High failure rates of the Spectron EF stem at a minimum of 10 year's follow-up.

We prospectively followed 112 hips, undergoing THA with a Spectron EF stem. At mean follow-up of 11.2years, 21 patients had died. We obtained radiological follow-up in 99% and clinical follow-up in 100% of the surviving 91 hips. Fifty-four percent demonstrated osteolysis in at least one Gruen zone. Twenty-two hips required revision for all causes, with a further five stems radiologically loose. With endpoint being stem revision for aseptic loosening or radiological failure, survivorship at 11years was 0.783. We believe the addition of a rougher surface finish has contributed to the high levels of osteolysis and stem failure seen with the Spectron EF.

Revision of failed unicompartmental knee replacement to total knee replacement.

Recent reports suggest good outcome results following unicompartmental knee replacement (UKR). However, a number of authors have commented on the problem of osseous defects requiring technically difficult revision surgery. We reviewed clinical outcomes following revision total knee replacement (TKR) for failed UKR and analysed the reasons for failure and the technical aspects of the revision surgery. Between 2001 and 2010 our institute performed 132 UKR's out of which 33 required revision to TKR during a period 6 years. Demographics, details and indications for primary and revision surgery, the revised prosthesis including augments, technical difficulties and complications were noted. Patient outcome assessment was based on the Oxford knee score (OKS). Survival analysis for the UKR prosthesis was calculated using Kaplan-Meier Survival curves. Reasons for revision included aseptic loosening, persistent pain, dislocated meniscus, mal-alignment and other compartment osteoarthritis. Median time to revision was 19 months (range 2-159). Using revision as the end-point the survival proportion at 5-years was 69%. 18 revisions required additional intra-operative constructs including stemmed implants, wedge augmentation or bone graft. The mean 1 year post-operative OKS was 29 compared to 39 for primary TKR during the same period (p<0.001). Aseptic loosening was the commonest mode of failure. UKR survivorship at a non-specialist institute is considerably lower than at originating centres. Two thirds of the revisions were technically difficult and required additional constructs. The clinical outcome after revision surgery was inferior to that of primary TKR. The role of UKR needs to be more clearly defined.

Evaluation of contraindicated drug-drug interaction alerts in a hospital setting.

BACKGROUND: Risks associated with contraindicated drug-drug interaction alerts (CDDIAs) should always outweigh benefits. Misclassified CDDIAs should be eliminated. OBJECTIVE: To review CDDIAs and determine if they are contraindicated according to Food and Drug Administration-approved product labeling and if there are circumstances in which contraindicated interactions are acceptable. METHODS: A cross-sectional observational and quality improvement study was conducted over two 1-year periods. The 20 most common CDDIAs from May 2007 to May 2008 and all CDDIAs from April 2008 to April 2009 were collected at a large teaching hospital. Horizon Meds Manager used First DataBank as the knowledge base for decision support. Interactions were deemed truly contraindicated if listed in the contraindications section of the labeling of at least one of the interacting drugs. Alerts were grouped by drug and pharmacologic class to evaluate the evidence supporting the relevance of these interactions. An expert panel determined when an alert was misclassified. A medical advisory committee determined whether a contraindicated drug-drug combination was acceptable. RESULTS: Twelve (60%) of the most common 20 contraindicated interaction pairs from 2007 to 2008 were inappropriately classified. Half of the alerts were not truly contraindicated. The 8 truly contraindicated drug-drug pairs were ketorolac and other nonsteroidal antiinflammatory drugs or oral solid potassium products and anticholinergics. Half of these interactions were subsequently deemed acceptable under specific circumstances. Similar results were found in the second year, with only 55.1% of all CDDIAs being truly contraindicated despite eliminating some of the alerts that were misclassified in the first year. Nearly three fourths of legitimate CDDIAs were deemed acceptable under specific circumstances. CONCLUSIONS: Most contraindicated drug-drug interaction alerts from a commercial knowledge base were inappropriately categorized and could be downgraded. Some contraindicated drug combinations are permissible under specific circumstances. Alerts suggesting that certain drugs should never be used together, but their use together is sometimes acceptable, contribute to alert fatigue.

Changing the Management from Olecranon Screw Traction to Percutaneous Wiring for Displaced Supracondylar Fractures of the Humerus in Children. A Justified Decision?

BACKGROUND AND PURPOSE: In this institution, the management of displaced (Gartland III) supracondylar fractures in children was changed from overhead olecranon screw traction to manipulation and percutaneous wiring in 1996. The purpose of this study was to compare the two methods of treatment and observe whether the decision to change management was justified. METHODS: A retrospective study of two cohorts; 151 patients between 1986 and 1996 treated with olecranon screw traction and 92 patients between 1996 and 2002 treated with percutaneous wiring. Both sets of patients were followed up clinically and radiologically until the child could demonstrate a satisfactory range of movement and the fracture had united. RESULTS: There were no differences in the clinical outcomes between the two groups. The main difference between the groups was in length of stay, which was a median of 1 day in the wired group and 14 days in the traction group. CONCLUSION: Outcomes achieved from percutaneous wiring of displaced supracondylar fractures are similar to those from olecranon screw traction. The advantage of percutaneous wiring to both patient and provider is the reduced hospital stay. The decision to change management therefore appears to be justified. However, percutaneous wiring is generally a technically more demanding procedure and olecranon screw traction should remain a possible treatment option for the management of this injury.

Molecular structures of Se(SCH3)2 and Te(SCH3)2 using gas-phase electron diffraction and ab initio and DFT geometry optimisations.

The molecular structures of Se(SCH(3))(2) and Te(SCH(3))(2) were investigated using gas-phase electron diffraction (GED) and ab initio and DFT geometry optimisations. While parameters involving H atoms were refined using flexible restraints according to the SARACEN method, parameters that depended only on heavy atoms could be refined without restraints. The GED-determined geometric parameters (r(h1)) are: rSe-S 219.1(1), rS-C 183.2(1), rC-H 109.6(4) pm; angleS-Se-S 102.9(3), angleSe-S-C 100.6(2), angleS-C-H (mean) 107.4(5), phiS-Se-S-C 87.9(20), phiSe-S-C-H 178.8(19) degrees for Se(SCH(3))(2), and rTe-S 238.1(2), rS-C 184.1(3), rC-H 110.0(6) pm; angleS-Te-S 98.9(6), angleTe-S-C 99.7(4), angleS-C-H (mean) 109.2(9), phiS-Te-S-C 73.0(48), phiTe-S-C-H 180.1(19) degrees for Te(SCH(3))(2). Ab initio and DFT calculations were performed at the HF, MP2 and B3LYP levels, employing either full-electron basis sets [3-21G(d) or 6-31G(d)] or an effective core potential with a valence basis set [LanL2DZ(d)]. The best fit to the GED structures was achieved at the MP2 level. Differences between GED and MP2 results for rS-C and angleS-Te-S were explained by the thermal population of excited vibrational states under the experimental conditions. All theoretical models agreed that each compound exists as two stable conformers, one in which the methyl groups are on the same side (g(+)g(-) conformer) and one in which they are on different sides (g(+)g(+) conformer) of the S-Y-S plane (Y = Se, Te). The conformational composition under the experimental conditions could not be resolved from the GED data. Despite GED R-factors and ab initio and DFT energies favouring the g(+)g(+) conformer, it is likely that both conformers are present, for Se(SCH(3))(2) as well as for Te(SCH(3))(2).