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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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 OF EVIDENCE: Level III, comparative series.