What is the optimal salvage procedure for cut-out after surgical fixation of trochanteric fractures with the PFNA or TFN?: A multicentre study.

PURPOSE: To evaluate the outcome after different types of revision operations for blade 'cut-out' and 'cut-through' after fixation of trochanteric fractures with proximal femoral nail antirotation (PFNA) or a trochanter fixation nail (TFN). METHODS: Twenty hospitals participated in this multicentre study. A total of 4109 patients were retrospectively screened for cut-out or cut-through complications after nailing of trochanteric fractures using PFNA or TFN. Fifty-seven patients (28 with 'cut-through' and 29 with 'cut-out') were included in the study. In the 'cut-through' group, 16 patients underwent a blade exchange, six patients had a blade exchange with bone cement augmentation, and six received total hip arthroplasty (THA). In the 'cut-out' group, three patients had a blade exchange, one had a blade exchange with augmentation, three underwent re-nailing of the fracture with a new PFNA, one had a girdlestone procedure and 21 had THA procedures. RESULTS: In the 'cut-through' group, eight patients who had a blade exchanges (50%) and two patients with blade exchange and augmentation (33%) required further revision operations. THA was the definite treatment in all 6 cases. In the 'cut-out' group, two patients (66%) who had blade exchanges and two (66%) who underwent re-nailing required additional revision operations during the subsequent course. One patient (4%) who had total hip arthroplasty needed revision surgery for acetabular replacement. Overall, a total of 81 revision procedures were performed. CONCLUSION: Based on the data from this study, we recommend THA as the only valid salvage procedure for 'cut-out' and 'cut-through' of helical blades after fixation of trochanteric fractures with the PFNA and TFN.

Novel 2-(ω-phosphonooxy-2-oxaalkyl)acrylate monomers for self-etching self-priming one part adhesive.

Novel hydrolysis stable 2-(ω-phosphonooxy-2-oxaalkyl)acrylate monomers 3 with phosphoric acid moieties were synthesized by a three step synthesis via Baylis-Hillman reaction of ethyl acrylate and formaldehyde, and subsequent etherification of the obtained product with diols and phosphorylation using POCl(3). The polymerization enthalpy of 2-(ω-phosphonooxy-2-oxaalkyl)acrylates 3 as measured by DSC ranges from -29 to -53 kJ·mol(-1). The shear bond strength of adhesive compositions 4, comprising of polymerizable acids 3, ranges from 5.8 to 19.3 MPa on enamel and from 8.7 to 16.9 MPa on dentin.

N-alkyl-N-(phosphonoethyl) substituted (meth)acrylamides - new adhesive monomers for self-etching self-priming one part dental adhesive.

Novel N-alkyl-N-(phosphonoethyl) substituted mono-, bis- and tris(meth)acrylamides 3 were synthesized by two different three-step reactions and characterized by IR, (1)H NMR and (13)C NMR spectroscopy as well as refractive index and viscosity. The phosphonoethyl substituted (meth)acrylamide monomers show improved hydrolytic stability compared to carboxylic esters. The highest stability was found for the phosphonoethyl substituted acrylamide monomers. Acrylamides have a larger polymerization enthalpy ranging from -50 to -70 kJ.mol⁻¹ per double bond compared to methacrylamides which show -8.57 to -25.1 kJ.mol⁻¹ per double bond. Depending on their structure (meth)acrylamides 3 exhibit an adhesion to enamel and dentin up to 19.5 MPa. The monomer 3c shows the highest adhesion values to both substrates, namely 15.3 ± 3.4 MPa to enamel and 18.5 ± 2.3 MPa to dentin.

Li+ -induced sigma-bond metathesis: aryl for methyl exchange on boron in a methylated monocarbadodecaborate anion.

At 190 degrees C, formal sigma-bond metathesis between the B-CH3 bond in position 12 of the lithium monocarbadodecaborate derivative 1a and the C-Si(CH3)3 bond in p-bromophenyltrimethylsilane occurs and produces Si(CH3)4 and a salt of the arylated carborate anion 2, whose X-ray structure has been determined. The reaction requires the presence of active Li+ cations and does not occur with the cesium salt 1b or when 12-crown-4 is added to 1a. Possible mechanisms are briefly discussed.