Patellotibial contusions in anterior cruciate ligament tears.

Bone contusions are an important ancillary finding of many knee injuries. Not only are they a source of pain, they may suggest a mechanism of injury or a specific derangement of the knee joint. We have encountered a small number of patients being evaluated for anterior cruciate ligament (ACL) tears with unexplained patellar and tibial edema at magnetic resonance (MR) imaging. We present three individuals with contusions of the inferior patella with a corresponding contusion of the anteromedial tibial plateau. Internal derangements in these patients were similar to other individuals with acute ACL tears, however osseous contusions were more widespread. In conclusion, patellotibial contusions are rare and may indicate an injury with forces greater than usually encountered in most ACL tears. A careful search for uncommon associated injuries is prudent in these high-energy knee injuries.

Post-traumatic pseudoaneurysm of the thyrocervical trunk.

Pseudoaneurysms of the thyrocervical trunk or its branches are extremely rare. They are often the result of a penetrating injury and commonly iatrogenic in origin. Pseudoaneurysm formation following blunt trauma has twice been reported in the English-language literature. We report a case of a 56-year-old man involved in a motor vehicle collision who presented with a slowly growing mass over the course of 4 months. A magnetic resonance (MR) examination was requested to evaluate the cause of this slowly growing mass. Our case is unique in that MR imaging correctly diagnosed the lesion, which was subsequently treated with ultrasound-guided percutaneous thrombin injection. Our case is the only published instance of treatment of a thyrocervical trunk pseudoaneurysm by direct ultrasound-guided percutaneous thrombin injection.

Single-molecule dilution and multiple displacement amplification for molecular haplotyping.

Separate haploid analysis is frequently required for heterozygous genotyping to resolve phase ambiguity or confirm allelic sequence. We demonstrate a technique of single-molecule dilution followed by multiple strand displacement amplification to haplotype polymorphic alleles. Dilution of DNA to haploid equivalency, or a single molecule, is a simple method for separating di-allelic DNA. Strand displacement amplification is a robust method for non-specific DNA expansion that employs random hexamers and phage polymerase Phi29 for double-stranded DNA displacement and primer extension, resulting in high processivity and exceptional product length. Single-molecule dilution was followed by strand displacement amplification to expand separated alleles to microgram quantities of DNA for more efficient haplotype analysis of heterozygous genes.