Recommendations for return to sports after total hip arthroplasty are becoming less restrictive as implants improve.

INTRODUCTION: Total hip arthroplasty (THA) surgeries are expected to exponentially increase in the upcoming years, likely because of the overall broader indication of THAs. With these developments, an increasing number of younger (< 50 years) and active patients will receive surgical interventions, and expectations for an active lifestyle will accordingly increase. In addition, surgeons now have a growing array of techniques and implant materials to choose from. Despite these developments, evidence to provide the best standard-of-care to patients with high expectations for return to sports (RTS) is scarce and urgently needed. What recommendations do arthroplasty surgeons currently make to patients with high return to sports expectations, what factors may influence their recommendations and what surgical techniques and implant specifications are considered favorable in the treatment of patients with a more active lifestyle? This study was conducted to analyze the current recommendations, patient assessment, and patient counseling after THA to identify trends and relevant factors for surgical decision-making in patients with high-RTS expectations. MATERIAL AND METHODS: We designed a questionnaire comprising five general items and 19 specific items that included 46 sub-items for hip arthroplasty and conducted a survey among 300 German surgeons specialized in arthroplasty at the German Arthroplasty Society (AE) to assess expert opinions, recommendations, surgical decision-making, and patient counseling for patients with high expectations for RTS after THA. RESULTS: The majority of surgeons (81.9%) were in favor of RTS after THA. Risks associated with sports after THA were considered minimal (1%), with periprosthetic fractures ranking highest, followed by hip dislocation and polyethylene wear. Some surgical decision-making was influenced by high-RTS expectations in regard to implant fixation, stem type, femoral head diameter, and bearing-surface tribology. We observed an increasingly liberal counseling of patients for high-impact sports. CONCLUSION: With the improvement of implants and surgical techniques, surgeons are more willing to encourage patients to adopt a more active lifestyle. However, the true long-term limitations need further investigation in future studies. LEVEL OF EVIDENCE: 5 Expert opinions.

[Diagnosis of periprosthetic joint infection : Development of an evidence-based algorithm by the work group of implant-associated infection of the AE-(German Society for Arthroplasty)]. / Diagnostik der periprothetischen Infektion : Entwicklung eines evidenzbasierten Algorithmus der Arbeitsgruppe implantatassoziierte Infektion der Arbeitsgemeinschaft Endoprothetik.

BACKGROUND: Prosthetic joint infections (PPI) will challenge orthopaedic surgeons and the health care system in the coming years. Evidence-based and reliable preoperative diagnostics are necessary for success in the field of revision arthroplasty. Especially the preoperative detection of PPI is important with respect to the treatment strategy. AIM: The aim of this study was to develop a detailed and structured standard operating procedure (SOP) to detect PPI preoperatively. METHODS: A systematic literature research was performed and relevant articles identified. After extracting the data, statistical calculations of sensitivity, specificity, positive/negative predictive value and positive/negative likelihood ratio were performed. The results were discussed and evaluated in four meetings analogously to standard Delphi rounds by the workgroup of implant-associated infections of the German AE (Arbeitsgemeinschaft Endoprothetik). An algorithm for the diagnostic approach according to ISO 5807 was made. RESULTS: The standardized algorithm combines a sequence of evidence-based procedures with detailed and structured main and additional criteria to every critical step in the diagnostic approach. CONCLUSION: The detection of PPI is of tremendous importance prior to revision arthroplasty and determines its success or failure. The diagnosis "prosthetic joint infection" requires a substantial change with respect to treatment concepts. The algorithm summarizes current literature and specialized expert opinions in a modern standardized format for a transparent diagnostic approach.

[Surgery of sepsis in orthopedics and trauma - A highlight : Current survey by the section for bone and soft tissue infections of the German Society for Orthopedics and Trauma]. / Septische Chirurgie in OuU ­ ein Schlaglicht : Aktuelle Umfrage der DGOU-Sektion Knochen- und Weichteilinfektionen.

Surgery of sepsis in trauma surgery and orthopedics is attracting increasingly more attention due to the rising presence of multidrug-resistant pathogens and the increasing number of operative interventions. Despite extensive experience over decades neither the symptoms nor the treatment strategies have been evaluated and it has become obvious that a scientific investigation of this complex topic is necessary for optimization of patient care under economically sound conditions. The aim of this article is to give a snapshot from German healthcare institutions for trauma surgery and orthopedics to answer some questions on this topic from the section for bone and soft tissue infections (SeKuWi) of the German Society for Orthopedics and Trauma (DGOU) in cooperation with the German Society for Hospital Hygiene (DGKH).

Pulmonary metastasectomy for metastasized hepatocellular carcinoma after liver resection and liver transplantation: a single center experience.

BACKGROUND: The role of surgery in the treatment of metastasized hepatocellular carcinoma (HCC) remains uncertain. We here report our single centre experience with pulmonary metastasectomy (PM) for metachronous HCC metastases to the lung following curative liver resection (LR) and liver transplantation (LT), respectively. METHODS: Of 270 patients with HCC being treated by LR or LT at the University Hospital of Leipzig between January 1996 and July 2014, PM was performed in the follow up of 10 patients because of metachronous pulmonary HCC metastases. We retrospectively analyzed demographic and clinicopathological factors as well as the outcome after primary and secondary tumor treatment in these patients. RESULTS: Following LR/LT and metastasectomy, respectively, mean overall survival was 4.58 ± 0.84 years and 2.4 ±â€Š0.69 years. Postoperative morbidity after primary and secondary tumor treatment was 30 % and 20 %, respectively. Perioperative 30-day mortality was 0 %. Univariate analysis suggest tumor grading (p < 0.05), and a disease free-intervall > 1 year (p = 0.02) as significant prognostic parameters for survival in our collective. CONCLUSION: PM can be performed safely with a reasonable morbidity even in immunosuppressed patients after LT. Further studies are needed to evaluate whether PM can increase long-term survival in selected patients with resectable metastases and represents an alternative or additive treatment modality to the protein kinase inhibitor sorafenib.

[Synovialitis of the arthrofibrotic type: criteria of a new synovialitis type for the diagnosis of arthrofibrosis]. / Synovialitis vom arthrofibrotischen Typ: Kriterien eines neuen Synovialitis-Typus für die Diagnose der Arthrofibrose.

After rheumatologic conservative medical therapy has been exhausted in degenerative and inflammatory joint diseases, arthroplastic operations are an important option to restore quality of life. Endoprosthesis-associated arthrofibrosis is a severe fibrosing disease of the synovial membrane after endoprosthetic operations. Neither the morphological substrate nor histopathological criteria have been described. The aim was to describe the histopathological substrate of arthrofibrosis and to define histological and immunohistochemical criteria of arthrofibrosis on the basis of tissue samples derived from revision. In histopathological analyses arthrofibrosis revealed a synovialitis with varying fibrosis, without detectable ossification and without minimal wear particle reaction (so-called synovialitis of arthrofibrotic type, SAT). A 3-stage grading was determined based on the cellular density of the fibrous tissue (fibroblast cellularity). In 191 cases with SAT, grade 1 was found in 24.1 % (n = 46), grade 2 was found in 51.8 % (n = 99) and grade 3 was found in 24.1 % (n = 46). The control group consisted of 29 cases with synovialitis of indifferent type (type IV membrane). If SAT grades 2 and 3 are summed together, i.e. the distance between the fibroblasts was less than two cell lengths, the difference of the fibroblast cellularity compared with the type IV membrane was significant (p < 0.001). Above SAT grade 2 the diagnosis of arthrofibrosis could be made with a sensitivity 0.7592 and specificity 0.8276. The SM-alpha-actin cytoplasmic positivity of fibroblasts indicates a myofibroblast phenotype and the ß-catenin positivity suggests a resemblance to fibromatosis or a keloid-like process. In the quantitative evaluation of the ß-catenin positive fibroblasts, there was a significant difference (p < 0.001) between type IV membrane and SAT. A threshold value of 20 beta-catenin positive cells per microscopic high power field (HPF) was determined, which represents in conjunction with the clinical information a new histopathological diagnosis component (sensitivity 0.720, specificity 0.867).

[Revised consensus classification. Histopathological classification of diseases associated with joint endoprostheses]. / Erweiterte Konsensusklassifikation. Histopathologische Klassifikation von Gelenkendoprothesen-assoziierten Erkrankungen.

The revised classification of the periprosthetic membrane (synovial-like interface membrane SLIM) encompasses all pathological alterations which can occur as a result of endoprosthetic replacement of major joints and lead to a reduction in durability of prostheses. This also includes the established consensus classification of SLIM by which aseptic and septic prosthetic loosening can be subdivided into four histological types and histopathological criteria for additional pathologies: endoprosthesis-associated arthrofibrosis, immunological/allergic alterations and osseous pathologies. This revision represents the foundation for the histopathological diagnostics of the total spectrum of diseases associated with joint prostheses, is a suitable basis for a standardized diagnostic procedure and etiological clarification of endoprosthesis failure and also as a data standard for endprosthesis registers, in particular for registers based on routine data (e.g. German endoprosthesis register).

[Joint endoprosthesis pathology. Histopathological diagnostics and classification]. / Gelenkendoprothesenpathologie. Histopathologische Diagnostik und Klassifikation.

Prosthesis durability has steadily increased with high 10-year rates of 88-95%. However, four pathogenetic groups of diseases can decrease prosthesis durability: (1) periprosthetic wear particle disease (aseptic loosening) (2) bacterial infection (septic loosening) (3) periprosthetic ossification, and (4) arthrofibrosis. The histopathological "extended consensus classification of periprosthetic membranes" includes four types of membranes, arthrofibrosis, and osseous diseases of endoprosthetics: The four types of neosynovia are: wear particle-induced type (type I), mean prosthesis durability (MPD) in years 12.0; infectious type (type II), MPD 2.5; combined type (type III) MPD 4.2; and indeterminate type (type IV), MPD 5.5. Arthrofibrosis can be determined in three grades: grade 1 needs clinical information to be differentiated from a type IV membrane, and grades 2 & 3 can be diagnosed histopathologically. Periprosthetic ossification, osteopenia-induced fractures, and aseptic osteonecrosis can be histopathologically diagnosed safely with clinical information. The extended consensus classification of periprosthetic membranes may be a diagnostic groundwork for a future national endoprosthesis register.

[Infection management of megaimplants]. / Infektionsmanagement bei Megaimplantaten.

More and more megaprostheses are being implanted - not just injuries or primary and secondary bone tumors, but also the increase in extended bone defects in revision arthroplasty call for the more frequent use of megaimplants. Underlying disease, medication, age, and frequency of surgical procedures give rise to infections which occur in more than 10% of the patients receiving megaprostheses. Size, surface, and design of the implants themselves increase the infection rate.Every year we treat more than 45 patients with periprosthetic infections of megaimplants and large revision prostheses, many of them infected with multi-resistant germs. MRSE and MRSA have been shown to increase the rate of relapses (19%). The treatment strategy continues to consist of multiple steps, and temporary stabilization is achieved either externally with external fixation devices or orthoses or internally with spacers (PMMA, interim implants). To avoid relapsing infections surgeons must rely on anti-infective surface coatings (silver), local drug carriers (collagen, PMMA), and especially soft tissue coverage with local muscle flaps and radical treatment of the bone infection. Amputations, however, cannot be avoided completely; 5% of our patients had to undergo amputations above the knee after infections of megaimplants.Surgery will be required more frequently to treat infections of megaprostheses and increase the medical, nursing, logistic, technological, and financial burden on the patients, surgeons, clinics, and insurance companies.

An evaluation of retrieved UHMWPE hip joint cups.

In this study it is demonstrated that the combined chemical and mechanical influences of the implant situation cause property changes of ultra-high-molecular-weight polyethylene (UHMWPE) hip joint cups. Nearly 250 loosened hip cups, retrieved 3 weeks to 14 years after implantation, were investigated. The clinical long-term behavior of various shaped polyethylene hip sockets are statistically analyzed. The main damage features were defined and described. Density measurements show a density increase with implantation time and a dependence of these changes from implant position and loading conditions. The rate of extractable constituents also increases with course of time. An increased in vivo conditioned oxidation of the UHMWPE can be demonstrated by infrared (IR) spectrometry. The density increase can be explained by post-crystallization, which is the result of oxidative chain scission. This leads to a reduction of the average molecular weight of the PE and to an increased extractability of constituents. Since these changes have been recognized as the reasons for aging and failing of UHMWPE, the methods of material characterization used in this study for retrieved implants will help to develop suitable in vitro testing and simulating methods. Characteristic damage features of hip cups allow direct relationships with construction characteristics and their improvement.

Non-linear three-dimensional finite element analysis of a cementless hip endoprosthesis.

In this finite element study the stresses between a stem component of a cementless hip endoprosthesis (Young modulus of Co-Cr-Mo) and the human femur were calculated for two different loading types. Linear and non-linear models were used to simulate the interface implant bone. Two models, a stem with a porous coated surface over the entire length and a stem with a porous coated surface in the proximal region were compared regarding the load transmission to the femur. An additional calculation of an 'isoelastic' stem (Young modulus of cortical bone) was done to show the influence of the stem stiffness. A porous coated surface over the entire length causes principal shear stresses up to 2.75 MPa in the distal-medial region during level walking. The highest compressive stresses were calculated in the proximal-lateral region as 1.5 MPa in cancellous bone. A more physiological load transmission is obtained by limiting the coated area to the proximal region. All stresses in the two models are lower than experimentally evaluated strengths in the interface between implant and bone. A strong influence of the Young modulus of the stem material on the interface stresses was found. An 'isoelastic' stem causes compressive stresses in the proximal-lateral region whose values exceed the experimental strength of cancellous bone.

[Immunization against blood group antigens by allogeneic bone transplantation]. / Immunisierung gegen Blutgruppenantigene durch allogene Knochentransplantation.

33 bone allotransplants (cryopreserved) of AB0- and Rh-incompatible (donor-recipient) patients were performed to evaluate the question which AB0 Rh-incompatibility leads to immunization of the bone transplant recipient. Several different antibodies were tested pre- and postoperatively in the recipient. Regarding the Rh-system no immunization was demonstrable; however, a significant increase of antibody leads was found regarding the AB0-system. Thus, in bone bank techniques AB0 compatibility is important for allogeneic bone transplantation in young women. Otherwise, there is a risk for the development of MHN in case of pregnancy. Blood group-typing is not necessary in other patient groups. Although no Rh-antibodies were demonstrable, a similar mechanism can be postulated for the Rh-system. We, thus, conclude that in allogeneic bone tx in young women the Rh-system has to be taken into consideration.

[A method for determining the biomechanical properties of trabecular and spongiosa bone tissue]. / Eine Methode zur Bestimmung biomechanischer Eigenschaften von Trabekeln und Knochengewebe der Spongiosa.

With the aim of determining the biomechanical properties of cancellous bone, a method was developed that permits the investigation of the effects of tensile and compressive forces on cancellous bone trabeculae while eliminating the problem of porosity. Individual, rod-like trabeculae were removed from cancellous bone with the aid of special instruments. Each end of a trabeculae was embedded in a cylinder of polymethylmethacrylate. To keep bending moments to a minimum while testing, the trabeculae was aligned along the longitudinal axis of the cylinders with the aid of positioning instruments. With a test apparatus, the deformation behaviour and maximum strength of the trabeculae under tension and compression can be determined under both dry and moist conditions. With account being taken of shape and dimensions of the trabeculae, the material properties of the cancellous bone tissue can be computed. In comparison with the small number of methods so far used for investigating trabeculae, a number of advantages were found: 1. Tensile and compression testing in a single specimen, 2. testing under reliably moist conditions, 3. non-destructive testing enabling further investigations on the specimen.

[Material related aspects of surface structured endoprostheses]. / Werkstoffkundliche Aspekte oberflächenstrukturierter Endoprothesen.

In this article technical problems of surface-structured endoprostheses for cementless implantation are discussed. On the basis of four prostheses (two hip and two knee endoprostheses) various different porous coating technologies are compared. One sintered sphere layer, a cast sphere layer, a cast layer with "spongy-bone" structure and a plasma sprayed coating were compared. The quality of the bonding between the prosthesis and the porous surface layer was examined metallographically using polished specimens, with additional investigation of fraction surfaces of special tension test specimens. Additional information is given on the notch effect of the different coatings, in terms of a reduction in fatigue strength. The notch sensitivity differs for each material, and the reduction in fatigue strength is discussed for different implant alloys and different technologies for surface structuring. The investigation shows that the present quality of surface-structured endoprostheses is not satisfactory. We would like to thank the Dr. Johannes Heidenhain Foundation for financial support of this research.

[Biomechanics of healing of cortical autotransplants after intramedullary nailing and device removal]. / Biomechanik der Heilung kortikaler Autotransplantate nach Marknagelung und Materialentfernung.

The aim of the study was to investigate the biomechanical properties of segmental cortical autografts subjected to extracorporeal treatment. For this purpose, 12 beagle dogs were submitted to tibial osteotomy, when 25 mm-long diaphyseal segments of bone were removed and treated outside the body by autoclaving or gamma radiation (Co, 5 kGy). Subsequently, osteosynthesis involving the use of medullary nailing was performed. After 36 weeks, the dogs were killed painlessly and, after removing the nails, the tibias were tested for the biomechanical properties. In comparison with the contralateral tibia, a mean stiffness of 47% and 32% was measured for tibia treated by irradiation and autoclaving, respectively, while bending showed an increase of up to 590%. These results show the need to allow plenty of time for healing in the case of weightbearing transplants. When bealing is undisturbed, no biomechanical differences are found between proximal and distal osteotomies, although in the X-ray image the osteotomy gap (fracture line) remains visible, and scintigraphic activity persists for a longer period. This means that the radiological aspect of the former does not necessarily reflect actual biomechanical strength.

[Experimental studies of the biomechanical properties of hollow nails and solid nails for interlocking intramedullary nailing in the dog]. / Experimentelle Untersuchungen über die biomechanischen Eigenschaften von Hohlnägeln und Vollnägeln zur verriegelbaren Marknagelung am Hund.

Since locked intramedullary nailing of the tibia in dogs was followed by material failure of the conventional slotted hollow nails within days, special solid nails were developed and tested with respect to their mechanical properties. There was a clear advantage of the solid nails over the hollow nails in terms of bending resistance and yield force. In animal experiments--even in long-term experiments over nine months--no case of material failure occurred with the solid nails. The high torsional and bending resistance of the solid nails suggests the use of a mechanical device which, as our experience shows, permits reliable interlocking without the need for an image intensifier, that is to say, without radiation exposure.

[The value of epidemiologic studies of ski injuries]. / Zur Aussagekraft epidemiologischer Studien über Verletzungen beim Skisport.

The Garmisch-Partenkirchen experience--15,513 skiing injuries between 1972 and 1990--was compared to the results of an inquiry into the skiing injuries among 565 persons of the medical profession, that were active skiers over an average of 18 years. The parameter injuries per 1000 skiing days was calculated from the outpatient clinic data as well as from all skiing injuries that had happened in the interview group and those that required surgical treatment. The mean value of 2.7 injuries/1000 skiing days--corrected for the number of patients--from the literature and the clinical data with 2.1 is comparable to the 1.8 injuries/1000 skiing days (injuries that required surgical treatment) but stands sharply against the 4.2 arising from the total number of injuries in the inquiry group.--Thus, every epidemiological study clearly underestimates the actual rate of skiing injuries. This fact may be defined as the "bypass-effect". The comparison between clinical setting and inquiry allowed for a quantification: Depending on the type of injury and the study design, a true prevalence of skiing injuries that is between 10% and 200% higher than the published data has to be expected.--Descriptive, not controlled epidemiologic studies on skiing injuries are justified and give valid trends on which therapeutic and prophylactic measures can be based--but exclusively under the following prerequisite conditions: 1. a standardized study protocol; 2. an observation.

[Biomechanical studies of change in the patellar tendon after transplant removal]. / Biomechanische Untersuchungen zur Veränderung der Patellarsehne nach Transplantatentnahme.

The reconstruction of the anterior cruciate ligament deficient knee with the patellar tendon is the "gold standard". Dislocation of the patella, rupture of the patellar tendon and fracture of the patella were reported to occur. In this biomechanical investigation on the changes of the patellar tendon following harvesting of a graft, 51 sheep knee underwent destructive testing at t0 (n = 11), 4 weeks p.op. (n = 5), 3 months p.op. (n = 14), 6 months p.op. (n = 15), and 12 months p.op. (n = 6). Harvesting of a graft produces a stiffness and strength of the patellar tendon of 50-70% of normal. There was no significant change of free patellar tendon length up to 12 months p.op. The cross-sectional area is definitely increased (p < 0.05). The tensile stress is always above normal, nevertheless the strength shows a massive decline until 6 months p.op. and does not regain normal strength by one year p.op. Stiffness shows comparable biomechanical pattern like tensile stress. There are time-dependent changes, the structural weakness is compensated by an increase of cross-sectional area. There is no restitution of the patellar tendon ad integrum, the remainder is a defect with scar tissue and alterated biomechanical properties. Revision surgery using the same host patellar tendon cannot be recommended.

Revised histopathological consensus classification of joint implant related pathology.

This extended classification of joint implant related pathology is a practical histopathologic classification based on defined morphological criteria covering the complete spectrum of pathohistologic changes in periprosthetic tissues. These changes may occur as a consequence of endoprosthetic replacement of large joints and may lead to a reduction in the prosthesis survival rate. We describe the established consensus classification of the periprosthetic membrane, in which aseptic and septic prosthetic loosening can be subdivided into four histological types, as well as histopathological criteria for additional significant pathologies including endoprosthetic-associated arthrofibrosis, particle-induced immunological, inflammatory and toxic mechanisms (adverse reactions), and bone tissue pathologies. These characteristic tissue alterations and their relationships are summarized in the extended classification. Since particle heterogeneity in periprosthetic tissue is high and particle identification is a necessary part of diagnosis, the identification of different types of particles is described in the histopathological particle algorithm. The morphological qualities of prosthetic material particles and the demarcation between abrasion and non-abrasion endogenous particles are also summarized. This feasible classification which is based on low cost standard tissue processing and examination and on well-defined diagnostic criteria is a solid platform for the histological diagnosis of implant associated pathologies providing a stable and reproducible tool for the surgical pathologist. Since this classification is suitable for standardized histopathological diagnostics, it might also provide a useful data set for joint arthroplasty registers, particularly for registers based on so-called routine data.