Biomechanical Comparison of Fixed- versus Variable-Angle Locking Screws for Distal Humerus Comminuted Fractures

BACKGROUND: To compare the stability of fixed- versus variable-angle locking constructs for the comminuted distal humerus fracture (AO/OTA 13-A3). METHODS: Eight pairs of complete humeri harvested from eight fresh frozen cadavers were used for the study. We fixed the intact humeri using 2.7-mm/3.5-mm locking VA-LCP stainless steel distal humerus posterolateral (nine-hole) and medial (seven-hole) plates. An oscillating saw was used to cut a 1-cm gap above the olecranon fossa. The specimens were loaded in axial mode with the rate of 1 mm per 10 seconds to failure, and stress-strain curves were compared in each pair. The mode of failure was recorded as well as the load needed for 2- and 4-mm displacement at the lateral end of the gap. RESULTS: The stiffness of the constructs, based on the slope of the stress-strain curve, did not show any difference between the fixed- versus variable-angle constructs. Likewise, there was no difference between the force needed for 2- or 4-mm displacement at the lateral gap between the fixed- and variable-angle constructs. The mode of failure was bending of both plates in all specimens and screw pull-out in four specimen pairs in addition to the plate bending. CONCLUSIONS: Our results did not show any difference in the biomechanical stability of the fixed- versus variable-angle constructs. There was not any screw breakage or failure of the plate-screw interface.

Association of smoking with high-grade transitional cell carcinoma of the urinary bladder

Accurate staging and grading of bladder neoplasms, which are the most important guides for the treatment of transitional cell carcinoma [TCC], depend seriously on the interpretation of tumor biopsies by pathologists and are largely subject to inter- and intrapathologist variations. Therefore, it appears that clinicians should have additional guides to appropriately diagnose and treat high-risk patients. We evaluated the association of the grade of TCC of the urinary bladder with four patient's variables, i.e., age, gender, cigarette smoking, and opium consumption, to find out if any of them could serve as a guide for clinicians. A retrospective study was performed on 255 individuals in whom TCC was diagnosed. Correlations between the grade of TCC and clinical features were determined. Age was not correlated with tumor grade [P = 0.59], but cigarette smoking [P = 0.032] and male gender [P = 0.029] showed positive associations with higher grades. The association between male gender and higher grades is probably due to the higher incidence of cigarette smoking among men [P < 0.001], making this correlation spurious. Because opium consumption had a significant correlation with smoking [P < 0.001], its correlation [P = 0.012] with high grades of TCC could not be validated as accurate. Cigarette smokers and males [according to a high prevalence of cigarette smoking among males] are more prone to develop high grades of urinary bladder TCC. In these high-risk groups, there should be a low threshold for the review of pathologic material if the primary pathological examination shows a low-grade carcinoma, for adjuvant treatment [intravesical therapy], and for careful follow-up after the treatment-especially when pathological differentiation between the grades is difficult