Biomechanische Aspekte der präoperativen Planung: Was ist wirklich wichtig?

BackgroundSagittal balance is dependent on acomplex interplay of the spinal curves, shape and setting of the pelvis, but also the position of the joints of the lower limb. Degenerative processes such as stiffening of the spine, aging of musculature, or reduction of the range of motion of the joints lead to imbalance of the spine after all compensatory mechanisms have been exhausted.ObjectivesBased on standardized imaging, compensation mechanisms must be identified within abiomechanical analysis of the spine, the original sagittal spine profile anticipated and included in the planning of the corrective intervention.ResultsThis review presents the most important global and spinopelvic parameters for the biomechanical analysis of the spine. In addition, normal variations of the sagittal alignment are discussed, compensation mechanisms are shown, and the planning of the rebalancing of the sagittal alignment is shown according to the full balance integrated model

Schmerzverlauf nach operativer orthopädischer Intervention

The number of cases of orthopedic surgery is still increasing and postoperative pain management is of great importance for the patients. Therefore, in this study factors influencing the pain and the developement of pain in general in the first 7 days after total knee arthroplasty were examined. A total of 28 patients were included in this prospectively designed trial and underwent total knee arthroplasty with psoas compartment and sciatic nerve regional anesthesia and additionally propofol sedation. Postoperative pain scores were documented using a numerical rating scale (NRS) and anthropometric data and perioperative parameters were correlated with the postoperative pain score. Evaluation of the pain values per interval showed that the maximum and the mean postoperative pain levels decreased up to day 4 after surgery and then increased. No significant effects of the analyzed parameters age, body mass index (BMI), duration of surgery and catheter indwelling time could be found. Female patients had significantly more pain than males in this collective. The results show that there were no factors which have a significant influence on the degree of postoperative pain. Female patients suffered from more pain than males. There was an increase in pain after postoperative day 4 which might be the effect of more extensive mobilization and reduced effects of regional anesthesia. It is important that pain is treated in the early postoperative period

Even the Intraoperative Knowledge of Femoral Stem Anteversion Cannot Prevent Impingement in Total Hip Arthroplasty

Background: In this prospective study of 66 patients undergoing cementless total hip arthroplasty through a minimally invasive anterolateral approach, we evaluated the impact of an intraoperative hybrid combined anteversion technique on postoperative range of motion (ROM). Methods: After navigation of femoral stem anteversion, trial acetabular components were positioned manually, and their position recorded with navigation. Then, final components were implanted with navigation at the goals prescribed by the femur-first impingement detection algorithm. Postoperatively, three-dimensional computed tomographies were performed to determine achieved component position and model impingement-free ROM by virtual hip movement, which was compared with published values necessary for activities of daily living. This model was run a second time with the implants in the position selected by the surgeon rather than the navigation program. In addition, we researched into risk factors for ROM differences between the freehand and navigated cup position. Results: We found a lower flexion of 8.3 degrees (8.8 degrees, P < .001) and lower internal rotation of 9.2 degrees (9.5 degrees, P < .001) for the freehand implanted cups in contrast to a higher extension of 9.8 degrees (11.8 degrees, P < .001) compared with the navigation-guided technique. For activities of daily living, 58.9% (33/56) in the freehand group compared with 85.7% (48/56) in the navigation group showed free flexion (P < .001) and similarly 50.0% (28/56) compared with 76.8% (43/56) free internal rotation (P < .001). Body mass index, incision length, and cup size were identified as independent risk factors for reduced flexion and internal rotation in the freehand group. Conclusion: For implementation of a combined anteversion algorithm, intraoperative alignment guides for accurate cup positioning are required using a minimally invasive anterolateral approach. Obese patients are especially at risk of cup malpositioning. (C) 2016 Elsevier Inc. All rights reserved