Novel Radiographic Measurement Method for an Anterior Drawer Stress View of Plain Radiographs in Patients with Chronic Lateral Ankle Instability: Fibular Tip to Talar Neck Measurements
10.14193/jkfas.2026.30.2.61
- Author:
Jae-Wook PARK
1
;
Soonmin KWON
;
Yong Chan KIM
;
Hyun-Woo PARK
Author Information
1. Department of Orthopedic Surgery, Dankook University Hospital, Dankook University College of Medicine, Cheonan, Korea
- Publication Type:Original Article
- From:Journal of Korean Foot and Ankle Society
2026;30(2):61-68
- CountryRepublic of Korea
- Language:English
-
Abstract:
Purpose:Stress radiographs have long been used to evaluate chronic lateral ankle instability. Several measurement methods exist, but their diagnostic value remains controversial. This paper introduces a new measurement method for stress radiographs, the fibular tip to talar neck (FTN) method, and compares it with established methods to assess its diagnostic accuracy and reliability.
Materials and Methods:Forty-one patients who underwent a modified Broström procedure for chronic lateral ankle instability were included. Lateral standing and anterior drawer radiographs were analyzed using two conventional methods (methods I and II) and the novel FTN method. The contralateral unaffected side served as an internal control. The diagnostic accuracy was evaluated using receiver operating characteristic curve analysis. The intra-observer and inter-observer reliability were assessed using intraclass correlation coefficients (ICCs).
Results:Using the FTN method, the mean gap on the affected side (14.39±4.79 mm) was significantly greater than on the contralateral side (10.24±4.19 mm, p<0.001). The side-to-side difference (SSD) was significantly higher in the FTN method (4.14±2.94 mm) compared to methods I (0.89±1.94 mm) and II (0.91±1.78 mm, p<0.001). The FTN method showed a balanced diagnostic performance with an area under the curve of 0.743 and an optimal cut-off of 13.5 mm. The intra-observer and inter-observer reliability were good for all methods. The intra-observer and inter-observer ICCs for the FTN method were 0.858 and 0.783, respectively.
Conclusion:The FTN method provides a reliable and reproducible measure of chronic lateral ankle instability. The method facilitates a more intuitive diagnosis compared to conventional techniques by providing a larger numerical differentiation (SSD) and a statistically balanced threshold.
