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Objective: The objective of this study was to examine the effects of diabetes mellitus and peripheral neuropathy (DMPN), limited joint mobility, and weight-bearing on foot and ankle sagittal movements and characterize the foot and ankle position during heel rise., Methods: Sixty people with DMPN and 22 controls participated. Primary outcomes were foot (forefoot on hindfoot) and ankle (hindfoot on shank) plantar-flexion/dorsiflexion angle during 3 tasks: unilateral heel rise, bilateral heel rise, and non-weight-bearing ankle plantar flexion. A repeated-measures analysis of variance and Fisher exact test were used., Results: Main effects of task and group were significant, but not the interaction in both foot and ankle plantar flexion. Foot and ankle plantar flexion were less in people with DMPN compared with controls in all tasks. Both DMPN and control groups had significantly less foot and ankle plantar flexion with greater weight-bearing; however, the linear trend across tasks was similar between groups. The DMPN group had a greater percentage of individuals in foot and/or ankle dorsiflexion at peak unilateral heel rise compared with controls, but the foot and ankle position was similar at peak bilateral heel rise between DMPN and control groups., Conclusion: Foot and ankle plantar flexion is less in people with DMPN. Less plantar flexion in non-weight-bearing suggests that people with DMPN have limited joint mobility. However, peak unilateral and bilateral heel rise is less than the available plantar flexion range of motion measured in non-weight-bearing, indicating that limited joint mobility does not limit heel rise performance. A higher frequency of people with DMPN are in foot and ankle dorsiflexion at peak unilateral heel rise compared with controls, but the position improved with lower weight-bearing., Impact: Proper resistance should be considered with physical therapist interventions utilizing heel rise because foot and ankle plantar flexion position could be improved by reducing the amount of weight-bearing., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Physical Therapy Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: A toe-extension movement pattern may contribute to metatarsophalangeal joint deformity and ulceration in people with diabetes. We sought to quantify the relationship between toe extension magnitude and variability during three functional tasks (ankle range of motion, sit to stand, walking) with metatarsophalangeal joint deformity, and identify potential mechanisms associated with a toe-extension movement pattern., Methods: Individuals with diabetes and peripheral neuropathy were included (n = 60). Metatarsophalangeal joint deformity was assessed using computed tomography (CT). Toe-extension movement was quantified using 3-dimensional motion capture. Linear regression was used to investigate the role of toe-extension movement pattern on metatarsophalangeal joint deformity. Regression analysis was used to identify mechanisms (neuropathy severity, foot intrinsic muscle deterioration ratio, ankle dorsiflexion range of motion) contributing to toe-extension movement pattern., Findings: Toe extension with each functional task as well as the mean and coefficient of variation across all tasks were significantly related to metatarsophalangeal joint deformity (range of correlation coefficients = (-0.386, 0.692), p ≤ 0.001). Ankle dorsiflexion range of motion was associated with mean toe extension across all tasks (r sp  = -0.282, p = 0.029). Neuropathy severity and foot intrinsic muscle deterioration ratio were associated with toe extension variability (r sp  = -0.373, p = 0.003 and r sp  = -0.266, p = 0.043; respectively)., Interpretation: Greater magnitude and lower variability of a toe-extension movement pattern was found to be associated with metatarsophalangeal joint deformity. These findings may support clinical assessment and treatment of movement across more than one task., (Copyright © 2021. Published by Elsevier Ltd.)

Background: Limited joint mobility at the shoulder is an understudied problem in people with diabetes mellitus. The purpose of this study was to determine the differences in shoulder kinematics between a group with diabetes and those without diabetes., Methods: Fifty-two participants were recruited, 26 with diabetes and 26 non-diabetes controls (matched for age, BMI and sex). Three-dimensional position of the trunk, scapula and humerus were collected using electromagnetic tracking sensors during scapular plane elevation and rotation movements., Findings: Glenohumeral external rotation was reduced by 11.1°-16.3° (P<0.05) throughout the humerothoracic elevation range of motion, from neutral to peak elevation, in individuals with diabetes as compared to controls. Peak humerothoracic elevation was decreased by 10-14°, and peak external rotation with the arm abducted was decreased 22° in the diabetes group compared to controls (P<0.05). Scapulothoracic and glenohumeral internal rotation motions were not different between the two groups., Interpretation: Shoulder limited joint mobility, in particular decreased external rotation, was seen in individuals with diabetes as compared to control participants. Future research should investigate causes of diabetic limited joint mobility and strategies to improve shoulder mobility and prevent additional detrimental changes in movement and function., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A new method for measuring bone mineral density (BMD) of the tarsal and metatarsals is described using volumetric quantitative computed tomography (VQCT) in subjects with diabetes mellitus and peripheral neuropathy. VQCT images of a single foot were acquired twice from eight subjects (mean age 51 [11 SD], seven males, one female). The cortical shells of the seven tarsal and five metatarsal bones were identified and semiautomatically segmented from adjacent bones. Volume and BMD of each bone were measured separately from the two acquired scans for each subject. Whole-bone semiautomatic segmentation measurement errors were determined as the root mean square coefficient of variation for the volume and BMD of 0.8% and 0.9%, respectively. In addition to the whole-bone segmentation methods, we performed atlas-based partitioning of subregions within the second metatarsal for all subjects, from which the volumes and BMDs were obtained for each subregion. The subregion measurement BMD errors (root mean square coefficient of variation) within the shaft, proximal end, and distal end were shown to vary by approximately 1% between the two scans of each subject. The new methods demonstrated large variations in BMDs between the 12 bones of the foot within a subject and between subjects, and between subregions within the second metatarsal. These methods can provide an important outcome measure for clinical research trials investigating the effects of interventions, aging, or disease progression on bone loss, or gain, in individual foot bones.

Background and Purpose: The primary purpose of this study was to report differences in calf intermuscular adipose tissue (IMAT), muscle strength (peak torque), power, and physical function in individuals with obesity, diabetes mellitus (DM), and peripheral neuropathy (PN) compared with those without these impairments. A secondary purpose was to assess the relationship between IMAT and muscle strength, power, and physical function., Subjects and Methods: Six participants with obesity, DM, and PN (2 women, 4 men; mean age=58 years, SD=10; mean body mass index=36.3, SD=5; mean modified Physical Performance Test [PPT] score=22, SD=3) and 6 age- and sex-matched control subjects without these impairments were assessed and compared in muscle strength, muscle power, physical functioning, and muscle and fat volume, including IMAT in the calf muscles. Muscle, adipose tissue, and IMAT volumes of each calf were quantified by noninvasive magnetic resonance imaging. Muscle strength and power of the plantar-flexor and dorsiflexor muscles were quantified using isokinetic dynamometry. The modified PPT was used to assess physical function., Results: Leg muscle and fat volumes were similar between groups, although IMAT volumes were 2.2-fold higher in the subjects with obesity, DM, and PN (X=120 cm(3), SD=47) than in the control subjects (X=54 cm(3), SD=41). Muscle strength, muscle power, ratio of leg muscle power to leg muscle volume, and modified PPT scores were lower in subjects with obesity, DM, and PN compared with the control subjects., Discussion and Conclusion: The data indicate that excess fat infiltration in leg skeletal muscles is associated with low calf muscle strength, low calf muscle power, and impaired physical function in individuals who are obese with DM and PN.

Background: Standard prevention and treatment strategies to decrease peak plantar pressure include a total contact insert with a metatarsal pad, but no clear guidelines exist to determine optimal placement of the pad with respect to the metatarsal head. The purpose of this study was to determine the effect of metatarsal pad location on peak plantar pressure in subjects with diabetes mellitus and peripheral neuropathy., Methods: Twenty subjects with diabetes mellitus, peripheral neuropathy, and a history of forefoot plantar ulcers were studied (12 men and eight women, mean age=57+/-9 years). CT determined the position of the metatarsal pad relative to metatarsal head and peak plantar pressures were measured on subjects in three footwear conditions: extra-depth shoes and a 1) total contact insert, 2) total contact insert and a proximal metatarsal pad, and 3) total contact insert and a distal metatarsal pad. The change in peak plantar pressure between shoe conditions was plotted and compared to metatarsal pad position relative to the second metatarsal head., Results: Compared to the total contact insert, all metatarsal pad placements between 6.1 mm to 10.6 mm proximal to the metatarsal head line resulted in a pressure reduction (average reduction=32+/-16%). Metatarsal pad placements between 1.8 mm distal and 6.1 mm proximal and between 10.6 mm proximal and 16.8 mm proximal to the metatarsal head line resulted in variable peak plantar pressure reduction (average reduction=16+/-21%). Peak plantar pressure increased when the metatarsal pad was located more than 1.8 mm distal to the metatarsal head line., Conclusions: Consistent peak plantar pressure reduction occurred when the metatarsal pad in this study was located between 6 to 11 mm proximal to the metatarsal head line. Pressure reduction lessened as the metatarsal pad moved outside of this range and actually increased if the pad was located too distal of this range. Computational models are needed to help predict optimal location of metatarsal pad with a variety of sizes, shapes, and material properties.

Objectives: To compare the amount of weight-bearing activity and estimates of cumulative plantar tissue stress between subjects with and without diabetes mellitus and a history of recurrent plantar ulcers., Design: Cross-sectional study with matched groups., Background: Weight-bearing activity among individuals with diabetes is likely to influence the amount of mechanical trauma accumulated by plantar tissues, yet activity levels have not been accounted for in previous measurements of plantar tissue stress or predictions of plantar tissue injury., Methods: Study groups included subjects with diabetes mellitus and peripheral neuropathy, either with or without a history of recurrent plantar ulcers, and non-diabetic control subjects (n=10 per group). Pressure on the plantar foot was assessed as subjects walked at their preferred speed in the shoes they reported wearing most often each day. Physical activity was monitored over seven consecutive days using an accelerometer. The product of mean daily strides and forefoot pressure-time integral was used to estimate daily cumulative stress on the plantar forefoot., Results: Subjects with diabetes and a history of recurrent plantar ulcers were 46% less active than subjects without diabetes (mean (SD)=2727 (1345) versus 5037 (2624) strides/day, P=0.04), and accumulated 41% less daily stress on the forefoot than non-diabetic and diabetic control subjects without a history of plantar ulcers (mean (SD)= 210 (134) versus 354 (118) and 354 (148) MPas/day respectively, P=0.03)., Conclusions: Subjects with diabetes and a history a previous ulcers may be susceptible to plantar tissue injury even at relatively low levels of cumulative tissue stress., Relevance: Changes in weight-bearing activity following plantar tissue injury in patients with diabetes may influence plantar tissue adaptation and the risk of ulcer recurrence.

Various foot structures are thought to influence forefoot plantar pressures during walking. High peak plantar pressures (PPP) during walking in people with diabetes mellitus (DM) and peripheral neuropathy (PN) can cause skin breakdown. The question addressed by this study is "What are the primary forefoot structural factors that predict regional PPP during walking in groups of people with and without DM and PN?" Twenty people with DM and PN (mean age 55+/-9 years, 6 female, 14 male, BMI=33+/-8) and 20 people without DM, matched for gender, age, and BMI were tested. Measures of foot structure were taken from three-dimensional images constructed from spiral X-ray computed tomography. Peak plantar pressure data were recorded during walking. Hierarchical multiple regression analysis was used to predict regional PPP at the great toe and five metatarsal heads from selected structural and walking variables. Metatarsal phalangeal joint angle (hammer toe deformity) was the most important variable predicting pressure, accounting for 19-45% of the PPP variance at five of the six locations in the DM group. Soft tissue thickness, hallux valgus, and forefoot arthropathy were the most important predictors of PPP in the control group. Combinations of structural and walking variables accounted for 47-71% of the variance in the DM group and 52-83% of the variance of PPP during walking in the control group. These structural variables, especially hammer toe deformity, should be considered in attempts to develop strategies to reduce excessive forefoot PPP that may contribute to skin breakdown or other injury.

High plantar pressures contribute to skin breakdown in patients with diabetes mellitus and peripheral neuropathy. The primary purpose of this study was to determine the point during the stance phase of walking that corresponds with forefoot peak plantar pressures. Results indicate that peak plantar pressures occurred at 80% +/- 5% of the stance phase of gait in subjects with diabetes and transmetatarsal amputation, as well as in control subjects. Improved methods of footwear design or walking strategies proposed to patients should focus on the demands of the foot during the late stance phase of walking in order to increase available weightbearing area or to decrease forces, which will minimize plantar pressures and reduce trauma to the neuropathic foot.

Background and Purpose: Reports in the surgical and rehabilitation literature suggest that patients with transmetatarsal amputations (TMAs) function well with regular shoes and a toe filler. Functional limitations, however, have not been documented in this population. The purpose of this study was to compare the function of patients with diabetes mellitus (DM) and TMA with that of age- and gender-matched control subjects., Subjects: Thirty subjects (15 subjects with DM and TMAs and 15 control subjects), with a mean age of 62.3 years (SD = 9.2, range = 43-83), were studied., Methods: Function was measured using the Functional Reach Test (FRT), the Physical Performance Test (PPT), walking speed for 15.2 m (50 ft), and the Sickness Impact Profile (SIP). Subjects in the TMA-DM group wore standard shoes with a toe filler., Results: The TMA-DM group scored lower (mean +/- standard deviation) than did the control group on all tests (FRT: 19.1 +/- 8.6 vs 31.5 +/- 9.1 cm [7.5 +/- 3.4 vs 12.4 +/- 3.6 in]; PPT: 18.7 +/- 4.8 vs 24.1 +/- 2.2 points [28 points possible]; walking speed: 51.5 +/- 13.2 vs 75.6 +/- 9.3 m/min; SIP: 17.0 +/- 12.7 vs 3.7 +/- 4.7)., Conclusion and Discussion: Persons with DM and TMAs have considerable functional limitations. Research is needed to determine whether therapeutic footwear or other forms of rehabilitation can improve their function.

Objective: Patients with diabetes mellitus (DM) and a transmetatarsal amputation (TMA) have considerable deficits in function compared with age-matched controls. The purpose of this study was to determine if therapeutic footwear could improve the functional mobility of patients with DM and TMA., Study Design: Repeated-measures design., Setting: Academic medical center., Patients: Thirty subjects (10 women, 20 men) with DM and a TMA, with a mean age of 61.7 +/- 4.0 yrs., Interventions: Six types of footwear evaluating the following components: length of shoe (full-length or short shoe), a rigid rocker-bottom sole, and an ankle-foot-orthosis., Outcome Measures: Physical Performance Test (PPT), functional reach, and walking speed. Measurements in each footwear condition occurred after a 1-month adjustment period., Results: Patients wearing full-length custom-made shoes with a total-contact insert, a rigid rocker-bottom sole or a short shoe with a rigid rocker-bottom sole (with or without an ankle-foot-orthosis) had similar and significantly higher scores in the PPT and faster walking speed than when wearing regular shoes with a toe filler (p < .05). The short shoe and the ankle-foot-orthosis, however, generated many patient complaints about cosmesis and restriction at the ankle, respectively. There were no differences in any of the measures of functional reach., Conclusion: Although there are individual exceptions, we recommend the full-length shoe, total-contact insert, and a rigid rocker-bottom sole for most patients with DM and a TMA.

Background and Purpose: Limited ankle plantar-flexor moments and power during walking have been documented in several patient populations and are believed to contribute to gait deviations. The primary purpose of this study was to determine the relationship of plantar-flexor peak torque (PFPT) and dorsiflexion range of motion (ROM) to peak ankle moments and power during walking in a group of subjects without diabetes mellitus (DM) and in a group of subjects with DM and associated peripheral neuropathies., Subjects: Nineteen subjects, 9 with DM and associated peripheral neuropathies (mean age = 58 years, SD = 14, range = 35-75 years) and 10 without DM (mean age = 57 years, SD = 11, range = 37-68 years), were evaluated., Methods: The following data were collected on all subjects: PFPT, dorsiflexion ROM, and ankle moments and power during walking (using a two-dimensional link-segment model). Hierarchical multiple regression was used for data analysis., Results: Plantar-flexor peak torque made substantial contributions to the ankle moment (40%) and ankle plantar-flexor power (53%) during walking. There also was a high correlation between PFPT and dorsiflexion ROM (r = .78) and between dorsiflexion ROM and ankle power (r = .72)., Conclusion and Discussion: Plantar-flexor peak torque and dorsiflexion ROM are interrelated and appear to be important factors that contribute to ankle plantar-flexor moments and power during walking. This finding suggests that increasing PFPT and dorsiflexion ROM may help decrease gait deviations such as decreased step length and walking speed. When increasing PFPT is not possible, the natural occurrence of limited dorsiflexion ROM may help to maximize ankle moments during walking. Further research is needed to test whether these proposed treatment strategies can have a clinically useful effect. [Mueller MJ, Minor SD, Schaaf JA, et al. Relationship of plantar-flexor peak torque and dorsiflexion range of motion to kinetic variables during walking.

Background and Purpose: Patients with diabetes and peripheral neuropathy have a high incidence of injuries while walking. Biomechanical analysis of their walking may lead to treatments to reduce these injuries. The purpose of this study was to compare (1) the gait characteristics, (2) the plantar-flexor peak torques, and (3) the ankle range of motion of subjects with diabetes mellitus (DM) and peripheral neuropathy with those of age-matched controls., Subjects: Twenty subjects, 10 with DM and a history of peripheral neuropathy (DM group) (mean age = 58 years, SD = 15, range = 35-75) and 10 subjects without diabetes (NODM group) (mean age = 57 years, SD = 11, range = 37-68), were evaluated., Methods: The following data were collected on all subjects: ankle joint mobility, plantar-flexor peak torque (ankle strength), kinematics of the trunk and lower extremity during normal walking, and ground reaction forces. Moments and power at the ankle, knee, and hip during walking were calculated using a two-dimensional link-segment model., Results: The DM group subjects showed less ankle mobility, ankle moment, ankle power, velocity, and stride length during walking than the NODM group subjects. A significant decrease in ankle strength and mobility appeared to be the primary factor contributing to the altered walking patterns of the DM group., Conclusion and Discussion: The DM group subjects appeared to pull their legs forward using hip flexor muscles (hip strategy) rather than pushing the legs forward using plantar-flexor muscles (ankle strategy), as seen in the NODM group subjects. Implications for treatment are presented to attempt to reduce the number of injuries during walking in patients with DM and peripheral neuropathy.