Aims

Despite numerous studies focusing on periprosthetic joint infections (PJIs), there are no robust data on the risk factors and timing of metachronous infections. Metachronous PJIs are PJIs that can arise in the same or other artificial joints after a period of time, in patients who have previously had PJI.

Aims

Despite numerous studies on periprosthetic joint infections (PJI), there are no robust data on the risk factors and timing of metachronous infections. This study was performed to answer the following questions: 1) Is there any difference of manifestation time of metachronous PJIs between different localizations of multiple artificial joints? 2) Can we identify any specific risk factor for metachronous PJIs for different localizations of multiple artificial joints?

Aim

The prevalence of unexpected positive cultures (UPC) in aseptic revision surgery of the joint with a prior septic revision procedure in the same joint remain unknown. The purpose of this study was to determine the prevalence of UPC in aseptic revisions performed in patients with a previous septic revision in the same joint. As secondary outcome measure, we explore possible risk factors associated with UPC and the re-revision rates.

Aims

The outcome of repeat septic revision after a failed one-stage exchange for periprosthetic joint infection (PJI) in total knee arthroplasty (TKA) remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat septic revision after a failed one-stage exchange, and to determine whether the Musculoskeletal Infection Society (MSIS) stage is associated with subsequent infection-related failure.

Aims

One-stage exchange for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) is gaining popularity. The outcome for a repeat one-stage revision THA after a failed one-stage exchange for infection remains unknown. The aim of this study was to report the infection-free and all-cause revision-free survival of repeat one-stage exchange, and to investigate the association between the Musculoskeletal Infection Society (MSIS) staging system and further infection-related failure.

Aims

One-stage revision hip arthroplasty for periprosthetic joint infection (PJI) has several advantages; however, resection of the proximal femur might be necessary to achieve higher success rates. We investigated the risk factors for resection and re-revisions, and assessed complications and subsequent re-revisions.

Arthrofibrosis is a relatively frequent complication after total knee arthroplasty. Although stiffness after total hip arthroplasty (THA), because of formation of heterotopic ossification or other causes, is not uncommon, to the authors’ best knowledge, arthrofibrosis after THA has not been described. The aim of this study is to describe the arthrofibrosis of the hip after primary total hip arthroplasty using an established clinical and histological classification of arthrofibrosis.

We retrospectively examined all patients who were histologically confirmed to have arthrofibrosis after primary THA during revision surgery by examination of tissue samples in our clinic. Arthrofibrosis was diagnosed according to the histopathological SLIM-consensus classification, which defines seven different SLIM types of the periimplant synovial membrane. The SLIM type V determines the diagnosis of endoprosthesis-associated arthrofibrosis.

The study population consists of 66 patients who were revised due to arthrofibrosis after primary THA. All patients had a limitation in range of motion prior to revision with a mean flexion of 90° (range from 40 to 125), mean internal rotation of 10° (range from 0 to 40) and mean external rotation of 20° (range from 0 to 50). All patients had histological SLIM type V arthrofibrosis, corresponding to endoprosthesis-associated arthrofibrosis. Histological examination revealed that seven patients (10.6%) had particle-induced and 59 patients (89.4%) had non-particle-induced arthrofibrosis.

This is the first decription of endoprosthetic-associated arthrofibrosis after primary THA on the basis of a well-established histological classification. Our study results could enable new therapeutic and diagnostic opportunities in patients with such an arthrofibrosis. Surgeons should keep arthrofibrosis as a possible cause for stiffness and pain after primary total hip arthroplasty in mind. Level of evidence Diagnostic study, Level of Evidence IV

Thorsten Gehrke and Lara Althaus contributed equally to the writing of this manuscript.

Ceramic bearings are currently the most widely used alternative to metal-on-polyethylene bearings in total hip arthroplasty (THA). A workgroup at International Consensus Meeting (ICM) analyzed the potential link between the type of bearing surface and the subsequent periprosthetic joint infection (PJI), and found a higher incidence of PJI when using a metal-on-metal (MoM) bearing surface. A potential reason is that the failure of a MoM bearing surface can result in adverse local tissue reactions (ALTR), which might provide a favorable environment for bacterial proliferation.

In the last few years, several observational studies including national registries, showed that metal-on-polyethylene (MoP) bearing surfaces are associated with a higher rate of infection following total hip arthroplasty (THA) compared to ceramic bearings, in particular with the use of ceramic-on-ceramic bearing (CoC) surfaces.

After adjusting for selection bias and various confounding factors, patients treated with ceramic bearings experienced reduced risk of infection and MoP bearing surface is an independent risk factor correlating with higher incidence of PJI. The meta-analysis by Lee et al. comparing MoM with CoC cementless THA confirmed that the MoM is associated with a significantly higher revision rate than CoC group for any reason as well as for PJI. Furthermore, initial in-vitro studies have shown lower bacterial biofilm formation on ceramic bearing surfaces. Summarizing the current literature, ceramic bearings are associated with a lower risk of infection following THA.

Revision total hip arthroplasty (THA) is a challenging procedure and the removal of well-fixed femoral stems can be compounded by several pitfalls. In such cases, several removal techniques have been presented in the literature. The most commonly used techniques are the transfemoral osteotomy presented by Wagner and the extended trochanteric osteotomy (ETO) described by Younger et al. Both techniques allow the surgeon to have better intraoperative exposure of the fixation surfaces of the solid femoral stems. However, the complication rates such as non-union should not be underestimated. Therefore, it is always a good decision to avoid an ETO if alternative techniques exist. The endofemoral surgical technique is an alternative method for the removal of well-fixed cemented and cementless femoral stems. Tips and tricks of the endofemoral technique for the removal of well-fixed femoral stems are presented.

Total hip arthroplasty has become one of the most successful orthopaedic procedures with long-term survival rate. An ever-increasing acceptance of the potential longevity of THA systems has contributed to an increasing incidence of THA in younger and more active patients. Nowadays, especially in younger patients, cementless THA is the favored method worldwide.

Since the first cementless THA in late 1970s, many implant designs and modifications have been made. Despite excellent long-term results for traditional straight cementless stems, periprosthetic fractures or gluteal insufficiency are still a concern. For instance, as reported in a meta-analysis by Masonis and Bourne, the incidence of gluteal insufficiency after THA varies between 4% and 22%.

In contrast, the flattened lateral profile of the SP-CL^® anatomical cementless stem can protect the greater trochanter during the use of cancellous bone compressors and can avoid gluteal insufficiency after THA. Another benefit of this stem design is the rotational stability and the natural load transfer due to the anatomical concept. In this context, we report our experiences using the SP-CL^® anatomical cementless stem. The study group consists of 1452 THA cases (850 male, 602 female) with an average age of 62 years (range 25–76 years). After a mean follow-up of 20 months, in seven cases (0.5%) a stem exchange was necessitated. The reason for stem revision was periprosthetic fracture in 4 cases (0.3%) and periprosthetic joint infection in three cases (0.2%). In five patients, hip dislocation and in four patients migration of the stem occurred. However, stem exchange was not required in those cases.

In conclusion, the SP-CL^® anatomical cementless stem has excellent short-term results.

Introduction

Despite several preventive strategies, periprosthetic joint infection (PJI) following total joint arthroplasty (TJA) is still a devastating complication. Early diagnosis and appropriate treatment are crucial to achieve successful infection control, but challenging since there is no test with 100% sensitivity and 100%. Therefore, several national and international guidelines include synovial analysis of joint aspirates as important diagnostic criteria, but cut-off levels for synovial cell count (CC) and polymorphonuclear (granulocyte) percentage (PMN%) are still debatable. The current investigation was performed to analyze the overall accuracy and optimal cut-off of synovial CC and PMN% following total knee (TKA) and total hip arthroplasty (THA).

Femoral revision after cemented total hip arthroplasty (THA) might include technical difficulties, following essential cement removal, which might lead to further loss of bone and consequently inadequate fixation of the subsequent revision stem. Bone loss may occur because of implant loosening or polyethylene wear, and should be addressed at time of revision surgery. Stem revision can be performed with modular cementless reconstruction stems involving the diaphysis for fixation, or alternatively with restoration of the bone stock of the proximal femur with the use of allografts.

Impaction bone grafting (IBG) has been widely used in revision surgery for the acetabulum, and subsequently for the femur in Paprosky defects Type 1 or 2. In combination with a regular length cemented stem, impaction grafting allows for restoration of femoral bone stock through incorporation and remodeling of the proximal femur. Cavitary bone defects affecting the metaphysis and partly the diaphysis leading to a wide femoral canal are ideal indications for this technique. In case of combined segmental-cavitary defects a metal mesh is used to contain the defect which is then filled and impacted with bone grafts. Cancellous allograft bone chips of 2 to 4 mm size are used, and tapered into the canal with rods of increasing diameters. To impact the bone chips into the femoral canal a dummy of the dimensions of the definitive cemented stem is inserted and tapped into the femur to ensure that the chips are firmly impacted. Finally, a standard stem is implanted into the newly created medullary canal using bone cement. To date several studies from Europe have shown favorable results with this technique, with some excellent long-term results reported.

Advantages of IBG include the restoration of the bone stock in the proximal femur, the use of standard length cemented stems and preserving the diaphysis for re-revision. As disadvantages of the technique: longer surgical time, increased blood loss and the necessity of a bone bank can be mentioned.

The treatment of extensive bone loss and massive acetabular defects is a challenging procedure, especially in cases with concomitant pelvic discontinuity (PD). Pelvic discontinuity describes the separation of the ilium proximally from the ischio-pubic region distally. The appropriate treatment strategy is to restore a stable continuity between the ischium and the ilium to reconstruct the anatomical hip center. Several treatment options such as antiprotrusio cages, metal augments, reconstruction cages with screw fixation, structural allograft with plating, jumbo cups, oblong cups and custom-made triflange acetabular components have been described as possible treatment options. Cage and/or ring constructs or acetabular allograft are commonly used techniques with unsatisfactory results and high failure rates. More favorable results have been presented with custom triflange acetabular components (CTAC), although the results are still unsatisfactory. Three-dimensional printing technology (3DP) has already become part of the surgical practice. In this context, preliminary clinical and radiological results using a 3D-printed custom acetabular component in the management of extensive acetabular defects are presented. The overall complication rate was 33.3 %. In one out of 15 patients (6.6 %), implant-associated complication occurred revealing an overall implant-associated survival rate of 93.3%. The 3D-printed custom acetabular component suggests a promising future, although the manufacturing process has high costs and the complication rate is still high.

Periprosthetic joint infection (PJI) is one of the most feared complications following total knee arthroplasty (TKA). Despite improved peri-operative antibiotic management and local antibiotic-loaded bone cement PJI is reported in about 0.5–1.9 % of primary knee replacement. In case of revision knee arthroplasty the infection rate even occurs at about 8–10 %. Depending on an acute or late PJI several surgical methods are used to treat the infection. However, suffering of a late PJI, the only surgical procedure remains the exchange of the TKA in combination with a radical debridement and removal of all foreign material.

In order to achieve complete debridement of the joint, the soft tissue must be radically excised. Frequently, the debridement of the posterior capsule causes severe difficulties, therefore it might be necessary to resect the collateral ligaments to be able to reach the posterior parts of the capsule. But this necessitates the use of a higher level of constraint such as a rotating or total hinge and fully cemented long stemmed revision implants. Furthermore, due to the cemented stems, a sufficient amount of antibiotic-loaded cement may be delivered to the bone as topical therapy.

Up to now, several studies have shown excellent functional long-term results for hinge knee prostheses after PJI and a very good infection control rate.

Advantages of the hinge knee prosthesis in cases of PJI are the opportunity for a complete debridement especially while addressing the posterior capsule after resection of the collateral ligaments and for delivering antibiotic-loaded bone cement at the stems of the prosthesis for topic therapy. Disadvantages are the need for a higher level of constraint and a possible higher blood loss due to the radical debridement.

Total joint arthroplasty (TJA) is one of the most successful procedures in orthopaedics. Despite the excellent clinical and functional results, periprosthetic joint infection (PJI) following TJA is a feared complication. For instance, the reported PJI rate after primary total knee arthroplasty is about 0.5–1.9%. In general, prevention of periprosthetic joint and surgical site infections is of utmost importance.

This can be reduced by strict antisepsis, adequate sterilization of the surgical instruments and meticulous surgical technique. An indisputable role in prevention of SSI in TJA has been the use of peri-operative systemic antibiotic prophylaxis. The most common recommended antibiotics for prophylaxis in TJA are cefazolin or cefuroxime. In contrast, routine use of commercial antibiotic-loaded bone cement (ALBC) in primary total joint arthroplasty is still a concern of open debate. The use of antibiotic-loaded bone cement delivers a high concentration of antibiotics locally and can decrease the infection rate, which is supported by several studies in the literature. In this context, we present the pros of routine use of commercial antibiotic-loaded bone cement.

The presence of obesity has negative influence on the progress of osteoarthritis and increases the risk of undergoing a primary THA at an earlier age. However, the correlation of BMI and the risk for postoperative complications, revision surgery and infection rate is still controversial. In the largest cohort to this date, we used the German insurance claims database to evaluate the correlation of BMI and the risk of postoperative complications, mortality and revision rates following primary THA.

Using nationwide billing data of the German health-care insurance for inpatient hospital treatment, we identified patients over the age of 20 years who had undergone either THA or short-stem THA between January 2012 and December 2014. BMI was classified into four groups (< 30 kg/m², 30 to 34.9 kg/m², 35 to 39.9 kg/m², > 40 kg/m²). In all patients, the 90-day complication, mortality and revision rates were calculated. Furthermore, all complications and revisions were determined at a latest follow-up of 1 year. We used multivariable logistic regression to model the odds of complications as a function of BMI groups. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated.

A total of 131,576 total hip arthroplasties in 124,368 patients were included for final analysis. BMI had a significant effect on risk adjusted 1-year overall complications, 1-year revision surgery and 90-day surgical complications. The adjusted odd ratios increased significantly with BMI category. Especially morbidly obese patients with a BMI >40 kg/m² had a threefold higher risk for deep infection and a two-fold higher risk for the overall complication and revision rates as compared to patients with a BMI <30 kg/m².

Obesity plays an important role in patients undergoing primary THA, especially patients with a BMI beyond 40 kg/m² have a markedly higher risk for revision surgery and overall complication rates. This study aims to increase awareness among physicians in order to improve risk stratifications and to better educate patients with regard to obesity and postoperative expectations prior to undergoing elective total hip arthroplasty.

Aim

Alpha-defensin was recently introduced as a new biomarker having a very high accuracy to rule out periprosthetic joint infection (PJI). A new rapid lateral flow version of the Alpha-defensin test was developed and introduced to detect high levels of Alpha-defensin in synovial fluid quickly and with ease. We conducted a single-centre prospective clinical study to compare the results of the Alpha-defensin rapid test* against the conventional diagnostics according to MSIS criteria.

The treatment of extensive bone loss and massive acetabular defects is a challenging procedure, especially the concomitant pelvic discontinuity (PD) can be compounded by several challenges and pitfalls. The appropriate treatment strategy is to restore a stable continuity between the ischium and the ilium and to reconstruct the anatomical hip center. Antiprotrusio cages, metal augments, reconstruction cages with screw fixation, structural allograft with plating, jumbo cups, oblong cups and custom-made triflange acetabular components have been reported as possible treatment options. Nevertheless, the survivorship following acetabular revision with extensive bone loss is still unsatisfactory. The innovation of three-dimensional printing (3DP) has become already revolutionary in engineering and product design. Nowadays, the technology is becoming part of surgical practice and suitable for the production of precise and bespoke implants. The technique of a 3D-printed custom acetabular component in the management of extensive acetabular defect is presented.

Revision total hip arthroplasty (THA) is a challenging procedure, especially in cases with well-fixed implants. In such cases, several removal techniques have been presented in the current literature, while the most commonly used techniques are the transfemoral osteotomy or the extended trochanteric osteotomy (ETO). Those techniques allow the surgeon to have a better intra-operative exposure of the fixation surfaces of the solid femoral stems. However, the complication rates such as non-union are not unremarkable. Therefore, it is always a good decision to avoid an ETO if alternative techniques exist. The endofemoral surgical technique is an alternative method for the removal of well-fixed cemented and uncemented femoral stems.

The method of choice in the management of chronic infections is the exchange arthroplasty. The exchange arthroplasty can be performed either in a one- or in a two-stage setting, whereas the two-stage exchange arthroplasty is still considered the “gold standard” worldwide. The current literature and guidelines for PJI treatment deliver no clear evidence that a two-stage exchange procedure has a clearly higher success rate than the one-stage procedure. Since the first implantation of mixing antibiotics into bone cement in 1970s, the ENDO-Klinik followed until today in over 85% of all infected cases the one-stage exchange arthroplasty for the management of PJI. The main requirement is the known germ with known susceptibility based on microbiological diagnostics. Proper bone stock for cemented, in some cases, uncemented reconstruction, and the possibility of primary wound closure are also clear assumptions. The one-stage exchange arthroplasty delivers diverse advantages. For instance, the need for only one operation, shorter hospitalization, reduced systemic antibiotics and lower overall cost. A well-defined pre-operative planning regime is absolutely mandatory.

Despite the prophylactic use of antibiotics and hygienic strategies, surgical site infection following total joint arthroplasty (TJA) is still a severe and unsolved complication. Since antibiotic-loaded bone cement (ALBC) was introduced by Buchholz in the 1970s, the use of ALBC has been increasingly used for the prevention and treatment of periprosthetic infection (PPI). However, the routine use of ALBC during primary TJA remains controversial. Recent clinical studies have found that ALBC is effective in reducing the risk of PJI following primary TJA. Although ALBC having the advantage of reducing the risk of PJI, the main disadvantages are the possible development of toxicity, antibiotic resistance, allergic reaction, and possible reduction of the mechanical properties of bone cement. Nevertheless, a recent published article demonstrated, that the use of high dose dual-antibiotic impregnated cement reduce significantly the rate of surgical site infections compared to standard low dose single ALBC in the setting of a hip fracture treating with hemiarthroplasty. Furthermore, Sanz-Ruiz et al. presented that the use of ALBC in TJA has favorable cost-efficiency profile. In this context, reasons why surgeons should use antibiotic-loaded bone cement during primary TJA are demonstrated.

The World Health Organization (WHO) and the Centre for Disease Control and Prevention (CDC) recently published guidelines for the prevention of surgical site infection. The WHO guidelines, if implemented worldwide, could have an immense impact on our practices and those of the CDC have implications for healthcare policy in the United States.

Our aim was to review the strategies for prevention of periprosthetic joint infection in light of these and other recent guidelines.

Cite this article: Bone Joint J 2017;99-B(4 Supple B):3–10.

Objectives

Mechanical wear and corrosion at the head-stem junction of total hip arthroplasties (THAs) (trunnionosis) have been implicated in their early revision, most commonly in metal-on-metal (MOM) hips. We can isolate the role of the head-stem junction as the predominant source of metal release by investigating non-MOM hips; this can help to identify clinically significant volumes of material loss and corrosion from these surfaces.

Femoral revision in cemented THA might include some technical difficulties, based on loss of bone stock and cement removal, which might lead to further loss of bone stock, inadequate fixation, cortical perforation or consequent fractures. Femoral impaction grafting, in combination with a primary cemented stem, allows for femoral bone restoration due to incorporation and remodeling of the allograft bone by the host skeleton. Historically, it has been first performed and described in Exeter in 1987, utilizing a cemented tapered polished stem in combination with morselised fresh frozen bone grafts. The technique was refined by the development of designated instruments, which have been implemented by the Nijmegen group from Holland.

Indications might include all femoral revisions with bone stock loss, while the ENDO-Klinik experience is mainly based on revision of cemented stems. Cavitary bone defects affecting meta- and diaphysis leading to a wide or so called “drain pipe” femora, are optimal indications for this technique, especially in young patients. Contraindications are mainly: septical revisions, extensive circumferential cortical bone loss and noncompliance of the patient.

Generally the technique creates a new endosteal surface to host the cemented stem by reconstruction of the cavitary defects with impacted morselised bone graft. This achieves primary stability and restoration of the bone stock. It has been shown, that fresh frozen allograft shows superior mechanical stability than freeze-dried allografts. Incorporation of these grafts has been described in 89%.

Technical steps include: removal of failed stem and all cement, reconstruction of segmental bone defects with metal mesh (if necessary), preparation of fresh frozen femoral head allografts with bone mill, optimal bone chip diameter 2 – 5 mm, larger chips for the calcar area (6 – 8 mm), insertion of an intramedullary plug including central wire, 2 cm distal to the stem tip, introduction of bone chips from proximal to distal, impaction started by distal impactors over central wire, then progressively larger impactors proximal, insertion of a stem “dummy” as proximal impactor and space filler, removal of central wire, retrograde insertion of low viscosity cement (0.5 Gentamycin) with small nozzle syringe, including pressurization, insertion of standard cemented stem. The cement mantle is of importance, as it acts as the distributor of force between the stem and bone graft and seals the stem. A cement mantle of at least 2 mm has shown favorable results. Originally the technique is described with a polished stem. We use standard brushed stems with comparable results. Postoperative care includes usually touch down weight bearing for 6–8 weeks, followed by 4–6 weeks of gradually increased weightbearing with a total of 12 weeks on crutches.

Survivorship with a defined endpoint as any femoral revision after 10 year follow up has been reported by the Exeter group being over 90%. While survivorship for revision related to aseptic loosening being above 98%. Within the last years various other authors and institutions reported similar excellent survivorships, above 90%. In addition a long term follow up by the Swedish arthroplasty registry in more than 1180 patients reported a cumulative survival rate of 94% after 15 years.

Impaction grafting might technically be more challenging and more time consuming than cement free distal fixation techniques. It, however, enables a reliable restoration of bone stock which might become important in further revision scenarios in younger patients.

Periprosthetic fractures involving the femoral meta/diaphysis can be treated in various fashions. The overall incidence of those fractures after primary total knee arthroplasties (TKA) ranges from 0.3 to 2.5%, however, can increase above 30% in revision TKA, especially in older patients with poorer bone quality. Various classifications suggest treatment algorithms. However, they are not followed consequently. Revision arthroplasty becomes always necessary if the implant becomes loose. Next, it should be considered in case of an unhappy TKA prior to the fracture rather than going for an osteosynthesis. Coverage of the associated segmental bone loss in combination with proximal fixation, can be achieved in either cemented or non-cemented techniques, with or without the combination of osteosynthetic fracture stabilization. Severe destruction of the metaphyseal bone, often does not allow adequate implant fixation for the revision implant and often does not allow proper anatomic alignment. In addition the destruction might include loss of integrity of the collaterals. Consequently standard or even revision implants might not be appropriate. Although first reports about partial distal femoral replacement are available since the 1960´s, larger case series or technical reports are rare within the literature and limited to some specialised centers. Most series are reported by oncologic centers, with necessary larger osseous resections of the distal femur.

The implantation of any mega prosthesis system requires meticulous planning, especially to calculate the appropriate leg length of the implant and resulting leg length. After implant and maybe cement removal, non-structural bone might be resected. Trial insertion is important due to the variation of overall muscle tension and recreation of the former joint line. So far very few companies offer yet such a complete, modular system which might also be expanded to a total femur solution. Furthermore it should allow the implantation of either a cemented or uncemented diaphyseal fixation. In general, the fracture should be well bridged with a longer stem in place. At least 3 cm to 5 cm of intact diaphysis away to the fracture site is required for stable fixation for both cemented and cementless stems. Application of allograft struts and cables maximises the biomechanical integrity of the fracture zone to promote fracture repair and implant fixation. Modular bridging systems do allow centimeter wise adaption distally, to the knee joint. Consequently in modern systems fully hinged or rotational hinge knee systems can be coupled, and adjusted accordingly to the patellar tracking and joint line. Fixation of the tibial component can be achieved in uncemented and cemented techniques. We still prefer the latter.

Although a reliable and relatively quick technique, frequent complications for all mega systems have been described. These usually include infections, rotational alignment and loosening of the femoral fixation or subsequent proximal femoral fractures. Infections usually can be related to large soft tissue compromise or extensive exposure or longer procedure times. Thus implantation of such reconstruction systems should be reserved to specialised centers, with adequate facilities experience, in order to minimise complications rates and optimise patients function postoperative.

The two-staged exchange for periprosthetic joint infection (PJI) has become the “gold standard” worldwide. Based on the first implementation of mixing antibiotics into bone cement by Prof. Buchholz in the 1970s, the ENDO-Klinik followed a distinct one staged exchange for PJI in over 85 % of all our infected cases until today. Looking carefully at current literature and guidelines for the PJI treatment, there is no clear evidence, that a two-staged procedure has a clearly higher success rate than a one-staged approach. Although postulated in relevant articles, most recommendations, e.g. duration of antibiotics, static vs. mobile spacer, interval of spacer retention, cemented vs. uncemented implant fixation, are based on Level IV to III evidence studies or expert opinions, rather than on prospective randomised or comparative data.

Potentially a cemented one-stage exchange offers certain advantages, as mainly based on need for only one operative procedure, reduced antibiotics & hospitalization time and reduced relative overall costs. In order to fulfill a one-staged approach with the above described potential success, there are obligatory pre-, peri- and postoperative details, which need to be meticulously respected. The absolute mandatory infrastructural requirement is based on the clear evidence of the bacteria in combination with a distinct patient specific plan, by an experienced microbiologist, for following topical antibiotics in the bone cement with combined systemic antibiotics.

Mandatory preoperative diagnostic testing is based on the joint aspiration with an exact identification of the bacteria. The presence of a positive bacterial culture and respective antibiogramm is essential, to specify the antibiotics loaded into the bone cement, which allows a high topical antibiotic elution directly at the surgical site. A specific treatment plan is generated by a microbiologist. Contraindications for a one-staged exchange include: failure of >2 previous one-staged procedures, infection spreading to the nerve-vessel bundle, unclear preoperative bacteria specification, unavailability of appropriate antibiotics, high antibiotic resistance.

The surgical success relies not only on the complete removal of all preexisting hardware material (including cement and restrictors), furthermore an aggressive and complete debridement of any infected soft tissues and bone material is needed. Mixing antibiotics into the cement needs to fulfill the following criteria: Appropriate antibiogramm, adequate elution characteristics, bactericidal (exception clindamycin), powder form (never use liquid AB), maximum addition of 10 %/PMMA powder. Current principles of modern cementing techniques should be applied.

Postoperative systemic antibiotic administration is usually followed for only 10–14 days (exception: streptococci). We recommend an early and aggressive mobilization within the first 8 days postoperatively, due to the cemented fixation an immediate mobilization under full weight bearing becomes possible in most cases.

Persistence or recurrence of infection remains the most relevant complication in the one-staged technique. As failure rates with a two-staged exchange have been described between 9% and 20% in non-resistant bacteria, the ENDO-Klinik data shows comparative results after 8–10 years of follow up.

In summary a cemented one-stage exchange offers various advantages. Mainly the need for only one operation, shorter hospitalization, reduced systemic antibiotics, lower overall cost and relative high patient satisfaction. However, a well-defined preoperative planning regime including an experienced microbiologist is absolutely mandatory.

Aim

A key of success in the treatment of prosthetic joint infection (PJI) is the proper diagnosis. There is a lack of diagnostic tools able to diagnose a PJI with high accuracy. Alpha-defensin has been proposed as possible solution but the available literature is still limited. This prospective study was carried out in order to determine (1) what is the sensitivity, the specificity, the positive and the negative predictive value of the Alpha-defensin immunoassay test in diagnosing PJI; (2) which clinical features may be responsible for false positive and false negative results?

Implant, surgeon, and patient-related factors all contribute to the risk of revision requiring an ETO. It is shown in the literature that the ETO can be a successful and easy-to-be-performed technique, but it can also lead to a bunch of complications, like peri-prosthetic fracture, loosening of the implant, damage of the isthmus and especially nonunion of the greater trochanter, which could result in an insufficiency limping with positive Trendelenburg Sign.

We do not believe in the necessity of an extended trochanteric osteotomy, which is extremely rarely performed at our institution. In almost all cases, the stem can be removed using an endofemoral approach from the top. Special instruments are necessary, and retrograde slap hammers are helpful. In general, cortical windows may be required to gain access to the bone-implant interface, but only in cases of well-fixed cementless components or if the distal cement is difficult to reach and remove. A full range of narrow and wide osteotomes of various thicknesses should be available. Those are our most important tools. Multiple osteotomes, which are carefully driven between the interfaces from all sides, can be gradually wedged or forced out of their cement mantle, even if stemmed. Generally, cemented and cementless procedures could be considered for reconstruction. We recommend performing the procedure only when the surgeon is proficient. This papers tries to provide such strategies.

Femoral revision in cemented THA might include some technical difficulties, based on loss of bone stock and cement removal, which might lead to further loss of bone stock, inadequate fixation, cortical perforation or consequent fractures. Cemented THA has become an extremely successful operation with excellent long-term results. Although showing decreasing popularity in North America, it always remained a popular choice for the elderly patients in Europe and other parts of the world. Various older and recent studies presented excellent long-term results, for cemented fixation of the cup as well as the stem. Besides optimal component orientation, a proper cementing technique is of major importance to assure longevity of implant fixation. Consequently a meticulous bone bed preparation assures the mechanical interlock between the implant component, cement and the final bone bed. Pre-operative steps as proper implant sizing/ templating, ensuring an adequate cement mantle thickness, and hypotensive anaesthesia, minimizing bleeding at the bone cement interface, are of major importance. Additionally, femoral impaction grafting, in combination with a primary cemented stem, allows for femoral bone restoration due to incorporation and remodeling of the allograft bone by the host skeleton. Historically, it has been first performed and described in Exeter in 1987, utilizing a cemented tapered polished stem in combination with morselised fresh frozen bone grafts. The technique was refined by the development of designated instruments, which have been implemented by the Nijmegen group from Holland. Indications might include all femoral revisions with bone stock loss, while the Endo-Clinic experience is mainly based on revision of cemented stems. Cavitary bone defects affecting meta- and diaphysis leading to a wide or so called “drain pipe” femora, are optimal indications for this technique, especially in young patients. Contraindications are mainly: septical revisions, extensive circumferential cortical bone loss and noncompliance of the patient.

The cement mantle is of importance, as it acts as the distributor of force between the stem and bone graft and seals the stem. A cement mantle of at least 2 mm has shown favorable results. Originally the technique is described with a polished stem. We use standard brushed stems with comparable results. Relevant complications include mainly femoral fractures due to the hardly impacted allograft bone. Subsidence of tapered polished implants might be related to cold flow within the cement mantle, however, could also be related to micro cement mantle fractures, leading to early failure. Subsidence should be less than 5 mm.

Impaction grafting might technically be more challenging and more time consuming than cement-free distal fixation techniques. It, however, enables a reliable restoration of bone stock which might especially become important in further revision scenarios in younger patients.

Revision of total hip arthroplasty (THA) is being performed with increasing frequency. However, outcomes of repeated revisions have been rarely reported in the literature, especially for severe defects. Cup revision can be a highly complex operation depending on the bone defect. In acetabular defects like Paprosky types 1 and 2 porous cementless cups fixed with screws give good results. Modern trabecular metal designs improve these good results. Allografts are useful for filling cavitary defects. In acetabular defects Paprosky types 3A and 3B, especially the use of trabecular metal cups, wedges, buttresses and cup-cage systems can produce good results. Difficult cases in combination with pelvic discontinuity require reconstruction of the acetabulum with acetabular plates or large cup-cages to solve these difficult problems. However, there is still no consensus regarding the best option for reconstructing hips with bone loss. Although the introduction of ultraporous metals has significantly increased the surgeon's ability to reconstruct severely compromised hips, there remain some that cannot be managed readily using cups, augments, or cages. In such situations custom acetabular components may be required. Individual implants represent yet another tool for the reconstructive surgeon. These devices can be helpful in situations of catastrophic bone loss. Ensuring long-term outcome, mechanical stability has a greater impact than restoring an ideal center of rotation. However, despite our consecutive case series there are no mid- to long-term results available so far. Re-revision for failed revision THA acetabular components is a technically very challenging condition.

Background

Cement restrictors are used for maintaining good filling and pressurization of bone cement during hip and knee arthroplasties. The limitations of certain cement restrictors include the inability to accommodate for large medullary canals particularly in revision procedures. We describe a technique using SurgicelTM (Johnson & Johnson) and SPONGOSTAN™ (Johnson & Johnson) (Fig 1) to form a cement restrictor that can accommodate for large canal diameters and provide excellent pressurisation.

Generally cemented total hip arthroplasty (THA) has become an extremely successful operation with excellent long-term results. Although it always remained a popular choice for the elderly patients in many countries, recent trends show an increased use of noncemented stems in all age populations in many national registries. So far, there has been no clear age associated recommendation, when a cemented stem should be used. Described major complications including periprosthetic fractures are usually associated with age >75 years, in many registries. Uncemented stems perform better than cemented stems in recent registries; however, unrecognised intra-operative femoral fractures may be an important reason for early failure of uncemented stems. Experimental studies have indicated that intra-operative fractures do affect implant survival, it has been shown that intra-operative and direct post-operative fractures increase the relative risk of revision during the first 6 post-operative months significantly. In addition it has been clearly shown, that uncemented stems were more frequently revised due to periprosthetic fracture during the first 2 post-operative years than cemented stems.

Based on the overall femoral bone quality, especially in female patients >70 years, cemented fixation has a lower fracture risk. Based on the implant fixation type: metaphyseal vs. diaphyseal of various uncemented stems, major attention should be drawn to the intra-operative bone quality during the broaching process, especially for metaphyseal fixation stem types. Although cementless distal fixation can be achieved in thick cortices still in many patients, the incidence of associated thigh pain needs to be considered for some implant types. Furthermore small femoral canals might generate certain implant-bone size mismatch in relation to the proximal femur.

In any cemented THA, a proper cementing technique is of major importance to assure longevity of implant fixation. This also includes proper implant sizing/templating, ensuring an adequate cement mantle thickness, which might be restricted in a small diameter femur. The desired outcome is a cement interdigitation into cancellous bone for 2–3 mm and an additional mantle of 2 mm pure cement. Consequently proper planning in small diameter patients, prevents sizing problems, while in few cases special/individualised stem sizes might be considered.

The two-staged exchange for periprosthetic joint infection (PJI) has become the “gold standard” worldwide. Based on the first implementation of mixing antibiotics into bone cement by Prof. Buchholz in the 70's, the ENDO-Klinik followed a distinct one-staged exchange for PJI in over 85% of all our infected cases until today. Looking carefully at current literature and guidelines for the PJI treatment, there is no clear evidence, that a two-staged procedure has a clearly higher success rate than a one-staged approach. Although postulated in relevant articles, most recommendations, e.g. duration of antibiotics, static vs. mobile spacer, interval of spacer retention, cemented vs. uncemented implant fixation, are based on level IV to III evidence studies or expert opinions, rather than on prospective randomised or comparative data.

Potentially a cemented one-stage exchange offers certain advantages, as mainly based on need for only one operative procedure, reduced antibiotics & hospitalization time and reduced relative overall costs. In order to fulfill a one-staged approach with the above described potential success, there are obligatory pre-, peri- and post-operative details, which need to be meticulously respected. The absolute mandatory infrastructural requirement is based on the clear evidence of the bacteria in combination with a distinct patient specific plan, by an experienced microbiologist, for the topical antibiotics in the bone cement with combined systemic antibiotics.

Mandatory pre-operative diagnostic testing is based on the joint aspiration with an exact identification of the bacteria. The presence of a positive bacterial culture and respective antibiogramm is essential, to specify the antibiotics loaded to the bone cement, which allows a high topical antibiotic elution directly at the surgical site. A specific treatment plan is generated by a microbiologist. Contraindications for a one-staged exchange include: failure of > 2 previous one-staged procedures, infection spreading to the nerve-vessel bundle, unclear pre-operative bacteria specification, unavailability of appropriate antibiotics, high antibiotic resistance.

The surgical success relies not only on the complete removal of all preexisting hardware material (including cement and restrictors), furthermore an aggressive and complete debridement of any infected soft tissues and bone material is needed. Mixing antibiotics to the cement needs to fulfill the following criteria: Appropriate antibiogramm, adequate elusion characteristics, bactericidal (exception clindamycin), powder form (never use liquid AB), maximum addition of 10%/PMMA powder. Current principles of modern cementing techniques should be applied.

Post-operative systemic antibiotic administration is usually followed for only 10–14 days (exception: streptococci). We recommend an early and aggressive mobilization within the first 8 days post-operatively due to the cemented fixation an immediate mobilization under full weight bearing becomes possible in most cases.

Persistence or recurrence of infection remains the most relevant complication in the one-staged technique. As failures rates with a two-staged exchange have been described between 9% and 20% in non-resistant bacteria, the ENDO-Klinik data shows comparative results after 8–10 years of follow up, which were confirmed independently also by some other international reports and study groups.

In summary a cemented one-stage exchange offers various advantages. Mainly the need for only one operation, shorter hospitalization, reduced systemic antibiotics, lower overall cost and relatively high patient satisfaction. However a well-defined pre-operative planning regime including an experienced microbiologist is absolutely mandatory.

In primary TKA, non- or semi-constrained TKA implants might have their limitations in the absence of collateral ligaments, severe deformity, large osseous defects and gross flexion-extension instability.

Although most primary TKA indications can be solved with modular, non-hinged implants, an adequate balancing might require a relevant soft tissue release. This consequently adds complexity and operative time with less predictable results in the elderly patient. The current literature reporting on short- to mid-term results of rotating hinged implants in primary osteoarthritis shows some quite diverse results and consequently different interpretations of this implant type in primary knee arthroplasty. Although some authors were able to show good and excellent clinical results in 91% of patients and consequent survival rates of a rotating hinge implant after 15 years up to 96% in primary indications, others found high complication rates of up to 25% of all operated patients, which remains unclear for us and is inconsistent with our clinical results in primary and revision TKA in over 30 years of experience with the ENDO-Model rotating hinge implant.

Our potential indications in the elderly for a rotating or pure hinged implant in primary TKA include: Complete MCL instability; Severe varus or valgus deformity (>20 degrees) with necessary relevant soft tissue release; Relevant bone loss including insertions of collaterals; Gross flexion-extension gap imbalance; Ankylosis; One staged implantation with specific antibiotics after PJI.

Due to general limited soft tissues or hyperlaxity, patients with neuropathic joints, or lack of extensor mechanism should be considered for a complete hinged implant. The ENDO-model hinge has only been minimally adapted since its development in the 70´s, including fully cemented long stems, in modular and non-modular versions. We strictly reserve a rotational hinge in primary indications for patients >70 years with a combined varus alignment, whereas in severe valgus deformities, a complete hinged implant version should be used for our implant design.

Periprosthetic joint infection (PJI) is one of the most feared and challenging complications following total knee arthroplasty. We provide a detailed description of our current understanding regarding the management of PJI of the knee, including diagnostic aids, pre-operative planning, surgical treatment, and outcome.

Cite this article: Bone Joint J 2015;97-B(10 Suppl A):20–9.

Knee arthrodesis is a potential salvage procedure for limb preservation after failure of total knee arthroplasty (TKA) due to infection. In this study, we evaluated the outcome of single-stage knee arthrodesis using an intramedullary cemented coupled nail without bone-on-bone fusion after failed and infected TKA with extensor mechanism deficiency. Between 2002 and 2012, 27 patients (ten female, 17 male; mean age 68.8 years; 52 to 87) were treated with septic single-stage exchange. Mean follow-up duration was 67.1months (24 to 143, n = 27) (minimum follow-up 24 months) and for patients with a minimum follow-up of five years 104.9 (65 to 143,; n = 13). A subjective patient evaluation (Short Form (SF)-36) was obtained, in addition to the Visual Analogue Scale (VAS). The mean VAS score was 1.44 (SD 1.48). At final follow-up, four patients had recurrent infections after arthrodesis (14.8%). Of these, three patients were treated with a one-stage arthrodesis nail exchange; one of the three patients had an aseptic loosening with a third single-stage exchange, and one patient underwent knee amputation for uncontrolled sepsis at 108 months. All patients, including the amputee, indicated that they would choose arthrodesis again. Data indicate that a single-stage knee arthrodesis offers an acceptable salvage procedure after failed and infected TKA.

Cite this article: Bone Joint J 2015;97-B:649–53.

Cemented total hip arthroplasty (THA) has become an extremely successful operation with excellent long-term results. Although it always remained a popular choice for the elderly patients in many countries, recent trends show an increased use of non-cemented stems in all age populations in many national registries. So far, there has been no clear age associated recommendation, when a cemented stem should be used. Described major complications such as periprosthetic fractures are usually associated at age >75 years, in many registries. Uncemented stems perform better than cemented stems in recent registries; however, unrecognised intraoperative femoral fractures may be an important reason for early failure of uncemented stems. Experimental studies have indicated that intraoperative fractures do affect implant survival, in addition it has been shown that intraoperative and direct postoperative fractures increase the relative risk of revision during the first 6 postoperative months significantly. Furthermore it has been clearly shown, that uncemented stems were more frequently revised due to periprosthetic fracture during the first 2 postoperative years than cemented stems.

Although often associated reduction of femoral bone quality in especially female patients >60 years, uncemented fixation has become the standard in most scenarios worldwide. Based on the implant fixation type: metaphyseal vs. diaphyseal of various uncemented stems, major attention should be, however, drawn to the intraoperative bone quality during the broaching process, especially for metaphyseal fixation stem types. Although cementless distal fixation can be achieved in thick cortices still in many patients, the incidence of associated thigh pain needs to be considered for some implant types. Furthermore small femoral canals might generate certain implant-bone size mismatch in relation to the proximal femur, thus nonoptimal fixation could be achieved. Consequently proper implant planning is mandatory preoperatively.

In any cemented THA, a proper cementing technique is of major importance to assure longevity of implant fixation. This also includes proper implant sizing/ templating, ensuring an adequate cement mantle thickness, which might be restricted in a small diameter femur. The desired outcome is a cement interdigitation into cancellous bone for 2–3mm and an additional mantle of 2mm pure cement. Consequently proper planning in small diameter patients, prevents sizing problems, while in few cases special/individualised stem sizes might be considered.

In summary attention needs to be drawn on small diameter stems, to prevent fractures and achieve proper implant fixation, in both uncemented and cemented fixation types. Proper implant planning preoperatively might be more important than in usual cases, while sometimes individual /small implant types might become necessary.

Cemented total hip arthroplasty (THA) has become an extremely successful operation with excellent long-term results. Although showing decreasing popularity in North America, it always remained a popular choice for the elderly patients in Europe and other parts of the world. Various older and recent studies presented excellent long-term results, for cemented fixation of the cup as well as the stem.

Besides optimal component orientation, a proper cementing technique is of major importance to assure longevity of implant fixation. Consequently a meticulous bone bed preparation assures the mechanical interlock between the implant component, cement and the final bone bed.

Preoperative steps as proper implant sizing/ templating, ensuring an adequate cement mantle thickness, and hypotensive anesthesia, minimising bleeding at the bone cement interface, are of major importance.

First the fossa pyriformis should be clearly identified, including the posterolateral entry point of the prosthesis. The femoral neck cut is usually 1.5cm to 2cm above the minor trochanter, based on the preoperative planning and implant type. Opening of the canal is done with an awl or osteotome, followed by any blunt tipped instrument, to follow the intramedullary direction. A box osteotome opens the lateral portion of the femoral neck, gently to preserve as much cancellous bone as possible. Sequential broaching follows carefully and according to the planning, to ensure preservation of 2mm to 3mm cancellous bone for interdigitation. Some systems might require over-broaching by one size. Trialing is done with the broach. Following, irrigation using a long nozzle pulsatile lavage, reduces the chance for fat embolism. A cement restrictor is then placed 1.5cm to 2cm distal to the tip of the stem, to ensure an adequate cement mantle distally. A second complete pulsatile irrigation of the canal follows, to minimise bleeding, followed by a dry sponge. Cement mixing is vacuum based in the meantime, usually 60–80g. We prefer the use of low dose antibiotic laden cement in our set up. Two to three minutes after mixing, the cement is applied rapidly in a retrograde technique, with a cement gun placing the nozzle tip against the cement restrictor. The gun is “pushed” out during the application, rather than being withdrawn from the canal. Proximal pressurization is first done by thumb, then with a proximal seal for 1 minute. The stem is inserted slowly using steady manual pressure, in the center of the cement mantle, however should never be impacted. The stem is aligned with the previously defined lateral entry point and is held in position until the cement hardens. The desired outcome is a cement interdigitation into cancellous bone for 2mm to 3mm and an additional mantle of 2mm pure cement.

The aim of this study was to assess the role of synovial C-reactive protein (CRP) in the diagnosis of chronic periprosthetic hip infection. We prospectively collected synovial fluid from 89 patients undergoing revision hip arthroplasty and measured synovial CRP, serum CRP, erythrocyte sedimentation rate (ESR), synovial white blood cell (WBC) count and synovial percentages of polymorphonuclear neutrophils (PMN). Patients were classified as septic or aseptic by means of clinical, microbiological, serum and synovial fluid findings. The high viscosity of the synovial fluid precluded the analyses in nine patients permitting the results in 80 patients to be studied. There was a significant difference in synovial CRP levels between the septic (n = 21) and the aseptic (n = 59) cohort. According to the receiver operating characteristic curve, a synovial CRP threshold of 2.5 mg/l had a sensitivity of 95.5% and specificity of 93.3%. The area under the curve was 0.96. Compared with serum CRP and ESR, synovial CRP showed a high diagnostic value. According to these preliminary results, synovial CRP may be a useful parameter in diagnosing chronic periprosthetic hip infection.

Cite this article: Bone Joint J 2015; 97-B:173–6.

The two-staged exchange for periprosthetic joint infection (PJI) has become the “gold standard” worldwide. Based on the first implementation of mixing antibiotics into bone cement by Prof. Buchholz in the 70's, the ENDO-Klinik followed a distinct one staged exchange for PJI in over 85% of all our infected cases until today. Looking carefully at current literature and guidelines for the PJI treatment, there is no clear evidence, that a two-staged procedure has a clearly higher success rate than a one-staged approach. Although postulated in relevant articles, most recommendations, e.g. duration of antibiotics, static vs. mobile spacer, interval of spacer retention, cemented vs. uncemented implant fixation, are based on level IV to III evidence studies or expert opinions, rather than on prospective randomised or comparative data.

Potentially a cemented one-stage exchange offers certain advantages, as mainly based on need for only one operative procedure, reduced antibiotics & hospitalization time and reduced relative overall costs. In order to fulfill a one-staged approach with the above described potential success, there are obligatory pre-, peri- and post-operative details, which need to be meticulously respected. The absolute mandatory infrastructural requirement is based on the clear evidence of the bacteria in combination with a distinct patient specific plan, by an experienced microbiologist, for following antibiotics in the bone cement with combined systemic antibiotics.

Mandatory preoperative diagnostic test is based on the joint aspiration with an exact identification of the bacteria. The presence of a positive bacterial culture and respective antibiogramm is essential, to specify the antibiotics loaded to the bone cement, which allows a high topic antibiotic elution directly at the surgical side. A specific treatment plan is generated by an microbiologist. Contraindications for a one staged exchange include: failure of >2 previous one-staged procedures, infection spreading to the nerve-vessel bundle, unclear preoperative bacteria specification, unavailability of appropriate antibiotics, high antibiotic resistance.

The surgical success relies not only on the complete removal of all preexisting hardware material (including cement and restrictors), furthermore an aggressive and complete debridement of any infected soft tissues and bone material is needed. Mixing antibiotics to the cement needs to fulfill the following criteria: Appropriate antibiogramm, adequate elution characteristics, bactericidal (exception clindamycin), powder form (never use liquid AB), maximum addition of 10%/PMMA powder. Current principles of modern cementing techniques should be applied.

Postoperative systemic antibiotic administration is usually followed for only 10–14 days (exception: streptococci). We recommend an early and aggressive mobilization within the first 8 days postoperatively, due to the cemented fixation an immediate mobilization under full weight bearing becomes possible in most cases.

Persistence or recurrence of infection remains the most relevant complication in the one-staged technique. As failures rates with a two-staged exchange have been described between 9% and 20% in non-resistant bacteria, the ENDO-Klinik data shows comparative results after 8–10 years of follow up, which were confirmed independently also by some other international reports and study groups.

In summary a cemented one-stage exchange offers various advantages. Mainly the need for only one operation, shorter hospitalization, reduced systemic antibiotics, lower overall cost and relative high patient satisfaction. However, a well-defined preoperative planning regime including an experienced microbiologist are absolutely mandatory.

Background:

Custom cutting guides (CCG) in total knee arthroplasty (TKA) use preoperative 3-dimensional imaging to fabricate cutting blocks specific to a patient's native anatomy. To date, small cohorts and short follow-up have limited reports studying clinical and functional outcomes of CCGs versus standard intramedullary and extramedullary alignment instrumentation. The purpose of this study was to determine if CCGs improve clinical outcomes versus standard alignment guides following TKA at a mean of 2 years postoperatively.

The use of hinged implants in primary total knee replacement (TKR) should be restricted to selected indications and mainly for elderly patients. Potential indications for a rotating hinge or pure hinge implant in primary TKR include: collateral ligament insufficiency, severe varus or valgus deformity (> 20°) with necessary relevant soft-tissue release, relevant bone loss including insertions of collateral ligaments, gross flexion-extension gap imbalance, ankylosis, or hyperlaxity. Although data reported in the literature are inconsistent, clinical results depend on implant design, proper technical use, and adequate indications. We present our experience with a specific implant type that we have used for over 30 years and which has given our elderly patients good mid-term results. Because revision of implants with long cemented stems can be very challenging, an effort should be made in the future to use shorter stems in modular versions of hinged implants.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):93–5.

Cemented total hip arthroplasty has become an extremely successful operation with excellent long term results. Although showing decreasing popularity in North America, it always remained a popular choice for the elderly patients in Europe and other parts of the world. Besides optimal component orientation, a proper cementing technique is of major importance to assure longevity of implant fixation. Consequently a meticulous bone bed preparation assures the mechanical interlock between the implant component, cement and the final bone bed.

Cementing the acetabular side should include preservation of the transverse acetabular ligament and clear identification of the medial wall. Medialisation and deepening of the socket are important at reaming, to ensure a containment of the cup. The contact of the cup to cancellous bone should be maximised. Either smaller reamers or 4–6mm anchoring holes can be drilled to the superior sclerosis. Smaller defects can be curettage, while larger ones might require cancellous bone grafting. Of major importance is the thoroughly pulsatile jet lavage with saline to irrigate the cancellous bone bed, to reduce fat and blood lamination. After final irrigation, before cementation, dry sponges are slightly impacted into the cavity, to dry it out. Cementation usually requires 40g of high viscosity bone cement. Immediate pressurisation of the cement into the bone bed should start after a general application time in our institution between 2.5 to 3 minutes after mixing; with either a sterile glove filled with a sponge or designated company specific pressuriser. Sustained pressurisation should be done for 1 minute. The original cup should be 3–4mm smaller than the last reamer, to ensure circumferential cement mantle. Insertion principle includes medialisation first, followed by gradual angulation of the cup. In appropriate position, a balled pressuriser maintains pressure without further moving of the implant, until cement hardening. Remnant cement can be removed with osteotomes, while remaining osteophytes should be flush with implant.

Femoral Side: First the fossa pyriformis should be clearly identified, including the posterolateral entry point of the prosthesis. The femoral neck cut is usually 1.5–2cm above the minor trochanter, based on the preoperative planning and implant type. Opening of the canal is done with an awl or osteotome, followed by any blunt tipped instrument, to follow the intramedullary direction. A box osteotome opens the lateral portion of the femoral neck, gently to preserve as much cancellous bone as possible. Sequential broaching follows carefully and according to the planning, to ensure preservation of 2–3mm cancellous bone for interdigitation. Some systems might require over-broaching by one size. Trialing is done with the broach. Following, irrigation using a long nozzle pulsatile lavage, reduces the chance for fat embolism. A cement restrictor is then placed 1.5–2cm distal to the tip of the stem, to ensure an adequate cement mantle distally. A second complete pulsatile irrigation of the canal follows, to minimise bleeding, followed by a dry sponge. Cement mixing is vacuum based in the meantime, usually 60–80g. We prefer the use of low dose antibiotic laden cement in our set up. Two to three minutes after mixing, the cement is applied rapidly in a retrograde technique with a cement gun, placing the nozzle tip against the cement restrictor. The gun is “pushed” out during the application, rather than being withdrawn from the canal. Proximal pressurisation is first done by thumb, then with a proximal seal for 1 minute. The stem is inserted slowly using steady manual pressure, in the center of the cement mantle, however, should never be impacted. The stem is aligned with the previously defined lateral entry point and is held in position until the cement hardens. The desired outcome is a cement interdigitation into cancellous bone for 2–3mm and an additional mantle of 2mm pure cement.

In primary TKA, non- or semi-constraint TKA implants might have their limitations in the absence of collateral ligaments, severe deformity, large osseous defects and gross flexion - extension instability. Although most primary TKA indications can be solved with modular, non-hinged implants, an adequate balancing might require a relevant soft tissue release. This consequently adds complexity and operative time with less predictable results in the elderly patient. The current literature reporting on short to mid-term results of rotating hinged implants in primary osteoarthritis shows some quite diverse results and consequently different interpretations of this implant type in primary knee arthroplasty. Although some authors were able to show good and excellent clinical results in 91% of patients and consequent survival rates of a rotating hinge implant after 15 years up to 96% in primary indications, others found high complication rates of up to 25% of all operated patients, which remains unclear for us and is inconsistent with our clinical results in primary and revision TKA in over 30 years of experience with the Endo-Model rotating hinge implant.

Our potential indications in the elderly for a rotating- or pure-hinged implant in primary TKA include: Complete MCL instability, Severe varus or valgus deformity (>20 degrees) with necessary relevant soft tissue release, Relevant bone loss including insertions of collaterals, Gross flexion-extension gap imbalance, Ankylosis, One staged implantation with specific antibiotics after PJI.

Due to general limited soft tissues or hyper laxity, patients with neuropathic joints, or lack of extensor mechanism should be considered to a complete hinged implant. The ENDO-model hinge has only been minimal adapted since its development in the 70's, including fully cemented long stems, in modular and non-modular versions. We strictly reserve a rotational hinge in primary indications for patients >70 years with a combined varus alignment, whereas in severe valgus deformities, a complete hinged implant version should be used for our implant design.

Massive proximal femoral bone loss can be a complex problem, despite various modern technical and implant solutions. Due to inadequate bone stock and missing proximal fixation possibilities, including larger segmental osseous defects, the use of a mega prosthesis might become necessary. Coverage of the segmental bone loss in combination with distal fixation, can be achieved in either cemented or non-cemented techniques. Some implant types allow for additional fixation of the gluteal muscles, attached with non-absorbable sutures or synthetic mesh grafts. Although first reports about partial or even complete femoral replacement are available since the 1960's, larger case series or technical reports are rare within the literature and limited to some specialised centers. Most series are reported by oncologic centers, with necessary larger osseous resections of the femur.

The final implantation of any mega prosthesis system requires meticulous planning, especially to calculate the appropriate leg length of the implant and resulting leg length. Combination of a posterior hip with a lateral knee approach allows for the enlargement to a total femur replacement, if necessary. The lateral vastus muscle is detached and the entire soft tissues envelope can be displaced medially. After implant and cement removal, non-structural bone might be resected. Trial insertion is important, due to the variation of overall muscle tension intraoperatively and prevention of early or late dislocation. Currently the use of proximal modular systems, including length, offset and anteversion adaption, became the technique of choice for these implant systems. However, just very few companies offer yet such a complete system, which might also be expanded to a total femur solution.

We were able to evaluate our Endo-Klinik results of total-femur replacements within 100 consecutive patients in non-infected cases, after a mean follow up time of five years. There we “only” 68% patients without complications, main complications included: 13% revealed a deep infection; dislocation was found in 6%, material failure and consequent breakage in 3%, persistent patellar problems in 2% and finally 1% with peroneal nerve palsy.

These results show that a total-femur replacement is associated with a high complication rate, even in non-infected patient cohorts.

The use of stems in revision TKA enhances implant stability and thus improves the survival rate. Stemmed components obtain initial mechanical stability when there is deficient metaphyseal bone. However the optimal method of stem fixation remains controversial, which includes selection of stem size, length or the use of cemented vs. cementless stems. Although postulated by many surgeons, there is no sufficient evidence, that cementless or hybrid fixation does perform better in the long term outcome, than cemented stems. In addition a number of studies, even from the U.S., suggested that there might be a benefit for the long term survival for cemented stems in revision TKA.

Obviously cemented stems have some few advantages in revision set up as: topic antibiotic delivery and initial strong fixation. While main disadvantages arise during limited/poor bone quality for initial cancellous bone-cement fixation; revision with removal of a long cement mantle and re-cementing into a previously cemented canal. Furthermore removing a fully cemented implant can be much more time consuming. The Endo Klinik has currently over 30 years of experience utilising cemented stems in combination with a rotating hinge implant in revision TKA, including satisfactory long-term results.

However we are aware of this technique associated limitations, including aseptic loosening and further conversion to a re-revision with necessary impaction bone grafting.

Generally it has to be mentioned, that type of stem and reconstruction type if often driven by surgeons own and institutional preference.

Fungal peri-prosthetic infections of the knee and hip are rare but likely to result in devastating complications. In this study we evaluated the results of their management using a single-stage exchange technique. Between 2001 and 2011, 14 patients (ten hips, four knees) were treated for a peri-prosthetic fungal infection. One patient was excluded because revision surgery was not possible owing to a large acetabular defect. One patient developed a further infection two months post-operatively and was excluded from the analysis. Two patients died of unrelated causes.

After a mean of seven years (3 to 11) a total of ten patients were available for follow-up. One patient, undergoing revision replacement of the hip, had a post-operative dislocation. Another patient, undergoing revision replacement of the knee, developed a wound infection and required revision 29 months post-operatively following a peri-prosthetic femoral fracture.

The mean Harris hip score increased to 74 points (63 to 84; p < 0.02) in those undergoing revision replacement of the hip, and the mean Hospital for Special Surgery knee score increased to 75 points (70 to 80; p < 0.01) in those undergoing revision replacement of the knee.

A single-stage revision following fungal peri-prosthetic infection is feasible, with an acceptable rate of a satisfactory outcome.

Cite this article: Bone Joint J 2014;96-B:492–6.

Louis Pasteur once said that: “Fortune favours the prepared mind.” As one of the great scientists who contributed to the fight against infection, he emphasised the importance of being prepared at all times to recognise infection and deal with it. Despite the many scientific discoveries and technological advances, such as the advent of antibiotics and the use of sterile techniques, infection continues to be a problem that haunts orthopaedic surgeons and inflicts suffering on patients.

The medical community has implemented many practices with the intention of preventing infection and treating it effectively when it occurs. Although high-level evidence may support some of these practices, many are based on little to no scientific foundation. Thus, around the world, there is great variation in practices for the prevention and management of periprosthetic joint infection.

This paper summaries the instigation, conduct and findings of a recent International Consensus Meeting on Surgical Site and Periprosthetic Joint Infection.

Cite this article: Bone Joint J 2013;95-B:1450–2.

Femoral revision after cemented total hip replacement (THR) might include technical difficulties, following essential cement removal, which might lead to further loss of bone and consequently inadequate fixation of the subsequent revision stem.

Femoral impaction allografting has been widely used in revision surgery for the acetabulum, and subsequently for the femur. In combination with a primary cemented stem, impaction grafting allows for femoral bone restoration through incorporation and remodelling of the impacted morsellized bone graft by the host skeleton. Cavitary bone defects affecting meta-physis and diaphysis leading to a wide femoral shaft, are ideal indications for this technique. Cancellous allograft bone chips of 1 mm to 2 mm size are used, and tapered into the canal with rods of increasing diameters. To impact the bone chips into the femoral canal a prosthesis dummy of the same dimensions of the definitive cemented stem is driven into the femur to ensure that the chips are very firmly impacted. Finally, a standard stem is cemented into the neo-medullary canal using bone cement.

To date several studies have shown favourable results with this technique, with some excellent long-term results reported in independent clinical centres worldwide.

Cite this article: Bone Joint J 2013;95-B, Supple A:92–4.