In total knee arthroplasty (TKA), intramedullary and extramedullary tibial alignment guides are not proven to be highly accurate in obtaining alignment perpendicular to the mechanical axis in the coronal plane. The objective of this study was to determine the accuracy of an accelerometer-based, handheld surgical navigation system in obtaining a postoperative tibial component alignment within 2°...

A new flip-chip solder technology has been developed for the precision self-alignment of an optoelectronic module without using mechanical stops. A main feature of the technology is the controlled self-alignment sequence: laser is aligned to a polymer waveguide in the lateral and vertical directions, then it slowly makes a contact with the waveguide in the axial direction. The elimination of th...

We present a general mathematical theory for the mechanical interplay in tissue-equivalents (cell-populated collagen gels): Cell traction leads to compaction of the fibrillar collagen network, which for certain conditions such as a mechanical constraint or inhomogeneous cell distribution, can result in inhomogeneous compaction and consequently fibril alignment, leading to cell contact guidance,...

BACKGROUND Restoration of a neutral mechanical axis is a primary goal of total knee replacement (TKR). A mechanical axis within 3° of neutral has been correlated with improved implant longevity, function, and patient satisfaction. We hypothesize that the immediate post-operative radiograph is an unreliable method of measuring alignment following TKR surgery. METHODS Seventy-five consecutive p...

BACKGROUND Despite good results of primary total knee arthroplasty (TKA), the number of revision total knee arthroplasties (rTKAs) is rising. Proper implant position is essential, since malposition leads to worse clinical outcome. In rTKA most anatomical landmarks have disappeared because of extensive bone loss, making it more difficult to adequately implant the knee prosthesis. In primary TKA,...

IF A prosthetic device is to give optimum service to the amputee, it must always be properly fitted, regardless of its mechanical excellence. This is especially true in the case of the lower extremity, where the prosthesis must function continually and where poor fit or alignment will lead quickly to rejection of the device by the wearer. Among prosthetists there seems to be general agreement t...

Collagen fiber re-alignment and uncrimping are postulated mechanisms of structural response to load. It has been suggested that fibers re-orient in the direction of load and then "uncrimp" before collagen is tensioned and that in general, the structure is a result of the function tendons perform. However, little is known about how fiber re-alignment and uncrimping change in response to load, ho...

Mechanical forces play an important role in shaping the organization of the extracellular matrix (ECM) in developing and mature tissues. The resulting organization gives the tissue its unique functional properties. Understanding how mechanical forces influence the alignment of the ECM is important in tissue engineering, where recapitulating the alignment of the native tissue is essential for ap...