<![CDATA[Journal of Orthopaedic & Sports Physical Therapy - Josh Tome, MS]]> http://www.jospt.org/joshtome Wed, 30 Apr 2008 09:05:25 EST 0 Comparison of Changes in Posterior Tibialis Muscle Length Between Subjects With Posterior Tibial Tendon Dysfunction and Healthy Controls During Walking http://www.jospt.org/issues/articleID.1320/article_detail.asp Christopher Neville, Adolph Flemister, Josh Tome, Jeff R. Houck
STUDY DESIGN: Case control study. OBJECTIVE: To compare posterior tibialis (PT) length between subjects with stage II posterior tibial tendon dysfunction (PTTD) and healthy controls during the stance phase of gait. BACKGROUND: The abnormal kinematics demonstrated by subjects with stage II PTTD are presumed to be associated with a lengthened PT musculotendon, but this relationship has not been fully explored. METHODS AND MEASURES: Seventeen subjects with stage II PTTD and 10 healthy controls volunteered for this study. Subject-specific foot kinematics were collected using 3-D motion analysis techniques for input into a general model of PT musculotendon length (PTLength). The kinematic inputs included hindfoot eversion/inversion (HF Ev/Inv), forefoot abduction/adduction (FF Ab/Add), forefoot plantar flexion/dorsiflexion (FF Pf/Df), and ankle plantar flexion/dorsiflexion (Ankle Pf/Df). To estimate the change in PTLength from neutral the following was used: PTLength = 0.401(HF Ev/Inv) + 0.270(FF Ab/Add) + 0.137(FF Pf/Df) + 0.057(Ankle Pf/Df). Positive values indicated lengthening from the subtalar neutral (STN) position, while negative values indicated shortening relative to the STN position. A 2-way analysis of variance (ANOVA) model was used to compare PTLength between groups across the stance phases of walking (loading response, midstance, terminal stance, and preswing). Also, a 2-way ANOVA was used to assess the foot kinematics that contributed to alterations in PTLength. The Short Musculoskeletal Functional Assessment Index and Mobility subscale were used to compare function and mobility. RESULTS: PTLength was significantly greater (lengthened) relative to the STN position in the PTTD group compared to the control group across all phases of stance, with the greatest between-group difference in PTLength occurring during preswing. The greater PTLength in subjects with PTTD compared to controls was principally attributed to significantly greater HF Ev/Inv during loading response (P=.014) and midstance (P=.015). During terminal stance and preswing, each kinematic input to estimate PTLength contributed to lengthening (main effect, P=.03 and P=.01, respectively). Subjects with PTTD with abnormally greater PTLength reported significantly lower function (P = .04) and mobility (P = .03) compared to subjects with PTTD with normal PTLength during walking. CONCLUSIONS: The greater PTLength, as determined from foot kinematics, suggests the PT musculotendon is lengthened in subjects with stage II PTTD, compared to healthy controls. The amount of lengthening is not dependent on the phase of gait; however, different foot kinematics contribute to PTLength across the stance phase. Targeting these foot kinematics may limit lengthening of the PT musculotendon. Subjects with excessive PT lengthening experience a decrease in function.

J Orthop Sports Phys Ther 2007;37(11):661-669, published online 12 July 2007. doi:10.2519/jospt.2007.2539

KEY WORDS:  foot kinematics, pronation, tendinopathy, walking

]]> http://www.jospt.org/issues/articleID.1320/article_detail.asp Comparison of Foot Kinematics Between Subjects With Posterior Tibialis Tendon Dysfunction and Healthy Controls http://www.jospt.org/issues/articleID.1160/article_detail.asp Josh Tome, Deborah A. Nawoczenski, Adolph Flemister, Jeff R. Houck

Study Design: A 2 × 4 mixed-design ANOVA with a fixed factor of group (posterior tibialis tendon dysfunction [PTTD] and asymptomatic controls), and a repeated factor of phase of stance (loading response, midstance, terminal stance, and preswing).
Objective: To compare 3-dimensional stance period kinematics (rearfoot eversion/inversion, medial longitudinal arch [MLA] angle, and forefoot abduction) of subjects with stage II PTTD to asymptomatic controls.
Background: Abnormal foot postures in subjects with stage II PTTD are clinical indicators of disease progression, yet dynamic investigations of forefoot, midfoot, and rearfoot kinematic deviations in this population are lacking.
Methods: Fourteen subjects with stage II PTTD were compared to 10 control subjects with normal arch index values. Subjects were matched for age, gender, and body mass index. A 5-segment, kinematic model of the leg and foot was tracked using an Optotrak Motion Analysis System. The dependent kinematic variables were rearfoot inversion/eversion, forefoot abduction/adduction, and the MLA angle. An ANOVA model was used to compare kinematic variables between groups across 4 phases of stance.
Results: Subjects with PTTD demonstrated significantly greater rearfoot eversion (P = .042), MLA angle (P = .008) and forefoot abduction angles (P<.005) during specific phases of stance. Subjects with PTTD demonstrated significantly greater rearfoot eversion (P<.004) and MLA angles (P<.009) by 6.2° and 8.0°, respectively, during loading response when compared to controls. During preswing, the subjects with PTTD demonstrated a significantly greater MLA angle (P<.002) and a forefoot abduction angle (P<.001) which exceeded that of the controls by 10.0°.
Conclusions: The abnormal kinematics observed at the rearfoot, midfoot, and forefoot across all phases of stance implicate a failure of compensatory muscle and secondary ligamentous support to control foot kinematics in subjects with stage II PTTD.

J Orthop Sports Phys Ther. 2006;36(9):635-644. doi:10.2519/jospt.2006.2293

Key Words: biomechanics, foot kinematics, tendinopathy, tendonitis

]]> http://www.jospt.org/issues/articleID.1160/article_detail.asp