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At least 1,063 records · Page 59Linked to original sources
PubMed1992

Iliopsoas bursal distension caused by acetabular loosening after total hip arthroplasty. A rare complication of total hip arthroplasty.

In a 58-year-old woman, a cystic mass at the ileocecal region communicated with the loosened hip prosthesis 20 years after total hip arthroplasty (THA). The preoperative arthrogram of the hip and the intraoperative cystogram suggested a one-way communication from the hip to the cystic mass. The mass was diagnosed as an iliopsoas bursitis distended by the influx of the synovial fluid from the loosened THA.

Abdominal Neoplasms↗
PubMed2000

Development of a computer model to predict pressure generation around hip replacement stems.

Cemented fixation of hip replacements is the elective choice of many orthopaedic surgeons. The cement is an acrylic polymer which grouts the prostheses into the medullary cavity of the femur. Cement pressure is accepted as a significant parameter in determining the strength of cement/bone interfaces and hence preventing loosening of the prostheses. The aim of this work was to allow optimal design of the intramedullary stem of a hip prosthesis through knowledge of the flow characteristics of curing bone cement which can be used to predict pressures achieved during insertion of the femoral stem. The viscosity of the cement is a vital property determining the cement flow and hence cement interdigitation into bone. The apparent viscosities, nu(a), of three commercial bone cements were determined with respect to time by extrusion of the curing cement through a parallel die of known geometry under selected pressures. Theoretical models were developed and implemented in a computer program to describe cement flow in three models each of increasing complexity: (a) a simple parallel cylinder, (b) a tapered conical mandrel and (c) an actual femoral prosthesis, the latter models being complicated by extensional effects as annular areas increase. Predicted pressures were close to those measured experimentally, maximum pressures being in the range 10-160 kPa which may be compared with a threshold of 76 kPa proposed for effective interdigitation with cancellous bone. The theoretical model allows the prosthesis/bone geometry of an individual patient to be evaluated in terms of probable pressure distributions in the medullary cavity during cemented fixation and can guide stem design with reference to preparation of the medullary canal. It is proposed that these models may assist retrospective studies of failed components and contribute to implant selection, or to making informed selection from options in custom hip prosthesis designs to achieve optimum cement pressurization.

Bone Cements↗
PubMed2003

Image reconstruction and the effect on dose calculation for hip prostheses.

High atomic number inserts, such as hip prostheses and dental fillings, cause streak artifacts on computed tomography (CT) images when filtered back-projection (FBP) methods are used. These streak artifacts severely degrade our ability to differentiate the tumor volume. Also, incorrect Hounsfield numbers yield incorrect electron density information that may lead to erroneous dose calculations, and, as a result, compromise clinical outcomes. The aim of this research was to evaluate the dosimetric consequences of artifacts during radiotherapy planning of a prostate patient containing a hip prosthesis. The CT numbers corresponding to an iron prosthesis were inserted into the right femoral head of an existing CT image set. This artifact-free image was used as the standard image set. CT projections through the image set formed the sinogram, from which filtered back projection and iterative deblurring methods were used to create reconstructed image sets. These reconstructed image sets contained artifacts. Prostate treatment plans were then calculated using a Monte Carlo system for the standard and reconstructed CT image sets. Close to the prosthesis, the CT numbers between the reconstructed and standard image sets differed substantially. However, because the CT number differences covered only a small area, the dose distributions on the reconstructed and standard image sets were not significantly different. The dose-volume histograms for the prostate, rectum, and bladder were virtually identical. Our results indicate that even though CT image artifacts restrict our ability to differentiate tumors and critical structures, the dose distributions for a prostate plan containing a hip prosthesis, calculated on both artifact-free image sets and image sets containing artifacts, are not significantly different.

Algorithms↗
PubMed2001

The effect of socket design, materials and liner thickness on the wear of the porous coated anatomic total hip replacement.

The wear of joint replacement prostheses represents the greatest challenge to their continued development. Parameters such as polyethylene quality, liner thickness and metal backing have all been implicated as potential detractors in the search for the lowest-wearing socket. This study examined the effect of these parameters through an extensive study of the two versions of the porous coated anatomic (PCA) hip prosthesis (one-piece socket and snaplock socket). For the whole cohort the wear rate was found to be 88 (SE 10) mm3/year and the clinical wear factor was 2.00 (SE 0.28) x 10(-6) mm3/N m. When the two socket types were investigated individually, the wear factors found were 2.39 (SE 0.44) x 10(-6)mm3/N m and 0.99 (SE 0.25) x 10(-6) mm3/N m for the one-piece and snaplock, respectively. This illustrates that the metal backing per se does not predispose these sockets to rapid wear. The good wear performance of the snaplock liner may be attributed to the high quality of the ultra-high molecular weight polyethylene (UHMWPE) used and the shorter implantation period compared to that for the one-piece design. No correlation was found between the thickness of the liner and the clinical wear factor. Within the range of thicknesses tested here, UHMWPE thickness is not an influential parameter for the hip prosthesis and this is confirmed

Arthroplasty, Replacement, Hip↗
PubMed2004

Analysis of elastohydrodynamic lubrication in McKee-Farrar metal-on-metal hip joint replacement.

An elastohydrodynamic lubrication (EHL) analysis was carried out in this study for a typical McKee-Farrar metal-on-metal hip prosthesis under a simple steady state rotation. The finite element method was used initially to investigate the effect of the cement and bone on the predicted contact pressure distribution between the two articulating surfaces under dry conditions, and subsequently to determine the elastic deformation of both the femoral and the acetabular components required for the lubrication analysis. Both Reynolds equation and the elasticity equation were coupled and solved numerically using the finite difference method. Important features in reducing contact stresses and promoting fluid-film lubrication associated with the McKee-Farrar metal-on-metal hip implant were identified as the large femoral head and the thin acetabular cup. For the typical McKee-Farrar metal-on-metal hip prosthesis considered under typical walking conditions, an increase in the femoral head radius from 14 to 17.4 mm (for a fixed radial clearance of 79 microm) was shown to result in a 25 per cent decrease in the maximum dry contact pressure and a 60 per cent increase in the predicted minimum film thickness. Furthermore, the predicted maximum contact pressure considering both the cement and the bone was found to be decreased by about 80 per cent, while the minimum film thickness was predicted to be increased by 50 per cent. Despite a significant increase in the predicted minimum lubricating film thickness due to the large femoral head and the thin acetabular cup, a mixed lubrication regime was predicted for the McKee-Farrar metal-on-metal hip implant under estimated in vivo steady state walking conditions, depending on the surface roughness of the bearing surfaces. This clearly demonstrated the important influences of the material, design and manufacturing parameters on the tribological performance of these hard-on-hard hip prostheses. Furthermore, in the present contact mechanics analysis, the significant increase in the elasticity due to the relatively thin acetabular cup was not found to cause equatorial contact and gripping of the ball.

Acetabulum↗
PubMed1993

Oral rifampin plus ofloxacin for treatment of Staphylococcus-infected orthopedic implants.

We examined the effectiveness and safety of the combination of rifampin plus ofloxacin given orally for treating prosthetic orthopedic implants infected with staphylococci. The prospective cohort study was conducted in a referral public hospital with ambulatory care services between 1985 and 1991. Consecutive patients from whom Staphylococcus organisms susceptible to the study drugs were isolated from their orthopedic implants and who had no contraindication to the treatment were eligible for the study. All patients were treated orally with rifampin, 900 mg/day, plus ofloxacin, 600 mg/day. Patients with hip prosthesis infection were treated for 6 months, with removal of any unstable prostheses after 5 months of treatment; patients with knee prosthesis infection were treated for 9 months, with removal of the prosthesis after 6 months of treatment; and patients with infected bone plates were treated for 6 months, with removal of the plate after 3 months of treatment, if necessary. Monthly clinical evaluations were conducted until the completion of the treatment and follow-up or telephone interviews were conducted at 6, 12, 24, 36, 48, and 60 months thereafter. Treatment failures were documented by clinical evaluation, sampling of the infected site for culture and antibiotic activity measurement, and fistulography, if possible. Cure was defined as the absence of clinical, biological, and radiological evidence of infection 6 months after the completion of treatment, treatment failure was defined as the absence of cure, and relapse was defined as the reappearance of infection caused by the same Staphylococcus isolate that caused the original infection, regardless of the timing of this secondary infection. Among 51 patients included in the study and evaluable for safety, 4 patients had side effects and were not evaluable for treatment effectiveness; the overall success rate was 74% among 47 patients, with a success rate of 81% for the hip prosthesis group, 69% for the knee prosthesis group, and 69% for the osteosynthesis device group. Eight treatment failures were relaxed to the isolation of a resistant bacterium. The combination of rifampin administered orally plus ofloxacin is a suitable alternative to the conventional long-term intravenous therapy for treatment of orthopedic implants infected with staphylococci.

Administration, Oral↗
PubMed1990

Aggressive granulomatous lesions associated with hip arthroplasty. Immunopathological studies.

The local immunopathological response was analyzed in six patients who had a revision of a total hip prosthesis because of an aggressive granulomatous lesion and in six patients who had a revision because of common loosening of the prosthetic stem. All twelve patients had had a total replacement arthroplasty for primary osteoarthrosis. All of the prostheses had been cemented. The aggressive granulomas consisted of well organized connective tissue containing histiocytic-monocytic and fibroblastic reactive zones. The granulomas were highly vascularized, and villous structures were observed at many sites. In contrast, the areas around the loose cemented stems were characterized by dense connective tissue. Immunohistological evaluation revealed that most of the cells in the aggressive granulomatous tissue were multinucleated giant cells and C3bi-receptor and nonspecific esterase-positive monocyte-macrophages. This cytological finding suggests a foreign-body-type reaction, compatible with the rapidly progressive lytic nature of the lesion that was shown radiographically. There was a clear-cut difference between aggressive granulomatosis and the more common lesion accompanying prosthetic loosening--namely, the relative lack of activated fibroblasts in granulomatosis. We suggest that granulomatosis involves an uncoupling of the normal sequence of monocyte-macrophage-mediated clearance of foreign material and tissue debris that is normally followed by fibroblast-mediated synthesis and remodeling of the extracellular matrix. We also suggest that aggressive granulomatosis in association with a cemented hip prosthesis is a distinct entity, not only clinically and radiographically, but also histopathologically.

Aged↗
PubMed2006

Cross-linked N-telopeptide of type I collagen (NTx) in urine as a predictor of periprosthetic osteolysis.

Periprosthetic osteolysis is often nonsymptomatic and hard to visualize by conventional radiography. Cross-linked N-telopeptide of type I collagen (NTx), a marker of osteoclast mediated bone resorption, has been suggested to evaluate local particulate-induced osteolysis in patients operated on with a total hip prosthesis. Urine specimens were sampled after hip joint replacement in 160 patients. NTx was analyzed by a commercially available ELISA kit. Osteolysis was identified in the acetabulum and confirmed at operation. Using analysis of covariance to correct for differences in age, gender, and time after operation, NTx (mean SD) was 36+/-12 BCE/nM creatinine in patients with osteolysis (n=33) and 27+/-13 BCE/nM creatinine in patients without osteolysis (n=127) (p=0.003). Eighteen hips of 38 (47%), demonstrating an annual wear of more than 0.2 mm and an NTx value above 29 BCE/nM creatinine, had been revised due to osteolysis. The osteolysis prevalence in this group was increased 10 times (CI 4-23, p<0.05). Indeed, NTx release and annual wear were both associated with increased prevalence of osteolysis, however, independently of each other. NTx seems a feasible marker of periprosthetic osteolysis. A preoperative baseline NTx level is likely needed for its use as a predictor of periprosthetic osteolysis in individual cases.

Adult↗
PubMed2004

[Surgical treatment of osseous metastases of the pelvis].

Metastases are the most frequent malignant tumors of the skeleton. Breast cancer is the most frequent primary tumor with osseous metastases followed by renal cell carcinomas, bronchial carcinomas, and thyroid tumors. The predominant localization of bone metastases is the spine, followed by the pelvis, femur, ribs, skull, sternum, and humerus. The overall incidence of bone metastases has increased due to improved diagnosis, prolonged survival by adjuvant therapy, and improved follow-up. Osseous metastases of the pelvis are usually diagnosed only late in the course of the disease because of their considerable delayed onset of clinical symptoms. Therefore, treatment is usually focused on a palliative approach to reduce pain and to improve the quality of life. We introduce three patients with bronchial, renal cell, and cholangiocellular carcinoma in an incurable tumor stage with osseous metastases in the pelvis. The metastatic osteolyses caused pain and symptoms of instability. Despite high doses of opiate analgesics, the patients were neither free of pain nor could they be mobilized. The palliative treatment included preoperative tumor embolization followed by tumor resection and implantation of a hip prosthesis. The preoperative embolization reduced intraoperative bleeding and made tumor resection, osteosynthesis, and implantation of the hip prosthesis possible. Mobilization with moderate pain could be achieved in these three patients for the rest of their lives.

Adult↗
PubMed1981

[Development of clear zone after total hip replacement (author's transl)].

For studying the durability of Charnley-Müller's total hip prosthesis, 141 joints of the cases which had past at least 5 years from the operation were followed up by means of X-ray pictures to reveal the processes of CZ (clear zone at the interface between bone and cement) progress and loosening generation. Results 1) CZ which occurred once never disappeared and progressed in many cases. 2) The progress of CZ was supposed to be related to age and disease, but no relation was recognized with biomechanical factors. 3) The incidence of CZ was 83.7% on the acetabular side and 49.6% on the femoral side. 4) CZ of Stage I and II occurred within 1 year after the operation in many cases and CZ of Stage III and IV tended to increase about 3 years and 4 years after the operation, respectively, in the acetabular side, while in the femoral side Stage I occurred within 1 year in many cases, Stage II and III increased about 3 years after and Stage IV did about 4 years after. 5) The term for progressing from a stage to the next one considerably varied till Stage III, including non-progressive cases, but the term from Stage III to Stage IV was within 3 years in all the cases. 6) The durability of Charnley-Müller's total hip prosthesis observed in X-ray pictures was as low as 63.1%, 89 out of 141 joints 5 years after the operation, and it would be lower for a long time. The durability was particularly low in young cases of osteoarthritis. 7) The X-ray findings of loosening preceded clinical findings; thus precise interpretation of X-ray findings is useful for decision of prognosis and therapy.

Adult↗
PubMed1992

[Cemented bipolar prosthesis in multimorbidity patients with coxarthrosis. Short- and intermediate-term results].

The treatment of coxarthrosis with the cemented Duopleet prosthesis represents an efficient alternative to total hip prosthesis in elderly and polymorbid patients. The early results show a tolerable rate of complications. The patients can be mobilized early. The mortality seems to be low. Medium-term results are satisfactory. The rate of protrusions is lower than in patients with common femoral head prosthesis. Paraarticular ossifications are seen frequently. In numerous patients we found pain with projection to the operated hip.

Aged↗