Validation of a proposed radiographic bone defect classification system


      • A skeletal defects classification scheme is an important step towards standardising the assessment of these complex injuries.
      • Interobserver reliability testing demonstrated the proposed classification system had substantial agreement between observers.
      • Intraobserver variability showed a range of substantial to almost perfect agreement of each observer following a three-week interval.
      • The classification scheme is based primarily on conventional orthogonal radiographs, requiring no sophisticated technology or elaborate calculations.
      • The distinction between the various elements of the classification scheme are consistent with the prior orthopaedic trauma literature.



      To clinically validate a recently proposed classification scheme of post-traumatic bone defects.

      Methods and materials

      Open fractures were classified utilising a newly introduced classification system. This classification system is based on plain radiographs, assessing the extent and local geometry of bone loss, including: D1 - Incomplete Defects; D2 - Minor/Sub-Critical (Complete) Defects (<2 cm); and D3 - Segmental/Critical Sized Defects ( 2 cm). Reliability was assessed among six independent assessors (three trauma orthopaedic surgeons and three orthopaedic training surgeons) using Fleiss’ kappa tests. 43 open fractures from a tertiary referral trauma centre and their radiographic series were analysed.


      Interobserver reliability testing demonstrated the proposed classification system had substantial agreement between the 6 observers, κ = 0.623 (z = 33.8), p < 0.001. Intraobserver variability showed a range of substantial to almost perfect agreement of each observer following a three-week interval between repeat assessments, κ range 0.69–0.914, p < 0.001.


      In this representative validation cohort there was substantial agreement between observers when assessing a diverse range of bone defects following long bone open trauma, with highly reproducible assessments by both orthopaedic surgeons and trainee orthopaedic surgeons alike on an internal level. The classification scheme is based on conventional orthogonal radiographs and requires no sophisticated technology, and is therefore pragmatic and applicable to secondary, tertiary and quaternary levels of care for trauma patients.

      Level of Evidence



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