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.

Ultrasonography in congenital dysplasia and immature hip in infants.

The authors report about the possibilities to evaluate correct and early diagnosis by ultrasonographic technique in congenital infant hip dysplasia. The authors report the data concerning 4666 infant hips studied by clinical and ultrasonographic examinations during the years 1990-1991. The cases have been divided according to the age of patients into three groups in the first group, infants less than 1 month old in the II group, infants one to 3 month old; and in the III group, infants 3 month old and over. The use of subdivisions according to age allows higher statistical incidence of dysplasia and immature hip. The newborns and infants included in this study were at their I ultrasonographic examination, had not an instrumental diagnosis of dysplasia, and were not orthopaedic treatment. Treatment with different types of retractors were made in patients with ultrasonographic diagnosis of dysplasia or immature hip, according to the type of dysplasia and age of patient. It has been observed, according to attendance, in the I group of age an high incidence of immature hip (38.03% versus 13.01% in II group and 2.18% in third group) and dysplasia (2.81% versus 0.07% in II group and 0.13% in III group of children). Ultrasonography is replacing conventional radiography as primary method for the diagnosis is of hip dysplasia and thereby, the evaluation of its treatment. The ultrasonography techniques, being harmless for the patient, simple to perform, non-invasive, and economical, make then attractive early diagnostic tools for screening infant congenital hip dysplasia. With early diagnosis, it is possible to begin immediate treatment of congenital dysplasia, resulting a quick resolution of pathological hip disorders. To achieve these results, it is necessary that the orthopaedic surgeon conducts an ultrasonographic examination.

Early diagnosis of congenital dysplasia of the infant hip by means of ultrasound screening.

The authors present a study carried out in 1990 analyzing the results of ultrasound screening of the infant hip in order to evaluate possible dysplasia. They stress the already unquestionable role of ultrasound screening as a valid, sensitive and useful device in the diagnosis of congenital dysplasia of the hip and emphasize that the earlier the examination is carried out, the easier it is to begin suitable treatment rapidly and with positive results. They recommend that ultrasound screening should be carried out by an orthopaedist in order to further shorten diagnosis and treatment times.