1. Imaging Findings

Based on the aforementioned X-ray, bone scan, and CT images, the following key characteristics can be observed:

• On the anterior aspect of the right tibia, the X-ray shows a locally longitudinal, fine lucent line (slightly decreased radiographic density) along with mild surrounding cortical thickening.
• The bone scan reveals a significant localized increase in radiotracer uptake (“hot spot”) in the mid-portion of the right tibia, indicating heightened local metabolic activity.
• CT cross-sectional images show a slender lucent line within the tibial cortex, accompanied by surrounding sclerosis, consistent with the radiographic features of a longitudinal stress fracture.

2. Possible Diagnoses

Taking into consideration the patient’s recurrent right anterior tibial pain that is activity-related, along with the imaging findings and clinical context, the following possible diagnoses are suggested:

• Stress Fracture: Occurs without a significant history of trauma but is caused by prolonged, repetitive, and high-load exercise or stress, leading to microinjury that outpaces the repair process in the tibia. Localized pain typically worsens after activity and improves with rest. Classic imaging findings include a linear low-density area within the cortex and increased tracer uptake.
• Tibial Periostitis: Excessive exercise or prolonged improper training can cause periostitis of the tibia, often presenting as pain along the anteromedial aspect of the tibia. However, periostitis typically does not show a distinct linear lucent sign in the bone, and on bone scans, it can appear as diffuse or band-like uptake, differing from the focal increase seen in stress fractures.
• Fibular Tendon or Soft Tissue Lesion: While soft tissue lesions are more common, they typically do not exhibit pronounced cortical disruption or local bone abnormalities on bone scans or CT, making this possibility less likely.

3. Final Diagnosis

Taking into account the patient’s age (46 years), clinical symptoms (anterior tibial pain for several weeks, exacerbated by activity and relieved by rest), and imaging findings (the longitudinal lucent line and localized abnormal tracer uptake on X-ray, CT, and bone scan), the most likely diagnosis is:

Longitudinal stress fracture of the anterior aspect of the right tibia.

Further examinations, such as MRI, may identify local bone marrow edema and a linear low signal in the cortical bone, providing additional support for this diagnosis. However, based on the available imaging and clinical information, stress fracture is strongly indicated.

4. Treatment Plan and Rehabilitation Program

For a stress fracture, the following management and rehabilitation strategies are generally adopted:

• Conservative Management:
  • Reduce or temporarily discontinue aggravating activities, such as running or jumping, to allow sufficient rest and healing for the bone tissues.
  • Consider using braces or protective supports to help reduce stress on the tibia.
  • Oral nonsteroidal anti-inflammatory drugs (NSAIDs) can alleviate pain and inflammation, but caution must be taken regarding potential adverse effects from long-term high-dose use.
• Surgical Treatment:
  • Conservative management is generally sufficient for most stress fractures. However, if the fracture line progresses significantly or fails to heal over an extended period (particularly in anterior tibial stress fractures prone to nonunion), surgical intervention—such as intramedullary nailing or internal fixation—may be considered.
• Rehabilitation and Exercise Prescription:
  • It is recommended to follow the FITT-VP principle (Frequency, Intensity, Time, Type, Progression, and Volume):
    1. Early Recovery Phase: Engage only in low-intensity, low-impact or non-weight-bearing exercises (e.g., swimming, stationary cycling) to maintain cardiovascular fitness.
    2. Intermediate Transition Phase: Once pain has subsided and the fracture shows initial healing, gradually introduce resistance and weight-bearing exercises (such as lower limb strength training) 2–3 times per week. Start at light to moderate intensity for 20–30 minutes per session.
    3. Late Strengthening Phase: Following adequate fracture healing confirmed by imaging and clinical assessments, progressively resume running and related activities 2–3 times per week, incorporating intervals of slow jogging and walking. Carefully monitor for pain, and adjust training volume if pain worsens.
  • Continuously monitor local pain and swelling. If pain recurs or swelling increases significantly, promptly decrease or discontinue training and consult a physician.
• Nutritional Support:
  • Ensure sufficient intake of protein, calcium, vitamin D, and other micronutrients to promote fracture healing and muscle recovery.

Disclaimer: This report provides a reference analysis based on the provided information and does not replace an in-person consultation or professional medical advice. If you have any concerns or your symptoms worsen, please seek prompt medical care or consult an orthopedic specialist.