Mini-midvastus total knee arthroplasty does not result in superior gait pattern.

PURPOSE: Previous studies dealing with gait after minimally invasive surgery (MIS) total knee arthroplasty (TKA) are rare and insufficient. It was the purpose of the study to determine in a prospective, comparative setting whether MIS influences the outcome of TKA in terms of typical 3D gait parameters. METHODS: Patients scheduled for TKA or MIS TKA were invited to participate. MIS TKA was defined as TKA with shorter skin incision, mini-midvastus arthrotomy, special instruments, and avoidance of tibiofemoral dislocation and patella eversion. All other intra- and perioperative aspects were identical for both groups. A 3D gait analysis was performed with a VICON system 1 month preoperative and 8 weeks post-operative. A multivariate analysis of variance was conducted including the main effects time (pre- and post-surgery) and surgical group and the group-by-time interaction effect. RESULTS: Seventeen MIS TKA patients and 20 TKA patients were eligible for the final analysis. We determined neither inter-group differences nor time × group interactions for any gait variables (temporospatial, ground reaction forces, joint angles and joint moments)­except for the varus-valgus knee kinematics. In pre- to post-operative comparison, the maximum valgus sway increased in the MIS group, whereas it decreased in the conventional group (p = 0.001). CONCLUSION: From our findings, it was concluded that MIS TKA does not result in a superior walking pattern 8 weeks post-operative. Because we previously also observed mini-midvastus MIS TKA to have equal or slightly inferior results with regard to knee scores, knee torque, radiographic outcome and tourniquet/operating time, we discontinued the procedure. LEVEL OF EVIDENCE: Prospective comparative study, Therapy, Level II.

Mechanism of fatal air embolism after gastrointestinal endoscopy.

Although venous air embolism is a known complication in medical practice in general, only a single case of upper gastrointestinal endoscopy complicated by venous air embolism with consecutive acute cardiovascular failure has so far been described in literature. Here we show that gastroscopy may be accompanied by massive, i.e. fatal venous air embolism. If a vessel in the gastrointestinal tract is exposed but does not collapse (in the case of a gastric ulcer, for example) air insufflated under pressure by the gastroscope may lead to a fatal air embolism. Our tests using a commercial gastroscope revealed that an overpressure of up to 43 kPa (kiloPascals) is reached without the rinsing function while an overpressure of up to 45 kPa is measured if the rinsing function is operated simultaneously. The maximum flow rates without resistance were 100 ml/min for rinsing liquid (purified water) and 2000 ml/min for air. Our results suggest that air insufflation by the gastroscope may result in a critical air embolism within very few seconds on condition that a connection with the vascular system exists. However, this complication is extremely rarely encountered. We propose that CO2 should be administered in place of air or alternatively the maximum pressure should be considerably reduced to avoid a fatal outcome in routinely performed gastroscopical examinations.

[Determination of back shape in median sagittal plane using an inclination sensory]. / Feststellung der Rückenform in der Mediansagittalebene mittels Neigungssensoren.

The measurement and assessment of the shape of the human back is in the process of becoming an important area of research. Various measuring techniques have already been developed, including moiré topography, stereoscopic photography and raster stereography. These have been employed in the evaluation of scoliosis, kyphosis, funnel chest and other pathological conditions of the spine. These systems are very complicated (and expensive) since they involve a three-dimensional analysis of the shape of the back. For preventive medical purposes, however, evaluation of the spine in the median sagittal plane alone often suffices. In this study, the inclinations of the back along the spine were measured, and it has been shown that these measurements can be used to reconstruct the shape of the back.