[Preoperative management in fast-track arthroplasty]. / Prästationäres Management in der Fast-Track-Endoprothetik.

BACKGROUND: Preoperative management of patients following fast-track arthroplasty protocols includes comprehensive patient information and risk stratification. IMPLEMENTATION: Fast-track protocols have implemented interdisciplinary patient seminars to explain the disease, operation, pain management, early mobilisation and each step of the patient pathway, as well as the role of a friend or relative as a "coach" during the whole process of treatment and rehabilitation to support and encourage the patient. There is strong evidence that preoperative anxiety is reduced. Digital apps can provide further information, practical tips and instructional videos to improve functional outcomes and to reduce pain levels. RISK FACTORS: Risk factors such as malnutrition, obesity, smoking, alcohol abuse, uncontrolled diabetes, and poor dental health are associated with a higher morbidity, mortality, complication rate and a longer length of stay and have to be assessed preoperatively and optimized if possible.

[Anesthesiological concepts in fast-track arthroplasty]. / Anästhesiologische Konzepte in der Fast-Track-Endoprothetik.

Whereas only a few years ago the only expectation of skilful anesthesia was an undisturbed execution of surgical procedures, today this has changed to a perioperative responsibility in which all physicians involved in the treatment process try to optimize the existing circumstances and risks of the patient before, during and after surgery. Thus, the tasks for the anesthesiologist have been mainly extended to a rapid recovery strategy with as few side effects as possible, such as nausea and vomiting or postoperative cognitive deficits (POCD). The establishment of evident structures and the introduction of suitable perioperative procedures with the goal of maintaining homeostasis, adequate opioid-sparing pain treatment and rapid postoperative convalescence determine the anesthesiological fast-track concept.

[Challenges of fast-track arthroplasty in Germany]. / Herausforderungen der Fast-Track-Endoprothetik in Deutschland.

BACKGROUND: While fast-track arthroplasty has been already established in many European countries and the United States, Germany still struggles to introduce appropriate programs. This is due to a variety of reasons. REASONS: From an organizational and medical scope, the fear of alteration, the adherence to restrictions rooted in historical tradition, the reluctance to interdisciplinary cooperation, and the lack of a willingness to implement externally-guided process analysis tools, stand in the foreground. This is system related, and especially the DRG-system with the continuous devaluation of lump compensation rates in primary hip and knee arthroplasty, also in 2020, hinders the implementation. The resulting fears and concerns that an additional reduction of the length-of-stay by fast-track programs is leading to a consistent reduction of the DRG returns, are understandable. On the other hand, the disconnectedness of the ambulatory, inpatient and rehabilitation sector in Germany inhibits the introduction of fast-track programs. SOLUTIONS: A well-thought-out change-management is the basic requirement for the successfull establishment of a Fast-Track-Program. Perspectively, a rethinking towards sector-comprehensive care strategies for the implantation of a total hip or knee replacement, including the required rehabilitation procedures, has to be demanded.

[Preoperative management and patient education in fast-track arthroplasty]. / Präoperatives Management und Patientenschulung in der Fast-Track-Endoprothetik.

BACKGROUND: Patient management and education are essential for successful fast-track hip/knee arthroplasty. Individual risk stratification as well as educational seminars play an important role in optimizing preoperative risk factors. OBJECTIVES: Preoperative risk factors are discussed, and optimization strategies are highlighted in the context of the current literature. Further, our own results of an interdisciplinary patient seminar and a patient information app shall be discussed. MATERIALS AND METHODS: In addition to the authors' own strategy concerning preoperative patient management and the execution of the patient information seminar and app, the essential papers from the literature will be discussed. RESULTS: Preoperative risk factors (diabetes, obesity, anaemia, etc.) bear the danger of a prolonged length-of-stay with increased morbidity and mortality. Preoperative optimization can reduce the risk of complications and minimize the failure of the fast-track pathway. Educational seminars and patient information apps may reduce anxiety and postoperative analgesic consumption. CONCLUSION: A good preoperative patient management in fast-track arthroplasty can reduce the risk of complications and a prolonged length-of-stay. A comprehensive patient education with educational seminars and an app contributes to optimally preparing the patient for surgery.

[Fast track strategies in hip arthroplasty]. / Fast-Track-Strategien in der Hüftendoprothetik.

BACKGROUND: Fast track arthroplasty is becoming increasingly accepted in German-speaking countries. By optimizing treatment processes fast track programs promise faster recovery, increased patient satisfaction, quality improvement and reduction in the length of hospital stay. OBJECTIVES: The philosophy and treatment principles of fast track hip arthroplasty during the pre, intra and postoperative phase are described in the light of the current body of evidence. The challenges concerning fast track arthroplasty within the German health system are discussed. MATERIAL AND METHODS: Besides presenting our own data concerning a patient seminar and an opiate saving pain treatment, the most relevant literature related to fast track hip arthroplasty from a pubmed search is discussed. RESULTS: Fast track concepts can only be successfully implemented through close interdisciplinary team work. Preoperatively, a patient seminar can help to prepare patients better for surgery. Postoperatively, early mobilisation and pain treatment play a central role, whereat a clear reduction in opiate application can be achieved. CONCLUSION: Fast track hip arthroplasty makes rethinking with respect to traditional treatment principles necessary and demands a high degree of interdisciplinary team work. Particularly, as result of the specifics of the health system (DRG system and stationary rehabilitation), a nationwide establishment in Germany has not taken place so far.

[Cell-based and future therapeutic strategies for femoral head necrosis]. / Zellbasierte und zukünftige Therapieansätze der Femurkopfnekrose.

BACKGROUND: The application of cell- and growth factor-based techniques in conjunction with conventional surgical approaches has great therapeutic potential for the treatment of avascular necrosis of the femoral head (AVNFH). OBJECTIVES: This review provides an overview of new strategies for the treatment of AVNFH, with emphasis on cell and growth factor-based approaches. MATERIALS AND METHODS: The results of a literature search are summarised, the most relevant publications are presented and discussed by the authors. RESULTS: In the focus of new strategies for treatment of AVNFH are bone marrow-derived cell concentrates and ex vivo-expanded mesenchymal stem cells. Besides local application during core decompression, the systemic administration of cells via blood vessels supplying the femoral head is an interesting approach. The application of osteogenic and angiogenic growth factor-laden scaffold materials has also been clinically tested. Initial results of randomised clinical trials using cell- and growth factor-based approaches underline the potential of these innovative therapeutic strategies. Cell-based therapies are governed by EU law and generally require a manufacturing authorization. CONCLUSION: To date, only few randomized controlled clinical trials are available which additionally display a considerable diversity concerning cell parameters, cell processing, adjuvant surgical techniques and the quality outcome parameters. Therefore, a final statement about the effectiveness of new cell and growth factor-based strategies is currently not possible.

Extent of Microstructural Tissue Damage Correlates with Hemodynamic Failure in High-Grade Carotid Occlusive Disease: An MRI Study Using Quantitative T2 and DSC Perfusion.

BACKGROUND AND PURPOSE: Chronic hemodynamic impairment in high-grade carotid occlusive disease is thought to cause microstructural abnormalities that might be subclinical or lead to subtle symptoms including cognitive impairment. Quantitative MR imaging allows assessing pathologic structural changes beyond macroscopically visible tissue damage. In this study, high-resolution quantitative T2 mapping combined with DSC-based PWI was used to investigate quantitative T2 changes as a potential marker of microstructural damage in relation to hemodynamic impairment in patients with unilateral high-grade carotid occlusive disease. MATERIALS AND METHODS: Eighteen patients with unilateral high-grade ICA or MCA stenosis/occlusion were included in the study. T2 values and deconvolved perfusion parameters, including relative CBF, relative CBV, and the relative CBF/relative CBV ratio as a potential indicator of local cerebral perfusion pressure, were determined within areas with delayed TTP and compared with values from contralateral unaffected areas after segmentation of normal-appearing hypoperfused WM and cortical regions. Hemispheric asymmetry indices were calculated for all parameters. RESULTS: Quantitative T2 was significantly prolonged (P < .01) in hypoperfused tissue and correlated significantly (P < .01) with TTP delay and relative CBF/relative CBV reduction in WM. Significant correlations (P < .001) between TTP delay and the relative CBF/relative CBV ratio were found both in WM and in cortical areas. CONCLUSIONS: Quantitative T2 can be used as a marker of microstructural tissue damage even in normal-appearing GM and WM within a vascular territory affected by high-grade carotid occlusive disease. Furthermore, the extent of damage correlates with the degree of hemodynamic failure measured by DSC perfusion parameters.

[New experimental strategies in cartilage surgery]. / Neue experimentelle Ansätze in der Knorpelchirurgie.

BACKGROUND: Cell and growth factor based strategies bear great potential to support the healing processes in cartilage repair and the therapy of osteoarthritic joints. OBJECTIVES: The following review provides an overview of novel experimental strategies for the therapy of focal cartilage defects and osteoarthritis, with emphasis on cell and growth factor based approaches. MATERIALS AND METHODS: The authors summarize their own data regarding the intraarticular injection of stem cells to treat osteoarthritis of the knee and provide a synopsis of the available literature discussing the most significant publications. RESULTS: The development of novel strategies for the treatment of focal and arthrotic cartilage lesions focuses on the application of growth factors, platelet rich plasma (PRP), bone marrow (BMSAC) or adipose derived (stromal vascular fraction - SVF) cell concentrates, and ex vivo expanded mesenchymal stem cells (MSC). First clinical data on the use of expanded MSCs show the potential of this innovative therapeutic strategy. These approaches, however, are governed by EU law and often require approval by regulatory bodies. CONCLUSION: Currently, only a limited number of published, randomized, controlled trials available. Therefore, it is not possible to finally assess the efficacy of these strategies at this point in time.

[Extensor mechanism complications in revision total knee arthroplasty : Joint exposure and prevention of extensor mechanism complications]. / Komplikationen am Streckapparat in der Revisionsknieendoprothetik : Exposition und Vermeidung von Komplikationen am Streckapparat.

BACKGROUND: Revision total knee arthroplasty is complex surgery that has to be well planned from its indication to the actual surgical procedure. OBJECTIVES: To review surgical techniques that allow a secure exposure of the joint in revision total knee arthroplasty. MATERIALS AND METHODS: The authors summarize a review of the literature and present their own experience in knee joint exposure aiming to minimize extensor mechanism complications in revision TKA. RESULTS: The choice of adequate skin incision, detailed scar removal and a systematic soft tissue release are inevitable prerequisites for an optimal joint exposure and the minimization of extensor mechanism complications. In most patients, a medial parapatellar arthrotomy is sufficient to expose the knee joint and, if necessary, allows a proximal extension using a quadriceps snip or VY-quadricepsplasty, or a distal extension via a tibial tubercle osteotomy. Whether the quick and easy quadriceps snip or a tibial tubercle osteotomy has to be performed depends in each case on the extent of scar formation, the extensor mechanism contracture and the preoperative position of the patella. In general, a parapatellar and lateral release has to be executed; therefore, a partial lateral facetectomy ensures a secure eversion of the patella. Alternative approaches to access the joint do not reveal significant advantages and play a minor role in revision total knee arthroplasty. CONCLUSION: Revision total knee arthroplasty is a challenging surgical procedure. In addition to the regular soft tissue release techniques and joint approaches, the surgeon has to be aware of proximal and distal extension procedures to securely expose the joint and minimize the risk of extensor mechanism complications.

[Patellar tendon injuries after total knee arthroplasty : Classification and management]. / Rupturen der Patellarsehne nach Kniegelenkersatz : Klassifikation und Management.

BACKGROUND: Ruptures of the patellar tendon after total knee arthroplasty represent a rare but severe complication, which in general requires surgical therapy. OBJECTIVES: To implement a classification and correspondent therapy algorithm in consideration of the current literature for the treatment of patellar tendon ruptures after TKA. MATERIAL AND METHODS: A review of the recent literature and the author's experience are summarized in a classification and correspondent therapy algorithm for the treatment of patellar tendon ruptures after TKA. RESULTS: Ruptures of the patella tendon can be classified as avulsions (Type I), acute (Type II) and chronic ruptures (Type III). Avulsions are often of iatrogenic nature and can be sufficiently treated by transosseous refixation prior to implantation of the revision TKA. Acute ruptures of the patellar tendon can originate from trauma or intraoperative injury. The rupture can be restored by primary suture in combination with a wire cerclage in the case of good tendon quality and the absence of patient comorbidities (Type IIA). In the case of poor tendon quality or existing comorbidities (Type IIB) additional augmentation of the ruptured tendon, utilizing the autologous semitendinosus/gracilis tendon, is recommended. Chronic ruptures revealing a good patellar bone stock (Type IIIA) can be treated by a combination of a semitendinosus augmentation and a turndown quadriceps tendon flap. In the case of a poor patellar bone stock (Type IIIB) transpatellar fixation of the semitendinosus tendon is virtually impossible, so that an allograft augmentation or the use of a soft tissue muscle flap (i. e. the gastrocnemius flap) has to be considered. A failed complex reconstruction with or without infection (Type IIIC) is an invidious surgical task and needs to be addressed by the utilization of a muscle flap, an allograft or a patellectomy with or without arthrodesis.

Autologous chondrocyte implantation (ACI) for cartilage defects of the knee: A guideline by the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU).

BACKGROUND: Autologous chondrocyte implantation (ACI) is an established and well-accepted procedure for the treatment of localised full-thickness cartilage defects of the knee. METHODS: The present review of the working group "Clinical Tissue Regeneration" of the German Society of Orthopaedics and Trauma (DGOU) describes the biology and function of healthy articular cartilage, the present state of knowledge concerning therapeutic consequences of primary cartilage lesions and the suitable indication for ACI. RESULTS: Based on best available scientific evidence, an indication for ACI is given for symptomatic cartilage defects starting from defect sizes of more than three to four square centimetres; in the case of young and active sports patients at 2.5cm(2), while advanced degenerative joint disease needs to be considered as the most important contraindication. CONCLUSION: The present review gives a concise overview on important scientific background and the results of clinical studies and discusses the advantages and disadvantages of ACI. LEVEL OF EVIDENCE: Non-systematic Review.

S3-Guideline non-traumatic adult femoral head necrosis.

INTRODUCTION: The treatment of adult non-traumatic avascular necrosis of the femoral head (AVN; N-ANFH) within an estimated incidence of 5000-7000 cases per annum in Germany remains a challenge. Risk factors include steroids, alcohol abuse, chemotherapy and immunosuppressive medication, but a genetic predisposition has been suggested. Early diagnosis of this often bilateral disease process is essential for successful conservative or joint preserving surgical management. In this review, we present the update German consensus S3 guideline "diagnosis and management for N-ANFH" as a concise summary. MATERIALS AND METHODS: This systematic review is based on the published literature from January 1, 1970 to April 31, 2013 (German and English language). Inclusion criteria were systematic reviews, meta-analyses and relevant peer review publications. We identified a total of 3715 related publications, of which 422 were suitable according to the SIGN criteria, but only 159 fulfilled our inclusion criteria. RESULTS AND CONCLUSIONS: Clinical suspicion of N-ANFH mandates radiographic evaluation. If radiographs are normal MRI scans are recommended, which should be evaluated according to the ARCO-classification. Differential diagnoses include transient osteoporosis, bone bruise, insufficiency fracture and destructive arthropathy. Untreated, subchondral fractures commonly occur within 2 years, during which the risk for contralateral involvement is high-thereafter unlikely. Conservative management with Ilomedin and Alendronat can be tried, but other pharmacological or physical treatments are inappropriate. No specific joint preserving procedure can be recommended, but core decompression should be considered in early stages if necrosis is <30 %. In ARCO stages IIIc or IV total hip arthroplasty (THA) should be contemplated, which offers similar outcome compared to osteoarthritis. Young age is the main risk factor for higher revision rates after THA for N-ANFH.

[S3 Guideline. Part 1: Diagnosis and Differential Diagnosis of Non-Traumatic Adult Femoral Head Necrosis]. / S3-Leitline. Teil 1: Diagnostik und Differenzialdiagnostik der atraumatischen Femurkopfnekrose (aFKN) des Erwachsenen.

Non-traumatic femoral head necrosis (FHN) is primarily a disease of the middle-aged adult. Early diagnosis, at a time with lacking or minimal clinical symptoms, is mandatory to consider conservative therapy or joint preserving operations as a therapeutic option. The new German S3 guideline about diagnosis and therapy of FHN is a cooperative effort of five professional medical societies, overall headed by the Deutsche Gesellschaft für Orthopädie und Orthopädische Chirurgie (DGOOC). This review (part I/III) cites and explains the statements of the S3 guideline as agreed on the use of imaging methods for diagnosis of FHN. A diagnostic algorithm is presented. FHN clinically has to be considered in case of equivocal pain of a hip joint with a minimum of 6 weeks duration, when risk factors can be revealed, groin pain at clinical investigation, limping, pain or limitation of movement in case of load, and no obvious differential diagnoses. Is an FHN clinically suspected, primarily radiographs of the pelvis ap and a Lauenstein projection of the hip involved should be carried out. When the radiographs are normal, an MRI of the hips should follow routinely. MRI allows the diagnosis of FNH with high accuracy. Furthermore, MRI reveals the site and the size of the necrotic area involved and evaluates the integrity of the joint surface and subchondral fractures. When ARCO stage II (ARCO: Association Research Circulation Osseous) is diagnosed and MRI does not allow one to determine the joint surface with certainty, a CT of the hip joints should be performed. The S3 guideline explains and recommends the use of the ARCO classification. Although, this classification of 1993 is still largely based on radiographs, the pragmatic use of an "extended" version seems reasonable. Today, classical radiographic criteria like impression of the joint surface and subchondral fractures ("crescent sign") are better to be evaluated by MRI, in cases of subtle findings MRI is even surpassed by CT. The extent of the necrosis in the femoral head as well as the size of the surface area involved is best revealed with MRI. Additionally, in the era of cross sectional imaging a stage "0" seems obsolete. The guideline also addresses practically important considerations about the differential diagnosis of misleading MRI findings. This especially holds true for bone marrow oedema in the femoral head which may be misinterpreted. The differentiating features between FHN, transient bone marrow oedema and destructive arthropathy are discussed.

[S3 Guideline. Part 3: Non-Traumatic Avascular Necrosis in Adults - Surgical Treatment of Atraumatic Avascular Femoral Head Necrosis in Adults]. / S3-Leitlinie. Teil 3: Atraumatische Femurkopfnekrose des Erwachsenen - Operative Therapie der atraumatischen Femurkopfnekrose des Erwachsenen.

The present article describes the guidelines for the surgical treatment of atraumatic avascular necrosis (aFKN). These include joint preserving and joint replacement procedures. As part of the targeted literature, 43 publications were included and evaluated to assess the surgical treatment. According to the GRADE and SIGN criteria level of evidence (LoE), grade of recommendation (EC) and expert consensus (EK) were listed for each statement and question. The analysed studies have shown that up to ARCO stage III, joint-preserving surgery can be performed. A particular joint-preserving surgery currently cannot be recommended as preferred method. The selection of the method depends on the extent of necrosis. Core decompression performed in stage ARCO I (reversible early stage) or stage ARCO II (irreversible early stage) with medial or central necrosis with an area of less than 30 % of the femoral head shows better results than conservative therapy. In ARCO stage III with infraction of the femoral head, the core decompression can be used for a short-term pain relief. For ARCO stage IIIC or stage IV core decompression should not be performed. In these cases, the indication for implantation of a total hip replacement should be checked. Additional therapeutic procedures (e.g., osteotomies) and innovative treatment options (advanced core decompression, autologous bone marrow, bone grafting, etc.) can be discussed in the individual case. In elective hip replacement complications and revision rates have been clearly declining for decades. In the case of an underlying aFKN, however, previous joint-preserving surgery (osteotomies and grafts in particular) can complicate the implantation of a THA significantly. However, the implant life seems to be dependent on the aetiology. Higher revision rates for avascular necrosis are particularly expected in sickle cell disease, Gaucher disease, or kidney transplantation patients. Furthermore, the relatively young age of the patient with avascular necrosis should be seen as the main risk factor for higher revision rate. The results after resurfacing (today with known restricted indications) and cemented as well as cementless THA in aFKN are comparable for the appropriate indication to those in coxarthrosis or other diagnoses. Regardless of the underlying disease endoprosthetic treatment in aFKN leads to good results. Both cemented and cementless fixation techniques can be recommended.

[S3 guideline. Part 2: Non-Traumatic Avascular Femoral Head Necrosis in Adults - Untreated Course and Conservative Treatment]. / S3-Leitlinie. Teil 2: Atraumatische Femurkopfnekrose des Erwachsenen - unbehandelter Verlauf und konservative Behandlung.

BACKGROUND: In Germany there are 5000 to 7000 new cases of atraumatic avascular necrosis of the femoral head in adults per year. It occurs mostly in middle age. An increased frequency of idiopathic cases can be observed. Chemotherapy, corticoids and kidney transplants are frequently associated with the disease. In most cases the disease occurs on both sides. Early diagnosis is of particular importance, since in early stages it is most likely to avoid late damage with joint destruction. Whereas previously the temporary operational joint preservation and subsequent joint replacement were often the only option of treatment, conservative and joint-preserving measures today play an increasing role. MATERIAL AND METHODS: After the AWMF guidelines for S3 guideline clinical questions were formulated. Over the period from 01/01/1970 to 31/05/2013 a literature search was conducted. Systematic reviews, metaanalyses, original papers and clinical trials of all designs were evaluated. There were a total of 3715 references, of which 422 for the assessment regarding SIGN were eligible and finally 180 were in accord with the defined inclusion and exclusion criteria. For the untreated course and the assessment of conservative measures, a total of 42 references was suitable. In formulating the recommendations the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) system was used, which distinguishes A "shall", B "should" and 0 "can". RESULTS AND CONCLUSION: If left untreated, the aFKN within 2 years leads to a subchondral fracture and subsequent collapse. After the diagnosis of femoral head necrosis, the risk of a disease of the opposite side is high within the next 2 years, then unlikely. The sole conservative treatment brings no benefit for the treatment of atraumatic avascular necrosis in the adult. Although it improves function, less pain can be obtained, and surgical intervention can be delayed, the progression is not stopped. Conservative treatment must therefore always be part of the overall treatment. In ARCO stage I to II Iloprost may be considered as a pharmacological approach to reduce the pain and the bone marrow oedema. This also applies to alendronate. Since this is an off-label use, and thus a therapeutic trial, an appropriate patient education must take place. For the use of anticoagulants and statins, there is no recommendation. Also the hyperbaric oxygen therapy, shock waves and pulsating electromagnetic fields or electrical stimulation cannot be recommended.

Quantitative MR Imaging of Brain Tissue and Brain Pathologies.

Measurement of basic quantitative magnetic resonance (MR) parameters (e.g., relaxation times T1, T2*, T2 or respective rates R (1/T)) corrected for radiofrequency (RF) coil bias yields different conventional and new tissue contrasts as well as volumes for tissue segmentation. This approach also provides quantitative measures of microstructural and functional tissue changes. We herein demonstrate some prospects of quantitative MR imaging in neurological diagnostics and science.

Functional cartilage repair capacity of de-differentiated, chondrocyte- and mesenchymal stem cell-laden hydrogels in vitro.

OBJECTIVE: The long-term performance of cell-seeded matrix-based cartilage constructs depends on (1) the development of sufficient biomechanical properties, and (2) lateral integration with host tissues, both of which require cartilage-specific matrix deposition within the scaffold. In this study, we have examined the potential of tissue-engineered cartilage analogs developed using different cell types, i.e., mesenchymal stem cells (MSCs) vs chondrocytes and de-differentiated chondrocytes, in an established "construct in cartilage ring" model. DESIGN: Cell-laden constructs of differentiated chondrocytes, de-differentiated chondrocytes after two, five or eight population doublings, and MSCs were either implanted into a native cartilage ring immediately after fabrication (immature group) or pre-treated for 21 days in a transforming growth factor-ß3 (TGF-ß3) containing medium prior to implantation. After additional culture for 28 days in a serum-free, chemically defined medium, the extent of lateral integration, and biochemical and biomechanical characteristics of the implants as hybrid constructs were assessed. RESULTS: The quality of integration, the amount of accumulated cartilage-specific matrix components and associated biomechanical properties were found to be highest when using differentiated chondrocytes. De-differentiation of chondrocytes negatively impacted the properties of the implants, as even two population doublings of the chondrocytes in culture significantly lowered cartilage repair capacity. In contrast, MSCs showed chondrogenic differentiation with TGF-ß3 pre-treatment and superior integrational behavior. CONCLUSIONS: Chondrocyte expansion and de-differentiation impaired the cell response, resulting in inferior cartilage repair in vitro. With TGF-ß3 pre-treatment, MSCs were able to undergo sustained chondrogenic differentiation and exhibited superior matrix deposition and integration compared to de-differentiated chondrocytes.

[Post-treatment rehabilitation after autologous chondrocyte implantation: State of the art and recommendations of the Clinical Tissue Regeneration Study Group of the German Society for Accident Surgery and the German Society for Orthopedics and Orthopedic Surgery]. / Nachbehandlung bei der autologen Chondrozytentransplantation: Eine Bestandsaufnahme und Empfehlung der AG Klinische Geweberegeneration der DGU/DGOOC.

BACKGROUND: Over the course of the past two decades autologous chondrocyte implantation (ACI) has become an important surgical technique for treating large cartilage defects. The original method using a periostal flap has been improved by using cell-seeded scaffolds for implantation, the matrix-based autologous chondrocyte implantation (mb-ACI) procedure. MATERIAL AND METHODS: Uniform nationwide guidelines for post-ACI rehabilitation do not exist. A survey was conducted among the members of the clinical tissue regeneration study group concerning the current rehabilitation protocols and the members of the study group published recommendations for postoperative rehabilitation and treatment after ACI based on the results of this survey. RESULTS: There was agreement on fundamentals concerning a location-specific rehabilitation protocol (femoral condyle vs. patellofemoral joint). With regard to weight bearing and range of motion a variety of different protocols exist. Similar to this total agreement on the role of magnetic resonance imaging (MRI) for postsurgical care was found but again a great variety of different protocols exist. CONCLUSIONS: This manuscript summarizes the recommendations of the members of the German clinical tissue regeneration study group on postsurgical rehabilitation and MRI assessment after ACI (level IVb/EBM).