The relationship between measures of foot mobility and subtalar joint stiffness using vibration energy with color Doppler imaging-A clinical proof-of-concept validation study

• Published in: PloS one Vol. 15; no. 8; p. e0237634
• Main Authors: Wilhelm, Mark P., Hooper, Troy L., Seeber, Gesine H., Browne, Kevin L., Sargent, Elizabeth, Gilbert, Kerry K., James, C. Roger, Brismée, Jean-Michel, Matthijs, Omer C., Matthijs, Anja, Sizer, Phillip S.
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 19.08.2020; Public Library of Science (PLoS)
• Subjects: Adult; Ankle; Asymptomatic; Biology and Life Sciences; Biomechanical Phenomena; Bone implants; Cadavers; Color; Correlation; Diagnosis; Doppler effect; Doppler ultrasonography; Energy; Engineering and Technology; Feet; Female; Foot; Foot - diagnostic imaging; Foot - physiopathology; Health sciences; Humans; Hypotheses; In vivo methods and tests; Indexing; Joint diseases; Joint Diseases - diagnostic imaging; Joint Diseases - physiopathology; Kinematics; Male; Measurement techniques; Medical examination; Medicine and Health Sciences; Mobility; Model testing; Movement; Outpatient care facilities; Physical Sciences; Physical therapy; Physiological aspects; Posture; Proof of Concept Study; Range of Motion, Articular; Rehabilitation; Reliability analysis; Reproducibility of Results; Research and Analysis Methods; Stiffness; Studies; Subtalar Joint - diagnostic imaging; Subtalar Joint - physiopathology; Ultrasonography, Doppler, Color - methods; Values; Variance analysis; Vibration; Young Adult; United States; Lubbock Texas; Austria; United States > US; Texas
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0237634

Subtalar joint (STJ) dysfunction can contribute to movement disturbances. Vibration energy with color Doppler imaging (VECDI) may be useful for detecting STJ stiffness changes. (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. 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. 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, categorizing subjects' STJ stiffness as increased (n = 6), normal (n = 15), or decreased (n = 7). Significant ANOVA main effects for 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 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. PROM may not clinically explain all aspects of joint mobility. Joint VECDI stiffness assessment should be considered as a complimentary measurement technique.