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Foot Ankle Int. 2018 Sep;39(9):1056-1061. doi: 10.1177/1071100718778022. Epub 2018 Jun 4.

Vancouver Foot and Ankle WNS (Wound, Nerve, and Systemic) Classification System for Foot and Ankle Orthopedic Surgery.

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1 Department of Orthopaedics, University of British Columbia, St. Paul's Hospital, Partner, Footbridge Centre for Integrated Foot and Ankle Care.
2 Rosalind Franklin University of Medicine, Chicago Medical School, Chicago, IL, USA.
3 Mayfair Radiology, Department of Radiology, University of Calgary, Calgary, AB, Canada.
4 Orthopaedic Foot and Ankle Surgeon, University Health Network, University of Toronto, Toronto Western Hospital, Toronto, ON, Canada.
5 Department of Orthopaedics and Rehabilitation, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.
6 Department of Orthopaedics, University of Iowa Hospitals and Clinics, Iowa City, IA, USA.
7 James R. Urbaniak, MD, Sports Sciences Institute, Duke University, Durham, NC, USA.



Adverse events require consistent recording to determine the effect of alternate treatments. This study was undertaken to evaluate the Vancouver Foot and Ankle WNS complication scale to capture complications (W: wound, N: nerve, S: systemic) to assist in outcome recording.


Interrater reliability was tested in 2 settings: (1) between 2 blinded clinicians in a live clinical setting and (2) between 8 orthopedic surgeons using case vignettes based on a retrospective analysis of 500 foot and ankle procedures performed at the Toronto Western Hospital, Department of Orthopaedics. The intrarater reliability of the WNS scale was tested in a single rater using the case vignettes. Inter- and intrarater reliability were assessed using the Fleiss and Cohen weighted kappa ( k), respectively and 95% confidence intervals (CIs). There was adequate power over 0.8.


In the live clinical setting, the Cohen weighted k (95% CI) values for the W (0.935 [0.862, 1.01]), N (0.914 [0.752, 1.08]), and S (1 [1, 1]) parameters, indicating a near perfect level of agreement between raters. In the broader community of professional foot and ankle surgeons, the Fleiss k values (95% CI) had moderate agreement for the W (0.712 [0.688, 0.735]), N (0.775 [0.738, 0.811]), and high agreement for S (0.834 [0.802, 0.866]) parameters based on case vignettes. However, the Fleiss k values continued to indicate moderate to strong agreement between raters for all parameters.


The WNS scale provided a standardized method of measuring foot and ankle surgical complications. There was at least moderate-strong interrater agreement for all parameters measured on case vignettes and excellent concordance in the live setting.


Level III, comparative series.


classification system; foot and ankle surgery; foot and ankle surgical complications; surgical complications

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