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The Working Group of the German Orthopedic and Trauma Society (DGOU) on Tissue Regeneration has published recommendations on the indication of different surgical approaches for treatment of full-thickness cartilage defects in the knee joint in 2004, 2013 and 2016. Based upon new scientific knowledge and new developments, this recommendation is an update based upon the best clinical evidence available. In addition to prospective randomised controlled clinical trials, this also includes studies with a lower level of evidence. In the absence of evidence, the decision is based on a consensus process within the members of the working group.The principle of making decision dependent on defect size has not been changed in the new recommendation either. The indication for arthroscopic microfracturing has been reduced up to a defect size of 2 cm 2 maximum, while autologous chondrocyte implantation is the method of choice for larger cartilage defects. Additionally, matrix-augmented bone marrow stimulation (mBMS) has been included in the recommendation for defects ranging from 1 to 4.5 cm 2 . For the treatment of smaller osteochondral defects, in addition to osteochondral transplantation (OCT), mBMS is also recommended. For larger defects, matrix-augmented autologous chondrocyte implantation (mACI/mACT) in combination with augmentation of the subchondral bone is recommended., Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Competing Interests: Die Autorinnen/Autoren geben an, dass kein Interessenkonflikt besteht.

Autologous chondrocyte transplantation/implantation (ACT/ACI) is an established and recognised procedure for the treatment of localised full-thickness cartilage defects of the knee. The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Traumatology (DGOU) describes the biology and function of healthy articular cartilage, the present state of knowledge concerning potential consequences of primary cartilage lesions and the suitable indication for ACI. Based on current evidence, an indication for ACI is given for symptomatic cartilage defects starting from defect sizes of more than 3-4 cm2; in the case of young and active sports patients at 2.5 cm2. Advanced degenerative joint disease is the single most important contraindication. The review gives a concise overview on important scientific background, the results of clinical studies and discusses advantages and disadvantages of ACI., (Georg Thieme Verlag KG Stuttgart · New York.)

Articular cartilage defects have virtually no self-healing capacity. As a consequence, a surgical approach for symptomatic grade III/IV defects is required. The application of bone marrow-stimulating techniques (Pridie drilling, microfracture) is only able to reproduce mechanically inferior fibrous cartilage tissue. The minimally invasive surgical technique and low cost with acceptable results in the medium term are the main reasons for the application of these techniques. The combination of microfracture and biomaterials, i.e., the AMIC technique, has not yet proved that the disadvantages of the marrow stimulation techniques can be overcome. At present, only laboratory cultivated autologous chondrocytes are able to restore a biomechanically superior cartilage layer. By selecting the appropriate cell fraction in conjunction with the controlled release of differentiating growth factors, sufficient cartilage regeneration also appears to be achievable on the basis of bone marrow aspirate. This is the subject of experimental studies of bone marrow aspirates and autologous growth factors with encouraging initial results.

Joint cartilage damage in adults has practically no tendency to self healing. Symptomatic grade III/IV damage requires surgical treatment. There are special challenges involved in cartilage damage in the patellofemoral joint as the complicated biomechanics of the joint is often combined with dysplasia. All tissue regeneration measures are based on the recruitment of cells. The synovial cells available in the joint can be differentiated to fibrous cartilage under certain mechanical conditions; however, they cannot sufficiently fill in defects. Also the use of bone marrow cells for cartilage reconstruction only creates mechanically inferior fibrous cartilage (Pridie drillings, microfracture, AMIC). Presently only cultivated, autologous chondrocytes from the lab are available for a biomechanically high-quality reconstruction of the cartilage layer.The application of mesenchymal stem cells is a subject of extensive international research. However, the first experimental studies, after initial formation of cartilage, disappointingly show significant ossification. Essential conditions for a successful treatment of patellofemoral cartilage damage are the diagnosis of accompanying pathological conditions, selection of the right cartilage-regenerating procedure, sufficient removal of the basic pathological defect, and implementation of standardized rehabilitation.

With regard to the current demographic changes in today's population and the increasing demands of the patients i. e. in sports activity, the operative treatment of chondral lesions gained of importance in recent years. The treatment of cartilage injuries is not only of great importance in order to reduce the patients' symptoms, but also intends to avoid the appearance of secondary arthrosis. There are several different techniques available for the treatment of full-thickness defects (such as microfracture and autologous chondrocyte implantation), some of them following related principles. The choice of the optimal treatment technique remains of great importance and represents one of the major responsibilities of the surgeon in order to achieve optimal results. The current article represents a review of current techniques and developments in operative cartilage repair of the knee joint and gives help in the decision-making process, since the use of the appropriate technique becomes more and more important in order to achieve optimal clinical results.

For the treatment of full-thickness articular cartilage lesions of the knee joint, as a result of trauma or osteochondritis dissecans, a variety of biological reconstruction techniques have been developed. Different studies, some of which were performed as randomised, prospective clinical studies, showed that the autologous chondrocyte transplantation (ACT) provides the most satisfying and reliable method of cartilage reconstruction in the adult when applied to defects exceeding 4 cm (2). Based on these results, ACT seems to be of economic benefit, as the risk of developing osteoarthritis correlates significantly with the size of the cartilage defect, when not treated properly and in time. Surveying the studies on basic scientific aspects of ACT, cartilage defect animal models and clinical studies, it can be concluded that clinical results of ACT depend on a variety of factors. In this review, published by the joined advisory board of the German Societies of Traumatology (DGU) and Orthopaedic Surgery (DGOOC), we summarize the current knowledge available and the state of the art concerning ACT. Especially we discuss the advantages of different procedures, methods for treating knee cartilage defects and factors that influence the outcome of the different treatment regimens, with the aim to develop guidelines for the correct indication and application of the ACT.

Aim: The aim of this work was to control the results after simultaneous use of different modern resurfacing techniques., Methods: We examined the patients who were subjected to different cartilage repair methods using the ICRS score (anterograde drilling, autologous chondrocytes transplantation, OATS, refixation with resorbable pins, spongious bone grafting, HTO)., Results: In two cases the combination of different cartilage regenerative methods in a one-step technique produced a good reconstruction of the joint surface with good clinical outcome. With the implantation of carbon plaques, osteolysis of the spongious bone in combination with an incomplete defect filling can be observed. The therapy must be individual and take the clinical, radiological and intraoperative findings into consideration., Conclusion: The combination of different resurfacing techniques may have success only if the biomechanical properties of the joint with axial malpositioning and ligament instabilities are considered and treated as well. New prospects are offered particularly for young patients with extensive cartilage damage and without other therapeutic options.

The treatment of deep cartilage defects is a challenge for every orthopaedic surgeon. The potential for regeneration of cartilage tissue is minimal and leads to mechanically inferior fibrous tissue. The established techniques induce the growth of fibrous tissue but fail to prevent arthrosis. Autologous chondrocyte transplantation seems to be the most promising therapy concept with clinical relevance to reserves a full thickness cartilage defect with hyaline-like cartilage. Outcome studies with a follow up from 2-10 years show in up to 90 % good and excellent results for defects on the femoral condyle and 70 % for the patella. Mechanical testing of the regenerated cartilage showed almost similar stiffness as nearly normal hyaline cartilage. The available data justify the acceptance of autologous chondrocyte transplantation as a standard procedure for limited indications and well-trained surgeons. Result of already inaugurated studies will show the potential of chondrocyte transplantation to prevent osteoarthritis.

Introduction: Since the advent of operative ankle arthroscopy specific treatment of osteochondritis dissecans of the talus underwent rapid progress. Besides optimizing well-known methods as drilling, spongeous plastic, curettage or refixation of dissecates new trends go to transplantation of cultivated cartilage and osteochondral allografts. Previous follow-up examinations suffer on the one hand from partially small numbers of cases, on the other hand comparisons are difficult because so far no rating system of the function of the upper ankle does exist., Material and Methods: Within three years 34 patients underwent arthroscopic treatment of osteochondritis dissecans of the talus, 16 with percutaneous drilling, 12 spongeous plastics, three refixations and three curettages. The average age of the 22 men and 12 women was 25 years (11-48 years). A newly developed score system and a follow up MRI was used in a follow-up of 29 of the patients. Up to 100 points are given in the categories pain, stability/insecurity, efficiency/painfree walking distance, gait, differences in circumference, motility and power., Results: 27 of the 34 patients had a trauma history. 20 lesions were localized at the lateral talus, they all had a trauma history. In 7 of the 14 lesions at the medial part of the talus there was no evidence of trauma. The 29 patients in the follow-up achieved an average of 87 points, the 16 patients after K-wire drilling 85 points and the 12 patients after spongeous plastic 90 points. Deductions were noted likewise in the subjective and objective parameters. 100 points were reached by 4 patients., Discussion: Cultured chondrozytes and osteochondral grafts are new trends in treatment of osteochondritis dissecans while arthroscopically controlled spongeous plastic after curettage and K-wire drilling represent the main component of early stages with intact or partially fractured cartilage surface. Results of K-wire drilling are negligible worse than those of spongeous plastic, which is attributed to a generous perforation of the sclerosis. This is contributed to an improved preoperative diagnosis with MRI.

A 77-year-old woman who had undergone surgery of a non-malignant extracerebral retro-orbital tumor suffered postoperatively from respiratory failure due to impaired respiratory drive and unconsciousness of unknown origin and required artificial ventilation for 14 days. After cerebral and endocrinological causes had been excluded, the residual effects of diazepam were taken into consideration, since the patient had received this substance for premedication and during 3 days postoperatively (total 165 mg). After the application of flumazenil (Anexate), a specific benzodiazepine receptor antagonist, she awoke immediately and was extubated with sufficient spontaneous breathing. The hypothesis that diazepam was the causative agent for the respiratory failure and impaired consciousness was supported by the detection of high serum concentrations of diazepam and its active metabolite desmethyldiazepam. During the following 3 days repetitive injections of flumazenil were necessary to counteract recurring depression of respiration and vigilance. Thereafter further application of flumazenil was not necessary.