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Biomedical subjects

Ioannis A Karnezis

Publications and source records attributed to Ioannis A Karnezis.

5 recordsLinked to original sources
PubMed2005

Correlation between wrist loads and the distal radius volar tilt angle.

BACKGROUND: Based on the phenomenon of bone adaptation to mechanical stimuli (Wolff's law) this study investigates a previously unreported correlation between the maximum wrist joint reaction force and the volar tilt angle of the distal radius. METHODS: Free body analysis of the sagittal-plane forces acting on the supinated distal radius during lifting and radiographic measurements in thirty normal wrists are used to analyse the correlation between the theoretically calculated maximum wrist joint reaction force and the radiographically measured volar tilt angle. FINDINGS: Non-statistically significant difference (p=0.33, 95% confidence interval -0.64 degrees to 0.22 degrees) and statistically significant correlation (R(2)=0.74, r=0.86, p<0.001) between the angle of the maximum wrist force and the volar tilt angle of the distal radius and inverse relationship between the volar tilt angle and the magnitude of the maximum wrist force (R(2)=0.71, r=-0.84, P<0.001) were found. INTERPRETATION: The radiographically measured volar tilt angle of the distal radius appears not to differ significantly from the theoretically calculated angle of the maximum wrist joint reaction force, a possible explanation for the phylogenetical development of the volar tilt angle. Also, an inverse relationship between the volar tilt angle and the magnitude of the maximum joint reaction force was observed suggesting that wrists characterized by a low volar tilt angle may be subjected during lifting activities to maximum joint reaction forces up to 50% higher than those in wrists with a high volar tilt and emphasising the importance of accurate restoration of the volar tilt during treatment of all distal radius fractures.

Adult↗
PubMed2003

Access to the medullary canal in closed antegrade femoral nailing: a technical report.

Although general recommendations exist regarding the correct placement of the skin incision and the direction of deep dissection for closed antegrade intramedullary nailing of the femur, in surgical practice simultaneously establishing the correct entry point and exact direction for insertion of the entry instrument in the lateral (sagittal) plane may be difficult. This is due to sub-optimal radiographic images in the lateral plane as a result of the overlying shadows of the pelvis, variations in the degree of rotation of the femur during patient positioning and fracture reduction manoeuvres, variations in the degree of anterior bowing of the femoral shaft and the anatomy of the greater trochanter, and deviations of the plane of deep dissection caused by the glutei muscle fibres. This may lead to the need for several attempts with increased damage to the glutei muscles, high exposure to radiation and the risk of an iatrogenic fracture. The present technical note describes a simple method for swift, easy and accurate access to the medullary canal during closed antegrade femoral nailing.

Femoral Fractures↗
PubMed2003

Secondary patellar resurfacing in total knee arthroplasty: results of multivariate analysis in two case-matched groups.

Although patellofemoral symptoms after patellar-retaining knee arthroplasty are common, no evidence has been published in the literature on the potential benefit from patellar resurfacing at a later stage. This study evaluates the effect of secondary (delayed) patellar resurfacing using comparisons between 2 case-matched groups of patients with primary and secondary patellar resurfacing. Furthermore, multivariate statistical methods were applied to study factors that may influence the final outcome. Our results suggest that although significant clinical improvement was seen after delayed patella resurfacing, the outcome of secondary patellar resurfacing is inferior to that expected for a similar group of patients with primary resurfacing. Furthermore, the timing (delay period) of the secondary resurfacing procedure appears to negatively affect the final outcome. This suggests that secondary patellar resurfacing, when indicated, should be considered at an early stage.

Aged↗
PubMed2000

Computer Modeling in Bone Research.

Computer modeling has had an undoubtedly enormous impact on the field of bone research in recent years. Development of advanced computer based models has permitted researchers to explore a vast area of musculoskeletal science from the complex biophysical stimuli at the cellular level to the mechanical behavior of heterogeneous skeletal structures. Furthermore, computer modeling has given significant impetus to the impressive progress of modern bone implant development. With recent advances in computers, faster hardware and increasingly sophisticated software, the prospects for the future of computer-based bone research appear more exciting than ever.

Journal Article↗