Der Unfallchirurg
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The aim of this study was to document the changes in retropatellar pressure, contact area and forces due to different sizes and placement of the patella resurfacing in knee arthroplasty. Six cadaver specimens (after Thiel fixation) were examined after the implantation of the total knee arthroplasty Genesis I. The patella sizes "small" and "medium" were placed as the "onlay" version, centered as well as off-centered by 0.4 cm in all four directions. ⋯ For the medium size, maximum pressure (P = 0.03) increased significantly and force decreased significantly (P = 0.0277) whereas contact area and average pressure increased slightly. The results of the different placements of the patella implant do not support the recommendation for a medial shift. However, at least the lateralized implantation led to a reduction of contact area and force as well as to a slight increase of pressure which is considered as unfavorable.
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We performed a clinical and radiological analysis to evaluate the significance of the stem position of cementless CLS components with respect to function and survival. We used patient material from a multi-center study of 3,732 CLS stems with a mean follow-up of 43 months (range: 12-142 months). ⋯ In patients with rheumatoid arthritis and hip ankylosis the neutral stem position was less often achieved than in patients with other diagnoses. The results of our study cast doubt on whether the varus position of the femoral component of cementless tapered CLS-type stem designs is as critical as in cemented total hip arthroplasty.
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Case Reports
[Intramedullary nail placement with percutaneous Kirschner wires. Illustration of method and clinical examples].
Unreamed nailing is an established method for internal fixation of femoral und tibial shaft fractures. The interlocking technique allows the stabilization of metaphyseal fractures, too, but the risk of malalignment increases. ⋯ The method is easy to use and suited particularly in combination with the UFN and UTN, but is in principal applicable to other nails, too. In contrast to the "Poller Screw" method developed by Krettek et al., no biomechanical augmentation of the osteosynthesis remains.
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Comparative Study
[Proximal interlocking of humeral intramedullary nails and risk of axillary nerve injury].
Possible injuries to the axillary nerve are criticised in antegrade and retrograde endomedullary nailing of the humeral shaft during proximal interlocking. Clinical experience seems not to support the theory of a high risk of nerve injury. The real risk although remains unknown under anatomical-morphological aspects. ⋯ We suggest to perform only a sharp cutaneous incision and then to prepare the muscle only by careful spreading until touching bone, with tissue retraction during drilling. In retrograde nailing the dorso-ventral bolt should only be used in extreme proximal fractures.
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A 21-year-old man experienced an open knee injury with a subtotal loss of the medial part of the distal femur. After an initial debridement of the wound we performed 48 hours post injury an allogeneic transplantation of the condyle of the femur. ⋯ The bone transplant hadn't been treated specifically prior to the transplantation and the patient didn't receive any immunodepressive drugs. 18 months later, the patient is able to flex the knee joint up to 120 degrees and to extend it completely. The overall result is excellent.