Histopathologische Diagnostik in der Endoprothetik

The durability of endoprosthetic implants of the large joints has increased over the last decades. North American studies have shown a 10-year durability of 94% for prosthetic hip implants, and European studies have shown 10-year durabilities of 88–95%. Pathologists differentiate three etiological disease patterns for the“pathology of endoprosthetics” that lead to reduction of implant durability: 1) periprosthetic particle disease (aseptic loosening), 2) infection, and 3) arthrofibrosis. Four types of neosynovitis/periprosthetic membrane have been determined in a consensus classification: particle-induced type (type I), with a mean prosthesis durability (MPD) of 12 years; infectious type (type II), MPD 2.5 years; combined type (type III), MPD 4.2 years; and indeterminate type (type IV), MPD 5.5 years. There are three histopathologic degrees of arthrofibrosis; grade 1 always needs clinical information for diagnosis, whereas grades 2 and 3 are distinct histopathologic entities.     

CD3+ lymphocytosis in the peri-implant membrane of 222 loosened joint endoprostheses depends on the tribological pairing

Background and purpose — The most frequent cause of arthroplasty failure is aseptic loosening—often induced by particles. Abrasion material triggers inflammatory reactions with lymphocytic infiltration and the formation of synovial-like interface membranes (SLIM) in the bone–implant interface. We analyzed CD3 quantities in SLIM depending on articulating materials and possible influences of proven material allergies on CD3 quantities.

Patients and methods — 222 SLIM probes were obtained from revision surgeries of loosened hip and knee arthroplasties. SLIM cases were categorized according to the SLIM-consensus classification and to the particle algorithm. The CD3 quantities were analyzed immunohistochemically, quantified, and correlated to the particle types.

Results — Metal–metal pairings showed the highest CD3 quantities (mean 1,367 counted cells). CD3 quantities of metal–polyethylene (mean 243), ceramic–polyethylene (mean 182), and ceramic–ceramic pairings (mean 124) were significantly smaller. Patients with contact allergy to implant materials had high but not statistically significantly higher CD3 quantities than patients without allergies. For objective assessment of the CD3 response as result of a pronounced inflammatory reaction with high lymphocytosis (adverse reaction), a defined CD3 quantity per high power field was established, the “CD3 focus score” (447 cells/0.3?mm², sensitivity 0.92; specificity 0.90; positive predictive value 0.71; negative predictive value 0.98).

Interpretation — The high CD3 quantities for metal–metal pairings may be interpreted as substrate for previously described adverse reactions that cause severe peri-implant tissue destruction and SLIM formation. It remains unclear whether the low CD3 quantities with only slight differences in the various non-metal–metal pairings and documented contact allergies to implant materials have a direct pathogenetic relevance.     

Akromion- und Spina-scapulae-Frakturen nach Implantation einer inversen Schultertotalendoprothese

The use of the reverse shoulder prosthesis for therapy of several pathologies of the shoulder became more and more reliable over the past few years. Resulting from the increasing number of implantations, the therapy and prophylaxis of implant related complications become important as well. The fracture of the acromion and the scapular spine is a prevalent complication and appears in 2–15?% of the cases. Currently, there is no standardized therapy at hand and the results are often unsatisfying. With the intention of a shorter period of rehabilitation and better functional results, we performed an open reduction and internal fixation in 6 patients with dislocated type 2 or type 3 fractures in the years 2010/2011. One year after the performed operation, a definite decrease of pain but a persistent deficiency in strength and range of motion can be seen. Nevertheless 5 of 6 the 6 treated patients were satisfied with the result. Regarding the present data revision surgery, especially conversion operations have a conspicuous higher fracture rate. Particularly in those cases an accurate soft tissue balancing with an extensive release is an important factor to avoid overload of the acromion and scapular spine. Whether modern, non-elongating designs of convertible prosthesis will lead to a decrease of the fracture rate remains to be seen.     

The cause of loosening in cemented hip joint prostheses. Light and electron microscopy study and laser microprobe mass analysis

Aseptic loosening of joint prostheses is a quantitatively increasing problem. For evaluation of the pathogenesis of prosthesis loosening joint capsules and tissue membranes taken from the femoral and acetabular bone-cement-interface of 23 hips revised for aseptic loosening were examined. In all cases we found an excessive inflammatory histiocytic reaction with intracytoplasmatic incorporation of a small granular foreign material. This could be identified to be zirconium oxide by LAMMA-analysis. Zirconium oxide and polymethylmethacrylate (PMMA) wear particles could be shown in the cytoplasm of histiocytes by transmission electron microscopy. By quantitative grading of the histiocytic reaction and the intracellular granular wear particles we found that both were evenly distributed around the loosened prosthesis. Chronic inflammation due to bone cement abrasion is regarded as a leading cause of aseptic prosthesis loosening.     

Titanium particles up-regulate the activity of matrix metalloproteinase-2 in human synovial cells

Purpose

Wear debris particle-induced osteolysis and subsequent aseptic loosening is one of the major causes of failure of total joint replacement. The purpose of this study was to investigate the effect of titanium implant material and inflammatory cytokines on human synovial cells and the development to osteolysis and aseptic loosening.

Methods

This study investigated the effect of titanium implant material on the ECM-degraded MMP-2 in human synovial cells and analyzed the contribution of synovial cells in osteolysis and aseptic loosening.

Results

When human synovial cells are exposed to titanium materials, MMP-2 activity is induced by 1.72 ± 0.14-fold with Ti disc and 3.95 ± 0.10-fold with Ti particles, compared with that of the controls, respectively. Inflammatory cytokines TNFα and IL-1β are also shown to induce MMP-2 activity by 3.65 ± 0.28-fold and 6.76 ± 0.28-fold, respectively. A combination of Ti particles and cytokines induces MMP-2 activities to a higher level (10.54 ± 0.45-fold). Inhibitors of various signal pathways involved in MMP-2 reverse Ti particle-induced MMP-2 activities.

Conclusions

Synovial cells surrounding the bone–prosthesis interface may contribute to production of MMP-2, and NFκB inhibitors may be explored as potential therapeutics to alleviate wear debris-induced osteolysis and aseptic loosening.     

Histopathologische Diagnose der periprothetischen Gelenkinfektion nach Hüftgelenkersatz

Background

The distinction between aseptic and septic loosening of a total hip arthroplasty is a diagnostic challenge. Therapy and clinical success depend on the correct diagnosis. Histopathological evaluation of the periprosthetic interface membrane is one possible diagnostic parameter; detailed analysis of tissue characteristics may reflect the cause of failure. This study evaluated the diagnostic value of a published histopathological consensus classification for the periprosthetic interface membrane in the identification of periprosthetic joint infection (PJI).

Methods

Between 2004 and 2008, a prospective analysis was performed in 106 patients who had revisions because of assumed PJI. Based on clinical presentation, radiography, and haematological screening, infection was assumed, and a joint aspiration was performed. Based on these findings, a two-stage revision was performed, with intraoperative samples for culture and histological evaluation obtained. Final diagnosis of infection was based on the interpretation of the clinical presentation and the preoperative and intraoperative findings. The basis for histopathological evaluation was the consensus classification for the periprosthetic interface membrane. Sensitivity, specificity, and accuracy were calculated for each parameter.

Results

In 92 patients, a positive diagnosis of PJI could be made. Histopathology yielded the highest accuracy (0.93) in identification of PJI, identifying 86 of 92 infections (69 type II, 17 type III). In 13 of the 14 noninfected hips, histopathology correlated in 13 (93%) cases (10 type I, three type IV). The accuracies of microbiological culture, C-reactive protein, and aspiration were 0.82, 0.86, and 0.54, respectively.

Conclusion

In the diagnosis of PJI, histopathological evaluation of the periprosthetic interface membrane proved very effective. To analyse the cause of prosthesis loosening, tissue samples of the periprosthetic interface membrane should be evaluated on the basis of the consensus classification in all revision surgeries.     

Male gender,Charnley class C,and severity of bone defects predict the risk for aseptic loosening in the cup of ABG I hip arthroplasty

Background  

We studied which factor could predict aseptic loosening in ABG I hip prosthesis with hydroxyapatite coating. Aseptic loosening and periprosthetic osteolysis are believed to be caused, at least in part, by increased polyethylene (PE) wear rate via particle disease. Based on it, increased PE wear rate should be associated with aseptic loosening regardless of the type of implant.     

Migration pattern of a femoral short-stem prosthesis: a 2-year EBRA-FCA-study

Introduction

Short-stem prostheses enable bone stock preserving total hip arthroplasty. However, little is known about the durability of this group of implants. The most common cause for implant failure is aseptic loosening. Early implant migration is supposed to be the best indicator for mechanical failure of femoral stems. The purpose of this study was to evaluate the migration pattern of a short stem implant and the influence of BMI, gender and femoral offset on implant migration.

Materials and methods

After a minimum follow-up of 2 years, 72 hips were included in this EBRA-FCA-study. The mean age at surgery of the 34 female and 32 male patients was 54 years (range 22–75 years). The mean BMI was 29 kg/m² (range 21–51 kg/m²).

Results

Mean axial subsidence was 1 mm (±1.4 mm) after 24 months. BMI, gender and implant offset did not influence implant migration on a statistical significant level. Nevertheless, a tendency towards more migration in obese and female patients was observed.

Conclusion

The evaluated short stem prosthesis showed a migration pattern similar to clinical proven standard straight stem implants. The indication of short-stem prostheses should be critically evaluated in obese and female patients.     

Increased interleukin-8 (IL-8) expression is related to aseptic loosening of total hip replacement

Aseptic loosening is an increasing problem in total hip replacement (THR). Chronic inflammatory reaction against implant wear particle results in collageno- and osteolysis, leading to loosening of the implant. Cytokines are known to play a major role in this particular inflammatory process [10]. The aim of the present study was to examine interleukin-8 (IL-8) in the synovial-like interface membrane (SLIM) and pseudocapsular tissue of THRs and to compare it to normal knee synovial membrane. Eleven patients suffering from aseptically loosened THRs were included. All the SLIM and pseudocapsular tissue samples were obtained during revision operations. Ten control samples of normal synovium were collected per arthroscopy from the superior recessus of the knee. For immunohistochemical IL-8 detection, polyclonal mouse anti-human immunoglobulin (Ig)G₁ IL-8-primary antibody was used with the alkaline phosphatase anti-alkaline phosphatase (APAAP) method. Results were quantitated using the Vidas image analysis system. The highest count levels (mean ± SEM) were detected in SLIM tissue (386 ± 82 cells/mm²). The difference was statistically significant compared with pseudocapsular tissue (193 ± 36 cells/mm²) and control samples (18 ± 5 cells/mm²). Count levels in control tissue were on average 5% of the SLIM tissues values. The present study determines for the first time the cellular origin of IL-8 in aseptically loosened THRs and also quantitates the IL-8-producing cells in the periprosthetic tissue. The results reveal a high rise in IL-8 concentration in SLIM and in synovial tissues. This finding moves us one step forward in solving the complex network of multiple factors affecting loosening of hip implants. Received: 10 November 1998     

Endovaskuläre Behandlung des Aortenbogenaneurysmas

There are a variety of treatment options for complex aortic arch pathologies. The key to success in aortic arch surgery includes an understanding of the pathology, reasonable indications including correct decisions on treatment options and an uneventful procedure. In modern aortic arch surgery it is not the available treatment option but the pathology which should define the best form of treatment. One of the aortic arch treatment options is implantation of the double-branched Relay aortic arch stent graft prosthesis including a carotid-subclavian bypass on the left side. This device consists of the main body and two stent grafts dedicated to supra-aortic vessels. The main body includes two internal tunnels as proximal landing zones for the supra-aortic stent grafts. During the main body implantation the brain perfusion remains uninterrupted. The first results after double-branched stent graft implantation are promising. In the first published series with 15 patients, the perioperative mortality and stroke incidence were 7%. There was no endoleak type Ia or type III; however, the number of patients is low and the long-term results are not available at present.     

Diagnostik und Therapie der Luxation nach Hüfttotalprothesenimplantation

Background

Luxation following endoprosthetic hip replacement represents a frequent and severe complication and is the reason for a relevant number of hip arthroplasty revision interventions. The probability of occurrence of luxation of a total hip arthroplasty is associated with the indications, patient and operation-specific risk factors. Approximately 50 % of luxations after total hip arthroplasty occur within 3 months of the operation (early luxation).

Diagnostics

The diagnostics of luxation of total hip arthroplasty are carried out by clinical and radiological methods. The causative assignment is made by assessment of joint stability, the bony situation (e.g. loosening, periprosthetic fracture and defects) and the soft tissue (e.g. pelvitrochanterian musculature). In cases of clinical and paraclinical signs of infection and of late luxations, a joint puncture is indicated.

Therapy

Therapy decisions are made depending on the cause (e.g. implant malpositioning, pelvitrochanterian insufficiency, impingement, incongruence between head and inlay and combinations of causes). Therapy of acute total hip prosthesis luxation begins with imaging controlled repositioning carried out with the patient under adequate analgesia and sedation. Conservative therapy is carried out by immobilization with a hip joint orthesis or pelvis-leg cast for 6 weeks. Operative therapy strategies for recurrent luxation are restoration of the correct implant position and sufficient soft tissue tension. Larger hip heads, bipolar heads and tripolar cups are more commonly used due to the geometrically lower probability of dislocation (higher jumping distance). Luxation of total hip prostheses due to infection is treated according to the principles of periprosthetic infection therapy. The rate of recurrence of luxation of 30 % is high so that in cases of unsuccessful therapy treatment should best be carried out in a center for revision arthroplasty.

Conclusions

The search for the exact cause of total hip prosthesis luxation is extremely important. A classification is only possible when the exact cause is known and together with patient and implant-specific details the therapeutic approach can be ascertained. In revision operations the intraoperative functional diagnostics must be exactly documented. The reasons for delayed luxations could be prosthesis infections, abrasion and loosening.     

Ellenbogenendoprothetik

Total elbow arthroplasty (TEA) is a reliable choice in treating inflammatory and posttraumatic osteoarthritis as well as complex fractures of the elbow, especially in non-reconstructable distal humeral fractures of the elderly. Newer prosthesis designs use a semi-constrained mechanism that has in-built sloppy hinges (varus/valgus mobility ±7°). Triceps-on approaches should be preferred whenever possible to avoid postoperative triceps insufficiency. Current 10-year survival rates of 90% have been reported. A TEA leads to reduction of pain levels and to a satisfactory range of motion. The most common complications are infections, aseptic loosening, joint instability and implant failure. Radial head replacement is commonly used for treatment of non-reconstructable radial head fractures but can also be performed in case of posttraumatic osteoarthritis. A monopolar, long stem, non-cemented prosthesis is preferred in the acute situation at our institution. The Kocher approach allows good exposure of the lateral elbow and can thereby help to avoid overstuffing. Recent studies have shown good to excellent clinical outcomes in 70–90% of cases. The most common complications are overstuffing, infections, implant failure and posttraumatic osteoarthritis.     

Synovial Metallosis After Ceramic Total Ankle Arthroplasty Treated With a Total Talar Prosthesis: A Case Report

Total ankle arthroplasty is a useful surgical procedure for osteoarthritis of the ankle, but aseptic loosening of components is an issue. We report here a case of aseptic implant loosening with metallosis after total ankle arthroplasty using the TNK ankle (Kyocera, Kyoto, Japan), which occurred despite the components being ceramic. We also report favorable results from our method of treatment using a total talar prosthesis in the revision surgery. During the revision surgery, synovial metallosis was found, probably related to superficial damage to the screw affixing the tibial component to the bone. Because both the tibial and talar components were loose, all the components and the remaining talar bone were removed. A new tibial component and a custom-made alumina-ceramic total talar prosthesis was inserted. Pain relief was achieved and maintained through the latest follow-up visit at 42 months after revision surgery. Dorsiflexion of the ankle improved from 0° to 5° and plantarflexion remained unchanged from its preoperative range of 20°. The American Orthopaedic Foot & Ankle Society ankle-hindfoot score improved from 38 to 80 points. To the best of our knowledge, this is the first reported case of an alumina-ceramic total ankle prosthesis loosening caused by metallosis resulting from screw abrasion. Favorable treatment results were obtained by using a total talar prosthesis in the revision surgery.     

Implantation eines Femurteilersatzes nach periprothetischer Femurfraktur

The development of modular prostheses is becoming increasingly important in revision surgery due to the rising need of arthroplasty in knee and hip joints. The demand for suitable prostheses is high because of the desire for a higher mobility and a good postoperative functionality, whereby preliminary experience with megaprostheses using modular implant systems in orthopedic oncology have already been obtained. Considering the clinical outcome of our 58-year-old patient (obesity III, BMI 58) and the third revision operation after two periprosthetic fractures, a megaprosthesis was implanted (Mega C-system, co. Link, Hamburg). We aimed both at good clinical functionality and good stability of the knee joint. After the implant, a good functional result was observed at the beginning; however, there were some indices for prosthesis loosening. During the fourth revision we implanted a total femoral replacement. Postoperatively, a good clinical outcome after intensive physiotherapy was observed. Nevertheless, the use of megaprostheses has to be judged cautiously because of a lack of long-term results. In addition, it should not be used as a standard implant in periprosthetic joint surgery because of the risk of aseptic loosening during its course.     

Implantatassoziierte Infektion – Diagnostik

The diagnosis of implant-associated infections is challenging as chronic low-grade infections often only manifest as subtle clinical symptoms. Clinical evaluation, patient history, imaging, histopathological and microbiological examinations build the cornerstones of the diagnostics for implant-associated infections. New onset of pain at rest, local symptoms at the surgical site and early loosening of the prosthesis or pseudarthrosis should raise suspicion for an infection and prompt further evaluation. Percutaneous sinus tracts, purulent wound secretions and skin erosions with exposure of the implant are certain signs of implant-associated infections. Elevated C?reactive protein levels in blood support the diagnosis of infection but are neither sufficient sensitive nor specific to confirm or exclude infection. Preoperative antibiotic therapy interferes with the diagnostic evaluation and should be avoided. In periprosthetic joint infections, joint aspiration with determination of the leukocyte count and microbiological examination is a crucial first diagnostic step. Through microbiological and histopathological examinations of intraoperative tissue samples, as well as sonication of explanted implants, the causative pathogen can be identified in most cases. In osteosynthesis-associated infections imaging plays a key role to detect non-union, infection callus, sequester, peri-implant osteolysis and extraosseous and intramedullary pathologies. In prosthetic joint infections imaging provides information about the position and stability of the prosthesis. In case of hematogenic infection seeding from a distant focus, blood cultures should be sampled, followed by a meticulous investigation of potential primary focus of infection, depending on the causative agent.     

Does the cement mantle thickness influence the glenoid loosening in anatomic total shoulder arthroplasty? An experimental study

Background

Glenoid component loosening is the most frequent failure mode. Few data are available on the effect of thickness of cement on glenoid loosening. The purpose of this study is to determine if the cement mantle thickness influences the mode and localization of loosening. Our hypotheses are: 1) failure is caused by traction stresses generated within the cement mantle and 2) a thicker cement mantle amplifies the rocking horse effect.

人工全髋聚乙烯假体磨损及其生物学效应

目的 探讨人工关节聚乙烯磨损与假体松动的关系。方法 采用光镜与电镜对15例人工髋关节翻修病例的聚乙烯假体臼杯内表面及假体周围软组织作形态学观察。进而在动物实验中观察微小聚乙烯磨损颗粒促使骨吸收性细胞因子增加，植入物周围骨溶解以及植入物-骨整合强度下降的生物效应。结果 聚乙烯假体在人工关节松动形成时均明显磨损，聚乙烯磨损颗粒诱发机体单核-巨噬细胞增殖并分泌骨吸收性细胞因子。结论 聚乙烯磨损与假体松动密度相关。其中生物因素是引起假体松动的主要途径。     

Eine neuartige Kniegelenksendoprothese mit physiologischer Gelenkform

The human medial tibial plateau is concave, whereas the lateral tibial plateau is convex. In a normal knee, the convex femoral condyles roll and glide on the tibia during the standing phase of walking. The designs of most commercially available knee prostheses do not take this morphological feature into consideration. The novel design of the AEQUOS G1 knee replacement prosthesis is based on the natural anatomy of the knee joint, with a convex lateral tibia plateau and a sagittal offset of the medial and lateral compartments. Following extensive development and testing, initial clinical results of the AEQUOS G1 prosthesis in a mulitcenter study are presented. From Mai 2005 to March 2007, 158 patients in 4 clinics underwent total knee arthroplasty with the AEQUOS G1 and agreed to participate in the study. Patients were evaluated preoperatively and at 3, 6 and 12 months of follow-up using a standardized protocol that included the American Knee Society Score (AKSS), the Oxford Knee Score (OKS) and the Visual Analog Scale (VAS) for pain. After 3 months, 151 patients appeared for follow up appointments, after 6 months, 134, and after 12 months, 127. The mean range of motion preoperatively was 97.0° (±19.9°) and 107.5° (±15.9°) 12 months after surgery. The AKSS, as well as the modified OKS, significantly improved (p<0.0001) from preoperative scores of 98.8 (±35.8) and 37.3 (±6.9) points, respectively, to 165.8 (±34.1) and 21.9 (±7.8) points, preoperatively, and 12 months postoperatively. The VAS score significantly decreased (p<0.001) from 7.4 (±1.8) points preoperatively to 1.9 (±2.2) points 12 months postoperatively. One implant was revised because of arthrofibrosis and another due to patellar luxation. Two patients required revision because their implants revealed malalignement with ligamentous instability. No infections, aseptic loosening or other implant-specific complications were observed at this early follow-up. Good clinical results were observed at early follow-up with the AEQUOS G1 knee arthroplasty. However, longer follow-up is necessary for a general evaluation of the implant.     

Allergic reactions in arthroplasty: myth or serious problem?

Purpose

The purpose of this study was to determine the prevalence of sensitisation to chromium, cobalt, nickel, or a cement component in patients who received endoprosthetic surgery at our institution. Also, we aimed to assess the portion related to allergic reactions in endoprosthetic revisions and to follow-up those patients after allergic reaction related revisions.

Methods

We selected patients with a pre-operative known sensitisation to chromium, cobalt, nickel, or a cement component for a post-operative allergic reaction. All patients who received revision surgery because of a potential allergic reaction were followed up post revision surgery.

Results

Eight hundred fifty-five patients were pre-operative known to have a sensitisation to chromium, cobalt, nickel, or a cement component. Six hundred eighty-two patients (79.8 %) received a primary arthroplasty, and 173 patients (20.2 %) received a revision surgery. Seventeen patients (2.0 %) were revised because of allergic reactions. Allergic reactions were the cause for approximately 0.2 % of all endoprosthetic revisions and for 9.8 % of revisions in patients with sensitisation to one of the reviewed components. Potential allergens were strictly avoided in the replaced prosthesis. Outcome scores improved post-operatively.

Conclusions

The allergic patient should be thoroughly informed about potential reactions resulting from implant choice. Our study can serve as risk assessments by quantifying the incidence of allergic reactions due to endoprosthetic treatment.

     

Mid-term to long-term followup of two-stage reimplantation for infected total knee arthroplasty

Between January 1989 and December 1994, 94 patients (96 knees) had a two-stage reimplantation for treatment of an infected total knee arthroplasty. All patients were treated with an interval antibiotic-loaded static cement spacer and had antibiotic-loaded bone cement for prosthesis fixation at the time of reimplantation. The purpose of this study was to assess the long-term risk of reinfection and the mechanical durability of these reimplantation arthroplasties. Patients were followed up for a median of 7.2 years (range, 2.5-13.2 years). At final followup, 15 knees (16%) had required reoperation. Nine knees (9%) had component removal for reinfection and six knees (6%) were revised for aseptic loosening. The median time to reoperation for reinfection was 1 year (range, 0.1-9.8 years). The risk of recurrent infection was not correlated with the type of organism, patient demographics, or method of prosthesis fixation at reimplantation. The survivorship free of implant removal for any reason was 90% (confidence intervals, 83.9-96.4%) at 5 years and 77.3% (confidence intervals, 65.5-89.6%) at 10 years. The survivorship free of implant removal for reinfection was 93.5% (confidence intervals, 88.5-98.7%) at 5 years and 85% (confidence intervals, 73.8-96.3%) at 10 years. Survival free of revision for mechanical failure (aseptic loosening or radiographic loosening) was 96.2% (confidence intervals, 92-100%) at 5 years and 91% (confidence intervals, 80.8-98.3%) at 10 years. These results suggest that the high likelihood of early success after two-stage reimplantation of an infected TKA is well maintained throughout long-term followup, with a modest rate of late recurrent infection or mechanical implant failure.