El polietileno de alto entrecruzamiento no reduce el desgaste en la artroplastia total de rodilla / Cross-linked polyethylene does not reduce wear in total knee arthroplasty

Objetivo: Comparar dos pares de fricción (metal/polietileno de ultra alto peso molecular [UHMWPE], metal/polietileno de alto entrecruzamiento) mediante análisis cuantitativo y cualitativo de partículas de polietileno en líquido sinovial a los 3 años postintervención en pacientes portadores de prótesis total de rodilla (PTR). Material y métodos: Se llevó a cabo un estudio de cohortes prospectivo, aleatorizado, con evaluación ciega incluyendo 25 pacientes a quienes se intervino de PTR de manera bilateral, con 6 meses de diferencia. A los 3 años postintervención, se realizaron artrocentesis de rodilla a 12 pacientes y se analizaron las partículas de polietileno. Resultados: No se hallaron diferencias significativas en el número de partículas generadas por los diferentes insertos de polietileno a los 3 años tras la implantación de una artroplastia total de rodilla (3.000×: x¯ entrecruzado=849,7; x¯ UHMWPE=796,9; p=0,63; 20.000×: x¯ entrecruzado=66,3; x¯ UHMWPE=73,1; p=0,76). Tampoco existen diferencias significativas entre los 2 tipos de inserto, entre la posibilidad de encontrar partículas de forma elongada (χ2=0,19; p=0,66) ni redonda (χ2=1,44; p=0,23). Sin embargo, la probabilidad de encontrar partículas de forma fibrilar es 3,08 veces mayor en el UHMWPE. Conclusiones: El polietileno altamente entrecruzado no reduce significativamente la generación de partículas de polietileno en aquellos pacientes intervenidos mediante una artroplastia total de rodilla, con muestras a 3 años postintervención

Aim: To compare two different types of inserts: Ultra-high molecular weight polyethylene (UHMWPE) and cross-linked polyethylene with a quantitative and qualitative study of polyethylene wear particles in synovial fluid 3 years after total knee arthroplasty. Material and methods: A prospective, randomized, controlled cohort study with blinded evaluation was carried out on 25 patients undergoing staged bilateral total knee replacement, 6 months apart. Knee arthrocentesis was performed on 12 patients 3 years after surgery, and the polyethylene particles were analyzed. Results: No significant differences were found in the number of particles generated by the two different types of inserts at 3 years from total knee arthroplasty (3,000×: x¯ cross-linked=849.7; x¯ UHMWPE=796.9; P=.63; 20,000×: x¯ cross-linked=66.3; x¯ UHMWPE=73.1; P=.76). Likewise, no differences in the probability of finding elongated (χ2=0.19; P=.66) or rounded (χ2=1.44; P=.23) particles in both types of inserts were observed. However, the probability of finding fibrillar particles is 3.08 times greater in UHMWPE. Conclusions: Cross-linked polyethylene does not significantly reduce the generation of polyethylene particles in patients with total knee arthroplasty, 3 years after the surgical procedure

Cross-linked polyethylene does not reduce wear in total knee arthroplasty. / El polietileno de alto entrecruzamiento no reduce el desgaste en la artroplastia total de rodilla.

AIM: To compare two different types of inserts: Ultra-high molecular weight polyethylene (UHMWPE) and cross-linked polyethylene with a quantitative and qualitative study of polyethylene wear particles in synovial fluid 3 years after total knee arthroplasty. MATERIAL AND METHODS: A prospective, randomized, controlled cohort study with blinded evaluation was carried out on 25 patients undergoing staged bilateral total knee replacement, 6 months apart. Knee arthrocentesis was performed on 12 patients 3 years after surgery, and the polyethylene particles were analyzed. RESULTS: No significant differences were found in the number of particles generated by the two different types of inserts at 3 years from total knee arthroplasty (3,000×: x¯ cross-linked=849.7; x¯ UHMWPE=796.9; P=.63; 20,000×: x¯ cross-linked=66.3; x¯ UHMWPE=73.1; P=.76). Likewise, no differences in the probability of finding elongated (χ2=0.19; P=.66) or rounded (χ2=1.44; P=.23) particles in both types of inserts were observed. However, the probability of finding fibrillar particles is 3.08 times greater in UHMWPE. CONCLUSIONS: Cross-linked polyethylene does not significantly reduce the generation of polyethylene particles in patients with total knee arthroplasty, 3 years after the surgical procedure.

Osteotomía de Pelet modificada en el tratamiento del hallux valgus juvenil / Modified Pelet osteotomy in the treatment of juvenile hallux valgus

Objetivo. Se presentan 61 casos de hallux valgus juvenil tratados quirúrgicamente mediante la técnica de Pelet modificada. Material y método. En el periodo comprendido entre 1996 y 2002 se han revisado 37 pacientes, 30 mujeres y 7 hombres, con unas edades comprendidas entre 9 y 19 años, promedio de 14 años, a los que se les practicó dicha técnica. El seguimiento mínimo fue de un año. En todos los casos se ha llevado a cabo una osteotomía subcapital del primer metatarsiano según la técnica descrita por Pelet, colocando como osteosíntesis una barra de material biorreabsorbible. Se autorizó la carga a las 24 horas. Resultados. Se ha conseguido la consolidación en un promedio de 5 semanas. En todos los casos se ha logrado una mejora de los ángulos intermetatarsiano y de hallux valgus con buen resultado clínico y pocas complicaciones. Conclusiones. Creemos que la osteotomía de Pelet es una técnica adecuada para el tratamiento del hallux valgus juvenil y del adolescente ya que es capaz de corregir las alteraciones patogénicas más frecuentes en estos pacientes, al mismo tiempo que nos parece poco agresiva (AU)

Purpose. Sixty-one cases of juvenile hallux valgus are presented that were treated surgically through a modified Pelet technique. Materials and methods. Between 1996 and 2002, 37 patients were subjected to the above mentioned technique (30 females and 7 males). Mean age was 14 years (range: 9-19). Minimum follow-up was one year. In all cases a subcapital osteotomy of the first metatarsal was carried out according to the technique described by Pelet. The osteosynthesis material used was a bioresorbable rod. Weight-bearing was allowed at 24 hours. Results. Healing was achieved at 5 weeks on average. In all cases an improvement was obtained in the intermetatarsal and hallux valgus angles, with good clinical results and few complications. Conclusions. We believe that Pelet osteotomy is suitable for the treatment of juvenile and adolescent hallux valgus since it is a non-aggressive technique that can correct the most usual pathogenetic alterations seen in these patients (AU)