Medial tibial stress syndrome

Medial tibial stress syndrome (MTSS), also known as shin splints, describes a spectrum of stress injury that occurs at the medial tibia. This term is often used to indicate any type of tibial stress injury or the earlier manifestations of a tibial stress lesion before a fracture component can be identified 1. It is considered a low risk stress fracture.

Typically occurs in athletes (e.g. runners/jumpers) and is characterized by localized pain that occurs during exercise at the medial surface of the distal two-thirds of the tibial shaft.

A "one-leg hop test" is a functional test, that can be used to distinguish between MTSS and a stress fracture: a patient with MTSS can hop at least 10 times on the affected leg where a patient with a stress fracture cannot hop without severe pain 2.

CT is not particularly sensitive (~40%) 3. It may reveal mild osteopenia as an early sign of fatigue damage of cortical bone in tibial diaphysis 3,4.

May show focal hyperechoic elevation of the periosteum with irregularity over the distal tibia and increased flow on Doppler interrogation. 

MRI is the most sensitive radiological examination (~88%) 3. It may demonstrate a spectrum of findings ranging from normal to periosteal fluid to marrow edema to actual stress fracture 5. The medial cortex (+/- posterior cortex) is most commonly affected 3

These findings are graded using the modified Fredericson classification system which allows grading of the MRI findings with a good correlation with clinical severity and outcome. It allows an estimate to a safe return to activity in athletes. It is as follows 7,8:

  • grade 1: periosteal edema only
  • grade 2: bone marrow edema appreciated only on T2-weighted sequences
  • grade 3: bone marrow edema appreciated on both T1 and T2-weighted sequences
  • grade 4
    • 4a: multiple discrete areas of intracortical signal changes
    • 4b: linear area(s) of intracortical signal change correlating with a frank stress fracture

Bone scintigraphy is relatively sensitive (~75%) 3 and may demonstrate high uptake in the affected region, characteristically along the posterior tibial aspect on lateral views.

  • tibial stress fracture: there can be some overlap depending on the definition.
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Article information

rID: 10776
Section: Syndromes
Synonyms or Alternate Spellings:
  • Shin splints
  • Shin splint syndrome
  • MTSS
  • Medial tibial stress syndrome (MTSS)
  • Shin splint

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Cases and figures

  • Figure 1: illustration - Fredericson classification
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  • Case 1
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  • Case 2: MTSS grade 3
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  • Case 3
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  • Case 4
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  • Case 5
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  • Case 6: ultrasound
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  • Case 7
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  • Case 8: ultrasound
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  • Case 9
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  • Case 10
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