Resultados a medio plazo de la artroplastia total de cadera metal-metal con cabeza de gran tamaño Magnum / Midterm results of Magnum large head metal-on-metal total hip arthroplasty

Objetivos: A raíz de las alertas sanitarias surgidas por la alta incidencia de recambios en la artroplastia de cadera metal-metal, se presentan los resultados obtenidos del seguimiento prospectivo de la serie de nuestro centro con cabezas de gran tamaño. Material y métodos: Se incluyeron todos los pacientes tratados con el cotilo Recap-M2a-Magnum, Biomet de 2008 a 2011. Se revisaron prospectivamente todos los pacientes registrando Harris Hip Score y síntomas de intoxicación por cromo-cobalto y se solicitaron niveles séricos de estos iones, radiografía y ecografía. Se solicitó resonancia magnética en caso de ecografía positiva. Resultados: Se incluyeron 26 varones de 48,54 años de edad media [32-62, DE: 7,18]. Se utilizó un abordaje anterolateral y vástagos Bimetric (7) o F40 (19). La moda de los diámetros cefálicos fue 46 [42-52]. La inclinación media del cotilo fue 39,35° [21-59°, DE: 9,78]. Durante el seguimiento (7,3 años [5,9-9,4 años, DE: 0,78]), 3 pacientes (11,5%) precisaron revisión (2 por movilización aséptica, un pseudotumor). El tiempo medio hasta la revisión fue 5,4 años [3,1-8,0, DE: 2,48]. La probabilidad acumulada de supervivencia fue del 88,5% (IC95% 76,3-100%). El Harris Hip Score fue de 94,47 [66,5-100, DE: 8,94] y los pacientes no mostraron ningún síntoma de intoxicación metálica, con niveles de cromo 1,88 mcg/dl [0,6-3,9] y cobalto 1,74 mcg/dl [0,5-5,6]. Se encontró un pseudotumor en un paciente asintomático y pequeñas cantidades de líquido periprotésico en 5 pacientes (19,2%). Discusión y conclusiones: Seguimos encontrando altas tasas de revisión al extender el seguimiento de los pacientes debido a la movilización aséptica y la formación de pseudotumores. La resonancia nuclear magnética no parece la prueba más adecuada para el estudio de las complicaciones de este tipo de prótesis

Objectives: We present the results of the prospective follow up of a sample of large head metal-metal total hip arthroplasty obtained after the safety alert regarding a higher incidence of revision of these implants. Material and methods: All patients implanted with the Recap-M2a-Magnum cup between 2008 and 2011 were included. They were prospectively reviewed recording Harris Hip Score, clinical symptoms of chromium or cobalt intoxication. Serum levels of these ions were requested as well as X-Rays and ultrasonography. An MRI was performed in the cases of positive ultrasonography. Results: Twenty-six males with a mean age of 48.54 years [32-62, SD: 7.18] were included. An anterolateral approach and Bi-Metric (7) and F-40 (19) stems were used. Cephalic diameters ranged 42-52 (mode: 46) and the mean cup inclination was 39.35° [21-59°, SD: 9.78]. During follow-up (7.3 years [5.9-9.4; SD: .78]), 3 patients (11.5%) underwent revision (2 cases aseptic loosening, 1 pseudotumour). Mean time until revision was 5.4 years [3.1-8.0; SD: 2.48]. The accumulated survival probability was 88.5% (95% CI 76.3-100%). Harris Hip Score was 94.47 [66.5-100; SD: 8.94] and the patients showed no metallic intoxication symptoms. The levels of chromium were 1.88 mcg/dl [0.6-3.9] and cobalt 1,74 mcg/dl [0.5-5,6]. One pseudotumour was found in an asymptomatic patient, and small amounts of periarticular liquid were found in 5 patients (19.2%) Discussion and conclusions: High revision rates are still found when follow up is extended due to aseptic loosening and pseudotumour formation. MRI might not be the most adequate test to study the complications of these prostheses

Midterm results of Magnum large head metal-on-metal total hip arthroplasty. / Resultados a medio plazo de la artroplastia total de cadera metal-metal con cabeza de gran tamaño Magnum.

OBJECTIVES: We present the results of the prospective follow up of a sample of large head metal-metal total hip arthroplasty obtained after the safety alert regarding a higher incidence of revision of these implants. MATERIAL AND METHODS: All patients implanted with the Recap-M2a-Magnum cup between 2008 and 2011 were included. They were prospectively reviewed recording Harris Hip Score, clinical symptoms of chromium or cobalt intoxication. Serum levels of these ions were requested as well as X-Rays and ultrasonography. An MRI was performed in the cases of positive ultrasonography. RESULTS: Twenty-six males with a mean age of 48.54 years [32-62, SD: 7.18] were included. An anterolateral approach and Bi-Metric (7) and F-40 (19) stems were used. Cephalic diameters ranged 42-52 (mode: 46) and the mean cup inclination was 39.35° [21-59°, SD: 9.78]. During follow-up (7.3 years [5.9-9.4; SD: .78]), 3 patients (11.5%) underwent revision (2 cases aseptic loosening, 1 pseudotumour). Mean time until revision was 5.4 years [3.1-8.0; SD: 2.48]. The accumulated survival probability was 88.5% (95% CI 76.3-100%). Harris Hip Score was 94.47 [66.5-100; SD: 8.94] and the patients showed no metallic intoxication symptoms. The levels of chromium were 1.88 mcg/dl [0.6-3.9] and cobalt 1,74 mcg/dl [0.5-5,6]. One pseudotumour was found in an asymptomatic patient, and small amounts of periarticular liquid were found in 5 patients (19.2%) DISCUSSION AND CONCLUSIONS: High revision rates are still found when follow up is extended due to aseptic loosening and pseudotumour formation. MRI might not be the most adequate test to study the complications of these prostheses.