Mirel's classification to predict possible pathological fracture if boney metastasis

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Mirels classification is a system used to predict the highest risk of pathological fracture among long bones affected by metastases

  • based on site, location, matrix and/or presence of pain

Classification

  • 1 point
    • upper limb
    • involving <1/3 of bone diameter
    • blastic/sclerotic lesion
    • mild pain
  • 2 points
    • lower limb
    • involving 1/3-2/3 of bone diameter
    • mixed sclerotic/lytic lesion
    • moderate pain
  • 3 points
    • trochanteric region
    • involves >2/3 of bone diameter
    • lytic lesion
    • functional pain

This will give a minimum score of four and a maximum score of 12

  • a score of >=9 suggests that prophylactic fixation should be performed (1,2)
  • for score 8 lesions
    • treatment is based on clinical judgement and for lower scores clinical management and radiotherapy is suggested

 The overall sensitivity of the Mirel classification predicting fracture is approximately 90%

  • however specificity is only 35%
    • this means that there will be unnecessary fixations) leading to debate about its usefulness (1,3)

Reference:

  • Jawad MU, Scully SP. In brief: classifications in brief: Mirels' classification: metastatic disease in long bones and impending pathologic fracture. Clin. Orthop. Relat. Res. 2010;468 (10): 2825-7
  • Rockwood CA, Bucholz RW, M.D. CC et-al. Rockwood and Green's Fractures in Adults. Lippincott Williams & Wilkins. (2010) ISBN:1605476773
  • Piccioli A, Spinelli MS, Maccauro G. Impending fracture: A difficult diagnosis. (2014) Injury. 45 Suppl 6: S138-41. doi:10.1016/j.injury.2014.10.038

Last edited 01/2021 and last reviewed 01/2021

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