Orthopaedics - general principles Flashcards
What is an open fracture?
Open fracture: a direct communication between the fracture site & the external environment
Most often through skin but also pelvic fracture may be internally open, having penetrated in to the vagina/rectum
What is the difference of an ‘in-to-out’ and ‘out-to-in’ injury?
‘in-to-out’ = sharp bone ends penetrate the skin from beneath
‘out-to-in’ = a high energy injury penetrates the skin, traumatising the subtending soft tissues and bone
List the most common fractures that can become open
Tibial
Phalangeal
Forearm
Ankle
Metacarpal
Describe the different outcomes of an open fracture
1) Skin: very small wound to significant tissue loss
2) Soft tissues: range from very little tissue devitalisation to significant muscle/tendon/ligament loss requiring reconstructive surgery
3) Neurovascular injury
4) Infection
Describe the clinical features of an open fracture
Pain, swelling and deformity with an overlying wound or punctum
Examination – check neurovascular status & overlying skin for any skin or tissue loss
What is the classification of open fractures?
Gustilo-Anderson classification can be used to classify open fractures:
-type 1: <1cm wound and clean
-type 2: 1-10cm wound and clean
-type 3A: >10cm wound and high-energy, but with adequate soft tissue coverage
-type 3B: >10cm wound and high-energy, but with inadequate soft tissue coverage
-type 3C: all injuries with vascular injury
3A = ortho alone, 3B = requires plastic input, 3C = vascular input
Which investigations will patients with a suspected open fracture have?
Basic blood tests – including a clotting screen and a group & save
Plain film radiograph
CT-scan for very comminuted/complex fracture patterns
Describe the management of open fractures
Suitable resus and stabilisation
Urgent realignment and splinting of the limb
Broad-spectrum antibiotic cover, a tetanus vaccination is required
Photograph the wound & remove any gross debris
Definitive surgical management – requires debridement of the wound & fracture site
Ensure the wound is washed out with copious volumes of saline & definitive skeletal stabilisation within 72 hours
Define compartment syndrome
Compartment syndrome is defined as a critical pressure increase within a confined compartmental space
Most common sites affected are in the leg, thigh, forearm, foot, hand and buttock
Describe the pathophysiology of compartment syndrome
Fascial compartments cannot be distended & any fluid that is deposited there will cause an increase in the intra-compartmental pressure
Increase in pressure, the veins will be compressed -> increases the hydrostatic pressure within them and causes fluid to move out of the veins in the compartment
Next, the traversing nerves are compressed – causes a sensory +/- motor deficit in the distal distribution (paraesthesia is common)
Leg becomes ischaemic when the intra-compartmental pressure reaches the diastolic blood pressure
Describe the clinical features of compartment syndrome
Severe pain, disproportionate to the injury, which is not readily improved with initial measures
-pain made worse by passively stretching the muscle bellies traversing the affected fascial compartment
Paraesthesia (presence of evolving neurology)
Affected compartment may feel tense but not generally swollen
If disease progresses, the features of acute limb ischaemia will subsequently develop (5 P’s)
List investigations for compartment syndrome
A clinical diagnosis, based on symptoms and risk factors present
Most reliable diagnostic test – an intra-compartmental pressure monitor
CK may aid diagnosis
Describe the management of compartment syndrome
Immediate surgical treatment via urgent fasciotomies
Prior to definitive intervention, additional management steps should include:
-keep the limb at a neutral level with the patient
-improve oxygen delivery with high flow oxygen
-augment BP with bolus of intravenous crystalloid fluids
-remove all dressings/splints/casts down to the skin
-treat symptomatically with opioid analgesia
Once fasciotomies have been performed – skin incisions are left open & re-look is planned for 24-48 hours where assess for any dead tissue that needs to be debrided
Monitor renal function – potential effects of rhabdomyolysis/reperfusion injury
OA pathophysiology
Degradation of cartilage and remodelling of bone due to an active response of chondrocytes in the articular cartilage & inflammatory cells in the surrounding tissues
Release of enzymes from these cells -> break down collagen & proteoglycans, destroying the articular cartilage
Exposure of underlying subchondral bone results in sclerosis -> reactive remodelling changes that lead to the formation of osteophytes & subchondral bone cysts
Joint space is progressively lost over time
OA risk factors
Obesity
Advancing age
Female gender
Manual labour occupations
OA clinical features
Most common joints – small joints of hands & feet, hip joint, knee joint
Symptoms are insidious, chronic and gradually worsening
Pain and stiffness in joints, worsened with activity, relieved by rest
Prolonged OA results in deformity & reduced range of movement
Examination – inspect for deformity, crepitus
OA investigations
Plain radiographs
- L: loss of joint space
- O: osteophytes
- S: subchondral cysts
- S: subchondral sclerosis
OA management
Conservative – education, weight loss, local heat/ice packs, PT
Medical – simple analgesics & topical NSAIDs, intra-articular steroid injections
Surgical – arthroplasty, other options: osteotomy & arthrodesis
Acutely swollen joint investigations
Routine bloods – FBC, CRP, ESR, serum urate
Plain film radiographs of affected joint
Joint aspiration – can be sent for WCC, microscopy, culture & sensitivity, light microscopy (for crystals)
Gout
Inflammatory arthritis caused by the collection of monosodium urate crystals in a joint
Caused by hyperuricaemia leading to crystallisation of the urate in the joint space
Classically affects the 1st MTPJ
Often episodic, diagnosis is made by joint aspiration and microscopy
Acute gout – NSAIDs, prophylactic agents – allopurinol for prevention
Pseudogout
Inflammatory arthritis caused by deposits of calcium pyrophosphate crystals within the joint
More likely to affect proximal joints – elbow and knee
Present with acute onset joint swelling
Risk factors: advanced age, hyperparathyroidism and hypophosphatemia
Diagnosis made via joint aspiration and microscopy and treated acutely with NSAIDs
Spondyloarthropathies
Group of conditions comprising of psoriatic arthritis, ankylosing spondylitis, reactive arthritis & enteropathic arthropathy
Classified as being seronegative conditions and are associated with HLA-B27
All can present with ‘axial arthritis’ or affecting any joint in the body as oligoarthritis/monoarthritis, also can cause enthesitis and dactylitis
Most diagnoses are made clinically
Haemarthrosis
Bleeding into a joint cavity, most common cause is a joint injury
Initial investigations – routine bloods, plain film radiographs, joint aspiration can be performed (can make a definitive diagnosis)
Initial management – RICE and sufficient analgesia, majority of cases are managed conservatively, including the correction of any underlying coagulopathies
Metastatic bone cancer
Most common cause of bone cancer, most common primary sites are renal, thyroid, lung, prostate and breast
Most common site for a bony metastases is the spine
Rarely treated surgically, with mainstay of disease management via systemic therapies and is palliative
Prophylactic nailing of certain long bones can be performed in certain individuals at high risk of pathological fractures
Bone cancer risk factors
Genetic association
Previous exposure to radiation/alkylating agents in chemotherapy
Benign bone conditions eg. Paget’s disease and fibrous dysplasia
Bone cancer clinical features
Pain – not associated with movement and is worse at night
Mass may be palpable & fracture without a history of trauma (pathological fracture)
Benign bone tumours
Osteoid osteoma
Osteochondromas
Chondroma
Giant cell tumour
Malignant bone tumours
Osteosarcoma
Ewing’s sarcoma
Chondrosarcoma
Osteoid osteoma
Arise from osteoblasts, often around the second decade of life, more common in males
Typically small tumours located usually around the metaphysis of long bones
Present with localised progressive pain, worse at night, made better with NSAIDs
Radiologically show a small mass, comprised of a radiolucent nidus with a rim of reactive bone
Most can be managed conservatively, severe pain = may warrant surgical resection
Osteochondroma
Benign bony tumours forming as an outgrowth from the metaphysis of long bones covered with a cartilaginous cap
Develop in the second decade of life and more common in males
Most are detected incidentally
Most can be managed conservatively (serial radiological imaging every 4-6 months), however those with significant deformity/neurological symptoms = surgical resection
Chondroma
Arise from chondroblasts within the medullary cavity of the bones/from the cortical surface
Present in patients 20-50 years old, most commonly affecting the long bones
Most are asymptomatic, but can present as a pathological fracture
Plain film radiograph -> well circumscribed oval lucency with intact cortex
Most can be observed but if large/symptomatic = require removal with curettage and bone grafting
Giant cell tumour
Arise from multinucleated giant cells and stromal cells
Occur in patients 20-30 years old, usually affecting the epiphysis of long bones
Patients will typically present with pain, swelling or joint movement limitation
Plain radiograph – eccentric lytic area, giving a ‘soap bubble’ appearance
Surgical resection is treatment of choice
Osteosarcoma
Most common malignant primary bone tumour
Bimodal age of onset – 10-14 years or in those aged > 65 years, most commonly found at the metaphysis of the distal femur or proximal tibia
Localised constant pain and tender soft tissue mass may be palpable
Tissue biopsy is needed for diagnosis
Aggressive resection with systemic chemotherapy
Ewing’s sarcoma
Paediatric malignancies, more common in males & arise from primitive poorly differentiated neuroectodermal cells, commonly affect the diaphysis of long bones
Present with a painful and enlarging mass with tenderness and warmth
Plain film radiographs – lytic lesion with periosteal reactions (‘onion skin’)
Management – neoadjuvant chemotherapy following by surgical excision
Chondrosarcoma
Malignant tumours of the cartilage, age of onset is 40-60 years, typically affecting the axial skeleton
Typically present with a painful and enlarging mass, plain film radiographs demonstrate lytic lesions with calcification, cortical remodelling & endosteal scalloping
Low grade lesions – intralesional curettage
Intermediate and high grade lesions – wide en-bloc local excision
Bone tumours investigations
Vary depending on suspected tumour type
Most will obtain initial plain film radiographs
MRI imaging & CT imaging can be useful in determining cortical involvement
Bone biopsy may be required for a definitive diagnosis
Radiological features of bone tumours
Benign lesions – sharp and well-defined, lacking soft tissue involvement and no cortical destruction
Malignant lesions – often poorly defined with rough borders, involving soft tissues and have cortical destruction
Osteomyelitis
Infection of the bone
Most cases are acute and bacterial in origin
Common causative organisms – staph aureus, streptococci, H. influenza, P. aeruginosa
Osteomyelitis pathophysiology
Bacteria enter the bone tissue -> express adhesins to bind to the host tissue proteins & produce an extracellular matrix -> pathogens are able to propagate, spread and seed further
Chronic causes -> devascularisation of the affected bone, subsequent necrosis & resorption of the surrounding bone (‘floating’ piece of dead bone = sequestrum – not penetrated by abx as avascular)
Involucrum can form, whereby the region becomes encased in a thick sheath of periosteal new bone
Osteomyelitis risk factors
Diabetes mellitus
Immunosuppression
Alcohol excess
IV drug use
Osteomyelitis clinical features
Severe pain in the affected region & associated low grade pyrexia
Constant pain & can be worse at night
Examination – tender, overlying swelling and erythema, patient may be unable to weight bear if lower limb
Potts disease
Infection of the vertebral body and the intervertebral disc by M. TB
Patients will present with back pain +/- neurological features, low grade fever
MRI is gold-standard investigation
Most cases will require a prolonged course of anti-TB medication, however surgical intervention may be required for abscess drainage
Osteomyelitis investigations
Routine blood tests, blood cultures
Plain film radiographs
Definitive diagnosis can be achieved through MRI but gold standard diagnosis is from culture from bone biopsy at debridement
Osteomyelitis management
Patient is clinically well -> patients will require long-term IV abx therapy
Patient clinically deteriorates -> surgical management may be required to prevent chronic osteomyelitis developing: curettage of the area
Osteomyelitis complications
Overwhelming sepsis
Mortality
Growth disturbances
Recurrence of infection
Chronic osteomyelitis
Chronic osteomyelitis
Present with localised ongoing bone pain and non-specific infection symptoms
Surgical management involves local bone and soft tissue debridement for definitive source control, alongside extensive long-term abx therapy
Likely need complex staged reconstruction with prolonged rehab, if not, amputation can be considered
Septic arthritis
Infection of a joint
Main causative organisms – staph aureus (adults), gonorrhoea (most common in sexually active patients) and salmonella (especially in those with sickle cell disease)
Septic arthritis risk factors
Increasing age
Pre-existing joint disease
Diabetes mellitus
Immunosuppression
CKD
Hip/knee joint prosthesis
IV drug use
Septic arthritis clinical features
Single swollen joint causing severe pain
Pyrexia
Examination – joint is red, swollen and warm, pain on active and passive movements
Unable to weight bear
Septic arthritis investigations
Routine bloods, blood cultures
Joint aspiration should be performed before abx are given
Imaging – plain radiograph, USS can be useful to guide joint aspiration and for drainage, CT/MRI can be useful in specific joint infections
Septic arthritis management
Empirical abx treatment
Infective native joints require surgical irrigation and debridement in theatre to aid in source control
If in prosthetic joint -> revision surgery is typically needed
Septic arthritis complications
Osteoarthritis
Osteomyelitis
