Peter Herberts

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The tibial components in 143 patients with total knee replacements performed before 1988 were assessed for micromotion using roentgen stereophotogrammetric analysis (RSA) over a period of 13 years. The fixation of the prostheses remained clinically sound in all cases, although revision had been required for other reasons in seven. In a second group taken(More)
Postoperative femoral periprosthetic fracture is an uncommon complication of total hip arthroplasty surgery, but several centers worldwide have recently reported an increase in total numbers of such fractures. This severe complication is costly for society and results in high morbidity. Our analysis of 1049 periprosthetic fractures occurring in Sweden(More)
Radiostereometric analysis is a science that enables reliable measurements to be made from radiographs. The method involves several steps including insertion of spheric tantalum markers, radiographic examinations, measurements of radiographic films, and calculations of three-dimensional movements. The precision of the method corresponding to the 99%(More)
A prospective, national multi-center study of all reoperations after total hip replacement (THR) was started by the Swedish Orthopedic Association in 1979. The material comprises all THR performed in Sweden, presently more than 10,000 yearly or 130 THR per 100,000 inhabitants; uncemented implants have been used in less than 2 percent. The main reasons for(More)
BACKGROUND The purpose of this study was to determine the demographics, incidence, and results of treatment of periprosthetic fractures in a nationwide observational study. METHODS In the years 1999 and 2000, 321 periprosthetic fractures were reported to the Swedish National Hip Arthroplasty Register. All of the associated hospital records were collected.(More)
The Swedish Hip Register has defined the epidemiology of total hip replacement in Sweden. Most hip implants are fully cemented. Serious complications and rates of revision have declined significantly despite an increasing number of patients at risk. During the past 5 years, only 8-9% of hip replacements are revisions. Aseptic loosening with or without(More)
BACKGROUND Laboratory tests and early clinical studies have shown that highly cross-linked polyethylene (PE) markedly improves wear resistance compared to conventional PE. We evaluated this type of PE in two randomized clinical studies using radiostereometric analysis (RSA). The 2- and 3-year follow-up of these studies have already been reported. We found a(More)
The myoelectric activity of some of the posterior muscles of the back was studied quantitatively using signal amplitude estimation and power spectrum analysis. Surface electrodes were placed on both sides of the trunk at T4, T8, L1, L3, and L5 levels. Four different angles of forward flexion were studied during external loading of the spine with 200 N. At(More)