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- Author or Editor: Nachiappan Chockalingam x
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Foot Orthoses
A Review Focusing on Kinematics
Orthoses have been broadly used by clinicians to treat mechanical misalignments, such as abnormal foot pronation. As such, the influences of orthoses on lower-limb kinematics have been studied numerous times, with many articles reporting nonsystematic results; the aim of this review, therefore, was to examine the recognized effects of foot orthoses on lower-limb kinematics. The findings from this review suggest that foot orthoses seem to have certain generic and common effects on the lower limb when designed to control rearfoot pronation. We also discuss the possible reasons behind the lack of consistent results between studies. Based on the findings, a list of recommendations is presented for future research on foot orthoses to facilitate comparisons between studies and enable the scientific and clinical communities to better comprehend the effects that these variables might have on the kinematics and, possibly, the treatment outcomes. (J Am Podiatr Med Assoc 101(4): 341–348, 2011)
Clinical Assessment of Ankle Joint Dorsiflexion
A Review of Measurement Techniques
Ankle dorsiflexion measurement is important for clinical and research use. With so much evidence on the unreliability of goniometric measurements, a systematic review was performed to investigate various alternative techniques for measuring ankle dorsiflexion in the nonneurologic patient. All of the major databases were queried electronically to identify studies that used any method of ankle dorsiflexion measurement in the nonneurologic subject. Keywords included ankle dorsiflexion NOT cerebral palsy NOT stroke, the latter to exclude neurologic conditions. In 755 studies that used some form of ankle joint dorsiflexion measurement, ten different techniques were identified that included various apparatuses designed specifically for this purpose. Reliability testing of these techniques involved test-retest trials with small student populations as subjects, which returned high intraclass correlation coefficient scores. However, their methodological quality would have benefitted from the use of an actual patient population and comparison with a reference standard. When validating ankle dorsiflexion measurement techniques, actual patient populations should be used, otherwise papers would score poorly on methodological quality assessment. Standardizing patient position, foot posture, amount of moment applied, and reference landmarks will ensure that various trial results can be compared directly. (J Am Podiatr Med Assoc 101(1): 59–69, 2011)
Functional Hallux Limitus
A Review
Functional hallux limitus is defined as a functional inability of the proximal phalanx of the hallux to extend on the first metatarsal head during gait. The theory concerning this anomaly and the altered gait characteristics that may result appears to have influenced the understanding of sagittal plane podiatric biomechanics. Although there is an increase in the body of evidence to support the proposed gait alterations, a detailed review suggests the need for further work. The aim of this article is to review the functional hallux limitus literature and its reported effects on gait. Furthermore, we explore some of the key and inherent problems with obtaining accurate data for joint motion measurement in the foot. With evidence-based practice now at the forefront of both clinical and academic practice, it is imperative to review the literature that underpins a particular commonly held or historical belief, in order to substantiate and validate subsequent diagnoses and treatments provided in light of this information. This is also true to advance the understanding of a particular anomaly or pathology and to inform so as to facilitate the provision of better care to patients. (J Am Podiatr Med Assoc 99(3): 236–243, 2009)
Background: This study investigated the effects of two low-Dye and two high-Dye strapping techniques that are commonly used to treat pronatory sequelae.
Methods: Plantar pressure distribution in normal adults with a pronated foot type was assessed with a commercially available pressure platform system. Twenty study participants first walked across the platform barefoot and then with each of the four strapping conditions applied. The footprints were averaged and divided into seven areas for analysis.
Results: Paired t tests found significant differences between the barefoot and strapping conditions. Overall, there was a general lateralization of pressures indicating an antipronation effect from all strapping conditions. Low-Dye strap 2, used to limit the degree of calcaneal eversion, produced the most significant changes at the foot pressure areas analyzed.
Conclusions: The data reported in this study suggest that the four strapping techniques offer different levels of control, and this should be considered during the decision-making process and clinical management of pronatory conditions. It was the contention of this study that low-Dye strap 2 was the most effective strapping technique to control foot mechanics associated with a pronated foot type. (J Am Podiatr Med Assoc 99(5): 391–398, 2009)
Background:
Although assessment of passive maximum foot dorsiflexion angle is performed routinely, there is a paucity of information regarding adolescents’ foot and foot segment motion during this procedure. There are currently no trials investigating the kinematics of the adolescent foot during passive foot dorsiflexion.
Methods:
A six-camera optoelectronic motion capture system was used to collect kinematic data using the Oxford Foot Model. Eight female amateur gymnasts 11 to 16 years old (mean age, 13.2 years; mean height, 1.5 m) participated in the study. A dorsiflexing force was applied to the forefoot until reaching maximum resistance with the foot placed in the neutral, pronated, and supinated positions in random order. The maximum foot dorsiflexion angle and the range of movement of the forefoot to hindfoot, tibia to forefoot, and tibia to hindfoot angles were computed.
Results:
Mean ± SD maximum foot dorsiflexion angles were 36.3° ± 7.2° for pronated, 36.9° ± 4.0° for neutral, and 33.0° ± 4.9° for supinated postures. One-way repeated-measures analysis of variance results were nonsignificant among the 3 groups (P = .70), as were the forefoot to tibia angle and hindfoot to tibia angle variations (P = .091 and P = .188, respectively). Forefoot to hindfoot angle increased with the application of force, indicating that in adolescents, the forefoot does not lock at any particular posture as portrayed by the traditional Rootian paradigm.
Conclusions:
Participants had very flexible foot dorsiflexion, unlike those in another study assessing adolescent athletes. This finding, together with nonsignificant statistical results, implies that foot dorsiflexion measurement may be performed at any foot posture without notably affecting results. (J Am Podiatr Med Assoc 103(5): 394–399, 2013)
Posterior Tibial Tendon Dysfunction
A Review
Posterior tibial tendon dysfunction is a progressive deformity that can result in the development of a pathologic flatfoot deformity. Numerous publications have studied the effects of clinical interventions at specific stages of progression of posterior tibial tendon dysfunction, but there is still uncertainty regarding the clinical identification of the condition. It is clear that more information regarding the etiology, progression, and risk factors of posterior tibial tendon dysfunction is required. Clear evidence exists that suggests that the quality of life for patients with posterior tibial tendon dysfunction is significantly affected. Furthermore, evidence suggests that early conservative intervention can significantly improve quality of life regarding disability, function, and pain. This would suggest that significant cost burden reductions could be made by improving awareness of the condition, which would improve early diagnosis. Early conservative intervention may help reduce the number of patients requiring surgery. This review focuses on the etiologic factors, epidemiologic features, and pathogenesis of posterior tibial tendon dysfunction. It aims to analyze, discuss, and debate the current understanding of this condition using the available literature. In addition, there is a discussion of the evidence base surrounding disease characteristics associated with the different clinical stages of posterior tibial tendon dysfunction. (J Am Podiatr Med Assoc 101(2): 176–186, 2011)
Assessment and Diagnosis of Posterior Tibial Tendon Dysfunction
Do We Share the Same Opinions and Beliefs?
Background: Posterior tibial tendon dysfunction is a disabling pathologic flatfoot disorder. Evidence supports the notion that this condition is poorly diagnosed by health-care professionals. In addition, opinion is divided as to the most appropriate assessment and diagnostic techniques used to reflect the progression or stage of the condition. Hence, this study intended to explore the views and opinions of health-care professionals who may be involved in its assessment and diagnosis.
Methods: A two-phase sequential mixed methods design was used that combined a questionnaire survey and a focus group interview.
Results: The questionnaire data were analyzed using the Kendall levels of concordance and the Cohen kappa statistic, and the focus group data were analyzed using thematic analysis, which led to three main themes: resource implications, scope of practice, and awareness of the condition.
Conclusions: This study highlights what may have been suspected previously but that has never been investigated in a structured manner. One approach to the assessment and diagnosis of posterior tibial tendon dysfunction is not necessarily the best, and depending on the clinical teams, different guidance may be required to ensure that patients are receiving the most appropriate and best care.
Background:
Weakness of the toe flexor muscles has been attributed to the development of toe pathologies, and it responds well in the clinic to toe grip exercises. However, it is unknown whether exercising the toe flexor muscles improves the ability to grip and alter function. The aim of this study was to assess the effect of toe flexor exercises on apical plantar pressure, as a measure of grip, while seated and during gait.
Methods:
Twenty-three individuals with no known toe pathologies were recruited. Static peak pressure, time spent at peak pressure, and pressure-time integral while seated, as well as dynamic forefoot maximal force, contact area, and percentage contact time, were recorded before and after exercise. Toe grip exercises with a therapy ball were completed daily for 6 weeks.
Results:
Static peak pressure significantly increased after exercise on the apex of the second and third digits, as did the pressure-time integral. Dynamic peak force and contact area did not alter after exercise around the metatarsals and toes, yet percentage contact time significantly increased for each metatarsal after completing daily toe grip exercises.
Conclusions:
Exercises to improve the grip ability of the toes increased the static peak pressure on the apex of the second and third digits as well as the percentage contact time of the metatarsals during gait. The ability to increase apical peak pressure and contact time after exercises could assist in improving forefoot stability and gait efficiency and in reducing toe pathology progression.
Background:
In vitro biomechanical testing of the human foot often involves the use of fresh frozen cadaveric specimens to investigate interventions that would be detrimental to human subjects. The Thiel method is an alternative embalming technique that maintains soft-tissue consistency similar to that of living tissue. However, its suitability for biomechanical testing is unknown. Thus, the aim of this study was to determine whether Thiel-embalmed foot specimens exhibit kinematic and kinetic biomechanical properties similar to those of fresh frozen specimens.
Methods:
An observational study design was conducted at a university biomechanics laboratory. Three cadavers had both limbs amputated, with one being fresh frozen and the other preserved by Thiel's embalming. Each foot was tested while undergoing plantarflexion and dorsiflexion in three states: unloaded and under loads of 10 and 20 kg. Their segment kinematics and foot pressure mapping were assessed simultaneously.
Results:
No statistically significant differences were detected between fresh frozen and Thiel-embalmed sample pairs regarding kinematics and kinetics.
Conclusions:
These findings highlight similar kinematic and kinetic properties between fresh frozen and Thiel-embalmed foot specimens, thus possibly enabling these specimens to be interchanged due to the latter specimens' advantage of delayed decomposition. This can open innovative opportunities for the use of these specimens in applications related to the investigation of dynamic foot function in research and education.
The Effect of Heel Height on Gait and Posture
A Review of the Literature
This article explores relevant full-text literature to reveal the effects of heel height on gait and posture and the kinetics and kinematics of the foot, ankle, knee, hip, and spine. Furthermore, special attention will be given to the implications of increased heel height for clinicians treating locomotor disorders and provide information to aid clinical decision making. Full-text articles accessed from databases including AMED, ASSIA, Blackwell Synergy, BNI, Voyager, CINAHL, ScienceDirect, and Taylor Francis inform the review. (J Am Podiatr Med Assoc 99(6): 512–518, 2009)
