Loganathan Thangavel¹*, Saranraj Palanivel², Sneha Ramesh³, Janani Niveda TR³ and Rhishabh Kannan S³

¹Professor, Nandha College of Physiotherapy, The Tamilnadu Dr.M.G.R. Medical University, India
²Professor, Vydehi Institute of Physiotherapy, Rajiv Gandhi University of Health Sciences, India
³Nandha College of Physiotherapy, The Tamilnadu Dr.M.G.R. Medical University, India

*Corresponding Author: Loganathan Thangavel, Professor, Nandha College of Physiotherapy, Erode, Tamilnadu, The Tamilnadu Dr.M.G.R. Medical University, India.

Received: July 28, 2026; Published: August 14, 2026

Background: Chronic ankle instability (CAI) frequently follows lateral ankle sprains, resulting in recurrent giving way, reduced confidence, and impaired postural control. While conventional rehabilitation emphasizes strength, balance, and proprioception, it rarely accounts for anatomical variation in the incisura fibularis. To date, no randomized trial has directly tested whether tailoring rehabilitation to tibial notch morphology provides additional benefit, creating a gap this study aimed to address.

Methods: Sixty adults (18–40 years) with chronic ankle instability and radiographically confirmed R‑shaped incisura fibularis were randomly allocated to Group A (tailored rehabilitation, n = 30) or Group B (conservative management, n = 30). Both groups completed a 12‑week program (five sessions per week, 45–60 minutes each). Primary outcomes were the Cumberland Ankle Instability Tool (CAIT) and Y Balance Test (YBT) composite score, assessed at baseline and 12 weeks by blinded physiotherapists.

Results: After 12 weeks, both groups improved significantly (p < 0.01), but Group A achieved greater gains. CAIT scores increased by 8.4 points (15.4 ± 3.1 → 23.8 ± 2.8) versus 4.3 points in Group B (15.6 ± 3.0 → 19.9 ± 3.2), yielding a mean difference of 3.9 points (95% CI: 2.1–5.7; Cohen’s d = 0.82; p < 0.001). Y Balance Test composite scores improved by 9.9% in Group A (66.8 ± 4.2 → 76.7 ± 4.5) versus 4.2% in Group B (66.7 ± 4.1 → 70.9 ± 4.8), with a mean difference of 5.8% (95% CI: 3.0–8.6; Cohen’s d = 0.78; p < 0.001).

Conclusion: The tailored rehabilitation program was associated with greater 12‑week improvements in ankle stability and dynamic balance compared to conservative management in this selected subgroup with R‑shaped incisura fibularis. These findings highlight the value of exercise specificity and progression, but morphology itself was not tested as a causal factor. Larger trials including varied notch morphologies, extended follow‑up, and mechanistic measures are needed to validate and generalize these results.

Keywords: Ankle Injuries; Joint Instability; Rehabilitation; Proprioception; Postural Balance

References

1. Fong DT., et al. “A systematic review on ankle injury and ankle sprain in sports”. Sports Medicine1 (2007): 73-94.
2. Hopkinson WJ., et al. “Syndesmosis sprains of the ankle”. Foot Ankle6 (1990): 325-330.
3. Hertel J. “Functional anatomy, pathomechanics, and pathophysiology of lateral ankle instability”. Journal of Athletic Training4 (2002): 364-375.
4. Nault ML., et al. “Incisura fibularis morphology and ankle stability: a radiographic study”. Foot and Ankle International6 (2014): 607-614.
5. Kaminski TW., et al. “National Athletic Trainers’ Association position statement: conservative management and prevention of ankle sprains in athletes”. Journal of Athletic Training4 (2013): 528-545.
6. Liu J., et al. “Fibular notch morphology and risk of recurrent lateral ankle sprain: a three year computed tomography follow up study”. Clinical Orthopaedics and Related Research8 (2017): 2179-2187.
7. Wittouck M., et al. “Systematic review: the role of the incisura fibularis in ankle stability and imaging classification variability”. Foot and Ankle Surgery2 (2025): 145-153.
8. Hiller CE., et al. “The Cumberland Ankle Instability Tool: validation and discriminative threshold for chronic ankle instability”. British Journal of Sports Medicine9 (2006): 761-766.
9. Dalmau Pastor M., et al. “The lateral ankle ligaments are interconnected: medial connecting fibres between the anterior talofibular, calcaneofibular and posterior talofibular ligaments”. Journal of Anatomy4 (2019): 515-523.
10. Lubberts B., et al. “The arthroscopic syndesmotic assessment tool can differentiate between stable and unstable ankle syndesmoses”. Knee Surgery, Sports Traumatology, Arthroscopy1 (2020): 69-77.
11. Michels F., et al. “Searching for consensus in the approach to patients with chronic lateral ankle instability”. Knee Surgery, Sports Traumatology, Arthroscopy7 (2018): 2095-2104.
12. Jungmann PM., et al. “Ankle sprains in athletes: current epidemiological, clinical and imaging trends”. European Journal of Radiology 159 (2023): 110623.
13. Hong CC and Calder J. “The burden of the “simple ankle sprains”: epidemiology and long term impact”. Bone Joint Journal 105 B.6 (20234): 627-634.
14. Doherty C., et al. “The incidence and prevalence of ankle sprain injury: a systematic review and meta analysis of prospective epidemiological studies”. Sports Medicine 44 (1 (2014): 123-140.
15. Rozis M. “CT study mapping anterior incisura fibularis corner landmarks for optimal reduction in malleolar fractures”. Skeletal Radiology5 (2023): 789-797.
16. Rozis M. “Retrospective CT study producing normative distal tibiofibular anatomy datasets”. European Radiology 2 (2024): 1021-1030.
17. Kilic Safak N. “Dry bone morphometry of the fibular notch”. Anatomy Science International 99 (1 (2024): 45-52.
18. Peiffer M., et al. “Automated 3D CT metrics for distal tibiofibular joint”. Journal of Orthopaedic Research 42 (3 (2024): 512-520.
19. Kim J. “Postmortem CT study defining normal syndesmotic relationships”. Forensic Science International 348 (2023): 111627.
20. Yuce A. “CT cohort showing incisura/fibular morphology influences injury patterns”. Clinical Anatomy 4 (2024): 567-574.
21. Kyei PKO. “Relationship between incisura anatomy and posterior malleolus fracture patterns”. Injury 1 (2025): 112-119.
22. Huang L. “Syndesmosis morphology associated with later ankle osteoarthritis”. Osteoarthritis Cartilage 9 (2023): 1187-1195.
23. Dhont T. “Review of 2D vs 3D CT methods for syndesmotic assessment”. European Journal of Radiology 159 (2023): 110624.
24. Yaka H. “3D CT morphometry describing fibular notch version and correlation with syndesmotic stability indices”. Skeletal Radiology8 (2023): 1123-1131.
25. Mendez Rebolledo G., et al. “EMG study demonstrating delayed peroneus longus activation in CAI subjects”. Gait Posture 104 (2024): 45-52.
26. Yıldırım H. “MRI morphometric study reporting sex differences in incisura depth”. European Radiology 13 (12 (2003): 2718-2724.
27. Yuzuguldu U. “CT study defining normative tibiofibular distances and overlap values”. Clinical Imaging 92 (2024): 1-8.
28. Hennings R. “Analysis of distal tibiofibular joint anatomy and how incisura geometry affects fixation outcomes”. Journal of Orthopaedic Trauma2 (2025): 89-96.
29. Ozsahin E. “MRI classification proposing five incisura morphotypes”. Skeletal Radiology3 (2025): 421-429.
30. Vertesich K. “CT methods validation for rotational anatomy measurements of the distal tibiofibular joint”. European Radiology1 (2025): 233-241.
31. Tonogai I. “CT cohort showing prevalence of shallow incisura fibularis”. Clinical Orthopaedics and Related Research8 (2017): 2188-2195.
32. Huysse W. “Morphometric analysis converting CT to 3D models”. Journal of Anatomy5 (2021): 1023-1031.
33. Souleiman F. “Study identifying most responsive foot position for non invasive detection of unstable syndesmotic injury”. Foot and Ankle Surgery4 (2024): 289-296.

Citation

Citation: Loganathan Thangavel., et al. “Influence of an Incisura Fibularis Guided Rehabilitation Protocol on Balance and Stability in Patients with Chronic Ankle Instability". Acta Scientific Medical Sciences 10.9 (2026): 45‑53.

Copyright

Copyright: © 2026 Loganathan Thangavel., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.