[Periprosthetic Infection of the Knee Megaprosthesis following a Resection of Malignant Tumours around the Knee]. / Periprotetické infekce megaprotéz po resekcích kostních nádoru oblasti kolene.

PURPOSE OF THE STUDY The study presents the monocentric retrospective study of a group of patients with malignant tumours around the knee, treated by a wide resection and a reconstruction with megaprosthesis due to infectious complications. Provided is a detailed analysis of each operative treatment due to the manifestation and process of periprostethic infection of the knee megaprosthesis and the use of external fixator during a two-stage revision. MATERIAL AND METHODS Between 01/1993 and 12/2013, a total of 67 cemented megaprostheses were assessed, with a detailed analysis of 12 patients with periprosthetic infection. The Kaplan-Meier method and MSTS for lower extremity clinical assessment were used and a range of motion was evaluated. RESULTS The endoprosthesis failed due to all kinds of complications (mechanical, biological, infection) in 27 (40.3%) patients. The estimated one-year survival rate from the surgery was 94%, the five-year survival rate was 72%, and the ten-year survival rate was 46%. Based on the statistical analysis of the implant survival due to infection, the one-year survival rate was 94%, the five-year survival rate was 75%, and the ten-year survival rate was 57%. Three patients were treated with radical surgical debridement. Five patients were treated with a two-stage revision with a cement spacer and external fixator, and three patients underwent nail fixation. Clinical values before and two years after the revision surgery for periprosthetic infection using MSTS were assessed. The mean of the difference of clinical values was 1.91 and the p value of paired t-test was 0.24, therefore there was no prove of the clinical result difference using MSTS before and after the revision surgery. DISCUSSION The acute radical debridement and lavage is preferred, if the surgery can be done up to three weeks after the first clinical signs of infection under the condition of good retention of the implant. In case of extensive infectious damage, when abscess, fistula and loosening of the implant are present and when the patient has a good oncological prognosis, we prefer a twostage revision with a cement spacer stabilized by an external fixator. In patients with mitigated infection or uncertain oncological prognosis we prefer a two-stage revision with the combination of a cement spacer and intramedullary nail fixation. CONCLUSIONS The study presents the results of operative treatment of periprosthetic infection of megaprosthesis and the modification of the two-stage replantation of infected MP with the use of external fixation for stabilisation of a non-articulated cement spacer allowing the patient to remain active during the time before the second stage. Key words: periprosthetic infection, megaprosthesis, bone tumour, external fixator, two-stage revision.

[Salmonella osteomyelitis - a rare differential diagnosis of bone tumors]. / Salmonellenosteomyelitis ­ eine seltene Differenzialdiagnose eines Knochentumors.

This case describes a rare salmonella infection suspected to be an osseous lymphoma. A 27-year-old female presented herself with painful swelling of her knee, with prednisolone-treated Crohn's disease as her only pre-existing condition. Salmonella species group C were detected in the osseous material derived from an extraction. The disease was treated with intravenous ceftriaxone, oral cotrimoxazole as well as multiple debridements. The working diagnosis should thus always be questioned and bone pain in patients who are immunosuppressed should be further investigated.

Tumor-targeting Salmonella typhimurium A1-R regresses an osteosarcoma in a patient-derived xenograft model resistant to a molecular-targeting drug.

Osteosarcoma occurs mostly in children and young adults, who are treated with multiple agents in combination with limb-salvage surgery. However, the overall 5-year survival rate for patients with recurrent or metastatic osteosarcoma is 20-30% which has not improved significantly over 30 years. Refractory patients would benefit from precise individualized therapy. We report here that a patient-derived osteosarcoma growing in a subcutaneous nude-mouse model was regressed by tumor-targeting Salmonella typhimurium A1-R (S. typhimurium A1-R, p<0.001 compared to untreated control). The osteosarcoma was only partially sensitive to the molecular-targeting drug sorafenib, which did not arrest its growth. S. typhimurium A1-R was significantly more effective than sorafenib (P <0.001). S. typhimurium grew in the treated tumors and caused extensive necrosis of the tumor tissue. These data show that S. typhimurium A1-R is powerful therapy for an osteosarcoma patient-derived xenograft model.

A novel co-culture model of murine K12 osteosarcoma cells and S. aureus on common orthopedic implant materials: 'the race to the surface' studied in vitro.

Infection is a major cause of orthopedic implant failure. There are few studies assessing both tissue cell and bacterial adherence on common orthopedic implant materials in a co-culture environment. An in vitro co-culture model was created using K12 osteosarcoma cells and Staphylococcus aureus in a medium incubated over metal disks for 48 h. The results showed that, in the presence of S. aureus, there were fewer osteosarcoma cells attached to the disks for all substrata tested. There were significantly more osteosarcoma cells adhering to the cobalt chrome than the stainless steel and titanium disks. Overall, in the presence of osteosarcoma cells, there were more bacteria adhering to the disks for all the substrata tested, with significantly more bacteria adhering to the stainless steel disks compared to cobalt chrome and titanium disks. Scanning electron microscopy verified that osteosarcoma cells and bacteria were adherent to the metal disks after incubation for 48 h. Furthermore, the observation that more bacteria were in the co-culture than in the control sample suggests that the osteosarcoma cells serve as a nutrient source for the bacteria. Future models assessing the interaction of osteogenic cells with bacteria on a substratum would be improved if the model accounted for the role of the immune system in secondary bone healing.

Tumor-targeting Salmonella typhimurium A1-R inhibits human prostate cancer experimental bone metastasis in mouse models.

Bone metastasis is a frequent occurrence in prostate cancer patients and often is lethal. Zoledronic acid (ZOL) is often used for bone metastasis with limited efficacy. More effective models and treatment methods are required to improve the outcome of prostate cancer patients. In the present study, the effects of tumor-targeting Salmonella typhimurium A1-R were analyzed in vitro and in vivo on prostate cancer cells and experimental bone metastasis. Both ZOL and S. typhimurium A1-R inhibited the growth of PC-3 cells expressing red fluorescent protien in vitro. To investigate the efficacy of S. typhimurium A1-R on prostate cancer experimental bone metastasis, we established models of both early and advanced stage bone metastasis. The mice were treated with ZOL, S. typhimurium A1-R, and combination therapy of both ZOL and S. typhimurium A1-R. ZOL and S. typhimurium A1-R inhibited the growth of solitary bone metastases. S. typhimurium A1-R treatment significantly decreased bone metastasis and delayed the appearance of PC-3 bone metastases of multiple mouse models. Additionally, S. typhimurium A1-R treatment significantly improved the overall survival of the mice with multiple bone metastases. The results of the present study indicate that S. typhimurium A1-R is useful to prevent and inhibit prostate cancer bone metastasis and has potential for future clinical use in the adjuvant setting.

Blastomycosis of bone: a clinicopathologic study.

OBJECTIVES: Blastomycosis osteomyelitis is a well-known but infrequently encountered complication of infection with the dimorphic mold, Blastomyces dermatitidis. Oftentimes, the diagnosis is unsuspected, resulting in a delay in making the diagnosis. The role of intraoperative consultation in making a rapid diagnosis has not been discussed previously. METHODS: Retrospective chart review of clinicopathologic information was conducted from all cases of blastomycosis osteomyelitis and arthritis diagnosed at Rush University Medical Center between 2000 and 2010. RESULTS: Fourteen cases of blastomycosis osteomyelitis and/or arthritis were identified, 12 of which clinically and radiologically presented as a bone tumor. The disease most commonly affected the lower extremities, particularly around the knee joint. Septic arthritis generally occurred secondary to osteomyelitis of the adjacent bone. Frozen section was performed in 10 cases, all of which were correctly diagnosed as granulomatous osteomyelitis. Two cases were culture negative, one of which showed many budding yeast forms typical of B dermatitidis on histology. CONCLUSION: Blastomycosis osteomyelitis should be considered in the differential diagnosis of bone tumor, particularly when there is history of residence or travel in endemic areas. This disease can be correctly identified at frozen section, thus offering rapid diagnosis. There is an excellent correlation between morphologic and microbiologic studies.

Tumor-targeting Salmonella typhimurium A1-R prevents experimental human breast cancer bone metastasis in nude mice.

Bone metastasis is a lethal and morbid late stage of breast cancer that is currently treatment resistant. More effective mouse models and treatment are necessary. High bone-metastatic variants of human breast cancer cells were selected in nude mice by cardiac injection. After cardiac injection of a high bone-metastatic variant of breast cancer, all untreated mice had bone metastases compared to only 20% with parental cells. Treatment with tumor-targeting Salmonella typhimurium A1-R completely prevented the appearance of bone metastasis of the high metastatic variant in nude mice (P < 0.001). After injection of the highly bone-metastatic breast cancer variant to the tibia of nude mice, S. typhimurium A1-R treatment significantly reduced tumor growth in the bone (P < 0.001). These data indicated that S. typhimurium A1-R is useful to prevent and inhibit breast cancer bone metastasis and should be of future clinical use for breast cancer in the adjuvant setting.

Osteomyelitis of the femur mimicking bone tumors: a review of 10 cases.

BACKGROUND: The clinical symptoms and radiographic appearance of osteomyelitis can mimic those of bone tumors. METHODS: We reviewed 10 patients with osteomyelitis of the femur who were initially diagnosed as having bone tumors and were subsequently transferred to our institution. RESULTS: Nocturnal pain of moderate intensity occurred in seven patients, and all 10 patients had elevated C-reactive protein levels. The radiographic findings included the following: a permeative, moth-eaten osteolytic lesion in six patients, an osteolytic lesion with sclerotic borders in three patients, and cortical destruction with pathological fracture in one patient. Magnetic resonance imaging was performed for eight patients, and only one had a positive penumbra sign. All patients underwent a surgical biopsy to confirm the final diagnosis for histological analysis and cultures. Klebsiella pneumoniae was detected in six patients and Staphylococcus aureus, the most common organism in osteomyelitis, was detected in three. Recurrence of infection occurred in five patients following debridement surgery; of these three had a Klebsiella pneumoniae infection. All patients received antibiotic treatment for an average of 20.4 weeks (range, 4 to 44) and surgical treatment an average of 1.8 times (range, 1 to 4). At the final follow-up, all patients were fully recovered with no signs of infection. CONCLUSIONS: When used in combination, clinical examinations, laboratory data, and radiographic findings can reliably distinguishing osteomyelitis from bone tumors.

Salmonella osteomyelitis in an immunocompromized patient presenting as a primary lymphoma of the bone.

During the past few decades, an increasing number of immunosuppressive drugs have been developed to treat autoimmune and rheumatic diseases, as well as post-transplant patients. In parallel, the incidence of immunocompromized patients in the general population has risen, for example, patients who are HIV positive, undergoing hemodialysis or suffering from diabetes mellitus. In such predisposed patients, infections with organisms of even reduced invasive potential can result in atypical invasive manifestations. In industrialized countries, an increase in the number of human non-typhoid Salmonella infections was observed in the 1980-1990s [Shimoni Z, Pitlik S, Leibovici L, Samra Z, Konigsberger H, Drucker M, et al. Nontyphoid Salmonella bacteremia: age-related differences in clinical presentation, bacteriology, and outcome. Clin Infect Dis 1999;28:822-7]. Beyond the main clinical manifestation of gastroenteritis, there is an increasing prevalence of extra-intestinal infections by this pathogen. We report a patient with acute osteomyelitis due to Salmonella typhimurium without any previous signs of gastroenteritis.

High hydrostatic pressure, a novel approach in orthopedic surgical oncology to disinfect bone, tendons and cartilage.

High hydrostatic pressure (HHP) is widely used in the food processing industry, for example to inactivate vegetative microorganisms in meat products, milk and juice, thereby avoiding the addition of any chemical preservatives. Besides this, HHP is also an attractive novel approach to effectively kill vegetative microorganisms or tumor cells in bone, cartilage and tendon ex vivo while leaving the tissues' mechanical properties unimpaired, thus allowing reimplantation of the resected tissue explants. In contrast, sterilization by gamma irradiation and thermal or chemical inactivation of potentially infected autografts, allografts and other biomaterials considered for tissue regeneration and reconstruction is often associated with deterioration of the mechanical, physical and biological properties of the implant. HHP technology is now in preclinical testing with the aim of disinfecting/devitalizing grafts in order to inactivate both vegetative microorganisms and tumor cells in resected bone tissue segments, eventually allowing reimplantation of resected bone segments initially afflicted with osteomyelitis or tumors. The technical advantages, state-of-the-art, and potential application of HHP in orthopedic surgery are reviewed.

Infections in children and young adults with bone malignancies undergoing limb-sparing surgery.

BACKGROUND: The epidemiology, risk factors, and efficacy of therapy for infections complicating limb-sparing surgery (LSS) are not understood completely. METHODS: The authors conducted a retrospective review of children and adolescents with bone malignancies who underwent LSS. RESULTS: One hundred three patients underwent 104 LSS procedures. Patients experienced a median of 4 infections (range, 0-13 infections), including focal bacterial infections in 67% of patients and bacteremia in 21% of patients. Infections at the LSS site occurred in 26% of patients, and 21% of patients developed orthopedic device infections (ODIs). Compared with patients without ODIs, patients who developed ODIs were more likely to be African American and to have wound infections, and they were less likely to have tumors of the femur than the tibia. In a multivariate analysis, only African-American race and local infection at the LSS site retained a significant association with ODIs. Among survivors, patients who developed ODIs were more likely to undergo amputation (odds ratio [OR], 24.0; 95% confidence interval [95%CI], 5.1-114.0; P < 0.001) and were less likely to have good functional outcomes (OR, 0.02; 95%CI, 0.002-0.15; P < 0.001) compared with patients who did not have an ODI. Overall, only 1 of 22 patients with an ODI was treated successfully without removal of the orthopedic device or amputation. CONCLUSIONS: Current treatment for bone malignancies is complicated by an unexpectedly high incidence of infection. ODI was the most common reason for amputation and poor functional outcomes. The identification of risk factors for ODI may allow modifications of therapy that reduce the incidence and severity of infection, but prevention of all ODIs will require novel strategies.

The effect of GM-CSF and G-CSF on the growth of human osteosarcoma cells in vitro and in vivo.

The human osteosarcoma cell line, MG63, responds both to GM-CSF and to G-CSF in vitro. To assess the significance of these observations to tumor growth in vivo, MG63 cells were engineered by retroviral infection to produce human GM-CSF or G-CSF. These retrovirally infected cells become autostimulatory as measured by increased [3H]-thymidine incorporation (3- to 7-fold) and anchorage-independent colony formation (7- to 10-fold) as compared with uninfected MG63 cells or cells infected with control (neor) retrovirus. The increased proliferation induced by exogenous GM-CSF or G-CSF on uninfected MG63 cells in both assays could be completely inhibited by anti-GM-CSF or anti-G-CSF antibodies, while the same antibodies only partially abrogated proliferation by the growth-factor-producing cells. None of 34 nude or SCID mice developed tumors when injected s.c. with uninfected or neor-virus-infected cells. In contrast, all 30 mice injected with GM-CSF- or G-CSF-producing MG63 cells developed tumors which were G418-resistant and factor-producing. Tumor cell DNA showed a polyclonal retroviral integration pattern indistinguishable from that in the DNA of cells injected into mice. Tumors that formed following injection of a mixture of G418-resistant, GM-CSF-producing cells and cells infected with virus containing only the hygror gene contained hygromycin-resistant cells in the same proportion as was present in the original cell mixture. These data indicate that GM-CSF and G-CSF can support the growth of an osteosarcoma cell line both in vitro and in vivo whether the factor is supplied by autocrine production or from exogenous sources.

Confounded carcinogenicity study of sodium fluoride in CD-1 mice.

To determine its carcinogenic potential, sodium fluoride (NaF) was fed to CD-1 mice for up to 97 weeks. Mice given NaF at a dose of 4, 10, or 25 mg/kg of body weight per day added to a low-fluoride diet were compared to controls given either an unsupplemented low-fluoride diet or laboratory chow. Nonneoplastic changes consistent with those previously recognized from fluoride toxicity were observed in teeth, bones, and joints. Unexpectedly, osteomas occurred in all groups. The incidence of osteomas was similar in groups given the low-fluoride control diet, laboratory chow, or NaF doses of 4 or 10 mg/kg per day. The incidence of osteomas in these groups was increased over that historically experienced at the laboratory and reported in the literature for CD-1 mice. The incidence of osteomas in the mice given 25 mg NaF/kg per day added to a low-fluoride diet was increased over that in the other groups. Osteomas were first observed at Week 55. No malignant bone tumors were observed during the course of the study. The locations, multiplicity, and morphologic features of the osteomas in all groups were similar to those associated with virus-induced bone tumors. Electron microscopic examination revealed abundant retrovirus particles in all osteomas examined from control and test mice. It was concluded that the study was confounded by a retrovirus which contributed to the induction of the osteomas. Because the study was confounded, it cannot be considered a valid bioassay to be used for risk assessment.

Myeloid leukaemogenicity and transmission of the HPRS-103 strain of avian leukosis virus.

The HPRS-103 strain of avian leukosis virus (ALV) was isolated recently from meat-type chickens and represents a new envelope subgroup. Its oncogenicity has been studied in three meat-type and five Leghorn strains of chickens. In the meat-type strains, the virus, following embryonal inoculation, induced an overall incidence of 27% myelocytic myeloid leukosis (myelocytomatosis) and 12% renal adenomas, with long median latent periods. Amongst the Leghorn lines, these tumors occurred with similar incidence in line 0, but with lower or zero incidences in the other lines. A variety of other tumours occurred with low incidence. Embryonal infection resulted in a permanently tolerant viraemic state with shedding of ALV group specific (gs)-antigen to egg albumen; contact infection resulted mainly in the development of non-shedder birds with serum virus-neutralising antibodies. Contact infection in a meat-type line was associated with the development of transient or permanent viraemia in some birds, and a low tumour incidence. A viraemic phase was not detected following contact infection in a Leghorn line and no tumours developed. The long latent period between embryo infection and tumour mortality, apparently differing from the consequences of infection with acutely transforming ALVs, and the inability of HPRS-103 ALV to transform cultured bone marrow cells, suggests that this virus may lack a viral oncogene and exert its oncogenic properties by some other mechanism such as promoter insertion activation of a cellular oncogene.

Regulation of an H-ras-related transcript by parathyroid hormone in rat osteosarcoma cells.

The rat osteosarcoma cell line UMR 106-01 is a commonly used model system for the study of osteoblast function. However, it also expresses a phenotype characteristic of transformed cells. To test whether the latter could be accounted for by aberrant oncogene expression, we probed Northern blots of UMR and other osteoblastic cells with a panel of oncogene probes. These blots, when probed with a cDNA specific for v-H-ras, revealed a 7.0-kilobase (kb) H-ras-related transcript (designated HRRT) in UMR 106-01 cells that was not expressed in other osteoblastic cells. Osteoblast-enriched calvarial cells expressed the typical 1.1-kb H-ras mRNA, which was absent in UMR cells. Additionally, Western blots of lysates of UMR cells documented the presence of three proteins immunologically related to H-rasp21. To determine whether HRRT represented a recombinant retrovirus product, Northern blots were probed with a cDNA specific for the highly conserved gag-pol region of Moloney murine leukemia virus. These blots showed parallel cross-reactivity with an apparently identical transcript of 7.0 kb. The 7.0-kb transcripts detected by both v-H-ras and gag-pol probes declined to the same extent after treatment with concentrations of PTH known to inhibit proliferation of these cells. PTH regulated the abundance of HRRT in a time- and dose-dependent manner, with greatest repression of the transcript after 8 h of treatment with 10(-8) M PTH. The decrease in HRRT could not be completely accounted for by changes in transcriptional activity, as determined by nuclear run-on assays.(ABSTRACT TRUNCATED AT 250 WORDS)

Retroviruses that express different ras mutants cause different types of tumors in chickens.

We have used replication-competent retroviral vectors to express avian and murine ras genes in cultured chick embryo fibroblasts (CEF) and in chickens. Since the viral vectors are identical, it is possible to compare the oncogenic potential of the ras genes directly. The normal (12 gly) form of chicken c-Ha-ras is not oncogenic in vivo, nor does high-level expression transform CEF. Expression of murine v-ras or modified forms of chicken c-Ha-ras with either lysine or glutamine at position 12 transforms CEF and causes tumors in birds. However, the oncogenic potential of the transforming ras genes is different; the viruses that express the genes with lysine and glutamine at position 12 cause a distinct spectrum of tumors.