Finite element model-based evaluation of tissue stress variations to fabricate corrective orthosis in feet with neutral subtalar joint.

BACKGROUND: The subtalar joint position during static stance is a crucial determinant of the peak plantar pressures and forms ideal reference point for any intervention in foot-related problems for leprosy-affected patients. OBJECTIVES: The study pursued the hypothesis through a three-dimensional model that stress will be minimal in the distal joints of the foot when the subtalar joint is in neutral static stance position. STUDY DESIGN: Finite element model. METHODS: The computed tomography images of the feet for five patients suffering from Hansen's disease having no muscle weakness and joint restriction were acquired. The gray intensities corresponding to the bones of the foot from the computed tomography images were three-dimensionally reconstructed. The three-dimensional model of the human foot, incorporating the realistic geometry, and the material properties of the hard tissues were then analyzed using a finite element solver for the stress distribution on bones of the foot. RESULTS: The results demonstrate that the position of the calcaneum in the static stance position does contribute to the varying stress in the foot. CONCLUSION: The stresses in the bones of the foot are minimal while the subtalar is in neutral position; this position will be suitable for foot orthotic fabrication. Clinical relevance The clinicians, therapists, and podiatrists having less engineering skills can quickly assess the patient and get optimal results on the stress associated with the joints of the foot.

The role of radiology in nerve function impairment and its musculoskeletal complications in leprosy.

Conventional techniques, such as plain radiography and bone-scintigraphy, were used in the past to evaluate skeletal changes in patients with leprosy. More recent publications focus on radiological imaging of affected nerves, and involve advanced modalities such as Computed Tomography (CT-scan), Ultrasonography (US), and Magnetic Resonance Imaging (MRI). US and MRI can play an especially important role in the evaluation of nerve involvement in newly diagnosed patients, and also during leprosy reactions. This is important, because when nerve involvement is diagnosed in time, it may be reversible with adequate treatment. Radiological modalities can also play an important role during the followup of patients with leprosy with nerve function impairment. Skeletal and soft-tissue abnormalities occur, even after treatment. The so-called neuropathic foot is a well known consequence. Because of nerve function impairment, there is a constant risk of developing ulcers and subsequent osteomyelitis, or neuro-osteoarthropathy (Charcot foot or tarsal disintegration), which can lead to the amputation of the affected limb. Different radiological modalities can be used during the evaluation and follow-up of patients with leprosy with a neuropathic foot. With this up-to-date review, we highlight the importance and potential role of radiological imaging techniques in leprosy.

Exotic pathology of the hand and foot. A pictorial review.

In this article, the imaging findings of the most frequently encountered import pathology of the hand and foot are reviewed, including leprosy, loiasis, snake bites or penetration of spines of sea urchins in the hand and foot. Our objective is to familiarize the radiologist of the Western countries with these diseases, which are still prevalent in developing areas. Due to the rising traveling to foreign countries and continuous immigration, it is important that these disorders be considered in the differential diagnosis in a specific population of asylum-seekers, economic refugees and any other group of persons traveling around the globe. Imaging findings on conventional radiography will be emphasized.

Radiological changes in hands and feet in disabled leprosy patients: a clinico-radiological correlation.

Seventy-six consecutive leprosy patients with disabilities were subjected to radiological examination of hands and feet, and bone changes were found in 63 of them (82.9%). Specific, nonspecific and osteoporotic bone changes were observed in 22.4%, 78.9% and 28.9% of cases respectively. Bone cysts (10.5%), subarticular erosions (10.5%) and enlargement of nutrient foramina (5.3%) were the common specific bone changes whereas bone absorptive changes (59.2%), soft tissue changes (39.5%) and concentric absorption (39.5%) were the most frequent nonspecific bone changes. Specific bone changes were more common in older patients (age 40 years) and nonspecific bone changes correlated with duration of disease, duration of deformity, and disability index. Osteoporotic bone changes were found to be affected by ageing and severity of disability of hands and feet.

[Bone changes in Hansen's disease]. / Knochenveränderungen bei Morbus Hansen.

Bone lesion is a frequent organic manifestation in leprosy. Osseal destructions caused by granulomatous process induced by M. leprae are so-called specific lesions in contrast to non-specific lesions based on nerval or arterial diseases. The specific osseal alterations are characterized by cystic brightenings in roentgenograms while non-specific osseal changes show absorption to bone structure as akroosterolysis and osteoporosis. Typical radiologic findings in different stages of mutilation are demonstrated.

Arteriographic evaluation of vascular changes in leprosy.

Two hundred and eighty-four arteriograms were performed in the hands and feet 178 leprosy patients. Narrowing and tortuosity of the digital vessels, especially in the presence of bone absorption, were constant features. Digital tufts revealed signs of ischemia. However, in the presence of infection, hyperemia was a definite observation. Diminution in the caliber of the digital arteries and thinning or absence of the vascular end loops prove that ischemia plays a vital role in the production of various lesions in leprosy.

Radiological changes in serial x-rays of the foot and tarsus in leprosy.

Most bone abnormalieis seen in serial films of the feet in leprosy were static being the end result of old disease. Changes over a period of time were observed in serial fims of 214 feet and these changes were due to a combination of infection, neuropathic changes and avascular necrosis occurring in anaesthetic feet. The bone abnormalities seen were absorption of toes and metatarsals; bone destruction; a neuropathic arthropathy of toes and metatarsals and various patterns of tarsal disintegration.