RESUMEN
BACKGROUND: Infected joint replacements can be treated with gentamicin-containing materials for implantation. This may lead to side effects, especially in patients with impaired renal function. CASE DESCRIPTION: A 74-year-old woman underwent two surgeries for an acutely infected hip replacement. Gentamicin sponges (Garacol) were implanted during both interventions. The day after the second operation, her serum gentamicin levels had risen to toxic values. This confirmed the suspicion that she had a kidney impairment which was probably caused by the implanted gentamicin-containing sponges. In order to limit kidney damage, the patient received continuous venovenous haemodiafiltration (CVVHD). Outpatient check-up 3 months later found that the creatinine levels in the serum of the patient had normalised. CONCLUSION: Locally administered gentamicin sponges for implantation can cause therapeutic serum levels leading to systemic side effects. It is advisable to check kidney function before using the sponges. If this is reduced, it is recommended to be cautious when using these sponges for implantation. In case of toxic elevated values, CVVHD can limit kidney damage - which is reversible, given time - by accelerating gentamicin excretion.
Asunto(s)
Antibacterianos/efectos adversos , Artroplastia de Reemplazo de Cadera/efectos adversos , Gentamicinas/efectos adversos , Infecciones Relacionadas con Prótesis/tratamiento farmacológico , Insuficiencia Renal/inducido químicamente , Anciano , Animales , Antibacterianos/administración & dosificación , Implantes de Medicamentos/efectos adversos , Femenino , Gentamicinas/administración & dosificación , Humanos , Infecciones Relacionadas con Prótesis/cirugía , Tapones Quirúrgicos de GazaRESUMEN
Patients suffering from rheumatoid arthritis typically have a poor subchondral bone quality, endangering implant fixation. Using finite element analysis (FEA) an investigation was made to find whether a press-fit acetabular implant with a polar clearance would reduce interfacial micromotions and improve fixation compared with a standard hemispherical design. In addition, the effects of interference fit, friction, and implant material were analysed. Cups were introduced into an FEA model of a human pelvis with simulated subchondral bone plasticity. The models were loaded with a loading configuration simulating two cycles of normal walking, during which contact stresses and interfacial micromotions were monitored. Subsequently, a lever-out simulation was performed to assess the fixation strength of the various cases. A flattened cup with good bone quality produced the lowest interfacial micromotions. Poor bone decreased the fixation strength regardless of the geometry of the cup. Increasing the interference fit of the flattened cup compensated for the loss of fixation strength caused by poor bone quality. In conclusion, a flattened cup did not significantly improve implant fixation over a hemispherical cup in the case of poor bone quality. However, implant fixation can be optimized by increasing interference fit and avoiding inferior frictional properties and low-stiffness implants.
Asunto(s)
Acetábulo/fisiopatología , Artritis Reumatoide/fisiopatología , Artritis Reumatoide/cirugía , Articulación de la Cadera/fisiopatología , Articulación de la Cadera/cirugía , Inestabilidad de la Articulación/fisiopatología , Modelos Biológicos , Adhesividad , Artritis Reumatoide/complicaciones , Simulación por Computador , Diseño Asistido por Computadora , Diseño de Equipo , Análisis de Falla de Equipo , Fricción , Humanos , Inestabilidad de la Articulación/etiología , Inestabilidad de la Articulación/prevención & control , Movimiento , Presión , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
We measured radiographically the polyethylene socket wear in 34 hip prostheses with a 32 mm Al2O3-ceramic head with a rotating bearing and in 37 prostheses with a "fixed" ceramic head. The mean follow-up was 12 years in both groups. The mean annual linear wear of the polyethylene was 0.034 and 0.069 mm, respectively, (Mann-Whitney U-test p < 0.0001) in the "rotation" and the "fixed" group. A rotating bearing between the head and neck in a modular total hip system seems to reduce socket wear as compared to fixed taper junctions.