MSK Growth Injury and Repair Flashcards
(82 cards)
1
Q
What are the parts of the long bone
A
Diaphysis - shaft Metaphysic - fare at end of shaft Epiphysis - on joint side of physis Physis Growth - plate Medullary canal
2
Q
In what part of a long bone is cortical bone found
A
Diaphysis
3
Q
In what part of a long bone is cancellous bone found
A
Metaphysis
4
Q
What does cortical bone resist
A
Bending and torsion
5
Q
What does cancellous bone resist
A
Compression
6
Q
How is cortical bone laid down
A
Circumferentially
7
Q
What is cancellous bone the site of
A
Longitudinal bone growth (physis)
8
Q
Is cortical or cancellous bone more biologically active
A
Cancellous bone is very biologically active
9
Q
What are the stages or repair of a fracture
A
Inflammation
Soft callus formation
Hard callus formation
Bone remodelling
10
Q
What happens in the inflammation stage of fracture healing
A
Haematoma and fibrin clot form
Angiogenesis
Cells Accumulate
Platelet Concentrate
11
Q
What factors are needed for angiogenesis
A
Low oxygen gradient
Macrophages to produce angiogenic factors under hypoxic conditions
12
Q
What iatrogenic factors can affect the inflammation stage of fracture healing
A
NSAIDs
Open #, Surgery - loss haematoma
Poor blood supply - extensive tissue damage
13
Q
What cells accumulate in the inflammation stage of fracture repair
A
- Platelets
- PNMs
- Neutrophils
- Monocytes
- Macrophages
- Fibroblasts
- Mesenchymal and osteoprogenitor cells
14
Q
What molecules are found in the platelet concentrates of inflammation in fracture healing
A
Platelet-derived growth factor (PDGF)
Transforming growth-factor-beta (TGF-B)
Insulin like growth factor (IGF)
Vascular endothelial growth factor (VEGF)
15
Q
When does stage 2 of fracture healing begin
A
When pain and swelling subside until bony fragments are united by cartilage or fibrous tissue
16
Q
How can the 2nd stage of fracture healing by affected
A
Replace cartilage with demineralised bone matrix
Bone graft
Autogenous cancellous bone graft
Allograft bone
17
Q
What happens in the 3rd stage of fracture healing
A
Conversion of cartilage too woven bone
Increasing rigidity
18
Q
What happens in the 4th stage of fracture healing
A
Conversion of woven bone to lamellar bone
Medullary canal is reconstituted
Bone responds to loading characteristics Wolff’s law
19
Q
What is strain in relation to fractures
A
Expresses the degree of instability
- if strain is too low, mechanical induction of tissue differentiation fails
- If strain is too high, healing process does not progress to bone formation
20
Q
Causes of delayed union
A
High energy injury Instability Infection Steroids Immune suppressants Smoking Warfarin NSAID Ciprofloxacin
21
Q
What is delayed union
A
Failure to heal in expected time
22
Q
What is non-union
A
Failure of fracture healing
23
Q
Signs of non-union
A
Failure of calcification fibrocartilage Instability due to excessive osteoclasts Abundant callus formation Pain + tenderness Persistent fracture line Sclerosis
24
Q
Alternative management for delayed healing
A
Different fixation
Dynamisation
Bone grafting
25
What is the structure of ligaments made up of
```
Collagen fibres (type 1)
Fibroblasts (communicate)
Sensory fibres - proprioception, stretch, sensory
Vessels (at surface)
Crimping (allow stretch)
```
26
How are ligaments different to tendons
Ligaments have:
- lower percentage of collagen
- high percentage of proteoglycans and water
- less organised collagen fibres
- rounder fibroblasts
27
What do you need to assess in ligament rupture
Complete vs incomplete
Stability of joint?
Proprioception loss?
28
What happens in ligament rupture healing
Haemorrhage
Proliferative phase
Remodelling
29
What happens in the haemorrhage stage of ligament healing
Blood clot forms
Resorbed
Replaced with a heavy cellular infiltrate
Hypertrophic vascular response
30
What happens in the proliferative phase of ligament healing
Production of scar tissue
| Disorganised collagenous connective tissue
31
What happens in the remodelling phase of ligament healing
Matrix becomes more ligament like
| Major differences in composition, architecture and function persist
32
Treatment of ligament rupture
Conservative - if partial, no instability or poor candidate for surgery
Operative - if unstable, expectation (sportsmen), or compulsory (multiple)
33
What fibres are found in the tendinous insertion into bone
Sharpey's fibres
34
How are the cells and fibres of tendons arranged
Longitudinallarrangement of tenocytes and type I collagen
| Fascicles of long narrow spiralling collagen bundles
35
What are the collagen bundles in tendons covered by
Endotendon
36
What are the fascicles in tendons covered by
Epitendon
37
What are tendons covered by
Epitenon
38
Where can the blood supply for tendons by found
In the paratenon
39
How are tendons connected to their tendon sheath
By a vincula
40
What happens in achilles tendon degeneration
Intrasubstance mucoid degeneration
May be swollen, painful, tender
Precursor to rupture
41
What happens in de Quervain's stenosing tenovaginitis
Tendons of EPB and APL passing through common tendon sheath at radial aspect of wrist become inflamed
Causes swelling, tenderness, heat, redness
Positive Finklestein's test
42
What is enthesiopathy
Inflammation at insertion to bone - can occur in a:
- muscle / tendon (usually at muscle origin rather than tendon insertion) - tennis elbow
- ligament - i.e. plantar fasciitis
43
What is traction apophysitis
i. e. Osgood Schlatter's Disease
- inflammation in the insertion of patellar tendon into anterior tibial tuberosity
- occurs in adolescent active boys due to recurrent load
44
What is an avulsion fracture
An injury to the bone in a location where a tendon or ligament attaches to the bone
When an avulsion fracture occurs, the tendon / ligament pulls off a piece of the bone
45
Treatment of avulsion
Conservative
- limited application
- retraction tendon
Operative
- reattachment of tendon through bone
- fixation of bone fragment
46
What are the mechanism of an achilles tendon intrasubstance rupture
50% - Pushing off with weight bearing forefoot whilst extending the knee joint - i.e. sprint starts of jumping movements
15% - unexpected dorsiflexion of ankle (i.e. slipping into hole)
10% - violent dorsiflexion of plantar flexed foot i.e. fall from height
47
Signs of achilles tendon rupture
Positive simmonds test
| Palpable tender gap
48
What is an example of a musculocutaneous junction tear
Medial head of gastrocnemius at musculotendinous junction with achilles tendon
49
Treatment of tendon rupture
```
Mobilise
Splint
Physio
Steroid injection
Operative - if high risk re-rupture, high activity, ends cannot be opposed
```
50
A alpha fibre
- size in microns
- speed (m/sec)
- function
- 15 microns
- 60-100 m/sec
- Large motor axons, muscle stretch and tension sensory axons
51
A beta fibres
- size in microns
- speed (m/sec)
- function
- 12-14 microns
- 30-60 m/sec
- touch, pressure, vibration and joint position sensory axons
52
A gamma fibres
- size in microns
- speed (m/sec)
- function
- 8-10 microns
- 15-30 m/sec
- gamma efferent motor axons
53
A delta fibres
- size in microns
- speed (m/sec)
- function
- 6-8 microns
- 10-15 m/sec
- sharp pain, very light touch and temperature sensation
54
B fibres
- size in microns
- speed (m/sec)
- function
- 2-5 microns
- 3-10 m/sec
- sympathetic preganglionic motor axons
55
C fibres
- size in microns
- speed (m/sec)
- function
- <1 microns
- <1.5 m/sec
- dull, aching, burning pain and temperature sensation
56
Common nerve compression syndromes
Carpal tunnel syndrome - median nerve at wrist
Sciatica - spinal root by IV disc
Mortons' neuroma - digital nerve in 2nd or 3rd webspace of forefoot
57
What are axons of peripheral nerves covered in
Endoneurium
58
What are nerve fascicles covered with
Perineurium
59
What is a peripheral nerve covered with
Epineurium
60
What is the classification of nerve trauma
Sunderland
- Grade 1 - neurapraxia
- Grade 2 - axonotmesis
- Grade 3 - neurotmesis
- Grade 4 - neurotmesis +
- Grade 5 - neurotmesis ++
61
What is neurapraxia
Nerve is stretched or bruised but in continuity (endometrium intact)
Causes reversible conduction block (local ischaemia and demyelination)
Prognosis good - weeks-months
62
What is axonotmesis
Endoneurium intact but axons disrupted either by stretching, crushing or direct blow
Wallerian degeneration follows
Prognosis fair - sensory recovery better than motor
63
What is Wallerian degeneration
An active process of degeneration occurring when a nerve fibre is cut or crushed and part of the axon distal to the injury degenerates
64
What is neurotmesis
Complete nerve division due to laceration or avulsion
No recovery unless repaired operatively
Endoneural tubes disrupted so high chance of misfiring during regeneration
Poor prognosis
65
what are closed nerve injuries associated with
Nerve injuries in continuity - neuropraxis, axonotmesis
66
What are open nerve injuries associated with
Nerve division - neurotmetic injuries, knives or glass
67
Treatment of closed nerve injuries
Spontaneous recovery possible
| Surgery after 3 months if no recovery seen clinically or by electromyography
68
Treatment of open nerve injuries
Early surgery
69
Sensory features of nerve injury
Dysaethesiae (disordered sensation)
- anaesthetic
- hypo / hyper aesthetic
- paraesthetic (pins and needles)
70
Motor features of nerve injury
```
Paresis (weakness)
Paralysis
Wasting
Dry skin
Diminished reflexes
```
71
Why does dry skin occur in nerve injury
Loss of tactile adherence as sudomotor nerve fibres not stimulating sweat glands in skin
72
What is the process of healing in a nerve injury
```
Wallerian degeneration
Degradation of myelin sheath
Proximal axonal budding - after ~4 days
Regerenation at rate of 1mm/day / 1"/month
Pain is first modality to return
```
73
What does prognosis of nerve injury depend on
Whether nerve is pure (only sensory or motor) or mixed (both sensory and motor within same nerve)
How distal the lesion is (proximal nerve)
74
What test and investigation can be done to monitor recovery of a nerve injury
Tinel's test - tap over site of injury and paraesthesia will be felt as far distally as regeneration has progressed
Electrophysiological Nerve Conduction Studies
75
When would you use direct repair for a nerve injury
Laceration
| No loss of nerve tissue
76
When would you use nerve grafting for a nerve injury
Where there is nerve loss
| Use sural nerve
77
What is the rule of 3 in relation to surgical timing in a traumatic peripheral nerve injury
Immediate surgery within 3 days for clean and sharp injuries
Early surgery within 3 weeks for blunt contusion injury
Delayed surgery, after 3 months for closed injury
78
How is tone affected in UMN and LMN lesion
UMN - increased tone
| LMN - decreased tone
79
How are deep tendon reflexes affected in UMN and LMN lesion
UMN - reflexes increased
| LMN - reflexes decreased
80
How is clonus affected in UMN and LMN lesion
UMN - clonus present
| LMN - clonus absent
81
How is babinski affected in UMN and LMN lesion
UMN - present
| LMN - absent
82
How is atrophy affected in UMN and LMN lesion
UMN - absent
| LMN - present
