ABNORMAL LATERAL MALLEOLUS MORPHOLOGY AND PHYSICAL FUNCTION IN ADOLESCENT ATHLETES CLASSIFIED WITH PEAK HEIGHT VELOCITY AGE

H. Ishihara¹, N. Maeda¹, M. Komiya¹, S. Tsutsumi¹, S. Arima¹, Y. Ikuta^2,3, Y. Mikami³, Y. Urabe¹

¹Graduate School of Biomedical and Health Sciences, Hiroshima University, Department of Sports Rehabilitation, Hiroshima, Japan, ²Graduate School of Biomedical and Health Sciences, Hiroshima University, Department of Orthopedic Surgery, Hiroshima, Japan, ³Hiroshima University Hospital, Department of Rehabilitation, Hiroshima, Japan

Background: Lateral ankle sprain (LAS) is one of the most common injuries. LAS in childhood can lead to lateral malleolus avulsion fractures, additionally, bone nonunion may occur. Previous studies suggested the association with mechanical instability due to avulsion fractures and functional instability caused by mechanoreceptor impairment. Furthermore, when focusing on adolescent athletes and examining their physical function, Physical maturity needs to be considered because physical functions such as muscle strength and balance differed depending on the level of physical maturity. It is unclear how changes in physical function attributable to physical maturity affect adolescent athletes with abnormal lateral malleolus (ALM) morphology.

Purpose: The present study aimed to investigate the bone morphology of the lateral malleolus in adolescent athletes and to examine its relationship with physical functionality at different maturity levels.

Methods: A total of 77 athletes (49 boys and 28 girls) aged 10-17 years were included. The presence of ALM was assessed by observing the bone morphology of the anterior talofibular ligament attachment to the lateral malleolus with ultrasonography. All participants were classified into 3 groups based on thepeak height velocity age (PHVA): -1.0 year > PHVA (Pre-PHVA), -1.0 year ≦ PHVA ≦ +1.0 year (Mid-PHVA), and +1.0 year < PHVA (Post-PHVA). The outcome parameters were the weight-bearing ankle dorsiflexion angle, navicular drop test (NDT), foot posture index (FPI), and one-leg forward jump landing performance which was assessed by Dynamic Posture Stability Index (DPSI). The DPSI is a composite of the anteroposterior stability index (APSI), mediolateral stability index (MLSI), and vertical stability index (VSI) directions.A two-way analysis of variance was performed to compare the results of all measurements between the 3 groups and also to compare between ALM group and non-ALM group within each PHVA group. The significance level was set at p<0.05.

Results: All measurements were not different between the 3 groups based on physical maturity. Regarding the ALM group, the weight-bearing ankle dorsiflexion angle was decreased in Mid-PHVA (p<0.01), and FPI scored higher in Mid- and Post-PHVA (p<0.05). DPSI and VSI showed lower values in Mid-PHVA (p<0.05), and MLSI was lower in Mid- and Post-PHVA (p<0.05).

Conclusions: The feet with ALM in Mid- and Post-PHVA were evaluated as tending to be more pronatedfrom FPI results. Since there was no difference in NDT, pronation of the rearfoot is considered to have occurred and decreased the weight-bearing ankle dorsiflexion angle. The ALM group exhibited poorer dynamic postural stability in jump-landing in Mid- and Post-PHVA. These findings indicate that patients with ALM, who are commonly known for having a higher rate of LAS recurrence, decreased physical function directly associated with sports movements. And it leads to the understanding of the importance of prevention of LAS and coping after being injured.

Implications: This study shows the importance of using ultrasonography, and our findings suggest that the decline in dynamic postural instability in adolescent athletes with ALM was evident from Mid- to Post-PHVA.

Funding acknowledgements: We have no funding acknowledgment in this study.

Keywords:
lateral malleolus avulsion
adolescent athlete
physical maturity

Topics:
Sport & sports injuries
Orthopaedics

Did this work require ethics approval? Yes

Institution: Hiroshima university hospital

Committee: Ethics Committee of Hiroshima University Hospital

Ethics number: E-941