Radiographic Anatomy of the Native Anterior Cruciate Ligament: a Systematic Review

BackgroundIn an attempt to improve the accuracy and reproducibility of tunnel positioning, radiographs are being analyzed in an attempt to recreate the native anatomy of the ACL. Understanding the native ACL radiographic anatomy is an essential prerequisite to understand the relevance of postoperative tunnel position.Questions/PurposesWe performed a systematic review of the literature to delineate the radiographic location of the native ACL femoral and tibial footprints.MethodsA search was performed in March 2014 in PubMed, the Cochrane Collaboration Library, and EMBASE to identify all studies that evaluated the native anterior cruciate ligament (ACL) anatomy on radiographs. Various measurement methods were used in each study, and averages were obtained of the data from studies with the same measurement methods.ResultsFifteen papers were identified (which included data on 177 femora and 207 tibiae in total). Evaluation of the femoral footprint using the quadrant method on lateral knee radiographs showed that the average percent distance location of the anteromedial (AM) bundle and posterolateral (PL) bundle was 22.8% (95% confidence interval (CI) 16.59–28.90) and 32.5% (95% CI 27.71–37.26) from the posterior condyle, respectively, and 23.2% (95% CI 19.52–26.94) and 50.0% (95% CI 46.16–53.76) from Blumensaat’s line, respectively. Using the Amis and Jacob method, the tibial footprint on the lateral knee radiograph average percent distances was 35.1% (95% CI 34.46–35.72) for the center of the AM bundle and 47.3% (95% CI 41.69–52.95) for the center of the PL bundle of the ACL. The femoral and tibial ACL footprints on the anteroposterior (AP) views of the knee were not well delineated by these studies.ConclusionThe information presented in this systematic review offers surgeons another important tool for accurate ACL footprint identification.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-014-9417-5) contains supplementary material, which is available to authorized users.     

Benznidazole-resistance in Trypanosoma cruzi is a readily acquired trait that can arise independently in a single population

Benznidazole is the frontline drug used against Trypanosoma cruzi, the causative agent of Chagas disease. However, treatment failures are often reported. Here, we demonstrate that independently acquired mutations in the gene encoding a mitochondrial nitroreductase (TcNTR) can give rise to distinct drug-resistant clones within a single population. Following selection of benznidazole-resistant parasites, all clones examined had lost one of the chromosomes containing the TcNTR gene. Sequence analysis of the remaining TcNTR allele revealed 3 distinct mutant genes in different resistant clones. Expression studies showed that these mutant proteins were unable to activate benznidazole. This correlated with loss of flavin mononucleotide binding. The drug-resistant phenotype could be reversed by transfection with wild-type TcNTR. These results identify TcNTR as a central player in acquired resistance to benznidazole. They also demonstrate that T. cruzi has a propensity to undergo genetic changes that can lead to drug resistance, a finding that has implications for future therapeutic strategies.     

Practice Effects and Longitudinal Cognitive Change in Normal Aging vs. Incident Mild Cognitive Impairment and Dementia in The Mayo Clinic Study of Aging

The objective of this study was to examine practice effects and longitudinal cognitive change in a population-based cohort classified as clinically normal at their initial evaluation. We examined 1390 individuals with a median age of 78.1 years and re-evaluated them up to four times at approximate 15-month intervals, with an average follow-up time of 5 years. Of the 1390 participants, 947 (69%) individuals remained cognitively normal, 397 (29%) progressed to mild cognitive impairment (MCI), and 46 (3%) to dementia. The stable normal group showed an initial practice effect in all domains which was sustained in memory and visuospatial reasoning. There was only a slight decline in attention and language after visit 3. We combined individuals with incident MCI and dementia to form one group representing those who declined. The incident MCI/dementia group showed an unexpected practice effect in memory from baseline to visit 2, with a significant decline thereafter. This group did not demonstrate practice effects in any other domain and showed a downward trajectory in all domains at each evaluation. Modeling cognitive change in an epidemiologic sample may serve as a useful benchmark for evaluating cognitive change in future intervention studies.     

A Panel Interview on the Ethical Practice of Neuropsychology

Neuropsychologists who have considerable experience reflecting, presenting, publishing, and advising on ethical matters are a rich resource for clinicians who have ethics questions. Consultation with such colleagues can be an important part of the ethical decision-making process. The purpose of the present article is to provide the opinions and perspectives of three neuropsychologists who, based on their experience and scholarly activities, served as panelists regarding ethical matters. Although the advice and opinions of colleagues are not a substitute for familiarity with relevant ethical requirements, guidelines, and professional literature, they offer valuable information that enhances the ethical decision-making process.     

A Model to Approaching and Providing Feedback to Patients Regarding Invalid Test Performance in Clinical Neuropsychological Evaluations

The use of symptom validity assessment has become commonplace in clinical neuropsychological evaluations. However, clinicians often struggle with how to provide patients with feedback regarding invalid responding or effort, because of the sensitive nature of the information that must be conveyed. A conceptual framework for providing such feedback is outlined in clinical neuropsychological evaluations, and recommendations for how to handle complaints are offered. Our feedback model is not meant to apply to individuals referred by attorneys or other non-clinical third parties (e.g., independent medical examination companies).     

HIV risk among men who have sex with men who have experienced childhood sexual abuse: systematic review and meta-analysis

Previous research has indicated a high prevalence of childhood sexual abuse (CSA) among men who have sex with men (MSM) in the United States, and has suggested that CSA history is a risk factor for HIV infection in MSM. We conducted a systematic review to identify, synthesize, meta-analyze, and critique the current state of relevant literature. Systematic review methodology was utilized to identify 12 studies that compared MSM with a history of CSA to MSM without a history of CSA on HIV risk indicators including HIV serostatus, sexually transmitted infections (STIs), sexual behaviors, and illicit drug use. Overall, 27.3% (n = 4,263) of the MSM in all included studies (n = 15,622) reported a CSA history. Across the studies that used probabilistic sampling (n = 8,240), the estimated prevalence of CSA was 21.8% (n = 1,800). Meta-analysis indicated that MSM with CSA history were more likely to be HIV positive [odds ratio (OR) = 1.54; 95% confidence interval (CI) = 1.22-1.95)] and to engage in recent unprotected anal intercourse (OR = 1.85, 95% CI = 1.36-2.51). Studies also indicated that MSM with a history of CSA were more likely to report frequent casual male partners, substance use, and sex while under the influence of alcohol or other drugs. Trends across studies indicated a need for interventions to assess CSA history and address effects of CSA on sexual risk behavior of MSM. Inconsistencies across studies indicated a need to reach consensus among researchers and providers in defining CSA.