Mid-term results after revision total hip arthroplasty with custom-made acetabular implants in patients with Paprosky III acetabular bone loss.

INTRODUCTION: Severe acetabular bone loss, both with or without pelvic discontinuity, remains a challenge in revision total hip arthroplasty (RTHA). The goal of our study was to evaluate the mid-term results for consecutive patients with Paprosky III acetabular bone loss with or without pelvic discontinuity who needed RTHA with custom-made acetabular implants and to compare the results to those of other studies. MATERIALS AND METHODS: Sixty-eight (68) patients with severe acetabular bone loss (Paprosky Type IIIa and IIIb), who required RTHA, were included in our study. All prostheses were constructed on the basis of thin-layer computed tomography (CT) scans of the pelvis. The visual analogue scale (VAS), Harrison hip score (HHS), and clinical and radiographic follow-up assessments were used to evaluate the outcome. RESULTS: The average follow-up time was 43 months (range 1-120 months). Implant survival at last follow-up was 75% (51 of 68). Kaplan-Meier survival analysis, with explantation as the endpoint, revealed survival rates of 82.7% (3 years) and 77% (5 years). Patients with revision of the acetabular component only had a significant higher survival rate (p 0.012). Overall revision rate was 36.7%. Reinfection rate was 34.4%. Complications included 15 (22%) periprosthetic joint infections (PJI), 7 dislocations (10.2%), and 2 aseptic loosenings (2.9%). Mean VAS at last follow-up was 1.45 compared to 3.2 preoperatively, while mean HHS improved from 21.1 points preoperatively to 61 at last follow-up. The change in both scores was thus significant (p < 0.001). CONCLUSION: Defect reconstruction with custom-made modular acetabular implants can be a good, nevertheless expensive, treatment option with clinically and radiologically satisfying results in comparison to recent studies in the literature. Nevertheless, high postoperative complication rates, especially in terms of PJI, remain a challenge.

Analysis of synovial biomarkers with a multiplex protein microarray in patients with PJI undergoing revision arthroplasty of the hip or knee joint.

INTRODUCTION: Diagnosing a (low-grade) periprosthetic joint infection (PJI) after hip or knee arthroplasty remains a diagnostic challenge. The aim of this study was to evaluate the utility of using a novel multiplex protein microarray system for synovial biomarkers in determining PJI in patients undergoing revision knee or hip arthroplasty. MATERIALS AND METHODS: The individual synovial fluid levels of 12 cytokines (IL-1b, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-17, GM-CSF, TNF-α, and INF-γ) were analysed with a novel multiplex protein microarray system in 32 patients undergoing revision hip (n = 22) or knee (n = 10) arthroplasty. Cases were classified into septic and aseptic groups on basis of pre- and interoperative findings: [PJI (n = 14) vs. non-PJI (n = 18)]. Receiver operator characteristic (ROC) curves were calculated to assess the discriminatory strength of the individual parameters. A multiple regression model was used to determine the utility of using a combination of the tested cytokines to determine the infection status. RESULTS: The levels of all of the evaluated cytokines were significantly elevated in the PJI-group. Best sensitivity and specificity were found for IL-6, followed by IL-1b, IL-10, and IL-17. The multiple regression models revealed a combination of IL-2, IL-4, IL-5, IL6, lL-12, and GM-CSF to be associated with the best sensitivity (100%) and specificity (88.9%) for a cut-off value of 0.41, with a likelihood ratio of 9.0. CONCLUSION: Analysis of individual synovial fluid cytokine levels showed both high sensitivity and high specificity in diagnosing PJI. A combined model using several cytokines showed even higher sensitivity and specificity in diagnosing PJI and could thus be a useful predictive tool to determine the probability of PJI in patients with a painful prosthesis. LEVEL OF EVIDENCE: Diagnostic IV.

Osseous hydatidosis of the proximal femur: a rare diagnosis in revision total hip arthroplasty.

Musculoskeletal hydatidosis is a rare but severe disease in central Europe. This case report presents the incidental finding of an osseous hydatidosis after cementless revision total hip arthroplasty in a patient without a preoperative history of hydatidosis or any clinical symptoms. Revision total hip arthroplasty had been necessary due to a septic osteonecrosis of the femoral head 2 years after osteosynthesis of a traumatic proximal femur fracture with a sliding hip screw. The positive sample was taken out of the greater trochanter in the area of the possible former entry point for the lag screw, which was macroscopic inconspicuous. Sero-analysis could afterwards confirm the suspected diagnosis. Postoperative chemotherapy with albendazole was performed for 6 months. A full-body MRI did not reveal any further cysts. This case demonstrates a possible impact of migration on the expected pathogens in revision arthroplasty. This demonstrates that in revision arthroplasty, an infection with this parasite also has to be taken into account, if the patients come from an area endemic for hydatidosis.

[The S2k guideline: Indications for knee endoprosthesis : Evidence and consent-based indications for total knee arthroplasty]. / S2k-Leitlinie: Indikation Knieendoprothese : Evidenz- und konsensbasierte Indikationsstellung in der Knie-Endoprothetik (EKIT-Knie).

Total knee arthroplasty (TKA) is one of the most frequent surgical procedures in orthopaedic surgery. Until now there have not been any standardized indication criteria, which might contribute to the large geographical differences in the frequency of TKA. This guideline aims to consent minimal requirements (main criteria), additional important aspects (minor criteria), as well as relative and absolute contraindications for TKA. The following main criteria have been consented: knee pain, radiological confirmation of osteoarthritis or osteonecrosis, inadequate response to conservative treatment, adverse impact of knee disease on the patient's quality of life and the burden of suffering due to the knee disease. Relative contraindications have been consented as severe general disease with reduced life expectancy and a BMI ≥40; absolute contraindications are an active infection and if the patient is not able to undergo major surgery.

Lower limb reconstruction in tumor patients using modular silver-coated megaprostheses with regard to perimegaprosthetic joint infection: a case series, including 100 patients and review of the literature.

PURPOSE AND OBJECTIVE: Bone resection regarding adequate surgical margins is the treatment of choice for malignant bone tumors. In the case of metastasis-related complications, so-called skeletal-related events, it is highly important to achieve pain relief and a stable joint situation to re-mobilize the patients immediately following surgery. To bridge the often large osseous defect zones after tumor resection, both cemented and uncemented modular endoprosthetic systems are widely used. Patients undergoing tumor-related endoprosthetic orthopedic surgery are facing high risk for developing a periprosthetic joint infection (PJI). The immunocompromised condition due to anti-neoplastic treatment and long operation time with large exposure of tissue contributes to a high risk of infection. METHODS: The authors present a case series of 100 patients (31% primary bone tumor and 69% metastasis-related surgery) undergoing tumor-related lower limb salvage surgery with special regard to periprosthetic joint infection and the management of this "difficult to treat" situation. Furthermore, a review of the current literature regarding infection following bone tumor resection and endoprosthetic reconstruction is performed and discussed. RESULTS: The median follow-up was 24 months (range 12-108 months). Ten patients (10%) suffered from a periprosthetic joint infection. We recorded six acute infections (type I) <4 weeks after surgery, one infection >4 weeks after surgery (type II), and three late infections (type III). According to the definition of Laffer et al., three of our patients (30%) are probably free of infection, one patient died of PJI-associated sepsis, and five patients were free of infection, but without restoration of the affected joint. CONCLUSION: In conclusion, our own results show that perimegaprosthetic joint infection among silver-coated implants, in patients undergoing tumor-related surgery of the lower limb, is lower compared to non-silver-coated implants. Due to heterogeneity of patients and potential treatment options, the treatment regime should be tailored for the patients' individual situation.

[Biological downsizing : Acetabular defect reconstruction in revision total hip arthroplasty]. / Biologisches Downsizing : Azetabuläre Knochendefekte in der Hüftrevisionsendoprothetik.

BACKGROUND: Periacetabular bony defects remain a great challenge in revision total hip arthroplasty. After assessment and classification of the defect and selection of a suitable implant the primary stable fixation and sufficient biological reconstitution of a sustainable bone stock are essential for long term success in acetabular revision surgery. Biological defect reconstruction aims for the down-sizing of periacetabular defects for later revision surgeries. TECHNIQUE: In the field of biological augmentation several methods are currently available. Autologous transplants feature a profound osseointegrative capacity. However, limitations such as volume restrictions and secondary complications at the donor site have to be considered. Structural allografts show little weight bearing potential in the long term and high failure rates. In clinical practice, the usage of spongious chips implanted via impaction bone grafting technique in combination with antiprotrusio cages for the management of contained defects have shown promising long time results. Nevertheless, when dealing with craniolateral acetabular and dorsal column defects, the additional implantation of macroporous metal implants or augments should be considered since biological augmentation has shown little clinical success in these particular cases. PROSPECT: This article provides an overview of the current clinically available biological augmentation methods of peri-acetabular defects. Due to the limitations of autologous and allogeneic bone transplants in terms of size and availability, the emerging field of innovative implantable tissue engineering constructs gains interest and will also be discussed in this article.

Multidrug resistant Acinetobacter baumannii reaches a new frontier: prosthetic hip joint infection.

Acinetobacter baumannii is an emerging nosocomial pathogen primarily in countries with a high prevalence of multidrug resistance. Here we report the detection of a bla OXA23 carbapenemase-producing A. baumannii strain in a German patient with prosthetic hip joint infection following several hip joint surgeries but no history of foreign travel.

[Antimicrobial prosthesis coatings]. / Antimikrobielle Prothesenbeschichtungen.

BACKGROUND: Antimicrobial coatings have a great potential in the treatment and prevention of periprosthetic joint infection. OBJECTIVE: To present established and novel concepts of antimicrobial coatings. METHODS: A literature review and discussion of published concepts in basic research, pre-clinical animal studies, and clinical practice were carried out. RESULTS: To date there has been a wide range of technical solutions (anti-adhesive surfaces, bioactive surfaces with antimicrobial effects, surfaces releasing antimicrobial substances, nanostructures, bioactive surfaces affecting biofilm development) demonstrating a high potential in pre-clinical studies. Only a few with the bactericidal activity of silver ions have been prepared for the market. Conclusive results with regard to biocompatibility and toxicity are lacking. DISCUSSION: Despite the great potential of antimicrobial coatings, no conclusive decisions can be made because of the limited data and the lack of evidence of their clinical efficacy on the basis of prospective controlled clinical studies. In addition to their unlimited biocompatibility, innovative concepts have to be feasible in everyday clinical routine.

MALDI imaging of predictive ferritin, fibrinogen and proteases in haemophilic arthropathy.

Arthropathy as a result of repeated joint bleeding is a severe complication in patients with haemophilia. In the evaluation of synovial tissue specimens, histology alone is non-specific and there is considerable morphological overlap with other joint diseases. Formalin-fixed paraffin-embedded specimens are available in pathological institutes and can be studied to understand the pathogenesis of haemophilic arthropathy. A powerful technique to identify hundreds of proteins in a tissue section combining proteomics with morphology is imaging mass spectrometry (IMS). We determined whether matrix-assisted laser desorption/ionization (MALDI) IMS can be used to identify and map protein signatures in the synovial tissue of patients with haemophilic arthropathy. MALDI IMS was applied to synovial tissue of six patients with haemophilic arthropathy. We detected several peaks predictive in mass with ferritin light (m/z 1608) and heavy chain (m/z 1345), alpha- (m/z 1071) and beta (m/z 1274) haemoglobin subunits, truncated coagulation factor VIII peptide (m/z 1502, 1176), beta- and gamma fibrinogen peptides (m/z 980, 1032, 1117 and 1683), and annexin A2 (m/z 1111, 1268, 1460, 2164). In addition, the distribution of these proteins in synovial tissue sections was demonstrated. MALDI IMS identified and mapped specific proteins in the synovial membrane of patients with haemophilic arthropathy known to be involved in the pathogenesis of other joint diseases. This technique is a powerful tool to analyse the distribution of proteins in synovial tissue sections.

Total ankle replacement in patients with haemophilia and virus infections--a safe alternative to ankle arthrodesis?

Despite reliable results of ankle fusion for advanced haemophilic arthropathy, total ankle replacement (TAR) may be functionally advantageous. There is only very limited literature data available on TAR in patients with haemophilia. The objective of this study is to evaluate the short- and mid-term results after TAR in patients with end-stage haemophilic ankle arthropathy and concomitant virus infections. In a retrospective study, results after eleven TAR in 10 patients with severe (n = 8) and moderate (n = 2) haemophilia (mean age: 49 ± 7 years, range, 37-59) were evaluated at a mean follow-up of 3.0 years (range, 1.2-5.4). Nine patients were positive for hepatitis C, five were HIV-positive. Range of motion (ROM), AOFAS-hindfoot-score, pain status (visual analogue scale, VAS) as well as patient satisfaction were evaluated. In two cases deep prosthesis infection occurred leading to the removal of the implant. In the remaining eight patients the mean AOFAS score improved significantly from 21.5 to 68.0 points (P < 0.0005), the VAS score decreased significantly from 7.6 to 1.9 points (P < 0.0005). ROM increased from 23.2 to 25.0 degrees (P = 0.51). At final follow-up all patients without any complications were satisfied with the postoperative results. Radiographic examination did not reveal any signs of prosthetic loosening. TAR is a viable surgical treatment option in patients with end-stage ankle osteoarthritis due to haemophilia. It provides significant pain relieve and high patient satisfaction. However, due to the increased risk of infection and lack of long-term results, TAR particularly in patients with severe haemophilia and virus infections should be indicated carefully.

[The one- and two-stage distally pedicled sural flap : surgical technique and clinical results]. / Der ein- und zweizeitige distal gestielte Suralislappen : Operationstechnik und klinische Ergebnisse.

BACKGROUND: The distally pedicled suralis flap is used to cover local defects of the distal lower leg, ankle and hind foot. It is a local flap with no need for microvascular anastomosis, a constant blood supply and ease of elevation. Disadvantages are lack of sensation, donor site morbidity and venous congestion. METHODS AND MATERIAL: This study includes 25 patients. Apart from the defect extent, cause and location, complications were also determined. RESULTS: The defect site was located in the hind foot in 5 cases and the distal lower leg in 14 cases. In four patients the soft tissue of the lateral calcaneal region and in two cases the sole of the foot were affected. Severe venous congestion, which was only detected in 180° turned flaps, was seen in five cases. In five patients we successfully performed a two-stage flap transposition procedure to avoid venous congestion. CONCLUSION: The sural flap remains a reliable solution for soft tissue defects. Under inappropriate circumstances (small pedicle or severe torque of pedicle) venous congestion or even thrombosis is possible. A two-stage approach with conditioning of venous drainage can have a positive effect on these problems.

[What can be done when hip prostheses fail? : New trends in revision endoprosthetics]. / Was tun, wenn die Hüftendoprothese versagt? : Neue Trends in der Revisionsendoprothetik.

Revision surgery after total hip arthroplasty is increasing steadily in numbers. These procedures demand high performance from both the treating surgeon as well as the implants used. Novel developments from basic research and industrial partners extend the possibilities for treating affected patients. This article gives an overview of the state of the art in revision hip arthroplasty: new techniques and trends are outlined and presented.

[Homo erectus haemophilus - the haemophilic arthropathy of the leg]. / Homo erectus haemophilus. Die hämophile Arthropahtie der unteren Extremität.

The haemophilic arthropathy of the hip, the knee and the ankle makes a painful loss of the degree of movement. Especially the muscles which bend these joints are contracted. This means a loss of posture and quality of life as well. This article demonstrates the possibilities of the conservative and operative treatment and represents an algorithm of the indication of operative measurements. Finally, there is a report about the straighten up and the re-socialisation of a patient with haemophilia by total hip and knee arthroplasty.

Evaluation of a new fluoroscopy-based navigation system in the placement of the femoral component in hip resurfacing.

Prosthesis-specific mechanical alignment instruments for the precise and reproducible positioning of the femoral component constitute one of the major improvements in modern hip resurfacing prostheses. However, mechanical failure of the femoral component is mostly attributable to the surgical technique, and in particular to notching of the femoral neck. In order to evaluate a novel computer-assisted fluoroscopy-based planning and navigation system, six DUROM hip resurfacing prostheses were implanted into artificial femurs by means of computer-assisted fluoroscopy-based navigation and prosthesis-specific mechanical alignment instruments. Subsequently, the planning and navigation system was tested within the scope of a cadaver study on three fixed whole-body preparations (six femurs). The average difference between planned and actual angle of the prosthesis was 0 +/- 0.7 degrees for fluoroscopy-based navigation versus 6.5 +/- 7.8 degrees for the in-vitro use of the prosthesis-specific mechanical alignment instruments, and 1 +/- 1.4 degrees for fluoroscopic navigation in the cadaver study. The average discrepancy between planned and actual anterior offset was -1.2 +/- 1.2 mm versus 0.8 +/- 4 mm, and 0.3 +/- 2.2 mm in the cadaver study, and the time required for the total of five planning and navigation steps was 17.2 +/- 1.5 min versus 14 +/- 0.8 min and 20.2 +/- 2.5 min respectively. No notching of the femoral neck occurred under fluoroscopy nor under conventional treatment. During in-vitro studies, use of the computer-assisted fluoroscopy-based planning and navigation system resulted in enhanced accuracy compared with conventional prosthesis-specific mechanical alignment instruments. The system has yielded initial promising results within the scope of the cadaver study.

[Endoprosthesis for the fractured elbow: uni- and bicompartmental alloarthroplasty of the humero-ulnar joint]. / Frakturendoprothetik am ellenbogen: uni- und bikompartimentelle alloarthroplastik am humeroulnaren gelenk.

Posttraumatic arthrosis or rheumatoid arthritis located at the elbow, in particular at the humero-ulnar joint will probably not occur in increasing numbers in the future due to new antirheumatic medications and modern implants. However, the demographic development with an increase of the geriatric population and the typical physical changes is evident. Due to osteoporosis with a resulting poor bone quality severe fracture patterns may occur at the site of the distal humerus after a simple collapse. The usual surgical aim consisting of an exact anatomic reduction may be impossible to achieve by applying the standard operative treatment. Several studies have proven that a prosthetic replacement of such a severely damaged elbow is a viable solution for elderly people. A mobile, pain-free and stable elbow joint promotes a fast recovery of the patient with a quick return to former activities. Nevertheless, elbow prostheses cannot withstand great strains and the surgeon has to identify those fractures which require a prosthetic replacement. The surgical implantation procedure requires an adequate knowledge of both elbow anatomy and prosthetic options.

[Algorithm for the treatment of the haemophilic arthropathia of the upper ankle joint]. / Behandlungsalgorithmus der hämophilen Arthropathie des oberen Sprunggelenkes.

The upper ankle joint is one of the target-joints of the haemophilic patient. Therefore, the secondary arthritis of the upper ankle joint is one of the most frequent forms of haemophilic arthropathy. It is a secondary form of arthritis not only because of chronic synovitis and cartilage injury resulting from chronic recurrent intraarticular bleeds, but also due to the misalignment of the joint and abnormal joint stress. The consequences are manifest even in young patients and finally lead to upper ankle joint arthritis. In such clinical situations, the upper ankle joint-arthroplasty is a viable alternative to arthrodesis. After several years of bleeding of the upper ankle joint many patients with haemophilia suffer from symptomatic arthritis. Open joint cleansing considerably improves mobility in the upper ankle joint and alleviates the pain in the talonavicular joint. However, the recovered mobility of the arthritic upper ankle joint also activates arthritis, associated with severe pain. With no contraindication to upper ankle joint replacement, a cement-free prosthesis can be implanted. Three months after surgery, the patients are mobile, with good foot rolling properties without orthopaedic aids and without pain in the upper joint ankle. Concludion: In terms of biomechanics the upper ankle joint-arthroplasty is a superior alternative to arthrodesis in haemophilia patients. In order to minimize the complication rate, their treatment should be restricted to specially equipped interdisciplinary centers with adequately trained and experienced surgeons as well as haemostaseologists.

[Acetabular revision arthroplasty with a novel cementless augment-and-modular-cage system (MRS-C) : Surgical technique and preliminary clinical results]. / Hüftpfannenwechsel mit einem neuartigen zementfreien "Augment-and-modular-cage"-Revisionssystem (MRS-C) : Chirurgische Technik und erste klinische Ergebnisse.

OBJECTIVE: Optimal reconstruction of acetabular anatomy and primarily stable bridging even of large bone defects in hip revision surgery by intraoperative cementless application of highly modular components of the MRS-TITAN Comfort (MRS-C) system according to the augment-and-modular-cage principle. INDICATIONS: Acetabular defect situations in hip revision surgery, hereditary/acquired acetabular deformities, severe secondary hip osteoarthritis. CONTRAINDICATIONS: Extended periacetabular defects of the dorsal pillar, pelvic discontinuities, persisting posttraumatic or periprosthetic infections, lack of intraoperative bony anchorage options. SURGICAL TECHNIQUE: Conventional positioning. Flexible selection of approach (posterolateral, anterolateral or transgluteal) to the hip joint, if possible using a previous approach. Implant removal, preparation and intraoperative acetabular defect evaluation. Optional impaction bone grafting for biological downsizing. Selection of modular components and augments depending on the defect. Preparation of the obturator foramen for anchorage of the caudal flange. Optional preparation of the os ilium for additional fixation of the cage with flanges. Fixation with polyaxial screws and selection of version/inclination of the cup component. Selection of the inlay (polyethylene/ceramic). POSTOPERATIVE MANAGEMENT: Partial weight-bearing with 20 kg body-weight for 6 weeks with crutches. Prophylaxis for deep vein thrombosis and heterotopic ossification. Additional adapted antibiotic therapy in cases of infection. RESULTS: A minimum 1­year follow-up of 42 patients showed significant improvements of Harris Hip Scores (p < 0.0001), adequate reconstruction of the physiologic center of rotation (x-ray controlled in the vertical plane, referenced to the contralateral side), and a clear reduction of preoperative leg length discrepancies. No significant changes in range of motion. No implant-associated complications noted. Based on the short follow-up results, the implant proves as suitable for reconstruction of even large acetabular bone defects.

[Periprosthetic fractures of the acetabulum: revision endoprosthetics]. / Periprothetische Frakturen des Acetabulums: Revisionsendoprothetik.

BACKGROUND: Periprosthetic acetabular fractures are an increasing severe complication in revision arthroplasty. A differentiation is made between periprosthetic acetabular fractures (acute/traumatic fractures) and insufficiency fractures (chronic fractures). OBJECTIVE: This article introduces a novel treatment algorithm that provides assistance in therapeutic decision making for implant selection and the anchoring philosophy based on diagnostic decision criteria and the relevant load-bearing osseous structures, taking the defect situation into account. MATERIAL AND METHODS: The article provides an overview of original and review articles. RESULTS: The essential criteria for decisions in treatment planning are based on the stability of the primary cup, the load-bearing ability of the main anatomical structures and the resulting defect situation. For insufficiency fractures the reason for the revision and therefore the exclusion of periprosthetic joint infections (PJI) must additionally be considered. In the case of proven PJI a two-stage or multistage prosthesis exchange must be carried out. Based on the extent of apparent bony defects and pelvic discontinuity, the spectrum of treatment options ranges up to implantation of individual patient custom-made acetabular components. DISCUSSION/CONCLUSION: This overview introduces a new treatment algorithm that provides assistance in decision making for traumatic periprosthetic acetabular fractures and insufficiency fractures. It also provides decision criteria for selection of implants and the surgical approach. Due to the complexity of revision arthroplasty often requiring specialized expertise in trauma and orthopedic surgery and experienced revision surgeons, the operative treatment of periprosthetic acetabular fractures should only be carried out in specialized orthopedic and trauma surgery centers with appropriate experience.

[Use of an new modular revision arthroplasty system for the knee reconstruction]. / Einsatz eines neuen modularen revisionsendoprothetischen Systems zur Kniegelenksrekonstruktion.

OBJECTIVE: Reconstruction of stable knee joint kinematics using modular axis-guided revision implants after failed knee arthroplasty surgery. INDICATIONS: Revision implant for bone defects (type Anderson Orthopaedic Research Institute [AORI] III) in case of revision arthroplasty. Primary implant in case of mediolateral instability (>grade I) or multidirectional instability. CONTRAINDICATIONS: Persistent or current joint infection, general infection (e.g. pneumonia), missing metaphysis femoral and/or tibial, insufficient extensor apparatus. SURGICAL TECHNIQUE: Standard approach extending the previously used skin incision. Arthrotomy, synovectomy and collection of multiple samples for microbiological and histopathological analyses. Preparation of the femur with reamers of increasing diameter. Subsequently, a reference stem is anchored and after referencing the correct rotation and joint line height; the femoral osteotomy is performed after fixation of the 5­in­1 cutting block. Following the femoral osteotomy, the box of the femoral prosthesis is prepared. In addition, the tibia is prepared using an intramedullary reference system. Level of constraint and additional tibial augmentation is chosen according to the amount of defect bone and according to ligament stability. POSTOPERATIVE MANAGEMENT: Full load bearing; standard wound control and sterile dressings; limitation of active/passive range of motion only in case of weakened extensor apparatus. RESULTS: Between 03/2011 and 05/2018, a total of 48 patients underwent revision arthroplasty using the described system. The mean follow-up was 24 months (range 21-35 months). In 30 of the 48 cases, a rotating hinge variant was implanted, while in 18 cases a semiconstrained variant was implanted. Indications to revision arthroplasty: infection (n = 22), aseptic loosening (n = 11), instability (n = 11), periprosthetic fracture (n = 3) and PMMA allergy (n = 1). In 11 cases, revision had to be performed due to persistent infection (n = 6) and aseptic loosening (n = 5): 9 cases could be successful treated by a two-step revision procedure, while in 2 cases it was necessary to perform an arthrodesis. The 2­year implant survival rate was 77%.

[Modular arthrodesis system TITAN (KAM-TITAN) after failed revision total knee arthroplasty : Operative technique and clinical experience]. / Modulares Kniearthrodesesystem TITAN (KAM-TITAN) nach fehlgeschlagener Knieendoprothetik : Operative Technik und klinische Ergebnisse.

OBJECTIVE: Restoration of a painless, weight-bearing extremity with a modular knee arthrodesis system based on a cementless modular revision stem for rotationally stable, diaphyseal anchorage. INDICATIONS: Severe bone loss and compromised soft tissue after failed total knee arthroplasty, two-stage revisions and non-reconstructible knee extensor mechanism deficiency. CONTRAINDICATIONS: Extensive osteolysis preventing diaphyseal anchorage of the prosthesis. Contralateral arthrodesis of the knee joint and/or ipsilateral arthrodesis of the hip joint and contralateral lower extremity amputation. SURGICAL TECHNIQUE: In revision cases, removal of the total knee arthroplasty, spacer, the bone cement and all intramedullary granulation tissue. Reaming the medullary cavity with intramedullary reamers to cortical contact. Restoring leg length and rotation with trial implants. After implantation of the femoral and tibial stems, placing and tensioning of the rotationally aligned coupling elements. POSTOPERATIVE MANAGEMENT: Mobilization on two forearm crutches from postoperative day 1. Removal of the Redon drains after 48 h. Partial weight bearing of 20 kg for 6 weeks postoperatively. If plain radiographs show unchanged seating of the prosthesis after 6 weeks, loading can be increased by 10 kg per week until full weight bearing is achieved. RESULTS: Between 2007 and 2012 clinical data were collected and analyzed retrospectively. A total of 27 patients had been treated within a two-stage exchange procedure with implantation of a modular intramedullary arthodesis nail TITAN (KAM-TITAN). The mean follow-up was 30.9 ± 12.0 months. A functional evaluation was performed using the Oxford Knee Score (OKS). The analyzed patients showed a mean score of 39.2 ± 8.3. To determine the pain level the Visual Analog Scale (VAS) for pain was used and showed a mean score of 2.9 ± 1.3. The rate of definitely free of infection (using Laffer criteria) at last follow-up was 85.2%.