When the knee joint is replaced artificially, the joint-forming surfaces of the upper and lower leg are supplied with prosthesis components so that metal then glides on plastic (total knee endoprosthesis). Alternatively, partial prostheses can also be used (partial joint replacement of the knee).
The main area of application for total knee replacement is arthrosis. Unlike a partial joint replacement of the knee, the wear should affect several parts of the knee joint in the case of a complete joint replacement, i.e. there should not only be wear on the inside, outside or behind the kneecap. Around 170,000 artificial knee joints are currently being installed in Germany, and the trend is rising.
In German orthopedic clinics a variety of innovative methods of treatment are applied to treat arthrosis, with the most radical one being a knee replacement surgery. With the help of the complex therapy orthopedic clinics in Germany provide high efficiency of the surgery.
On the pages of our website German medical group, the best clinics in Europe are presented, which offer treatment of such a disease in the field of orthopedics as arthrosis of the knee joint (knee replacement surgery). endoprosthesis replacement (implantation of artificial prostheses) of the knee, shoulder and hip joints. The German orthopedic centers offer the following methods of the arthrosis treatment:
- endoprosthesis revision after knee replacement
- Endoscopic joint surgery on the knee and shoulder joint
- open surgery on the knee, shoulder, hip and ankle joint
- arthroscopy of the knee joint with the usage of the whole range of arthroscopic techniques (surgery on the meniscus, cartilaginous tissue surgery)
- endoprosthesis replacement
- open surgery for knee replacement
Total Knee Arthroplasty: A Sophisticated Joint Replacement
Endoprosthetics, one of the greatest success stories in orthopedic surgery, has a new problem: exaggerated expectations on the part of the patients, who often hope for a complete regeneration. "An implant can never completely replace natural bone," emphasized Prof. Dr. med. Henning Windhagen, director of the orthopedic clinic of the Hannover Medical School, at the press conference of the German Society for Arthroplasty (AE) on the occasion of its annual congress in Hamburg. Patients should be properly selected and carefully informed, especially before a total knee replacement (TEP) is implanted.
The proportion of younger patients also increases with knee TEPs
The implantation of artificial knee and hip joints is one of the most common procedures in German hospitals and is increasing in absolute numbers due to the demographic development of the population (1). According to data from the Federal Statistical Office, a total of 233,000 patients received hip and 187,000 knee TEPs in 2016. Most of those treated were 55 to 84 years old. However, the proportion of younger patients has increased in recent years: Around 10% of hip TEPs and 8% of knee TEPs are implanted in patients under the age of 55.
Not all patients are satisfied with the implants, especially those with an artificial knee joint. While the satisfaction of patients with hip joint TEP is 95%, it is only 80 to 85% for patients with knee TEP, according to Windhagen. "A knee prosthesis does not make every patient a happy person," emphasized the AE President.
It is not uncommon to complain about restricted movement and pain, which has to do with the complex anatomy of this joint. "The knee joint is guided much more by soft tissue than the hip joint," said Windhagen, and the forms of movement are more complex. A knee is not a pure hinge joint, it rolls, glides and turns outwards and inwards. The thigh bone and tibia head always remain in contact when the knee moves. That is why the implantation of an artificial knee is particularly demanding.
The lifetime of knee TEPs is 15 years
According to a systematic literature review with data from 2005 to 2016, the satisfaction of patients with knee TEP depends primarily on expectations before the procedure, the extent of the improvement in function and the course of pain (2). If correctly indicated, a surgical intervention and a smooth course, such implants can last 10 to 15 years and longer. In registry studies, lifetimes of 97%, 89% and 78% after 5, 10 and 15 years were specified for knee TEPs (3).
The main reasons for early changes are infections, patella complications, incorrect positioning of the endoprosthesis and loosening of the endoprosthesis. There is an increased risk of premature implant failure in patients who are extremely overweight and in concomitant diseases such as gout, diabetes or rheumatism. Dreaded infections of the prosthesis are also more likely to occur if you are overweight or have comorbidities. While the risk of prosthesis infection in younger healthy patients is only 1: 250 (0.4%) according to Windhagen, it is around 10 times higher (4%) in a diabetic and 8% in an overweight diabetic (1 : 12).
Serious complications are rare after knee TEP implantation. According to international data, the intrahospital event rate after endoprosthetic treatment of the knee joint is between 1.5% and 3.9% (3). Vascular injuries occur with a frequency of 0.08% or up to 0.36% (up to 30 days after the procedure), sensory or sensorimotor nerve disorders in 0.2% (acute inpatient stay) to 0.65% of the cases ( 3 months). Peri- and postoperative fractures in bones near the knee occur with a frequency of 0.1% to 7% (3).
As is well known, patients with endoprosthetic interventions on the knee also belong to the high-risk group for venous thromboembolism (VTE). Drug VTE prophylaxis over 11–14 days (with low molecular weight heparins, fondaparinux or NOAK) is recommended (4). In addition, physical measures (thrombosis stockings, intermittent pneumatic compression) can be used. According to the AQUA quality report, the incidence of deep leg and pelvic vein thrombosis and pulmonary embolism in patients with elective knee replacement in 2010 was 0.51% and 0.16% in Germany (3).
Knee Arthroscopy vs. Knee Replacement
Knee repair without cutting the sensitve joint has always been the aim and the desire of the orthopedicians. The realization of this desire has started at the beginning of the 90s. Now it belongs to the very efficient method of knee joint treatment, cruciate ligament, cartilage and meniscus repair. Usually only two small incisions of approximately 3 mm are needed for an arthroscopic operation. Within the arthroscopic procedure the skilled surgeon can assess any damage in the knee joint with the mini camera. The advanced optics used at German orthopedic centers provide the highest precision possible. The cost of such a treatment makes up about 6 000-8 000euro.
However, only the early stages of arthrosis can be treated with the arthroscopic methods. If the knee surgery cannot be avoided, don’t look further than Germany. The German orthopedic surgeons are known all over the world for conducting the most successful knee and hip replacement procedures.
Knee Replacement: The Radical Method of the Arthrosis Treatment
Knee replacement surgery is aimed at replacing the bearing surfaces on artificial implants, which will return motion activity to the limbs. The new parts of the knee are fixed in the femoral bone and shin bone with the help of surgical instruments. In case of the total knee replacement the whole joint is replaced.Together with muscle and other soft tissues the installed implants start to support the axis of the limb, thus restoring its features.
One of the most important components in the treatment of arthritis by means of endoprosthesis is the biocompatibility of an implanted construction with the inner environment of the body. Another important part is age-related changes in the anatomy of the knee joint in men and women. Exactly thanks to such a precautionary approach, his work is appreciated by clients. The German specialists use prostheses, in creation of which the gender differences of the mechanics of the knee joint for the both sexes were taken into consideration. The metal alloy of the medical device includes resistant components: molybdenum, cobalt, and chromium. The sliding surface of the endoprosthesis is made from high-strength plastic material DCM, according to a special pressing technology.
Resurfacing Knee Prosthesis. Partial Knee Replacement
In a partial denture of the knee, certain components of the knee joint are replaced by artificial implants. In contrast to a complete knee prosthesis, however, only parts of the joint are replaced in the partial denture - functioning parts of the knee are thus retained in the partial denture.
Basically, the expert speaks in prostheses to be implanted by an endoprosthesis. Surgery is understandably inevitable for this treatment as damaged or diseased parts of the joint must be removed and replaced with artificial ones.
Depending on how strongly the function of the diseased knee joint is affected, different types of partial dentures are used, the individual condition of the joint is crucial. One of the most commonly used forms of partial denture is the so-called "sled prosthesis". With the aid of this prosthesis, relief can be provided for unevenly damaged cartilage surfaces without immediately replacing the entire knee joint.
Partial prostheses of the knee joint can be used in a variety of diseases, the most common partial denture treated diseases include osteoarthritis, in which the cartilage surfaces of the joints are excessively worn.
Even with joints damaged by advanced arthritis, the use of a prosthesis or partial denture is often necessary.
Partial dentures are now made of high quality materials to allow for optimal durability and compatibility of the implant. As a rule, special alloys are used. Commonly used among other mixtures of cobalt, titanium or chromium. In patients with allergy to certain metals, special alternatives may also be used to minimize an allergic reaction.
Mode of action
The principle of action of the unicondylar joint replacement, also called a sled prosthesis, consists in supplying the arthrosis, which has only been detected on one side, on one side (inside or outside). In this case, only the inside (in 90% of cases) or the outside of the joint (10%) are revealed over a smaller incision than in a complete knee replacement. There, the lower and thigh portions of the prosthesis are then installed on only one side. These are a small metal blade in the area of the thigh and a small plate in the area of the lower leg, which is provided with a movable or non-movable plastic onlay. The advantage of the sled prosthesis is that the procedure is smaller and the patient is thus faster mobile again and that usually lower pain and a lower complication rate are associated with it.
The insertion of a carriage prosthesis is exemplified on the inside. In order to install a medial slide, ie a partial denture for the inside of the knee, only one about 8 cm long cut on the inside of the knee joint is required. Then, assuming that the other cartilage structures are still intact, only the inner upper and lower leg portions are exposed and replaced by prosthetic material. The anchoring can be cemented or cementless. Most of the prostheses are currently implanted cemented. However, there is a trend towards cementless supply.
Prerequisite for slide implantation is, as already mentioned, only one-sided arthrosis with little damage behind the kneecap and an axial deviation in the direction of the built-in carriage. Because in order for an inside slide to be used, the patient must have an axial misalignment in the sense of an O-leg. An overcorrection X-leg direction after installation of the carriage is not desired. It should remain a small malposition.
If a knee joint is replaced by a partial prosthesis, the question of resilience naturally arises for all concerned. This especially for the patients who need a partial denture already at a relatively young age.
Due to the constant progress in medicine and especially in medical technology, today implants can be made that allow the patient a nearly optimal function of the knee joint.
Of course, it takes a certain amount of time before the implant can be loaded after surgery, in addition, a professional support by physiotherapy, especially in the early days is indispensable.
If both surgery and rehabilitation have been completed without complications, even a partial denture in the knee will allow a comfortable life. The burdens of everyday life usually pose no major problems - however, it is of paramount importance that patients seek advice from their doctor in this regard, in order to avoid overburdening.
In the case of an optimally developed treatment even moderate recreational sports such as, for example, Nordic walking, or under certain circumstances also jogging, can be operated even with a partial knee prosthesis. However, this is highly dependent on the degree of damage to the affected knee joint and therefore not possible in all cases, or recommended.
In younger people, the long-term strength of the prosthesis is not guaranteed in some cases until the end of life, even if the prostheses used have become more and more durable over time. This can lead to follow-up operations, which, however, often have to be set only after decades of exposure.
The chances of success of the sled prosthesis are high. It is a successful, quite fast, yet demanding operation. The patient has less pain than with a bicondylar resurfacing and is faster mobile again. However, the revision rate, ie the rate of re-operation of the sled prosthesis in the first ten years, is three times higher than in bicondylar resurfacing. This shows that, on the one hand, it should be very well considered whether joint replacement with a sled prosthesis is really appropriate, and, on the other hand, as scientific studies confirm, surgery should only be performed by a very experienced surgeon.
What are the advantages compared to a full denture?
Partial dentures can be used with so-called "minimally invasive surgical methods". The instruments and prostheses are introduced only by small cuts. Tissue and soft tissue are maximally protected, the blood loss and also the danger of an infection are clearly smaller. The great advantage is that all partial surgical prostheses halve all surgical risks. The procedure itself is technically more sophisticated and more delicate than the implantation of a full denture, but it only takes about 45 minutes. The patient can get up the same day, fully load and move the operated knee. Many patients feel that they can resume their usual activities after only a few weeks. Compared to the total denture, the convalescence time is shortened considerably.
How durable are partial dentures in the knee joint?
The durability of a partial denture is usually between 10 and 15 years. The first two years are critical. When complications occur, then often in this time window. Cause are mostly surgical technical problems. These express themselves, e.g. in pain, because the prosthesis is not sitting properly. When these two years are over, the prosthesis holds 10 years in 95% of the patients, 15 years in 92% and even 25 years in at least 82% of all patients. In the near future, more could do so than the already massive improvements in polyethylene quality in recent years. Significant progress has also been made in surgical techniques: robot surgery supported by computer navigation is on the rise. This will certainly help to make knee joint prostheses even more successful in the future.
In principle, it is advisable to have sufficient advice before using a partial denture in the knee joint and - depending on the possibility - to deal with alternative treatment methods.
If the decision has been made for a partial denture and the implant has already been used, care and proper handling of the joint are still important.
For example, even beyond the rehabilitation phase, special physiotherapeutic exercises should be performed to ensure the function of the prosthesis and to support the entire joint with a strengthened musculature.
In general, the muscles have a major impact on the function of the knee prosthesis, as a strong and healthy muscles can relieve them and thus support.
Of course, the exact exercises should be arranged for safety with trained physiotherapists.
Furthermore, care must be taken to avoid falls or other acts of violence necessarily, since the prosthesis can otherwise be damaged or moved because it does not have the stability of a natural joint in falls etc.
Especially during the rehabilitation phase, patients are often a little unsteady on their feet, so that the risk of falling is not to be underestimated.
For this reason, for example, as a sports activity and training method for the supporting muscles especially the cycling on a stationary device or swimming, since the risk of (fall) injury is low.
Total Knee Replacement
In particularly difficult cases a knee prosthesis replaces the whole joint. A total knee replacement replaces the affected joint with the specially manufactured components, eliminating the damaged bearing surfaces and thus eliminating the source of pain.
After conducting operations (endoprosthesis replacement of different joints, arthroscopy, ligament replacement, operations for restoration of the meniscus and other surgery) the othopedic clinics take a compulsory set of measures for rehabilitation in order to eliminate different effects of the surgical intervention (swelling, pain), and restore the joints.
The average joint replacement cost varies from 9 000 EUR-15 000 EUR and more. The total cost depends on many factors. The price includes, as a rule, an intensive rehabilitation course, guided by an experienced physiotherapist.
Kommt eine gelenkerhaltende Therapie aufgrund der Gelenkzerstörung oder altersbedingten Gründen nicht in Frage und sind die bisherigen konservativen und operativen Maßnahmen (Physiotherapie, Schmerzmedikamente, Gelenkspülungen, etc.) ausgereizt, erfolgt das Einsetzen einer Knie-Totalendoprothese (Knie-TEP).
Oberstes Ziel der Operation ist ein schmerzfreies, stabiles und gut bewegliches Kniegelenk, wobei die natürliche Beinachse wiederhergestellt wird. Die in den letzten Jahrzehnten ständig verbesserten Operationstechniken und Implantate machen diesen Eingriff zu einer der häufigsten und erfolgreichsten Routineoperationen (europaweit ca. 150.000/Jahr) in der orthopädischen Chirurgie.
Bikondyläre Prothesen ersetzen die Gelenkoberflächen des inneren und äußeren Gelenkanteils unter weitgehendem Erhalt der körpereigenen Bandstrukturen. Ober- und Unterschenkelanteil sind nicht mechanisch miteinander verbunden. Sind die Bandstrukturen geschädigt kann durch eine zapfenartige Verbindung beider Komponenten eine Stabilisierung des Gelenkes auch bei fehlenden Bändern erreicht werden. Die früher vielfach gebräuchlichen achsgeführten Knieendoprothesen verzichten, unter Resektion großer knöcherner Anteile, gänzlich auf den Erhalt der patienteneigenen Bandstrukturen. Diese Prothesen kommen nur in Ausnahmefällen zur Anwendung.
Die einzelnen Prothesentypen gibt es in verschiedenen Größen; mit Hilfe der präoperativen Planungsskizze werden Modellgröße und Fixation der Prothese bestimmt, wobei hier individuelle Bedürfnisse berücksichtigt werden (Alter, Geschlecht, Knochenform, Körpergewicht, etc.). Anhand der Planung werden auch die Achsen des Beines vermessen und die Prothese in ihrer Ausrichtung geplant.
Bei der Implantation unterscheidet man verschiedene Fixationstechniken: Die zementierte Knie-TEP ist weltweit der Goldstandard. Hierbei werden die Implantate mit antibiotikahaltigem Zement im Knochen fixiert. In seltenen Fällen kann auch eine zementfreie „press-fit“ Verankerung durchgeführt werden. Abhängig von der Fixation bestehen die Komponenten entweder aus Titan oder einer Chrom-Kobalt- Legierung. Als Gleitpartner zwischen den ersetzten Oberflächen wird ein Polyethylen-Einsatz (Inlay) ein-gebracht.
Gelenkersatzoperationen werden ausschließlich unter stationären Bedingungen durchgeführt. Zur Gewährleistung eines optimalen Operationserfolges erfolgt eine frühzeitige postoperative Mobilisation mit Hilfe der Krankengymnastik, wobei abhängig von den erwähnten Implantationstechniken meist eine sofortige Belastung des operierten Beines erlaubt wird. Zum Schutz des Weichteilgewebes müssen für 4-6 Wochen Unterarmgehstützen verwendet werden.
Für den überwiegenden Teil der Patienten schließt sich nach einem Klinikaufenthalt von ca. 7-10 Tagen ein 3-wöchiger Rehabilitationsaufenthalt an. Im Rahmen regelmäßiger, engmaschiger ambulanter Kontrolluntersuchungen werden die Fortschritte der Patienten dokumentiert und ggf. eine ambulante Fortsetzung der mobilisierenden Therapie verordnet.
Gelenkersatz und Sport
Verbunden mit einer schweren Kniegelenkarthrose ist eine deutliche Einschränkung sportlicher Aktivitäten. Die durch den Gelenkersatz erzielte Beschwerdefreiheit lässt den Wunsch nach teilweiser Rückkehr zum Sport aufkommen. International besteht Einigkeit, dass zumindest so genannte „low-impact“ Sportarten, wie Fahrradfahren, Schwimmen, Segeln, Tauchen, Golf und Kegeln unterstützt werden können. Bedingt möglich sind Sportarten wie Tennis, Basketball und Skilaufen. Vermieden werden sollten Kontaktsportarten (Fußball, Handball, etc). Die Empfehlung zu einer bestimmten Sportart ist auch abhängig von dem Leistungsstand des Patienten. Als Faustregel gilt, dass vor der Operation beherrschte Sportarten wieder durchgeführt werden dürfen.
Types оf Knee Replаcement Implаnts
The lаst 10 years witnessed the increаsed number оf knеe replаcement surgeries. Abоut 500 000 of such оperаtiоns аre perfоrmed in Germany аnnuаlly. The аrtificiаl knee jоint is due tо replаce the dаmаged pаrts оf the knee jоint. The аim оf knee replаcement surgery is perfect mоdeling оf the implаnt. The better the аrtificiаl jоint is pоsitiоned, the less mаteriаl аbrаsiоn аrises, which prоlоngs the durаbility оf the prоsthesis.
Usuаlly the knee replаcement implаnts cоnsist оf three prоsthetic pаrts: the twо implаnt pаrts аnd а rоtаting surfаce mаde оf speciаl biоcоmpаtible pоlyethylene mаteriаl. The typicаl knee replаcement implаnts substitute the end pаrts оf the femur (thigh bоne) аnd tibiа (shin bоne). The pоlyethelene pаrt is put between them tо prоvide the smооth rоtаtiоn.
The knee replаcement implаnts prоduced in Germаny аre designed tо fоllоw the cоntоur оf eаch pаtient’s unique knee аnаtоmy, which guаrаntees the mаny yeаrs оf service. The size оf the prоsthetic pаrts is defined individuаlly. А speciаl digitаl X-rаy befоre surgery аnd 3/D mоdeling prоcedures give the surgeоn infоrmаtiоn аbоut the аpprоpriаte size оf the knee jоint prоsthesis.
Generаlly, there аre twо clаssic designs оf the cоmplete knee resurfаcing implаnts: sliding аnd fixed knee systems. The technicаl difference is in this cаse in the mоbility оf the sliding surfаce cоmpоnent. The brаnd аnd design оf the knee replаcement implаnts used by yоur dоctоr оr hоspitаl depends оn mаny fаctоrs, including yоur needs, bаsed оn yоur аge, weight, аctivity level, аnd heаlth.
The knee replаcement implаnt cоmpоunds аre designed sо thаt metаl pаrts аlwаys аlign with plаstic оnes, which аllоw tо eliminаte the weаr.
- Pоsteriоr-stаbilized knee replаcement implаnts
- Cruciаte-retаining knee replаcement implаnts
- Unicоmpаrtmetаl implаnts (pаrtiаl knee replаcement surgery)
The pоsteriоr stаbilized (PS) tоtаl knee replаcement implаnts presuppоse the intercоndylаr femоrаl bоne extrаctiоn priоr tо the implаnt inserting. It mаkes the cruciаte substituting implаnt designs less spаring аnd thus less аpeаling.
If the X-rаy exаminаtiоn shоws thаt оnly оne cоmpаrtment оf the knee is dаmаged (either the mediаl оr lаterаl) а mоre spаring surgery might be the better оptiоn.
Оne аlsо differs between fixed beаring knee replаcement implаnts аnd the mоbile-beаring prоsthesis (knee replаcement implаnt). In the first cаse the pоlyethylene pаrt оf the tibiаl cоmpоnent is аttаched firmly tо the metаl implаnt beneаth. The yоunger pаtients get mоbile-beаring knee replаcement. In this cаse the pоlyethylene pаrt cаn rоll inside the metаl tibiаl compound. Cоmpаred with fixed-beаring implаnt mоdels, the mоbile-beаring knee replаcement implаnts need better suppоrt оf the ligаments аrоund the knee. If the ligаments аre nоt strоng enоugh, mоbile-beаring pаrts cоuld dislоcаte, which is аn indicаtiоn fоr surgicаl revisiоn.
Cemented versus uncemented knee replаcement implаnts
Twо types оf fixаtiоn аre used stаbilize the knee replаcement implаnts. The cemented fixаtiоn uses а fаst-curing bоne cement, which reliаbly fixes the implаnt tо the bоne structures. Cementless fixаtiоn relies оn new bоne grоwing intо the surfаce оf the implаnt. The Germаn speciаlist mаy аlsо use hybrid type оf knee replаcement implаnt fixаtiоn.
It meаns thаt the femоrаl pаrts аre inserted withоut the cement аnd the оther pаrts (the tibiаl аnd the pаtellаr оnes) аre inserted with the cement. Yоur speciаlist in Germany will perfоrm аll the necessаry exаminаtiоns in оrder tо decide whаt kind оf fixаtiоn wоuld be mоre аpprоpriаte аnd reliаble in yоur individuаl cаse.
The use оf cоmputer nаvigаtiоn during оperаtiоns оn endоprоsthesis аllоws tо аchieve the fоllоwing results:
- The lоngevity оf the prоsthesis is increаsed (due tо prоper instаllаtiоn)
- Nо risk оf оf incоrrect pоsitiоning оf the prоsthesis
- Intrаоperаtive mоnitоring оf bоne resectiоn
- Intrаоperаtive mоnitоring аlignment оf the prоsthesis
- Preоperаtive аnd pоstоperаtive cоntrоl оf the cоnditiоnоf sоft tissue structures (ligаments). The visuаlizаtiоn in reаl-time gives аn оppоrtunity tо оbtаin аll the necessаry pаrаmeters оf the instаllаtiоn оf the prоsthesis
The price fоr tоtаl knee replаcement implаntаtiоn (pоsteriоr-stаbilized knee replаcement implаnts оr cruciаte-retаining knee replаcement implаnts) mаkes up аbоut 9 000-15 000 eurо. The pаrtiаl knee replаcement cоsts аbоut 7 000- 9 000 eurо. These аre the аverаge prices including the implаnt design cоst аnd the medicаl services. Usuаlly the pаtient needs аbоut 2-3 weeks rehаbilitаtiоn cоurse tо heаl аfter the surgery аnd get bаck tо аctive life style. The rehаbilitаtiоn cоurse stаrts аlmоst immediаtely аfter the surgery.
We wоuld be glаd tо cоnsult yоu оn аll the issues, cоncerning the knee replаcement implаnts аs well аs methоds аnd cоsts оf implаntаtiоn.
Why to Come to Germany For Knee Replacement?
According to the Orthopedic Institute in Berlin 98 percent of people who have undergone a knee replacement can stay active and forget about pain. The success rates of knee replacement in Germany are second to none. The safety of the procedure and the accuracy during the knee replacement are achieved due to the modern systems of computer navigation. According to the recent study, the risk of complications is twice as high at the US clinics than in Germany.
Explore Germany for the safe and efficient treatment of knee problems! If you are looking for highly-qualified help of an orthopedist, an experienced surgeon in Germany, then contact our company German medical group. We will help you choose among a wide variety of medical services efficient treatment based on the European quality standards.
The satisfaction of patients with knee TEP depends primarily on pre-procedure expectations, extent of functional improvement and pain progression.
Endoprosthetics, one of the greatest success stories of orthopedic surgery, has a new problem: exaggerated expectations on the part of patients, who often hope for complete recovery. "An implant can never completely replace the natural bone", emphasized Prof. Dr. med. med. Henning Windhagen, Director of the Orthopedic Clinic of the Hannover Medical School, at the press conference of the German Society for Endoprosthetics (AE) on the occasion of its annual congress in Hamburg. Patients should be properly selected and carefully informed, especially before implantation of a total knee replacement (TEP).
Proportion of younger patients is also increasing in knee TEPs
The implantation of artificial knee and hip joints is one of the most frequent interventions in German hospitals and is increasing in absolute terms due to the demographic development of the population (1). According to data from the Federal Statistical Office, in 2016 a total of 233,000 patients received hip replacement and 187,000 one knee replacement. Most of those treated were 55 to 84 years old. However, the proportion of younger patients has increased in recent years: about 10% of hip TEP implantations and 8% of knee TEPs occur in patients under 55 years of age.
However, not all patients are satisfied with the implants, especially those with an artificial knee joint. While the satisfaction of patients with hip joint TEP is 95%, it is only 80-85% in patients with knee TEP, according to Windhagen. "A knee prosthesis does not make every patient a happy person," said the AE-President.
It is not uncommon to complain about restricted mobility and pain, which has to do with the complex anatomy of this joint. "The knee joint is guided much more by soft parts than the hip joint," explained Windhagen, and the forms of movement are more complex. A knee is not a pure hinge joint, it rolls, slides and turns outward and inward. The femur and tibial bone remain in contact with the movement of the knee. Therefore, the implantation of an artificial knee is particularly demanding.
All conservative therapies should be exhausted
A nationally or internationally accepted consensus on the exact indication or the optimal time for a knee replacement is not yet. According to Windhagen, the minimum requirements for a knee TEP include structural damage with advanced cartilage wear (usually caused by arthrosis) as well as knee pain, which significantly impairs the quality of life. All conservative therapies should be exhausted.
At least half a year, younger patients over one year, should be tried, the painkillers and physical training to get the symptoms under control before surgery. Patients should also be aware that the procedure is a one-way street, revisions may be needed and the old condition can not be restored, Windhagen said.
The procedures differ considerably from country to country and also regionally in Germany. In some centers implantation is very rapid, but in other centers restrained. The preoperative state of the patients before the implantation of a knee endoprosthesis also varies.
Frequent expectations, especially of younger patients, to have unlimited sports options after the procedure are unrealistic and should be eliminated. "An artificial joint is not a fountain of youth," said Professor Dr. med. med. Karl-Dieter Heller, Chief Physician of the Orthopedic Clinic at the Duchess Elisabeth Hospital in Braunschweig. Should be discouraged the patient from more extreme sports loads such as football or boxing. "The more intensive the load, the greater the risk of premature loosening of the implants," emphasized Heller. Moderate physical stress such as skiing, running, swimming, golfing, cycling or hiking, however, are readily available for patients with joint endoprosthesis.
Orthopedic Clinic Markgroeningen
The Center for Endoprosthetics, Foot Surgery and Rheumatoid Orthopedics of the Orthopedic Clinic Markgroeningen has 80 inpatient beds and performs about 2,500 surgeries per year. The focus of the center is in arthroplasty, where about 800 hip endoprostheses, 870 knee endoprostheses, 60 shoulder endoprostheses and 20 ankle prostheses are implanted per year.
The artificial joints are implanted using state-of-the-art, minimally invasive, tissue-conserving surgical techniques that select small accesses and protect the soft tissues as best as possible. Here, the center has established itself as an international reference center.
Osteoarthritis, i. Morbid wear on the articular cartilage is the most common cause of knee pain and is becoming increasingly important in joint damage, even at a younger age. If the cartilage in the knee joint wears off, this is a process that can not be undone. Hyaline cartilage, which protects the bone at the condyle, is unable to heal itself if damaged. The increased wear of the cartilage leads to direct bone-to-bone contact. The consequences of osteoarthritis on the knee ("gonarthrosis") are severe pain during exercise. The painless walking distances are getting shorter. Finally, even in dormancy severe pain. At the same time, the mobility and stability of the knee joint are getting worse. The cause is often a malposition of the legs. For example, X or O legs strain the knee joints one-sidedly. But even accidents or the sports injuries mentioned above are the cause of the wear.
Double sled / joint replacement: The bicondylar knee replacement (resurfacing) is for patients whose knee joint is variously damaged. In the case of completely destroyed knees, it is also possible to implant surface knee endoprostheses with mobile parts ("mobile bearing") in younger and active patients in order to imitate the most "physiological" movement possible.
In the replacement of the knee prosthesis, it is necessary to secure a new prosthesis again safely in the bone and to obtain a stable, well-movable knee joint. In this case, usually modular revision prostheses with different degrees of coupling and different components for bone fixation or for bone defect reconstruction must be selected or combined individually depending on the bone and soft tissue situation.
Case study - Knee replacement
In a 64-year-old female patient, an external O-leg of an external knee total endoprosthesis implantation resulted in a malposition in the thigh. During preoperative diagnosis, a simultaneous periprosthetic infection is detected. In a first operation, the old prosthesis is first removed and an antibiotic-releasing placeholder is used. Furthermore, systemic antibiotics are given to treat the infection. After 14 days, the patient is first mobilized home on two forearm crutches. Four weeks later, a new axle-guided prosthesis is implanted and the thigh axis is simultaneously corrected by a changeover. Due to the earlier infection, six weeks are again given antibiotics. The patient can be mobilized quickly under full load and leaves the clinic again after 14 days.