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Biomedical subjects

David G Armstrong

Publications and source records attributed to David G Armstrong.

At least 73 records · Page 4Linked to original sources

Computerized activity monitoring preoperatively and postoperatively.

One of the central goals of reconstructive foot and ankle surgery is restoration of or improvement in the quality of physical activity. Until recently, objective assessment of how well this goal has been attained has been elusive at best. Recent advances in activity monitoring have advanced sufficiently to help many clinicians and researchers objectively measure and potentially modulate activity. In this brief article, we describe our current experience with computerized activity monitoring. Use of modalities such as these may ultimately be able to monitor and dose levels of activity just as we do with a drug.

Ankle↗

Osseous metaplasia in plantar fibromatosis: a case report.

A case report about extensive osseous metaplasia of a plantar fibromatosis is presented. The authors are unaware of previous reports in the literature describing osseous metaplasia within plantar fibromatosis in this manner. This case shows that plantar fibromatosis may undergo osseous metaplasia in a fashion similar to fibromatous lesions elsewhere.

Bone and Bones↗

The high-low amputation ratio: a deeper insight into diabetic foot care?

The purpose of this study was to propose and evaluate a high to low (Hi-Lo) amputation ratio as a potential additional quality measure giving further insight into high-risk foot surveillance beyond foot screening examinations. As part of the Dartmouth Atlas of Health Care project, a secondary analysis was performed on Medicare administrative data. Amputation rates were adjusted for age, gender, and race. This included 37,808 minor (foot-level) amputations and 44,599 major amputations from 1996 to 1997. We also calculated the longitudinal national trends in the Hi-Lo ratio with data from the Centers for Disease Control and Prevention from 1992 to 2002. The adjusted mean Hi-Lo ratio was 1.35 (standard deviation, 0.42). The lowest ratio was 0.56, and the highest ratio was 3.43. The correlation coefficient for the Hi-Lo ratio with major amputation rate was 0.48 (P < .0001; R2 = 0.23). Similar correlations were found for the highest and lowest percentiles for major and minor rates. The Centers for Disease Control and Prevention data of the Hi-Lo ratio using the crude and age-adjusted rates suggest stable trends in the ratio over a decade. The Hi-Lo measure demonstrates face validity, yet only a small proportion of the variance is described by local propensity to perform major amputation or by major amputation rates alone. The United States has relied on a foot screening measure alone, perhaps explaining why major amputation rates have not substantively declined. If we are to reduce the amputation burden, we should begin with a straightforward measure that can be implemented at most any center.

Amputation, Surgical↗

Use of a maggot motility index to evaluate survival of therapeutic larvae.

Maggot debridement therapy is rapidly increasing in popularity at major diabetic foot and wound care centers worldwide. However, we are unaware of specific guidelines on the short-term storage of larvae. We sought to evaluate differences in maggot motility over time in larvae refrigerated versus those stored at room temperature. We also introduce a simple surrogate method for evaluating maggot vitality that may be useful for in vivo studies if validated in future works. We randomly selected ten larvae from the same shipment at ten different times in 9 days. Larvae were placed on a translucent acetate grid, and their total excursion in 30 sec was measured. This was converted into a Maggot Motility Index. In the refrigerated group, the index remained at or above 40 mm/min for approximately 60 hours from baseline, when there was a significant decrease. This same phenomenon occurred during the first 12 hours in the nonrefrigerated group. There were significant differences in motility between refrigerated and nonrefrigerated larvae immediately after baseline until day 8. Larvae are more practical for repeated clinical use if kept refrigerated between applications.

Animals↗

Plantar pressure changes using a novel negative pressure wound therapy technique.

This study evaluated changes in pressure imparted to diabetic foot wounds using a novel negative pressure bridging technique coupled with a robust removable cast walker. Ten patients had plantar pressures assessed with and without a bridged negative pressure dressing on the foot. Off-loading was accomplished with a pressure-relief walker. Plantar pressures were recorded using two pressure-measurement systems. The location and value of peak focal pressure (taken from six midgait steps) were recorded at the site of ulceration. Paired analysis revealed a large difference (mean +/- SD, 74.6% +/- 6.0%) between baseline barefoot pressure and pressure within the pressure-relief walker (mean +/- SD, 939.1 +/- 195.1 versus 235.7 +/- 66.1 kPa). There was a mean +/- SD 9.9% +/- 5.6% higher pressure in the combination device compared with the pressure-relief walker alone (mean +/- SD, 258.0 +/- 69.7 versus 235.7 +/- 66.1 kPa). This difference was only 2% of the initial barefoot pressure imparted to the wound. A modified negative pressure dressing coupled with a robust removable cast walker may not impart undue additional stress to the plantar aspect of the foot and may allow patients to retain some degree of freedom (and a potentially reduced length of hospital stay) while still allowing for the beneficial effects of negative pressure wound therapy and sufficient off-loading.

Bandages↗

Treatment of Freiberg's infraction with the titanium hemi-implant.

Freiberg's infraction is a relatively rare disease for which there is currently no consensus regarding surgical management. We present a case study describing a surgical procedure that uses a novel metatarsophalangeal hemi-implant. This procedure does not alter the metatarsal parabola, and it allows for other surgical procedures to be performed in the future.

Adult↗

Cooling the foot to prevent diabetic foot wounds: a proof-of-concept trial.

The etiology of neuropathic diabetic foot wounds can be summarized by the following formula: pressure x cycles of repetitive stress = ulceration. The final pathway to ulceration consists of an inflammatory response, leading to tissue breakdown. Mitigation of this response might reduce the risk of ulceration. This proof-of-concept trial evaluates whether simple cooling of the foot can safely reduce the time to thermal equilibrium after activity. After a 15-min brisk walk, the six nondiabetic volunteers enrolled were randomly assigned to receive either air cooling or a 10-min 55 degrees F cool water bath followed by air cooling. The process was then repeated with the intervention reversed, allowing subjects to serve as their own controls. There was a rise in mean +/- SD skin temperature after 15 min of activity versus preactivity levels (87.8 degrees +/- 3.9 degrees versus 79 degrees +/- 2.2 degrees F; P = .0001). Water cooling immediately brought the foot to a point cooler than preactivity levels for all subjects, whereas air cooling required an average of nearly 17 min to do so. Ten minutes of cooling required a mean +/- SD of 26.2 +/- 5.9 min to warm to preactivity levels. No adverse effects resulted from the intervention. We conclude that cooling the foot may be a safe and effective method of reducing inflammation and may serve as a prophylactic or interventional tool to reduce skin breakdown risk.

Adult↗

Maggot therapy in "lower-extremity hospice" wound care: fewer amputations and more antibiotic-free days.

We sought to assess, in a case-control model, the potential efficacy of maggot debridement therapy in 60 nonambulatory patients (mean +/- SD age, 72.2 +/- 6.8 years) with neuroischemic diabetic foot wounds (University of Texas grade C or D wounds below the malleoli) and peripheral vascular disease. Twenty-seven of these patients (45%) healed during 6 months of review. There was no significant difference in the proportion of patients healing in the maggot debridement therapy versus control group (57% versus 33%). Of patients who healed, time to healing was significantly shorter in the maggot therapy than in the control group (18.5 +/- 4.8 versus 22.4 +/- 4.4 weeks). Approximately one in five patients (22%) underwent a high-level (above-the-foot) amputation. Patients in the control group were three times as likely to undergo amputation (33% versus 10%). Although there was no significant difference in infection prevalence in patients undergoing maggot therapy versus controls (80% versus 60%), there were significantly more antibiotic-free days during follow-up in patients who received maggot therapy (126.8 +/- 30.3 versus 81.9 +/- 42.1 days). Maggot debridement therapy reduces short-term morbidity in nonambulatory patients with diabetic foot wounds.

Aged↗

Efficacy of fifth metatarsal head resection for treatment of chronic diabetic foot ulceration.

This study compares the potential benefit of fifth metatarsal head resection versus standard conservative treatment of plantar ulcerations in people with diabetes mellitus. Using a retrospective cohort model, we abstracted data from 40 patients (22 cases and 18 controls) treated for uninfected, nonischemic diabetic foot wounds beneath the fifth metatarsal head. There were no significant differences in sex, age, duration of diabetes mellitus, or degree of glucose control between cases and controls. Patients who underwent a fifth metatarsal head resection healed significantly faster (mean +/- SD, 5.8 +/- 2.9 versus 8.7 +/- 4.3 weeks). Patients were much less likely to reulcerate during the period of evaluation in the surgical group (4.5% versus 27.8%). The results of this study suggest that fifth metatarsal head resection is a potentially effective treatment in patients at high risk of ulceration and reulceration.

Aged↗

Do US veterans wear appropriately sized shoes?: the Veterans Affairs shoe size selection study.

Poorly fitting footwear has frequently been cited as an etiologic factor in the pathway to diabetic foot ulceration. However, we are unaware of any reports in the medical literature specifically measuring shoe size versus foot size in this high-risk population. We assessed the prevalence of poorly fitting footwear in individuals with and without diabetic foot ulceration. We evaluated the shoe size of 440 consecutive patients (94.1% male; mean +/- SD age, 67.2 +/- 12.5 years) presenting to an interdisciplinary teaching clinic. Of this population, 58.4% were diagnosed as having diabetes, and 6.8% had active diabetic foot ulceration. Only 25.5% of the patients were wearing appropriately sized shoes. Individuals with diabetic foot ulceration were 5.1 times more likely to have poorly fitting shoes than those without a wound (93.3% versus 73.2%; odds ratio [OR], 5.1; 95% confidence interval [CI], 1.2-21.9; P = .02). This association was also evident when assessing only the 32.3% of the total population with diabetes and loss of protective sensation (93.3% versus 75.0%; OR, 4.8; 95% CI, 1.1-20.9; P = .04). Poorly fitting shoes seem to be more prevalent in people with diabetic foot wounds than in those without wounds with or without peripheral neuropathy. This implies that appropriate meticulous screening for shoe-foot mismatches may be useful in reducing the risk of lower-extremity ulceration.

Aged↗

Verrucous hyperplasia: a common and problematic finding in the high-risk diabetic foot.

Although verrucous hyperplasia may be common in high-risk insensitive feet, the literature contains little discussion on this topic. Treatment of verrucous hyperplasia is aimed primarily at reducing the causative forces. In cases that result from edema, external compression has proved to be adequate. If verrucous hyperplasia on the foot results from frictional forces, then shoe modifications with proper fit, accommodative liners, or fillers in the case of amputation are necessary. In recalcitrant cases, excision of the affected tissue with local soft-tissue or graft coverage has been successful. We describe a 56-year-old man with verrucous hyperplasia.

Amputation, Surgical↗

Use of subatmospheric (VAC) therapy to improve bioengineered tissue grafting in diabetic foot wounds.

The use of bioengineered tissue and topical subatmospheric pressure therapy have both been widely accepted as adjunctive therapies for the treatment of noninfected, nonischemic diabetic foot wounds. This article describes a temporally overlapping method of care that includes a period of simultaneous application of bioengineered tissue (Apligraf, Novartis Pharmaceuticals Corp, East Hanover, New Jersey) and subatmospheric pressure therapy delivered through the VAC (Vacuum Assisted Closure) system (KCI, Inc, San Antonio, Texas). Future descriptive and analytic works may test the hypothesis that combined therapies used at different and often overlapping periods during the wound-healing cycle may be more effective than a single modality.

Bandages↗

Maggot debridement therapy: a primer.

Treatment of chronic wounds of the lower extremity requires a systematic, multidisciplinary approach as well as flexibility in order to achieve acceptable, consistent short-term and long-term results. Maggots, once considered an obsolete therapeutic modality, can be a useful addition to the armamentarium of the foot and ankle specialist. This article describes the use of maggot debridement therapy for intractable wounds of the lower extremity.

Animals↗

How and why to surgically debride neuropathic diabetic foot wounds.

Wound debridement, when systematically performed, may be as important as off-loading in reducing the prevalence of chronic inflammatory by-products in a wound and thus in converting a chronic wound into an acute one. Although it has been suggested that aggressive surgical debridement of wounds may be beneficial, there have been few, if any, technical descriptions of this aspect of therapy. It is therefore the purpose of this article to describe the general principles, process, and technique of outpatient surgical debridement of noninfected, nonischemic neuropathic diabetic foot wounds performed at the authors' institutions. The authors hope to foster further discussion leading to improvement in the process and the prevalence of such debridement.

Debridement↗