Biomedical subjects

A Toni

Publications and source records attributed to A Toni.

196 records · Page 11Linked to original sources

PubMedDate not supplied

Arthroplasty in the ankylotic hip.

A total of 30 cases submitted to arthroplasty for the treatment of ankylotic hip are reported. The clinical results show that movement improved in 63% of the cases, with recovery of normal joint excursion in 37%. Severe limping consequent to hypotrophy of the gluteal musculature persisted in 62% of the cases, requiring the use of two canes in 17% of the patients. There was pain < or = 3 based on the Merle D'Aubigné and Postel evaluation scale in 13% of the patients, while 87% remained totally asymptomatic. Radiographic results were favorable: the incidence of aseptic loosening 86 months after surgery in 25 cemented prostheses was 20% for the acetabulum and 12% for the stem, while the 5 cementless prostheses were stable an average of 27 months after surgery. The incidence of aseptic loosening was greater in patients < or = 45 years of age (30% vs 10%). Early complications included dislocation (6.6%), caused by hypotrophy of the gluteal musculature secondary to the ankylosis. Leg length discrepancy, which was present preoperatively in 10 cases with an interval ranging from -5 to 6 cm (mean 3 cm), was corrected in 6 cases and reduced by half in the remaining 4 patients.

Adult↗

PubMedDate not supplied

A computerized morphometric evaluation of x-ray films for preoperative planning of hip arthroplasty.

Methods for measuring metric size on radiograms constitute an instrument of proven utility. For example, when preoperatively evaluating hip arthroplasty the diameter of the medullary canal and the cervicodiaphyseal angle, must be measured in order to determine the center of rotation of the femoral head, and to establish the flare index of the diaphyseal canal. These results may be obtained by using a computer-controlled graphic table to place the coordinates for the areas of greater anatomical and physiological importance on the radiologic image. Thus, a calculation of distances, anatomical axes and angles is obtained immediately, accurately defining the morphometry of the joint. In this study, the anteroposterior preoperative radiographic views of 87 femurs in 84 patients were evaluated by this method. The values provided by the morphometric analysis were then related to sex, age and weight. The diaphyseal canal was classified by typology for the preoperative planning of hip arthroplasty.

Adult↗

PubMedDate not supplied

Fragment fracture of the femoral head: a description of two cases.

Fragment fracture of the femoral head is a rare occurrence. The authors report two cases, in both of which there was dislocation of the hip, that was reduced non-surgically without at the same time obtaining reduction of the fractured fragment. In the first case the fragment was removed surgically while in the second case it was treated non-surgically as the cephalic lesion was unknown. At clinical-radiographic follow-up 2 years later, there was good functional recovery with no pain in the first patient, while early arthrosis developed in the second patient requiring prosthetic replacement surgery.

Adult↗

PubMedDate not supplied

The state of the art of non-invasive diagnostics for bone densitometry. Methods of photonic absorption.

The authors examine densitometric diagnostics by photonic absorption for the in-vivo determination of bone mass. Based on an analysis of the literature a comparison is made for values for accuracy, repeatability, and dosimetry offered by techniques such as single-energy photon absorptiometry (SPA), dual photon absorptiometry (DPA), dual-energy X-ray absorptiometry (DXA), or quantitative computer tomography (QCT). Also discussed are economic aspects and daily management, recent developments and future possibilities. None of the densitometric diagnostics examined is capable of entirely satisfying the different needs of measurement, and nearly all of the methods of photonic absorption reported here have specific indications. The coexistence of different systems will increase the priority of the definition of standardized protocols of calibration, so as to obtain densitometric data that may be compared.

Absorptiometry, Photon↗

PubMedDate not supplied

Fracture of the ceramic epiphysis in hip arthroplasty.

Between November 1985 and October 1993, a total of 694 ceramic-ceramic hip arthroplasties were implanted; up until 1987 the alumina used in the first 82 cases was Ostalox, produced by IMEC of Caravaggio, characterized by poor control of the size of the crystals; after 1987 Biolox alumina of the Feldmhule company was used in 612 cases. Fracture of the ceramic head occurred in 2 cases; in both patients ceramic was of the Ostalox type, meaning a 2.4% incidence of fracture; up until the present none of the 612 Biolox heads has presented this complication.

Aluminum↗

PubMedDate not supplied

The effect of autoclaving on the mechanical properties of bank bovine bone.

Xenologous bone grafts are frequently used in modern orthopaedic surgery. There is a risk of infection associated with the transmission of diseases among different species for these types of grafts. As for bovine bone grafts in recent times attention has been paid to the diffusion in various countries of the European Economic Community of "bovine spongiform encephalopathy"; this pertains to the same group of encephalopathies as Creutzfeldt-Jakob disease which strikes humans and has a lethal outcome. Thus, in the absence of clinical evidence, there is a potential source of risk of infection associated with specimens of bovine origin in relation to which a document of the European community suggests proceeding by sterilization by autoclaving at 132 degrees C. for at least 1 hour. It is the purpose of this study to verify the effect of this treatment on the mechanical properties of bone graft. The results show how this procedure reduces the graft's resistance to compression by approximately 70%. Thus, it is not acceptable for all bone grafts for which good mechanical resistance is required. In cases such as these, bovine bone grafts may be used only when the immunity of the farm of origin has been certified; then sterilization may be conducted using methods that are less destructive for the mechanical integrity of the bone tissue.

Animals↗

PubMedDate not supplied

The use of cobalt therapy to prevent heterotopic ossification after total hip arthroplasty.

The occurrence of heterotopic ossification after total hip arthroplasty may be prevented by radiation or medical therapy. The authors report the results obtained in 96 cases treated by cobalt therapy: the occurrence of high grade ossification (Brooker III and IV) is equal to 1% in cases treated, as compared to 9% in cases not treated. Male patients of advanced age and who are characterized by primary arthrosis are more at risk for ossification.

Adult↗

PubMedDate not supplied

Wear of the epiphysis-acetabulum in total hip arthroplasty: a review of the literature.

Problems related to the use of total hip arthroplasty and the properties of the materials used to make prostheses have encouraged wear phenomena of the epiphysis-acetabulum combination of international importance and acknowledgement. Based on a review of the literature, the authors analyze the most recent years of study of wear phenomena and discuss the choice of materials to be used in total hip arthroplasty implant, with particular interest in any potential defects.

Acetabulum↗

PubMedDate not supplied

Removal of heterotopic ossifications followed by cobalt therapy after hip arthroplasty.

The authors report 7 cases in which removal of high grade ossification which developed after hip arthroplasty was performed: all of the patients were treated postoperatively by radiation therapy with the purpose of preventing recurrence of ossification. After surgery ossification was present, but to a moderate degree, in 6 out of 7 cases examined; movement had clearly improved. The results obtained show that removal surgery is justified if movement of the hip is considerably impaired (ankylosis) and that prevention plays an essential role and must be carried out every time that the patient risks the development of ossification.

Aged↗

PubMedDate not supplied

Hydroxyapatite as metallic prosthesis coating: preliminary clinical experience.

The authors report the radiographic results of 65 An. C.A. prosthetic stems coated with hydroxyapatite and followed-up at least 24 months after implantation. A comparison with a homogeneous group of aluminum-coated An.C.A. stems showed that hydroxyapatite-coated stems are characterized by better osteointegration, with a clearly inferior incidence of radiolucent lines at the bone/prosthesis interface. Macroscopic observation and histologic examination carried out on two stems removed because of persistent pain to the thigh revealed partial resorption and fragmentation of the coating. The authors believe that this phenomenon, the object of other observations reported in the literature, may indicate the reduced stability of the coating in the long run, and as such further in-depth study is required.

Aluminum↗

PubMedDate not supplied

Antibiotic and antithromboembolic prophylaxis in hip arthroplasty (a review of 700 primary implants).

The authors report the results obtained with antibiotic and antithromboembolic prophylaxis used in 700 consecutive primary total hip arthroplasties. As for antibiotic prophylaxis (5 cases of infection: 0.7%) the various types of antibiotic used always kept the infection rate under 1%, confirming the effectiveness of the preventive use of antibioticotherapy. The incidence of deep venous thrombosis and pulmonary embolia were 3.7% and 0.7%, respectively (26 cases of DVT and 5 of PET). The incidence of DVT rose to 34.4% in a selected group of cases in which phlebography had been carried out even in the absence of symptoms of DVT. This confirms that the routine use of this method would without a doubt be useful in preventing complications with a high risk for the life of the patient (pulmonary embolia). As for pharmacological prophylaxis, indobufene and calcium heparin were the drugs used most: their effectiveness was nearly similar, despite the fact that the use of calcium heparin in patients considered to be at a higher risk for thromboembolic complications should be made clear.

Adult↗

PubMedDate not supplied

Hip arthroplasty in the elderly patient: is it a correct indication?

The authors report the results of 54 primary hip arthroplasty implants performed in patients aged over 75 years. The cases examined demonstrated that this type of surgery is not contraindicated in elderly patients as the occurrence of complications and perioperative risks are not higher if compared with a "younger" population. Preoperative anesthesiological evaluation that is extremely accurate is required.

Age Factors↗

PubMedDate not supplied

Intraoperative fractures of the femur in prosthetic hip reimplantations.

A total of 19 cases of intraoperative fractures of the femoral diaphysis occurring during prosthetic hip reimplantation are described. Incidence, predisposing factors, treatment, and influence on long-term results are discussed. The pre-existence of osteolysis or narrowing of the femoral cortex, often associated with primary cemented implantation with a metal-polyethylene combination, constitutes a factor that predisposes the patient to fracture. Fracture consolidation occurs in most cases with minimum treatment, at times without instrumentation; fracture, however, always means a delay in weight-bearing and a slowing down in recovery times. Long-term clinical evaluation shows functional results that are worse for reimplantations complicated by fracture as compared to those where there are no complications. The differences in the radiographic results instead do not reveal statistical significance.

Aged↗

PubMedDate not supplied

Metallic wear debris in dual modular hip arthroplasty.

Two cementless hip arthroplasty models with a modular neck made titanium alloy were submitted to cyclical loading in air, in physiological solution, and in a solution for accelerated corrosion tests in order to study the damage process of modular couplings. Thereafter, on one of the two models a series of tests were conducted in order to evaluate the quality of debris produced by the couplings. The parameters of testing adopted allow us to estimate the production of metallic debris observable in vivo with this type of prosthetic stem. The results show that the couplings of modular prostheses may be the source of metallic debris. The amount of debris produced depends on the geometry of the coupling and of the entire implant. Good planning and realization of the couplings, however, reduce the phenomenon that is negligible as compared to other potential sources of debris such as the surface of the stem or of the prosthetic head.

Bone Substitutes↗

PubMedDate not supplied

Computerized mechanical validation of custom-made stems.

The new community laws regarding medical devices require that custom-made devices be prescribed by the surgeon, who assumes responsibility for the device along with the manufacturer. It is the purpose of this study to indicate a method that allows use to check whether custom-made prostheses in particular conform to the requirements established by European laws; these are prostheses produced in a single model and that have rather short development and realization times. The pre-clinical method of validation proposed, based on a calculation with finite elements, was first verified by in vitro measurements and then used to evaluate 15 cases selected among the most critical ones in terms of size and/or geometrical irregularity from a group of 100 stems that had already been implanted. The method proposed was confirmed to be accurate and reliable; in 3 out of 15 stems analyzed we found values for mechanical resistance that were less than minimum values required by law.

Arthroplasty, Replacement, Hip↗

PubMedDate not supplied

Metal-UHWMPE (Ultra High Molecular Weight Polyethylene) wear: experimental testing.

Testing conducted on a hip joint simulator verified the Charnley hypothesis that the diameter of the prosthetic head is proportional to wear. The study was conducted by pairing heads in Ortinox TM with acetabular cups in polyethylene at high molecular weight (UHMWPE). A comparison between the different sizes of the heads (26 and 30 mm in diameter) showed a different trend in the wear rate; in particular, the head with a smaller diameter behaves better tribologically than the head with a larger diameter.

Acetabulum↗