George Constantinides

Preventing diabetic foot ulcer recurrence in high-risk patients : Use of temperature monitoring as a self-assessment tool

OBJECTIVE—The purpose of this study was to evaluate the effectiveness of a temperature monitoring instrument to reduce the incidence of foot ulcers in individuals with diabetes who have a high risk for lower extremity complications. RESEARCH DESIGN AND METHODS—In this physician-blinded, randomized, 15-month, multicenter trial, 173 subjects with a previous history of diabetic foot ulceration were assigned to standard therapy, structured foot examination, or enhanced therapy groups. Each group received therapeutic footwear, diabetic foot education, and regular foot care. Subjects in the structured foot examination group performed a structured foot inspection daily and recorded their findings in a logbook. If standard therapy or structured foot examinations identified any foot abnormalities, subjects were instructed to contact the study nurse immediately. Subjects in the enhanced therapy group used an infrared skin thermometer to measure temperatures on six foot sites each day. Temperature differences >4°F (>2.2°C) between left and right corresponding sites triggered patients to contact the study nurse and reduce activity until temperatures normalized. RESULTS—The enhanced therapy group had fewer foot ulcers than the standard therapy and structured foot examination groups (enhanced therapy 8.5 vs. standard therapy 29.3%, P = 0.0046 and enhanced therapy vs. structured foot examination 30.4%, P = 0.0029). Patients in the standard therapy and structured foot examination groups were 4.37 and 4.71 times more likely to develop ulcers than patients in the enhanced therapy group. CONCLUSIONS—Infrared temperature home monitoring, in serving as an “early warning sign,” appears to be a simple and useful adjunct in the prevention of diabetic foot ulcerations.

A biomechanical analysis of articular cartilage of the human elbow and a potential relationship to osteochondritis dissecans

A cadaveric study of the articular surfaces of the radiocapitellar joint was undertaken to identify a biomechanical mechanism of osteochondritis dissecans of the humeral capitellum. The articulating radial head and capitellum of fresh anatomic specimens were dissected and tested for intrinsic mechanical properties. Significant differences exist in the mechanical properties and thickness of cartilage topographically in the capitellum and radial head, and between the two surfaces. The medial portion of the radial head is the softest of all radiocapitellar osteochondral segments tested. Comparing medial to lateral sites of the capitellum, there is a trend of decreased stiffness; lateral segments are softer than medial ones. The central section of the radial head is significantly stiffer than the lateral capitellum. There is no significant difference between the stiffness of the radial head sites and the medial capitellum. The disparity in the mechanical properties of the central radial head and lateral capitellum would increase strain in the lateral capitellum. During high-valgus stress activities such as throwing, this increased strain may be a factor in the initiation and localization of the dissecans lesion observed in osteochondritis dissecans of the elbow.

Biomechanical properties of hip cartilage in experimental animal models.

The material properties of normal adult articular cartilage were determined in the femoral head and acetabulum of baboons, dogs, and bovines, and were compared with those of normal human hip cartilage. In situ creep and recovery indentation experiments were performed using an automated creep indentation apparatus. To curvefit the entire creep curve, a numerical algorithm based on biphasic finite element methods and nonlinear optimization was developed. This effort represents the first successful use of 100% of the creep indentation curve to obtain the mechanical properties of normal articular cartilage. The results show that material properties of articular cartilage exhibit significant topographical variations in the femoral head and acetabulum, and between these two bone structures. Furthermore, significant differences exist in the mechanical properties of hip cartilage among the 4 species. Specifically, in all species the smallest aggregate modulus is found in the inferior aspect of the femoral head. Among all species, human hip cartilage is the stiffest in all test sites; bovine tissue is the softest. Human tissue has the smallest Poissons ratio and permeability in all test sites. The aggregate modulus of human hip cartilage is closely resembled by that of baboon hip cartilage. Anatomically, canine and baboon hips exhibit similar characteristics to the human hip joint; the bovine hip joint is distinctly different. Based on this studys data, the baboon represents the most appropriate animal model of normal human hip articular cartilage.

Randomised clinical trial to compare total contact casts, healing sandals and a shear-reducing removable boot to heal diabetic foot ulcers

The objective of this study was to evaluate the efficacy of three off‐loading techniques to heal diabetic foot wounds: total contact casts (TCCs), healing sandals (HSs) and a removable boot with a shear‐reducing foot bed (SRB). This was a 12‐week, single‐blinded randomised clinical trial with three parallel treatment groups of adults with diabetes and a foot ulcer (n = 73). Ulcer healing was defined as full reepithelialisation with no drainage. Diabetic patients with grade UT1A or UT2A forefoot ulcers on the sole of the foot were enrolled. Patients with malignancy, immune‐compromising diseases, severe peripheral vascular disease (ankle‐brachial index < 0·60 or transcutaneous oxygen < 25 mm/Hg), alcohol or substance abuse within 6 months, untreated osteomyelitis or Charcot arthropathy with residual deformity that would not fit the HS or boot were excluded. In the intent‐to‐treat analysis, significantly higher proportion of patients were healed in the TCC group (69·6%) compared to those treated with the SRB (22·2%, P < 0·05). There was no difference in the rate of healed ulcers in the HS (44·5%) and TCC groups. Ulcers in the TCC group healed faster than those in the HS group (5·4 ± 2·9 versus 8·9 ± 3·5 weeks, P < 0·02). However, there was no difference in the time to healing in the TCC and SRB groups (6·7 ± 4·3 weeks, P = 0·28). Patients who used HS were significantly more active (4022 ± 4652 steps per day, P < 0·05) than those treated with TCCs (1447 ± 1310) or SRB (1404 ± 1234). It is concluded that patients treated with TCCs had the highest proportion of healed wounds and fastest healing time. The novel shear‐reducing walker had the lowest healing and highest rate of attrition during the study.

Shear-reducing insoles to prevent foot ulceration in high-risk diabetic patients.

PURPOSE: To enhance the learner’s competence with knowledge of the effectiveness of shear-reducing insoles for prevention of foot ulceration in patients with high-risk diabetes. TARGET AUDIENCE: This continuing education activity is intended for physicians and nurses with an interest in skin and wound care. OBJECTIVES: After participating in this educational activity, the participant should be better able to: 1. Demonstrate knowledge of foot ulceration risk, risk factors, incidence, and prevention. 2. Apply knowledge gained from reviewing this study and a literature review about the use of shear-reducing insoles to patient scenarios. ABSTRACT &NA; OBJECTIVE: The objective of this study was to evaluate the effectiveness of a shear-reducing insole compared with a standard insole design to prevent foot ulceration in high-risk patients with diabetes. RESEARCH DESIGN AND METHODS: A total of 299 patients with diabetic neuropathy and loss of protective sensation, foot deformity, or history of foot ulceration were randomized into a standard therapy group (n = 150) or a shear-reducing insole group (n = 149). Patients were evaluated for 18 months. Standard therapy group consisted of therapeutic footwear, diabetic foot education, and regular foot evaluation by a podiatrist. The shear-reducing insole group included a novel insole designed to reduce both pressure and shear on the sole of the foot. Insoles were replaced every 4 months in both groups. The primary clinical outcome was foot ulceration. The authors used Cox proportional hazards regression to evaluate time to ulceration. RESULTS: There were 2 significant factors from the Cox regression model: insole treatment and history of a foot complication. The standard therapy group was about 3.5 times more likely to develop an ulcer compared with shear-reducing insole group (hazard ratio, 3.47; 95% confidence interval, 0.96–12.67). CONCLUSIONS: These results suggest that a shear-reducing insole is more effective than traditional insoles to prevent foot ulcers in high-risk persons with diabetes.

Application of parallel processing to probabilistic fracture mechanics analysis of gas turbine disks

A parallel processing methodology is developed and applied to improve the efficiency of probabilistic fracture mechanics analyses of gas turbine disks subject to metallurgical defects. A parallel processing spatial decomposition approach using a network of workstations and personal computers is described whereby each computer analyzes a region of the disk. The individual analyses are then combined to obtain the probability of fracture of the total disk. Practical implementation issues of job scheduling and optimum file size are addressed. Numerical applications are presented that demonstrate the methodology. This capability can significantly facilitate efficient evaluations of gas turbine rotor designs.