Medications, imaging, and fractures
Imaging
There are several types of medical imaging used to assess different tissues and structures in the body. Below are the main types.
X-ray (radiography)
- Best for: Bones, fractures, joint alignment, lung conditions
- How it works: Uses ionizing radiation to create images of dense structures
- Common uses:
- Fractures & dislocations
- Arthritis
- Lung infections (e.g., pneumonia)
- Foreign objects
- Limitations: limited soft tissue visibility, radiation exposure
- Interpreting an X-ray
- High-density tissue (e.g., bone) - absorbs x-rays to a greater degree, and appears white on the film.
- Low-density tissue (e.g., the lungs) - absorbs X-rays to a lesser degree, and appears black on the film
- Intermediate density tissue (e.g., muscle and fat) - appears as shades of grey on the x-ray film
Computed tomography (CT scan)
- Best for: Bones, soft tissues, internal bleeding, internal organs, and the brain.
- How it works: Combines multiple X-rays to create cross-sectional images
- Common uses:
- Bone fractures and complex injuries
- Internal bleeding (trauma)
- Stroke
- Tumors
- Lung and abdominal conditions
- Limitations: higher radiation exposure than X-rays
- Interpreting CT scan
- Dense structures (like bone and calcifications) appear lighter (white).
- Lucent structures (like air and fat) appear darker (black).
Magnetic resonance imaging (MRI)
- Best for: Soft tissues, brain, muscles, ligaments, and nerves
- How it works: Uses strong magnets and radio waves to generate detailed images
- Common uses:
- Ligament and tendon injuries
- Brain and spinal cord conditions
- Tumors
- Disc herniations
- Limitations: expensive, time-consuming, may be contraindicated with certain ferromagnetic metal implants and devices (e.g., some pacemakers, aneurysm clips) - safety depends on the specific implant
- Interpreting MRI
- T1 MRI highlights anatomy, provides crisp images, and shows fluids as dark
- T2 MRI focuses on pathology, making fluids bright, which is ideal for visualizing inflammation, edema
Ultrasound
- Best for: Soft tissues, pregnancy, blood flow
- How it works: Uses high-frequency sound waves to create real-time images.
- Common uses:
- Pregnancy monitoring
- Soft tissue injuries (e.g., muscle tears)
- Blood clots (Doppler ultrasound)
- Organ imaging (e.g., liver, kidneys)
- Limitations: poor image quality for bones and deep structures
Nuclear medicine imaging (e.g., PET scan, bone scan)
- Best for: Organ function, cancer detection, metabolic activity
- How it works: Uses radioactive tracers to highlight metabolic activity
- Common uses:
- Cancer detection (PET scan)
- Bone metastases (bone scan)
- Stress fracture/microfracture (bone scan)
- Thyroid and kidney function
- Limitations: radiation exposure, high cost
Fluoroscopy
- Best for: Real-time imaging of movement (e.g., swallowing, joint motion)
- How it works: Continuous X-ray imaging allows real-time assessment
- Common uses:
- Barium swallow for digestive tract
- Cardiac catheterization
- Joint injections
- Limitations: higher radiation exposure than standard X-rays
Example: choosing the right imaging study
A patient reports a popping sensation and knee instability after twisting the joint during sports. The supervising PT suspects a ligament tear. Which imaging modality is best suited to visualize this soft-tissue injury?
Answer: MRI - it provides the soft-tissue detail needed to visualize ligaments, tendons, and cartilage. X-ray is best for bone, and CT is best for bone and internal bleeding, so neither shows a ligament tear as clearly.
Lab values and bone density testing
Besides imaging, the chart may include lab work and bone density results relevant to musculoskeletal conditions:
- DEXA scan (bone density): a T-score of or lower indicates osteoporosis; a T-score below but above indicates osteopenia.
- ESR and CRP: elevated levels suggest inflammation or infection.
- Rheumatoid factor and anti-CCP: elevated levels support a diagnosis of rheumatoid arthritis.
- Uric acid: elevated levels are associated with gout.
- Alkaline phosphatase, calcium, and vitamin D: reflect bone metabolism and healing.
Medications
Medications for musculoskeletal conditions target pain, inflammation, and muscle spasm or spasticity; the main classes are NSAIDs, opioids, corticosteroids, and antispasticity/muscle-relaxant agents.
- Non-steroidal anti-inflammatory drugs (NSAIDs)
- Mechanism of action: inhibit cyclooxygenase (COX) enzymes, which reduces prostaglandin production and decreases inflammation, pain, and fever
- Key adverse effects to monitor: GI ulcers, indigestion, and increased bleeding risk
- Opioids
- Mechanism of action: bind to opioid receptors in the central nervous system, altering the perception of pain
- Key adverse effects to monitor: decreased respiration rate (respiratory depression), constipation, and addiction risk with long-term use
- Corticosteroids
- Mechanism of action: suppress the immune and inflammatory response throughout the body when taken systemically (for example, by mouth), or mainly at the site when injected locally
- Key adverse effects to monitor: osteoporosis (increased fracture risk with long-term use), high blood pressure, and weight gain/diabetes
- Baclofen (antispasticity agent)
- Mechanism of action: a GABA-B receptor agonist that acts mainly at the spinal cord to suppress spinal reflexes and reduce spasticity - distinct from the centrally acting muscle relaxants below, which target acute muscle spasm rather than spasticity
- Key adverse effects to monitor: drowsiness, dizziness, fatigue, and muscle weakness; abrupt withdrawal can cause seizures, hallucinations, and rebound spasticity
- Muscle relaxants (for acute muscle spasm)
- Mechanism of action: acts on the central nervous system (CNS) to interfere with the transmission of nerve impulses to muscles, reducing muscle spasms and tension
- Key adverse effects to monitor: drowsiness, dizziness, muscle weakness, and nausea
PT implications:
- Analgesics and NSAIDs can mask pain, so the patient may push past safe limits - rely on objective signs and RPE rather than self-reported pain alone.
- When the PT’s plan allows, time sessions to coincide with the medication’s peak effect so the patient can tolerate the intervention.
- Drowsiness and dizziness from opioids, baclofen, and muscle relaxants raise fall risk - guard closely during transfers and gait.
- After a local corticosteroid injection, the tendon is temporarily weaker, so follow the PT’s plan about avoiding heavy loading in that area.
Fractures
A fracture is a partial or complete break in the bone. There are many different types of fractures. Bone fractures are often caused by falls, injury, or a direct hit or kick to the body. Overuse or repetitive motions can cause stress fractures. Bone healing moves through four stages: inflammatory → soft callus → hard callus → remodeling.
Types of fractures
- Open (compound): The bone breaks through the skin, exposing it to the environment
- Closed (simple): The bone breaks but does not penetrate the skin.
- Transverse: A straight break across the bone
- Oblique: A diagonal break at an angle to the bone
- Spiral: A twisting break that spirals around the bone
- Greenstick: A partial break that occurs in children’s flexible bones
- Comminuted: The bone breaks into multiple fragments
- Stress fracture: A small, hairline crack caused by repetitive stress
- Impacted fracture: The broken ends of the bone are driven into each other
- Avulsion fracture: A small piece of bone is pulled away by a tendon or ligament
An acute fracture typically causes intense pain with swelling, bruising, and tenderness at the injury, trouble moving the part, and sometimes a deformity such as a limb that looks out of place.
Salter-Harris fracture
A Salter-Harris fracture is a type of bone fracture that occurs in children and adolescents, involving the growth plate (physis). Salter-Harris fractures are classified into five types based on the location and extent of the fracture, using the mnemonic SALTR:
| Type | Mnemonic | Structures involved | Key point |
|---|---|---|---|
| I | S - straight across | Physis only | No bone involvement |
| II | A - above | Physis and metaphysis | Most common type |
| III | L - lower | Physis and epiphysis | Involves joint surface |
| IV | TE - through everything | Metaphysis, physis, and epiphysis | Crosses entire bone |
| V | R - rammed (crush) | Crush injury to the growth plate | Often not visible initially, worst prognosis |
Fat embolism syndrome
After a long-bone fracture, fat droplets from the marrow enter the circulation. A few patients develop fat embolism syndrome, most often after fractures of the femur, pelvis or tibia, and after intramedullary nailing or arthroplasty. Signs usually appear 24 to 72 hours after the injury:
- Respiratory: tachypnea, dyspnea and cyanosis; oxygen saturation can fall before the patient complains
- Neurological: confusion, drowsiness, seizures or coma
- Skin: a flat petechial rash on the chest, axilla, neck and conjunctiva
- Other: tachycardia and fever