The Association of Cavovarus Foot Deformity With an Os Peroneum.

OBJECTIVE: We sought to assess whether the presence of an os peroneum is correlated with cavovarus foot alignment in patients without a neurologic explanation for their foot shape. We hypothesized that a large os peroneum would increase the power of the peroneus longus and lead to a forefoot-driven, hindfoot varus deformity. MATERIALS AND METHODS: This was a retrospective cohort study conducted at a single institution and reviewed patients with 3 weightbearing views of the foot on plain radiography. Patients were characterized into having either no os peroneum (235), a small os peroneum (18), or a large os peroneum (23). The control group included the first 101 of the 235 patients without an os peroneum based on a power analysis of the primary outcome, which was the difference in the mean Meary's angle (lateral talo-first metatarsal angle) between groups. The kite angle (anterior-posterior [AP] talocalcaneal angle), as well as 4 other angles were measured as secondary outcomes. RESULTS: Those with a large os peroneum had on a mean 7.7° (P < .01) more apex dorsal angulation of Meary's angle than controls, and a kite angle 4.2° varus to that of the control group. There were no differences between the small os peroneum and control groups. CONCLUSION: These findings add to the existing literature surrounding the etiology of cavovarus foot shape and link the presence of an ossified os peroneum, an oftentimes incidental radiographic finding, to cavovarus foot deformity in those without an underlying neurologic diagnosis. LEVELS OF EVIDENCE: Therapeutic, Level III: Retrospective Case-Control.

Evaluating Internal Fixation Skills Using Surgical Simulation.

BACKGROUND: Open reduction and internal fixation (ORIF) is an essential skill for an orthopaedic surgeon, yet teaching its components to surgical residents poses challenges in both complexity and cost. Surgical simulation has demonstrated efficacy and is now a mandated component of residency programs, but the techniques and resources required for effective simulation vary greatly. We hypothesized that simulation of ORIF skills could be accomplished in a cost-effective, quantifiable, and reproducible manner and that this experience coupled with didactic learning would increase skill proficiency and enhance ORIF performance. METHODS: Sixteen postgraduate-year-1 orthopaedic surgery interns were assessed on performance of ORIF simulation tasks before and after attending a module designed to introduce and practice internal fixation techniques. Simulation tasks addressed drilling accuracy via oblique drilling through polyvinyl chloride (PVC) cylinders and bisecting wooden dowels and plunge control via drilling through layered boards of varying densities. Fracture fixation simulation involved fixing oblique fractures on synthetic ulnae. Task performance was assessed at 3 time points: immediately before the module, 1 week after the module, and 3 months after the module. Fracture fixation was assessed before and after the module via load-to-failure testing. Success rates for the tasks were analyzed using a repeated-measures analysis of variance, and mechanical properties of the fixed ulnar constructs were compared using paired t tests. RESULTS: In all ORIF simulation tasks, pre-module to post-module improvement in success rates was significant (p < 0.001) and improvements were maintained between the post-module assessment and the 3-month follow-up. The interns also achieved significantly greater strengths in their ulnar fixation constructs, with a mean improvement of 256 N (p = 0.01) after the module. CONCLUSIONS: These results indicate that the technical and sensorimotor skills relevant to internal fixation (with emphasis on the specific skill of using a drill) can be significantly augmented and retained in the short term in surgical residents after exposure to faculty-led lecture and hands-on skills practice using low-cost materials. CLINICAL RELEVANCE: This study provides evidence for an effective, accessible method of enhancing and assessing surgical skills in training.

Mining gene expression data by interpreting principal components.

BACKGROUND: There are many methods for analyzing microarray data that group together genes having similar patterns of expression over all conditions tested. However, in many instances the biologically important goal is to identify relatively small sets of genes that share coherent expression across only some conditions, rather than all or most conditions as required in traditional clustering; e.g. genes that are highly up-regulated and/or down-regulated similarly across only a subset of conditions. Equally important is the need to learn which conditions are the decisive ones in forming such gene sets of interest, and how they relate to diverse conditional covariates, such as disease diagnosis or prognosis. RESULTS: We present a method for automatically identifying such candidate sets of biologically relevant genes using a combination of principal components analysis and information theoretic metrics. To enable easy use of our methods, we have developed a data analysis package that facilitates visualization and subsequent data mining of the independent sources of significant variation present in gene microarray expression datasets (or in any other similarly structured high-dimensional dataset). We applied these tools to two public datasets, and highlight sets of genes most affected by specific subsets of conditions (e.g. tissues, treatments, samples, etc.). Statistically significant associations for highlighted gene sets were shown via global analysis for Gene Ontology term enrichment. Together with covariate associations, the tool provides a basis for building testable hypotheses about the biological or experimental causes of observed variation. CONCLUSION: We provide an unsupervised data mining technique for diverse microarray expression datasets that is distinct from major methods now in routine use. In test uses, this method, based on publicly available gene annotations, appears to identify numerous sets of biologically relevant genes. It has proven especially valuable in instances where there are many diverse conditions (10's to hundreds of different tissues or cell types), a situation in which many clustering and ordering algorithms become problematic. This approach also shows promise in other topic domains such as multi-spectral imaging datasets.

Spastic foot and ankle deformities: evaluation and treatment.

Spastic foot and ankle deformities can occur from various causes and have profound effects on individuals and society. Presentations can vary clinically and a thorough clinical evaluation, potentially with a dynamic electromyogram, is essential to selecting the most appropriate treatment. Nonoperative treatments, such as orthotics, casting, oral medications, and nerve blocks, can be effective but surgery is indicated if they are no longer effective. Of the various operative procedures to treat this condition, split anterior tibialis tendon transfer and tendo Achilles lengthening are the most commonly performed. Multiple surgical options have been shown to be effective.

Flexible cavovarus foot in children and adolescents.

Flexible cavovarus feet in children and adolescents can be challenging. A careful history and physical examination are paramount for determining the best treatment strategy and a multitude of options are available. Specific treatment strategies should be individualized and any bony correction must be in conjunction with a muscle balancing procedure. Well-timed soft tissue and occasionally bony procedures can delay the progression of deformity. These patients are monitored long term because further treatment may be required.