Disseminated intravascular coagulation during total hip replacement.

Disseminated intravascular coagulation (DIC) is an extremely serious hemorrhagic disorder and one that is potentially lethal. DIC is more frequently observed as a complication of obstetric pathologies, diffused neoplasms, bacterial sepsis, blood transfusions, traumas and adipose embolias. The literature reports very few cases occurring after total hip replacement, two of which the cause of death. In all of the cases described one or boh prosthetic components are cemented. The authors report a case observed after total hip replacement in a patient submitted one year previously to contralateral hip replacement. Severe hypotension, bradychardia and profuse bleeding of the wound and from the drainages one hour after suturing constituted the initial symptom. Recognition of the clinical findings, after exclusion of a iatrogenic lesion, and subsequent treatment in intensive therapy allowed us to save the patient. The syndrome must be suspected and immediately diagnosed when profuse bleeding that cannot be related to vascular lesion is observed immediately postsurgery after cemented or hybrid hip replacement. Confirmation through hematological tests and timely treatment in a specialized center are indispensable requirements to save the life of the patient.

Severe wear from retrieved alumina-on-alumina coupled implant: a case report.

This study details the in vivo wear behavior of an alumina acetabular cup and a femoral head on a retrieved non-cemented hip prosthesis. A commercial alumina ceramic-on-ceramic prosthesis was retrieved from a patient previously treated for bilateral hip arthrosis in "coxa profunda". Massive wear was found on the retrieved alumina ceramic head and acetabular cup. The total measured penetration depth was 1.9 mm while the total calculated weight loss for the acetabular cup was 6.06 g. The study underlines the head-cup instability caused by cup loosening as major cause of severe ceramic wear.

Hip arthroplasty after femoral osteotomy.

The authors report the results of 56 prosthetic implants on previous femoral osteotomy. The cases submitted to surgery, some time after the operation, present with clinical-radiographic results (movement and risk of loosening) that are worse than those cases that had not undergone osteotomy. Among complications, a higher incidence of intraoperative fractures and nerve paralysis were observed. Fractures always occurred when instrumentation was removed during the same prosthetic implantation procedure.

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.

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.

Wear in carbon fiber-reinforced polyethylene (poly-two) knee prostheses.

The authors report a case of massive wear of carbon fiber-reinforced polyethylene used as an insert in a knee prosthesis. The finding, which was studied under a scanning electron microscope, in agreement with mechanical resistance and laboratory testing reported in the literature, confirms that this composite material (poly-two) is not more advantageous to use that ultra-high molecular weight polyethylene in terms of wear, despite favorable experimental premises.

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.

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.

[Diagnostic approach to popliteal venous aneurysm]. / L'approccio diagnostico all'aneurisma venoso popliteo.

Venous aneurysms are rare vascular abnormalities and are often described in patients presenting with pulmonary embolism. The occasional real time ultrasound examination of an aneurysm of venous system in the popliteal fossa has focalized our interest in the diagnostic approach of this entity. In our experience and in the literature the physical examination is usually negative while the ultrasound gives high quality imaging combined to a Doppler evaluation, so this kind of diagnostic tool is desirable as a first approach. Both morphology and flow hemodynamics can be detected in a non invasive way. About wall aspect and surrounding tissue is underlined the MRT and CT scanning, the thrombotic extension is well inspected. The venography is the definitive study and should always be performed because it is the most reliable examination and specific until the sac of aneurysm is filled from the contrast. However this diagnostic modality is useful in the patient undergoing surgical repair.

Techniques for removal of the stem: transfemoral or intramedullary?

Since 1981 a total of 76 reimplantations of the prosthetic stem have been performed, substituting 52 cemented stems and 24 cementless ones. Only 7 patients (9%) required transcortical access, 3 of these stems (43%) were not osteointegrated, while of the 69 reimplantations performed by intramedullary approach, only 4% of the stems did not achieve skeletal stabilization. A total of 43% of the stems reimplanted using an intramedullary approach were short (12-13 cm). The advantages of intramedullary access may be summarized by saying that diaphyseal cortical bone is saved; in the use of short prosthetic models. The transcortical technique is limited to a minority of patients, particularly to cases where stems that show osteointegration and are cementless are removed.

[The popliteal artery entrapment syndrome. Clinical experience]. / Sindrome da intrappolamento dell'arteria poplitea. Esperienza clinica.

The authors report their experience in treating three cases of popliteal artery entrapment. The analysis is based on the onset and the gap of time between the symptoms and the diagnostic certainty referred to the age of the patients. The diagnostic approach and follow-up is discussed including magnetic resonance of popliteal fossa. The surgical approach was constantly a shaped dorsal incision, and the reconstruction was performed in two cases with carbon coated dacron grafts of 6 mm diameter for the inadequacy of veins available. Any true aneurysm formation was identified. All grafts are patent on follow-up and the viability of the popliteal artery that underwent to simply myotomy is confirmed too by doppler ultrasound. Any recurrence of symptoms is recognized, in only one case was observed a concomitant entrapment in the other leg, not treated now is underlined. The advantage available for the patient in a physiokinetic therapy program, forerunner of a complete functional restoring, especially in athletic patients.

Computer aided densitometric image analysis of bone remodelling after total hip arthroplasty.

By means of a simple and inexpensive system, the computer aided densitometric image analysis (CADIA), we can now evaluate on X-ray film the effect of long term bone remodelling after total hip arthroplasties (THA). The results of CADIA system applied to the historical archive are burdened by a not always acceptable significance. The main source of error is the variance of radiological parameters. An attempt to retrieve the historical archive, that is of every X-ray film obtained out of any radiological control protocol, can be carried out with the bone density ratio representation. We have evaluated three different specimens with bone density ratio analysis: cementless group (96 cases), cemented group (59 cases) and non prosthetized femurs group (51 cases) as a control, all groups were followed up for more than 24 months. Ratios showed up different behaviour among the three specimens, confirming clinical evidence of a lower bone remodelling for cemented THA.