From the Guidelines
The best clinical examination specialty to diagnose a stress fracture is Radiology, as it utilizes imaging modalities such as radiography, MRI, and bone scan to confirm the diagnosis. When suspecting a stress fracture, a comprehensive evaluation including palpation for focal tenderness and assessment of risk factors should be performed. The hop test, which involves having the patient stand on the suspected injured limb and hop several times, can be a useful clinical exam special test to find a stress fracture, particularly in lower extremity stress fractures, especially in the tibia, metatarsals, and femoral neck 1. However, the test has good sensitivity but limited specificity, so positive findings should be confirmed with imaging studies. According to the American College of Radiology, radiography is the imaging modality of choice for baseline diagnosis, and MRI has greatly improved our ability to diagnose radiographically occult stress fractures 1.
Some key points to consider when diagnosing stress fractures include:
- The patient's history of new or repetitive athletic activity, which can increase the risk of fatigue fractures in patients with normal bone 1
- The location of the suspected stress fracture, as certain athletic activities often result in specific sites of fatigue fracture 1
- The use of imaging modalities such as radiography, MRI, and bone scan to confirm the diagnosis, as they have different sensitivities and specificities for detecting stress fractures 1
- The importance of prompt therapeutic measures, as incomplete stress fractures have the potential of progressing to completion and requiring more invasive treatment or delay in return to activity 1
It's also important to note that a negative hop test or negative imaging study does not completely rule out a stress fracture, particularly in early or non-weight bearing bone injuries. Therefore, a comprehensive evaluation and follow-up imaging studies may be necessary to confirm the diagnosis. As stated in the most recent study 1, the next imaging study after negative or indeterminate radiographs should be chosen based on the specific location and type of suspected stress fracture.
From the Research
Diagnostic Approaches for Stress Fractures
The diagnosis of stress fractures involves various clinical examination specialties, including:
- Conventional x-ray images as the standard initial method 2, 3, 4
- Magnetic Resonance Imaging (MRI) for its high sensitivity and ability to provide further information, such as evidence for a pathological fracture 2, 3, 4
- Computed Tomography (CT) for an exact representation of the fracture line and preoperative planning 2, 4
- Bone scintigraphy as a nuclear medicine procedure to detect increased bone metabolism in the area of a fracture 2, 3, 5, 6
Imaging Findings
Imaging findings for stress fractures include:
- X-ray signs: gray cortex sign, periosteal reaction, and a fracture line often oriented perpendicular to the cortex with a parallel sclerotic line 2
- MRI findings: periosteal and medullary edema, reaction in the surrounding soft tissue, and a T1-hypointense fracture line 2, 4
- CT findings: a hypodense fracture line often associated with an adjacent sclerotic area 2, 4
Diagnostic Algorithms
For a correct diagnosis, it is essential to be familiar with the appropriate imaging modalities and their respective findings 2. If initial x-rays are normal and symptoms persist, an MRI should be performed to rule out other causes, such as a pathological fracture 2, 3, 4. In some cases, bone scintigraphy may be used as an alternative or additional diagnostic tool 3, 5, 6.