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M.P. Wilhelm1, T.L. Hooper2, G.H. Seeber3,2, K.L. Browne4, E. Sargent5, K.K. Gilbert2, C.R. James6, J.-M. Brismée2, O.C. Matthijs7, A. Matthijs7, P.S. Sizer Jr.2
1Tufts University School of Medicine, Medford, United States, 2Center for Rehabilitation Research, Texas Tech University Health Sciences Center, Lubbock, United States, 3University Hospital for Orthopaedics and Trauma Surgery Pius-Hospital, Medical Campus University of Oldenburg, Oldenburg, Germany, 4College of Health Sciences, University of Texas El Paso, El Paso, United States, 5University of Vermont, Department for Rehabilitation and Movement Sciences, Burlington, United States, 6Texas Tech University Health Sciences Center, Lubbock, United States, 7BOMA Physical Therapy Outpatient Clinic, Kapfenberg, Austria
Background: Subtalar joint (STJ) dysfunction can contribute to movement disturbances. Vibration energy with color Doppler imaging (VECDI) may be useful for detecting STJ stiffness changes.
Purpose: This study’s objectives were to:
(1) support proof-of-concept that VECDI could detect STJ stiffness differences;
(2) establish STJ stiffness range in asymptomatic volunteers;
(3) examine relationships between STJ stiffness and foot mobility; and
(4) assess VECDI precision and reliability for examining STJ stiffness.
(1) support proof-of-concept that VECDI could detect STJ stiffness differences;
(2) establish STJ stiffness range in asymptomatic volunteers;
(3) examine relationships between STJ stiffness and foot mobility; and
(4) assess VECDI precision and reliability for examining STJ stiffness.
Methods: After establishing cadaveric testing model proof-of-concept, STJ stiffness (threshold units, ΔTU), ankle complex passive range-of-motion (PROM) and midfoot-width-difference (MFWDiff) data were collected in 28 asymptomatic subjects in vivo. Three reliability measurements were collected per variable; Rater-1 collected on all subjects and rater-2 on the first ten subjects. Subjects were classified into three STJ stiffness groups.
Results: Cadaveric VECDI measurement intra-rater reliability was 0.80. A significantly lower STJ ΔTU (p=.002) and ankle complex PROM (p<.001) was observed during the screw fixation versus normal condition. A fair correlation (r=0.660) was observed between cadaveric ΔTU and ankle complex PROM. In vivo VECDI measurements demonstrated good intra-rater (0.76-0.84) versus poor inter-rater (-3.11) reliability. Significant positive correlations were found between STJ stiffness and both dorsum (r=.440) and posterior (r=.390) PROM. MFWDiff exhibited poor relationships with stiffness (r=.103) and either dorsum (r=.256) or posterior (r=.301) PROM. STJ stiffness ranged from 2.33 to 7.50 ΔTUs, classified subjects’ STJ stiffness as increased (n=6), normal (n=15), or decreased (n=7). Significant ANOVA main effects for group classification were found based on ΔTU (p< .001), dorsum PROM (p=.017), and posterior PROM (p=.036). Post-hoc tests revealed significant:
(1) ΔTU differences between all stiffness groups (p<.001);
(2) dorsum PROM differences between the increased versus normal (p=.044) and versus decreased (p=.017) stiffness groups; and
(3) posterior PROM differences between the increased versus decreased stiffness groups (p=.044).
A good relationship was found between STJ stiffness and dorsum PROM in the increased stiffness group (r=.853) versus poor, nonsignificant relationships in the normal (r=-.042) or decreased stiffness (r=-.014) groups.
(1) ΔTU differences between all stiffness groups (p<.001);
(2) dorsum PROM differences between the increased versus normal (p=.044) and versus decreased (p=.017) stiffness groups; and
(3) posterior PROM differences between the increased versus decreased stiffness groups (p=.044).
A good relationship was found between STJ stiffness and dorsum PROM in the increased stiffness group (r=.853) versus poor, nonsignificant relationships in the normal (r=-.042) or decreased stiffness (r=-.014) groups.
Conclusion(s): PROM may not clinically explain all aspects of joint mobility. Joint VECDI stiffness assessment should be considered as a complimentary measurement technique.
Implications: This study’s results could justify future studies for using VECDI to further understand ankle-foot mechanical properties, as well as to examine diagnostic and clinical accuracy of STJ testing and treatment approaches. Moreover, by establishing the relationship between STJ laxity and MFWDiff, connections between STJ stiffness and foot function may be better understood.
Funding, acknowledgements: No funding has been received for this study.
Keywords: Subtalar Joint, Vibration Energy with Color Doppler Imaging, Stiffness
Topic: Musculoskeletal: lower limb
Did this work require ethics approval? Yes
Institution: Texas Tech University Health Sciences Center (TTUHSC)
Committee: TTUHSC Lubbock/Odessa Institutional Review Board for Protection of Human Subjects
Ethics number: (#-L14-036)
All authors, affiliations and abstracts have been published as submitted.
