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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 degrees F (>2.2 degrees 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. [ABSTRACT FROM AUTHOR]

This investigation evaluates the effects of diabetes on the mechanical properties of human bone, specifically, the tibia. Seven diabetic and seven nondiabetic human (male) cadaveric distal tibiae were used in this study. The average age of the diabetic cadaveric samples was 51 years (range, 46-61 years), and the average age of the nondiabetic cadaveric samples was 75 years (range, 67-85 years). Three-point bending tests for strength and stiffness were performed on a small sample of each distal tibia. Each specimen was loaded at a constant rate until failure. From the recorded curve of load versus displacement, the ultimate and yield strength of bone and the bending modulus of bone were calculated. The diabetic samples were generally weaker than the older, nondiabetic samples, but no statistically significant differences were found in the elastic modulus (P = .29), yield strength (P = .90), ultimate strength (P = .46), and fracture toughness (P = .78), leading to speculation that diabetes has an effect similar to that of aging on the musculoskeletal system.

Objective: To evaluate the effectiveness of at-home infrared temperature monitoring as a preventative tool in individuals at high risk for diabetes-related lower-extremity ulceration and amputation., Research Design and Methods: Eighty-five patients who fit diabetic foot risk category 2 or 3 (neuropathy and foot deformity or previous history of ulceration or partial foot amputation) were randomized into a standard therapy group (n = 41) or an enhanced therapy group (n = 44). Standard therapy consisted of therapeutic footwear, diabetic foot education, and regular foot evaluation by a podiatrist. Enhanced therapy included the addition of a handheld infrared skin thermometer to measure temperatures on the sole of the foot in the morning and evening. Elevated temperatures (>4 degrees F compared with the opposite foot) were considered to be "at risk" of ulceration due to inflammation at the site of measurement. When foot temperatures were elevated, subjects were instructed to reduce their activity and contact the study nurse. Study subjects were followed for 6 months., Results: The enhanced therapy group had significantly fewer diabetic foot complications (enhanced therapy group 2% vs. standard therapy group 20%, P = 0.01, odds ratio 10.3, 95% CI 1.2-85.3). There were seven ulcers and two Charcot fractures among standard therapy patients and one ulcer in the enhanced therapy group., Conclusions: These results suggest that at-home patient self-monitoring with daily foot temperatures may be an effective adjunctive tool to prevent foot complications in individuals at high risk for lower-extremity ulceration and amputation.

The objective of this review is to provide basic information pertaining to biomechanical aspects of bone as they relate to tissue engineering. The review is written for the general tissue engineering reader, who may not have a biomechanical engineering background. To this end, biomechanical characteristics and properties of normal and repair cortical and cancellous bone are presented. Also, this chapter intends to describe basic structure-function relationships of these two types of bone. Special emphasis is placed on salient classical and modern testing methods, with both material and structural properties described.

Reproducible fractures of the posterior wall of the acetabulum were created in 10 paired hemipelves from fresh human cadavers. Under anterior-to-posterior loading by a Materials Testing System machine, the load to failure of fixation of the acetabular fractures treated with steel pelvic reconstruction plates and steel screws was significantly higher than that of fixation with titanium ribbons and titanium screws. Forces as little as 725 newtons applied directly to the fragment caused fixation failure; even the most secure form of fixation failed when a relatively small force of 2,123 newtons was applied. These results emphasize the importance of appropriate postoperative measures, such as limitation of hip flexion and restricted weightbearing, to minimize the force directed against the posterior wall until the fracture has healed. Secure fixation of fractures of the posterior wall of the acetabulum is critical, since loss of fixation results in instability and joint incongruity, which limit the options for reconstruction.

Adhesion of cells to biomaterials or to components of the extracellular matrix is fundamental in many tissue engineering and biotechnological processes, as well as in normal development and tissue maintenance. Many cells on adhesive molecules will spread and form an organized actin cytoskeleton and complex transmembrane signaling regions called focal adhesions. Focal adhesions appear to function as both signaling and stabilizing components of normal adherent cell activity. To better understand adhesion formations between cells and their underlying substrata, we have designed, developed, and utilized a novel 'cytodetachment' methodology to quantify the force required to displace attached cells. We allowed bovine articular chondrocytes to attach and spread on a substratum of either fibronectin, bovine serum albumin, or standard microscope glass. The cytodetacher was then employed to displace the cells from the substratum. Our results demonstrate that a significantly greater force is required to detach cells from fibronectin versus the two other substrata, suggesting that a cell's actin cytoskeleton and perhaps focal adhesions contribute significantly to its mechanical adhesiveness. The cytodetacher allows us to directly measure the force required for cell detachment from a substratum and to indirectly determine the ability of different substrata to support cell adhesion.

The objective of this study was to provide a map of cartilage biomechanical properties, thickness, and histomorphometric characteristics in the human, cadaveric first metatarsophangeal joint, to determine if normal articular cartilage was predisposed topographically to biomechanical mismatches in articulating surfaces. Cartilage intrinsic material properties and thickness were obtained from seven pairs of human, freshly frozen, cadaveric, metatarsophalangeal joints using an automated creep indentation apparatus under conditions of biphasic creep. Eight sites were tested: four on the metatarsal head, two on the proximal phalanx base, and one on each sesamoid bone to obtain the aggregate modulus, Poisson's ratio, permeability, shear modulus, and thickness. Cartilage in the lateral phalanx site of the left metatarsal head had the largest aggregate modulus (1.34 MPa), whereas the softest tissue was found in the right medial sesamoid (0.63 MPa). The medial phalanx region of the right joint was the most permeable (4.56 x 10(-15) meter4/Newton-second), whereas the medial sesamoid articulation of the metatarsal head of the left joint was the least permeable (1.26 x 10(-15) meter4/Newton-second). Material properties and thickness are indicative of the tissue's functional environment. The lack of mismatches in cartilage biomechanical properties of the articulating surfaces found in this study may be supportive of clinical observations that early degenerative changes, in the absence of traumatic events, do not occur at the selected test sites in the human first metatarsophalangeal joint.

Intrinsic material properties and histomorphometry of freshly frozen, human cadaveric cartilage from the second metatarsal intermediate cuneiform (SMIC) articulation were obtained to provide biomechanical mapping of the surfaces. The biphasic creep indentation methodology and an automated creep indentation apparatus were used to measure aggregate modulus, Poisson's ratio, permeability, shear modulus, and thickness. Biomechanical experiments were performed on four sites of the SMIC joint in 14 specimens (seven pairs): two sites in the second metatarsal base and two sites in the intermediate cuneiform head. Results of the study indicate that no significant variations exist in the biomechanical comparisons between specific articulations, gross articulations, and left and right joints. For example, cartilage from the second metatarsal base and intermediate cuneiform head had an aggregate modulus of 0.99 MPa and 1.05 MPa, respectively. The Poisson's ratio and permeability of all test sites grouped together were found to be 0.08 and 3.05 x 10(-15) m4/N.s, respectively. Cartilage thickness was measured at 0.61 mm. This biomechanical study suggests that similarities in cartilage properties may be beneficial in preventing the human SMIC articulation from developing early degenerative changes. Histological evaluation demonstrated that SMIC cartilage exhibits structural characteristics (such as the absence of chondrocyte columnar arrangement in the deep zone) which may be typical of cartilage that does not experience habitually high compressive stresses. This knowledge could aid surgeons in generating a deeper perspective of the relationship between clinical pathologies of articular cartilage and intrinsic biomechanical etiologies of degenerative joint diseases.