A 60-year-old woman underwent bone scintigraphy, MRI and CT for evaluation of pain in her left lower leg.
A 60-year-old woman presented with a history of significant pain in her left lower leg for several months, which was exacerbated by walking. There was no antecedent history of trauma, and the patient had no significant medical or surgical history. Physical examination revealed diffuse tenderness over the anterior aspect of the left lower leg. Laboratory data were within normal limits. No abnormality was identified on radiography of her left tibia and fibula. A radionuclide bone scan was performed which showed a linear area of abnormal increased tracer uptake in the anteromedial aspect of the distal half of the left tibia (figure 1). An MRI was subsequently acquired, which showed significant oedema in the soft tissues around the distal half of the left tibia, and marrow oedema within the adjacent tibia. Following the administration of intravenous gadolinium, abnormal enhancement was demonstrated in the soft tissues around the tibial diaphysis and within the marrow (figure 2). CT showed a vertically oriented, linear lucency in the anteromedial tibial cortex, with some adjacent periostitis and endosteal new bone formation (figure 3), and the diagnosis of a longitudinal stress fracture was made. With several weeks of rest, her symptoms improved significantly.
The majority of stress fractures are transversely or obliquely oriented [1]. Longitudinal stress fractures are relatively rare, and occur mainly in the tibia, but have also been reported in the fibula, patella and femur [2]. The mechanism of longitudinal stress fracture formation is unclear; it has been postulated that it may occur secondary to longitudinal extension of an oblique fracture, due to rotational stresses, or due to some cortical weakness at the site of the nutrient foramen [2]. These fractures may occur as a consequence of strenuous activity in young athletes (stress fractures) or due to normal mechanical strain in weakened bones, for example in osteoporotic patients (insufficiency fractures). In the latter group of patients, there may be no history of increased activity nor of trauma [2]. The symptoms in either case are often relieved by rest [3]. Longitudinal stress fractures are rarely visualised on radiographs, therefore these patients often present a diagnostic challenge [1]. In addition, the fact that this entity is rare means that the diagnosis is often not considered [4]. Bone scintigraphy shows abnormal isotope uptake in the affected area; the longitudinal pattern of uptake, in combination with the patient’s history and physical examination, may be diagnostic. MRI typically shows an area of bone marrow oedema with further oedema, or haematoma, in the soft tissues around the fracture site. A linear low-signal fracture line is visible on T1-weighted MRI in up to 73% of cases [1]. In cases where the fracture line is not visible, the MRI findings are non-specific as tumour or infection may have similar appearances. Another rare entity which may have a similar clinical presentation and similar appearances on bone scintigraphy and MRI, when no fracture line is identified, is transient tibial oedema [5]. CT has a higher sensitivity and specificity for detection of longitudinal tibial stress fractures and usually shows the fracture line, often with some associated callus, as in this case [1]. The correct diagnosis of this condition is important, as the differential for the appearances on bone scintigraphy and MRI includes both infection and neoplasia, however longitudinal stress fractures are benign and self-limiting processes, which are successfully treated with rest [2].
Longitudinal Stress Fracture of the Tibia.
• This patient is a 60-year-old female complaining of left lower leg pain.
• Bone scintigraphy (bone scan): Indicates a longitudinal area of increased radiotracer uptake in the proximal to mid portion of the left tibial shaft, suggesting local hypermetabolism of bone.
• Magnetic Resonance Imaging (MRI): On T1-weighted images, a longitudinal low-signal line is visible in the proximal mid-tibia (in some sequences, a linear high or low signal corresponding to the fracture line may be seen). Surrounding bone marrow and soft tissue show edema or minor hemorrhage. No obvious soft tissue mass is noted.
• Computed Tomography (CT): A longitudinal fissure-like hypodense line is observed in the left tibia, surrounded by a small amount of newly formed callus, confirming the presence of a fracture line. No significant bone destruction, periosteal reaction, or erosive changes are evident.
Considering the patient’s age (60 years old, possibly with osteoporosis), clinical symptoms (left lower leg pain), and radiological findings (longitudinal radioactive uptake on bone scan, longitudinal low-signal fissure on MRI, CT evidence of fracture line and callus), the most likely diagnosis is a tibial longitudinal stress fracture (insufficiency fracture).
• Conservative Treatment: Primarily focused on reducing weight-bearing on the affected limb and ensuring adequate rest to decrease local mechanical stress.
• Medications: If osteoporosis is present, supplements such as calcium, vitamin D, or anti-osteoporotic medications (e.g., bisphosphonates) may be considered under medical guidance. Protein supplementation may also be recommended as needed.
• Surgical Indications: For stable stress fractures without displacement, or with only minimal displacement, surgery is generally not required. If nonunion or severe displacement occurs, internal fixation may be considered.
Given the likelihood of osteoporosis and a stress fracture, rehabilitation should be carried out progressively and individually, with an emphasis on safety and bone protection:
Throughout the rehabilitation process, regular follow-up is recommended to assess fracture healing and recovery progress, allowing timely adjustments to the exercise plan and avoiding premature or excessive weight-bearing that may lead to re-injury.
This report is for reference only and does not replace in-person consultations or professional medical advice. If you have any concerns or if your condition changes, please seek medical attention promptly and follow professional guidance.
Longitudinal Stress Fracture of the Tibia.
