Subungual exostosis is a slow-growing, benign outgrowth of normal bone under the nail that affects the nail unit. The most common location in the foot is the dorsal surface of the distal phalanx of the big toe. Clinically, it can appear in combination with a variety of nail disorders, masking the underlying bone condition, which is frequently unrecognized or misdiagnosed. A new classification system for these lesions is proposed on the basis of the clinical signs and symptoms present during examination and the associated disorders of the nail plate. Also, a therapeutic algorithm that describes surgical approaches to the different presentations of this disorder is presented. (J Am Podiatr Med Assoc 99(6): 519–524, 2009)
Inclusion cysts are benign lesions that appear as a consequence of traumatic inclusion of epidermal cells into the dermis. They can be painful if they appear under pressure areas, especially the metatarsal heads. We report a case of a 36-year-old woman with an intractable plantar keratosis lesion under the third metatarsal head of 3 years’ duration. Ultrasonography revealed the presence of a subcutaneous mass with a growing epidermoid. It was surgically excised, and pathology confirmed the diagnosis of a plantar epidermoid cyst. All symptoms disappeared after the excision of the lesion. This case should alert the clinician about the existence of keratotic lesions in the metatarsal heads commonly diagnosed and treated as intractable plantar keratosis, although they are not directly derived from metatarsal overload. Some of the lesions could be directly derived from skin problems aggravated by pressure from the metatarsal head. This should be taken into consideration when addressing the management of these lesions. (J Am Podiatr Med Assoc 99(2): 148–152, 2009)
Background: We evaluated normal plantar pressures and studied the effect of weight, cadence, and age on forefoot plantar pressures in healthy subjects by using the Biofoot (Instituto de Biomecánica de Valencia, Valencia, Spain) in-shoe measurement system.
Methods: The feet of 45 healthy subjects with no evident foot or lower-limb diseases were measured with the Biofoot in-shoe system. The forefoot was divided into seven areas: the first through fifth metatarsal heads, the hallux, and the second through fifth lesser toes. Three trials of 8 sec each were recorded twice in each subject, and the mean was used to analyze peak and mean plantar pressures. A multiple regression model including weight, age, and cadence was run for each metatarsal head, the hallux, and the lesser toes. Intraclass correlation coefficients and coefficients of variation were also calculated to assess reliability.
Results: The second metatarsal head had the greatest peak (960 kPa) and mean (585.1 kPa) pressures, followed by the third metatarsal head. Weight and cadence combined explained 18% and 23% of peak plantar pressure at the second and third metatarsal heads, respectively (P < .001). The intraclass correlation coefficient varied from 0.76 to 0.96 for all variables. The coefficient of variation between sessions ranged from 5.8% to 9.0%.
Conclusion: The highest peak and mean plantar pressures were found at the second and third metatarsal heads in healthy subjects. Weight, cadence, and age explained a low variability of this pressure pattern. The Biofoot in-shoe system has good reliability to measure plantar pressures. These data will have implications for the understanding of normal foot biomechanics and its determinants. (J Am Podiatr Med Assoc 98(4): 302–310, 2008)
Background: Research on foot orthoses has shown that their effect on the kinematics of the rearfoot is variable, with no consistent patterns of changes being demonstrated. It has also been hypothesized that the mechanical effect of foot orthoses could be subject specific. The purpose of our study was to determine if maximally pronated feet have a different response to frontal plane wedging of foot orthoses than do nonmaximally pronated feet during static stance.
Methods: One hundred six feet of 53 healthy asymptomatic subjects were divided into two groups (maximally pronated and nonmaximally pronated) on the basis of their subtalar joint rotational position during relaxed bipedal stance. Functional foot orthoses were constructed for each subject and the relaxed calcaneal stance position was measured while standing on five separate frontal plane orthosis wedging conditions, 10° valgus, 5° valgus, no wedging, 5° varus, and 10° varus, to assess changes in calcaneal position.
Results: Relative to the no-wedging condition, there were statistically significant differences (P < .05) in calcaneal position between the maximally pronated and the nonmaximally pronated feet with the 10° valgus and the 10° varus wedging conditions. No significant differences in calcaneal position were found with the 5° varus and the 5° valgus wedging conditions.
Conclusions: Our study shows that the response to foot orthoses is variable between individuals. Maximally pronated subjects do not exhibit the same response to frontal plane wedging of foot orthoses as do nonmaximally pronated with 10° wedging. Intrinsic biomechanical factors such as subtalar joint position may influence the response to foot orthoses. (J Am Podiatr Med Assoc 99(1): 13–19, 2009)
This article reports on a case of sensorimotor neuropathy in a 55-year-old man that developed after vincristine therapy. Subsequent biopsy of the sural nerve and electromyographic studies revealed the presence of Charcot-Marie-Tooth disease. Only 17 patients who developed severe neuropathy with very low accumulated doses of vincristine have been described in the literature. Pain and lateral ankle instability were treated with a functional orthosis. Orthopedic treatment and the biomechanical basis of foot and ankle problems in patients with vincristine therapy–induced Charcot-Marie-Tooth disease are discussed. (J Am Podiatr Med Assoc 93(3): 229-233, 2003)
Comparison of dynamic stiffness of foot joints was previously proposed to investigate pathologic situations with changes in the properties of muscle and passive structures. Samples must be controlled to reduce the variability within groups being compared, which may arise from different sources, such as gait speed or Foot Posture Index (FPI).
Variability in the measurement of the dynamic stiffness of ankle, midtarsal, and metatarsophalangeal joints was studied in a controlled sample of healthy men with normal FPI, and the effect of gait speed was analyzed. In experiment 1, dynamic stiffnesses were obtained in three sessions, five trials per session, for each participant, taking the mean value across trials as representative of each session. In experiment 2, five trials were considered at slow, comfortable, and fast velocities.
Similar intersession and intrasession errors and intraparticipant errors within sessions were found, indicating the goodness of using five trials per session for averaging. The intraparticipant and interparticipant variability data provided can be used to select the sample size in future comparative analyses. Significant differences with gait speed were observed in most dynamic stiffnesses considered, with a general rise when gait speed increased, especially at the midtarsal joint, this being attributed to an active modulation produced by the central nervous system.
Differences with gait speed were higher than intrasession and intersession repeatability errors for the propulsion phases at the ankle and midtarsal joints; comparative analyses at these phases need more exhaustive control of gait speed to reduce the required sample size.
Background: Dynamic stiffness can be used for studying foot pathologic abnormalities and for developing prostheses and orthoses. Although previous works have studied the role of ankle joint stiffness during gait, other foot joints have not yet been analyzed. We sought to characterize the dynamic stiffness of the ankle, midtarsal, and metatarsophalangeal joints during normal walking.
Methods: Kinematics and contact data from four healthy individuals during walking were registered with a three-dimensional motion analysis system and a pressure platform. Stance phases with flexion moment-angle linear relationships were identified, and dynamic stiffnesses were calculated from the slope of their linear regressions. Intraparticipant repeatability was analyzed using analyses of variance, and interparticipant variability was checked through the SD of averaged participant stiffnesses.
Results: Flexion moment-angle linear relationships were identified (R2 > 0.98) during the early and late midstance phases and the propulsion phase at the ankle (2.76, 5.23, and 3.42 N·m/kg/rad, respectively) and midtarsal (15.88, 3.90, and 4.64 N·m/kg/rad, respectively) joints. At the metatarsophalangeal joint, a linear relationship (R2 > 0.96) occurred only during the propulsion phase (0.11 N·m/kg/rad). High dynamic stiffness variability was observed during the late and early midstance phases at the ankle and midtarsal joints, respectively.
Conclusions: These results may serve as a basis for future studies aimed at investigating the role of dynamic stiffness identified herein in different foot disorders. The importance of properly controlling the samples in such studies is highlighted. Study of the dynamic stiffnesses identified might be used in the design of prostheses, orthoses, and other assistive devices.
Background: The scientific evidence behind the mechanical function of foot orthoses is still controversial. Research studies that have investigated the kinematic effect of foot orthoses on the lower extremity have shown variable results, with orthoses causing either no significant change or a small significant change in foot kinematics.
Methods: The right limbs of 12 healthy asymptomatic individuals were studied in three walking conditions: barefoot, with a 7° rearfoot varus wedge, and with a 7° rearfoot valgus wedge. Kinematic and kinetic variables measured were the foot progression angle, the peak internal tibial rotation angle, and net ankle inversion moments during the stance phase in the three conditions.
Results: There were statistically significant differences in the foot progression angle between the barefoot and varus wedge conditions and between the varus and valgus wedge conditions. There were no significant changes in peak internal tibial rotation among the three conditions tested. However, rearfoot varus wedges significantly reduced net ankle inversion moments compared with barefoot and rearfoot valgus wedges.
Conclusions: These results support the idea that foot orthoses work by methods other than by changing kinematic parameters. The present study supports the concept that foot orthoses work primarily by altering kinetics, with their effects on kinematics being secondary. (J Am Podiatr Med Assoc 99(5): 415–421, 2009)
Background: We sought to investigate the thickness of plantar fascia, measured by means of ultrasonographic evaluation in healthy, asymptomatic subjects, and its relationship to body mass index, ankle joint dorsiflexion range of motion, and foot pronation in static stance.
Methods: One hundred two feet of 51 healthy volunteers were examined. Sonographic evaluation with a 10-MHz linear array transducer was performed 1 and 2 cm distal to its insertion. Physical examination was also performed to assess body mass index, ankle joint dorsiflexion, and degree of foot pronation in static stance. Both examinations were performed in a blinded manner.
Results: Body mass index showed moderate correlation with plantar fascia thickness at the 1- and 2-cm locations. Ankle dorsiflexion range of motion showed no correlation at either location. Foot pronation showed an inverse correlation with plantar fascia thickness at the 2-cm location and no correlation at the 1-cm location.
Conclusion: Body mass index and foot supination at the subtalar joint are related to increased thickness at the plantar fascia in healthy, asymptomatic subjects. Although the changes in thickness were small compared with those in patients with symptomatic plantar fasciitis, they could play a role in the mechanical properties of plantar fascia and in the development of plantar fasciitis. (J Am Podiatr Med Assoc 98(5): 379–385, 2008)