Morphological characteristics and clinical significance of os subfibulare in patients with chronic ankle instability_Chinese Journal of Reparative and Reconstructive Surgery

Authors：

DUAN Xinfang ¹ , WANG Junqiu ¹ , CHEN Jianyao ² , LI Zheheng ² , ZHAO Yue ² , ZHOU Xin ¹ ,  ZHANG Lei ^1,2,3

1. Department of Orthopedics, the Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou Sichuan, 646000, P. R. China;
2. School of Physical Education, Southwest Medical University, Luzhou Sichuan, 646000, P. R. China;
3. Luzhou Key Laboratory of Orthopedic Disorders, Luzhou Sichuan, 646000, P. R. China;

Corresponding?author：

ZHANG Lei, Email: zhanglei0722@swmu.edu.cn

Keywords：

Chronic ankle instability; os subfibulare; morphology; anterior talofibular ligament; imaging

DOI：

10.7507/1002-1892.202511013

Video：

Export PDF Favorites Scan Get Citation

Abstract Full text Figures/Tables Video References Cited by

Objective To investigate the morphological characteristics of the os subfibulare (OSF) and evaluate its clinical association with chronic ankle instability (CAI). Methods Imaging data of 130 patients with OSF between January 2015 and August 2025 were retrospectively analyzed, including 82 males and 48 females with a mean age of 30.6 years (range, 10-80 years). Patients were divided into CAI group (n=74) and non-CAI group (n=56). X-ray films were used for screening, while CT images were used to measure the parameters related to the shape and spatial location of the OSF, including the maximum diameter, maximum area, distance from the OSF center to the fibular tip, distance from OSF to the talus, and the angle between the OSF and the fibular long axis. OSFs were classified as regular or irregular. MRI categorized OSF location into three zones based on ligament attachment sites: zone Ⅰ [anterior talofibular ligament (ATFL)], zone Ⅱ (calcaneofibular ligament), and zone Ⅲ (posterior talofibular ligament). Bone interface fluid signal, bone marrow edema, and ATFL injury were recorded. The patients with CAI were stratified and analyzed to compare the differences in the location, shape and spatial localization of the OSF (the maximum diameter of OSF, the distance from the OSF center to the fibular tip, the angle between the OSF and the fibular long axis) and MRI signs between different genders and between different affected sides. Results CT measurements showed that, compared with the non-CAI group, the CAI group exhibited differences in spatial localization of the OSF. The distance from the OSF center to the fibular tip was significantly greater in the CAI group (P<0.05), whereas the distance from OSF to the talus, and the angle between the OSF and the fibular long axis showed no significant difference (P>0.05). Regarding morphology and size, the maximum diameter of OSF was significantly larger in the CAI group (P<0.05), while no significant difference was found in maximum area of OSF or morphological type (P>0.05). MRI findings showed that OSFs were predominantly located in zone Ⅰ in both groups, followed by zones Ⅱ and Ⅲ. There was no significant difference in distribution between groups (P>0.05). The incidences of bone marrow edema, bone interface fluid signal, and ATFL injury were significantly higher in the CAI group than in the non-CAI group (P<0.05). Within the CAI group, no significant difference was observed between genders or affected sides in terms of OSF location, morphology, spatial parameters, or MRI findings (P>0.05). Conclusion Patients with CAI showed a larger maximum OSF diameter and a greater distance from the OSF center to the fibular tip, and were more frequently accompanied by MRI findings such as bone marrow edema, bone interface fluid signal, and ATFL injury. These imaging characteristics may help evaluate the relationship between OSF and CAI from an imaging perspective.

Citation： DUAN Xinfang, WANG Junqiu, CHEN Jianyao, LI Zheheng, ZHAO Yue, ZHOU Xin, ZHANG Lei. Morphological characteristics and clinical significance of os subfibulare in patients with chronic ankle instability. Chinese Journal of Reparative and Reconstructive Surgery, 2026, 40(4): 584-590. doi: 10.7507/1002-1892.202511013 Copy

1.	Lee DJ, Shin HS, Lee JH, et al. Morphological characteristics of os subfibulare related to failure of conservative treatment of chronic lateral ankle instability. Foot Ankle Int, 2020, 41(2): 216-222.
2.	Kim BS, Woo S, Kim JY, et al. Radiologic findings for prediction of rehabilitation outcomes in patients with chronic symptomatic os subfibulare. Radiol Med, 2017, 122(10): 766-773.
3.	Pill SG, Hatch M, Linton JM, et al. Chronic symptomatic os subfibulare in children. J Bone Joint Surg (Am), 2013, 95(16): e115(1-6). 115-111. doi: 10.2106/JBJS.L.00847.
4.	Kono T, Ochi M, Takao M, et al. Symptomatic os subfibulare caused by accessory ossification: a case report. Clin Orthop Relat Res, 2002, (399): 197-200.
5.	Lui TH, Wan YTO. Arthroscopic stabilization of unstable os subfibulare. Arthrosc Tech, 2019, 8(9): e1007-e1012.
6.	Monden S, Hasegawa A, Hio N, et al. Arthroscopic excision of separated ossicles of the lateral malleolus. J Orthop Sci, 2013, 18(5): 733-739.
7.	Kim SH, Lee SH, Choi SJ, et al. Is it necessary to remove small fibular ossicles during an arthroscopic modified Brostr?m operation for chronic lateral ankle instability? BMC Musculoskelet Disord, 2025, 26(1): 383. doi: 10.1186/s12891-025-08546-7.
8.	張珉源, 李愷泉, 楊鴻邁, 等. 關節鏡下距腓前韌帶損傷增強修復研究進展. 中國修復重建外科雜志, 2025, 39(12): 1600-1605.
9.	Xu N, Sun P, Zhang J, et al. Enhanced subfibular ossicle diagnosis: CT-MRI integration of morphology and ligament attachments. Insights Imaging, 2025, 16(1): 252. doi 10.1186/s13244-025-02138-8.
10.	Xiong S, Zhong R, Li Y, et al. Comparison of clinical outcomes between ligament repair and reconstruction after excision of large os subfibulare with diameter ≥10 mm: A propensity score-matched analysis. Am J Sports Med, 2025, 53(14): 3452-3461.
11.	Kim BS, Choi WJ, Kim YS, et al. The effect of an ossicle of the lateral malleolus on ligament reconstruction of chronic lateral ankle instability. Foot Ankle Int, 2010, 31(3): 191-196.
12.	Sakurai S, Nakasa T, Ikuta Y, et al. Morphological characteristics of lateral ankle ligament injuries associated with recurrent instability after arthroscopic repair for chronic ankle instability: 3D volume rendering MRI model analysis. Orthop J Sports Med, 2025, 13(11): 23259671251387340. doi: 10.1177/23259671251387340.
13.	Ahn HW, Lee KB. Comparison of the modified Brostr?m procedure for chronic lateral ankle instability with and without subfibular ossicle. Am J Sports Med, 2016, 44(12): 3158-3164.
14.	袁承杰, 朱根銳, 王之楓, 等. 慢性踝關節外側不穩定的診療策略. 中華醫學雜志, 2020, 100(29): 2254-2257.
15.	Szaro P, Ghali Gataa K, Polaczek M, et al. The double fascicular variations of the anterior talofibular ligament and the calcaneofibular ligament correlate with interconnections between lateral ankle structures revealed on magnetic resonance imaging. Sci Rep, 2020, 10(1): 20801. doi: 10.1038/s41598-020-77856-8.
16.	Kobayashi T, Suzuki E, Yamazaki N, et al. Fibular malalignment in individuals with chronic ankle instability. J Orthop Sports Phys Ther, 2014, 44(11): 872-878.
17.	謝承志. 踝關節外側韌帶解剖學進展. 中國臨床解剖學雜志, 2023, 41(3): 367-370.
18.	熊士凱, 史尉利, 王安鴻, 等. 腓骨遠端撕脫骨折的影像學診斷: 踝關節X線與CT三維重建的比較. 北京大學學報 (醫學版), 2023, 55(1): 156-159.
19.	王卓, 蒙昭宇, 杜婧菡, 等. 脛腓骨下前韌帶下束的解剖學特征及臨床意義. 中國臨床解剖學雜志, 2025, 43(3): 274-277.
20.	張磊, 王俊秋, 李文, 等. 基于MRI的脛距前脂肪墊分型與距腓前韌帶損傷程度的相關性分析. 中國修復重建外科雜志, 2025, 39(3): 271-277.
21.	姚涵, 田愛現, 馬劍雄, 等. 力學刺激對關節液理化性質的影響及其在骨關節炎中的作用. 中國修復重建外科雜志, 2025, 39(7): 903-911.
22.	Chamorro-Moriana G, Perez-Cabezas V, Benitez-Lugo M. Effectiveness of functional or biomechanical bandages with athletic taping and kinesiotaping in subjects with chronic ankle instability: a systematic review and meta-analysis. EFORT Open Rev, 2024, 9(2): 94-106.
23.	Wei S, Tang M, Li W, et al. Arthroscopic suture-bridge repair technique for an avulsion of the talar insertion of the anterior talofibular ligament. J Foot Ankle Surg, 2022, 61(4): 689-694.

1. Lee DJ, Shin HS, Lee JH, et al. Morphological characteristics of os subfibulare related to failure of conservative treatment of chronic lateral ankle instability. Foot Ankle Int, 2020, 41(2): 216-222.
2. Kim BS, Woo S, Kim JY, et al. Radiologic findings for prediction of rehabilitation outcomes in patients with chronic symptomatic os subfibulare. Radiol Med, 2017, 122(10): 766-773.
3. Pill SG, Hatch M, Linton JM, et al. Chronic symptomatic os subfibulare in children. J Bone Joint Surg (Am), 2013, 95(16): e115(1-6). 115-111. doi: 10.2106/JBJS.L.00847.
4. Kono T, Ochi M, Takao M, et al. Symptomatic os subfibulare caused by accessory ossification: a case report. Clin Orthop Relat Res, 2002, (399): 197-200.
5. Lui TH, Wan YTO. Arthroscopic stabilization of unstable os subfibulare. Arthrosc Tech, 2019, 8(9): e1007-e1012.
6. Monden S, Hasegawa A, Hio N, et al. Arthroscopic excision of separated ossicles of the lateral malleolus. J Orthop Sci, 2013, 18(5): 733-739.
7. Kim SH, Lee SH, Choi SJ, et al. Is it necessary to remove small fibular ossicles during an arthroscopic modified Brostr?m operation for chronic lateral ankle instability? BMC Musculoskelet Disord, 2025, 26(1): 383. doi: 10.1186/s12891-025-08546-7.
8. 張珉源, 李愷泉, 楊鴻邁, 等. 關節鏡下距腓前韌帶損傷增強修復研究進展. 中國修復重建外科雜志, 2025, 39(12): 1600-1605.
9. Xu N, Sun P, Zhang J, et al. Enhanced subfibular ossicle diagnosis: CT-MRI integration of morphology and ligament attachments. Insights Imaging, 2025, 16(1): 252. doi 10.1186/s13244-025-02138-8.
10. Xiong S, Zhong R, Li Y, et al. Comparison of clinical outcomes between ligament repair and reconstruction after excision of large os subfibulare with diameter ≥10 mm: A propensity score-matched analysis. Am J Sports Med, 2025, 53(14): 3452-3461.
11. Kim BS, Choi WJ, Kim YS, et al. The effect of an ossicle of the lateral malleolus on ligament reconstruction of chronic lateral ankle instability. Foot Ankle Int, 2010, 31(3): 191-196.
12. Sakurai S, Nakasa T, Ikuta Y, et al. Morphological characteristics of lateral ankle ligament injuries associated with recurrent instability after arthroscopic repair for chronic ankle instability: 3D volume rendering MRI model analysis. Orthop J Sports Med, 2025, 13(11): 23259671251387340. doi: 10.1177/23259671251387340.
13. Ahn HW, Lee KB. Comparison of the modified Brostr?m procedure for chronic lateral ankle instability with and without subfibular ossicle. Am J Sports Med, 2016, 44(12): 3158-3164.
14. 袁承杰, 朱根銳, 王之楓, 等. 慢性踝關節外側不穩定的診療策略. 中華醫學雜志, 2020, 100(29): 2254-2257.
15. Szaro P, Ghali Gataa K, Polaczek M, et al. The double fascicular variations of the anterior talofibular ligament and the calcaneofibular ligament correlate with interconnections between lateral ankle structures revealed on magnetic resonance imaging. Sci Rep, 2020, 10(1): 20801. doi: 10.1038/s41598-020-77856-8.
16. Kobayashi T, Suzuki E, Yamazaki N, et al. Fibular malalignment in individuals with chronic ankle instability. J Orthop Sports Phys Ther, 2014, 44(11): 872-878.
17. 謝承志. 踝關節外側韌帶解剖學進展. 中國臨床解剖學雜志, 2023, 41(3): 367-370.
18. 熊士凱, 史尉利, 王安鴻, 等. 腓骨遠端撕脫骨折的影像學診斷: 踝關節X線與CT三維重建的比較. 北京大學學報 (醫學版), 2023, 55(1): 156-159.
19. 王卓, 蒙昭宇, 杜婧菡, 等. 脛腓骨下前韌帶下束的解剖學特征及臨床意義. 中國臨床解剖學雜志, 2025, 43(3): 274-277.
20. 張磊, 王俊秋, 李文, 等. 基于MRI的脛距前脂肪墊分型與距腓前韌帶損傷程度的相關性分析. 中國修復重建外科雜志, 2025, 39(3): 271-277.
21. 姚涵, 田愛現, 馬劍雄, 等. 力學刺激對關節液理化性質的影響及其在骨關節炎中的作用. 中國修復重建外科雜志, 2025, 39(7): 903-911.
22. Chamorro-Moriana G, Perez-Cabezas V, Benitez-Lugo M. Effectiveness of functional or biomechanical bandages with athletic taping and kinesiotaping in subjects with chronic ankle instability: a systematic review and meta-analysis. EFORT Open Rev, 2024, 9(2): 94-106.
23. Wei S, Tang M, Li W, et al. Arthroscopic suture-bridge repair technique for an avulsion of the talar insertion of the anterior talofibular ligament. J Foot Ankle Surg, 2022, 61(4): 689-694.

Chinese Journal of Reparative and Reconstructive Surgery

Morphological characteristics and clinical significance of os subfibulare in patients with chronic ankle instability

Abstract Full text Figures/Tables Video References Cited by

Previous Article

Next Article

Format

Content