Orthopedic X-rays are necessary when a fracture, abnormality, or other clinical symptoms are indicated. They’re also essential in diagnosing degenerative conditions.
Interpreting orthopedic X-rays involves several steps, starting with the patient’s history and symptoms. Then, the X-rays are examined for X-ray alignment, bone alignment and density, cartilage characteristics, and soft tissues.
Following all of these steps is critical for accurate diagnostics. Read on to learn more.
How To Interpret Orthopedic X-Rays
A general way to remember how to interpret orthopedic radiographs is to remember your ABCs, where A stands for adequacy and alignment, B stands for bones, including outline, position, and density, and C stands for cartilage. Following is a more detailed discussion of these steps.
History
First, read the patient’s medical history for important clues to aid in imaging procedures and diagnostics. Always check the patient’s name and birthdate on the history to see if they match those on the X-rays, ensuring you have the right records.
Physical Examination
A physical examination is done before X-rays are taken. It’s important to ask the patient if there was an injury, where the point of maximal pain or tenderness is located, and whether it is acute or chronic. The doctor should also provide a differential diagnosis (i.e., infection, inflammation).
Understanding the symptoms, especially the central ray or point of maximal pain/tenderness, is critical before taking the X-ray because the radiologist will use that information to improve the quality of the X-rays.
X-ray Alignment
Now, it's time to examine the orthopedic digital X-ray images.
- First, confirm that the X-rays are of adequate quality and that you have enough views according to the following:
- Long bones: frontal and lateral views
- Joints: 3 views
- Hips: 2 views
- Hand, wrist, or foot: frontal, oblique, and lateral views
- Ankle: frontal, lateral, and mortise views
- Knee: frontal, lateral, and sunrise view for suspected patella fractures, and oblique views for tibial plateau fractures or injury of the femoral condyles
- Lumbar Spine: frontal and lateral, and sometimes a coned down view for suspected injuries at the lumbosacral junction
- Other more specific injuries or abnormalities may require additional views
- Next, interpret the anatomic alignment of the bones on the X-ray vs the other side. Be sure you know the natural degree of variation in a normal result (e.g., 5-10 degrees of valgus in the knees is normal).
- It’s usually best to examine the lateral view first since it often shows things that are not present or are more subtle in the frontal view
- Describe the proximal and then the distal bones. Distal is always described in relation to the proximal to ensure consistent interpretation
- At the level of the joint, also describe the distal relative to the proximal
- Normal X-rays will have a normal alignment, while fractures and dislocations may affect the X-ray alignment.
Bones Outline
- Identify the bone
- Look for abnormalities or discontinuities that indicate fractures and describe them
- Transverse fractures go straight across the bone
- Oblique fractures are at an angle
- Spiral fractures are a corkscrew-shaped fracture around the bone
- Comminuted fractures are when the bone has shattered into multiple pieces
- Avulsion fractures are the tearing of fragments away from the main body of the bone
- Where fractures are incomplete, look for:
- Bowing fractures where there is bending without a visible break
- Fissures are incomplete cortical breaks without bending
- Torus (buckle) fracture where the bone bends with a compression fracture and outward bulging of the cortex
- Greenstick (buckle) fractures are the bending of a bone on one side with a crack on the opposite side
- Also, describe the fracture deformity:
- Displacement may be dorsal (posterior), volar (anterior), or lateral with respect to the proximal fragment
- Shortening is where there is an overlapping of fractured ends
- Angulation is the angle created between the distal and proximal fragments
- Rotation of the bone along its long axis
Bone Density
- Look for any changes in bone shadow consistency on the X-ray, as this could indicate changes in density resulting from bone diseases, rheumatoid arthritis, etc.
- Describe any abnormal increases or decreases in density
Cartilage
Next, the cartilage is studied by examining the joint spaces seen on the radiographs.
- Look for fluid in the joints
- Widening of joint spaces could indicate a ligamentous injury or fracture
- Narrowing of joint spaces indicates arthritis
- Examine the Q angle to measure femorotibial alignment. The Q angle is formed by a line drawn from the ASIS to the central patella and another line from the central patella to the tibial tubercle. A normal Q angle is 14 degrees for males and 17 for females.
Soft Tissues
Examine the soft tissues for swelling, air in the soft tissues, and joint effusions. These may indicate trauma, tumors, infections, or occult fractures where there are clinical signs of fracture but no X-ray evidence.
Consult With Specialists
When dealing with unusual circumstances or specific issues in which you lack expertise, share the X-rays with specialists or colleagues who may be able to shed additional light on your diagnoses.
Consider if a CT Scan Or Other Tests Are Needed
If results are inconclusive, consider if a CT scan or other tests should be done. Consult with the doctor or orthopedic surgeon to decide if these are necessary.
Frequently Asked Questions
How To Read an X-Ray in Orthopedics?
Reading orthopedic X-rays involves a series of critical steps, including examining the X-ray alignment and the bones in relation to that alignment, the bone alignment in relation to other bones, the bone density, the characteristics of the cartilage, and the soft tissues.
Final Thoughts
Orthopedic X-rays are critical for diagnosing and treating injuries and degenerative conditions in bones and joints. Using quality orthopedic X-ray equipment, understanding how to use that equipment, and the steps taken to interpret those results are all essential to the process.
The radiologist should examine the X-ray alignment, bone outline, density, cartilage, and soft tissues. If there’s any uncertainty, specialists should be consulted, and extra imaging techniques may be needed.
