Restriction of passive range of motion in 10 different ankle braces

Eils E, Kollmeier G, Demming C, Thorwesten L, Völker K, Rosenbaum D

Abstract in digital collection (conference)

Abstract

lntroduction: Ankle braces are widely used in sports to prevent recurrent ankle sprains. Their main purpose is to provide the necessary stability in order to prevent excessive joint motion. To attain stability some braces use plastic parts (rigids) others systems of different straps (non-rigids). The aim of this study was to determirie the restriction of passive range of motion (ROM) in 10 different braces in comparison to the joint mobiiity without brace in the three primary directions of rotation. Materials and methods: 26 subjects with chronic instability of the ankle joint participated in the study (15 female, 11 male, 24.1±2.8 years, 71.5±12.3 weight, 177.1±8.7 height). A mechanical apparatus was developed to measure the mobility of the ankle joint complex in three planes with a standardized torque. Subjects lay supine with the affected leg fixed in the apparatus, the foot placed on a foot plate and the tibia fixed at two points. Rotation axes for plantar/dorsiflexion, inversion/eversion and, internal/external rotation were set perpendicular to each other in alignment with the intermalleolar axis, the long axis of the foot on the level of the estimated location of the subtalar joint and the longitudinal axis of the tibia, respectively. The same position was used for one subject when testing all braces. To determine individual torque, the leg was fixed without braces and rotated in each direction to the limits of comfort. The maximum torque for each direction was then used for all conditions and the rotational displacement were measured with potentiometers fixed to the axes. Braces were applied to subject' s leg as suggested by the manufacturer by the same investigator. One shoe model was used in these investigations and the order of testing conditions was randomized. Five trials for each direction were measured and the individual means were calculated. For statistical analysis a repeated measures Anova with the alpha-level set to 5% and the Scheffé test for post-hoc corriparisons was used. Results: Under 'native' conditions we measured mean angles of 29.3±11.3° for inversion, 31.4±19.5° for plantarflexion and 26.1±16,5° for internal rotation with mean torques of 6.6±1.8 Nm, 6.8±2.9 Nm and 4.9±2.0 Nm, respectively. All used braces restricted ROM significantly in all directions compared to the no-brace condition (Fig 1). The most pronounced reduction in range of motion was obtained for inversion where the most and._ less effective model show passive restriction to 36% and 56% from 'native' condition. Four models show similarly low values (01, 03, 05, 09 - all rigids), four models higher values (02, 04, 06, 08 ·- rigids" and non rigids). The differences between these groups were significant. For plantarflexion, braces show pronounced differences in restriction of motion (22% - 78% ). Most rigid braces have low vahies (01, 03, 05, 09), the highest values are from non- rigid braces (04, 08). For internal rotation, the results are more consistent and cannot be separated into rigid and non rigid ones. Discussion and conclusions: The tested braces show different characteristics in restricting ROM in inversion, plantarflexion and internal rotation. For inversion, rigid braces generally seem to restrict ROM more effectively than non rigid ones, but most of them also liinit the amount of plantarflexion and internal rotation. When selecting braces for prevention of recurrent ankle sprains; those models that reveal a good combination of restriction of all components appear most suitable.

Details zur Publikation

Publisher: Patrick J. Prendergast, T. Clive Lee, Alun J. Carr
Book title: Proceedings of the 12th Conference of the European Society of Biomechanics: Incorporating Symposia on Biofluid Mechanics, Microdamage in Bone, Implant Biomaterials, Musculoskeletal Loading, Mechanobiology, and Walking Motion:
Release year: 2000
Publishing company: Royal Academy of Medicine in Ireland
ISBN: 0953880907, 9780953880904
Language in which the publication is written: English
Event: 2000