Foot and ankle joint kinematics in rheumatoid arthritis cannot only be explained by alteration in walking speed

Interacting effects of AFO stiffness, neutral angle and footplate stiffness on gait in case of plantarflexor weakness: A predictive simulation study

To maximize effects of dorsal leaf ankle foot orthoses (AFOs) on gait in people with bilateral plantarflexor weakness, the AFO properties should be matched to the individual. However, how AFO properties interact regarding their effect on gait function is unknown. We studied the interaction of AFO bending stiffness with neutral angle and footplate stiffness on the effect of bending stiffness on walking energy cost, gait kinematics and kinetics in people with plantarflexor weakness by employing predictive simulations. Our simulation framework consisted of a planar 11 degrees of freedom model, containing 11 muscles activated by a reflex-based neuromuscular controller. The controller was optimized by a comprehensive cost function, predominantly minimizing walking energy cost. The AFO bending and footplate stiffness were modelled as torsional springs around the ankle and metatarsal joint. The neutral angle of the AFO was defined as the angle in the sagittal plane at which the moment of the ankle torsional spring was zero. Simulations without AFO and with AFO for 9 bending stiffnesses (0-14 Nm/degree), 3 neutral angles (0-3-6 degrees dorsiflexion) and 3 footplate stiffnesses (0-0.5-2.0 Nm/degree) were performed. When changing neutral angle towards dorsiflexion, a higher AFO bending stiffness minimized energy cost of walking and normalized joint kinematics and kinetics. Footplate stiffness mainly affected MTP joint kinematics and kinetics, while no systematic and only marginal effects on energy cost were found. In conclusion, the interaction of the AFO bending stiffness and neutral angle in bilateral plantarflexor weakness, suggests that these should both be considered together when matching AFO properties to the individual patient.

Gait characteristics and functional outcomes during early follow-up are comparable in patients with calcaneal fractures treated by either the sinus tarsi or the extended lateral approach

BACKGROUND

To overcome the substantial functional loss after calcaneal fractures (CF), surgical treatment currently consists of two strategies, namely the commonly used extended lateral approach (ELA) and the less invasive sinus tarsi approach (STA). Despite the comparable anatomical restoration, the biomechanical and functional outcome of these strategies during early rehabilitation has not yet been investigated.

RESEARCH QUESTION

To evaluate changes in gait characteristics and functional development in patients with CF treated by either STA or ELA.

METHODS

A total of 56 patients with unilateral CF were included in this retrospective study. 26 patients were treated by ELA while 30 patients underwent surgery through the STA. Functional and biomechanical measurements were performed at follow-up periods of three and six months. Foot and ankle kinetics and kinematics were extracted using instrumented gait analysis with a multi segment foot model. Physical and mental components of the Short Form 36 (SF-36) and total scoring of the AOFAS hindfoot scale were used for functional evaluation. Statistical analysis was performed using Mann Whitney and Student's t-test. Effect sizes of group differences were calculated using Cohen's d.

RESULTS

Comparisons between ELA and STA showed no significant difference regarding the biomechanical and functional outcome. Within-group comparisons showed significant (p < 0.05) improvements from three to six month follow-up. Ankle joint and hindfoot kinematics showed increased mobility during walking of up to 34% and 26%, respectively. Maximum ankle joint moment also improved by up to 34% while vertical ground reaction force increased by 8%. Functional outcome only revealed significant changes in the physical component of SF-36.

SIGNIFICANCE

ELA and STA treatments revealed comparable functional improvements in patients with unilateral intraarticular calcaneal fractures during early rehabilitation. The less invasive STA provides adequate restoration of dynamic foot function and could serve as a viable alternative to the commonly used ELA.

Association between arthritis score at the onset of the disease and long-term locomotor outcome in adjuvant-induced arthritis in rats

INTRODUCTION

To investigate the connection between the intensity of initial symptoms of inflammation and locomotor outcome in rheumatoid arthritis, we examined the relationship between long-term locomotor abnormalities and signs of inflammation at the onset of the disease in adjuvant-induced arthritis (AIA) in rats.

METHODS

The arthritis score and hind-paw diameter were followed from immunization to day 195 (~7 months). At this time, locomotion was recorded during forced treadmill walking using 3D motion technology before radiographic scoring of hind limb joint damage. Many locomotor parameters were analyzed including time and length parameters, limbs kinematics, lateral paw position at toe off, maximal hind-paw elevation and posture. Ankle mobility was assessed from range of motion (ROM) of the joint during locomotion. Experiments were run in AIA (n = 18) and age-matched non-AIA rats (n = 8).

RESULTS

All AIA rats exhibited signs of inflammation at day 14 with a peak of inflammatory symptoms at day 22 post-immunization. After the first episode of inflammation, 83 % of AIA rats demonstrated recurrent disease (from week 6 to week 23). The frequency of inflammatory episodes (1 to 5) was not linked to the arthritis score at day 22. At day 195 post-immunization, AIA rats showed significantly impaired locomotion and radiographic lesions as compared to control rats. Significant relationships were observed between most locomotion-related parameters and concurrent ROM of ankle, which correlated negatively with the radiographic score. ROM of ankle at day 195 correlated negatively with both the arthritis score and hind-paw diameter measured at day 14, 22 and 30 post-immunization.

CONCLUSION

Decreased ankle mobility can be considered a driver of locomotion impairment in AIA. In this model, the severity of the initial inflammatory symptoms had a good prognostic value for long-term locomotor outcome.

Gait characteristics associated with the foot and ankle in inflammatory arthritis: a systematic review and meta-analysis

BACKGROUND

Gait analysis is increasingly being used to characterise dysfunction of the lower limb and foot in people with inflammatory arthritis (IA). The aim of the systematic review was to evaluate the spatiotemporal, foot and ankle kinematic, kinetic, peak plantar pressure and muscle activity parameters between patients with inflammatory arthritis and healthy controls.

METHODS

An electronic literature search was performed on Medline, CINAHL, SportsDiscus and The Cochrane Library. Methodological quality was assessed using a modified Quality Index. Effect sizes with 95% confidence intervals (CI) were calculated as the standardised mean difference (SMD). Meta-analysis was conducted if studies were homogenous.

RESULTS

Thirty six studies with quality ranging from high to low met the inclusion criteria. The majority of studies reported gait parameters in Rheumatoid arthritis (RA). The gait pattern in RA was characterised by decreased walking speed (SMD 95% CI -1.57, -2.25 to -0.89), decreased cadence (SMD -0.97, -1.49 to -0.45), decreased stride length (SMD -1.66, -1.84 to -1.49), decreased ankle power (SMD -1.36, -1.70 to -1.02), increased double limb support time (SMD 1.03, 0.84 to 1.22), and peak plantar pressures at the forefoot (SMD 1.11, 0.76 to 1.45). Walking velocity was reduced in psoriatic arthritis and gout with no differences in ankylosing spondylitis. No studies have been conducted in polymyalgia rheumatica, systemic sclerosis or systemic lupus erythematosus.

CONCLUSIONS

The review identified the majority of studies reporting gait adaptations in RA, but limited evidence relating to other IA conditions. Poor data reporting, small sample sizes and heterogeneity across IA conditions limit the interpretation of the findings. Future studies may consider a standardised analytical approach to gait analysis that will provide clinicians and researchers with objective evidence of foot function in people with IA.

Reduced locomotor activity correlates with increased severity of arthritis in a mouse model of antibody-induced arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by synovial hyperplasia and progressive cartilage and bone destruction that leads to a substantial loss of general functions and/or a decline in physical activities such as walking speed in humans. The K/BxN serum transfer arthritis in mice shares many immunological and pathological features with human RA. Very few studies are available in mice that investigate the changes in physical activity in relation to arthritis development. In this study we investigate the effect of arthritis on the locomotor activity of mice during K/BxN sera transfer arthritis.

METHODS

Arthritis was induced in Balb/c mice by injecting intraperitoneally with 200ul of K/BxN sera; Balb/c mice injected with phosphate buffered saline (PBS) served as control. Progress of arthritis was estimated by daily measurements of joint thickness. Each mouse's locomotor activity (travel distance and travel time) was assessed every day for duration of 20 minute period using the SmartCage™ platform. Data were analyzed using the SmartCage™ analysis software (CageScore™).

RESULTS

Arthritic Balb/c mice showed a reduction in distance covered and travel speed when compared to arthritis-free, control Balb/c mice. Maximum decline in locomotor activity was observed during the peak period of the disease and correlated to the increase in joint thickness in the arthritic mice.

CONCLUSION

This report demonstrates that measuring locomotor activity of mice during progression of K/BxN sera-induced arthritis using the SmartCage™ platform offers a quantitative method to assess physical activity in mice during arthritis.

Quantifying gait deviations in individuals with rheumatoid arthritis using the Gait Deviation Index

OBJECTIVES

In this study we evaluated the usability of the Gait Deviation Index (GDI), an index that summarizes the amount of deviation in movement from a standard norm, in adults with rheumatoid arthritis (RA). The aims of the study were to evaluate the ability of the GDI to identify gait deviations, assess inter-trial repeatability, and examine the relationship between the GDI and walking speed, physical disability, and pain.

METHOD

Sixty-three adults with RA and 59 adults with typical gait patterns were included in this retrospective case-control study. Following a three-dimensional gait analysis (3DGA), representative gait cycles were selected and GDI scores calculated. To evaluate the effect of walking speed, GDI scores were calculated using both a free-speed and a speed-matched reference set. Physical disability was assessed using the Health Assessment Questionnaire (HAQ) and subjects rated their pain during walking.

RESULTS

Adults with RA had significantly increased gait deviations compared to healthy individuals, as shown by lower GDI scores [87.9 (SD = 8.7) vs. 99.4 (SD = 8.3), p < 0.001]. This difference was also seen when adjusting for walking speed [91.7 (SD = 9.0) vs. 99.9 (SD = 8.6), p < 0.001]. It was estimated that a change of ≥ 5 GDI units was required to account for natural variation in gait. There was no evident relationship between GDI and low/high RA-related physical disability and pain.

CONCLUSIONS

The GDI seems to useful for identifying and summarizing gait deviations in individuals with RA. Thus, we consider that the GDI provides an overall measure of gait deviation that may reflect lower extremity pathology and may help clinicians to understand the impact of RA on gait dynamics.

Gait deviations in individuals with inflammatory joint diseases and osteoarthritis and the usage of three-dimensional gait analysis

This chapter describes three-dimensional gait analysis and common gait deviations in adults with rheumatoid arthritis (RA) and osteoarthritis (OA). Furthermore, we describe changes in gait deviations following surgical and non-surgical interventions. Gait analysis is used to define gait deviations and to evaluate varying surgical approaches, types of surgeries and non-pharmacologic interventions. Most studies examine gait in adults with knee OA. Limitations of existing studies include small samples, poor selection of controls, sample heterogenecity, lack of baseline gait assessments and inconsistency in measurement. Across studies, time and distance parameters are generally used to provide a global measure of gait deviations. Individuals with RA and OA in the lower extremities exhibit reduced walking speed/cadence and decreased motion and moments in relation to healthy subjects. Future research should include larger sample sizes, the use of proper controls, pre- and post-assessments and identify gait abnormalities early in the disease process to minimise long-term consequences.

Kinematic coupling relationships exist between non-adjacent segments of the foot and ankle of healthy subjects

Pathologies of foot and ankle structures affect the kinematics at the site of the impaired structure but also influence kinematics elsewhere in the foot and ankle. An understanding of kinematic coupling relationships in the foot could provide insight into mechanisms that explain differences in foot and ankle kinematics between healthy and pathological subjects. The aim of this study was to explore foot and ankle kinematic coupling relationships between adjacent and non-adjacent segments of healthy subjects and evaluate individual variability of and effect of walking speed on these relationships. Gait of 14 subjects was recorded at comfortable and two slower walking speeds to assess individual foot kinematics during stance phase. A qualitative evaluation of the coupling relationships was made using angle-angle plots to determine their consistency, i.e. changes in movement direction of each segment occurred at the same time and the plot returned along the same line after the turning point. The Pearson correlation coefficient of determination (R(2)) was used to provide a quantitative evaluation of coupling. Individual variability was assessed with the coefficient of variation (CV). The Friedman-test was used to test the effect of walking speed. Consistent coupling relationships were observed between hindfoot in/eversion and hallux plantar/dorsiflexion (R(2) 0.7, CV 0.2), between hindfoot in/eversion and forefoot ab/adduction (R(2) 0.5, CV 0.3) and between leg rotation and midfoot collapse/elevation (R(2) 0.5, CV 0.4). Less or non-consistent coupling relationships were observed between the other studied segments. Walking speed significantly influenced coupling relationships between hindfoot and midfoot.