High-arched Feet Research Articles

Effect of Running Shoe Type on the Distribution and Magnitude of Plantar Pressures in Individuals with Low- or High-Arched Feet

Research addressing the effect of running shoe type on the low- or high-arched foot during gait is limited. We sought 1) to analyze mean plantar pressure and mean contact area differences between low- and high-arched feet across three test conditions, 2) to determine which regions of the foot (rearfoot, midfoot, and forefoot) contributed to potential differences in mean plantar pressure and mean contact area, and 3) to determine the association between the static arch height index and the dynamic modified arch index. Plantar pressure distributions for 75 participants (40 low arched and 35 high arched) were analyzed across three conditions (nonshod, motion control running shoes, and cushioning running shoes) during treadmill walking. In the motion control and cushioning shoe conditions, mean plantar contact area increased in the midfoot (28% for low arched and 68% for high arched), whereas mean plantar pressure decreased by approximately 30% relative to the nonshod condition. There was moderate to good negative correlation between the arch height index and the modified arch index. Cushioning and motion control running shoes tend to increase midfoot mean plantar contact area while decreasing mean plantar pressure across the low- or high-arched foot.

The Prevalence of Four Common Pathomechanical Foot Deformities in Primary School Students in Taichung County

Background/Purpose. To investigate the overall prevalence of four common pathomechanical foot deformities, including flexible flatfoot, high-arch foot, hindfoot valgus and hallux valgus in primary school students in Taichung County and to determine the prevalence of these foot deformities in boys and girls in different primary school grades. Methods. We enrolled 18, 006 students (8883 boys and 9123 girls) from 14 primary schools in Taichung County. The arch index, hallux valgus angle, and hindfoot valgus angle in all students were obtained by footprint analysis. Grade-and sex-specific prevalence rates were calculated for each foot deformity. Using correspondence analysis, we constructed a mapping-based relationship between foot deformities, age, and sex. Results. The overall prevalence rates were 13.88% for flexible flatfoot, 1.32% for high-arch foot, 3.33% for hindfoot valgus and 1.40% for hallux valgus. Descriptive analysis indicated that flexible flatfoot was more common among boys in all grades and that high-arch foot was more common among girls in grades 5 and 6. We identified age as the primary predictive factor for all of the common foot deformities. Flexible flatfoot and hindfoot valgus were more frequent in boys and young girls. Hallux valgus was most common among older girls. Conclusion. This is the first study to determine the prevalence of flexible flatfoot, high-arch foot, hindfoot valgus and hallux valgus in a Chinese population. We found a strong association between flexible flatfoot and hindfoot valgus. Primary-school students with common pathomechanical foot deformities should be followed up on a regular basis to reduce the prevalence of foot deformity-related musculoskeletal problems.

Foot posture influences the electromyographic activity of selected lower limb muscles during gait

BackgroundSome studies have found that flat-arched foot posture is related to altered lower limb muscle function compared to normal- or high-arched feet. However, the results from these studies were based on highly selected populations such as those with rheumatoid arthritis. Therefore, the objective of this study was to compare lower limb muscle function of normal and flat-arched feet in people without pain or disease.MethodsSixty adults aged 18 to 47 years were recruited to this study. Of these, 30 had normal-arched feet (15 male and 15 female) and 30 had flat-arched feet (15 male and 15 female). Foot posture was classified using two clinical measurements (the arch index and navicular height) and four skeletal alignment measurements from weightbearing foot x-rays. Intramuscular fine-wire electrodes were inserted into tibialis posterior and peroneus longus under ultrasound guidance, and surface EMG activity was recorded from tibialis anterior and medial gastrocnemius while participants walked barefoot at their self-selected comfortable walking speed. Time of peak amplitude, peak and root mean square (RMS) amplitude were assessed from stance phase EMG data. Independent samples t-tests were performed to assess for significant differences between the normal- and flat-arched foot posture groups.ResultsDuring contact phase, the flat-arched group exhibited increased activity of tibialis anterior (peak amplitude; 65 versus 46% of maximum voluntary isometric contraction) and decreased activity of peroneus longus (peak amplitude; 24 versus 37% of maximum voluntary isometric contraction). During midstance/propulsion, the flat-arched group exhibited increased activity of tibialis posterior (peak amplitude; 86 versus 60% of maximum voluntary isometric contraction) and decreased activity of peroneus longus (RMS amplitude; 25 versus 39% of maximum voluntary isometric contraction). Effect sizes for these significant findings ranged from 0.48 to 1.3, representing moderate to large differences in muscle activity between normal-arched and flat-arched feet.ConclusionDifferences in muscle activity in people with flat-arched feet may reflect neuromuscular compensation to reduce overload of the medial longitudinal arch. Further research is required to determine whether these differences in muscle function are associated with injury.

Poster 159: Running Shoe Selection Among Adolescent Cross-Country Runners

Objective: To determine what factors are most important to adolescent cross-country runners in selecting and replacing running shoes, and to assess whether these factors are consistent with current footwear recommendations in the literature. Design: Cross-sectional, descriptive survey. Setting: 4 community high schools. Participants: 223 cross-country runners, grades 7 through 12 (52% males, 48% females). Interventions: Not applicable. Main Outcome Measures: Descriptive analysis of factors important in running shoe selection, including assessment of knowledge of arch type and appropriate running shoe selection, and knowledge of recommended mileage before replacing running shoes. Results: 73% of survey participants identified arch type compatibility with shoe design as the most important factor in choosing a running shoe. However, only 57% reported knowing their arch type. When asked to match a specific arch type with its recommended correlative running shoe design, only 17%, 16%, and 31% correctly matched footwear recommended for a flat foot, high arch, or neutral foot respectively. 60% of respondents answered incorrectly for all 3 arch types. 82% reported not knowing mileage recommendations (500 miles or less) for running shoe replacement. Conclusions: A majority of adolescent runners in our study identified arch type and shoe design as the most important factors in choosing a running shoe. Our study demonstrated a significant lack of knowledge in this population with respect to appropriate selection and replacement of running shoes. As this knowledge deficit represents a modifiable injury risk factor, adolescent cross-country runners would benefit from further targeted education on footwear considerations for injury prevention.

Pressure characteristics in painful pes cavus feet resulting from Charcot–Marie–Tooth disease

Charcot–Marie–Tooth (CMT) disease often presents with peripheral muscle imbalance associated with a painful cavus (medial high-arched) foot deformity which becomes increasingly severe and rigid as the disease progresses. The purpose of this study was to investigate the effect of pes cavus on foot pain and dynamic plantar pressure in CMT, and to explore the relationships between plantar pressure and pain. Sixteen participants diagnosed with CMT and painful pes cavus were assessed for foot posture, ankle dorsiflexion range of motion, levels of foot pain, functional impairment, health-related quality of life and plantar pressure distribution while walking. Plantar pressure parameters (mean pressure, peak pressure, pressure–time integral) and contact duration were measured using the Novel Pedar ® in-shoe capacitance transducer system and the foot was divided into rearfoot, midfoot and forefoot regions for analysis. Increasing cavus foot deformity was associated with more widespread foot pain and increased pressure under the forefoot and midfoot regions. In contrast, peak pressure decreased under the rearfoot. Neither relationship was found between foot pain intensity and any of the pressure variables, nor was ankle dorsiflexion range of motion correlated with pain location, intensity or degree of pes cavus. Although pes cavus in CMT is associated with substantial pain and dysfunction, there is no clear link between foot pain and plantar pressure. The more severe the degree of pes cavus, however, the more pressure develops under the lateral margin of the foot; probably as a result of the changed foot–ground contact seen during gait.

The relationship between the height of the medial longitudinal arch (MLA) and the ankle and knee injuries in professional runners

Background Usually the rate of lower extremity's injuries in sports such as running is known to be correlated with the height of foot arches. Foot pressure measurement studies have shown controversial results in this issue, mainly due to the complexity of the foot structure. This study aimed to investigate if any relationship exists between the MLA height and the ankle/knee injuries in professional runners. It was also aimed to find out any association between the foot pressure patterns and the clinical navicular drop test in the subjects. Materials and methods Forty-seven professional runners were participated in this study and using the clinical navicular drop test, they were categorized into normal, low and high arch foot subjects. Using an Emed pedography platform (Novel, Germany), the maximum force, peak pressure and the contact area of their feet were studied in both static (single limb support) and dynamic conditions. Results The results of this study showed no strong correlation between the height of MLA and the rate of the ankle/knee injuries ( P = 0.58). The correlation between the clinical navicular drop test and the modified arch index (MAI) was between 0.32 in static and 0.57 in dynamic tests. Conclusion The results of this study conveyed that having a lower or higher than a normal MLA is not a definite risk factor for sports-related injuries. This might be due to the complexity of the foot structure and its ability to accommodate with new situations routinely occurs in sport. Furthermore, although a high correlation was not found between the clinical navicular drop test and the foot pressure indices, due to the clinical entity of this test, the obtained association is relatively good. A significant correlation was found between the foot pressure distribution in single limb support (static) and the dynamic conditions, which provides an extrapolation of the results of this type static condition tests to the dynamic conditions.

Predicting Outcomes in the Orthotic Management of Painful, Idiopathic Pes Cavus

People who have extremely high arched feet are subject to substantial foot pain, despite a lack of obvious pathology. Customized foot orthoses improve pain and function and reduce foot pressure, but their specificity is unclear. This study sought to identify predictive variables for improvement and to determine whether changes in foot pressure were correlated to changes in pain and function. Retrospective analysis of data from a randomized controlled clinical trial. Clinical movement analysis laboratory, School of Physiotherapy, University of Sydney. Subjects with painful, idiopathic pes cavus. Sixty-six subjects received customized foot orthoses; sixty-seven subjects were allocated a sham intervention. Foot pressure data, location and intensity of pain, Foot Posture Index values, and anthropometric and quality of life variables. No relationship between change in foot pressure and change in symptoms was found in either group. No individual characteristics were linked to improvement. Subjects who improved most had substantial pain, lowest function scores, and lowest scores for quality of life variables at entry. There was a possible link, in the orthosis group, between improvement and pain confined to the rear-foot region. The mechanisms by which orthotic intervention is effective in improving pain and function in painful, idiopathic pes cavus remain unclear and equivocal. A strong placebo effect may be in place, or perhaps relatively small changes in foot pressure, even those brought about by a flexible insole with limited shock-absorbing properties, is enough to achieve a clinically meaningful change in symptoms.

Impact of Ankle-Foot Orthoses on Static Foot Alignment in Children with Cerebral Palsy

Children with cerebral palsy who are able to walk are often managed with an ankle-foot orthosis to assist with walking. Previous studies have shown kinematic, kinetic, and energetic benefits during gait with the addition of an ankle-foot orthosis, although the mechanism of this gait improvement is unknown. The ability of orthoses to correct foot malalignment in children with cerebral palsy is not known. The current study was performed to determine the impact of orthoses on static foot alignment in children with cerebral palsy. A retrospective radiographic review was performed for 160 feet (102 patients). All patients had a diagnosis of cerebral palsy. Standing anteroposterior and lateral radiographs of the foot and ankle were made with the patient barefoot and while wearing the prescribed orthosis and were compared with use of the technique of quantitative segmental analysis of foot and ankle alignment. Analysis of the foot and ankle radiographs made with the patient barefoot and while wearing the brace revealed significant changes in all measurements of segmental alignment (p < 0.05). The magnitudes of these differences were small (<6 degrees or <10%) and would be considered clinically unimportant. The coupled malalignment of equinoplanovalgus (clinical flatfoot) showed radiographic correction of at least one segment (hindfoot, midfoot, or forefoot) to within the normal range in 24% to 44% of the feet. The coupled malalignment of equinocavovarus (clinical high arched foot) showed correction of at least one segment to within the normal range in 5% to 20% of feet. The present study demonstrates that the use of the ankle-foot orthoses failed to improve the static foot alignment in the majority of feet in children with cerebral palsy who were able to walk. Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.

Are in-shoe pressure characteristics in symptomatic idiopathic pes cavus related to the location of foot pain?

People who have extremely high arched feet may be subject to substantial levels of foot pain, despite the lack of obvious pathology. This study sought to investigate the effect of pes cavus on pain intensity and location and on the magnitude and distribution of foot pressure. Measurements were derived from the more symptomatic foot of 130 participants with painful, idiopathic pes cavus. Data were collected using Pedar ® in-shoe pressure sensors and averaged over nine randomly selected steps. Participant information, including location and intensity of pain, Foot Posture Index values and anthropometric and “quality of life” variables, were also recorded. Painful idiopathic pes cavus seems to provoke a more cautious gait pattern than normal, with reduced peak and mean pressure values, particularly in the fore- and rear-foot regions. In particular, participants with pain confined to the rear-foot exhibit an antalgic gait pattern, with lower pressure values and a longer period of foot-ground contact in the heel region than those with pain only in the fore-foot. We determined no clear predictors of pain in terms of foot posture or demographics, although people with high body mass index values are more likely to have pain in several regions. The relationship between the posture of the foot and the presentation of pain remains unclear, however we believe that the presence of heel pain in pes cavus may be more restricting than fore-foot pain.

Effective Orthotic Therapy for the Painful Cavus Foot

Patients with a cavus or high-arched foot frequently experience foot pain, which can lead to significant limitation in function. Custom foot orthoses are widely prescribed to treat cavus foot pain. However, no clear guidelines for their construction exist, and there is limited evidence of their efficacy. In a randomized, single-blind, sham-controlled trial, the effect of custom foot orthoses on foot pain, function, quality of life, and plantar pressure loading in people with a cavus foot type was investigated. One hundred fifty-four participants with chronic musculoskeletal foot pain and bilateral cavus feet were randomly assigned to a treatment group receiving custom foot orthoses (n = 75) or to a control group receiving simple sham insoles (n = 79). At 3 months, 99% of the participants provided follow-up data using the Foot Health Status Questionnaire. Foot pain scores improved more with custom foot orthoses than with the control (difference, 8.3 points; 95% confidence interval [CI], 1.2 to 15.3 points; P = .022). Function scores also improved more with custom foot orthoses than with the control (difference, 9.5 points; 95% CI, 2.9 to 16.1 points; P = .005). Quality-of-life data favored custom foot orthoses, although differences reached statistical significance only for physical functioning (difference, 7.0 points; 95% CI, 1.9 to 12.1 points; P = .008). Plantar pressure improved considerably more with custom foot orthoses than with the control for all regions of the foot (difference, -3.0 N . s/cm(2); 95% CI, -3.7 to -2.4 N . s/cm(2); P < .001). In conclusion, custom foot orthoses are more effective than a control for the treatment of cavus foot pain and its associated limitation in function.

The Evolution of Foot Morphology in Children Between 6 and 17 Years of Age: A Cross-Sectional Study Based on Footprints in a Mediterranean Population

Footprint evaluation is a widely used method for the determination of foot morphology, but its efficacy and validity are considered controversial. Dynamic footprints were obtained from both feet of 5,866 school-aged children (6-17 years old) to detect any foot changes during growth. The interpretation of the imprint was performed using a classification scheme consisting of 6 types of footprints. In this scheme, footprint types I and II represent the typical and intermediate high-arched foot, respectively. Types III and IV represent normal foot variants, while type V corresponds to the low-arched foot and type VI to the severe flat foot, the latter often encountered in pathological conditions. There was statistically significant difference (P<.05) in footprint-type frequencies between boys and girls of ages 7, 9, 11, 14, and 15, which probably indicates the difference in growth potential of the foot between sexes. The proportion of high- and low-arched foot types decreased with increasing age in both boys and girls. Even though critical changes of the foot are believed to occur during pre-school development, this study shows that considerable changes also take place during school age and until late adolescence.

Refined localization of dominant intermediate Charcot-Marie-Tooth neuropathy and exclusion of seven known candidate genes in the region.

Charcot-Marie-Tooth (CMT) neuropathy is one of the most common hereditary disorders of the human peripheral nervous system. The CMT syndrome includes weakness and atrophy of distal muscles, high arched feet (pes cavus), depressed or absent deep tendon reflexes, and mild sensory loss. Dominant intermediate CMT (DI-CMT) neuropathy is a form of CMT with intermediate median motor nerve conduction velocities. We previously localized the DI-CMT locus to a 16.8-cM region on chromosome 19p12-p13.2. Extended haplotype analysis and clinical assessment of additional family members and a report of a second family linked to this locus has enabled us to narrow the candidate region to a 6-cM interval flanked by D19S558 and D19S432. Selection of positional candidate genes for screening was performed on the basis of neural expression and microarray analysis of Schwann cell differentiation in vivo. Seven candidate genes have been investigated. These include six genes localized in the original linkage interval and one in the newly refined region. They are excluded as a cause for DI-CMT neuropathy.

Spinal Dysraphism: Trends in Northern India

Objective: To evaluate the clinical profiles, image findings and surgical outcome of 155 cases of spinal dysraphism. Methods: 155 patients were studied prospectively (143) or retrospectively (12). The male to female ratio was 1.5:1. Mean age at presentation was 5.7 years. Out of 155 cases of spinal dysraphism, 119 had open spina bifida [meningomyelocele (MMC) in 113 (72%), meningocele in 3 (2%) and myelocystocele in 3 (2%)] and 36 had occult spina bifida [split cord malformation (SCM) without overt MMC sac (pure SCM) in 29 (19%) and midline dermal sinus in 7 (4.5%)]. Lipomeningomyelocele constituted 73 of the 113 cases of MMC (65%). Twenty cases of MMC (18%) had associated SCM (complex spina bifida). The total number of cases with SCM was 49 (32%). Twenty-four children with MMC presented with an operative scar from previous surgery, performed at the periphery. After a detailed clinical evaluation of all patients, craniospinal MRI was the preferable mode of investigation. All patients underwent surgery and were clinically assessed over a mean follow-up period of 3.6 years. Results: MMC sac was the commonest skin manifestation seen in 89/155 cases (57%). Hypertrichosis and previous operative scar were noticed in 24 cases each (15%). Cutaneous hemangioma, skin tag and multiple neurofibroma were the other common superficial skin manifestations. Clinically, 103 patients (66.5%) had variable weakness of the lower limbs, and muscle atrophy was noticed in 56 cases (41%). Graded sensory loss, sphincteric dysfunction, trophic ulcer and backache were present in 89 (57%), 64 (36%), 17 (11%) and 9 cases (6%), respectively. Significant scoliosis in 56 cases (36%) and congenital talipes equinovarus in 51 cases (33%) were the most frequent neuroorthopedic deformities apart from high-arched foot, leg length discrepancy and flat foot. Common image findings were low-lying cord in 101 (65%), neural placode in 76/113 (49%), hydrosyrinx in 42 (27%), hydrocephalus in 71 (46%) and Chiari malformation in 62 cases (45%). The lumbosacral region in 56 cases (38%), followed by the lumbar region in 47 (30%), were the most common sites of occurrence of spina bifida. Of 71 hydrocephalic patients, 39 (55%) needed shunting before definitive surgery and 21 (30%) after the surgery. Eleven patients (15%) did not require shunting at all. CSF leak in 51 patients (33%), pseudomeningocele in 26 (17%), wound infection in 22 (14%) and meningitis in 13 (8%) were the most common postoperative complications. Two patients died in the postoperative period. During an average follow-up of 3.6 years (range 1.5–8 years), motor weakness improved in 47 children (45%) and remained static in 53 (52%), and 3 children showed deterioration in motor power. Sensory dysfunction improved in 43 (48%), remained static in 42 (47%) and deteriorated in 4 patients (4%). Sphincteric function clinically improved in 26 patients (41%) and was static in 38 (59%), and 6 patients (4%) had deterioration. Backache was dramatically relieved in all 9 patients with this complaint (100%). In 13 children with trophic ulcer (76%), it completely healed. Conclusion: A significant proportion of patients with open spinal dysraphism harbor an underlying SCM, an entity coined complex spina bifida (in our previous study). The incidence of hydrocephalus in spinal dysraphism is low in India in comparison to the Western world. Some patients with mild hydrocephalus on scan may not require a shunt operation. Surgical intervention should be early after entire neural axis screening by MRI.

Mapping of Charcot-Marie-Tooth Disease Type 1C to Chromosome 16p Identifies a Novel Locus for Demyelinating Neuropathies

Charcot-Marie-Tooth (CMT) neuropathy represents a genetically heterogeneous group of diseases affecting the peripheral nervous system. We report genetic mapping of the disease to chromosome 16p13.1-p12.3, in two families with autosomal dominant CMT type 1C (CMT1C). Affected individuals in these families manifest characteristic CMT symptoms, including high-arched feet, distal muscle weakness and atrophy, depressed deep-tendon reflexes, sensory impairment, slow nerve conduction velocities, and nerve demyelination. A maximal combined LOD score of 14.25 was obtained with marker D16S500. The combined haplotype analysis in these two families localizes the CMT1C gene within a 9-cM interval flanked by markers D16S519 and D16S764. The disease-linked haplotypes in these two pedigrees are not conserved, suggesting that the gene mutation underlying the disease in each family arose independently. The epithelial membrane protein 2 gene (EMP2), which maps to chromosome 16p13.2, was evaluated as a candidate gene for CMT1C.

Does arch height affect impact loading at the lower back level in running?

The purpose of this study was to evaluate the influence of the medial longitudinal arch height on the shock wave that repetitively reaches the lower back in running. Impact forces were measured simultaneously at the ground by a force plate and at the level of the low back, by means of an accelerometer, skin-mounted at the L3 spinal process. The medial longitudinal arch height was calculated as navicular height divided by foot length. Twelve healthy subjects ran barefoot and with an identical sport shoe at a constant speed. The sample size was divided equally into a low-arch and a high-arch group. Statistical analysis was performed by multivariate analysis of variance and Pearson's correlation. At low back level, there was a significantly lower acceleration amplitude and rate in the high-arch group (amplitude = mean, 1.74 g and SD, 0.94 g; rate = mean, 71.2 g/sec and SD, 58.0 g/sec) compared with the low-arch group (amplitude = mean 2.25 g and SD, 1.11 g; rate = mean, 111.5 g/sec and SD, 68.6 g/sec) (P < 0.001, each). At the ground, there was a slight negative correlation between arch height and initial loading rate in AP (-0.19; P < 0.01) and vertical (-0.22; P < 0.001) directions and a positive correlation between arch height and initial loading rate in the medial direction (0.22, P < 0.05). The results indicate that the high-arch foot is a better shock absorber with regard to the low back level than the low-arch foot.

Consistency of Visual Assessments of Arch Height among Clinicians

Flat feet and high-arched feet have been cited as risk factors for musculoskeletal injury and functional problems among runners and other active individuals, although there are no established quantitative definitions or measures for assessing either condition. As part of a larger study, four-plane photographs were made of the weight-bearing right foot of 246 young male Army trainees. These photographs were independently evaluated by six clinicians and rated on a scale of clearly flat-footed (category 1) to clearly high arched (category 5). There was much interclinician variability in the assessments, even for extremes of foot type. The probability of a clinician assessing a foot as clearly flat, given that another clinician had rated the foot as clearly flat, ranged from 0.32 to 0.79, with a median probability of 0.57, while for clearly high-arched feet, probabilities ranged from 0.0 to 1.00, with a median of 0.17. These findings demonstrate the need for objective standards and quantitative methods of evaluating foot morphology.

Foot morphologic characteristics and risk of exercise-related injury

It is widely accepted that persons with flat or high-arched feet are at increased risk of exercise-associated injury, even though this purported association has not been scientifically evaluated. We evaluate the risk of exercise-associated injury among young men with flat, normal, and high-arched feet. A prospective study of 246 US Army Infantry trainees followed up over a rigorous 12-week training program. All subjects were evaluated prior to onset of training. Evaluation included photographs of the right, weight-bearing foot that were digitized and utilized to make several measures of arch height. An army initial entry training center. All trainees beginning army training on 2 successive weeks were potential volunteers. There were no criteria for exclusion other than declining to participate (n = 3). The subjects were healthy, active young men with a mean age of 20.3 years. The occurrence of a lower-extremity musculoskeletal injury resulting in a visit to and a diagnosis by an army physician or physician assistant. Treating physicians and physician assistants were blind to participation status and were not study staff members. On univariate analysis, there was an association between arch height and risk of injury using several alternative operational definitions of foot type. The 20% with the flattest feet were at the lowest risk (reference group; odds ratio, 1.0), with adjusted odds ratios for any musculoskeletal injury of 3.0 (P < .05) for the middle 60% group and 6.1 (P < .05) for the highest 20% group. These findings do not support the hypothesis that low-arched individuals are at increased risk of injury, and they have implications for runners, exercise enthusiasts, and clinicians. It may be possible to prevent substantial morbidity among active populations by identifying individuals at high risk and advising alternate activities.

Variations in the Human Subtalar Joint

Clinical observations reveal that high-arched cavus feet are rigid while low-arched planus feet are hypermobile. One reason may be osseous variations in the human subtalar joint (STJ). This article reviews STJ anatomy, biomechanics, and pathomechanics and describes STJ variations found in 32 adult human calcanei. In the sample, 20 bones had two STJ facets and 12 bones had three STJ facets. A oneway Student t-test showed that the bones with two STJ facets had significantly greater (t = 2.23) facet surface area than the bones with three STJ facets. A second finding concerned three sagittal plane approximations of arch height and STJ axis angle. Calcanei with two STJ facets had significantly lower angles (tA = -1.99, tB = -1.82, and tC = -2.18) than three STJ facet calcanei. To the extent that osseous factors represent joint range of motion, this study shows that STJ facet number is a factor in foot mobility. J Orthop Sports Phy Ther 1987;8(10):489-494.

The Cavus Foot.

About one third of Dr. Subotnick's patients have high-arched feet. He describes the problems they encounter and how to treat them.

Clinical variability in congenital fiber type disproportion

Congenital Fiber Type Disproportion (CFTD) has recently been described as a consistent and stereotyped clinicopathological entity, including congenital non-progressive hypotonia and weakness, contractures, kyphoscoliosis, high arched palate, dislocated hips, short stature, and feet deformities. Our personal experience with this condition suggests a wider disparity in the physical appearance and associated abnormalities of affected individuals than the well-defined clinical syndrome previously described. We are presenting 5 cases, including 2 siblings, whose muscle biopsies satisfy the major histological and statistical criteria for the diagnosis. Although each child clearly had hypotonia and weakness consistent with a congenital myopathy, only 3 had a sufficient number of other similarities to establish the diagnosis clinically. The clinical spectrum of the other cases ranged from one infant whose only abnormality was mild hypotonia in the legs to another whose problems included severe motor impairment, marked mental retardation, growth failure, frontal bossing, abnormal hair, and scoliosis. Even in retrospect, the diagnosis of CFTD could not have been supported on clinical grounds alone. Therefore, CFTD is a congenital myopathy whose diagnosis can be made only by muscle biopsy, rather than a distinct syndrome whose diagnosis can be assumed on the basis of clinical characteristics alone.