[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.

[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.

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.

[Reconstruction of osteochondral defects with a collagen I hydrogel. Results of a prospective multicenter study]. / Rekonstruktion von Gelenkknorpeldefekten mit einem Kollagen-I-Hydrogel. Ergebnisse einer prospektiven Multicenterstudie.

STUDY GOALS: The aim of the study was to evaluate the therapeutic benefit of CaReS®, a type I collagen hydrogel-based autologous chondrocyte implantation technique, for the treatment of osteochondral defects of the knee (Outerbridge grades III and IV) within a prospective multicenter study. MATERIAL AND METHODS: A total of 116 patients in 9 clinical centers were treated with CaReS between 2003 and 2008. The Cartilage Injury Evaluation Package 2000 of the International Cartilage Repair Society (ICRS) was employed for data acquisition and included the subjective International Knee Documentation Committee score (IKDC score), the pain level (visual analog scale, VAS), the physical and mental SF-36 score, the overall treatment satisfaction and the functional IKDC status of the indexed knee. Follow-up evaluation was performed 3, 6 and 12 months after surgery and annually thereafter. RESULTS: The mean defect size treated was 5.4 ± 2.7 cm(2) with 30% of the cartilage defects being ≤4 cm(2) and 70% ≥4 cm(2). The mean follow-up period was 30.2 ± 17.4 months (minimum 12 months and maximum 60 months). The mean IKDC score significantly improved from 42.4 ± 13.8 preoperatively to 70.5 ± 18.7 (p < 0.01) in the mean follow-up period. Global pain level significantly decreased (p < 0.001) from 6.7 ± 2.2 preoperatively to 3.2 ± 3.1 at the latest follow-up. Both the physical and mental components of the SF-36 score significantly increased. At the latest follow-up 80% of the patients rated the overall treatment satisfaction as either good or very good. The functional IKDC knee status clearly improved from preoperative to the latest follow-up when 23.4% of the patients reported having no restriction of knee function (I), 56.3% had mild restriction (II), 17,2% had moderate restriction (III) and 3.1% revealed severe restriction (IV). CONCLUSIONS: The CaReS technique is a clinically effective and safe method for the reconstruction of isolated osteochondral defects of the knee joint and reveals promising clinical outcome up to 5 years after surgery. A longer follow-up period and larger patient cohorts are needed to evaluate the sustainability of CaReS treatment.

A nanofibrous cell-seeded hydrogel promotes integration in a cartilage gap model.

The presence of a defect in mature articular cartilage can lead to degenerative changes of the joint. This is in part caused by the inability of cartilage to regenerate tissue that is capable of spanning a fissure or crack. In this study, we hypothesized that introduction of a biodegradable cell-seeded nanofibrous hydrogel, Puramatrix(), into a cartilage gap would facilitate the generation of a mechanically stable interface. The effects of chondrocyte incorporation within the hydrogel and supplementation with transforming growth factor-beta3 (TGFbeta3), a known regulator of cell growth and differentiation, on cartilage integration were examined mechanically and histologically as a function of cell density and incubation time. When supplemented with TGFbeta3, the cell-seeded hydrogel exhibited abundant matrix generation within the hydrogel and a corresponding increase in maximum push-out stress as compared to all other groups. Furthermore, initial cell seeding density affected interfacial strength in a time-dependent manner. This study suggests that a cell-seeded TGFbeta3-supplemented hydrogel can encourage integration between two opposing pieces of articular cartilage.

[Cell based therapy for the treatment of femoral head necrosis]. / Zellbasierte Therapie der Femurkopfnekrose.

The goal of the therapy for necrosis of the femoral head in adults is the preservation of the femoral head and, therefore, avoidance of total joint replacement. Core decompression is known to reduce the intraosseous pressure and additionally provides the opportunity to introduce bioactive materials, substances and cells into the core tract. These include vascularized and non-vascularized bone grafts, allogenic and synthetic bone substitutes, osteogenic and angiogenic growth factors, as well as different progenitor cells. In particular, the use of cell-based strategies has great therapeutic potential and could play an important role in the treatment of femoral head necrosis in adults in the future. In this article, we summarize the existing clinical experience of current cell-based strategies for the treatment of femoral head necrosis in adults, and present a therapeutic approach using bone marrow stem cells (TRCs: tissue repair cells). in combination with a beta-TCP matrix.