X List of Authors and Participants of the Expert Panel Workshop for the White Paper on Joint Replacements Prof. Dr. med. Karl-Dieter Heller Univ.-Prof. Dr. med. Rüdiger Krauspe Secretary General of the German arthroplasty President of the German Society of Orthopedics association »Deutsche Gesellschaft für Endo- and Orthopedic Surgery (Deutsche Gesellschaft prothetik (AE)« für Orthopädie und Orthopädische Chirurgie First Chairman of the German association of (DGOOC)) in 2015 senior orthopedists and trauma surgeons Director of the Department of Orthopaedics »Verband leitender Orthopäden und Unfall- Düsseldorf University Hospital chirurgen (VLOU)« Moorenstraße 5 Vice-President of the Professional Association of 40225 Düsseldorf Orthopaedic Surgeons (Berufsverband für Orthopädie und Unfallchirurgie e. V. (BVOU)) Univ.-Prof. Dr. med. Georg Matziolis Board member of the German Society of Professor of Orthopedics at the Jena University Orthopedics and Orthopedic Surgery Hospital, Campus Eisenberg (Deutsche Gesellschaft für Orthopädie und Medical Director of the Clinic for Orthopaedics Orthopädische Chirurgie (DGOOC)) and Accident Surgery at the Waldkrankenhaus Vice President of the German hip society Eisenberg (Waldkrankenhaus »Rudolf Elle« GmbH) »Deutsche Hüftgesellschaft (DHG)« Klosterlausnitzer Straße 81 Head of the Orthopedic Department 07607 Eisenberg Herzogin Elisabeth Hospital Leipziger Straße 24 Univ.-Prof. Dr. med. Henning Windhagen 38124 Braunschweig Medical Director of the Orthopaedic Clinic of the Hannover Medical School in the Dr. med. Andreas Hey DIAKOVERE Annastift Hospital Managing Director of the German arthroplasty Anna-von-Borries-Straße 1–7 registry 30625 Hannover »Deutsche Endoprothesenregister gGmbH Past President of the German Society of Ortho- (EPRD)« pedics and Orthopedic Surgery (Deutsche Gesell- Straße des 17. Juni 106–108 schaft für Orthopädie und Orthopädische Chirur- 10623 Berlin gie (DGOOC)), and the German Society for Ortho- paedics and Trauma (Deutsche Gesellschaft für Prof. Dr. Dr. Reinhard Hoffmann Orthopädie und Unfallchirurgie (DGOU)) Secretary General of the German Trauma Society (Deutsche Gesellschaft für Unfallchirurgie (DGU)) Secretary General of the German Society for- Trauma Surgery (Deutsche Gesellschaft für Orthopädie und Unfallchirurgie (DGOU)) Medical Director of the BG Hospital Frankfurt am Main (Unfallklinik Frankfurt am Main gGmbH) Friedberger Landstraße 430 60389 Frankfurt am Main XI List of abbreviations ACCP American College of Chest Physicians DGUV German Social Accident Insurance Deut- ADL Activities of Daily Living sche (Gesetzliche Unfallversicherung) AE German arthroplasty association »Deut- DIMDI German Institute of Medical Documenta- sche Gesellschaft für Endoprothetik e. V.« tion and Information (Deutsches Institut AHB Subsequent rehabilitation (Anschluss- für Medizinische Dokumentation und heilbehandlung) Information) AOK Statutory health insurance (Allgemeine DRG Diagnosis Related Groups Ortskrankenkasse) DRV German Statutory Pension Insurance AQUA- AQUA Institute for Applied Quality (Deutsche Rentenversicherung) Institut Improvement and Research in Health DVT Deep vein thrombosis Care (Institut für angewandte Qualitäts- EBM Uniform Value Scale (Einheitlicher förderung und Forschung im Gesund- Bewertungsmaßstab) heitswesen Institut GmbH) EPRD German joint replacement registry AR Additional remuneration »Endoprothesenregister Deutschland ARCO Association Research Circulation Osseous (EPRD)« ASA American Society of Anesthesiology ESC European Society of Cardiology AWMF Association of the Scientific Medical So- ETM Evidence-based treatment modules cieties in Germany (Arbeitsgemeinschaft (Evidenzbasierte Therapiemodule) der Wissenschaftlichen Medizinischen EULAR European League Against Rheumatism Fachgesellschaften e. V.) FEISA Research and development institute for BÄK German Medical Association (Bundes- social affairs and the healthcare system ärztekammer) in Saxony-Anhalt »Forschungs- und BfArM Federal Institute for Drugs and Medical Entwicklungsinstitut für das Sozial- und Devices (Bundesinstitut für Arzneimittel Gesundheitswesen Sachsen-Anhalt« und Medizinprodukte) G-BA Federal Joint Committee (Gemeinsamer BMG Federal Ministry of Health (Bundes- Bundesausschuss) ministerium für Gesundheit) G-DRG German Diagnosis Related Groups BMI Body Mass Index GKV Statutory health insurance (Gesetzliche BMWi Federal Ministry for Economic Affairs and Krankenversicherung) Energy (Bundesministerium für Wirt- GOÄ Physicians’ fee catalog (Gebührenord- schaft und Energie) nung für Ärzte) BQS Institute for Quality and Patient Safety HIV Human immunodeficiency virus (Institut für Qualität und Patientensicher- HKK Statutory health insurance »Handels- heit GmbH) krankenkasse« BVMed The German Medical Technology Asso- HV Curative procedure (Heilverfahren) ciation (Bundesverband Medizintechno- IC Integrated care logie e. V.) ICD International Statistical Classification of BVOU Professional Association of Orthopaedic Diseases and Related Health Problems Surgeons (Berufsverband der Fachärzte IgeL Individual health services paid for priva- für Orthopädie und Unfallchirurgie e. V.) tely by the patient »Individuelle CC Complications or comorbidities Gesundheitsleistungen« DAH German association for osteoarthritis InEK German Institute for Hospital Reimburse- support »Deutsche Arthrose-Hilfe e.V.« ment »Institut für das Entgeltsystem im DALY Disability Adjusted Life Years Krankenhaus (InEK)« DGOOC German Society of Orthopedics and Or- IQTiG Institute for Quality Assurance and Trans- thopedic Surgery (Deutsche Gesellschaft parency in Healthcare (Institut für Quali- für Orthopädie und Orthopädische tätssicherung und Transparenz im Chirurgie e. V.) Gesundheitswesen) DGOU German Society for Orthopaedics and IQWiG Institute for Quality and Efficiency in Trauma (Deutsche Gesellschaft für Ortho- Health Care (Institut für Qualität und pädie und Unfallchirurgie e. V.) Wirtschaftlichkeit im Gesundheitswesen) DGU German Society for Trauma Surgery IRENA Intensified post-rehabilitation care (Deutsche Gesellschaft für Unfallchirur- (Intensivierte Rehabilitations-Nachsorge) gie e. V.) XII List of abbreviations IV Integrated care (Integrierte Versorgung) VKA Vitamin K antagonist FJC Federal Joint Committee VTE Venous thromboembolism KHEntgG Hospital Remuneration Act (Kranken- WHO World Health Organization hausentgeltgesetz) WidO Research Institute of the statutory KHG Hospital Financing Act (Gesetz zur wirt- health insurance AOK »Wissenschaftli- schaftlichen Sicherung der Krankenhäu- ches Institut der AOK« ser und zur Regelung der Krankenhaus- WIP Scientific institute of the private health pflegesätze) insurances »Wissenschaftliches Institut KSS Score Knee Society Score der Privaten Krankenversicherungen« KTL Classification of therapeutic services WOMAC Western Ontario and McMaster Univer- (Klassifikation therapeutischer Leistun- sities Arthritis Index gen) YLD Years Lived with a Disability LMWH Low-molecular-weight heparin ZE Additional remuneration MDD Medical Device Directive ZLG Central Authority of the Länder for Morbi-RSA Morbidity oriented risk adjustment Health Protection regarding Medicinal scheme (Morbiditätsorientierter Risiko- Products and Medical Devices (Zentral- strukturausgleich) stelle der Länder für Gesundheitsschutz MPG Medical Devices Act (Medizinprodukte- bei Arzneimitteln und Medizinproduk- gesetz) ten) MTPS Mechanical thromboprophylaxis stockings (compression stockings) NICE National Institute for Health and Care Excellence NIH National Institutes of Health NHP Nottingham Health Profile NSA Non-steroidal antiphlogistic drugs NUB New examination and treatment methods »Neue Untersuchungs- und Behandlungsmethoden« OECD Organisation for Economic Cooperation and Development OPS German procedure classification »Opera- tionen- und Prozedurenschlüssel« OTA Surgical technician (Operations- technischer Assistant) PE Pulmonary embolism PROM Patient-Reported Outcome Measures QALY Quality-Adjusted Life Year QSR Quality assurance using routine data (Qualitätssicherung mit Routinedaten) REDIA Rehabilitation and diagnosis-related groups study (Rehabilitation und Diagnosis Related Groups-Studie) RKI Robert Koch Institute SGB Social Security Code (Sozialgesetzbuch) SHI Statutory health insurance ST Surgical Technicians SVR Advisory Council on the Assessment of Developments in the Healthcare System (Sachverständigenrat zur Begutachtung der Entwicklung im Gesundheitswesen) THA Total hip arthroplasty TKA Total knee arthroplasty TK Statutory health insurance (Techniker Krankenkasse) vdek Association of Substitute Health Insu- rance Funds (Verband der Ersatzkassen e. V.) 1 1 Introduction to the Indications and Procedures Cornelia Seidlitz, Miriam Kip 1.1 Definition –2 1.2 Etiology, Indications and Treatment Goals –2 1.2.1 Etiology – 2 1.2.2 Indications – 6 1.2.3 Surgery Goals and Objectives –8 1.3 Materials, Surgical Procedures and Risks –8 1.3.1 Material Requirements – 8 1.3.2 Surgery – 9 1.3.3 Factors Influencing Treatment Success and Complications – 10 References – 13 © The Editor(s) (if applicable) and The Author(s) 2018 H.-H. Bleß, M. Kip (Eds.), White Paper on Joint Replacement DOI 10.1007/978-3-662-55918-5_1 2 Chapter 1 · Introduction to the Indications and Procedures Summary The most common reason for joint replace- 1 Arthroplasty is defined as the surgical replacement of ments is joint surface destruction from wear of the a joint with artificially produced material. Total ar- cartilage lining due to degenerative diseases such as throplasty refers to the replacement of all joint sur- osteoarthritis, fractures and other changes in bone faces concerned, while partial replacement involves and connective tissue structures. Under certain cir- the replacement of only one or some of the surfaces cumstances, these can lead to permanent loss of but not the entire joint. Hip and knee joints are those function, permanent pain and impaired mobility of that are most frequently replaced. The most common the affected joint, as well as a decrease in quality of indications for hip or knee arthroplasty are sympto- life. If these symptoms cannot be treated otherwise, matic osteoarthritis and femoral neck fractures (hip). replacement with an artificial joint becomes neces- When patients undergo hip or knee replacement for sary in order to avoid secondary complications and the first time (due to osteoarthritis) they are usually to restore the patient’s ability to participate ade- between 60 and 70 years of age. More than two quately in everyday life. thirds of patients who undergo arthroplasty due to The causes and consequently also the risk of re- femoral neck fractures are over 85 years of age. Pri- quiring joint replacements are largely dependent on mary arthroplasty refers to the first hip or knee re- age. On average, patients are aged between 60 and placement and revision arthroplasty refers to fol- 70 years when they receive an artificial hip or knee low-up surgery on the same joint. The period of time joint replacement for the first time. (without complications) between primary arthroplas- ty and revision arthroplasty is termed as »service life«. In symptomatic osteoarthritis, arthroplasty is 1.2 Etiology, Indications performed after all conservative and joint preserving and Treatment Goals therapy options have been exhausted. With regard to femoral neck fractures, joint replacement is usually 1.2.1 Etiology the primary treatment option. Surgery aims to im- prove the quality of life, to restore the greatest possi- Symptomatic osteoarthritis constitutes the most ble functionality, mobility and freedom from pain, to common reason for requiring hip joint replacement assure a long service life with good weight-bearing (Claes et al. 2012; Wirtz 2011). Over 80 % of all pri- capacity and to avoid secondary complications. mary hip surgery is due to osteoarthritis-related These constitute important prerequisites for leading symptomatic degenerative changes in the articular an independent life in old age. surfaces (osteoarthritis of the hip) (Barmer GEK 2010). Other reasons include periarticular fractures, such as femoral neck fractures (Strohm et al. 2015), 1.1 Definition chronic inflammatory rheumatic diseases, mis- alignments and pathological changes of the bone Arthroplasty is defined as the essential surgical re- substance, due to tumors for example, metastases or placement of a joint with artificially produced ma- osteoporosis, which increase the risk of periarticu- terial which is fixated in the bone (joint replace- lar fractures (Claes et al. 2012). ment, endoprosthetic surgery, alloarthroplasty) In the majority of cases, osteoarthritis also con- (Claes et al. 2012; Wirtz 2011). Total replacement stitutes the main reason for requiring knee joint refers to the replacement of all the joint surfaces replacement (osteoarthritis of the knee). Osteo- concerned while partial replacement involves the arthritis is responsible for 96 % of all primary endo- replacement of only one or some of the surfaces but prosthetic procedures on the knee (Barmer GEK not the entire joint. Hip and knee joints are the most 2010). Other reasons for knee joint replacements are frequently replaced, but endoprosthetic implants much less frequent (Wirtz 2011). are also used to replace other joint functions, such as shoulder or elbow joints (Claes et al. 2012; Wirtz 2011). 1.2 · Etiology, Indications and Treatment Goals 3 1 . Tab. 1.1 Osteoarthritis classification and risk factors (selection) Classification Risk factors Description Primary localized (hip, knee) or generalized (polyosteoarthritis, more than (idiopathic) three joint regions affected) Secondary congenital and acquired joint e.g. hip dysplasia, malalignments of the knee defects endocrine diseases e.g. diabetes mellitus metabolic disorders e.g. hemochromatosis, hypercholesterolemia, hyperuricemia posttraumatic e.g. following joint fractures, fractures near the hip, cruciate liga- ment injury in the knee other causes e.g. sepsis, inflammatory rheumatic disease, circulatory disorders of the bone near the joint in avascular necrosis of the femoral head and femoral condyle Source: IGES – Günther et al. 2013 jOsteoarthritis Osteoarthritis is characterized by an imbalance Numerous potential risk factors for osteoarthri- in the cartilage metabolism in which catabolic pro- tis-related joint changes exist (. Tab. 1.1). If these cesses prevail. Cartilage degeneration initially leads risk factors cannot be clearly ascertained, the osteo- to the formation of new less resistant cartilage tis- arthritis is classified as primary or idiopathic. In sue. Therefore, joint function is restored but the contrast, secondary osteoarthritis has one or more joint is less resistant to strain. Over time, the carti- identifiable risk factors that may contribute to the lage tissue can be completely destroyed and the advancement of the disease. General risk factors in- exposed bone underneath becomes deformed and clude age, sex as well as genetic, biomechanical and the joint thickens (Claes et al. 2012). inflammatory factors. In addition body weight, os- In the advanced stage (active osteoarthritis) the teoporosis, cardiovascular and metabolic diseases increasing destruction of cartilage tissue and conse- can also negatively affect cartilage metabolism. Risk quent inflammation of the synovial membrane lead factors resulting in local effects include injuries, cir- to acute episodes of pain, movement restriction, culatory disorders, congenital or acquired malfor- swelling, joint warmth and sensations of tension. mations and too much strain on only one side of the Sensitivity to weather, heat and cold are also typical joint. As a result, multicausal rather than mono- symptoms during this phase. Generally, this stage of causal explanatory models are therefore generally the disease can last several years and can include favored nowadays (Günther et al. 2013). phases with and without symptoms (Claes et al. The main symptoms of osteoarthritis are pain 2012) (. Fig 1.1). and increased restriction in mobility of the affected During the late stage of the disease (decompen- joints. In most cases, the disease usually progresses sated osteoarthritis), the progressive destruction of chronically, initially with symptoms such as joint the joint is accompanied by permanent pain and stiffness which at first only occur after a longer pe- functional restrictions. This leads to diminished riod of strain on the affected joint. At first, pain only quality of life in patients as daily life activities (e.g. occurs following certain movements or after longer washing, getting dressed) and mobility are affected. periods of rest (pain on initial movement). At a later Pain then occurs during minor movements or even stage, the pain is not associated with strain and be- at rest. Chronic pain can also develop, caused by comes continuous (resting pain, nocturnal pain) cartilage destruction, sclerosis and the formation of (Claes et al. 2012). bone projections (osteophytes) as well as damage to 4 Chapter 1 · Introduction to the Indications and Procedures 1 60 51.9 Population 18+ years (%) 50 40 36.1 32.3 19.7 30 27.8 Women 26.1 23.8 Men 20 Total 9.2 8.9 10 2.7 1.9 0 18–29 30–44 45–64 65+ Total Age (years) . Fig. 1.1 Lifetime prevalence of osteoarthritis in Germany in 2012. (IGES – RKI 2014) adjacent structures such as bones, muscles, capsules (Ewerbeck and Dreinhofer 2009) together with esti- and ligaments. Osteoarthritis can ultimately lead to mates from the German Society for Orthopaedics stiffness and instability of the affected joints result- and Trauma (Deutsche Gesellschaft für Orthopädie ing in immobility of the patient and consequently in und Unfallchirurgie e. V.) (DGOU)) (Schmitt 2014) the development of severe secondary diseases (Claes based on demographic trends and disease burdens et al. 2012). give reason to expect an increase in these age-relat- According to the Robert Koch Institute (RKI), ed diseases the future. An increase in the number of the lifetime prevalence of osteoarthritis in Germany heavily overweight people in the population consti- in 2012 was 27.8 % in women and 19.7 % in men. tutes another influencing factor that will play an There was a noticeable rise in the prevalence of the important role with regard to knee joint replace- disease in older age groups: In the 30 to 44 years age ments (Derman et al. 2014). group, 9.2 % of the women surveyed and 8.9 % of men reported to have osteoarthritis, in the 45 to 64 jFemoral neck fracture years age group, 32.3 % and 26.1 % respectively re- Besides osteoarthritis, another important risk factor ported to have osteoarthritis as did approximately for hip joint replacement is the femoral neck frac- 50 % all women and 36 % of men who were older ture. It gains growing importance with increasing than 65 years of age (. Fig. 1.1). Previous studies patient age (Claes et al. 2012; Strohm et al. 2015). have shown that the prevalence of symptomatic os- Femoral neck fractures are close to the joint and teoarthritis in the population is estimated to be require surgical treatment in most cases. Conserva- around 10 % in people over 60 years of age (Sun et tive therapy is only possible in cases of stable, al. 1997). non-impacted fractures. The surgical procedures Due to the expected future demographic trends available include procedures that preserve the joint in Germany, a significant rise in degenerative joint and endoprosthetic procedures. The procedure se- diseases and therefore in hip and knee osteoarthritis lected will depend on the type of fracture and the requiring treatment can be expected (RKI 2009). age of the patient, amongst other factors. Usually, an Corresponding estimates for the increased needs of endoprosthesis is implanted in patients over 65 endoprosthetic care for other countries (Culliford et years of age and in patients already suffering from al. 2015; Kurtz et al. 2007) cannot be directly applied joint osteoarthritis (Pfeifer et al. 2001). Osteosyn- to Germany. However, prognoses published in rela- thetic procedures aim to preserve the joint with the tion to the development in musculoskeletal diseases help of locking nails, cannulated screws or dynamic 1.2 · Etiology, Indications and Treatment Goals 5 1 hip screws consisting of extramedullary plates and femoral neck fractures will also rise (Berufsverband antirotation screws (Claes et al. 2012). der Fachärzte für Orthopädie e. V. 2004, Pfeifer et al. The most common causes of femoral neck frac- 2001). Given the current demographic trends in Eu- tures are falls that occur at home which in turn can rope, it is assumed that the incidence of femoral be ascribed to underlying diseases, for instance neu- fractures will increase by at least fourfold over the rological or heart diseases. next 60 years. A femoral neck fracture is one of the most com- To date, only limited data from studies on the mon late-stage complications of osteoporosis incidence of femoral neck fractures in Germany is (Stöckle et al. 2005). The prevalence of osteoporosis available. An epidemiological investigation based amongst the over 50 age group is approximately on hospital statistics from 2004 found an incidence 14 % (women: 24 %; men: 6 %) (Hadji et al. 2013). of 140.9 per 100,000 inhabitants. In correlation with Factors which contribute to femoral neck frac- the age-dependency, the incidence in older popula- tures include age-related reduced bone mineral tion groups (over 65 years) was significantly higher density and a higher risk of falling. Risk factors for (662 per 100,000 inhabitants as opposed to 21.7 per falls include vitamin D deficiency (which affects the 100,000 inhabitants in groups aged below 65 years) muscles), coordination disorders (for example due and was also significantly higher in women than in to medication), dizziness, defective vision, weak- men (Icks et al. 2008). ness, multimorbidity or existing diseases of the According to the latest hospital diagnoses data, musculoskeletal system. The average age of patients the number of inpatient cases in 2013 was 144 per with femoral neck fractures is relatively high and 100,000 inhabitants (age standardized). The num- hence rapid mobilization is particularly important ber of cases in the over 65 years of age group was at in order to avoid further complications. Preserva- 875 cases per 100,000 inhabitants and as expected, tion of the femoral head is given primary impor- women were affected more than twice as often as tance solely in younger patients (Claes et al. 2012). men (. Fig. 1.2). Femoral neck fractures in younger patients are rare and are usually the result of so-called high-en- jFemoral head necrosis ergy traumas, i.e. road traffic accidents and falls In femoral head necrosis the bone tissue of the fem- from great heights. Additionally, malignant diseases oral head dies (osteonecrosis). This is a result of is- that are accompanied by bone destruction can also chemia (circulatory disorder) of the affected area lead to femoral neck fractures (pathological frac- (Meizer et al. 2007). tures). Inadequate blood supply can result from trau- Femoral neck fractures are associated with se- matic factors (posttraumatic osteonecrosis), such as vere pain in the hip region, restricted mobility of the tearing or overstretching following a femoral neck hip joint and on walking. Often, the affected leg is fracture, or various different risk factors and under- noticeably shorter and rotated outwards. External lying diseases (nontraumatic osteonecrosis). There signs of injury include hematomas or swelling above are several different risk factors and underlying dis- the hip joint. In cases of impacted fractures, clinical eases which can lead to nontraumatic osteonecrosis. signs can be very discrete in that patients may still Identifiable risk factors which are observed in 50 % be able to walk for several days despite the fracture to 80 % of cases include alcohol and nicotine abuse, (Claes et al. 2012). dyslipidemia, pregnancy and hereditary coagula- The risk of femoral neck fractures in one’s life- tion disorders such as thrombophilia. In addition, time is indicated to be between 11 % to 23 % in high-dose corticosteroid intake (for example, for women and 5 % to 11 % in men (Stöckle et al. 2005). chronic inflammatory diseases) is associated with a This incidence rises with increasing age with a high risk of disease development. Diseases that have marked increase from the age of 74 years in particu- been observed to result in higher rates of femoral lar (RKI 2009). Consequently, with a steadily in- head necrosis include systemic lupus erythemato- creasing proportion of older people in the popula- sus, HIV, malignancies, and inflammatory bowel tion, it can be assumed that the absolute number of diseases, amongst others. 6 Chapter 1 · Introduction to the Indications and Procedures 1 Case numbers per 100,000 persons (2013) 900 800 700 600 500 400 300 200 100 0 0–14 15–44 45–64 65+ Total Women Men Age (years) . Fig. 1.2 Inpatient case numbers per 100,000 inhabitants with a femoral fracture (S72) by age group and by sex (age- standardized) (2013). (IGES – Federal Statistical Office 2014) Symptoms associated with femoral head necro- days to several years (ARCO classification) (AWMF sis vary greatly between individuals and are non- 2014). specific (Hofmann et al. 2002). Particularly at the In German-speaking countries, the incidence of start of the disease, which advances bilaterally in femoral head necrosis is estimated at 0.01 %, which 30 % to 70 % of cases, there may initially be no corresponds to approximately 5,000 to 7,000 pa- symptoms such as pain on weight bearing or diffi- tients a year (Hofmann et al. 2002). The disease oc- culty walking. During the later stage, femoral head curs mainly between the ages of 25 and 55 years with necrosis leads to movement restrictions and strong a peak at 35 years of age. Men are affected four times recurrent hip pain radiating into the thigh and knee. as often as women. According to a routine data With the progression of the disease, pain at rest may analysis conducted by the Barmer GEK, bone ne- also occur and in the final stages of the disease os- crosis was indicated as the relevant main diagnosis teoarthritis of the hip with complete destruction of upon discharge in approximately 3 % of primary the joint may occur (AWMF 2009b). total hip arthroplasty (THA) cases (Barmer GEK Early diagnosis of femoral head necrosis is cru- 2010). cial to joint-preserving treatment and improved long-term prognosis. In 85 % of patients, the disease will progress within two years if the initial diagnosis 1.2.2 Indications is left untreated and results in femoral head collapse with complete destruction of the joint in over half of jPrimary arthroplasty the patients (Hofmann et al. 2002). Based on the The indication for a hip or knee replacement is criteria developed by the Association Research Cir- based on patient-relevant clinical and radiological culation Osseous (ARCO), idiopathic femoral head criteria together with a thorough examination of the necrosis (without any known cause) is categorized patient’s medical history (Claes et al. 2012, Wirtz into five different stages (0 to IV). The progression 2011). of each stage varies greatly between individuals and The clinical diagnosis includes an examination the duration can also vary from a period of several of the affected joint as well as of the structures and 1.2 · Etiology, Indications and Treatment Goals 7 1 tissue surrounding the joint. It also includes func- jRevision arthroplasty tional tests and pain assessments, for example, de- Revision arthroplasty entails the removal and re- termining how far the patient can walk free of pain. placement of one or more components of the hip or The mobility of the joint can only be assessed by knee endoprosthesis. It is therefore a follow-up sur- clinical examination. In addition, pain and other gical procedure for primary hip or knee arthroplas- complaints can be evaluated by means of standard- ty that is performed on the same joint. ized patient surveys (AWMF 2009a, 2008; Claes et Follow-up surgery without replacement or re- al. 2012; Wirtz 2011). moval of the (entire) artificial joint can also be per- Besides objective criteria, a patient’s degree of formed if the endoprosthesis is not functioning en- suffering and his or her requirements at the time of tirely correctly (EPRD 2015), for example to remove the examination play a substantial role in the deci- a hematoma (revision without replacement). The sion for or against replacement of the affected joint. time between primary replacement and t revision is For instance, a replacement should not be recom- termed as »service life« (EPRD 2015). mended if the radiological findings show a joint af- Usually, revision arthroplasty is performed after fected by osteoarthritis but the patient does not have the »natural« service life of the endoprosthesis has osteoarthritis-related symptoms or does not have come to an end. In some cases, however, earlier revi- many complaints (AWMF 2009a, 2008; Claes et al. sion replacement might become necessary. Reasons 2012; Wirtz 2011). for revision arthroplasty include loosening of the According to Claes et al. (2012), an indication implant, instability of the artificial joint, extensive for a hip joint replacement exists if a patient’s qual- bacterial infections and progressive degeneration of ity of life is severely affected by pain or functional parts of the joint that have not yet been replaced. impairment. Additional factors include conserva- Revision can also become necessary if functional tive therapies that are insufficiently effective (medi- impairments of the artificial joint severely restrict a cation, avoiding strain on the affected joint, physio- patient’s activities and are often accompanied by therapy, physical therapy, etc.) as well as visible pronounced pain. Additionally, acute or chronic in- causative radiological changes such as morphologi- fections as well as traumatic fractures close to the cal joint damage, which cannot be treated conserva- joint or the endoprosthesis as well as problems with tively (Claes et al. 2012). Furthermore, indications the implant and the primary replacement procedure for hip joint replacements exist for patients over the may make revision replacement necessary. Other age of 60 years who have femoral neck fractures and reasons include local inflammatory tissue reactions, in patients with femoral fractures due to pathologi- wear (micro-abrasive particles) of the endopros- cal bone diseases (for example metastases, osteopo- thetic material and the quality of the endoprosthesis rosis) (Claes et al. 2012). fixation. Patient compliance and characteristics According to Wirtz (2011), an indication for to- such as age or weight also have a significant impact tal knee arthroplasty (TKA) in primary and second- on the endoprosthetic service life (Section 1.3.3). ary osteoarthritis of the knee exists if the conditions Documented arthroplasty in the German joint are associated with severe pain and movement im- replacement registry »Endoprothesenregister pairments which can be confirmed radiologically Deutschland (EPRD)« will enable a reliable deter- (Wirtz 2011). Both the European League Against mination of the service life in future, which can be Rheumatism (EULAR) and the US National Insti- related to the different levels of care such as to the tutes of Health (NIH) consider the indication for a surgeon, the hospital performing endoprosthetic knee joint replacement to exist if, alongside the ra- surgery, the individual endoprosthesis and the type diological evidence of osteoarthritis, a patient has of endoprosthesis depending on the initial docu- continuous pain that is not manageable with drugs, mentation. or if the disease is accompanied by substantial func- tional impairments (EULAR 2002, NIH 2004). 8 Chapter 1 · Introduction to the Indications and Procedures 1.2.3 Surgery Goals and Objectives Meanwhile, many different variations of these 1 artificial joints exist. Therefore, a short overview of Primary arthroplasty aims to restore joint function how they function and the most important features as much as possible, to reduce pain caused by osteo- is provided in the following paragraphs. arthritis (hip or knee) and by other diseases. It also Nowadays, hip endoprostheses usually consist aims to rapidly mobilize patients after femoral neck of an acetabular cup and a femoral stem onto which fractures. A further goal is to achieve a long service a modular endoprosthesis head is attached. The cup life with good weight-bearing capacity and to avoid may consist of one piece (usually polyethylene) or of (secondary) complications. On the whole, a pa- a metal cup with an inlay (modular cup). Frequent- tient’s quality of life should be improved and their ly, fractures in elderly people are treated by solely mobility enhanced (Claes et al. 2012; Wirtz 2011). replacing the femoral head with a so-called hemien- Mobility is a basic prerequisite for leading an inde- doprosthesis without replacing the cup. In this case, pendent life and preserving patients from social a (usually modular) head which has the size of the isolation, especially in older age groups (Moon natural femoral head is attached to the endopros- 2014). thetic stem. Special procedures such as surface re- placements are of minor relevance for hip joints (Claes et al. 2012). 1.3 Materials, Surgical Procedures Parts of the knee joint or the joint surface are and Risks replaced by bowl-shaped implants on the femoral side and a tibial baseplate, which can be fixated into 1.3.1 Material Requirements the medullary cavity with or without a stem. The bearing surface between the femur and the tibia can Ideally, the primary endoprosthesis should be re- be connected with the baseplate or be mobile and tained over a lifetime. Despite tremendous technical gliding. The back of the patella may be replaced with advances and the availability of high-quality mate- an implant (Wirtz 2011). rials, this cannot be achieved for all patients. In gen- The contact surface between the bone and im- eral, both hip and knee endoprostheses are weight plant is of great importance for weight bearing on bearing body parts and must be designed accord- the joint after surgery. This connection technique is ingly, also with regard to the material selected (Claes generally referred to as fixation. An implant can be et al. 2012, Wirtz 2011). fixated with or without bone cement – combined The implants undergo extensive testing with solutions are termed hybrid fixation or partial ce- regard to functionality, quality, reliability and safety mentation. The applied bone cement is a special which constitutes a prerequisite for statutory prod- artificial cement (polymethylmethacrylate). Unce- uct requirements. Corresponding requirements can mented endoprosthesis components can have a spe- be found in international standards which are re- cial surface design or coating (e.g. titanium specifi- viewed every five years (BVMed 2014). cations or hydroxylapatite) in order to support sec- Regardless of the field of application, implants ondary bone ingrowth. Primary stable fixation is must have the longest possible durability which why achieved by fixing the endoprosthesis to the bone is hard-wearing materials with minimal wear even (so-called press-fit) (Claes et al. 2012; Wirtz 2011) when used in combination with other materials are with the aim of permanently attaching the endopros- employed. In addition, the materials must be ac- thesis to the bone bed. Opinions on the advantages cepted by the body as there is risk of potential rejec- and disadvantages of cemented an uncemented fixa- tion. It is recommended that metals (such as cobalt- tion vary and the choice of procedure depends on chromium and titanium alloys) be used which are different factors (such as age and bone quality) (see connected to the bone and tribologically paired Section 1.3.3) (Claes et al. 2012, Wirtz 2011). with synthetic materials (polyethylene) or ceramics (NICE 2014). 1.3 · Materials, Surgical Procedures and Risks 9 1 1.3.2 Surgery hemiarthroplasty or partial arthroplasty. An exam- ple of this is the dual head prosthesis, which is par- Prior to surgery the physician informs the patient of ticularly used in cases of femoral neck fractures in any possible complications and risks. Specific treat- elderly patients (Claes et al. 2012). ment planning includes selecting the appropriate The accuracy of the endoprosthetic fit is tested endoprosthesis based on clinical and radiological regularly by means of a trial prosthesis while the criteria as well as deciding on the surgical access joint is being surgically prepared. The surgeon must route (. Fig. 1.3). ensure that there is enough tension on the ligaments In hip arthroplasty, the natural structures of the and the soft tissue for the artificial joint to glide and pelvis and the upper leg are usually replaced, i.e. the to avoid dislocation. The implantation of the actual acetabulum in the pelvis and part of the femoral shaft endoprosthesis is performed either with or without as well as the femoral head in the upper leg. When all bone cement. Subsequently, the surgical access these structures are replaced, the procedure is re- route is closed. The position of the endoprosthesis ferred to as total replacement or total arthroplasty. is checked by x-ray immediately after surgery (Claes Total arthroplasty also includes short stem femoral et al. 2012). head prostheses, which are usually used in younger Special care must be taken when positioning the patients, as well as surface replacement prostheses. patient during arthroplasty. Cushioning materials If the acetabular cup does not need replacing, are used to prevent pressure points on the patient the procedure is termed as partial replacement, and warming systems are used to prevent hypother- Preliminary Follow-up treatment Surgical planning examinations planning (Digital) planning of the bio- Medical history and clinical mechanics of the hip joint prosthesis examinations including gait, and the prosthetic components, Mobilization, leg length, range of motion of taking into account individual use of medical aids the hip joint, perhaps additional patient particulars functional tests (e. g. bone defects) Selection of the implant (type, size, tribological pairing) and the fixation technique (hip shaft, cementation) Prophylaxis: Pelvic x-ray taking into account individual Thrombosis, ossification patient particulars such as allergies to certain materials (allergy test if necessary) Selection of the surgical access To exclude existence of other route (minimally invasive, diseases of the spine and adjacent conventional) and corresponding Follow-up X-ray joints, via MRT scans if necessary positioning of the patient or by infiltration of the hip joint (supine, lateral) . Fig. 1.3 Elements of treatment planning based on hip arthroplasty. (IGES – Wilken et al. 2014) 10 Chapter 1 · Introduction to the Indications and Procedures mia. The patient can be placed in a lateral or supine holders are used allowing the leg to be positioned in 1 position. It is important to accurately secure the pa- an upright 90 degree position (Wirtz 2011). tient in the selected position with the help of props Numerous studies on various surgical access and straps in order to avoid any changes in position routes for both the hip and the knee joint exist. during the surgery (Claes et al. 2012). However, no significant advantage in any one of the In knee arthroplasty, parts of the upper leg (dis- particular procedures has been shown. Less invasive tal femur) and the lower leg (proximal tibia) are re- access routes have been advocated in recent years, as placed with artificial material. Different types of they reduce the extent of tissue incision. However, implants are used depending on the nature and se- actual clinical effectiveness is a matter of debate and verity of the underlying disease. Structures that are they may also bear a higher risk of complications. In usually replaced include portions of the femoral hip revision surgery, for instance, the initial access bone (femoral component) to substitute the defec- route used during primary surgery is often used tive condyle as well as parts of the lower leg around again. Additionally, these procedures require more the tibial plateau (tibial component) and the me- extensive imaging of tissue and bone structures nisci. The patella may or may not be replaced. A (Claes et al. 2012; Wirtz 2011). synthetic component is placed on the tibial compo- nent in order to minimize friction between the tib- jAnesthesia ial and femoral components (»inlay«) (Wirtz 2011). Two anesthetic techniques can be used for both en- Unicondylar surface replacement, i.e. on one doprosthetic hip and knee surgery: general anesthe- side of the joint only, is possible if knee function is sia and regional anesthesia. General anesthesia re- not yet severely impaired by cartilage abrasion and quires artificial ventilation and is based on anxioly- the bone is affected on only one side of the knee sis, analgesia, muscle relaxation and sedation. Un- joint. Usually, the medial (inner) side is replaced. der certain circumstances, regional anesthesia, in Besides the structure of the cartilage and bone, the which the patient is conscious, may also be used in condition of the ligaments is also crucial to decision the form of spinal anesthesia or by blocking periph- making. Unilateral surface replacement is often eral nerves or regions with a single injection or by termed unicompartmental knee replacement using continuous application by means of a catheter. Gen- a unicondylar sled prosthesis that may also be re- eral and regional anesthesia can be used alone or in ferred to as sled prosthesis or mono-sled (Wirtz combination. Anesthesia aims to allow for pain-free 2012). surgery, rapid mobilization after surgery and as Bicondylar and hinge prostheses are used for much pain reduction as possible in the early reha- total knee arthroplasty. Here, the degree of coupling bilitation phase (Claes et al. 2012, Wirtz 2011). is an important distinguishing factor. Hinge pros- theses are axially supported. Usually, this type of prosthesis is selected if the ligamentous apparatus is 1.3.3 Factors Influencing Treatment severely impaired because the hinge significantly Success and Complications restricts mobility. However, surface replacement prostheses without coupling or with partial cou- A number of factors can influence the success of pling are used more frequently. A prerequisite for joint replacement treatment (. Fig. 1.4). Besides the using these types of endoprosthesis is sufficient design of the implant and surgical procedure, a pa- functionality of the patient’s ligamentous apparatus. tient’s individual characteristics can impact total hip The artificial knee is often fixated with bone ce- and knee arthroplasty outcomes. These characteris- ment, but uncemented or hybrid fixation is also fea- tics include age, sex, degree of preoperative osteo- sible (Wirtz 2011). arthritis and functional status of the joint in ques- Positioning during knee arthroplasty is designed tion. Additionally, concomitant diseases (particu- to allow frequent changes in position of the leg as larly obesity, cardiovascular diseases, diabetes mel- specific steps during treatment require the extremi- litus and immune system disorders) can lead to ties to be mobile. Therefore, rolls and special leg perioperative and postoperative complications. 1.3 · Materials, Surgical Procedures and Risks 11 1 Patient Treatment Functionality and disability Perioperative and postoperative measures – Functional and structural integrity or – Patient education and information damage (e. g. degree of osteoarthritis, – Anaesthesia mobility) – Perioperative prophylaxis (infection, DVT, etc.) – Limitations in daily activities and social – Rehabilitation (medical/occupational) participation (e. g. tasks, mobility, self- – Follow-up examinations sufficiency) Clinic pathw al ays Contextual factors Implant – Personal environment (e. g. aids and – Endoprosthesis (and cement if necessary) medical appliances, social relationships) – Individual factors (e. g. age, personal issues or problems, comorbidity) Surgeon – Surgical access and technique – Experience – Communication Result . Fig. 1.4 Factors influencing treatment success. (IGES – Günther et al. 2015) Social deprivation, personality traits and patient flammation (infection) because pathogens expectations with regard to the surgery also play an (bacteria) that enter the body or that already influencing role (Günther et al. 2015; Schäfer et al. exist therein tend to accumulate on the surface 2010). Patient compliance, i.e. the degree to which a of foreign bodies. Once a certain number of patient correctly follows medical advice with regard bacteria have accumulated, pus may begin to to daily care of the joint, constitutes a further impor- develop around the implant. These infections tant factor in the success of joint replacement. can occur shortly after the operation (»early Optimal presurgical planning is important, in- infection«) or later (»late infection«). The risk cluding investigation into risk factors of a patient of infection can vary between different patient that are potentially modifiable. Well-planned post- groups. Patients with diseases associated with a operative rehabilitation treatment (ambulatory or weakened immune system in particular bear a inpatient rehabilitation) contributes to treatment higher risk of infection. These diseases include success (Claes et al. 2012; Wirtz 2011) and plays an diabetes mellitus and rheumatic diseases. Mo- important role in attaining longer service life of an reover, patients who have a focus of infection implant, high patient satisfaction and cost-effective- in other parts of the body or who suffer from ness (Krummenauer et al. 2008; Krummenauer et obesity have a higher risk of infection. The risk al. 2006). of infection is reduced through the administra- Arthroplasty procedures are associated with po- tion of antibiotics during surgery. tential risks caused by surgical and anesthetic 4 Blood clots (thrombosis and embolism): The procedures in general or with the insertion of the im- formation of blood clots constitutes a general plant itself. Joint replacement can involve the follow- risk in surgery of the knee and hip joints. ing major risks (Anonymous, Günther et al. 2015): Antithrombotic drugs are recommended for 4 Inflammation and suppuration (periprosthetic the prevention of thrombosis. infection): Artificial joint replacements are al- 4 Nerve damage: During surgery, inadvertent ways associated with an increased risk of in- damage to the nerves may occur through phy- 12 Chapter 1 · Introduction to the Indications and Procedures sical manipulation such pressure or tension in early replacement of the prosthesis becomes 1 the regions concerned. Regional anesthesia necessary due to loose fit. Particulate wear may also cause nerve damage. Congenital hip debris may be released during the course of dislocation also constitutes a risk factor as the prosthesis use, which can contribute to loose- leg may become over extended during hip joint ning of the implant. However, given the quality surgery. of materials currently in use there is only a 4 Injury of blood vessels and postoperative blee- slight risk of such an abrasion occurring and ding: Surgery on the hip or knee joint is gene- hence individual prosthesis components rarely rally associated with the risk of injury to blood break for this reason. However, if they do vessels close to the joint. Moreover, despite break, it is usually due to loosening of the adequate hemostasis, postoperative bleeding prosthesis. may occur due to antithrombotic therapy. 4 Allergies: Even though it is still currently 4 Leg length inequality and dislocations consti- unclear if allergies to parts of the prosthesis tute specific risks during hip joint replacement: increase the risk of complications, specific When hip joints are replaced, the aim is to materials in the prosthesis should be avoided achieve equal leg lengths. However, the opera- should a patient be allergic to them. About tion may lead to a lengthening and sometimes 10 % of the population is allergic to nickel, for even a shortening of the affected leg. In addi- example. tion, there is a risk of dislocation subsequent to 4 Persisting complaints: Besides the complica- surgery as on the one hand, the implant is not tions described, bursitis or tendonitis, for an identical copy of the joint and on the other example, may cause persisting complaints hand, the surgical procedure involves opening following surgery. This, however, has been and partially removing the stabilizing joint observed in comparatively few patients. capsule. 4 Fractures: Necessary pressure exerted during Repeat surgery or revision replacement may be- the course of this type of surgery may cause come necessary due to complications. Replacing an fractures in rare occasions. The risk of frac- implant is considerably more complicated than the tures is higher for in uncemented fixation as primary replacement (primary arthroplasty) as the this requires higher pressure during insertion. surgeon has to deal with less bone substance there- 4 Calcification in the tissue near the prosthesis: fore increasing the likelihood of fractures and other During the first few months following surgery, complications. A patient may also have to undergo calcification may occur within the surgical revision surgery in which the prosthesis is not re- wounds which can lead to reduced mobility placed or in which only a component is added to the and pain. Administration of anti-inflammatory existing endoprosthesis (renewed operation with drugs for two weeks after surgery is recom- addition). These revisions are usually performed on mended in order to prevent this. Alternatively, the hip and knee to replace the bearing surfaces and irradiation of the affected region is possible. to manage recurring hip dislocations. However, dis- 4 Loosening of the prosthesis and material wear: locations may also necessitate the replacement of an It is rare for the prosthesis not to have success- implant should this occur repeatedly (Claes et al. ful bone ingrowth. If the case should arise, 2012; Wirtz 2011). References 13 1 Open Access This chapter is published under the Creative Commons Attribution NonCommercial 4.0 International license (http://creativecommons.org/licenses/by-nc/4.0/deed.de) which grants you the right to use, copy, edit, share and reproduce this chapter in any medium and format, provided that you duly mention the original author(s) and the source, include a link to the Creative Commons license and indicate whether you have made any changes. 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ISBN: 978-3-89606-196-6. https:// www.rki.de/DE/Content/Gesundheitsmonitoring/Gesund- heitsberichterstattung/GBEDownloadsB/alter_gesund- heit.pdf?__blob=publicationFile [accessed: 04 November 2015]. 15 2 Prevalence of Hip and Knee Arthroplasty Florian Rothbauer, Ute Zerwes, Hans-Holger Bleß, Miriam Kip 2.1 Database – 16 2.2 Utilization of Primary Arthroplasty – 19 2.3 Utilization of Revision Total Arthroplasty and Revision Surgery – 21 2.4 Regional Distribution – 23 2.5 Case Number Developments – 26 2.5.1 Primary Arthroplasty – 26 2.5.2 Revision Total Arthroplasty and Revision Surgery – 29 2.6 International Comparison – 31 References – 39 © The Editor(s) (if applicable) and The Author(s) 2018 H.-H. Bleß, M. Kip (Eds.), White Paper on Joint Replacement DOI 10.1007/978-3-662-55918-5_2 16 Chapter 2 · Prevalence of Hip and Knee Arthroplasty Summary destruction or pain which can no longer be treated The annual rate of primary hip and knee arthroplasty otherwise. They are also used to treat fractures near has not increased since 2007. In the 70 years plus age the joint. The different types of arthroplasty pro- 2 group, the rate of primary hip arthroplasty was 1.1 % cedures aim to restore good joint function, (in both 2007 and 2014) and the rate of primary knee weight-bearing capacity and quality of life. The arthroplasty was 0.7 % in 2007 and 0.6 % in 2014. prevalence (utilization) of arthroplasty is an impor- In 2014, the prevalence of surgery in relation to the tant aspect for planning ambulatory and inpatient entire population was 0.26 % for the hip and 0.19 % care, as well as for estimating demands and subse- for the knee. Approximately 219,000 primary hip quent demands such as rehabilitation measures and replacements and 149,000 primary knee replace- questions with regard to resource allocation. The ments were documented in Germany in 2014. The following chapter presents the utilization hip and most common procedure performed on a joint was knee arthroplasty services in Germany and differen- total replacement. Approximately 40 % of all primary tiates these according to age and gender, type of hip or knee replacements are performed in patients procedure and fixation technique. The presentation in the 70 to 79 year age group; women are more fre- distinguishes between primary and revision arthro- quently affected than men (ratio 2:1). In 2014, the plasty. Furthermore, this chapter investigates re- absolute number of revisions (including revisions gional differences in distribution of these medical without replacements) amounted to approximately care services and in temporal developments with 30,000 for the hip and 20,000 for the knee. The num- regard to their utilization in Germany and compares ber of revisions performed in any given year is not these internationally. necessarily directly related to the number of primary replacements performed in the same year. Instead, the number of revisions should be considered in rela- 2.1 Database tion to the cumulative number of primary replace- ments performed over the past years and decades. The German procedure classification »Opera- As with primary arthroplasty, approximately 40 % of tionen- und Prozedurenschlüssel (OPS)« enables the revisions are performed on patients in the 70 to detailed observations of the annual inpatient prima- 79 years age group. However, the difference between ry and revision hip and knee replacements per- men and women is less pronounced. formed in Germany. In the German healthcare Between 2007 and 2014, the rate of hip and knee system, the OPS is primarily used for administrative revision replacements (including revision without purposes to identify the services rendered to inpa- replacements) also remained stable. In 2014, in the tients. 70 years plus age group, the rate of revision replace- Bone and joint replacements are classified in ments (including revision without replacements) was Section 5-82 of the OPS (. Tab. 2.1). The coding 0.19 % for the hip and 0.10 % for the knee. The annu- system allows for reliable distinctions to be made al utilization rate of primary hip and knee arthroplas- between primary arthroplasty, revision, revision to- ty varies internationally. Regional differences also tal arthroplasty and the removal of hip joints (5- exist within Germany itself, as evaluations conducted 820/5-821) and knee joints (5-822/5-823). In addi- by the statutory health insurances for the period tion, age and sex of patients are specified. OPS 5-820 from 2005 to 2011 have shown. A comparatively low and 5-822 document primary endoprosthetic care utilization rate was associated in particular with low (primary arthroplasty) for hip and knee joints re- incidences of osteoarthritis, low social status, a high spectively. OPS 5-821 and 5-823 and further differ- number of regional specialist physicians (orthope- entiated sub-codes refer to revision surgery, i.e. revi- dists) and patients living in urban areas. sion total arthroplasty and revisions (follow-up surgery and re-revisions) on joints that have already Hip and knee arthroplasty constitute effective treat- undergone previous endoprosthetic surgery. ments for patients with substantial (or impending) permanently restricted joint function due to joint 2.1 · Database 17 2 . Tab. 2.1 OPS classification OPS description OPS description Hip: Primary arthroplasty 5-820.0 Total arthroplasty 5-820.2 Total arthroplasty, custom-made prosthesis 5-820.3 Femoral head prosthesis 5-820.4 Dual head prosthesis 5-820.5 Acetabular support cup 5-820.7 Acetabular liner locking cup 5-820.8 Surface replacement 5-820.9 Short-stem femoral head prosthesis 5-820.x Other 5-820.y Unspecified Hip: Revision total arthroplasty and revision 5-821.0 Revision (without replacement) 5-821.1 Femoral head prosthesis replacement 5-821.2 Acetabular cup replacement 5-821.3 Revision cemented total arthroplasty 5-821.4 Revision uncemented total arthroplasty 5-821.5 Revision total arthroplasty, hybrid endo- prosthesis 5-821.6 Revision total arthroplasty, custom-made 5-821.7 Total endoprosthesis removal prosthesis 5-821.8 Femoral head prosthesis removal 5-821.9 Dual head prosthesis removal 5-821.a Femoral head cap removal 5-821.b Acetabular cup removal 5-821.c Acetabular support cup removal 5-821.d Acetabular liner locking cup removal 5-821.e Total endoprosthesis removal, custom- 5-821.f Dual head prosthesis replacement made prosthesis 5-821.g Surface prosthesis replacement 5-821.h Surface prosthesis removal 5-821.j Femoral neck preserving femoral head 5-821.k Femoral neck preserving femoral head prosthesis (short-stem femoral head prosthesis (short-stem femoral head prosthesis) replacement prosthesis) removal 5-821.x Other 5-821.y Unspecified Knee: Primary arthroplasty 5-822.0 Unicondylar sledge prosthesis 5-822.1 Bicondylar surface prosthesis, uncon- strained, without patella replacement 5-822.2 Bicondylar surface prosthesis, uncon- 5-822.3 Bicondylar surface replacement prosthe- strained, with patella replacement sis, partially constrained, with patella replacement 5-822.4 Bicondylar surface prosthesis, partially 5-822.6 Hinged endoprosthesis, without patella constrained, without patella replacement replacement 5-822.7 Hinged endoprosthesis, with patella 5-822.8 Patella replacement replacement 5-822.9 Custom-made prosthesis 5-822.a Endoprosthesis with enhanced flexion, without patella replacement 5-822.b Endoprosthesis with enhanced flexion, 5-822.c Interpositional non-anchored implant with patella replacement 5-822.d Bicompartmental replacement, without 5-822.e Bicompartmental replacement, with patella replacement patella replacement 18 Chapter 2 · Prevalence of Hip and Knee Arthroplasty . Tab. 2.1 OPS classification OPS description OPS description 2 5-822.f Implantation of an endoprosthetic joint 5-822.x Other without movement function 5-822.x 5-822.y Unspecified Knee: Revision and replacement operation 5-823.0 Revision (without replacement) 5-832.1 Unicondylar sledge prosthesis replacement 5-823.2 Bicondylar sledge prosthesis replacement 5-823.3 Hinged endoprosthesis replacement 5-823.4 Custom-made prosthesis replacement 5-823.5 Patella prosthesis replacement 5-823.6 Unicondylar sledge prosthesis removal 5-823.7 Bicondylar surface prosthesis removal 5-823.8 Hinged endoprosthesis removal 5-823.9 Patella prosthesis replacement 5-823.a Custom-made prosthesis removal 5-823.b Replacement of an endoprosthesis with enhanced flexion 5-823.c Replacement of an interpositional non- 5-823.d Removal of an endoprosthesis with anchored implant nhanced flexion 5-823.e Removal of an interpositional non-an- 5-823.f Bicompartmental prosthesis replacement chored implant 5-823.g Bicompartmental prosthesis removal 5-823.h Replacement of endoprosthetic joint without movement function 5-823.j Removal of an endoprosthetic joint with- 5-823.x Other out movement function 5-823.y Unspecified Source: IGES – DIMDI (2015) The German Federal Statistical Office (Statis- tients. The Federal Statistical Office dataset also tisches Bundesamt) makes OPS data publicly avail- does not portray connections to underlying indica- able as is stipulated by § 21 of the German Hospital tions (osteoarthritis, fractures and other causes). Remuneration Act. Only case-based and not pa- Although hospitals report connections between tient-based data can be accessed. Consequently, the diagnoses and procedures to the respective health number of cases does not (necessarily) correspond insurances and the German Institute for Hospital to the number of patients. Two-stage surgery is Reimbursement (InEK), combining this data pub- documented as two separate cases and subsequently licly is not possible. Moreover, further clinical pa- individual patients may be counted multiple times. rameters required for describing indications such as The Federal Statistical Office dataset does not pain, joint function or quality of life are not depict- permit statistical evaluations of the surgical access, ed. Connections with indications and procedures, endoprosthetic material or of whether the surgery for example, will be made possible in the future was planned or had to be performed as an emer- through the German joint replacement registry gency. Determining the durability of the endo- »Endoprothesenregister Deutschland (EPRD)« prostheses (service life) is also not possible as no (7 Chapter 4). As the risk of having to undergo joint connection can be made between the actual implan- replacement is not uniformly spread across all pop- tation and prosthesis removal for individual pa- ulation and age groups, reliable statements about 2.2 · Utilization of Primary Arthroplasty 19 2 9.0% Partial joint replacement uncemented 22.1% (n=19,016) Partial joint replacement cemented 17.7% (n=37,170) Total arthroplasty uncemented (n=107,727) Total arthroplasty cemented (n=46,432) OPS 5-820*, n total = 210,384 51.2% . Fig. 2.1 Distribution of hip joint arthroplasty utilization (n = 210,384) (OPS 5-820.*) by total and partial replacement and fixation technique (2013). (IGES – Federal Statistical Office 2014) the differences in prevalence (for example, in re- ment (Federal Statistical Office 2014) (. Fig. 2.1). In gional and international comparisons) can only be 2014, the rate of surgery in the general population made after adjusting or standardising the respective (as determined on 31 December 2014) was 0.26 % databases for influencing characteristics such as age (own calculation, Federal Statistical Office 2014, or sex. Regional evaluations of health insurance data Federal Statistical Office 2015). (for example by Schäfer et al. 2013; Lüring et al. The absolute number of primary knee arthro- 2013) usually report prevalence rates that are stan- plasties was 149,126 in 2014 and 143,024 in 2013. dardized to population structures. Furthermore, 84 % of the 143,024 primary knee arthroplasties consistent survey methods should be employed to performed in 2013 were bicondylar replacements ensure good reliability for making comparisons. (. Fig. 2.2). The rate of knee replacement surgery in Presentations of patient-related OECD data that the total population (as determined on 31 Decem- internationally compare prevalences of endopros- ber 2014) was 0.19 % in 2014 (own calculation, Fed- thetic hip and knee surgery usually do not take these eral Statistical Office 2014, Federal Statistical Office aspects into sufficient consideration (7 Chapter 6). 2015). In contrast to primary hip arthroplasty, the majority of primary knee arthroplasties (79.6 %) were fixated with cement. Entirely uncemented 2.2 Utilization of Primary fixation was documented in 10.5 % of all operations Arthroplasty and hybrid/partially cemented fixation was docu- mented in 9.6 % of the primary replacements (Fed- According to data from the Federal Statistical Of- eral Statistical Office 2014). fice, a total of 219,325 primary hip arthroplasties In the age group of over 60-year-olds, well over were performed in 2014 and 210,384 in 2013 (abso- 65 % of primary hip or knee replacements were per- lute numbers). Out of the 210,384 primary hip ar- formed in women (Federal Statistical Office 2014). throplasties performed in 2013, 154,159 (73.3 %) A higher proportion of female hip and knee arthro- were total arthroplasties (THA) and 56,225 (26.7 %) plasty patients has also been well documented else- were partial arthroplasties. 60.2 % (126,743 cases) of where (Braun 2013; Lüring et al. 2013). The higher all hip endoprostheses were implanted without ce- percentage of female patients is due to the higher 20 Chapter 2 · Prevalence of Hip and Knee Arthroplasty 0.4% 0.3% 0.9% 2 13.5% 9.2% 9.6% TKA cemented (n=94,466) TKA uncemented (n=13,723) 66.0% TKA hybrid (n=13,141) Partial replacement cemented (n=19,318) Partial replacement uncemented (n=1,304) Partial replacement hybrid (n=617) Other (incl. non-anchored) (n=455) . Fig. 2.2 Distribution of primary knee arthroplasty utilization (absolute number, n = 143,024) (OPS 5-822.*) by total and partial replacement and fixation technique (2013). (IGES – Federal Statistical Office 2014) 35,000 30,000 25,000 Number 20,000 15,000 10,000 5,000 0 10-14 15-19 20-24 25-29 30-34 35-39 40-44 45-49 50-54 55-59 60-64 65-69 70-74 75-79 80-84 85-89 90-94 95+ 1-4 5-9 Age (years) Hip: Total arthroplasty Hip: Partial replacement Knee: Total arthroplasty Knee: Partial replacement . Fig. 2.3 Utilization (absolute number) of primary hip and knee arthroplasty by total and partial replacement and age group (2013). (IGES – Federal Statistical Office 2014) 2.3 · Utilization of Revision Total Arthroplasty and Revision Surgery 21 2 prevalence of osteoarthritis in women (most com- . Tab. 2.2 Utilization (absolute number) of revision mon indication for hip or knee arthroplasty) in ad- total replacements and revisions on the hip and knee dition to a significantly longer life expectancy for (2013) women (Rabenberg 2013). Primary surgery is clearly associated with patient Description Prevalence age: Approximately 40 % of all primary hip or knee Hip joint n % replacements documented in Germany are per- Total arthroplasty formed in the 70 to 79 year age group (. Fig. 2.3). In 2013, the average age at the time of the primary total Revision total arthroplasty 4,537 14.6 hip or knee arthroplasty was 69.7 and 69.2 years (uncemented) respectively. Patients who underwent partial knee Revision total arthroplasty 2,325 7.5 replacement were slightly younger on average (mean (cemented) age 65.8 years). In contrast, the highest number of Revision total arthroplasty (partially 871 2.8 patients who underwent partial hip replacement was cemented) observed in the 85 to 89 year age group. This age Custom-made prosthesis replace- 837 2.7 group has more documented cases of primary partial ment hip replacements than of total hip replacements. Partial replacement This is primarily due to the high prevalence of fe- moral neck fractures which occur particularly often Acetabular cup component replace- 12,473 40.1 ment in this age group and are predominantly treated with partial replacements (Section 1.2.1 and Section 1.2.2) Femoral head prosthesis replacement 4,859 15.6 (. Fig. 2.3) (Federal Statistical Office 2014). Dual head prosthesis replacement 941 3.0 There is also a link between patient age and the Surface prosthesis replacement 221 0.7 employed fixation technique: The proportion of ce- mented total hip arthroplasties (THA) increases Femoral neck preserving femoral 219 0.7 head prosthesis replacement with age in comparison to uncemented THA (Fed- eral Statistical Office 2014). Revision (without replacement) 3,784 12.2 Revision total arthroplasty and 31,067 100 revisions, total 2.3 Utilization of Revision Total Knee n % Arthroplasty and Revision Bicondylar surface prosthesis 11,290 55.4 Surgery Unicondylar sledge prosthesis 2,317 11.4 According to the Federal Statistical Office, a total of replacement 35,133 revision hip arthroplasties were performed Hinged endoprosthesis replacement 1,222 6.0 in 2014 and a total of 31,067 revision hip arthroplas- Endoprosthesis with enhanced 699 3.4 ties and 21,678 revision knee arthroplasties were flexion replacement performed in 2013 (including revisions without re- Custom-made prosthesis replacement 533 2.6 placements) (absolute numbers). In 2014, this cor- responded to a prevalence of surgery of 0.04 % (hip) Bicompartmental prosthesis 459 2.3 replacement and 0.06 % (knee) respectively in the general popu- lation (as determined on 31 December 2014) (own Patella replacement 439 2.2 calculation, Federal Statistical Office 2014, Federal Other 212 1.0 Statistical Office 2015). 3,784 cases and 3,213 cases Revision (without replacement) 3,213 15.8 were revisions without component replacements on the hip and the knee respectively. Accordingly, revi- Total 20,384 100 sions without replacements accounted for approxi- Source: IGES – Federal Statistical Office (2014) mately 12 % and 16 % of all documented hip and 22 Chapter 2 · Prevalence of Hip and Knee Arthroplasty 6,000 5,000 2 4,000 Number 3,000 2,000 1,000 0 + 4 4 9 9 4 9 9 4 4 9 4 9 4 9 9 4 4 4 9 -2 -5 -1 -5 -6 -7 -8 -8 -1 -2 95 -3 -3 -4 -4 -6 -7 -9 1- 5- 20 50 15 55 60 75 85 80 10 25 30 35 40 45 65 70 90 Age (years) Knee: Revision arthroplasties, total Hip: Revision total arthroplasties Hip: Revision partial replacement . Fig. 2.4 Utilization of revision arthroplasty (absolute number) including revisions without replacements by type and age group (2013). (Source: IGES – Federal Statistical Office 2014) Revision THA Revision partial replacement, component revision (hip) Revisiion (without replacement) (hip) Revision TKA Revision partial replacement, component revision (knee) Revisio on (without replacement) (knee) on 0 2,000 4,000 6,000 8,000 10,000 12,000 Number Male Female . Fig. 2.5 Utilization (absolute number) of joint replacement procedures on the hip and knee by type of revision replace- ment (including revisions without replacements) and by sex (2013). (Source: IGES – Federal Statistical Office 2014) 2.4 · Regional Distribution 23 2 knee replacements respectively which were con- authors calculated age-standardized surgery rates ducted in one year (2013). Replacements of acetab- (primary hip or knee arthroplasty per 100,000 insu- ular cup components (partial replacement) or of rees per year). Only total arthroplasties were taken bicondylar surface prostheses were the most com- into account. Age-standardized rates (European mon revision replacements performed on the hip standard) were calculated in order to minimize dis- and the knee respectively (. Tab. 2.2) (Federal Sta- tortions arising from demographic differences be- tistical Office 2014). tween the regions and to enable comparisons be- In 2013, the highest number of revision total tween regions and other studies (Schäfer et al. 2013). arthroplasties and revisions (partial replacements) In 2009, a total of 148 primary hip replacements were performed in the 75 to 79 year age group. 40 % and 132 primary knee replacements per 100,000 of all revision total arthroplasties and revisions on AOK insurees was performed. Marked differences the hip and knee were performed in the 70 to 79 year were observed at federal state levels: The lowest rate age group. In 2013, the average age of patients who of hip replacements was documented in Berlin with underwent revision total arthroplasty and other re- 120 operations and the highest in Lower Saxony vision surgery on the hip was 72.5 years and 69 years with 168, corresponding to a difference of approxi- for those who underwent revision total arthroplasty mately 40 % (. Fig. 2.6). The rate of knee replace- and other revision surgery on the knee. These aver- ments showed equally distinct regional variations at age ages are slightly higher than the average ages of federal state level (78.4 %): The lowest rate of re- patients who undergo primary surgery (. Fig. 2.4) placement was again observed in Berlin (90) and the (Federal Statistical Office 2014). highest number of primary TKAs in the study pop- As with primary arthroplasty, the absolute num- ulation was observed in Bavaria (160). Upon solely ber of revision total arthroplasties and revisions is evaluating federal area states and excluding federal higher in women than in men. Considering that the city states, the lowest rates of hip replacements can absolute number of primary replacements in men is be observed in Saxony-Anhalt (143) and the lowest markedly lower than in women, men undergo com- rate of knee replacements in Mecklenburg-Western paratively more revisions and revision total replace- Pomerania (109). The highest are observed in Ba- ments (. Fig. 2.5). varia, Lower-Saxony and Schleswig-Holstein and However, a direct link between the number of Thuringia (Schäfer et al. 2013). revision total replacements and primary replace- The AOK evaluation also demonstrated major ments in a certain year cannot be ascertained. The differences at district levels. The lowest hip arthro- number of revision total replacements should be plasty rate (average value for the period between considered in relation to the cumulative number of 2005 and 2009) was 106 cases (in the district Neus- primary replacements performed over the past tadt an der Weinstraße) and the highest rate was 216 years and decades because endoprostheses have cases per 100,000 insurees (in the district Neustadt long mean service lives. 7 Chapter 6 presents expert an der Aisch). The regional differences for TKA opinions on the different aspects of evaluating the were also higher than for hip procedures at district prevalence of revision replacements (including revi- levels (Schäfer et al. 2013). sions without replacements). The German Society for Orthopaedics and Trauma (DGOU) published a report on behalf of the foundation »Bertelsmann Stiftung« describing 2.4 Regional Distribution the regional differences and influencing factors on knee arthroplasty. This report also describes dis- The regional distribution of hip and knee arthro- tinct regional differences for knee arthroplasty pro- plasty across the German federal states and districts cedures (. Fig. 2.7). The evaluation was also based was evaluated by Schäfer et al. based on accounting on accounting data from AOK insurees but these data (secondary data) of patients insured with the were obtained from the period between 2005 and statutory health insurance AOK. This included 24 2011. This investigation also found that in 2011, million insurees from the years 2005 to 2009. The age-standardized utilization of knee replacement 24 Chapter 2 · Prevalence of Hip and Knee Arthroplasty Age-standardized arthroplasty rates per 100,000 persons 180 160 2 140 120 100 80 60 40 20 0 y rg ria n g en rg Po -W e Lo era ern ny ia e nd ny lt n a an gi ss at rli ei ur ha al be bu xo xo va em w nia la in st He tin Be m est ph nb rm An ar m Ba m ol Sa Sa ur Br la st de Sa Ge y- tte -H Ha Th Pa er e n an ig g -W ür xo d- ur w Br W e an Sa nb es in n- el hl Rh kle de in Sc rth ec Rh Ba M No Federal state . Fig. 2.6 Age-standardized primary hip arthroplasty rates per 100,000 AOK insurees in 2009. (Source: IGES – Schäfer et al. 2013) 180 30% 160 25% Surgery rate per 100,000 persons 140 120 20% Percentage 100 15% 80 60 10% 40 5% 20 0 0% y rg ria de n g en g Po -W se w an n ny ia e nd ny ny lt Th ein a an gi at rli Lo er ster ur ur ha al be s xo o va em er ia la in st e tin Be an tph nb b rm Sa Sax An H ar m Ba m ol Sa ur m e Br la Sa Ge - tte -H Ha es Pa an ig g W ür xo d- ur w e- Br W nb es in n- el hl Rh kle de in Sc rth ec Rh Ba M No Federal state Age-standardized arthroplasty rates per 100,000 inhabitants, 2011 Rate of increase 2005-2011, % . Fig. 2.7 Age-standardized primary knee arthroplasty rates per 100,000 AOK insurees in 2011, by federal state (patient domic- ile) and as a national average in Germany, with increases of arthroplasty rates, 2005-2011. (Source: IGES – Lüring et al. 2013) 2.4 · Regional Distribution 25 2 Age-standarized rates of revision 25 per 100,000 persons 20 replacements 15 10 5 0 y Ba rg ria de n Br g Ha en rg Po W se w ni n ny Pa alia Sa ate nd ny t ur n a al an gi rli Lo era ter Th ei ur be bu g- es er a xo xo va nh em la in t tin Be h nb rm s m es ur H ar m an tp m ol Sa Sa hl ny-A la Ge tte -H es an ig W ür xo d- w - Br W Rh ine Sa nb es n- el Rh kle de in Sc rth ec Ba M No Federal State . Fig. 2.8 Age-standardized revision knee arthroplasty rates per 100,000 inhabitants, by federal state (patient domicile) and as the national average in Germany (2011). (Source: IGES – Lüring et al. 2013) procedures was highest in Bavaria and lowest in ments on the knee per 100,000 inhabitants in 2011, Berlin. According to the calculations, above-average according to federal states of patient domiciles and increases in rates in the years 2005 to 2011 can be using the national average as a comparison. Revi- observed for patients in the federal states of sion replacements were defined as »any renewed Schleswig-Holstein, Rhineland-Palatinate, Bavaria, surgery on the same knee joint«. Thuringia, Hamburg, Hesse and Berlin (Lüring The analysis shows that in 2011, the highest et al. 2013). numbers of revision knee replacements in relation In the East German regions, the numbers of to the number of inhabitants were performed in both types of joint replacement procedures were Saxony-Anhalt, Thuringia, Bavaria and Lower-Sax- generally below the average value (except Thuringia) ony. Patients in Mecklenburg-Western Pomerania (Schäfer et al. 2013). had the lowest rates of revision. The numbers correlated with the osteoarthritis . Fig. 2.9 clearly demonstrates that surgery rates incidence (prevalence) whereby regions with high in the federal states have in part increased consider- incidences had comparatively higher rates of THAs ably over the past ten years. However, the graph dif- and TKAs. Further variables that could explain the ferentiates between the rates of increase for the pe- regional differences in utilization were local num- riods between 2005 and 2008 and between 2008 and bers of specialist physicians (orthopedists), regional 2011, illustrating that the rise in surgery rates was socioeconomic status and patients living in urban considerably higher in the earlier period than in the areas. The lower the regional number of orthope- later period (with the exception of Bremen). From dists and the higher the socioeconomic status of the 2008, the rates of increase generally tend to be lower population were in a region, the higher the rate of and even show declines in some federal states total arthroplasty procedures amongst insurees liv- (Lüring et al. 2013). ing in that region. Total arthroplasties were per- With this, federal states in the southeast had al- formed considerably less frequently in urban areas most consistently higher rates of surgery than in the than in rural areas (Schäfer et al. 2013). northeast. At district level, the differences are even . Fig. 2.8 shows Lüring et al.«s calculations for more pronounced. With regard to primary replace- age-standardized surgery rates for revision replace- ments, the district with the highest rate of replace- 26 Chapter 2 · Prevalence of Hip and Knee Arthroplasty 120% 100% 2 80% Change (%) 60% 40% 20% 0% -20% Bavaria Rhineland-Palatinate Saxony Saxony-Anhalt Baden-Württemberg Berlin Brandenburg Bremen Hamburg Saarland Schleswig-Holstein Mecklenburg-Western Lower Saxony North Rhine-Westphalia Pomerania Thuringia Germany Hesse Federal state 2005-2008 2008-2011 . Fig. 2.9 Rates of change in age-standardized revision knee replacement rates, 2005-2008 and 2008-2011. (Source: IGES – Lüring et al. 2013) ments had a 2.9-fold higher rate of knee arthroplas- 2.5 Case Number Developments ty than the district with the lowest rate. With regard to revisions, the greatest difference between two 2.5.1 Primary Arthroplasty districts was 4.9-fold (Lüring et al. 2013). The report discusses manifold reasons for the Since 2007, the absolute number of primary hip and differences in prevalence. One aspect is that region- knee arthroplasties has been increasing, which is in al differences in access to hospital care exist. Addi- line with the growing number of older people (risk tionally, a bias is created in that patient domiciles population) in the population. From 2007 to 2014, and the place of surgery are not in the same region. the prevalence of primary hip and knee replace- Additional matters of discussion are revenue struc- ments amongst patients over the age of 70 years (as ture and that the remuneration system may set determined on 31 December in the respective year) wrong incentives and consequently also contribute did not increase and remained stable at 1.1 % for to the regional differences. The authors, however, primary hip replacements (2007 and 2014) and be- emphasize that the observed increasing case num- tween 0.7 % and 0.6 % (2007 and 2014 respectively) bers which are not caused by demographic changes for primary knee replacements (. Fig. 2.10) (own should not solely be attributed to wrong financial calculation, Federal Statistical Office 2014, Federal incentives (Lüring et al. 2013). On the whole, how- Statistical Office 2015). After an increase in the ab- ever, the data is insufficient for establishing causal solute number of primary replacements from 2007 relationships (Lüring et al. 2013). to 2011, the number of hip replacements showed a slight decline from 213,935 cases in 2011 to 210,384 cases in 2013, followed by an increase to 219,325 cases in 2014. In 2009, the number of primary knee replacements was 159,137, which remained almost 2.5 · Case Number Developments 27 2 Prevalence of primary arthroplasty in the population aged 70 plus Hip (OPS 5-820.-) Knee (OPS 5-822.-) 1.20% 1.00% 0.80% 0.60% 0.40% 0.20% 0.00% 2007 2008 2009 2010 2011 2012 2013 2014 . Fig. 2.10 Prevalence of primary hip and knee replacements in the population aged 70 plus (2007 to 2014). (Source: IGES – own calculation, Federal Statistical Office 2014, Federal Statistical Office 2015) unchanged in 2010 and 2011 and subsequently An evaluation of the case number developments declined. In 2013, 7.6 % fewer primary knee re- for primary hip and knee replacements in Germany placements were performed than in 2008 and 10.1 % from 2005 to 2011 showed that the increase in the fewer primary replacements (absolute number) number of primary hip replacements can largely be than during the peak year 2009. ascribed to demographic developments. In contrast, Changes in case numbers over time can be ob- non-demographic factors prevailed with regard to served when examining the utilization of THA with the increase in primary knee replacements (Weng- regard to the fixation technique selected. During the ler et al. 2014). six-year observational period, the number of unce- If case number developments cannot be suffi- mented total arthroplasties (not including custom- ciently explained by the demographic develop- made prostheses) rose by 5 % in absolute numbers. ments, this may be an indication of an existing over- The utilization of cemented procedures decreased supply or shortage of care (Barmer GEK 2010). Be- in the same period: Cemented and partially cement- sides demographics, other factors and their respec- ed total replacements declined by 33 % and 9 % re- tive changes (medical, economic, systemic, Section spectively from 2008 to 2013. Custom-made pros- 2.4) influence the prevalence of utilization of medi- theses only played a marginal role (. Fig. 2.11). cal services over time. Often, these effects cannot be Case numbers for the four most common types sufficiently quantified (7 Chapter 6). of primary knee arthroplasty have been declining over the past few years (. Fig. 2.12). The decline in the number of primary arthroplasties is primarily due to a reduced utilization of cemented total re- placements. 28 Chapter 2 · Prevalence of Hip and Knee Arthroplasty 120,000 2 100,000 80,000 Number 60,000 40,000 20,000 0 2008 2009 2010 2011 2012 2013 Year Total arthroplasty - uncemented Total arthroplasty - hybrid Total arthroplasty - cemented Custom-made prothesis (uncemented, cemented, hybrid) . Fig. 2.11 Absolute number of primary THAs performed, by fixation technique, over time (2008 to 2013). (Source: IGES – Federal Statistical Office 2014) 120,000 100,000 80,000 Number 60,000 40,000 20,000 0 2008 2009 2010 2011 2012 2013 Year Total replacement - cemented Total replacement - uncemented Total replacement - hybrid Partial replacement - cemented Other . Fig. 2.12 Absolute number of primary knee replacements performed, by fixation technique (2008 to 2013). (Source: IGES – Federal Statistical Office 2014)
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