RESUMEN
The algorithm differentiates between several surgical treatment options depending on the duration of the infection, on the amount of soft tissue damage, on the stability of the implant and the type of micro-organism. If the symptoms of infection exist for less then 3 weeks, a radical debridement is indicated under the condition of a stable implant and good soft tissue conditions. A one-stage exchange is possible with satisfactory conditions of soft tissue and the absence of difficult-to-treat, resistant micro-organisms. In patients with sinustracts or compromised soft tissue, a two-stage exchange is necessary. The placement of a spacer combined with a short interval of 2-3 weeks until reimplantation is possible for easy-to-treat bacteria. For difficult-to-treat micro-organisms, an interval of 8 weeks without spacer until reimplantation is necessary. While stabilised by a fixateur extern, antimicrobial treatment is administered for the first 6 weeks. If the tissue specimens at reimplantation two weeks later do not show growth of bacteria or signs of acute inflammation, antimicrobial treatment can be discontinued. For all other above-mentioned treatment protocols, we administer antimicrobial treatment for a total of 6 months. We present the results of 40 consecutive infected total knee arthroplasties treated according to our algorithm, including a detailed presentation of the two-stage revision procedure.
Asunto(s)
Algoritmos , Artroplastia de Reemplazo de Rodilla/efectos adversos , Inestabilidad de la Articulación/etiología , Inestabilidad de la Articulación/prevención & control , Prótesis de la Rodilla/efectos adversos , Infecciones Relacionadas con Prótesis/terapia , Reimplantación/métodos , Anciano , Antiinfecciosos/uso terapéutico , Antiinflamatorios/uso terapéutico , Femenino , Alemania , Humanos , Masculino , Guías de Práctica Clínica como Asunto , Pautas de la Práctica en Medicina/normas , Pronóstico , Infecciones Relacionadas con Prótesis/etiología , Suiza , Resultado del TratamientoRESUMEN
INTRODUCTION: An increased revision rate of cemented titanium stems compared with cobalt chromium stems has been described after a short follow-up. In this paper, the minimum 10-year outcome after the implantation of titanium (Ti) and cobalt chromium ME (CoCr) Mueller straight-stem prostheses is analyzed in order to estimate the prognosis of the patients who were not revised. MATERIALS AND METHODS: . A total of 272 (Ti) straight stems were implanted between 1987 and 1990, and 161 (CoCr) straight stems were implanted from 1984 to 1987. Clinical and radiological checks were carried out prospectively after 1, 2, 5, and 10 years. RESULTS: The survival rate concerning aseptic loosening of the stem after 5 years was 92.8% (Ti)/100% (CoCr) and after 10 years 80.9%/98.2%. Thirty-six (Ti)/2 (CoCr) patients required revision of the stem due to aseptic loosening. The revision rate per year of the Ti stems increased until 7 years postoperatively and decreased thereafter. At the 10-year follow-up, 107 Ti and 84 CoCr implants were checked, and the subjective and clinical parameters did not differ between the two groups. CONCLUSION: Except for an increased subsidence rate of the stems in the Ti (31%) versus the CoCr group (16%), there was no statistically significant difference in the clinical and radiological outcomes.
Asunto(s)
Prótesis de Cadera , Anciano , Aleaciones de Cromo , Análisis de Falla de Equipo , Femenino , Estudios de Seguimiento , Humanos , Masculino , Diseño de Prótesis , Reoperación , TitanioRESUMEN
Time to revision is an important criterion describing the quality of implants in total joint surgery. Estimates of failure probabilities are required to inform a patient about the risk of suffering a reoperation. Also, regression models are used for comparing different prosthesis designs. Typically, patients dying before a revision are considered as censored for time to prosthesis failure. We argue that this technique is inadequate for estimation of failure probabilities and insufficient for comparison of different designs. We propose a new approach based on a competing risk model to account for concurrent mortality. We describe differences in the estimation of failure probabilities and in the interpretation of regression models for implant failure. Additionally, we introduce a random effects term in the regression model to account for potential dependencies in the failure times of bilaterally treated patients. The new approach is illustrated with fictitious data and data from an observational study conducted at a specialized hospital in Switzerland.
Asunto(s)
Artroplastia de Reemplazo de Cadera/instrumentación , Artroplastia de Reemplazo de Cadera/mortalidad , Análisis de Falla de Equipo , Prótesis de Cadera , Modelos de Riesgos Proporcionales , Análisis de Supervivencia , Anciano , Femenino , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Suiza/epidemiologíaRESUMEN
We studied the rate of aseptic loosening of three different types of femoral stems in primary total hip replacement. After a median follow-up of 10.2 years 4/147 CoCrNi (SS77) straight stems (type M.E. Müller) were revised. After a median follow-up of 7.7 years 32/239 Ti-6A1-7Nb (SS77) were revised and after a median follow-up of 5.2 years 52/203 SLS Titanium alloy stems were revised. Whereas the first two stems are of identical design (smooth-blasted, anterior and posterior collar), the SLS stem design is different. Surgical procedure and cementing technique have remained unchanged. There is a significantly higher risk of failure for smaller titanium stem sizes and in males and patients who are physically active. This indicates that the greater elasticity of the Titanium alloy is one of the factors responsible for loosening.