David G. Armstrong

The natural history of great toe amputations

The purpose of this study is to report the prevalence of reamputation following resection of the great toe and first ray in adults with diabetes. We abstracted the medical records of 90 diabetic great-toe and first-ray amputees admitted between 1981 and 1991. The most common etiologies of initial amputations were ulcer with soft tissue infection (39%), ulcer with osteomyelitis (32%), and puncture wounds (12%). Sixty percent of all patients had a second amputation, 21% had a third, and 7% had a fourth. Fifteen percent of the patients who had a second amputation had it contralaterally. Seventeen percent subsequently underwent a below-knee amputation and 11% had a Transmetatarsal amputation on the same extremity, 3% had a below-knee amputation, and 2% a transmetatarsal amputation contralaterally. The mean time from the first to the second amputation was approximately 10 months. The results of this study suggest that a large proportion of patients undergoing an amputation at the level of the great toe or first ray have subsequent amputations in the first year following the initial procedure. Additionally, it appears that the contralateral foot may be at significant risk for distal amputation following resection of the hallux or first day.

The natural history of acute Charcot's arthropathy in a diabetic foot specialty clinic

The aim of this longitudinal study was to report on the clinical characteristics and treatment course of acute Charcots arthropathy at a tertiary care diabetic foot clinic. Fifty-five diabetic subjects, with a mean age of 58.6 +/- 8.5 years, were studied. All patients were treated with serial total contact casting until quiescence. Following casting and before transfer to prescription footwear, patients were eased into unprotected weightbearing via a removable cast walker. This cohort was followed for their entire treatment course and for a mean 92.6 +/- 33.7 weeks following return to shoes. Pain was the most frequent presenting complaint in these otherwise insensate patients (76%). The mean duration of casting was 18.5 +/- 10.6 weeks. Patients returned to footwear in a mean 28.3 +/- 14.5 weeks. Nine per cent of the population had bilateral arthropathy. These subjects were casted significantly longer than the unilateral group (p < 0.02). Surgery was performed on 25 % of patients, with approximately two-thirds of these procedures involving plantar exostectomies and one-third fusions of affected joints. Patients receiving surgery remained casted significantly longer than non-surgical patients (p < 0.05). Additionally, men were casted longer than women (p < 0.008). Acute Charcots arthropathy requires prompt, uncompromising reduction in weightbearing stress. Our data show that the ambulatory total contact cast is very effective for this. Regardless of the specific treatment method instituted, it is imperative that appropriate and aggressive treatment be undertaken immediately following diagnosis to help prevent progression to a profoundly debilitating, limb-threatening deformity.

Value of white blood cell count with differential in the acute diabetic foot infection.

The authors reviewed the admission leukocyte indices of 338 consecutive admissions (203 males, 135 females, mean age of 60.2 +/- 12.9 years) with a primary diagnosis of diabetic foot infection in a multicenter retrospective study. The mean white blood cell count on admission for all subjects studied was calculated at 11.9 +/- 5.4 x 103 cells/mm3. Of all white blood cell counts secured for patients admitted with a diabetic foot infection, 56% (189 out of 338) were within normal limits. The average automated polymorphonuclear leukocyte percentage was calculated at 71.4 +/- 11.1% (normal range 40% to 80%). Normal polymorphonuclear leukocyte values were present in 83.7% of subjects. The authors stress that the diagnosis of a diabetic pedal infection is made primarily on the basis of clinical signs and symptoms, and that a normal white cell count and white cell differential should not deter the physician from taking appropriate action to mitigate the propagation of a potentially limb-threatening pedal infection.

Mortality following lower extremity amputation in minorities with diabetes mellitus

The aim of this study was to identify the age adjusted and level specific mortality rate in African-Americans, Hispanics and non-Hispanic whites (NHW) during the perioperative period following a lower extremity amputation. We identified amputation data obtained from the Office of Statewide Planning and Development in California for 1991 from ICD-9-CM codes 84.11-84.18 and diabetes mellitus from any 250 related code. Amputations were categorized as foot (84.11-84.12), leg (84.13-84.16) or thigh (84.17-84.18). Death was coded under discharge status. Age adjusted and level specific mortality rates per 1000 amputees were calculated for each race/ethnic group. The age adjusted mortality was highest for African-Americans (41.39) compared to Hispanics (19.69) and NHWs (34.98). Mortality was consistently more frequent for proximal amputations. We conclude that mortality rates for persons with diabetes hospitalized for an amputation varied by race, gender and level of amputation. Higher prevalence or severity of risk factors may explain the excess mortality observed in African-Americans.

Outcomes of transmetatarsal amputations in patients with diabetes mellitus

The purpose of this study was to report on the long-term outcomes of transmetatarsal amputations secondary to sequelae of diabetes mellitus. We abstracted data from 35 diabetic patients receiving a transmetatarsal amputation over a 6-month period in 1992. Patients were followed for a mean 15.1 +/- 10.1 months. The results indicated that the most predictive factor determining higher level amputation (transfemoral or transtibial) appeared to be the actual indication for surgery (90.0% ischemia versus 4.0% infection, chi 2 = 21.7, odds ratio = 220, 95% confidence interval = 12.5-3885.0, p < 0.05). Those with a diagnosis of infection without underlying critical ischemia were significantly more likely to heal at the level of the foot. While all patients presenting for care had dramatically impaired nutritional values and elevated glucose, albumin was significantly lower in subjects receiving a transfemoral or transtibial revision. High-level amputees were also significantly less likely to have been prescribed depth-inlay shoe gear prior to their amputation (48.0% vs. 10.0%, chi 2 = 4.4, odds ratio = 8.3, 95% confidence interval = 1.0-75.7, p < 0.05). Those with a diagnosis of infection without underlying critical ischemia were significantly more likely to heal at the level of the foot. Though revision rates are high, the success rates are also high if that is defined as retaining the foot and providing a prosthesis-free normal gait.

Total contact casts and removable cast walkers. Mitigation of plantar heel pressure.

The purpose of this study was to compare the ability of various modalities to reduce pressure in the plantar heel. Twenty-five patients with grade 1A plantar foot ulcerations were evaluated; a repeat measures design comparing plantar pressure was used to evaluate the total contact cast, the Aircast pneumatic walker, the DH pressure relief walker, and depth-inlay shoes. The total contact cast reduced pressure significantly better than the other modalities; however, its pressure reduction was only 33% less than a baseline sneaker. All other modalities reduced significantly more pressure than the depth-inlay shoe. The DH walker had a significantly lower pressure-time integral than other modalities. These data indicate that, while the total contact cast appears to be effective compared with other modalities, the role that limitation of transverse motion of the fat pad on compression at heel strike has yet to be fully explained.

Limb salvage with Chopart's amputation and tendon balancing

For several decades, Choparts 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. This concept dictates that the shorter the midfoot-level amputation, the more likely the patient is to develop an equinovarus deformity, thus exposing the fifth metatarsal base and cuboid to weightbearing stress and a high risk of ulceration. Choparts amputation, in eliminating the cuboid, often obviates the potential varus deformity and thus can have a more acceptable long-term result.

Evaluation and treatment of the infected foot in a community teaching hospital

More inpatient hospital days are used for the care of diabetic foot infection than for any other diabetic sequela. Both the number of lower extremity amputations and the overall treatment cost of treating diabetic infections may be reduced by using a team approach in the care of the infected diabetic pedal wound. The authors propose an evaluation and treatment protocol of infected pedal ulcerations in an urban, community teaching institution when admitted to an established, multidisciplinary diabetic foot care team. The hospital course of 111 patients admitted with a primary diagnosis of infected pedal ulceration are retrospectively reviewed. Results revealed an average-length hospital stay of 7.4 days with a 96% limb-salvage rate. The authors suggest that in the treatment of the infected pedal wound, a diabetic foot care team with a well developed treatment protocol may yield a consistently favorable outcome and a cost-effective hospital course.

Emergence of non-group A streptococcal necrotizing diabetic foot infections

Recently the authors have noted a disturbing trend toward an increased incidence of necrotizing infections caused by non-group A streptococcal species. This article describes the typical clinical course of such an infection. Prompt surgical intervention, coupled with an antibiotic regimen aimed at mitigating exotoxin release, may be both limb- and life-preserving.

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. In each case, a rapidly spreading cellulitis followed trauma to the foot, which necessitated emergent incision and drainage. Five patients required extensive fascial and skin debridement because of soft-tissue destruction, and two patients needed below-the-knee amputation because of uncontrolled infection. These cases suggest that non-group A streptococci, like group A streptococci, can cause serious skin and soft-tissue infections in patients with diabetes that may require aggressive surgical debridement despite appropriate antibiotic therapy.