Howard J. Hillstrom

The distributed plantar vertical force of neutrally aligned and pes planus feet

The distributed vertical ground reaction forces were determined for a normative population and contrasted with data from subjects with flat feet. Nineteen asymptomatic subjects, 11 with a neutrally aligned foot type (normal arch) and 8 with a pes planus foot type (low arch), were studied as they walked barefoot across a pressure plate. The pressure plate data were converted to force values at seven locations (subhallucal, five submetatarsal and subcalcaneal) on the plantar aspect of the foot. The distributed loading pattern of the plantar soft tissue throughout the stance phase of gait was determined. Pes planus feet had significantly more force at the subhallucal area with no difference seen under the other areas. These data are indicative of aberrant first ray mechanics in pes planus feet.

Foot type biomechanics. comparison of planus and rectus foot types.

The basic premise central to the diagnosis and treatment of most mechanogenic foot and ankle pathologies is that a given foot will display a characteristic function depending on the biomechanical alignment of the hindfoot and forefoot. However, the effects of foot type on an individuals ability to perform comfortable cadence locomotion have not been scientifically proven. Therefore, this study was conducted on 21 healthy, young subjects (10 subjects with planus foot type and 11 subjects with rectus foot type) to test whether different foot types yield distinguishable foot functions. New methods were developed to quantify biomechanical foot function during posture and comfortable cadence locomotion. The results of the study indicate that individuals with planus and rectus foot types show statistically significant differences in the biomechanical function of the foot.

Factors associated with hallux valgus in a population-based study of older women and men: the MOBILIZE Boston Study.

OBJECTIVE To examine potential risk factors for hallux valgus in community-dwelling elders. METHOD Data from 600 MOBILIZE Boston Study participants (386 women and 214 men) were analyzed. Hallux valgus was defined as >15 degrees angular deviation of the hallux with respect to the first metatarsal bone toward the lesser toes. Associations of hallux valgus with age, body mass index (BMI), race, education, pes planus, foot pain, and in women, history of high heel shoe use, were assessed using sex-specific Poisson regression with robust variance estimation for risk ratios (RR) and 95% confidence intervals (CI). RESULTS Hallux valgus was present in 58% of women and 25% of men. Higher BMI was inversely associated with presence of hallux valgus in women (P trend=0.001), with the strongest inverse association observed in those with BMI of 30.0 or more compared to those with normal BMI (RR=0.7, 95% CI: 0.5, 0.9). Women, who usually wore high-heeled shoes during ages 20-64 years compared to those who did not, had increased likelihood of hallux valgus (RR=1.2, 95% CI: 1.0, 1.5). Among men, those with BMI between 25.0 and 29.9 had increased likelihood of hallux valgus compared to those with normal BMI (RR=1.9, 95% CI: 1.0, 3.5). Men with pes planus were more likely to have hallux valgus (RR=2.1, 95% CI: 1.3, 3.3) compared to men without pes planus. CONCLUSION In women, hallux valgus was associated with lower BMI and high heel use during ages 20-64, while in men, associations were observed with higher BMI and pes planus. Our results suggest that the etiologic mechanisms for hallux valgus may differ between men and women.

Comparison of nerve transfers and nerve grafting for traumatic upper plexus palsy: a systematic review and analysis.

BACKGROUND In treating patients with brachial plexus injury, there are no comparative data on the outcomes of nerve grafts or nerve transfers for isolated upper trunk or C5-C6-C7 root injuries. The purpose of our study was to compare, with systematic review, the outcomes for modern intraplexal nerve transfers for shoulder and elbow function with autogenous nerve grafting for upper brachial plexus traumatic injuries. METHODS PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched for studies in which patients had surgery for traumatic upper brachial plexus palsy within one year of injury and with a minimum follow-up of twelve months. Strength and shoulder and elbow motion were assessed as outcome measures. The Fisher exact test and Mann-Whitney U test were used to compare outcomes, with an alpha level of 0.05. RESULTS Thirty-one studies met the inclusion criteria. Two hundred and forty-seven (83%) and 286 (96%) of 299 patients with nerve transfers achieved elbow flexion strength of grade M4 or greater and M3 or greater, respectively, compared with thirty-two (56%) and forty-seven (82%) of fifty-seven patients with nerve grafts (p < 0.05). Forty (74%) of fifty-four patients with dual nerve transfers for shoulder function had shoulder abduction strength of grade M4 or greater compared with twenty (35%) of fifty-seven patients with nerve transfer to a single nerve and thirteen (46%) of twenty-eight patients with nerve grafts (p < 0.05). The average shoulder abduction and external rotation was 122° (range, 45° to 170°) and 108° (range, 60° to 140°) after dual nerve transfers and 50° (range, 0° to 100°) and 45° (range, 0° to 140°) in patients with nerve transfers to a single nerve. CONCLUSIONS In patients with demonstrated complete traumatic upper brachial plexus injuries of C5-C6, the pooled international data strongly favors dual nerve transfer over traditional nerve grafting for restoration of improved shoulder and elbow function. These data may be helpful to surgeons considering intraoperative options, particularly in cases in which the native nerve root or trunk may appear less than optimal, or when long nerve grafts are contemplated.

Arch height index measurement system: establishment of reliability and normative values.

BACKGROUND The purposes of this study were 1) to determine the intrarater and interrater reliability of the arch height index measurement system device, 2) to establish population normative values for the arch height index in recreational runners, and 3) to compare arch height index values between the right and left feet and between genders. METHODS Eleven subjects were used to establish intrarater and interrater reliability of the arch height index measurement system. This system was then used to measure the arch height index of 100 recreational runners. RESULTS Measurements taken with the arch height index measurement system device exhibited high intrarater and interrater reliability. The mean +/- SD arch height index of the recreational runners was 0.340 +/- 0.030. Men had larger feet than women, but the arch height index between genders was similar. CONCLUSIONS The arch height index measurement system device is reliable to use between testers while simplifying the measurement procedure for recording the arch height index. The arch height index may be helpful in identifying potential structural factors that predispose individuals to lower-extremity injuries.

The Effect of Gender, Age, and Lateral Dominance on Arch Height and Arch Stiffness:

Background: Arch structure is known to vary widely. However, it may be linked to intrinsic factors such as gender, age, and lateral dominance. Understanding the association between these factors and arch structure may be useful in understanding injury biases that exist between individuals with different foot types. Methods: The foot structure of 145 subjects, 68 men and 77 women (18 to 65 years) was examined in this study. The arch height index, a measure of dorsal height normalized to foot length, and arch stiffness of both feet were measured in each subject. Comparisons of both arch height and arch stiffness were made between genders and between the dominant and nondominant feet. In addition, the relationship between both arch height and stiffness and age was examined. Results: There was no difference between the arch height index of men and women; however, the arches in women were significantly less stiff (p = 0.00). There were no statistically significant relationships between increasing age and either arch height index or stiffness. The within-subject comparisons showed that the dominant foot had a significantly higher arch height index than the nondominant foot (p = 0.00). However, arch stiffness was not different between sides. There was a significant, but weak, relationship between arch height index and arch stiffness (p = 0.00, R 2 = 0.09) with a higher arch height index corresponding to a stiffer arch. Conclusion: Understanding differences in arch structure may lend insight into the predilection for injury between genders, with increasing age, and between sides of a given subject.

Foot type biomechanics part 1: Structure and function of the asymptomatic foot

BACKGROUND Differences in foot structure are thought to be associated with differences in foot function during movement. Many foot pathologies are of a biomechanical nature and often associated with foot type. Fundamental to the understanding of foot pathomechanics is the question: do different foot types have distinctly different structure and function? AIM To determine if objective measures of foot structure and function differ between planus, rectus and cavus foot types in asymptomatic individuals. METHODS Sixty-one asymptomatic healthy adults between 18 and 77 years old, that had the same foot type bilaterally (44 planus feet, 54 rectus feet, and 24 cavus feet), were recruited. Structural and functional measurements were taken using custom equipment, an emed-x plantar pressure measuring device, a GaitMat II gait pattern measurement system, and a goniometer. Generalized Estimation Equation modeling was employed to determine if each dependent variable of foot structure and function was significantly different across foot type while accounting for potential dependencies between sides. Post hoc testing was performed to assess pair wise comparisons. RESULTS Several measures of foot structure (malleolar valgus index and arch height index) were significantly different between foot types. Gait pattern parameters were invariant across foot types. Peak pressure, maximum force, pressure-time-integral, force-time-integral and contact area were significantly different in several medial forefoot and arch locations between foot types. Planus feet exhibited significantly different center of pressure excursion indices compared to rectus and cavus feet. CONCLUSIONS Planus, rectus and cavus feet exhibited significantly different measures of foot structure and function.

Effects of Pediatric Obesity on Joint Kinematics and Kinetics During 2 Walking Cadences

UNLABELLED Shultz SP, Sitler MR, Tierney RT, Hillstrom HJ, Song J. Effects of pediatric obesity on joint kinematics and kinetics during 2 walking cadences. OBJECTIVE To determine whether differences existed in lower-extremity joint biomechanics during self-selected walking cadence (SW) and fast walking cadence (FW) in overweight- and normal-weight children. DESIGN Survey. SETTING Institutional gait study center. PARTICIPANTS Participants (N=20; mean age +/- SD, 10.4+/-1.6y) from referred and volunteer samples were classified based on body mass index percentiles and stratified by age and sex. Exclusion criteria were a history of diabetes, neuromuscular disorder, or recent lower-extremity injury. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Sagittal, frontal, and transverse plane angular displacements (degrees) and peak moments (newton meters) at the hip, knee, and ankle joints. RESULTS The level of significance was set at P less than .008. Compared with normal-weight children, overweight children had greater absolute peak joint moments at the hip (flexor, extensor, abductor, external rotator), the knee (flexor, extensor, abductor, adductor, internal rotator), and the ankle (plantarflexor, inverter, external/internal rotators). After including body weight as a covariate, overweight children had greater peak ankle dorsiflexor moments than normal-weight children. No kinematic differences existed between groups. Greater peak hip extensor moments and less peak ankle inverter moments occurred during FW than SW. There was greater angular displacement during hip flexion as well as less angular displacement at the hip (extension, abduction), knee (flexion, extension), and ankle (plantarflexion, inversion) during FW than SW. CONCLUSIONS Overweight children experienced increased joint moments, which can have long-term orthopedic implications and suggest a need for more nonweight-bearing activities within exercise prescription. The percent of increase in joint moments from SW to FW was not different for overweight and normal-weight children. These findings can be used in developing an exercise prescription that must involve weight-bearing activity.

Three-dimensional, six-degrees-of-freedom kinematics of the human hindfoot during the stance phase of level walking

Abstract The goal of this study was to develop a technique to measure the unconstrained, six-degrees-of-freedom motion of the hindfoot during level walking and to apply this technique to characterize this motion in a young healthy population. The motion was described using a joint coordinate system which provided a description of motion in terms of three angular displacements and three linear displacements. The accuracy of the technique was first determined using a six-degrees-of-freedom linkage. The motion of the hindfoot was then measured during level walking on ten young healthy volunteers. For this purpose, a motion analysis system was used to record the motion of eight reflective skin markers attached over bony landmarks on the tibia-fibula and calcaneus. The results indicate that the baseline accuracy of the technique (not including skin motion) was 1 degree for rotations and 1.4 mm for translations. From the gait data it was concluded that the patterns of hindfoot motion are similar amongst individuals in some joint parameters but not in others. Specifically, dorsiflexion/plantarflexion had a very consistent pattern, followed by inversion/eversion and to a lesser extent by compression/distraction. The other parameters (axial rotation, anterior/posterior displacement and medial/lateral displacement) demonstrated a highly variable pattern amongst the individuals tested. In terms of the range of motion of the six joint parameters it was found that angular excursions were smaller than 20 ° and that linear displacements in both anterior/posterior direction and medial/lateral direction was smaller than 3.5 mm.

Accuracy and Reliability of Three Different Techniques for Manual Goniometry for Wrist Motion: A Cadaveric Study

PURPOSE Despite the ubiquitous use of manual goniometry in measuring objective outcomes of hand surgery and therapy, there are limited data concerning its accuracy or repeatability for wrist motion. The purpose of this study was to evaluate the accuracy and reliability (both inter- and intra-rater) in measuring wrist flexion and extension using 3 manual goniometric alignment techniques (ulnar, radial, and dorsal-volar) in cadaveric upper extremities, using fluoroscopic verification of posture as a gold standard. In addition, we sought to assess the accuracy and reliability of the dorsal-volar technique for measurement of radioulnar deviation. METHODS External fixators were applied to 10 cadaveric wrists with intramedullary cannulated rods in the radius and third metacarpal for gold-standard fluoroscopic verification of posture. Manual goniometric measurements with each technique were captured by 2 raters (a hand surgeon and a hand therapist) for reliability measurements and by a single rater for accuracy. Wrists were positioned at angles of maximum flexion, extension, and radial and ulnar deviation for reliability testing and at preselected angles across the range of motion for accuracy testing. At each position, wrist angle was measured with a 1 degrees increment goniometer, and fluoroscopic angles were measured digitally. Intraclass correlation coefficients and root mean square values were calculated for all combinations, and analysis of variance was used to test differences between techniques. RESULTS No technique was statistically less accurate than any other (6 degrees to 7 degrees ). Each method was found to have high intra-rater reliability. For measurement of wrist flexion and extension, the dorsal-volar technique demonstrated the greatest inter-rater reliability, as compared to ulnar and radial, respectively. CONCLUSIONS Although each measurement technique demonstrated a similar degree of accuracy and intra-rater reliability, the dorsal-volar technique demonstrates the greatest level of inter-rater reliability for measurement of wrist flexion and extension. This information is important clinically, as measurements are regularly exchanged between hand surgeons and therapists as a basis for decisions regarding patient care.