Validity and reliability of the Unified Classification System applied to periprosthetic femur fractures: a comparison with the Vancouver system

Abstract

Objective: The Unified Classification System (UCS) presents itself as an evolution of the Vancouver Classification (VCS) for the evaluation of periprosthetic fractures of the proximal femur (PPF). The aim of our study was to highlight any loss of reproducibility or validity of the new classification system, compared to the previous one.

Material and methods: We tested the interobserver and intraobserver agreement using 40 PPF clinical cases. Each classifying subtype of the UCS and VCS was present in at least two cases. Six experienced hip surgeons (Senior Surgeon, SS) and 5 surgeons in training (Junior Surgeon, JS) classified the clinical cases, using VCS and UCS. The validity of both classifications was then tested with intraoperative surveys.

Results: The mean κ value for interobserver agreement for the VCS in the JS group was 0.65 and 0.81 for the SS group. The mean κ value for interobserver agreement for the UCS in the JS group was 0.63 and 0.65 for the SS group. The mean κ value for intraobserver agreement for the VCS in the JS group was 0.71 and 0.73 for the SS group. The mean κ value for intraobserver agreement for the UCS in the JS group was 0.72 and 0.7 for the SS group. Validity analysis showed a moderate agreement for the VCS and a good agreement for the UCS.

Conclusion: The UCS completes the Vancouver classification, expanding it. It is reliable, despite the increase in classification categories and number of parameters to evaluate, with a slightly higher validity.

Keywords:

• Vancouver Classification System
• periprosthetic fracture
• total hip arthroplasty
• revision hip arthroplasty
• validity
• reliability
• UCS

Transparency

Declaration of funding

There is no funding to disclose.

Declaration of financial/other relationships

The authors of this manuscript have no relevant financial or other relationships to disclose. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Author contributions

All authors have contributed substantially to this study. Conceptualization: DDM, PP and CV; Data curation: VC, EMP and BZ; Formal analysis: BZ, AC and MM; Investigation: BZ, AC and VC; Methodology: DDM, AC, MM and CV; Project administration: DDM and CV; Resources: PP and CV; Software: EMP; Supervision: DDM, PP and CV; Validation: DDM, VC, EMP, BZ, AC, MM, PP and CV; Visualization: DDM, VC, EMP, BZ, AC, MM, PP and CV; Writing – original draft, DDM and BZ; Writing – review & editing, DDM, VC, EMP, BZ, AC, MM, PP and CV.

Acknowledgements

None reported.