Introduction: The osteochondral transplantation (OCT) is a well accepted treatment option for focal cartilage lesions in the knee joint, whereas the fate of the transplanted cartilage is still unclear and the clinical outcome is variable. The purpose of this study was to evaluate the histological character of autologous transplanted cartilage and to correlate technical aspects and the patients’ history with the clinical outcome. Material and Methods: The OCT was performed in 27 patients (median age of 32 (22–43) years) with a focal chondral lesion at the medial femoral condyle. We investigated the clinical outcome after a median follow-up of 13.5 (5–28) months using the Lysholm-score and the integration of the transplanted plugs using an MRI-scoring system. Biopsy specimens from representative patients (n=8) were evaluated with histological staining and immunohistochemistry. Results: The median Lysholm-score was 80 (range 45–98). The wide range of the Lysholm-score in clinical outcome did not show significant differences in: follow-up, concomitant injuries, defect size or genesis. The MRI analysis revealed in all cases a regular osseous integration of the subchondral bone, but a failed chondral integration. The congruency of the plugs to the joint surface was often incorrect, however a correlation between the MRI-score and the clinical outcome could not be shown. Histology of the transplanted cartilage revealed small changes in immunohistochemistry after a relatively short-term follow-up, whereas the cartilage has still the typical hyaline character. Often, the surrounding cartilage consists of fibrous and granulation tissue. Conclusion: The congruency of the joint surface can not be restored to the original status, particularly in larger defects with irregular shapes. However, we did not find any aspects which affected the function of the knee joint following OCT. It can be assumed that remaining lesions at the surrounding cartilage could maintain the inflammatory process and therefore maintain the pain and a low knee function. Further investigations are needed to specify the effects of the OCT on the transplanted cartilage and its influence on the later clinical outcome.

Laser surgery of the larynx is characterized by a very small working space. The laryngoscope develops a high pressure on maxilla and tongue. During the procedure repeated changes of the position are necessary to provide sufficient view. The mechatronic assistance system should achieve a lower complication rate, a shorter duration of the surgical procedure and an improved ergonomy. We investigated first the power and torque on 15 microlaryngoscopy (mls) procedures. Additionally the evaluation of 21 surgical workflows of mls and assistance profile are described. We defined the surgical efficiency criteria for the desired product. Further we analysed the surgeon-machine interaction on 2 models. In a prototypical study we determined on realistic model the valuable mode of action. The measurements of power and torque resulted in an average maximum level of continuous stress of 20 N for 90 s during the positioning of the larynx. The passive leading through the working space by predefined memory positions turned out as a valuable interaction between surgeon and assistance system. The new developed concept fulfills the principal demands on an efficient mechatronic leading system for laser surgery of the larynx and hypopharynx. Further steps should work on modification of instruments and technical synchronisation of microscopic and laryngoscope movements. (c) 2005 Published by Elsevier B.V.