answer 16

• malunion, delayed union, non union (after 6mths, hypertrophic good blood supply but insuff stability & atrophic non union no cellular activity)
• joint stiffness *AVN (bone death due to infarction), *myositis ossificans (calcification of soft tissue)
• infection, nerve damage, vascular damage (arteries -pain, pale, paraesthesia, pulselessness, cold venous -swelling haematoma)
• compartment syndrome - muscle swelling with a closed osseofascial compartment causing ↑P, ischemia & infarction of tissues. Signs - out of proportion pain to injury & passive stretch, pins & needles, pulseless
• visceral trauma

Question 17

what is a pathological fracture?

Answer 17

fracture occuring following min stress through abnormal bone - tumours primary myeloma sec mets from breast, bronchus, prostate, kidney,thyroid
infection, osteoporosis/malacia, pagets, osteogenesis imperfecta

Question 18

what is a stress fracture?

Answer 18

due to fatigue - repeated freq forces in normal bone - athletes

Question 19

what do open fractures req?

Answer 19

washout and debridement within 6 hours & stabilisation

Question 20

how are the bones of children different?

Answer 20

have periosteum membrane (thicker & metablolicallt active), more collagen so elastic and porous but weak, epiphyseal plates open (weakness)

Question 21

what is a green stick fracture?

Answer 21

under torsion - outer cortex pulled apart and inner bends due to elasticity but remains intact. can re displace once swelling reduceds

Question 22

what is a buckle/torus fracture?

Answer 22

crushing fracture

Question 23

what is osteoporosis?

Answer 23

a predisposition to skeletal fractures caused by a reduction in total/regional bone mass as calcium hydroxyapatite (makes bone rigid) is reduced. Bone mass decreases after 30-35 yrs (remodelling occurs but lose more). Fractures occur commonly at hip, vertabrae, wrist (colle’s fracture - hands spread on fall). F>M

Question 24

what are the risk factors for osteoporosis?

Answer 24

• family history
• early menopause (progesterone causes ↑osteoblast activity). In younger women due to oestrogen deficiency *sedementary lifestyle (no weight bearing)
• smoking & excess alcohol
• low Ca2+ omtale & sun exposure (↓ vit D)
• medications - thyroxine & steroids
• caucasian *slender build

Question 25

what conditions can cause osteoporosis?

Answer 25

osteomalacia, osteogenesis imperfecta, myeloma, renal failure and endocrine disorders:

• ↑ PTH / hyperparathyroidism - ↑ [Ca2+] in blood due to ↑resorption
• ↑ Calcitonin/hyperthyroidism - C cells of thyroid produce excess calcitonin ↓[Ca2+] in blood so less available for deposition
• cushings - cortisol suppresses osteoblasts & bone growth factors ↓bone deposition
• ideopathic hypercalciuria

Question 26

what investigations should be done on px with suspected osteoporosis?

Answer 26

• investigate for disorders causing 2ry osteoporosis
• Dual energy X-ray Absorpitometry (DEXA) scan - T score is standard deviations from mean peak value for a young adult - normal <-1 indicates bone loss faster than for age

Question 27

what pharmacological treatments are available for the treatment of osteoporosis?

Answer 27

• Ca & vit D (↑Ca & PO4 absorp from gut) supplements
• anti-resorptive therapy - bisphosphonates (alendronate, zolendronate) encourage osteoclast apoptosis but causes adynamic bone (↑fractures as ↓ bone remodelling) & can be used for 5 year periods only
• prodeposition therapy - Selective estrogen receptor modulator SERM (raloxifene) mimics progesterone action on osteoblasts ↑ activity. Slight ↑risk of thrombosis
• Recombinant PTH (Teriparatide) once daily injection ↑ serum Ca stimulates osteoblast activity more than clasts
• Strontium Ranelate - ↑bone formation ↓resorption

Question 28

what is osteomalacia/rickets (children)?

Answer 28

impaired mineralisation ( low calcium hydroyapatite) of normal osteoid tissue. ↑ osteoids to counter low mech strength - 2ry cause of osteoporosis

Question 29

what causes osteomalacia?

Answer 29

• vit D deficiency - ↓vit D causes ↓Ca absorp in GIT ↓ reabsorp in kidneys
• abnormal vit D deficiency - cant convert D2/3 to DGCCF due to renal/liver disease or drugs
• hypophosphatemia - PO4 req for hydroyapatite. low conc. causes ↑ bone resorption
• mineralisation inhibitors - biphosphonates, Al, F
• congentital causes in rickets - hypophosphatemic (↓renal PO4 reabsorption), 1alpha hydroxylase deficiency in osteoblasts (↓mineralisation), vit D resistance

Question 30

what are the signs and symptoms of osteomalacia?

Answer 30

• bone pain and deformity esp in long bones & pelvis
• fractures
• myopathy and weakness
• growth retardation in rickets

Question 31

what investigations can be carried out for osteomalacia and what are the treatments?

Answer 31

• urine - ↓Ca2+ & ↑PO4
• Bloods - ↓Ca2+ & PO4, ↑Alkaline phosphotase (osteoclast activity), ↓vit D, ↑ serum PTH
• X-rays - looser’s zones - pseudofractures
• treat underlying cause & vit D supplements - oral D2/3 require good renal function

Question 32

what is pagets disease?

Answer 32

disorder of bone remodeling as ↑osteoclast resorption followed by ↑ bone formation leading to disorganised woven bone (weaker, larger, more vascular, compresses nerves). Signs/symptoms - deep constant boring pain worse on weight bearing and path fractures & deformities (frontal bossing), sciatica, cauda equina

Question 33

what investigations and management for pagets?

Answer 33

• bloods - ↑alkaline phosphotase (osteoclast activity)
• x-ray -lessions & cortical thickening
• bone scan - incr. uptake
• bisphosphonates encourage osteoclast apoptosis