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Clinical History

The patient, a female runner, presented with pain at the right lower leg, aggravating by walking.There was no previous history of direct trauma

Imaging Findings

The patient presented with pain at the right lower leg, aggravating by walking. There was no previous history of direct trauma The pain was mild but subsequently the pain worsened and occurred earlier, limiting participation in sports activities. She reported pain upon palpation or percussion of the affected area. The plain radiograph showed normal findings. The MR imaging protocol included gradient T2 weighted, Axial T1 weighted (Fig 3) and STIR in coronal plane (Fig 1). It showed oedema in the soft tissues around the diaphysis of the tibia, and a fracture line. No soft tissue mass was seen. CT examination (Fig 2) showed a horizontally oriented, linear lucency in the posterior tibial cortex, with adjacent periosteal new bone formation. CT confirmed the diagnosis of a stress fracture.

Discussion

Stress fractures are overuse injuries of bone. These fractures, which may be incomplete or complete, result from repetitive subthreshold loading that, over time, exceeds the bone's intrinsic ability to repair itself.
Range of the annual incidence of stress fractures among athletes and military recruits is 5-30%. Stress fractures, like most overuse injuries, typically are multifactorial in etiology; thus, if the diagnosis has been made or is suspected, it is important to determine the risk factors. Intrinsic risk factors are low BMD, lower limb malalignment, foot structure height, tall stature, muscle fatigue, strength imbalance, pathologic bone states, menstrual/hormonal irregularities and genetic predisposition. Extrinsic risk factors are excessive volume or intensity of training in sport disciplines – for example, runners are prone to tibial shaft stress fractures, whereas tennis players appear to be most vulnerable to navicular injuries, and volleyball players may be at a relatively increased risk of pars interarticularis injuries. Worn-out training shoes, inadequate nutrition, calcium, vitamin D medication usage - for example, chronic steroid use.
Note that no single physical examination test is sufficiently sensitive and specific to permit the unequivocal diagnosis of a stress fracture.
It is very important to exclude differential diagnosis like tumours of the bone, especially osteoid osteomas etc.
Imaging studies can help the physician confirm the suspected clinical diagnosis. Conventional radiographic findings are often unremarkable, particularly early in the continuum that leads from stress reaction to stress fracture. In some cases, conventional radiography remains negative, despite clear diagnostic evidence of fracture on bone scan or cross-sectional imaging. Other conventional radiographic findings include an area of cortical lucency that suggests a nonhealing stress fracture. Computed tomographic (CT) examination is a useful diagnostic imaging tool. A 3-phase bone scan (scintigraphy) may be indicated if conventional radiographic findings are negative or nondiagnostic and the clinical suspicion of stress fracture remains high. The bone scan is diagnostic of stress fracture if focal isotope uptake occurs in the area of clinical interest on the third phase of the scan. Scintigraphy is extremely sensitive but the drawbacks of scintigraphy include a relative lack of specificity and anatomic resolution. Because of the limitations inherent to scintigraphy, MRI may be a reasonable first-line imaging procedure. MRI provides greater anatomic detail of the area in question, and fat-suppressed (short TI inversion recovery [STIR]) and water-weighted (T2) signal sequences permit detection of marrow edema and/or periosteal reaction occurring during the earliest stages of stress fracture formation with a level of sensitivity that rivals bone scanning. Treatment consists of activity restriction to minimize symptoms before engaging in a program of increasingly demanding strengthening and conditioning exercise, leading to an eventual return to play in 8-12 weeks. Some authors recommend immobilization as initial therapy. Failure of nonoperative care warrants consideration of surgical intervention. Options include reamed intramedullary nailing and internal fixation with bone grafting. Postoperative recovery time averages 6 months. Complications of stress fracture may include avascular necrosis, nonunion, malunion, posttraumatic arthrosis, and persistent disabling pain.

Differential Diagnosis List

Tibial stress fracture in a runner

Final Diagnosis

Tibial stress fracture in a runner

Liscense

Figures

Fig 1-MR

Fig 2-CT

Fig 3 -MR

Medical Analysis Report

1. Radiological Findings

In the provided CT and MRI images, a mild localized bony change is observed in the cortical region of the right tibia, manifested as:

CT Axial View: A localized density abnormality is seen along the outer cortex of the tibia, showing band-like or small localized sclerotic or lucent areas (indicated by arrows), suggesting a local bony reaction.
MRI Sequences: On T2-weighted and STIR sequences, there is increased bone marrow edema signal near the medial cortical aspect of the tibia, accompanied by a mild subperiosteal or subcortical reaction, consistent with early stress fracture (or stress reaction) changes.

No significant large-scale soft tissue swelling or abnormal signals are noted, indicating that the primary lesion is confined to the cortical bone and surrounding bone marrow.

2. Potential Diagnoses

Combining the medical history (a 43-year-old female with long-term running training and weight-bearing lower extremity pain), clinical symptoms (pain aggravated by walking), and the localized bony abnormalities on imaging, the possible diagnoses include:

Stress Fracture
Characteristics: Common among individuals who engage in high-intensity or repetitive weight-bearing activities (e.g., running). The cortical bone and bone marrow may exhibit signs of stress reaction, shown as localized bone marrow edema or a sclerotic band.
Bone Tumor or Tumor-like Lesion (e.g., Osteoid Osteoma)
Characteristics: Can also present with localized cortical changes or a sclerotic response, but typically associated with a characteristic pattern of night pain relieved by medication and more pronounced local bone destruction or new bone formation. Should be cautiously ruled out radiologically.
Other Bone Diseases or Chronic Bone Injuries
Characteristics: Such as osteoporosis or bone infection. However, given the history and clinical presentation, these are relatively less likely.

3. Final Diagnosis

Considering the patient’s age, gender, exercise history (prolonged running, local weight-bearing pain), and radiological findings (localized cortical sclerosis or edema in the tibia), the most likely diagnosis is:

Right Tibial Stress Fracture (Tibial Stress Reaction/Incomplete Fracture)

If there is unexplained persistent pain or uncertainty regarding the imaging results, further investigations (such as high-resolution MRI of the suspicious lesion or a bone scan) may be considered to exclude other bone tumors or pathologies.

4. Treatment Plan and Rehabilitation

4.1 Treatment Strategies

Conservative Management: Initially, it is recommended to reduce or suspend high-intensity weight-bearing activities such as running. Use crutches or braces to reduce local stress and ensure adequate rest.
Medication and Nutritional Management: If there is evidence of reduced bone density, supplementation with calcium, vitamin D, or other pharmacological interventions may be considered under medical supervision.
Surgical Treatment: For cases where long-term conservative management fails, or nonunion, malunion, or severe complications occur, intramedullary nailing or bone grafting procedures might be considered. The postoperative recovery period typically spans around 6 months.

4.2 Rehabilitation and Exercise Prescription

During rehabilitation training, plans should be individualized and gradually progressed according to the FITT-VP principle (Frequency, Intensity, Time, Type, Volume, and Progression):

Acute Phase (0-4 weeks)
- Avoid or reduce running, jumping, or other high-impact weight-bearing exercises. Swimming and cycling are suitable low-impact crossover training options to maintain cardiovascular fitness.
- Use braces or support devices as recommended to relieve stress on the affected limb.
- Light core strengthening exercises and gentle training of adjacent muscle groups like the quadriceps and gastrocnemius (e.g., isometric contractions) can be performed.
Recovery Phase (4-8 weeks)
- Gradually increase weight-bearing activity time and frequency, such as light walking and lower limb resistance exercises.
- Consider physical therapy modalities like ultrasound therapy, heat packs, or massage to improve blood circulation and relax muscles.
- Monitor pain and swelling. If symptoms significantly worsen, adjust the training intensity promptly.
Strengthening Phase (8-12 weeks)
- In the absence of significant pain, gradually transition to jogging or intermittent running with controlled increases in running volume and speed.
- Continue core stabilization, balance, and lower-limb muscle strength training. Exercises such as seated or partial squats should be introduced progressively, with caution in adding load.
- Ensure proper footwear or insoles to provide adequate biomechanical support for the foot.
Return-to-Activity Phase (12 weeks and beyond)
- The focus in this phase is on sports-specific technical training, gradually resuming previous performance levels. Closely monitor any recurring pain or discomfort.
- Periodic imaging follow-up or additional assessments may be conducted to confirm complete fracture healing.

Throughout the rehabilitation process, if the patient has underlying bone fragility or other chronic conditions, close communication with healthcare professionals is essential. Training intensity and methods should be adjusted to ensure both safety and effectiveness.

Disclaimer:
This report provides a reference-based analysis derived from the available information and does not replace face-to-face consultation or professional medical advice. If you have further concerns or changes in your condition, please seek prompt medical attention and a professional evaluation.

Human Doctor Final Diagnosis

Tibial stress fracture in a runner

AI Doctor