Age-Related Variations in Volar Cortical Angle of the Distal Radius.

Background: The ideal volar locking plate for the treatment of distal radius fracture should anatomically fit the volar surface of the distal radius. The purpose of this study was to measure the volar cortical angle (VCA) of uninjured adult distal radii to determine how well the VCA matches that of modern volar locking plates and whether variations in the VCA are related to demographic factors. Methods: A retrospective radiographic analysis of 273 uninjured adult distal radii was performed. Patients were stratified into age quintiles: less than 27 years, 27 to 43 years, 44 to 51 years, 52 to 64 years, and 65 years or older. The VCA was measured on lateral wrist radiographs, and patient demographics, including age and sex, were collected. Multivariable linear regression analyses were performed to determine the relationship between VCA and demographic factors. Results: The VCA ranged from 23.2° to 42.6°, with a mean of 32.2° (SD = 3.79). Mean VCA was 32.8 (SD = 4.17) in the youngest cohort (<27 years) and 30.4 (SD = 3.63) in the oldest cohort (>65 years). Mean VCA decreased with age, approximately 0.04° per year after adjusting for sex. Men had a 1.6° greater VCA than women after adjusting for age. Conclusion: Mean VCA was greater than the VCA of modern volar locking plates. The VCA decreased with age in both men and women, and men had a greater VCA than women. Such differences must be taken into account to avoid malreduction, tendon irritation, or intra-articular screw placement using current volar plate designs.

Diagnosing Infection in Patients Undergoing Conversion of Prior Internal Fixation to Total Hip Arthroplasty.

BACKGROUND: Criteria for diagnosis of infected internal fixation implants at the time of conversion to total hip arthroplasty (THA) are not clear. The purpose of this study is to identify risk factors for infection in patients undergoing conversion to THA. METHODS: We retrospectively reviewed patients at a single institution who underwent conversion to THA from 2009 to 2014. Patients were diagnosed with infection preoperatively using Musculoskeletal Infection Society criteria or postoperatively if they were found to have positive cultures intraoperatively at the time of conversion surgery. Medical comorbidities and preoperative inflammatory markers were compared between infected and noninfected groups. Univariate and multivariate logistic regression analysis were performed to identify independent risk factors for infection. Receiver operating characteristic curves were generated to determine test performance of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). A post hoc power analysis was performed. RESULTS: Thirty-three patients were included in the study. Six patients (18%) were diagnosed with infection. We found no association between comorbidities and infection in this cohort. The mean ESR and CRP were higher in infected (ESR = 41.6 mm/h, CRP = 2.0 mg/dL) vs noninfected (ESR = 19.3 mm/h, CRP = 1.3 mg/dL) groups (both P < .01). ESR >30 mm/h (odds ratio 28.8, 95% confidence interval 2.6-315.4, P = .001) and CRP >1.0 mg/dL (odds ratio 11.5, 95% confidence interval 1.6-85.2, P = .01) were strongly associated with infection. Receiver operating characteristic curves for ESR (area under the curve [AUC] = 0.89) and CRP (AUC = 0.89) demonstrated good fit. CONCLUSION: We report a high incidence of infection in patients who underwent conversion to THA. Preoperative ESR and CRP are effective screening tools though occult infections may still be missed. Patients with borderline or elevated inflammatory markers should raise strong suspicion for infection.

Combined RT-qPCR of mRNA and microRNA Targets within One Fluidigm Integrated Fluidic Circuit.

The ability to profile expression levels of a large number of mRNAs and microRNAs (miRNAs) within the same sample, using a single assay method, would facilitate investigations of miRNA effects on mRNA abundance and streamline biomarker screening across multiple RNA classes. A protocol is described for reverse transcription of long RNA and miRNA targets, followed by preassay amplification of the pooled cDNAs and quantitative PCR (qPCR) detection for a mixed panel of candidate RNA biomarkers. The method provides flexibility for designing custom target panels, is robust over a range of input RNA amounts, and demonstrated a high assay success rate.