Good to excellent long-term survival of a single-design condylar constrained knee arthroplasty for primary and revision surgery.

PURPOSE: The purpose of the study was to determine the long-term survivorship, functional outcomes of a single-design condylar constrained (CCK) TKA in primary and revision cases as well as to assess specific risk factors for failure. It was hypothesized that primary CCK TKA had a better survival than revision knees. METHODS: One hundred and forty three patients who underwent revision TKA (n = 119) or complex primary TKA (n = 24) using a single-design condylar constrained knee system (Genesis CCK, Smith & Nephew) performed at a single institution between 1999 and 2008 were retrospectively included. The median follow-up amounted to 11.8 years (IQR 10.3-14.4). Implant survivorship was analyzed using Kaplan-Meier survival estimates and multivariate Cox regression analysis to identify risk factors for failure. Function was determined using the Oxford Knee Score (OKS). RESULTS: The implant survival was 86.4% after five, 85.5% after ten and 79.8% at 15 years. A reduced implant survivorship was found in males (HR 5.16, p = 0.001), smokers (HR 6.53, p = 0.004) and in obese patients (HR 2.26, p = 0.095). Patients who underwent primary TKA had a higher revision-free implant survivorship compared to revision TKA at 15 years (100% vs. 76%, p = 0.036). The main cause for re-revision was infection in 10% of all revision TKA performed with the CCK design included, while no case was revised for instability. The median OKS was 39 (IQR 35-44) in 102 patients available for long-term functional outcome. CONCLUSION: CCK implants are associated with excellent long-term survival when used in primary TKA; however, survival was worse when used during revision TKA. Males, smokers, obese patients and are at higher risk for revision. While instability and aseptic loosening were rare, infection remains a major concern. LEVEL OF EVIDENCE: Level IV, retrospective observational study.

siRNA mediated knockdown of tissue factor expression in pigs for xenotransplantation.

Acute vascular rejection (AVR), in particular microvascular thrombosis, is an important barrier to successful pig-to-primate xenotransplantation. Here, we report the generation of pigs with decreased tissue factor (TF) levels induced by small interfering (si)RNA-mediated gene silencing. Porcine fibroblasts were transfected with TF-targeting small hairpin (sh)RNA and used for somatic cell nuclear transfer. Offspring were analyzed for siRNA, TF mRNA and TF protein level. Functionality of TF downregulation was investigated by a whole blood clotting test and a flow chamber assay. TF siRNA was expressed in all twelve liveborn piglets. TF mRNA expression was reduced by 94.1 ± 4.7% in TF knockdown (TFkd) fibroblasts compared to wild-type (WT). TF protein expression in PAEC stimulated with 50 ng/mL TNF-α was significantly lower in TFkd pigs (mean fluorescence intensity TFkd: 7136 ± 136 vs. WT: 13 038 ± 1672). TF downregulation significantly increased clotting time (TFkd: 73.3 ± 8.8 min, WT: 45.8 ± 7.7 min, p < 0.0001) and significantly decreased thrombus formation compared to WT (mean thrombus coverage per viewing field in %; WT: 23.5 ± 13.0, TFkd: 2.6 ± 3.7, p < 0.0001). Our data show that a functional knockdown of TF is compatible with normal development and survival of pigs. TF knockdown could be a valuable component in the generation of multi-transgenic pigs for xenotransplantation.

[Bone defect reconstruction in bone sarcoma surgery: tumour endoprosthesis versus biological reconstruction]. / Rekonstruktion knöcherner Defekte in der Knochensarkomchirurgie: Tumorendoprothese vs. biologische Rekonstruktion.

BACKGROUND: Primary bone sarcomas typically arise in the long bones and the pelvis of children and adolescence but may also occur in adults. Meta/diaphysial tumour involvement resulting in the necessity of a joint replacement is more common than diaphysial tumour sites. AIM: In the treatment of these tumours, both endoprosthetic replacement and biological reconstruction techniques are used. Each technique has method-specific advantages and disadvantages. RESULTS: To choose the appropriate surgical method, a multitude of influencing parameters need to be considered. The age at treatment (soft tissue situation/estimated growth/biological potential of the bone), therapeutic concept (palliative vs. curative), the tumour site (upper/lower extremity), tumour expansion (diaphysis/metaphysis) and oncological treatment concept (chemotherapy/radiotherapy) are key factors significantly influencing the surgical technique in terms of functional outcome and longevity of the reconstruction. CONCLUSION: Surgical treatment of bone sarcoma requires broad-based experience of the oncological surgeon. Knowledge of the different surgical technics and reconstruction methods is decisive to offer the individual patient the best oncological and functional outcome.

[Management of complications in megaprostheses]. / Komplikationsmanagement bei Megaprothesen.

BACKGROUND: Megaprostheses are frequently used after segmental resection of bone sarcomas, bone metastases, and in large osseous defects in revision arthroplasty. OBJECTIVES: The incidence of the most common complications associated the use of megaprostheses are reported. The management of complications including therapeutic recommendations are described. MATERIALS AND METHODS: The current knowledge and our own experience of complication management with the use of megaprostheses are presented. RESULTS: Prospective, randomized studies or meta-analyses on this topic are lacking. An analysis of the literature shows that beside the occurrence of a local recurrence, periprosthetic infection remains the most serious complication. Two-stage revision remains the gold standard, but a single-stage exchange of the prosthesis without removing the stems might be possible in selected cases. Infection is associated with a higher risk of secondary amputation. In contrast, mechanical failures (e.g., wear of the bushings in knee replacements and aseptic loosening of the stems) can be treated more easily. Dislocation of a proximal femur replacement can mostly be prevented by using bi- or tripolar cups. CONCLUSIONS: Complications with the use of megaprostheses can be successfully treated by revision surgery in most cases.

[Attachment tube for soft tissue reconstruction after implantation of a mega-endoprosthesis]. / Der Anbindungsschlauch zur Weichteilrekonstruktion nach Megaprothesenimplantation.

OBJECTIVE: To restore function and an active range of motion, and stabilize the joint after joint resection. INDICATIONS: Restoration of a joint capsule following reconstruction of a defect using a proximal humerus and femur prosthesis. Reattachment of tendons and muscles. CONTRAINDICATIONS: Acute or chronic infection. Status after cured infection. SURGICAL TECHNIQUE: The attachment tube (Implantcast, Buxtehude, Germany) is attached to the joint capsule (proximal humerus and femur replacement) or directly to the prosthesis (for proximal tibial replacements) using nonresorbable Ethibond® sutures (Johnson & Johnson Medical, Norderstedt, Germany). Bone anchors are used, if the joint capsule has been completely resected. The body of the prosthesis, which has previously been attached to the shaft, is then pulled distally through the tube, and a (bipolar) head or humerus cap is placed on top of it. In the proximal humerus and femur replacement, proximal slitting of the tube may be helpful to reposition the prosthesis under vision. Following repositioning, fixation of the tube is completed ventrally and the slits previously made in the tube are sutured. Fixation of the tube to the prosthesis is carried out either with Ethibond® sutures placed around the tube, or--for a proximal humerus and tibia replacement--it is possible to attach suture material to the prosthesis through eyelets. POSTOPERATIVE MANAGEMENT: Further treatment basically depends on the location of the mega-endoprosthesis used. RESULTS: Macroscopically and microscopically, fibroblasts migrate into the tube's mesh, so that attachment of the soft tissue takes place. As of yet, no cases of luxation have occurred when the tube is used in combination with a bipolar head, and with fixed-implant cups the risk of luxation can be reduced using tripolar cup systems. In patients with a proximal tibial replacement, active straightening of the knee joint can be restored in most cases, although some limitation on active extension is still possible depending on the extent of the tumor resection.

The treatment of locally recurrent chondrosarcoma: Is extensive further surgery justified?

The aim of this study was to define the treatment criteria for patients with recurrent chondrosarcoma. We reviewed the data of 77 patients to examine the influence of factors such as the intention of treatment (curative/palliative), extent of surgery, resection margins, status of disease at the time of local recurrence and the grade of the tumour. A total of 70 patients underwent surgery for recurrent chondrosarcoma. In seven patients surgery was not a viable option. Metastatic disease occurred in 41 patients, appearing synchronously with the local recurrence in 56% of cases. For patients without metastasis at the time of local recurrence, the overall survival at a mean follow-up after recurrence of 67 months (0 to 289) was 74% (5 of 27) compared with 19% (13 of 50) for patients with metastasis at or before the development of the recurrence. Neither the type/extent of surgery, site of tumour, nor the resection margins for the recurrent tumour significantly influenced the overall survival. With limited survival for patients with metastatic disease at the time of local recurrence (0% for patients with grade III and de-differentiated chondrosarcoma), palliative treatment, including local radiation therapy and debulking procedures, should be discussed with the patients to avoid long hospitalisation and functional deficits. For patients without metastasis at the time of local recurrence, the overall survival of 74% justifies an aggressive approach including wide resection margins and extensive reconstruction.

Cartilage replacement in dogs -- A preliminary investigation of colonization of ceramic matrices.

The objective of this study was to examine the behaviour of canine chondrocytes following colonisation of a beta-tricalcium phosphate (beta-TCP, Cerasorbâ, Curasan) matrix. In total, five of these cylinders were inoculated with 1.5 ml of cell suspension and subsequently incubated for about one week. In the second part of the experiment, another five Cerasorbâ cylinders were each studded with two cartilage chips of variable size and then incubated for about one week. The series of experiments were analyzed using cell staining and imaging techniques that included scanning electron microscopy. Cell migration onto the matrix was proven for both colonisation methods. It was observed that colonising the cylinders by pipetting cell suspension on them produced far better results, with respect to both growth rate and spreading of the cells, than did colonisation by studding with cartilage chips. A homogenous, surface-covering colonisation with predominantly living cells was demonstrated by scanning electron microscopy in the chondrocyte morphology. In comparison to cell-culture controls, there was a clearly better colonisation, with cells attached to both the material's primary grains and its micropores. The ceramic studied is well accepted by canine chondrocytes, and appears to be fundamentally well-suited as a matrix for bio-artificial bone-cartilage replacement. Additional qualitative analyses and a series of experiments aiming to accelerate cell proliferation are planned for subsequent studies.

[Proximal femur replacement in revision arthroplasty]. / Der proximale Femurersatz in der Revisionsalloarthroplastik.

AIM: Today, megaendoprostheses--which were originally designed for osseous defect reconstructions in tumour surgery--are being more frequently used for extensive bone defects in revision arthroplasty. The purpose of this study was to assess the complication rate and the functional results associated with megaendoprosthesis reconstruction of the proximal femur in a non-oncological patient group. METHOD: 28 patients (average age 72; SD 10 years) with a proximal femur replacement were retrospectively (mean follow-up 43 months) evaluated regarding the complication rate. The Harris hip score was used to assess the outcome. The revision surgery was indicated because of large bone defects caused by implant-associated infection (n = 16), periprosthetic fracture (n = 8) or aseptic loosening (n = 4). RESULTS: Overall 8 patients (28.6 %) had to undergo 1 (n = 5) or more (2 n = 2, 4 n = 1) revision surgeries because of dislocation (n = 4), aseptic loosening of the stem (n = 2) and periprosthetic infection (n = 2). A significant pain relief could be achieved from on average 9.0 to 38.7 (according to the Harris hip score). All patients could be mobilised postoperatively, but walking aids were necessary for the majority of patients. CONCLUSION: A proximal femur replacement in revision arthroplasty should be regarded as a salvage procedure for restoration of extremity function. With this procedure it is possible to achieve a--limited--walking ability for patients who were immobilised preoperatively in most cases. Furthermore, pain relief can be achieved. However, the--mostly multimorbid--patients must be informed preoperatively about restrictions in daily life in order to avoid exorbitant expectations.

Bundle formation in polyelectrolyte brushes.

Bundle formation of the vertically oriented polyelectrolytes within polyelectrolyte brushes is studied with x-ray reflectivity and grazing-incidence diffraction as a function of grafting density and ion concentration. At 0.8 Molar monomer concentration and without added salt, a bundle consists of two chains and is 50 A long. On the addition of up to 1M CsCl, the aggregation number increases up to 15 whereas the bundle length approaches a limiting value, 20 A. We suggest that the bundle formation is determined by a balance between long-ranged electrostatic repulsion, whose range and amplitude is decreased on salt addition, and short-ranged attraction.

[Treatment of acute and chronic osteomyelitis in children]. / Behandlung von akuter und chronischer Osteomyelitis im Kindesalter.

AIM: Different studies in the past have reported about the treatment of osteomyelitis. None of these analysed the long-term results and complications after surgical treatment of acute and chronic osteomyelitis. The aim of this study was to analyse the recurrence rate and sequelae of osteomyelitis patients. PATIENTS AND METHODS: We analysed 53 children who were treated surgically between 1992 and 2004 for acute (n = 13) and chronic (n = 40) osteomyelitis. The histopathology was used for differentiation. With an average follow-up of 7.1 years (2 - 12.5 years) we examined the recurrence rate and the medical condition. RESULTS: A causative organism was identified in 53.9 % of the children with acute (AOM) and in 17.5 % of the children with chronic osteomyelitis (COM). In most cases Staphylococcus aureus could be isolated. Local antibiotics were applied intraoperatively to 92.3 % of the children with AOM and to 90 % of the children with COM. Additionally, the children with AOM were treated for 56.7 days (14 - 104 days) and the children with COM for 49.1 days (6 - 130 days) with parenteral/oral antibiotics. 2 (15.4 %) children with AOM and 6 (15 %) children with COM had a recurrence. At the time of the last examination all children were free of recurrence. One of the patients with AOM had a painless motion deficit of the shoulder. 5 children with COM complained of either pain and reduced range of motion of the affected extremity or minor deformities. CONCLUSION: Infantile osteomyelitis requires a selective diagnostic approach and an immediate parental antibiosis. If the antibiotic treatment fails, abscesses or sequestra are formed, an operation is indicated. With an adequate multidisciplinary cooperation, recurrence and sequelae can be avoided.

[Overlooked osteosarcoma in a patient undergoing total knee arthroplasty. A case report]. / Knieendoprothesenimplantation bei übersehenem Osteosarkom. Ein Fallbericht.

A 72-year-old woman presented with pain, swelling, and decreased range of motion of the left knee joint after total knee arthroplasty in 2005. We performed standard x-rays, which were highly suspicious for an osteosarcoma of the distal femur; this was proven by open biopsy. Retrospectively, the x-rays taken before implantation of the prosthesis showed suspicious findings. Because the femur was tumor-contaminated, with the intramedullary adjustment far-reaching proximally, a limb salvage procedure was no longer possible. To improve function, we decided to perform a stump-lengthening procedure using a special implant. With regard to the dismal consequences, we recommend that every suspicious finding before an elective surgical procedure be examined with further diagnostics and, if necessary, histological confirmation.

[Cartilage tumours of the bone. Diagnosis and therapy]. / Knorpelbildende Knochentumore. Diagnose und Therapie.

Primary malignant bone tumours are rare. The annual incidence of these tumours is 10 per 1 million. Nearly 30% of the primary malignant bone tumours are malignant cartilage tumours. The frequency of benign cartilage tumours cannot be definitely estimated because these tumours are normally clinically inapparent and therefore often diagnosed as an incidental finding. The cartilage tumours appear as benign lesions (e.g. chondroma), as borderline tumours (proliferative chondroma vs grade I chondrosarcoma) or as highly malignant chondrosarcoma (e.g. dedifferentiated chondrosarcoma). Commensurate with the different clinical and oncological manifestations of the cartilage tumours, there are wide differences in the treatment and clinical course of the individual tumour. This article discusses the problems in the diagnosis and treatment of cartilage tumours from an orthopaedic point of view.

Characteristics and outcome of infections associated with tumor endoprostheses.

INTRODUCTION: Infection associated with prosthesis used after tumor resection is a common and serious complication. The purpose of the current retrospective study was to describe the course of infection in patients with a tumor endoprosthesis and the determination of risk factors associated with failed limb salvage. MATERIAL AND METHODS: 30 patients with an infection associated with a tumor endoprosthesis were investigated with regard to treatment strategies, number and type of revision operations, duration of hospital stay, determination of risk factors associated with failed limb salvage and final outcome. RESULTS: Limb salvage related to the complication infection was achieved in 19 patients (63.3%). Two-stage reimplantation of an endoprosthesis was successful in 14 patients but subsequently failed in one patient. Out of 11 patients where limb salvage failed, an amputation was performed in 6 patients, a rotationplasty in 4, and stump lengthening procedure in 1 patient. A poor soft tissue condition was a significant (P<0.05) risk factor for failed limb salvage. No patient receiving chemotherapy with a poor soft tissue condition had limb salvage surgery. The mean number of revision operations per patients was 2.6. The mean duration of hospital stay was 68 days. CONCLUSION: Infection associated with prosthesis is a serious complication and is involved with long hospitalization. Limb salvage failed mostly in the case of a poor soft tissue condition. In these cases repeated revision surgery should be avoided and ablative surgery recommended at an early stage. Rotationplasty is an alternative to amputation in the case of an infection of the proximal or distal part of the femur.

Treatment of primary malignant bone tumours of the distal tibia.

We treated 15 patients with primary malignant bone tumours of the distal tibia of which 14 were treated by limb salvage surgery. Reconstructions were done by allografts with or without microvascular fibula transfer, by bone transport, by fibula transfer alone or by endoprosthetic replacement. The most successful methods were bone transport and endoprosthetic replacement. However, serious complications with deep infections leading to secondary amputation occurred in four patients and in all reconstruction groups. After a mean follow up of 7 years, no local recurrence occurred, and all patients were alive and free of disease. After radical resection, bone transport in defects less than 15 cm is a viable option. In larger defects in children, allograft with vascularised fibula is an acceptable alternative, but amputation still has a role in this group. In adults, endoprosthetic replacement with proper soft tissue coverage is a viable option in cases with large bony defects.

Rotationplasty type BI versus type BIIIa in children under the age of ten years. Should the knee be preserved?

Type BI rotationplasty is currently indicated for children with tumours of the proximal femur whereas type BIIIa rotationplasty is reserved for those in which the entire femur has to be removed. Our aim was to compare these two types of rotationplasty and determine whether the knee should be preserved in children with tumours of the proximal femur. We compared the post-operative complications, oncological outcome, range of movement, Enneking score and radiographs of six children, who had undergone type BI rotationplasty with those of 12 who had undergone type BIIIa rotationplasty. Patients with type BI rotationplasty had a mean Enneking score of 21.6 compared with 24.4 in those with type BIIIa rotationplasty, and worse mean results in all of the parameters investigated. We conclude that type BI rotationplasty has a worse functional outcome and more complications than type BIIIa rotationplasty in children under the age of ten years.

Endoprosthetic replacement of the humerus combined with trapezius and latissimus dorsi transfer: a report of three patients.

INTRODUCTION: To improve the functional outcome after proximal and/or total humerus replacement, we combined the surgical procedures described by Bateman and Gerber. MATERIALS AND METHODS: In three patients after wide tumor resection, endoprosthetic replacement with a modular tumor endoprosthesis (MUTARS System) was performed. In addition to a capsular and muscular reconstruction using the Trevira tube, a trapezius transfer onto the Trevira tube in combination with a latissimus dorsi transfer onto the Trevira tube was performed. The patients were immobilized for 6 weeks after surgery with an abductor cast. RESULTS: After a follow-up of 1 year, there was no significant improvement of the shoulder function in comparison with patients who did not undergo the combined muscle transfer (control group n=16: mean abduction 37.5 degrees ; mean anteversion 35.0 degrees ; mean internal rotation 15.2 degrees ; mean external rotation 25.2 degrees ). CONCLUSION: In our patients, the combination of the Gerber and the Bateman procedures did not improve the shoulder function in patients with proximal and/or total humerus replacements. Therefore, the functional results do not justify two separate approaches and a prolonged operation time.

Primary multifocal osseous Hodgkin disease: a case report and review of the literature.

PURPOSE: Hodgkin disease (HD) typically involves the lymphatic system at one or more sites. Rarely, Hodgkin disease presents as an osseous lesion without involvement of lymph nodes. Therefore, the histologic diagnosis of osseous HD can be problematic. We present a rare case of multifocal osseous HD and a review the literature with special emphasis on treatment and prognosis. METHODS: Osteomyelitis and lymphoma are the main differential diagnoses and can only be excluded histologically by the presence of Sternberg Reed cells or by immunohistochemical examinations. This case reports a 21-year old man with a Hodgkin lymphoma located at the proximal femur and the proximal tibia. RESULTS: Staging studies revealed no other tumor manifestations. Regarding the Ann Arbor classification, the presented case should be a stage IV disease. The patient is without evidence of disease 4 years after curettage, local radiation therapy, and systemic chemotherapy despite the poor prognosis considering the Ann Arbor classification. CONCLUSION: Reviewing the few reported cases, osseous HD must be distinguished from systemic HD with diffuse bone marrow involvement and from osseous metastases in advanced stage of disease because it seems to have a better prognosis.

Modelling of the biodegradation of organic matter in municipal landfills.

A model is presented to simulate the biodegradation of easily and slowly hydrolyzable organic matter, as well as the generation of biogas and heat release. The model is based on fundamental relationships among physical/chemical, thermodynamical and microbial processes occurring in municipal landfills. Local, microbially-mediated degradation processes occurring in municipal landfills, are simulated in terms of the hydrolysis of solid organic matter, the formation of glucose and acetate as intermediary carbon substrates and the generation of the biogases CH4 and CO2. Thus, the overall decomposition of the organic matter has been assumed to follow four sequential biochemical reactions: hydrolysis, acidogenesis, acetogenesis and methanogenesis. In order to study the impact of environmental factors on the biological decomposition processes, pH, temperature and hydrogen changes have been integrated into the degradation model as inhibition terms.

Transgenic mice overexpressing protein kinase Cdelta in the epidermis are resistant to skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate.

To determine the role of protein kinase Cdelta in mouse skin carcinogenesis, we have developed transgenic FVB/N mouse lines expressing in the epidermis an epitope-tagged protein kinase Cdelta (T7-PKCdelta) regulated by the human keratin 14 promoter. The untreated T7-PKCdelta mice displayed excessive dryness in the skin of the tail with a variable penetrance over time. Histologically, the tail skin showed hyperplasia with evidence of hyperkeratosis. The epidermis of the rest of the T7-PKCdelta mouse was unremarkable. Despite this mild phenotype, the effects of PKCdelta overexpression on mouse skin tumor promotion by 12-O-tetradecanoylphorbol-13-acetate (TPA) were dramatic. Two independent lines of T7-PKCdelta mice (16 and 37) expressing the T7-PKCdelta transgene were examined for responsiveness to skin tumor promotion by 7,12-dimethylbenz[a]anthracene and TPA. By immunoblot analysis, the T7-PKCdelta-16 and T7-PKCdelta-37 mice showed an 8- and 2-fold increase of PKCdelta protein. The T7-PKCdelta-16 mice averaged 300% more T7-PKCdelta activity than the T7-PKCdelta-37 mice did. The T7-PKCdelta-37 mice did not manifest any difference in tumor burden or incidence. However, the reduction in papilloma burden at 25 weeks of promotion for the T7-PKCdelta-16 mice relative to wild-type mice averaged 72 and 74% for males and females, respectively. The T7-PKCdelta-16 mice reached 50% papilloma incidence between 12 and 13 weeks of promotion compared with 8 weeks for wild-type mice. Furthermore, the carcinoma incidence was also reduced in T7-PKCdelta-16 mice. Carcinoma incidence at 25 weeks of promotion treatment was: wild-type females, 78%; T7-PKCdelta16 females, 37%; wild-type males, 45%; and T7- PKCdelta-16 males, 7%. Thus, PKCdelta when expressed at sufficient levels can suppress skin tumor promotion by TPA.