Neuropathic pain associated with first metatarsophalangeal joint osteoarthritis: frequency and associated factors.

OBJECTIVE: To determine whether neuropathic pain is a feature of first metatarsophalangeal (MTP) joint osteoarthritis (OA). METHODS: Ninety-eight participants (mean age 57.4 years, standard deviation 10.3) with symptomatic radiographic first MTP joint OA completed the painDETECT questionnaire (PDQ), which incorporates nine questions regarding the intensity and quality of pain. The likelihood of neuropathic pain was determined using established cut-points of the PDQ. Participants with unlikely neuropathic pain were then compared to those with possible/likely neuropathic pain in relation to age, sex, general health (Short Form [SF] 12), psychological wellbeing (Depression, Anxiety and Stress Scale), pain characteristics (self-efficacy, duration, and severity), foot health (Foot Health Status Questionnaire [FHSQ]), first MTP dorsiflexion range of motion and radiographic severity. Effect sizes (Cohen's d) were also calculated. RESULTS: Thirty (31%) participants had possible/likely neuropathic pain (possible n=19, [19.4%], likely n=11 [11.2%]). The most common neuropathic symptoms were sensitivity to pressure (56%), sudden pain attacks/electric shocks (36%) and burning (25%). Compared to those with unlikely neuropathic pain, those with possible/likely neuropathic pain were significantly older (d=0.59, p=0.010), had worse SF12 physical (d=1.10, p<0.001), pain self-efficacy (d=0.98, p<0.001), FHSQ pain (d=0.98, p<0.001) and FHSQ function (d=0.82, p<0.001) scores, and had higher pain severity at rest (d=1.01, p<0.001). CONCLUSION: A significant proportion of individuals with first MTP joint OA report symptoms suggestive of neuropathic pain, which may partly explain the suboptimal responses to commonly used treatments for this condition. Screening for neuropathic pain may assist in the selection of targeted interventions and improve clinical outcomes

Special theme article : science and sociology of footwear

Journal editorial

Shoe-stiffening inserts for first metatarsophalangeal joint osteoarthritis (the SIMPLE trial): study protocol for a randomised controlled trial

BACKGROUND: This article describes the design of a parallel-group, participant- and assessor-blinded randomised controlled trial comparing the effectiveness of shoe-stiffening inserts versus sham shoe insert(s) for reducing pain associated with first metatarsophalangeal joint (MTPJ) osteoarthritis (OA). METHODS: Ninety participants with first MTPJ OA will be randomised to receive full-length shoe-stiffening insert(s) (Carbon Fibre Spring Plate, Paris Orthotics, Vancouver, BC, Canada) plus rehabilitation therapy or sham shoe insert(s) plus rehabilitation therapy. Outcome measures will be obtained at baseline, 4, 12, 24 and 52 weeks; the primary endpoint for assessing effectiveness being 12 weeks. The primary outcome measure will be the foot pain domain of the Foot Health Status Questionnaire (FHSQ). Secondary outcome measures will include the function domain of the FHSQ, severity of first MTPJ pain (using a 100-mm Visual Analogue Scale), global change in symptoms (using a 15-point Likert scale), health status (using the Short-Form-12® Version 2.0 and EuroQol (EQ-5D-5L™) questionnaires), use of rescue medication and co-interventions, self-reported adverse events and physical activity levels (using the Incidental and Planned Activity Questionnaire). Data will be analysed using the intention-to-treat principle. Economic analysis (cost-effectiveness and cost-utility) will also be performed. In addition, the kinematic effects of the interventions will be examined at 1 week using a three-dimensional motion analysis system and multisegment foot model. DISCUSSION: This study will determine whether shoe-stiffening inserts are a cost-effective intervention for relieving pain associated with first MTPJ OA. The biomechanical analysis will provide useful insights into the mechanism of action of the shoe-stiffening inserts. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry, identifier: ACTRN12616000552482 . Registered on 28 April 2016

Are clinical measures of foot posture and mobility associated with foot kinematics when walking?

Background: There is uncertainty as to which foot posture measures are the most valid in terms of predicting kinematics of the foot. The aim of this study was to investigate the associations of clinical measures of static foot posture and mobility with foot kinematics during barefoot walking. Method: Foot posture and mobility were measured in 97 healthy adults (46 males, 51 females; mean age 24.4 ± 6.2 years). Foot posture was assessed using the 6-item Foot Posture Index (FPI), Arch Index (AI), Normalised Navicular Height (NNHt) and Normalised Dorsal Arch Height (DAH). Foot mobility was evaluated using the Foot Mobility Magnitude (FMM) measure. Following this, a five-segment foot model was used to measure tri-planar motion of the rearfoot, midfoot, medial forefoot, lateral forefoot and hallux. Peak and range of motion variables during load acceptance and midstance/propulsion phases of gait were extracted for all relative segment to segment motion calculations. Hierarchical regression analyses were conducted, adjusting for potential confounding variables. Results: The degree of variance in peak and range of motion kinematic variables that was independently explained by foot posture measures was as follows: FPI 5 to 22 %, NNHt 6 to 20 %, AI 7 to 13 %, DAH 6 to 8 %, and FMM 8 %. The FPI was retained as a significant predictor across the most number of kinematic variables. However, the amount of variance explained by the FPI for individual kinematic variables did not exceed other measures. Overall, static foot posture measures were more strongly associated with kinematic variables than foot mobility measures and explained more variation in peak variables compared to range of motion variables. Conclusions: Foot posture measures can explain only a small amount of variation in foot kinematics. Static foot posture measures, and in particular the FPI, were more strongly associated with foot kinematics compared with foot mobility measures. These findings suggest that foot kinematics cannot be accurately inferred from clinical observations of foot posture alone

Movement of the human foot in 100 pain free individuals aged 18–45 : implications for understanding normal foot function

Background: Understanding motion in the normal healthy foot is a prerequisite for understanding the effects of pathology and thereafter setting targets for interventions. Quality foot kinematic data from healthy feet will also assist the development of high quality and research based clinical models of foot biomechanics. To address gaps in the current literature we aimed to describe 3D foot kinematics using a 5 segment foot model in a population of 100 pain free individuals. Methods: Kinematics of the leg, calcaneus, midfoot, medial and lateral forefoot and hallux were measured in 100 self reported healthy and pain free individuals during walking. Descriptive statistics were used to characterise foot movements. Contributions from different foot segments to the total motion in each plane were also derived to explore functional roles of different parts of the foot. Results: Foot segments demonstrated greatest motion in the sagittal plane, but large ranges of movement in all planes. All foot segments demonstrated movement throughout gait, though least motion was observed between the midfoot and calcaneus. There was inconsistent evidence of movement coupling between joints. There were clear differences in motion data compared to foot segment models reported in the literature. Conclusions: The data reveal the foot is a multiarticular structure, movements are complex, show incomplete evidence of coupling, and vary person to person. The data provide a useful reference data set against which future experimental data can be compared and may provide the basis for conceptual models of foot function based on data rather than anecdotal observations