MSK Flashcards
Following microscopic repair of a severed digital nerve, you could expect sensation of the tip of the finger to grow back:
1mm/ day
What scan is most sensitive for stress fractures
Stress fractures can be confirmed on radionucleotide bone scan several days before changes are evident on a radiograph
What is the rule of 2’s for x-rays
- 2 views
- 2 joints
- 2 occassions
- 2 sides (left and right)
what is an avulsion fracture
An avulsion fracture is an injury to the bone in a location where a tendon or ligament attaches to the bone. When an avulsion fracture occurs, the tendon or ligament pulls off a piece of the bone.
What is a pathological fracture
A pathologic fracture is a bone fracture caused by weakness of the bone structure that leads to decrease mechanical resistance to normal mechanical loads.
What is a stress fracture
A stress fracture is a small crack in a bone, or severe bruising within a bone. Most stress fractures are caused by overuse and repetitive activity, and are common in runners and athletes who participate in running sports, such as soccer and basketball.
What variables influence how well a fracture heals?
- Would immobilisation
- Vascular supply
- Presence of infection
- Physical stress
What are some common paediatric fractures
Paediatric fractures often have distinct fracture patterns due to the unique properties of growing bones.
- The periosteum in growing bones is thicker and stronger than in adult bones, which is why children are more prone to more incomplete fractures, such as the greenstick fracture or torus fracture
- In addition, the periosteum is metabolically active, this feature explains why childhood fractures heal faster than fractures in adults
Common paediatric fractures
- Distal radius fracture
- Clavicular fracture
- Supracondylar humerus fracture
What is a Salter Harris fracture and its classification
Definition: Physeal or growth plate fracture
Salter-Harris Fracture Classification
- Type I: Transverse fractures of the physis, separating the epiphysis from the metaphysis
- Type II: Transverse fractures of the metaphysis and physis. Often involves separation of a triangular section of the metaphysis
- Type III: Transverse fractures of the physis and epiphysis. May extend to the joint, affecting the articular surface
- Type IV: Fractures through the metaphysis, physis, and epiphysis, entering the joint
- Type V:Impaction and disruption of the physis, occurs due to a crush or compression injury
Treatment for Salter Harris fractures
Salter-Harris Type I and II
- Closed reduction if displaced and immobilization in a cast with re-evaluation after 7-10 days
- In case of severe dislocation or concomitant injury: surgical intervention
Salter-Harris Type III and IV
- Open reduction is required to realign the joint surface because both these types affect the joint
- Surgical intervention includes open reduction and internal fixation
Complications of Salter-Harris fracture
- Disruption of growth and bone deformity (especially Salter-Harris Types III-V)
- Leads to discrepancies in limb-length or angular deformities
- Younger patients are more likely to experience growth arrest
- Excessive limb growth is rare
Treatment for open fractures
- IV antibiotics
- Start as soon as possible, continue for 24 hours post closure
- Usually 1st generation cephalosporin e.g. cefazolin
- Tetanus
* If have not had a boost in past 5 years. Initiate in emergency room, toxoid 0.5mL or immunoglobulin - Extremity Stabilization and Dressing
- Stabilisation – splint, brace or traction for temporary stabilization
- Dressing –
- Remove gross debris from wound, do not remove any bone fragments
- Place sterile saline-soaked dressing on wound
- Operative management
- Urgent irrigation and debridement and antibiotic beads in open dirty wounds
- Soft tissue coverage is ideal (flap coverage)
- Reconstruction for bone loss
Systematic approach to X-rays
- Demographics
- Patient name, DOB, age, sex
- Previous films (Compare with previous films and compare left to right)
- Other orientations (Need AP and usually another view e.g. lateral)
- Radiograph detail
- Date
- Type (AP, lateral, other view)
- Area of the body (including left or right)
- Adequacy
- Area: ideally need joint above and below
- Rotation
- Penetration (exposure)
- Artifact
- Interpretation
- Alignment
* Joints and bones – look for dislocation or subluxation - Bones
- Cortex – trace around looking for fractures
- Bone fragments
- Texture of bone between cortex
- Cartilage
- Joint spaces
- Disruption of joint contours
- Signs of OA/ RA/ psoriatic gout/ pseudogout
- Soft tissue
- Disruption
- Swelling
- Foreign bodies or calcification
What is Osteoarthritis and the common joints it affects
“Wear and tear” - Progressive functional joint disorder, characterised by altered joint anatomy, especially loss of articular cartilage and is non-inflammatory.
Common joints
- Knee > hand > hip
X-ray findings of osteoarthritis
- Loss of joint space
- Osteophytes
- Subchondral sclerosis
- Sub-articular cysts
Causes of osteoarthritis
- Elderly
- Family history
- Pre-existing peculiarities of joint anatomy
- Obesity
- Excessive overuse (local inflammation, previous injuries)
- Trauma
What are heberden and bouchards nodes (Also what joints in the hand does osteoarthritis affect)
Heberden’s node - pain and nodular thickening on the dorsal sides of the distal interphalangeal joints
Bouchard’s nodes - pain and nodular thickening on the dorsal sides of the proximal interphalangeal joints
symptoms of osteoarthritis
- Pain on exertion, which is relieved with rest
- Pain in complete flexion and extension
- Crepitus on joint movement
- Joint stiffness and restricted range of motion
- Morning joint stiffness usually lasting < 30 minutes
- Gradual onset
- Large weight bearing joints
In contrast to osteoarthritis, RA does not affect the first metatarsophalangeal or DIP joint
Management of OA
Initial
- Non-Pharm - Weight loss, exercise, heat therapy
- Pharm - Paracetamol, Ibuprofen (NSAIDs), topical capsaicin
Then what else?
- Duloxetine
- Corticosteroid injection
- Joint replacement
Differences between RA and OA
What is RA
Rheumatoid arthritis is a chronic inflammatory autoimmune disorder that is characterised by pain, welling, stiffness and destruction of synovial joints. The joints affected are usually peripheral, symmetrical and predominantly small joints (usually hand and feet)
Clinical featues of RA (Inluding extra-articular)
- Pain, hot, swollen, restricted movement
- Long duration of stiffness in mornings > 30 minutes
- Systemic, usually small joints of hands and feet
- Often symmetrical
- Characteristic deformities: Swan neck, Boutonniere and Hitchhiker thumb deformity
Extra-articular manifestations of RA
- Rheumatoid nodules
- Pulmonary disease: Pleuritis, pleural effusion, alveolitis
- Cardiac: pericarditis, valvular heart disease, pericardial effusion
- Ocular: feratoconjunctivits sicca, episcleritis, scleritis
- Neurologic: peripheral neuropathy, nerve entrapment, myelopathy
- Vasculitis: nailfold, systemic
- Cutaneous: palmar erythema, pyoderma gangrenosum
- Haematologic: neutropaenia/ splenomegaly (Fetty’s), hyperviscosity
Investigations for RA
Lab tests
- CRP/ ESR (acute phase reactants) – elevated
Serology
- ACPA (anti-CCP) Anti-citrulinated peptide – autoimmune antibodies [high specificity]
- Rheumatoid factor – autoantibodies against the Fc region of IgG [low specificity]
- Antinuclear antibodies (ANA) – elevated in 30% of cases
Synovial fluid analysis
- Synovial fluid is collected by joint aspiration, Findings:
- Cloudy yellow appearance
- Sterile specimen with leucocytosis
Imaging
- X-ray
- Early – soft tissue swelling, demineralization
- Late – joint space narrowing, erosions of cartilage and bone, demineralisation
Treatment of RA
Non-Pharm
- refer to rheumatologist
- smoking cessation
- weight loss and exrcise
Pharm
Acute anti-inflam therapy
- Glucocorticoids e.g. methylprednisalone acetate 120mg IM
- NSAIDs
DMARDs
- Methotrexate 10mg orally, once weekly
- Leflunomide 10-20mg orally OD
- Sulfasalazine
- Hydroxychloroquine
bDMARDs
- TNF-a inhib (Adalimumab 40 mg OD)
- Ankinra (Anti-IL6)
How do you monitor progress of RA treatment
Inflammation is most reliably assessed by the number of swollen or tender joints as well as the inflammatory markers C-reactive protein (CRP) and/or erythrocyte sedimentation rate (ESR); neither measure should be used alone. Patient-reported outcomes include pain, physical function, psychological health, sleep patterns, relationships, and participation in social and work-related activities.
What is osteoporosis and osteopenia
Osteoporosis is a complex skeletal disease characterised by low bone density and micro-architectural defects in bone tissue, resulting in increased bone fragility and susceptibility to fracture.
Osteopenia – decreased bone strength but less severe than osteoporosis
Causes of Osteoporosis (Primary and Secondary)
Primary Osteoporosis
- Type I – post-menopausal women
- Oestrogen stimulates osteoblasts and inhibits osteoclasts the decreased oestrogen levels following menopause leads to increased bone resorption.
- Type II – gradual loss of bone mass (age > 70)
Secondary Osteoporosis
- Drug induced – especially long term corticosteroids
- Endocrine – hyperthyroidism, hypogonadism, hyperparathyroidismrenal disease
- Immobilization
- Alcohol abuse
Complications of osteoporosis
Pathological fractures – spontaneous fracture following mild physical exertion or minor trauma
- Localisations – vertebral > femoral neck > distal radius (colles)
- Vertebral compression fractures are commonly asymptomatic but may cause acute back pain
- Decreased height (2-3cm with each fracture)
- Thoracic hyperhyphosis
Investigations for osteoporosis
DXA (Dual-energy X-ray absorptiometry)
- Calculates bone mineral density
- Osteoporosis: T-score <= - 2.5
- Osteopenia: T-score of -1 to -2.5
Radiography
- Can be diagnosed if vertebral compression fractures
Other tests
- Urine – increase cross-links (e.g. deoxypyridinoline), markers of bone turnover
- Blood tests
- serum calcium,
- serum 25-hydroxyvitamin D concentration
- Alkaline phosphates
- Serum phosphates
- Serum TSH concentration
- Liver biochemistry and kidney function
treatment of osteoporosis
Pharmacological
- Sufficient calcium and vitamin D intake
1. Bisphosphonates (Alendronate, Risedronate) - Decrease bone resorption (osteoclastic activity)
1. Denosumab – RANK Ligand Inhibitor - Decrease bone resorption (osteoclastic activity). Monoclonal antibody blocks RANKL-RANK interaction
1. Teripartide - Recombinant PTH – increases bone formation – osteoblastic activity
- Side effects - Increase risk of DVT
-
Raloxifene
* Selective oestrogen receptor modulator – decrease bone resorption (osteoclastic activity) -
Testosterone
* Decrease bone resorption
Non- Pharmacological
- Stop smoking/ drinking
- Exercise
- Falls reduction strategies
What is gout?
Gout is a common inflammatory arthropathy characterised by painful and swollen joint resulting from precipitating uric acid crystals.
Acute gout attacks typically manifest with a severely painful big toe (podagral) and occur most often in men following triggers such as alcohol consumption.
Causes of gout
Hyperuricaemia predisposes to gout.
- Uric acid is an end-product of purine metabolism that is removed feom the human body by renal excretion
- Insufficient excretion or increased production of purines leads to hyperuricaemia, possible triggering a gout attack
- Primary hyeruricaemia (aggravated by poor dietary habits)
- Secondary hyperuricaemia
- Decreased uric acid excretion Medications (NSAIDs, loop diuretics, thiazides, pyrazinamide)
- Chronic renal insufficiency
- Ketoacidosis, lactic acidosis
- Increased uric acid production
- High cell turnover (haemolytic anaemia, psoriasis, chemotherapy, radiation)
- Enzyme defects
- High-protein diet
- Obesity
- Combined decrease excretion and overproduction
- Alcohol consumption
clinical features of gout
- Usually mono-arthritic during first attack
- Very painful joint with redness, decreased range of motion, swelling and warmth
- More likely to occur at night, typically waking the patient
- Symptoms peak after 12-24 hours; regression may take days to weeks
- Most commonly metatarsophalangeal inflammation of the big toe
Chronic gout
- Tophi formation – multiple painless hard nodules with possible joint deformities, usually on extensor surface
- Renal manifestations with uric acid nephrolithiasis and uric acid nephropathy
- Progressive joint destruction
Investigations for gout
- Arthrocentesis
- Polarized light microscopy findings – negatively birefringent monosodium urate crystals
- Synovial fluid findings: WBC > 2000/uL with > 50% neutrophils
- Laboratory tests
- Increased serum uric acid levels
- Typical in acute attacks – raised WBC and ESR
- Imaging
- Normal in early disease
- MRI – detect tophi formation
- CT – bone erosion and tophi
- X-ray – in acute gout isn’t useful, in chronic gout detects punched-out lytic bone lesions
Treatment in acute and chronic gout
*Do not start urate-lowering until 2-4 weeks after attack resolved
Treat as it is super painful and high uric acid levels is risk factor for CVD, stroke and kidney disease
Acute gout
- NSAIDs
- Glucocorticoids (prednisolone 15-30mg orally)
- Intra-articular corticosteroids
- Colchicine 1mg orally initially, then 500mcg 1 hour later, as a single one-day course (total 1.5mg)
- Bind tubulin which stops microtubule assembly to affect cell division, neutrophil motility, decrease chemokine production, overall it stops inflammatory cell recruitment
- Side effects – vomiting, diarrhoea
Chronic gout
- Allopurinol 50mg orally, daily for 4 weeks; then increase by 50mg every 2 to 4 weeks or by 100mg every 4 weeks to achieve the target serum uric acid concentration
- Inhibits Xanthine oxidase to decrease uric acid synthesis
- Side effects – GI, stevens-Johnson syndrome
- Allopurinol increases the effects of mercaptopurine and azathipprine
-
Febuxostat
* Non-purine selective inhibitor of XO -
Uricase agent – Rasburicase
* Catalyses conversion of uric acid to allantoin -
Uricosuric agent – Probenicid 250mg BD and titrated up, Benzbromarone
* Blocks urate reuptake in the proximal tubules, acting on URAT 1
*Add on prophylactic colchicine to prevent flare up with urate lowering therapy
What is Pseudogout (Calcium Pyrophosphate Deposition Disease) and what are the clinical features, investigations and treatment
Clinical features
- Usually monoarthritis, mostly affecting the knees and other large joints
- May become chronic (osteoarthritis with CPPD most common symptomatic CPPD)
- Progressive joint degeneration with episodes of acute inflammatory arthritis
Investigations
- Arthrocentesis
- Polarized light microscopy findings – rhomboid-shaped, positively birefringent CPPD crystals
- Synovial fluid findings: WBC between 10,000-50,000/uL with > 90% neutrophils
- Laboratory tests
- Hypercalcaemia
- Serum uric acid levels are normal
- Typical in acute attacks – raised WBC and ESR
- Imaging (X-ray)
- Cartilage calcification of the affected joint
- Fibrocartilage and hyaline cartilage may be affected
Treatment
- Asymptomatic cases do not require treatment unless there is an underlying condition (hyperparathyroidism)
- NSAIDs
- Colchicine or intra-articular corticosteroids
- Arthroscopic lavage
- Joint replacement
pathophysiology and pathogens in osteomyelitis
- Haematogenous osteomyelitis
- Most commonly due to a single pathogen
- Bodily infection à enters bloodstream à infiltrates bone marrow
-
Exogenous osteomyelitis
* Usually multiple pathogens - Post-traumatic – infection following deep injury
- Contiguous – spread of infection from adjacent tissue (e.g. secondary to infected foot ulcer)
Pathogens
- most common –> Staphylococcus aureus
- staph epidermidis (Diabetic0
- Pseudomonas aeruginnosa (IVDU)
Clinical feature of osteomyelitis
Acute
- Pain at site of infection, possibly related to movement
- Point tenderness, swelling, redness, warmth
- Malaise, fever, chills
Chronic
- Recurrent pain
- Swelling, redness
- Local sinus tract formation, perhaps draining pus
Investigations in osteomyelitis
Lab tests
- Inflammatory markers (raised CRP and ESR)
- Leukocytosis
- Blood cultures
Imaging
- X-ray – in later stages can see bone destruction, sequestrum formation, periosteal reactions
- MRI – shows signs of inflammation < 5 days after infection onset
- Skeletal scintigraphy – visualises areas of increased bone turnover
- Sonography – assess soft tissue involvement
- Radionuclide-labelled leukocyte scintigraphy
Biopsy – confirmatory test
Treatment for osteomyelitis
- Bed rest and immobilization of affected extremity
- Antibiotics
- IV vancomycin + cefeprime/ ciprofloxacin
1. Surgical - Debridement of necrotic bone or tissue
- Abscess drainage
- Infected prosthetic removal
- Revascularisation in case of poor wound healing due to peripheral artery disease
Common pathogens and variants of septic arthritis
Pathogens
- Staphylococcus aureus
- Streptococci
- Staphylococcus epidermidis
- H. influenzae
- Neisseria gonorrhoea
Variants
- Prosthetic joint infection
- Bacterial coxitis
- Gonococcal arthritis
- Lyme disease arthritis
Clinical features of septic arthritis
- Acute onset
- Usually monoarticular (knee, hip, wrist, shoulder)
- Triad of:
- Fever
- Joint pain
- Restricted range of motion
- Join may be swollen, red, warm
Investigations for septic arthritis
- U/S guided arthrocentesis (definitive diagnosis requires detection of bacteria in synovial fluid)
- Synovial fluid gram stain and culture
- Increased synovial fluid WBC (above 50,000 per high-powered field) and dominance of polymorphonuclear (neutrophil > 90% à bacterial) cells
- Fluid appears yellowish-green and turbid
- Also alleviates pain by decreasing intraarticular pressure
- Lab tests
- Raised CRP/ ESR
- Blood culture – at least 2 sets of blood cultures to rule out a bacteraemic origin
- Imaging
- Look for signs of underlying osteomyelitis and concurrent joint disease
- U/S – effusion, oedema of the surrounding soft tissue, possible empyema
- X-ray – unremarkable early; osteolysis usually visible after 2-3 weeks
- MRI or scintigraphy
Treatment for septic arthritis
- Following arthrocentesis and culture, simultaneous empiric antibiotic therapy (based on gram stain) and evacuation of purulent material
- Gram positive cocci à Vancomycin
- Gram negative cocci à ceftriaxone
- Grame negative bacilli à ceftriaxone
- Pseudomonas infection à Gentamicin
- Tailor antibiotics to gram stain and culture
1. Immobilisation and NSAIDs for pain relied and reduce inflammation
Physiotherapy to prevent contracture of both joint and capsule
Clinical features (exam findings) of a lipoma
- Slow-growing round, soft ‘rubbery’ tumour
- Non-tender
- Localization: almost any subcutaneous region
- Mobile, superficial, soft, <5cm
What is bursitis and where are some common locations
Bursitis is an cute or chronic inflammatory condition of a bursa. A bursa is a jelly-like space that usually contains a small amount of synovial fluid. A bursa lies between a tendon and either bone or skin to act as a friction buffer and facilitate movement of adjacent structures. In primary care, bursitis is most commonly present in the knee, subacromial, trochanteric, retro calcaneal and olecranon bursae.
- Olecranon bursitis – inflammation of the bursa of the elbow joint that is often caused by leaning on the elbow for long periods of time
- Subacromial bursitis – inflammation of the bursa located between the acromion and the supraspinatus muscle that is often caused by repetitive overhead motion
- Prepatellar bursitis – inflammation of the bursa between the skin and the patella that is often caused by chronic strain on flexed knee joints or after falls on the knee