Ceramic-ceramic in total hip arthroplasty. An analysis of 7-13 year survival rate.

After 7-13 years, the long-term results of primary replacement of the hip joint by total cemented arthroplasty, with a head and acetabulum in high-density alumina, and a stem in chrome-cobalt alloy in a series of 38 patients were analyzed. The age of the patients ranged from 36 to 76 years (mean 55 years). The patients were monitored annually, by both clinical-radiographic follow-up and by an interview over the telephone (pain, independence walking, degree of hip flexion). The presence of a correlation between loosening of the implant and several clinical parameters (age, sex, diagnosis) and radiographic parameters (orientation, height and lateralization of the acetabular cup, rotation center of the implant, position of the femoral stem) were searched for. Data concerning 35 of the 43 prostheses implanted were gathered. The data were analyzed by the survival curve with an actuarial method, log-rank test and chi square test. The differences were considered significant for p < 0.05. There were no clinical or radiographic signs of loosening of the femoral prosthetic component. Instead, the acetabular cup was loosened in 7 cases. An implant was removed because of infective complications 6 months after surgery. The cumulative percentage of survival of the implant after 13 years was 81.2%. There was no statistically significant correlation between loosening of the implant and the parameters considered. Despite the favorable mechanical features of bioceramics, the acetabular component proved to be the weak point of the implant. The authors believe that only the introduction of new concepts of acetabular fixation could contribute to a significant increase in the survival rate for ceramic-ceramic.

Allergy to components of total hip arthroplasty before and after surgery.

Sensitivity to a series of haptens was studied in two groups of patients by means of patch tests. The first group was made up of 66 patients with total hip replacements, 12 of whom had aseptic loosening of the implant. The second group, which was used as a control, consisted of 41 patients scheduled to undergo total hip replacement. Ten patients (15.1%) in the first group tested positive; one of these had aseptic loosening. In the control group, two patients (4.8%) tested positive. The theory that an allergy may be the cause of loosening has a biologic foundation, but it can only be used to explain a few cases. However, since considerable vanadium sensitivity was found, we suggest that this material be used as little as possible in the manufacturing of prosthetic components.

Fractures and osteoporosis.

The prevention of fractures in the elderly population has become a primary objective of public health because of the costs involved, in both economic and social terms. The present effective method for measuring bone mass has called attention to the relationship between osteoporosis and the risk of fracture. A reduction in bone mass is a determining factor, but not in itself sufficient for an overall understanding of the problem. This study collates anatomical, physiological, biomechanical and epidemiological data, which makes it possible to evaluate the different factors involved in predicting fractures in subjects affected with osteoporosis.

[Bone mass in males. A comparison between dual-photon densitometry of the lumbar spine and the whole body]. / La massa ossea nei maschi. Confronto tra densitometria a doppio raggio fotonico della colonna lombare e whole body.

In order to evaluate the validity of a new method for measuring the whole body mineral content in diagnosing senile osteoporosis we studied 3 groups of male subjects: the first one composed by 40 young healthy subjects (mean age 24.7 years), the second composed by 40 normal patients (mean age 51.3 years); the 3rd group consisted of 26 elderly patients affected with typical osteoporotic fractures (mean age 77 years). All of them underwent a measurement of the spine as well as whole body mineral content performed with a dual photon absorptiometer. The measurements showed a decreasing in mineral content in the second versus the first group but a high correlation coefficient between spine and WB measurements characterized both groups; a striking decrease of it (r = 0.22) was found in the 3rd group. The relative unreliability of the spine measurement in elderly is probably due to the age-linked anatomical alteration. We therefore conclude that WB measurement must be considered the method of choice for the detection of senile osteoporosis.

Vitamin D concentrations in women of postmenopausal age with fractures of the femoral neck.

Thirty-eight women of postmenopausal age, suffering from fractures of the femoral neck or vertebral bodies were studied in relation to differences in bone metabolism. The blood and urinary changes concerned in mineral and bone metabolism were recorded within 10 days of trauma, and in some femoral neck fractures, a histological study of the femoral heads removed in the course of prosthetic substitution was carried out. The patients with femoral neck fractures were older than those with vertebral fractures and had metabolic and histological findings suggestive of osteomalacia. A particularly significant difference between the two groups was the plasma level of 25 hydroxycholecalciferol, which was lower in femoral neck fractures, and the urinary excretion of calcium, which was also more reduced in femoral neck fractures. A deficit of vitamin D hepatic metabolite thus appears to be a risk factor for femoral neck fractures in old patients.

[Kinesiology in thromboembolic prophylaxis in patients treated for lateral fracture of the femur neck]. / La kinesiologia nella profilassi tromboembolica in pazienti trattati per frattura laterale del collo femorale.

A kinesiological schema designed to facilitate functional recovery and prevent postoperative thromboembolism secondary to venous stasis in patients given surgical osteosynthesis for fractures of the femoral neck is presented.

Singh's method of the radiological quantitative evaluation of osteoporosis compared with the densitometric method.

The quantitative evaluation of osteoporosis by Singh's radiographic method, which is based on analysis of the trabecular pattern of the upper end of the femur, recognises seven successive grades of bone loss. This method has been shown, by comparison with bone densitometry, to be reliable both for the quantification of osteoporosis and as a screening method for early diagnosis. The method is sufficiently precise, and is not affected by independent factors such as variations of radiographic technique and the individual characteristics of the subject being tested.

[Endogenous thermotherapy in patients with prosthesis and metal implants]. / La termoterapia endogena nei portatori di protesi e di mezzi di sintesi metallici.

The conditions where metallic implants may be exposed to metric and centimetric electromagnetic irradiation have been experimentally produced "in vitro". Irradiation doses equal to those currently chosen for human physiotherapy, induce temperature increases which seem to be well tolerated by muscular and connective tissues. Conditions of maximal temperature increase around the metallic implant are those where the relative position of the electrodes to the body segments never occurs in practice.