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Radiographic Anatomy of the Foot and Ankle—Part 5
The Phalanges
Background
The normal radiographic anatomy of the foot and ankle, aside from my previous work, has been addressed only superficially or sparingly in the medical literature. This project correlates the detailed radiographic anatomy of the entire adult foot and ankle (two-dimensional) to osteology (three-dimensional).
Methods
Each bone's position was determined after meticulous examination and correlation to an articulated skeleton relative to the image receptor and direction of the x-ray beam, with correlation to the radiograph for confirmation.
Results
Images of each foot and distal leg bone (“front” and “back” perspectives) are presented alongside a corresponding radiographic image for comparison. The normal gross and radiographic anatomy is correlated and described for each radiographic positioning technique.
Conclusions
Foundational knowledge is provided that future researchers can use as a baseline (“normal”) and that students and practitioners can use for comparison when interpreting radiographs and distinguishing abnormal findings. The results of the original project, owing to its broad scope, have been divided into five parts: the lower leg, the greater tarsus, the lesser tarsus, the metatarsals, and the phalanges (the focus of this article).
Background:
Anthropometric status can influence gait biomechanics, but there is relatively little published research regarding foot and ankle characteristics in the obese pediatric population. We sought to compare the structural and functional characteristics of the foot and ankle complex in obese and non-obese children.
Methods:
Twenty healthy children (ten obese and ten normal weight) were recruited for a cross-sectional research study. Anthropometric parameters were measured to evaluate active ankle dorsiflexion, arch height (arch height index, arch rigidity index ratio, and arch drop), foot alignment (resting calcaneal stance position and forefoot-rearfoot alignment in unloaded and loaded positions), and foot type (malleolar valgus index). Independent t tests determined significant differences between groups for all assessed parameters. Statistical significance was set at P < .0125.
Results:
Compared with non-obese participants, obese participants had significantly greater arch drop (mean ± SD: 5.10 ± 2.13 mm versus 2.90 ± 1.20 mm; P =.011) and a trend toward lower arch rigidity index ratios (mean ± SD: 0.92 ± 0.03 versus 0.95 ± 0.02; P = .013). In addition, obese participants had significantly less active ankle dorsiflexion at 90° of knee flexion versus non-obese participants (mean ± SD: 19.57 ± 5.17 versus 29.07 ± 3.06; P < .001). No significant differences existed between groups for any other anthropometric measurements.
Conclusions:
The decreased active ankle dorsiflexion in the obese group can increase foot contact for a longer period of the stance phase of gait. Obese participants also presented with a more flexible foot when bearing weight. (J Am Podiatr Med Assoc 102(1): 5–12, 2012)
Background
Vitamin D is an essential vitamin that targets several tissues and organs and plays an important role in calcium homeostasis. Vitamin D deficiency is common, particularly at higher latitudes, where there is reduced exposure to ultraviolet B radiation. We reviewed the role of vitamin D and its deficiency in foot and ankle pathology.
Methods
The effects of vitamin D deficiency have been extensively studied, but only a small portion of the literature has focused on the foot and ankle. Most evidence regarding the foot and ankle consists of retrospective studies, which cannot determine whether vitamin D deficiency is, in fact, the cause of the pathologies being investigated.
Results
The available evidence suggests that insufficient vitamin D levels may result in an increased incidence of foot and ankle fractures. The effects of vitamin D deficiency on fracture healing, bone marrow edema syndrome, osteochondral lesions of the talus, strength around the foot and ankle, tendon disorders, elective foot and ankle surgery, and other foot and ankle conditions are less clear.
Conclusions
Based on the available evidence, we cannot recommend routine testing or supplementation of vitamin D in patients with foot and ankle pathology. However, supplementation is cheap, safe, and may be of benefit in patients at high risk for deficiency. When vitamin D is supplemented, the evidence suggests that calcium should be co-supplemented. Further high-quality research is needed into the effect of vitamin D in the foot and ankle. Cost-benefit analyses of routine testing and supplementation of vitamin D for foot and ankle pathology are also required.
Giant Cell Tumor of the Tendon Sheath Around the Foot and Ankle
A Report of Three Cases and a Literature Review
The foot and ankle are rare sites of involvement for giant cell tumor of tendon sheath. We present three rare cases of giant cell tumor of tendon sheath arising from the tendon sheaths of the flexor hallucis longus, peroneus brevis, and extensor hallucis brevis tendons, along with a literature review of such cases in the foot and ankle region. All of the patients were treated with surgical excision of the mass and were asymptomatic after minimum follow-up of 18 months. Giant cell tumor of tendon sheath involving the foot and ankle region is a rare clinical entity, and good results can be expected after surgical excision.
Background: Foot and ankle volume may be an important measurement for conditions such as lower-extremity trauma or pathologic abnormalities. Water volumetry, often used for this measure, is accurate but not always convenient. We used figure-of-eight tape measurement, prism approximation, foot size measurement (Brannock device), and optoelectric measurement (Perometer) with the standard of water volumetry to compare foot and ankle volumes.
Methods: All five techniques were used to measure both the feet and ankles of ten asymptomatic men and women. Reliability was determined by repeating several trials, and validity was determined by comparing all of the techniques with water volumetry (the established standard). Regression equations were found that related each technique to water volumetry.
Results: All of the techniques were reliable (intraclass correlation coefficient[3,1] = 0.96–0.99). The figure-of-eight technique showed the highest agreement with water volumetry (R 2 = 0.96), and the prism method, the lowest (R 2 = 0.73).
Conclusions: Although any of these techniques should be acceptable for monitoring foot and ankle volume in normal limbs, the figure-of-eight method comes closest to reproducing the results of water volumetry. We believe that this technique would also be best in the presence of foot deformities, but this remains to be studied. (J Am Podiatr Med Assoc 98(2): 85–94, 2008)
Magnetic resonance imaging is playing an increasingly important role in evaluation of the injured athlete’s foot and ankle. Magnetic resonance imaging allows accurate detection of bony abnormalities, such as stress fractures, and soft-tissue abnormalities, including ligament tears, tendon tears, and tendinopathy. The interpreter of magnetic resonance images should systematically review the images, noting normal structures and accounting for changes in soft-tissue and bony signal. (J Am Podiatr Med Assoc 97(1): 59–67, 2007)
Osteonecrosis is acknowledged as a relatively uncommon disorder caused by various factors, including autoimmune diseases, drug-induced diseases, inherited metabolic disorders, coagulation disorders, and underlying malignancies. To our knowledge, no previous research has investigated osteonecrosis stemming from extracorporeal membrane oxygenation. Herein, we report a rare case of postperipheral venoarterial extracorporeal membrane oxygenation–induced multifocal osteonecrosis in the foot and ankle that demonstrated a low serpiginous peripheral signal on T1-weighted images and a double-line sign on fat-suppressed or T2-weighted magnetic resonance images. Conservative treatment was applied, and the patient was mostly recuperated after 6 months.
The general development of the lower limb and the specific development of the foot and ankle are discussed for each horizon in the embryonic and fetal periods of development. Lower limb general development is discussed only to the extent necessary for the understanding of foot and ankle development.
