Chondrosarcoma of the foot.

Chondrosarcomas have been seen clinically as aggressive tumors, with radiographic and histologic findings consistent with malignancy; however, they may have an insidious clinical course, with relatively benign radiographic and histopathologic findings. Rarely, a chondrosarcoma may present as a primary lesion of the foot. It is important to recognize these lesions as malignancies.

Use of gait patterns to reveal possible disorders in the geriatric patient.

Changes in gait occur frequently with advancing age and are often associated with falls, loss of independence, morbidity, and even mortality. Gait changes may occur as part of the natural process of aging or may be associated with underlying pathology. Careful observation of gait can provide insight into the patient's overall state of health.

The windlass mechanism of the foot. A mechanical model to explain pathology.

This article presents a mechanical model that can be used to understand the foot, to help develop methods of treatment of foot pathology, and to provide direction for future research in foot mechanics and pathology. The anatomy and mechanical function of the windlass mechanism of the foot are analyzed using principles of mechanical engineering. The principles of force couples and free-body diagrams are explained and then applied to the foot.

Biomechanics of the normal and abnormal foot.

The foot is an engineering marvel that allows the body to perform many physical activities over a wide variety of terrain with remarkable efficiency. The functions of the foot and the lower extremity are biomechanically integrated; thus normal lower-extremity function requires normal foot function and vice versa. Because the subtalar joint is the main pedal joint allowing the triplanar translation of motion between the foot and lower extremity, normal subtalar joint function is critical to normal foot and lower-extremity function.

The increased prevalence of severe necrotizing infections caused by non-group A streptococci.

The authors report on 20 patients who were admitted to the University of Texas Health Science Center at San Antonio during a recent 4-month period with foot infections caused predominantly by non-group A streptococci. This number of patients was significantly greater than the number admitted to the same institution with the same diagnosis during the preceding 3 years. All patients had type 2 diabetes mellitus.

Center of pressure and its theoretical relationship to foot pathology.

The measurement of center of pressure has been widely used in the evaluation of foot function. This article will describe center of pressure and indicate how it can be used to calculate moments about the joint axes of the foot. Various uses of center of pressure described in the literature will be examined.

Limb salvage with Chopart's amputation and tendon balancing.

For several decades, Chopart's amputation has met with some skepticism owing to reports of significant equinus deformity developing soon after the procedure is performed. However, with appropriate tendon balancing, which generally includes anterior tibial tendon transfer and tendo Achillis lengthening, this level of amputation is often more functional than slightly more distal amputations, such as Lisfranc or short transmetatarsal amputations. The authors offer a rationale for this observation, which includes a discussion of the longitudinal and transverse arch concept of the foot.

Characterization of plantar verrucae among individuals with human immunodeficiency virus.

Plantar verrucae, caused by human papillomavirus (HPV), are commonly found in patients who have tested positive for the antibodies to human immunodeficiency virus (HIV). A better understanding of the characteristics of plantar verrucae in HIV+ patients in needed. A pilot study was conducted concentrating on three characteristics--the size, the number, and the clinical type--of verrucae present in this population.

Foot and ankle injuries related to rock climbing. The role of footwear.

Interest in rock climbing has grown dramatically over the past decade. Although considerable research has been conducted on upper-extremity injuries sustained during rock climbing, there has been no comprehensive evaluation of lower-extremity injuries and related biomechanics. The authors performed a retrospective investigation of rock-climbing injuries using a survey of 104 active rock climbers of varying levels of expertise.

Occupational exposure to HIV, hepatitis B, hepatitis C, and tuberculosis.

This article reviews risk of occupational exposure to bloodborne pathogens, specifically HIV, hepatitis B, and hepatitis C to healthcare workers. Information regarding assessing the risk of exposure, appropriate actions to take if an exposure occurs, the most recent recommendations for treatment and follow-up postexposure, and prevention strategies for avoiding exposure are presented. Additionally, current recommendations for the prevention of the transmission of tuberculosis in healthcare workers and the regulatory guidelines governing this topic are discussed.

Plantar verrucae and HIV infection.

No single treatment of plantar verrucae has proven to be effective in all situations, which represents a greater challenge when treating patients infected with HIV. In this patient population, plantar verrucae appear to be more aggressive, and recurrence is frequently observed. Mosaic-type plantar verrucae, which are usually more resistant to treatment, are common in this population.

Onychomycosis in HIV-positive patients.

Onychomycosis is a common podiatric condition that has become an increasing problem as the number of patients with HIV infection has grown. Although it is not among the most severe infections that affect HIV-positive patients, it tends to be more extensive, refractory to treatment, and has a unique clinical presentation in this patient population. It is important for the podiatric physician to be aware of the epidemiology, clinical presentation, diagnosis, and treatment of onychomycosis in HIV-positive patients.

Molecular biology of HIV.

This article describes the molecular aspects of the life cycle of HIV. Evolution theories of HIV origin, specific steps in the infection cycle, and regulation of expression are discussed. The article concludes with a summary of the current theories of the pathogenesis of HIV infection and the breakdown of the immune system.

Poly-L-lactic acid rod fixation results in foot surgery.

The purpose of this study was to evaluate the effectiveness and possible complications of polylactic absorbable devices in surgical procedures involving fixation of the foot. This was a prospective study in which biodegradable rods of poly-L-lactide were used in the fixation of 41 metatarsal osteotomies and digital arthrodeses and one midtarsal fusion in 23 patients. The follow-up time ranged from 6 months to 23 months.

Living skin equivalents and their application in wound healing.

Living skin equivalents are the combination of the bioengineering and tissue-transplantation sciences. Their uses have applications in aiding wound healing for ulcerations caused by thermal injury, diabetic neuropathy, venous hypertension, and pressure. Products can be divided into keratinocyte sheets, dermal replacements, or composite material.

Measurement of the expansion of the calcaneal fat pad upon weightbearing.

The width of the calcaneal fat pad during weightbearing differs from its width during nonweightbearing. In this study, the medial-to-lateral width of the calcaneal fat pad was measured during weightbearing as well as nonweightbearing, and the two measurements were compared. The difference between weightbearing width and nonweightbearing width was found to vary widely across individuals.

Epidemiology of onychomycosis in special-risk populations.

A person's susceptibility to onychomycosis and the course of the disease once the nails are infected are functions of the interaction of the fungal agent, the host, and environmental factors. The disease is reported to have an overall prevalence of 2% to 13%, but the prevalence is much higher in certain populations, such as older people and those with immunosuppressive conditions. Although onychomycosis may be merely a nuisance and an embarrassment for healthy individuals, some morbidity is seen with all population groups, but especially high-risk patients: diabetics, patients infected with human immunodeficiency virus (HIV), patients with acquired immunodeficiency syndrome (AIDS), and patients with other types of immunosuppression (eg, transplant recipients and patients on long-term corticosteroid therapy).

The nonfixated Austin bunionectomy: a retrospective study of one-hundred procedures.

A retrospective evaluation of 64 randomly selected patients with 100 nonfixated Austin bunionectomy procedures was performed. A radiographic and a clinical evaluation were performed, including an analysis of preoperative and postoperative angles as well as postoperative complications. This study demonstrates a similar complication rate for nonfixated Austin bunionectomies as compared with previous studies with internal fixation.

Torsion of the tendon of peroneus brevis.

The authors present a previously undescribed torsion located within the tendon of peroneus brevis. The musculotendinous unit of peroneus brevis was isolated from 46 lower extremities of cadavers. A goniometer was constructed and utilized to quantify the degree of torsion located within each peroneus brevis tendon.

Dilute lidocaine ankle blocks in the diagnosis of sympathetically maintained pain.

The author has developed a technique of dilute anesthetic ankle block that appears, on the basis of these preliminary observations, to relieve pathologic pain that may be maintained by the sympathetic nervous system. Symptomatic relief following the use of this injection confirms that the patient's problem is not somatic and that further evaluation and treatment of sympathetically maintained pain syndrome may be indicated.

Management of painful diabetic neuropathy. A treatment algorithm.

Peripheral neuropathy manifests as a painful syndrome in a significant number of individuals suffering from diabetes mellitus. Painful diabetic neuropathy may interfere with sleep, work, and activities of daily living. Patients and practitioners alike often view this challenging disorder as incurable.

Achilles and peroneal tendon injuries in the athlete. An expert's perspective.

Peroneal tendonopathy or injuries are not common but may be troubling to the sports enthusiast. Prompt diagnosis and treatment usually result in complete recovery with conservative measures. Biodynamic orthosis with deep heel cups and a long lateral flange extension often are required for return to activity.

Renin and angiotensin II receptor expression in the brains of DES-treated Syrian hamsters.

Background: The renin angiotensin system (RAS) promotes vasoconstriction. Expression of RAS is induced by different factors.

Methods: In this study, forebrain sections of hamster brains were studied by immunohistochemical methods to determine the location of renin-positive and angiotensin II receptor-positive cells.

Unusual presentation of calcaneal osteomyelitis. Twenty-five years after inoculation.

An unusual presentation of calcaneal osteomyelitis is described, where-by the infection remained undiagnosed for 25 years. The 36-year-old patient recently sought medical treatment for a reported ankle sprain, but the pain was recalcitrant to conservative care. Further investigation yielded a history significant for stepping on a chicken bone as a child, which entered the inferior lateral heel.

An alternative method for reducing plantar pressures in neuropathic ulcers.

Neuropathic foot ulcers, a serious complication of impaired pedal sensation, are the most common complication of diabetes mellitus leading to hospitalization. One of the goals in treating neuropathic ulcers is to reduce or eliminate pressure from the ulcer site to prevent further breakdown and allow healing. These treatments must address several forms of stress-vertical pressure, shearing force, and tissue strain.