Biomedical subjects

Kevin J Deluzio

Publications and source records attributed to Kevin J Deluzio.

5 recordsLinked to original sources

PubMed2006

Knee biomechanics of moderate OA patients measured during gait at a self-selected and fast walking speed.

Osteoarthritis (OA) is a chronic disorder resulting in degenerative changes to the knee joint. Three-dimensional gait analysis provides a unique method of measuring knee dynamics during activities of daily living such as walking. The purpose of this study was to identify biomechanical features characterizing the gait of patients with mild-to-moderate knee OA and to determine if the biomechanical differences become more pronounced as the locomotor system is stressed by walking faster. Principal component analysis was used to compare the gait patterns of a moderate knee OA group (n=41) and a control group (n=43). The subjects walked at their self-selected speed as well as at 150% of that speed. The two subject groups did not differ in knee joint angles, stride length, and stride time or walking speed. Differences in the magnitude and shape of the knee joint moment waveforms were found between the two groups. The OA group had larger adduction moment magnitudes during stance and this higher magnitude was sustained for a longer portion of the gait cycle. The OA group also had a reduced flexion moment and a reduced external rotation moment during early stance. Increasing speed was associated with an increase in the magnitude of all joint moments. The fast walks did not, however, increase or bring out any biomechanical differences between the OA and control groups that did not exist at the self-selected walks.

Biomechanical Phenomena↗

PubMed2006

Principal component analysis of lifting waveforms.

BACKGROUND: One limiting factor in lifting research design has been the inability to effectively analyze waveform data, especially when differences in body mass, height, and load magnitude influence the derived kinetic variables. The purpose of this study was to demonstrate the sensitivity of principal component analysis to quantify clinically relevant differences in kinetic lifting waveforms over three load magnitudes and between two separate populations. METHODS: Principal component analysis was applied to five kinetic lifting waveforms. The derived principal component scores were used as the dependent measures in a two-way (clinical status x load magnitude) MANOVA. FINDINGS: Significant low back pain group differences (P<0.05) were found for three of the principal component scores on extension moment generation in the sacral and thoracic regions and for trunk compression. Significant differences were found for each variable with respect to the magnitude across the entire lift time between the three load conditions, as well as four significant differences related to inferred mechanical changes that resulted from lifting increasingly heavier loads. INTERPRETATION: Principal component analysis of kinetic lifting waveforms was shown to be insensitive to a confounding factor of different load magnitudes when attempting to identify previously determined clinically relevant differences in the waveform trajectories. The analysis was able to partition the variability attributed to the direct influence of different external load magnitudes, versus those differences in spinal loading that arose from the variations in the lifting mechanics of increasing loads. The technique could be beneficial for other kinetic analyses where confounding magnitude modifiers like body size are present.

Adult↗

PubMed2005

Differentiating lifting technique between those who develop low back pain and those who do not.

BACKGROUND: No research to date has been able to discriminate differences in lifting technique for healthy individuals who eventually develop low back pain compared to those that do not while employed in a manual materials handling industry. The purpose of this study was to demonstrate the ability of principal component analysis to identify differences in lifting technique. METHODS: Principal component analysis was applied to sixteen kinematic and kinetic waveforms describing the two-dimensional motion of the trunk and load. The principal component scores for each variable were used as the dependent measures in a one-way ANOVA to determine group differences. FINDINGS: Significant group differences (P<0.05) were found for five of the principal component scores capturing associated kinematic waveform patterns related to the control and placement of the box on the shelf, and associated kinetic waveform patterns related to the relative timing of extension moment generation in the sacral and thoracic regions. A related waveform pattern for trunk compression was also found. INTERPRETATION: Due to the coordinated movements involved in tasks such as lifting, differences among clinical populations have been difficult to demonstrate empirically. We were able to identify different characteristics in lifting kinematics and kinetics prior to the development of low back pain. Principal component analysis was able to identify important biomechanical differences where traditional analyses failed. This is the first study to identify such lifting differences prior to the development of low back pain.

Diagnosis, Computer-Assisted↗

PubMed2002

Knee and hip kinetics during normal stair climbing.

Understanding joint kinetics during activities of daily living furthers our understanding of the factors involved in joint pathology and the effects of treatment. In this study, we examined hip and knee joint kinetics during stair climbing in 35 young healthy subjects using a subject-specific knee model to estimate bone-on-bone tibiofemoral and patello-femoral joint contact forces. The net knee forces were below one body weight while the peak posterior-anterior contact force was close to one body weight. The peak distal-proximal contact force was on average 3 times body weight and could be as high as 6 times body weight. These contact forces occurred at a high degree of knee flexion where there is a smaller joint contact area resulting in high contact stresses. The peak knee adduction moment was 0.42 (0.15) Nm/kg while the flexion moment was 1.16 (0.24) Nm/kg. Similar peak moment values, but different curve profiles, were found for the hip. The hip and knee posterior-anterior shear forces and the knee flexion moment were higher during stair climbing than during level walking. The most striking difference between stair ascent and level walking was that the peak patello-femoral contact force was 8 times higher during stair ascent. These data can be used as baseline measures in pathology studies, as input to theoretical joint models, and as input to mechanical joint simulators.

Adult↗

PubMedDate not supplied

Comparative fixation of tibial plateau fractures using alpha-BSM, a calcium phosphate cement, versus cancellous bone graft.

OBJECTIVES: To compare the compressive strength of a bone substitute material (alpha-BSM) to cancellous bone when used to fill a defect void in a cadaver model of a Schatzker II split depression fracture of the lateral tibial plateau. DESIGN: Randomized, paired design. SETTING: Biomedical engineering laboratory. PATIENTS: Twenty-six human tibias were harvested from 13 cadavers. Three pairs of tibia fractured during preparation and were excluded. The remaining 10 matched pairs were randomized to fixation by using the bone substitute material or cancellous bone. INTERVENTION: A split depression fracture of the lateral tibial plateau was created in each tibia by using reproducible methods. This fracture was stabilized with a stainless steel L-plate and screws and either alpha-BSM or cancellous bone to fill the defect void. MAIN OUTCOME MEASUREMENTS: Stiffness of the elevated fragment in compression, total depression of the joint at 1000 N. RESULTS: The alpha-BSM bone substitute displayed significantly greater stiffness than cancellous bone constructs in Schatzker II split depression fractures of the lateral tibial plateau (P < 0.0001). Plateau defects displaced significantly less at 1000 N when using alpha-BSM in comparison to cancellous bone (P < 0.0001). CONCLUSIONS: In this cadaveric study, alpha-BSM is an effective bone substitute compared with cancellous bone graft for stabilizing split depression fractures of the lateral tibial plateau.

Bone Cements↗