RESUMO
Objective: To investigate the femoral bone remodeling and long-term effectiveness of total hip arthroplasty (THA) with anatomic medullary locking (AML) prosthesis. Methods: The clinical data of 24 cases (26 hips) who were treated with THA with AML prosthesis between November 1997 and January 2003 were retrospectively analyzed. There were 12 males and 12 females with an age of 32-69 years (mean, 53.7 years). There were 5 cases (5 hips) of avascular necrosis of the femoral head, 6 cases (7 hips) of secondary osteoarthritis of the hip dysplasia, 6 cases (6 hips) of femoral neck fracture, 2 cases (2 hips) of primary osteoarthritis, 3 cases (3 hips) of revision surgery, 1 case (2 hips) of ankylosing spondylitis, 1 case (1 hip) of femoral head fracture. The patients were followed up at immediate, 6 weeks, 3 months, 6 months, 1 year, and then every year after operation for imaging evaluation (X-ray film was taken immediately after operation to evaluate the femoral isthmus compression, Engh standard was used to evaluate the biological fixation of the femoral shaft prosthesis, and Brooker method was used to evaluate the occurrence of heterotopic ossification); bone reconstruction evaluation [reconstruction of prosthesis and bone interface (type of bone reaction, Gruen zone, incidence, and occurrence time were recorded), reconstruction of bone around prosthesis (proximal femur stress shielding bone absorption was evaluated according to Engh and Bobyn methods, and bone mineral density change rate was measured)]; clinical efficacy evaluation [Harris score for efficacy, visual analogue scale (VAS) score for thigh pain]. Results: All patients were followed up 15 years and 2 months to 20 years and 4 months, with a median of 16 years and 6 months. At immediate after operation, 24 hips (92.3%) had good femoral isthums compression, 24 hips (92.3%) had good bone ingrowth. Heterotopic ossification occurred in 2 patients with degree 1, 2 patients with degree 2, and 1 patient with degree 3 at 3-6 months after operation. Hyperplastic bone reactions were more common in Gruen 2, 3, 4, 5, 6, 10, 11, and 12 zones, mainly occurring at 6-20 months after operation, with the incidence of 3.8%-69.2%, with the highest incidence of spot welding. All absorptive bone reactions were osteolysis, which was common in Gruen 1 and 7 zones, and mainly occurred at 8 years after operation, with an incidence of 42.3%. No clear line (area) or enlarged sign of medullary cavity was observed. Twenty-one hips (80.8%) had 1 degree stress shieding, and 5 hips (19.2%) had 2 degree stress shieding. It mainly occurred at 10-24 months after operation in Gruen 1 and 7 zones. Dual energy X-ray absorptiometry showed that bone mineral density mainly decreased in Gruen 1, 2, 6, and 7 zones, mainly increased in Gruen 3, 4, and 5 zones. Bone mineral density loss progressed slowly after 2 years of operation, and it was stable in 5-8 years, but decreased rapidly in 8-9 years, and stabilized after 10 years. The Harris score increased from 51.1±6.2 before operation to 88.3±5.1 at last follow-up ( t=-21.774, P=0.000). Mild thigh pain occurred in only 2 cases (7.7%) with the VAS score of 2. No aseptic loosening or revision of femoral prosthesis occurred during the follow-up. Conclusion: The application of AML prosthesis in THA has a good bone remodeling and a good long-term effectiveness.
RESUMO
Introducción: Ante el difícil y cada vez más frecuente escenario de una revisión de cadera, existen diferentes alternativas para conseguir una fijación estable y duradera del componente femoral. El objetivo de este estudio fue evaluar la evolución clínica y radiográfica de los pacientes sometidos a una revisión del componente femoral con tallo cilíndrico de superficie rugosa extendida. Materiales y Métodos: Se llevó a cabo un estudio multicéntrico y retrospectivo de 148 pacientes, operados entre marzo de 1997 y marzo de 2010, a quienes se les realizó una cirugía de revisión femoral con un tallo cilíndrico con recubrimiento poroso. La edad promedio era de 63.1 años. Resultados: El seguimiento promedio fue de 7.7 años. En 134 (89,9%) pacientes, se observó una fijación ósea estable; en 12 (8%), una fijación fibrosa estable y, en 3 (2%), una fijación fibrosa inestable. El puntaje de Harris se modificó de 41 en el preoperatorio a 92 después de la cirugía. Las complicaciones fueron infección profunda (2 casos, 1,3%), fractura de fémur intraoperatoria (12,8%) y luxación protésica (3 casos, 2%). Conclusión: Los tallos cilíndricos con recubrimiento poroso han demostrado ser un eficaz recurso para solucionar la mayoría de las revisiones femorales por la posibilidad de obtener fijación estable a corto y largo plazo. Nivel de Evidencia: IV
Introduction: In the set of hip revision surgery there are different options to achieve a stable fixation of the femoral component. The objective of this study was to evaluate the clinical and radiographic outcomes of patients who underwent hip revision with cylindrical extensively porous stem. Methods: Between March 1997 and March 2010 a multicenter retrospective study was performed in 148 patients who underwent hip revision with cylindrical extensively porous stem. The mean age was 63.1 years. Results: The follow-up was 7.7 years. One hundred thirty-four (89.9%) patients achieved a stable bone ingrowth fixation; 12 (8%) a stable fibrous fixation and 3 (2%) a non-stable fixation. The Harris Hip Score improved from 41 points before surgery to 92 points in the postoperative period. Complications included: two deep infections (1.3%), 12 intra-operative femoral fractures (8%) and three hip dislocations (2%). Conclusion: The cylindrical extensively porous femoral stem seems to be a reliable technique for femoral hip revision surgery, as it is possible to obtain a short- and long-term stable fixation. Level of Evidence: IV