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Mirels' Criteria for Prophylactic Fixation

Scores impending pathologic fracture risk in a long-bone metastasis to guide prophylactic fixation.

Mirels' Criteria for Prophylactic Fixation
Site of lesion
Pain
Radiographic lesion type
Size (relative to bone diameter/cortex involved)
Result4 points

Low fracture risk (~4%); prophylactic fixation generally not indicated.

Mirels' score
4

When to use

  • Deciding whether a metastatic long-bone lesion warrants prophylactic surgical stabilization before pathologic fracture occurs.

Formula

Sum of 4 domains (site, pain, lesion type, size), each scored 1-3. Total range 4-12; ≥9 favors prophylactic fixation.

Pearls and pitfalls

  • A score of 8 is considered borderline and requires clinical judgment; radiation oncology and orthopedic oncology input is valuable.
  • Validated primarily in long bones; upper-limb-specific cutoffs may differ from lower-limb lesions.

References

  1. Mirels H. Clin Orthop Relat Res. 1989;(249):256-264.