Similar-sized patellar tendon autografts and fresh-frozen allografts were used to reconstruct the anterior cruciate ligament of one knee in 40 female goats. Evaluations of the reconstructions and contralateral controls at the 6-week and 6-month postoperative periods included anterior-posterior translation, mechanical properties determined during tensile failure tests, measurement of cross-sectional area, histology, collagen fibril size and area distribution, and associated articular cartilage degenerative changes. Six months after anterior cruciate ligament reconstruction, the autografts demonstrated a smaller increase in anterior-posterior displacement, values of maximum force to failure two times greater, a significant increase in cross-sectional area, a more rapid loss of large-diameter collagen fibrils, and an increased density and number of small-diameter collagen fibrils compared to the allografts. Clinical significance. More surgeons are allowing their patients to return to running and sports 6 months after anterior cruciate ligament reconstruction. While the structural and material properties of autografts and allografts at time zero are similar, in the goat model during the first 6 months they differ. The allografts demonstrate a greater decrease in their implantation structural properties, a slower rate of biologic incorporation, and the prolonged presence of an inflammatory response. At 6 months the autograft demonstrates a more robust biologic response, improved stability, and increased strength to failure values.
Ultrasonography (US) is usually the initial imaging modality for evaluation of pathologic conditions of the scrotum. However, magnetic resonance (MR) imaging can be useful as a problem-solving tool when sonographic findings are equivocal. MR imaging allows characterization of scrotal masses as intratesticular or extratesticular and can demonstrate various types of lesions and tissue, including cysts or fluid, solid masses, fat, and fibrosis. MR imaging may be of value when the location of a scrotal mass is uncertain or when US does not allow differentiation between a solid mass and an inflammatory or vascular abnormality. Gadolinium-enhanced MR imaging can help differentiate between a benign cystic lesion and a cystic neoplasm. Gadolinium-enhanced imaging can also be used to demonstrate areas of absent or reduced testicular perfusion, such as in segmental testicular infarct. Finally, MR imaging can demonstrate an intraabdominal undescended testis, which can be difficult to detect with US, and is superior to US in differentiation between an undescended testis and testicular agenesis.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.