injuries to bones and joint upper limb Flashcards
1
Q
Describe the stages of fracture healing
A
- Remember : 1) Haematoma 2) Granulation tissue 3) Callus 4) woven bone 5) lamellar bone 6) remodelling
- Haematoma: Bone breaks, tearing blood vessels in periosteum, osteons and medullary cavity. Blood clots forming fracture haemotoma
- Disruption of blood flow to bone leads to death of bone cells around the fracture -> necrosis initiates inflammatory reaction –> phagocytes remove dead bone.
- Granulation tissue: invasion of haemotoma by capillaries and fibroblasts, induce cell proliferation.
- Callus formation: Within 48 hours chondrocytes from endosteum create internal callus which secretes fibrocartilaginous matrix between ends of broken bone.
- Periosteal chondrocytes and osteoblasts create external callus of hyaline cartilage and bone outside the break which stabilises fracture.
- Woven bone stage: osteogenic cells activate and differentiate into osteoblasts. –> lay down immature woven bone
- Woven bone becomes lamellar bone. Cartilage in callus replaced by trabecular bone by endochondral ossification.
- trabecular bone replaced by compact bone on the outer margins of the fracture.
- remodelling based on stresses placed on the bone -> excessive callus reabsorbed, medullary cavity reestablished (sign of full healing).
2
Q
What two factors does bone repair require?
A
- stability of the fracture (fracture must be immobilised in some way either plaster on the outside or internal screws).
- vascularity/ bood supply
3
Q
What are the two key joints of the clavicle?
what stabilises them?
What can fracture the clavicle?
A
- Sternoclavicular joint between sternal end of clavicle and manubrium of sternum/ 1st costal cartilage. Stabilised by sternoclavicular ligaments.
-
Acromioclavicular joint between lateral end of clavicle and the acromion of the scapula. Stabilised by several ligaments:
- acromioclavicular ligament from acromion to lateral calvicle
- conoid and trapezoid ligaments which form the coracoclavicular ligament.
- Keep the shoulder at a set distance from the manubrium
- Clavicle fracture most often caused by direct blow to the shoulder or fall on outstretched arm
4
Q
Describe the sternoclavicular joint
what can happen pathologically?
A
- sternoclavicular joint formed between sternal end of clavicle, manubrium of the sternum and 1st costal cartilage.
- surfaces covered in fibrocartilage, articular disc between sternum and clavicle.
- covered in joint capsule, with outer fibrous later and inner synovial membrane
- reinforced by sternoclavicular ligaments anterior and posterior
- also interclavicular ligament between sternal ends of each clavicle reinforcing joint capsule superiorly
- costoclavicular ligament bind 1st rib and costocartilage inferior and clavicle superiorly.
-
Dislocation of sternoclavicular joint:
- rare requires significant force
- anterior dislocations -> most common, happen when blow to shoulder rotates shoulder backwards
- posterior dislocations -> force driving shoulder forwards or direct impact
- Can compress the venous drainage
5
Q
Describe the acromioclavicular joint
what ligaments support
what is it covered in?
what movement does it allow
What is the clinical relevance?
A
- Between the acromion of the scapular and the clavicle –> reinforced by the acromiclavicular ligament and coracoclavicular ligaments (trapezoid and conoid)
- Covered in joint capsule with fibrous layer, inner synovial membrane and articular disc.
- Acromioclavicular joint allows axial rotation and anteroposterior movement
-
Clinical: Acromioclavicular joint dislocation:
- occurs when the two articulating surfaces are dislocated
- often from direct blow to joint or FOOSH
- ligamental rupture of acromioclavicular or coracoclavicular ligaments means weight of upper limb unsupported –> shoulder moves inferiorly and clavicle superiorly
6
Q
Clavicle fractures:
types and how common
presentation
treatment
complications
A
- Remember: Conoid and trapezoid ligaments support the clavicle preventing superior dislocation
- medial fractures rare (5%), lateral clavicle fractures rare (10%), middle clavicle fracture (80-85%).
- lateral clavicle fractures can tear the coracoclavicular ligaments
- middle clavicle fractures –> sternocleidomastoid muscle pulls medial fragment superior and pectoralis muscle pulls weight of arm and distal fragment inferiorly. –> Deformity and tenting of skin
- in Xray –> shortening, displacement, comminution
- Complications:
- Brachial plexus injury
- subclavian artery and subclavian vein is around 1cm from clavicle
- Treatment:
- most without surgery, conservative treatment with sling or figure of 8 strap
- Surgical if complicated comminuted or Z type fracture
7
Q
Scapular fractures:
Where can they occur?
A
- Scapular body/ blade
- Scapular spine -> often by direct blow
- glenoid -> intraarticular fracture
- acromion –> fracture through the spinous process that connects acromion to scapular spine
- coracoid process
- Scapula fracture from high energy, blunt force trauma
8
Q
Shoulder dislocations:
A
- Glenoid fossa is shallow and therefore less stable
- joint capsule is slack and relaxed underneath to allow abduction of the arm.
- Dislocations:
- anterior dislocations most prevalent (85%) -> often excess extension and lateral rotation of humerus, humeral head forced anterior and inferior into weakest part of joint capsule.
- posterior (4%) unusual and difficult to spot
- inferior (1%)
- superior displacement prevented by the coracoacromial arch
- Complications: Axillary nerve runs close proximity to shoulder joint and around surgical neck of humerus, can be damaged on dislocation or attempted reduction
- Injury to axillary -> loss sensation regimental badge region and paralysis of deltoid
9
Q
Fracture of the greater tubercle of humerus:
cause
complication
A
- Greater tubercle can be avulsed by rotator cuff action
- once reduced, the humerus will be held in place by muscle action
- Complications of avulsion fracture:
- axillary nerve can be damaged by force of the dislocation
- lose sensory innervation over regimental badge region
- loss of ability to abduct the arm
- important to test neurovascular structures before restoring a dislocation as litigation can be defended with notes
- can cause iatrogenic axillary nerve injury when attempting to reduce the fracture.
10
Q
What is axillary vein thrombosis?
What are the causes?
How does it present?
A
- Axillary vein thrombosis (saturday night palsy) = acute swelling and pain in the upper limb due to occlusion of the axillary vein or subclavian veins by a thrombus.
- presents with: oedema, cyanosis of hand, dilated collateral veins, fullness in supraclavicular fossa, jugular vein distention.
- causes: vein compression by clavicle/ 1st rib/ surrounding muscle. Seen in young, competitive athletes, patient falling asleep with arm over chair.
- Treatment -> thrombolytics via catheter into vein.
11
Q
Proximal humeral fractures:
Sites of fracture?
Nerve at risk?
A
- Sites: 1) greater tuberosity 2) humeral head 3) anatomical neck (represents the old epiphyseal plate) 4) surgical neck (most likely)
- Axillary nerve is adherent to the periosteum of the surgical neck and is at risk of damage
- as is the posterior humeral circumflex arteries
- damage to axillary nerve -> affect function of teres minor and deltoid.
- Loss of abduction of arm above 20 degrees, wea flexion, extension and rotation of shoulder.
- Loss of sensation over regimental badge region.
12
Q
Rotator cuff lesion:
Which muscle most commonly involved?
what is the anatomy?
how would a patient present?
what imaging used?
management?
A
- Supraspinatus muscle most commonly involved of rotator cuffs
- Its tendon passes under the coracoacromial arch to insert onto the greater tuberosity. Bursa that protects the tendon, but it can become impinged underneath the arch.
- Leads to supraspinatus tendonitis, (inflammation in the tendon)
- Inflammation in the tendon leads to degeneration of the subacromial bursa and supraspinatus tendon, can lead to rupture.
- Unable to initate abduction, increased pain on passive abduction above 45 degrees.
- Imaging with Ultrasound -> shows darker region of blood and no tendon , MRI best method to see tendon rupture.
-
Management:
- surgical repair for patients with good functional status, arthroscopic surgery.
- Non surgical for older/ more sedentary patients. Ice, stretching, NSAID and steroid injection.
13
Q
Humeral shaft fracture
Structures at risk
Presentation of patient
management
A
- Midshaft fracture of humerus risks Radial nerve which runs in the spiral groove and the profunda brachii artery
- Radial nerve innervates posterior arm and forearm, extensors of the wrist. Extensors will be paralysed resulting in unopposed flexion and wrist drop.
- Sensory loss over dorsal/ posterior surface of the hand, and proximal ends of lateral 3 and a half digits dorsally.
- Numbness in 1st dorsal webspace between thumb and the forefinger.
- Management: splint and functional bracing or open reduction and internal fixation with plating/ intramedullary nailing.
14
Q
Supracondylar fracture humerus:
Mechanism
structures that can be damaged
How this may present
A
- supracondylar fractures are the most common traumatic fractures seen in children
- often from FOOSH
- Can damage:
- median nerve -> anterior interosseous nerve branch to flexors and pronators in forearm are paralysed. (Not flexor carpi ulnaris / medial half flexor digitorum profundus). Wrist flexion weak.
- Flexion of thumb also prevented, thenar eminence wasting.
- Lateral 2 lumbricals affected, patient unable to flex at MCP or extend IP joints of index and middle fingers -> hand of benediction on making a fist.
- Unable to make A-Ok sign (cant flex IP joint of thumb and index finger).
- Brachial artery which divides into radial and ulnar arteries across anterior humerus can be torn
15
Q
Compartment syndrome:
What are the 5 p’s of compartment syndrome?
Treatment of compartment syndrome
A
- Pain -> that is disproportionate to the injury, worsening despite treatment.
- Pallor
- Perishingly cold
- Paralysis
- Pulselessness
- Treatment –> emergency open fasciotomy, skin incision left open for 24-48 hrs. Also limb neutral level, improve O2 w high flow O2, remove constricting dressing, treat pain with opiod.
16
Q
What is volkmann’s ischameic contracture?
how does it present?
causes?
muscles affected?
A
- deformity of the hand/ fingers/ wrist due to trauma that leads to defecit in blood supply to the forearm. Leads to damage of the forearm muscles and nerves by hypoxia.
- Presentation:
- wrist in palmar flexion
- clawed fingers
- pallor of skin
- pulselessness
- paralysis
- paraesthesia
- Causes volkmann contracture:
- Supracondylar fracture –> defecit in brachial artery supply -> often affects flexors of the wrist
- Compartment syndrome that is not recognised/ treated quickly enough
- Crush injury and bleeding disorder
- Most often affects flexor digitorum (S and P), flexor pollicis and pronator teres.
- As muscles die, the muscle shrinks and fingers get drawn into claw.
18
Q
Ulnar nerve damage :
mechanism of injury
motor defecits
sensory defecits
A
Mechanism of injury -> trauma at medial epicondyle (e.g. medial epicondyle fracture/ supracondylar fracture), compression in cubital tunnel.
Motor defecits: abduction and adduction of fingers due to interossei paralysis, adduction of thumb and positive froments sign. Movement 4th/ 5th lumbricals affected –> ulnar claw
Sensory –> loss sensation over medial 1 1/2 digits
24
Q
Bennet fracture
A
Bennet fracture = fracture of base of 1st MCP which extends into the carpometacarpal joint
Most common fracture of the thumb, often see subluxation
25
Q
mallet finger
what is it?
cause?
treatment?
A
- deformity of the finger caused when the there is damage to the extensor hood
- pain and swelling over end of finger
- end of finger lies in bent position
- inability to hold finger straight at end of the joint
- Treatment via splint that holds finger straight
