Smita Rao

Relationships between segmental foot mobility and plantar loading in individuals with and without diabetes and neuropathy

The purpose of our study was to examine dynamic foot function during gait as it relates to plantar loading in individuals with DM (diabetes mellitus and neuropathy) compared to matched control subjects. Foot mobility during gait was examined using a multi-segment kinematic model, and plantar loading was measured using a pedobarograph in subjects with DM (N = 15), control subjects (N = 15). Pearson product moment correlation was used to assess the relationship between variables of interest. Statistical significance and equality of correlations were assessed using approximate tests based on Fishers Z transformation (alpha = 0.05). In individuals with DM, first metatarsal sagittal plane excursion during gait was negatively associated with pressure time integral under the medial forefoot (r = -0.42 and -0.06, DM and Ctrl, P = 0.02). Similarly, lateral forefoot sagittal plane excursion during gait was negatively associated with pressure time integral under the lateral forefoot (r = -0.56 and -0.11, DM and Ctrl, P = 0.02). Frontal plane excursion of the calcaneus was negatively associated with medial (r = -0.57 and 0.12, DM and Ctrl, P < 0.01) and lateral (r = -0.51 and 0.13, DM and Ctrl, P < 0.01) heel and medial forefoot pressure time integral (r = -0.56 and -0.02, DM and Ctrl, P < 0.01). The key findings of our study indicate that reductions in segmental foot mobility were accompanied by increases in local loading in subjects with DM. Reduction in frontal plane calcaneal mobility during walking serves as an important functional marker of loss of foot flexibility in subjects with DM.

A New Device for Assessing Ankle Dorsiflexion Motion: Reliability and Validity

STUDY DESIGN Clinical measurement. OBJECTIVE To determine the validity and reliability of measures obtained using a custom-made device for assessing ankle dorsiflexion motion and stiffness. BACKGROUND Limited dorsiflexion has been implicated in the evolution of foot pain in a number of clinical populations. Assessment of ankle dorsiflexion range of motion (ROM) is, therefore, commonly performed as part of a foot and ankle examination. Conventional goniometric assessment methods have demonstrated limited intertester reliability, while alternative methods of measurements are generally more difficult to use. The Iowa ankle range of motion (IAROM) device was designed in an attempt to develop a simple, clinically relevant, and time- and cost-effective tool to measure ankle dorsiflexion range of motion and stiffness. METHODS Validity and intertester reliability of dorsiflexion range-of-motion measures using the IAROM device were assessed at 10, 15, 20, and 25 Nm of passively applied dorsiflexion torque, with both the knee extended and flexed approximately 20°. Stiffness (change in torque/change in dorsiflexion angle) values were determined using the angular change obtained between the 15- and 25-Nm torque levels. Convergent validity (n = 12) was assessed through comparison of ankle dorsiflexion angles measured simultaneously with the IAROM device and an optoelectronic motion analysis system. Intertester reliability (n = 17) was assessed by 2 testers who took measurements within the same day. RESULTS Validity testing demonstrated excellent agreement (intraclass correlation coefficient [ICC] values ranging from 0.95 to 0.98). Reliability testing demonstrated good to excellent intertester agreement (ICC values ranging from 0.90 to 0.95). The ICCs for ankle joint dorsiflexion stiffness were .71 and .85 for the knee in an extended and flexed position, respectively. CONCLUSION The IAROM device provides valid and reliable measurement of ankle dorsiflexion ROM. The IAROM device also allows calculation of stiffness by measuring ROM at multiple torque levels, although the reliability of the measurement is not optimal.

Increased Passive Ankle Stiffness and Reduced Dorsiflexion Range of Motion in Individuals With Diabetes Mellitus

Background: The purpose of our study was to compare ankle range of motion and stiffness in individuals with and without diabetes mellitus using a reliable and valid technique and to document the effect of knee flexion and severity of pathology on ankle range of motion and stiffness. Methods: Twenty-five individuals with diabetes mellitus and 64 nondiabetic individuals, similar in age and gender profile, participated in this study. Results: Results revealed that individuals with diabetes mellitus had both significantly lower peak dorsiflexion range of motion (5.1 and 11.5 degrees, p < 0.001) and higher passive ankle stiffness (0.016 and 0.008 Nm/kg/degree, p < 0.01) than non-diabetic individuals. In individuals with diabetes mellitus, a positive relationship between glycemic control and duration of diabetes mellitus and ankle stiffness ((r 2 = 0.48 and 0.24 respectively, p < 0.01 for both) was found. Conclusion: While decreased range of motion and increased stiffness in the diabetes mellitus population seem clinically intuitive, as far as we know this is the first study to confirm the concurrent existence of both these findings in the plantarflexors in individuals with diabetes mellitus. We applied a reliable and valid technique, one that allowed control of confounding factors such as knee flexion position and differences in determination of end range of motion, and documented a mean 41% loss in dorsiflexion excursion. Changes in the muscle, stemming from underlying pathology, are hypothesized to account for a significant part of the lost range of motion. Changes in ankle range of motion and stiffness may have important implications in plantar loading and ulcer formation.

Shoe Inserts Alter Plantar Loading and Function in Patients With Midfoot Arthritis

STUDY DESIGN Experimental laboratory study supplemented by a case series. OBJECTIVES (1) To assess the effect of a 4-week intervention with a full-length insert on functional outcomes in patients with midfoot arthritis; (2) to examine the effect of the custom molded three-quarter-length (3Q) and full-length (FL) carbon graphite insert on plantar loading in patients with midfoot arthritis. BACKGROUND Given the coexistence of pain and lower-arched foot alignment in patients with midfoot arthritis, arch-restoring orthotic devices such as the 3Q insert are frequently recommended. However, patients continue to report foot pain despite using the 3Q insert. The FL insert has been proposed as an alternative, but objective data examining its efficacy are lacking. METHODS Twenty female patients with midfoot arthritis participated in the study. Functional outcomes were assessed using the Foot Function Index-Revised (FFI-R). Plantar loading during walking was measured in the following conditions: shoe only, shoe with 3Q insert, and shoe with FL insert. Repeated-measures analyses of variance with post hoc analyses were used for statistical analysis. RESULTS FL insert use for 4 weeks resulted in a 12% improvement in total FFI-R score (mean +/- SD before, 35.6 +/- 10.9; after, 31.1 +/- 9.8 [P = .03]). FL insert use resulted in a 20% reduction in medial midfoot average pressure loading (mean +/- SD, 64.8 +/- 20.4 and 51.0 +/- 15.4 kPa, with 3Q and FL insert respectively [P = .015]) and an 8.5% reduction in medial midfoot contact time (mean +/- SD, 84.9% +/- 6.4% and 76.4% +/- 7.1% of stance, with 3Q and FL insert respectively [P<.01]), compared to the 3Q insert. No differences in plantar loading were discerned between the shoe-only and FL conditions. CONCLUSION Symptomatic improvement in patients with midfoot arthritis treated with a FL insert was accompanied by reduced magnitude and duration of loading under the medial midfoot. These preliminary outcomes suggest that the FL insert may be a viable alternative in the conservative management of patients with midfoot arthritis. LEVEL OF EVIDENCE Therapy, level 4. J Orthop Sports Phys Ther 2009;39(7):522-531. doi:10.2519/jospt.2009.2900.

The effect of foot structure on 1st metatarsophalangeal joint flexibility and hallucal loading.

The purpose of our study was to examine 1st metatarsophalangeal (MTP) joint motion and flexibility and plantar loads in individuals with high, normal and low arch foot structures. Asymptomatic individuals (n=61), with high, normal and low arches participated in this study. Foot structure was quantified using malleolar valgus index (MVI) and arch height index (AHI). First MTP joint flexibility was measured using a specially constructed jig. Peak pressure under the hallux, 1st and 2nd metatarsals during walking was assessed using a pedobarograph. A one-way ANOVA with Bonferroni-adjusted post hoc comparisons was used to assess between-group differences in MVI, AHI, early and late 1st MTP joint flexibility in sitting and standing, peak dorsiflexion (DF), and peak pressure under the hallux, 1st and 2nd metatarsals. Stepwise linear regression was used to identify predictors of hallucal loading. Significant between-group differences were found in MVI (F(2,56)=15.4, p<0.01), 1st MTP late flexibility in sitting (F(2,57)=3.7, p=0.03), and standing (F(2,57)=3.7, p=0.03). Post hoc comparisons demonstrated that 1st MTP late flexibility in sitting was significantly higher in individuals with low arch compared to high arch structure, and that 1st MTP late flexibility in standing was significantly higher in individuals with low arch compared to normal arch structure. Stepwise regression analysis indicated that MVI and 1st MTP joint early flexibility in sitting explain about 20% of the variance in hallucal peak pressure. Our results provide objective evidence indicating that individuals with low arches show increased 1st MTP joint late flexibility compared to individuals with normal arch structure, and that hindfoot alignment and 1st MTP joint flexibility affect hallucal loading.

Comparison of in vivo segmental foot motion during walking and step descent in patients with midfoot arthritis and matched asymptomatic control subjects

The purpose of this study was to compare in vivo segmental foot motion during walking and step descent in patients with midfoot arthritis and asymptomatic control subjects. Segmental foot motion during walking and step descent was assessed using a multi-segment foot model in 30 patients with midfoot arthritis and 20 age, gender and BMI matched controls. Peak and total range of motion (ROM), referenced to subtalar neutral, were examined for each of the following dependent variables: 1st metatarso-phalangeal (MTP1) dorsiflexion, 1st metatarsal (MT1) plantarflexion, ankle dorsiflexion, calcaneal eversion and forefoot abduction. The results showed that, compared to level walking, step descent required greater MTP1 dorsiflexion (p<0.01), MPT1 plantarflexion (p<0.01), ankle dorsiflexion (p<0.01), calcaneus eversion (p=0.03) and forefoot abduction (p=0.01), in all subjects. In addition, step descent also necessitated greater MTP1 dorsiflexion (p<0.01), ankle dorsiflexion (p<0.01) and forefoot abduction (p=0.02) excursion compared to walking. Patients with midfoot arthritis responded differently to the step task compared to control subjects in terms of MT1 and calcaneus eversion excursion. During walking, patients with midfoot arthritis showed significantly less MT1 plantarflexion excursion compared to control subjects (p=0.03). However, during step descent, both groups showed similar MT1 plantarflexion excursion. During walking, patients with midfoot arthritis showed similar calcaneus eversion excursion compared to control subjects. However, during step descent, patients with midfoot arthritis showed significantly greater calcaneus eversion excursion compared to control subjects (p=0.03). Independently or in combination, these motions may contribute to articular stress and consequently to symptoms in patients with midfoot arthritis.

Regional plantar pressure during walking, stair ascent and descent

Regional plantar pressures during stair walking may be injurious in at risk populations. However, limited data are available examining the reliability of plantar pressure data collected during stair walking. The aims of this study were three fold; to assess the reliability of the plantar pressure data recorded during stair walking, to assess the effects of level ground and stair walking on plantar loading, and to develop regression equations to predict regional plantar pressures in stair walking from those collected on level ground. Fifteen subjects without conditions affecting their ability to walk on level surfaces or stairs were recruited. Each participant performed at least 10 steps in level ground and stair walking while plantar pressure data were recorded in six foot regions. Reliability was assessed using Intraclass Correlation Coefficient. A repeated measures ANOVA was used to assess the effect of activity on plantar pressure, and a linear regression was used to predict forefoot loading during stair walking. A reliability of 0.9 was achieved within 10 steps in all foot regions, with the forefoot requiring fewer steps. Plantar pressures were influenced by both, foot region and activity, with the heel and forefoot regions generally experiencing lower peak pressures and maximal forces during stair walking than level ground walking. The regression equations predicting peak pressure during stair walking accounted for between 37% and 70% of the variance of the stair walking data. These findings establish the reliability of plantar pressure data collected during stair walking. Future studies should investigate these parameters in clinical populations.

The effect of arch height on kinematic coupling during walking

The purpose of the current study was to assess kinematic coupling within the foot in individuals across a range of arch heights. Seventeen subjects participated in this study. Weight-bearing lateral radiographs were used to measure the arch height, defined as angle between the 1st metatarsal and the calcaneus. A kinematic model including the 1st metatarsal, lateral forefoot, calcaneus and tibia was used to assess foot kinematics during walking. Four coupling ratios were calculated: calcaneus frontal to forefoot transverse plane motion (Calcaneal EV/Forefoot AB), calcaneus frontal to transverse plane motion (Calcaneus EV/AB), forefoot sagittal to transverse plane motion (Forefoot DF/AB), and 1st metatarsal sagittal to transverse plane motion (1st Metatarsal DF/AB). Pearson product moment correlations were used to assess the relationship between arch height and coupling ratios. Mean (SD) radiographic arch angles of 129.8 (12.1) degrees with a range from 114 to 153 were noted, underscoring the range of arch heights in this cohort. Arch height explained approximately 3%, 38%, 12% and 1% of the variance in Calcaneal EV/Forefoot AB, Calcaneus EV/AB, Forefoot DF/AB and 1st Metatarsal DF/AB respectively. Calcaneal EV/Forefoot AB, Calcaneus EV/AB, Forefoot DF/AB and 1st Metatarsal DF/AB coupling ratios of 1.84 ± 0.80, 0.56 ± 0.35, 0.96 ± 0.27 and 0.43 ± 0.21 were noted, consistent with the twisted foot plate model, windlass mechanism and midtarsal locking mechanisms. Arch height had a small and modest relationship with kinematic coupling ratios during walking.

Nonmedicinal therapy in the management of ankle arthritis

Purpose of reviewThe incidence of ankle osteoarthritis has increased in recent years, in part, secondary to vehicular trauma. This review describes conservative and operative intervention strategies along with current research related to the management of ankle osteoarthritis. Recent findingsSelf-reported physical function in patients with ankle osteoarthritis is equivalent to or worse than that of patients with endstage kidney disease, congestive heart failure, or cervical-spine pain and radiculopathy. Nonoperative-intervention strategies such as assistive devices, orthoses, and viscosupplements are frequently used in this clinical population. However, limited objective data are available examining outcomes following nonoperative intervention. Ankle fusion serves as a standard-surgical treatment for end-stage ankle osteoarthritis. The limitations of ankle fusion include prolonged immobilization, a relatively high risk of nonunion, and adjacent joint arthritis. Increasing evidence supports the safety and efficacy of total-ankle arthroplasty (TAA). Current (third generation) TAA prostheses feature cementless design and ligament preservation with reduced bone resection and improved instrumentation. SummaryLimited objective evidence exists to guide clinical decision-making related to nonoperative choices such as assistive devices, orthoses, and viscosupplements. Outcomes from prospective clinical trials indicate that newer total ankle-arthroplasty designs provide substantial pain relief in patients with end-stage ankle osteoarthritis.

Midfoot arthritis: Nonoperative Options and Decision Making for Fusion

Arthritis of the midtarsal and tarsometatarsal joints (midfoot) has emerged as a challenging problem because of its high potential for chronic foot pain and functional disability. Although the incidence of patients presenting with midfoot arthritis is increasing at an alarming rate, guidelines for clinical decision making are lacking in the literature. The primary aim of treatment is to afford pain relief by enhancing midfoot stability and modifying loads sustained at the inflamed joints. These treatment goals are attempted initially through conservative management such as orthoses followed by surgery. This manuscript discusses strategies for conservative management and details the operative techniques for tarsometatarsal fusion. In addition, outcomes after intervention are presented.