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Ultrasonography after hip arthroplasty.

Ultrasonography was performed in 55 patients who had total Charnley hip arthroplasties. Effusions were identified in 19 patients and confirmed in all but 3 by arthrocentesis or at surgery. Aspirations were performed in 5 and demonstrated infection in 2. It is concluded that ultrasound is a valuable noninvasive method for assessing painful hip arthroplasty. It can demonstrate the presence of effusion, which should be aspirated to exclude infection.

Aged↗

Immunoscintigraphy with antigranulocyte monoclonal antibodies for the diagnosis of septic loosening of hip prostheses.

To determine the value of immunoscintigraphy (IS) with antigranulocyte monoclonal antibodies (Mab) in the diagnosis of subacute or chronic infection of hip prostheses, we prospectively studied 57 patients (23 women and 34 men; age 29-92 years, mean 72.7 years) sent to our institution in the past 6 years for clinical suspicion of septic loosening of a hip prosthesis. Nineteen patients had bilateral prostheses and one of them was studied twice. A total of 78 prostheses were examined. All patients had three-phase bone scans followed by IS with technetium-99m antigranulocyte Mab BW 250/183. Intervals between bone scans and IS varied from 2 days to 4 weeks. Final diagnosis was assessed by culture in 48 cases (articular puncture or intraoperative sampling) and by clinical follow-up of at least 8 months in 30 cases. Twelve prostheses were considered septic and 66 non-septic. The overall sensitivity and specificity were 92% and 64% respectively for bone scans, 67% and 75% for IS and 67% and 84% for both modalities together. In three cases, IS was doubtful and the final clinical diagnosis was negative for infection. False-positive results were observed in the presence of massive loosening of the prosthesis or in association with metaplastic peri-articular bone formation. In three of the four false-negative results, infection was proven only after enrichment of the culture, and the bacterium was Staphylococcus epidermidis. In 12/33 (36%) positive bone scans IS allowed the diagnosis of infection to be excluded. Overall accuracy of both modalities together was 81% and the negative predictive value was 93%, which compares favourably with the results reported for other non-invasive methods.

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Conservative management of a methicillin-resistant Staphylococcus aureus (MRSA)-infected aortobifemoral graft: report of a case.

A 63-year-old man was referred to our department for treatment of intermittent claudication in the right lower limb. The preoperative angiogram showed severe stenosis extending from the terminal aorta to the bilateral common femoral arteries, with occlusion of the right superficial femoral artery and the left popliteal artery. He underwent aortobifemoral bypass with thromboendarterectomy of the left common femoral artery, and right graft-popliteal artery bypass. The patient had an uneventful postoperative course; however, 14 days after the operation, a pulsatile mass suddenly appeared in the left groin. Emergency surgery revealed disruption of the left distal anastomosis of the aortobifemoral bypass and therefore, revision, in the form of graft-profunda femoris artery interposition with graft-superficial femoral artery bypass, was performed. Microscopic examination showed colonies of bacteria in the host artery adventitia adjacent to the anastomosis. Culture of the discharge from the right groin operative scar revealed methicillin-resistant Staphylococcus aureus (MRSA). The discharge resolved following the intravenous administration of vancomycin and the local application of vancomycin ointment. There were no operative complications other than the MRSA infection, and the patient was discharged 20 days after revision surgery. In the 14 months since the revision, all grafts have remained patent and there have been no further symptoms of graft infection.

Anti-Bacterial Agents↗

[Inflammatory pseudotumor of the ileopsoas muscle with femoral paralysis caused by massive metal abrasion of a hip endoprosthesis].

Case report of a 62-year-old patient with a presumed loosening of a hip endoprosthesis after 10 years and a planned replacement. In addition, the patient suffered pain in the thigh and had paresis of the femoral nerve. A CAT-Scan substantiated the diagnosis either of a suppurating or a neoplastic tumour in the left iliac foss. The wide excision revealed a rare inflammatory tumour in the left ileopsoas muscle due to the excessive abrasion of the metal hip endoprosthesis.

Diagnosis, Differential↗

[Covering extensive soft tissue defects in infected knee endoprostheses by gastrocnemius flap].

Total knee arthroplasty has become a routine procedure in surgery. Deep infections have an incidence of 2-5%. Major risk factors are large prostheses, rheumatoid arthritis, diabetes mellitus and postoperative wound-healing complications. In large soft-tissue defects with skin necrosis, local wound care shows poor results, especially if loosening of the prosthesis and necrosis of the patellar ligament are evident. In these cases, no standard surgical therapy has been developed yet. Thus, we consider meticulous débridement with synovialectomy to be mandatory. Exchange of the prosthesis may be necessary. Soft-tissue coverage ought to be performed with a gastrocnemius muscle flap covered with a split-thickness skin graft. In the last three years, 11 patients with large soft-tissue defects and necrosis of the ligament were treated according to this concept. In all cases the muscle flap healed primarily and soft tissue coverage was excellent. Two patients who underwent single-stage removal and reimplantation of the prosthesis showed reinfections of the prosthesis. Reconstruction of the ligament was performed with the flap tendon. The patients with two-stage removal and reimplantation of the prosthesis and those who retained their implants had a good functional outcome. The gastrocnemius muscle flap provides easy and reliable soft-tissue reconstruction in large defects. In our patients a two-stage operation for reimplantation of the prosthesis was superior to a single-stage procedure. The reconstructed ligament should be reinforced with autologous material to prevent a secondary rupture. Early reconstruction with sufficient soft-tissue coverage and reconstruction of the ligament offers the patient the best chances of obtaining a good functional result and prevents arthrodesis or amputation. In addition, reconstructive surgery reduces the length of hospital stay and costs.

Aged↗

[Current developments in cochlear implantation].

Over the last 20 years, cochlear implantation has become a well accepted treatment in patients suffering from hearing loss or congenital deafness. Results have been impressive,and indications for a cochlear implant have been extended continuously. Thanks to a sophisticated diagnostic procedure, optimization of the surgical technique, and the progression of interdisciplinary cooperation in the field of rehabilitation, the acceptance of cochlear implantation is growing significantly. The manufacturers of the devices are making great efforts to miniaturize the external components of the system, and new developments in electrode arrays, combined with new speech coding strategies, result in better speech understanding. The new developments in electrode design, however, are not necessarily improvements over recent years. Nevertheless, a very well functioning network of physicians, scientists, and manufacturers has acted and reacted in an outstanding manner to identify possible causes of post-implantation meningitis, have taken immediate counter measures and presented possibilities of prevention.

Cochlear Implantation↗

[Perforation of the esophagus with a mediastinal abscess].

INTRODUCTION: Surgical voice rehabilitation after total laryngectomy is still only a partially solved problem. Because of easy handling and rare complications, the Provox voice prosthesis has become common in voice rehabilitation. CASE REPORT: The 69 year old patient underwent laryngectomy, selective bilateral neck dissection and the implantation of a Provox voice prosthesis because of a glottic squamous cell carcinoma (pT(4), pN(0), M(0)). Postoperative healing ensued without any complications. During adjuvant radiochemotherapy, the patient developed distinctive cervical edema which led to a tilting of the Provox prosthesis. Due to a perforation of the posterior esophageal wall, the patient developed a pronounced mediastinal abscess which was relieved through a transcervical mediastinotomy. Antibiotic therapy led to a partial remission of the symptoms. CONCLUSION: Severe complications may not only occur during the early phase of surgical voice rehabilitation, but also at a much later stage, after completion of the healing process. A voice prosthesis which is too long or generates pressure from a radiogenic edema, cannula and finger pressure used to close the tracheostoma is transmitted through the prosthesis and may lead to a perforation of the posterior esophageal wall. In particular, when the tissue is injured during the course of radiotherapy, this type of complication should be taken into consideration.

Abscess↗

[Why do osteosyntheses fail? The problem with biomechanics and biology].

Avoidance of complications in the course of fracture treatment is of essential importance not only for patients but increasingly from an economic point of view. In the past 15 years emphasis has been placed on the development and fine-tuning of minimally invasive reduction techniques with suitable implants. The main objectives were avoidance of surgical site infection and uneventful fracture healing. This facilitated the solving of long-standing problems but created new sources of error. Minimally invasive, dynamic forms of osteosynthesis were found to fail with extensive open reduction or neglect of biomechanics. Additionally, it appeared that some traditional techniques and basic rules of operative fracture treatment fell into oblivion. The majority of complications are determined already preoperatively by the choice of treatment or implant. After exact analysis of the biomechanics and biological etiology, nonunion is dealt with by an imperative increase in mechanical stability. Additional procedures, i.e., bone graft or debridement, are incorporated into the therapeutic regime. Increasing mechanical stability should be attempted with a minimum of added trauma to avoid local biological impairment. Further improvement of outcome depends on innovative and adapted teaching concepts. Training exclusively with one implant, even under the guidance of the producing company, is insufficient to grasp the various fundamentals of operative fracture treatment indispensable for a successful day-to-day routine.

Biomechanical Phenomena↗

[Diagnostic imaging in hip prostheses].

Hip arthroplasty has become a common and still increasing procedure for the treatment of osteoarthritis, advanced head necrosis, post-inflammatory arthritis or rheumatoid arthritis. Radiography is the most important imaging modality for monitoring the normal, asymptomatic hip arthroplasty. Radiographs are obtained at the end of a surgical treatment, to exclude complications like fracture or component misplacement. In the follow-up radiographs are used for the diagnosis of loosening and infection of the hip arthroplasty as well as soft tissue ossification. Together with the history and clinical information, the analysis of morphological findings allows to find the grade of loosening. MRI has been advocated in the diagnosis of infection, in particular in the localisation of soft tissue involvement. Imaging, especially by radiographs, is used for the evaluation of the normal and complicated follow-up of hip arthroplasty.

Aged↗

[Septic loosening of a Wagner revision stem provoked by Mycobacterium tuberculosis].

Only a few cases of specific tuberculous infections of total hip arthroplasties have been published. We report the case of a 66-year-old male patient who received a cementless total hip arthroplasty due to osteoarthritis of the left hip in 1990. Four years later, revision arthroplasty with a Wagner revision stem was performed because of aseptic loosening. In 1995 revision of a loosened acetabular cup was necessary. In 1996 we saw the patient for the first time in our outpatient unit. He complained of increasing pain in the region of the left hip. X-rays showed loosening of the Wagner stem. Aspiration of the synovial fluid of the left hip revealed an infection with mycobacterium tuberculosis (radioimmunoassay). There were no signs of tuberculous infection in the patient's history. Treatment consisted of removal of the prosthesis followed by antituberculosis chemotherapy for 12 months with rifampicin, ethambutol, isoniazid, and pyrazinamide. In April 2001 revision of the left hip joint and implantation of a MRP titanium revision stem and reconstruction of the acetabulum with an acetabular reconstruction ring was done. Until today the patient exhibits no signs of recurrence of the tuberculous infection.

Acetabulum↗

[Bilateral localized osteolysis after cemented total hip replacement].

The incidence of focal progressive osteolysis after THR is about 8% and 56%. Most often osteolysis is correlated with macrophage-induced osteoclastic bone resorption as a sequel of inflammatory reaction to wear particles. Recently these findings were published in respect to allergic reactions to implants, their alloying constituents, or bone cement. We report about a patient who developed bilateral localized osteolysis just below the cement mantle 5 years after cemented THR with a Müller straight stem. In the middle of the osteolysis small fragments of bone cement could be detected. Epicutaneous testing showed no reaction against cobalt, chromium, or nickel. Further epicutaneous testing in respect to ingredients of the bone cement were refused by the patient. Histological examination revealed a histiocytic reaction to wear particles and surrounding giant cells. To our knowledge, this is the first case of bilateral localized osteolysis after cemented total hip replacement. Taking all results of the current case into account, it is still unclear if a lymphocytic allergic contact reaction did contribute to the sequel of this case. Reports of immunologically induced incompatibility to components of bone cement, the development of extended testing procedures, and further scientific research should contribute to optimizing the care of patients.

Bone Cements↗

[Inflammatory reactions in the wear particle induced and infectious periprosthetic membrane of loosened hip- and knee endoprostheses: pathogenetic relevance of differentially expressed genes cd9, cd11b, cd18, cd52 and pdgfrbeta].

BACKGROUND: A previous cDNA-microarray analysis described constantly differentially expressed genes in wear particle induced and infectious SLIM (synovial-like interface membrane). This study aims to validate the cDNA microarray data in order to approve differences of the gene expression profiles of RNA and proteins. METHODS: Tissue from 16 wear particle induced and 20 infectious periprosthetic membranes were analyzed by RT-PCR and immunohistology with regard to the expression of inflammatoric associated genes. RESULTS: RT-PCR showed the genes cd9, cd11b, cd18, cd52 as well as pdgfrbeta in interface membranes. In the wear particle induced membrane the immunohistochemical analysis showed a significantly weaker gene expression of PDGFRbeta, whereas the differential overexpression of CD9, CD11b and CD52 was confirmed. For CD18, there was no difference in expression between wear induced and infectious periprosthetic tissue. CONCLUSION: Different pathomechanisms, which are reflected by different gene expression profiles, might produce different types of periprosthetic membranes. By RT-PCR and immunohistochemical analysis the micro array data of the genes cd9, cd11b, cd52 and pdgfrbeta could be validated. Identifying the gene products of cd9, cd11b and cd52 in blood or tissue may help to differentiate between wear induced and infectious loosening.

Adult↗

[The infected implant. Part 1: bacteriology].

Periprosthetic infection is a significant complication in joint replacement surgery and develops in 0.5-2% of cases. Staphylococcus aureus and commensal microorganisms of the skin, especially coagulase-negative staphylococci, as well as a broad spectrum of other potential pathogens typically already colonize the surface of the foreign body at the time of implantation. Specific mechanisms such as bacterial adhesion to host factors absorbed in the material, biofilm formation, and a metabolic adaptation of adherent microorganisms play a particularly important role in the pathogenesis and course of the disease. Microbiological diagnosis requires to some extent complex culture procedures of puncture specimens or tissue removed during surgery; this can be supplemented by modern molecular testing. Antimicrobial treatment must be conceived as a synopsis of clinical picture, confirmed pathogen, and the intended surgical procedure on an individual basis and is routinely administered as combination therapy for several weeks, sometimes also as sequential therapy. Validated preventive measures in joint replacement surgery include mandatory perioperative antibiotic prophylaxis and other additional measures.

Anti-Bacterial Agents↗

[Diagnosis of septic loosening of hip prosthesis with LeukoScan. SPECT scan with 99mTc-labeled monoclonal antibodies].

Diagnosis of septic loosening of hip endoprosthesis with antigranulocyte scintigraphy (AGS) was analysed. Twenty-one hip prostheses were studied using laboratory tests and, in cases of elevated values, three-phase bone scan (BS) and AGS. Elective SPECT/CT scans were performed. Histologic and microbiologic exams verified the diagnosis. The AGS analysis revealed sensitivity, specificity and accuracy of value 1, while positive and negative predictive values were also 1. BS showed sensitivity of 1 and specificity of 0.33. In three cases, SPECT/CT scans corroborated the AGS interpretation. This diagnostic algorithm proved effective in the detection of septic loosening of hip prostheses. AGS can be avoided without risk of infection being overlooked.

Aged↗

[Revision of tumour endoprostheses around the knee joint. Review and own results].

Revision of tumour endoprostheses around the knee joint is mainly caused by aseptic loosening and deep infection. Mechanical complications have been significantly reduced by improvements in prosthetic design. The rate of aseptic loosening after distal femur or proximal tibia replacement ranges from 10% to 45% depending on the time of follow-up and prosthetic design; the success rate after revision averages 75% at midterm follow-up. The rate of infection reported in the literature varies between 2.9% and 12%. One stage revision may be considered after acute infection without signs of loosening, after which a success rate of 77.8% can be expected. Two stage revision is mainly indicated in multi-resistant microorganisms as well as septic loosening, with a success rate of 75% after 5 years. Deep infection represents the most serious complication in long-term follow-up, often leading to amputation due to soft tissue problems after tumour resection. The authors were able to confirm the minimal decrease in MSTS score despite the large number of operations (15 patients: nine females, six males; median MSTS score 84%; mean 81%).

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