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At least 235 records · Page 13Linked to original sources
PubMed2004

Salvage of a recurrently dislocating total hip prosthesis with use of a constrained acetabular component. A concise follow-up of a previous report.

We previously reported the results at a mean of five years following the use of a tripolar constrained acetabular component to treat recurrently dislocating total hip prostheses. In this study, we report the results after longer follow-up, with emphasis on the prevalence of implant loosening, osteolysis, and later recurrent instability. Fifty-five patients treated with a total of fifty-six constrained acetabular components because of recurrent dislocations of a total hip prosthesis (average, six dislocations; range, two to twenty dislocations) were followed for an average of 10.2 years (range, 7.0 to 13.2 years) or until death. Four (7%) of the fifty-six hips had a subsequent dislocation or failure of the device. Three femoral components (5%) and two acetabular components (4%) were revised because of aseptic loosening. One hip was revised because of osteolysis. We concluded that this constrained acetabular component provides durable protection against additional dislocations without substantial deleterious effects on component fixation. We use this device to treat recurrent dislocation when other modalities are unlikely to be effective.

Acetabulum↗
PubMedDate not supplied

Total hip prosthesis metal-artifact suppression using iterative deblurring reconstruction.

PURPOSE: CT of total joint prostheses is limited by metal artifact produced mainly by missing projection data. Iterative deblurring reconstruction is less sensitive to missing projection data than filtered backprojection. A software CT simulator was used to compare total hip prosthesis images reconstructed using standard filtered backprojection, filtered backprojection after linear interpolation of missing data, and iterative deblurring. METHOD: Unilateral and bilateral total hip replacements with metal-backed or all-polyethylene acetabular prostheses were simulated using bone, metal, and polyethylene annuli and circles of metal and water (soft tissue). Material attenuation properties were taken from the literature. The simulation assumed that no X-rays penetrated the metal. Simulated projection data were reconstructed using filtered backprojection, filtered backprojection after linear interpolation of missing data, and iterative deblurring. Visual observations and objective region-of-interest analyses were made. RESULTS: Even with no X-rays penetrating the metal, iterative deblurring produced almost no visible artifact within the bone or soft tissues. Bone edge detection and sizing were more easily and accurately done from the iterative deblurring images. All reconstruction techniques underestimated bone and water CT attenuation values. Metal artifact was worse for the bilateral or metal-backed prostheses. CONCLUSION: Iterative deblurring generated nearly metal-artifact-free images in this simulation. Filtered backprojection, even after linear interpolation, produced typical clinical metal-artifact images.

Artifacts↗
PubMed2000

[Alpha-1-antitrypsin in early infections after hip prosthesis surgery].

PURPOSE OF THE STUDY: The aim of this work was to determine whether erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and alpha-1-antitrypsin (A1AT) levels are correlated significantly with early postoperative infectious complications after hip prosthetic surgery. MATERIALS AND METHODS: This prospective study was conducted on 100 total hip replacements performed between 1994 and 1995. ESR, CRP and A1AT were obtained before surgery then at 1, 2 and 6 weeks after surgery. RESULTS: Seven bacteriologically proven cases of infection were reported. Infection was considered to be superficial if it did not extend deeper than the muscles fascia. There was a strong statistical correlation between A1AT level and infection for all postoperative times (p<0.0001). A1AT was highly sensitive (87.5 p. 100) and specific (85.8 p. 100) for infection compared with ESR (sensibility 70 p. 100 and specificity 65.9 p. 100) and CRP (sensitivity 63.6 p. 100 and specificity 80.1 p. 100). DISCUSSION AND CONCLUSION: In our hands, A1AT can be a most useful diagnostic tool for infection after prosthesis hip surgery. Although not totally specific, it is highly sensitive for infection compared with other tools such as ESR and CRP more frequently used. These findings suggest an avenue of research on the role of A1AT in infectious complications after prosthetic joint surgery.

Acinetobacter Infections↗
PubMed1994

Perioperative autologous blood transfusion in elective total hip prosthesis operations.

The aim of this study was to determine if acute perioperative normovolaemic haemodilution with retransfusion of the autologous blood at the end of operation would reduce or eliminate the need for homologous (banked) blood. Forty patients scheduled for total hip prosthesis replacement (THPR) were randomly divided into two groups: Group A, 20 patients from whom 900 ml of blood was taken 20 min preoperatively, the volume being replaced with 1000 ml of gelatin solution (Haemaccel). Group B, 20 patients who were undergoing the same operation but from whom no blood was taken. Both groups were allowed a fall in haematocrit (Hct) to 0.25 before transfusion was started. A standard formula to calculate allowable blood loss plus intraoperative Hct measurements were used to achieve the haemodilution. There was no significant difference in blood loss between the two groups. Transfusion requirement was the same in the two groups. In this study, autotransfusion by the withdrawal of 900 ml of blood is inadequate to reduce the transfusion requirement further than that which can be achieved by haemodilution alone.

Adult↗
PubMed1989

[A case of epidermoid carcinoma developing from contact with an articular hip prosthesis].

Several cases of sarcomas which developed in contact with joint prosthetic material were reported previously. They were mostly malignant fibrous histiocytoma, but to our knowledge, no case of epidermoid carcinoma was reported. We report here one case of epidermoid carcinoma which developed in contact with a hip prosthesis. Surgery was complicated by local infection and necessitated multiple reoperations, which may be responsible for the implantation of skin cells. It is generally admitted that multiple factors contribute to the development of a tumor clone. In our patient we must take into consideration such factors as chronic infection with fistula and prosthetic material. However carcinomas, even rare, which form on fistulas appear only after many years of suppuration. The short delay between the prosthesis setting and the carcinoma onset in our patients, suggests that a cofactor may have speeded up tumor induction. This cofactor could be the platelet derived growth factor (PDGF) in the case of sarcomas appearing on bone infarcts without foreign body introduction, and possibly other tumors.

Bone Neoplasms↗
PubMed1991

[Monitoring after total hip prosthesis. Value of semi-quantitative D-dimer assay].

Criteria for positive assay of the D-dimer were defined in order to establish its diagnostic value for phlebitis in the post-operative period. A retrospective study was carried out on the files of 94 patients who had received a total hip prosthesis in 1990. A semi-quantitative assay technique was used to measure the D-dimer because it is the only method giving immediate results. Three criteria were used to classify the results: criterium A: D-dimer greater than or equal to 2 micrograms/ml; criterium B: D-dimer greater than or equal to 4 times the preceding test; absence of both of these criteria. The results were compared to echo-doppler results and confirmed by phlebography when necessary. The incidence of proximal phlebitis was low (2 percent); criterium B showed a 100 percent negative predictability and a 29 percent positive predictability. None of the cases of phlebitis diagnosed with this test had been suspected clinically. This test provides a means of patient screening and spares the need for other explorations.

Echocardiography, Doppler↗
PubMed1954

Hip prosthesis.

Explore the source record for details and available documents.

Hip↗
PubMed1979

[A study of the stress distribution of the stem of the total hip prosthesis (author's transl)].

By attaching the strain gauges on the inner and outer sides of the stem of the total hip prosthesis composed of Müller, Charnley and domestic SOM type, the stress distribution was measured. At first, the center of the head of the prosthesis and the apex of the stem were adjusted to be on the vertical line, and a vertical load was placed on the uppermost end of the head, then the stress was measured. Next, the stem was fixed in the hole of a wood-block containing acrylic resin, and the load was placed on the head in neutral, 10 degrees valgus and 10 degrees varus position and in the direction same as the stem before fixation, then the stress was measured of respective position. In comparing the difference in stress distribution between the fixed and the non-fixed stem, the stress in the case of the fixed stem proved to be 17--32% that of the non-fixed one. The site where the maximum stress appeared was at the middle third of the stem in the case of the non-fixed stem, while it was at the neck and at the one fifth of the upper portion of the fixed one. In comparing the stress at the neutral, the valgus and the varus position, the stress at the valgus position was found to be minimum, and taking the stress at the neutral position as 100, it was 60--82, and at the varus position the maximum of 105--131 appeared.

Biomechanical Phenomena↗
PubMed1992

[Calculation of optimized and individualized hip prosthesis. A study of feasibility].

As logical consequence of a series of basic research studies on human femoral bones with unipodal support and under static stress, performed with physicomathematic modelling methods (finite-elements method) then confirmed by direct visualization of deformations resulting from such stress using holographic interferometry, the authors have worked on the definition of an optimized and individualized hip prosthesis. Thick CT sections digitized with a table and entered into a specially programmed computer allowed three-dimensional modelling of the femur as a volume, i.e. with its external contour and its medullary canal, and therefore of the implantable space. The prosthesis was then defined taking a number of hypotheses into account: necessity to regularize cortical bone spicules inside spongious bone, which are so often present opposite the rough line, partial machining at the level of the calcar, reduced tail length, presence or absence of collar. Thus an optimized and individualized prosthesis was defined. A prototype corresponding to a given femoral bone could then have been produced. However, the authors found it preferable to use simulation with computer synthetic images to check easy insertion and removal.

Acetabulum↗
PubMed2000

Elevated interleukin-12 in pseudosynovial fluid in patients with aseptic loosening of hip prosthesis.

Loosening of a prosthesis is a major problem in total joint arthroplasty. To assess levels of cytokines in patients with such loosening, we measured the pseudosynovial fluid concentration of the following cytokines; tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, interleukin (IL)-1beta, IL-4, IL-6, IL-10, IL-12, matrix metalloproteinase (MMP)-1, and MMP-3. We examined the pseudosynovial fluid in patients with a loose hip prosthesis (group A; n = 8) and the synovial fluid in patients with osteoarthritis (OA) of the hip (group B; n = 18) using enzyme-linked immunosorbent assays. The mean concentration of IL-12 was significantly higher in group A than in group B (P < 0.01). Also, we found a significant (P < 0.05) correlation between the concentration of IL-12 and the concentration of MMP-1 in the patients with prosthesis loosening. The concentrations of TNF-alpha, IL-1beta, IL-4, IL-6, IL-10, IFN-gamma, MMP-1, and MMP-3 appeared to be similar in the two groups, although the small number of samples available precluded us from determining that there was no significant difference. The present study is the first to report elevated IL-12 levels in the pseudosynovial fluid of patients with a loose prosthesis. The immunoregulatory effect of IL-12 against wear particles could play an important role in causing loosening of the prosthesis.

Aged↗
PubMed1979

The results of reinsertion of a total hip prosthesis after sepsis.

Sixty-five total hip arthroplastics were reinserted after sepsis around the hip, positive cultures being obtained from fifty-six. Although 65 per cent of patients still have their implant in position, only sixteen of sixty-five (25 per cent) show an excellent or good result on a Harris rating. Twenty-three of sixty-five (35 per cent) subsequently required an excision arthroplasty. The indications and contraindications for this procedure are given.

Aged↗
PubMedDate not supplied

Range of motion caused by design of the total hip prosthesis.

In a clinical material of total hip prostheses, a study was performed of the range of femoral motion until impingement occurred between the neck of the femoral stem and the rim of the acetabular socket. The results were compared with the physiologic range of motion, and the clinically relevant motion restriction was measured. Restriction was most common in flexion. There was a correlation between the prosthetic design and the restriction due to impingement.

Aged↗
PubMed1987

The medium-term results of cementless Lord-type hip prosthesis.

The results of 58 cementless total hip prostheses (Lord madreporous type) were evaluated 4 to 7 years after implantation. The functional results were generally satisfactory, although in approximately half the cases some pain was still present. Radiographic examination allowed us to analyse the response of the diaphyseal bone to the different situations of the endomedullary implant. Acetabular wear, which is one of the factors which may influence the long-term results, was also evaluated.

Bone Cements↗
PubMed1992

Displacement of an uncemented acetabular component after dislocation of a total hip prosthesis. A case report.

Review of the literature reveals few reports of complications encountered with noncemented acetabular components; most concern problems with screw or cup placement, component wear or migration, or disassembly of modular components. No reports involving the displacement of a noncemented acetabular component were found. This is a case report of a patient in whom a noncemented acetabular component was dislodged after the closed reduction of a dislocated total hip prosthesis 4.5 weeks after surgery. In light of this case, the authors believe these reductions should be performed under general anesthesia with fluoroscopic guidance. Care must be taken at surgery to ream sufficiently and obtain proper cup fit and position. Finally, the authors recommend bicortical screw fixation to provide maximum contact and rigid fixation in the early postoperative period.

Acetabulum↗
PubMed1987

Chemical implant fixation using hydroxyl-apatite coatings. The development of a human total hip prosthesis for chemical fixation to bone using hydroxyl-apatite coatings on titanium substrates.

Sintered hydroxyl-apatite implants form very tight bonds with living bone but are susceptible to fatigue failure. Plasma-sprayed apatite coatings on titanium substrates overcome the fatigue problem. The static tensile substrate bond strength of the apatite coating is in excess of 85 megapascals (MPa) (12,000 psi). In a plug implant study designed to discount mechanical retention, a bone bonding shear strength of 64 MPa (9280 psi) was achieved, comparable to the strength of cortical bone. Histologic sections confirm the close bonding between apatite coating and living bone. In a canine total hip arthroplasty study, the apatite-coated implants proved far superior to the uncoated controls. Uncoated prostheses were surrounded by fibrous tissue and were easily extracted from the femur at any postoperative time. The apatite-coated implants were rigidly fixed within three weeks with demonstrable bone formation up to the implant surface. Bony defects up to 2 mm in depth were filled with bone within six weeks. The hypothetical mechanism of bone bonding is chemical. Hydroxyl-apatite coatings permit an implant fixation far superior to current methods using either cemented or cementless techniques. The plan is to study a human total hip prosthesis with hydroxyl-apatite coating for chemical fixation to bone.

Animals↗