Effects from Extramedullary Design of Femoral Stem on Hip Contact Force: A Musculoskeletal Multi-Body Dynamic Study / 医用生物力学

Objective To investigate the effects of design parameters such as neck-shaft angle, femoral offset and anteversion angle of total hip arthroplasty ( THA) prosthesis on contact forces of the hip. Methods A musculoskeletal multi-body dynamic model of THA was established based on AnyBody software. The effects of single or multiple factors on hip contact force were studied when the neck-shaft angle, eccentricity and anteversion angle varied within ±10°, ±20 mm and ±10°, respectively. Results The maximum hip contact force increased by 26. 08% when femoral offset was reduced by 20 mm. The maximum hip contact force increased by 5. 99% when the neck-shaft angle increased by 10°. When the anteversion angle increased by 10°, the hip contact force decreased at 0% -24% of gait cycle, with the peak decreasing by 19. 16% . However, the hip contact force was significantly increased at 38% -70% of gait cycle, with the peak increasing by 67. 78% . Conclusions In extramedullary design of the femoral stem, based on reconstruction of the patient’s anatomical parameters, the offset of the femoral stem can be appropriately increased, and the neck-shaft angle and anteversion angle can bereduced to avoid increasing forces on the hip.

Analysis of factors associated with the influence of femoral stem anteversion after total hip arthroplasty / 中国修复重建外科杂志

OBJECTIVE@#To explore the related factors of femoral stem anteversion (FSA) after total hip arthroplasty (THA), so as to provide reference for clinical design of FSA before operation and reduce the risk of hip dislocation after arthroplasty.@*METHODS@#Ninty-three patients (103 hips) who underwent THA between October 2021 and September 2022 and met the selection criteria were selected as the study subjects. Among them, there were 48 males and 45 females with an average age of 58.5 years (range, 25-88 years). Body mass index was 18.00-37.84 kg/m 2, with an average of 24.92 kg/m 2. There were 51 cases (57 hips) of osteonecrosis of femoral head, 35 cases (39 hips) of hip osteoarthritis, and 7 cases (7 hips) of congenital hip dysplasia. Based on CT images, the following indicators were measured: preoperative femoral neck anteversion (FNA), preoperative femoral rotation angle (FRA), preoperative acetabular anteversion (AA), and preoperative combined anteversion (CA; the sum of preoperative FNA and AA); postoperative FSA and the change in femoral anteversion angle (the difference between postoperative FSA and preoperative FNA). Based on preoperative X-ray films, the following indicators were measured: femoral cortical thickness index (CTI) and canal flare index (CFI), the proximal femoral medullary cavity was classified according to Noble classification (champagne cup type, normal type, chimney type), neck-shaft angle (NSA), and femoral offset (FO). Pearson correlation analysis, one-way ANOVA, and Point-biserial correlation analysis were used to investigate the correlation between postoperative FSA, postoperative change in femoral anteversion angle, and patient diagnosis, proximal femoral medullary cavity anatomy type, gender, age, as well as preoperative FNA, FRA, AA, CA, NSA, FO, CTI, and CFI. FSA was used as the dependent variable and the independent variables that may be related to it were included for multiple linear regression analysis.@*RESULTS@#Based on CT image measurement, preoperative FNA was (15.96±10.01)°, FRA (3.36±10.87)°, AA (12.94±8.83)°, CA (28.9±12.6)°, postoperative FSA (16.18±11.01)°, and postoperative change in femoral anteversion angle was (0.22±9.98)°. Based on preoperative X-ray films measurements, the CTI was 0.586±0.081; the CFI was 4.135±1.125, with 23 hips classified as champagne cup type, 68 hips as normal type, and 12 hips as chimney type in the proximal femoral medullary cavity anatomy; NSA was (132.87±7.83)°; FO was (40.53±10.11) mm. There was no significant difference between preoperative FNA and postoperative FSA ( t=-0.227, P=0.821). Pearson correlation analysis showed that postoperative FSA was positively correlated with preoperative FNA, preoperative CA, postoperative change in femoral anteversion angle, and age ( P<0.05), while negatively correlated with preoperative FRA ( P<0.05). The postoperative change in femoral anteversion angle were positively correlated with preoperative FRA and postoperative FSA ( P<0.05), and negatively correlated with preoperative CA and FNA ( P<0.05). One-way ANOVA analysis showed that the above two indicators were not correlated with diagnosis and the proximal femoral medullary cavity anatomy type ( P>0.05). Multiple linear regression analysis showed a linear correlation between FSA and FNA, CA, age, and FRA ( F=10.998, P<0.001), and the best fit model was FSA=0.48×FNA-2.551.@*CONCLUSION@#The factors related to FSA after THA include patient's age, preoperative FNA, CA, FRA and postoperative femoral anteversion, of which preoperative FNA is the most closely related. When designing a surgical plan before surgery, attention should be paid to the patient's preoperative FNA, and if necessary, CT around the hip joint should be scanned to gain a detailed understanding of the proximal femoral anatomical structure.

Ventana cortical anterior para extracción de vástago en revisión de artroplastia total de cadera: una alternativa a la osteotomía trocantérica extendida / Anterior cortical window for stem extraction in total hip arthroplasty revision: an alternative to extended trochanteric osteotomy

Total hip arthroplasty (THA) is a safe and effective procedure in patients with end-stage ostheoarthritis. In the last years the indication for THA is increasingly in younger patients, associated with rising of life expectancy, this imply an increase in revision surgeries for various causes such as: aseptic loosening, fractures and infections. In this context and in view of the need to replace the femoral component, alternatives to the classic extended trochanteric osteotomy (ETO) arise, such as the anterior cortical window (ACW), which allows the rate of complications to be reduced with excellent results. We present the case of a 51-year-old patient who sustained one episode of dislocation, who required revision surgery due to aseptic loosenig, where the ACW was used for the extraction of the stem. In addition, a review of the literature was made to show advantages and complications regarding ETO.

Porous Lattice Structure of Femoral Stem for Total Hip Arthroplasty / Estructura de Diseño Poroso por Latice de Vástago Femoral para Artroplastia Total de Cadera

Abstract Total Hip Arthroplasty (THA) is one of the surgical procedures carried out satisfactorily in procedures for osteoarthritis and trauma lesions. ATC surgery reduces pain and improves the quality of life of young patients. Therefore, it is of great importance to improve the properties of hip implants, since current implants do not match their lifespan with the life expectancy of a young patient. This is because the solid prostheses that currently exist have a higher Young's modulus, and therefore are too rigid compared to the bone tissue. On the other hand, the cyclic and continuous loads to which the hip joint is subjected in daily activities, can cause loosening and consequent implant loss The present work proposes an implant manufactured with a porous lattice structure, which aims to reduce stiffness, allow bone growth and a more effective mechanical load transfer. Three computational models subjected to static charges were evaluated and compared: 1) healthy femur, 2) implanted femur with a commercial prosthesis, and 3) implanted femur with a prosthesis with lattice structure. For the computational analysis it was decided to perform a static analysis of a person standing on the left foot; a load equivalent to the body weight was applied on the head of the femur, balancing the reaction forces in the system of forces (contact force, body weight, and abductor muscle).. The results were shown in terms of displacement, compression and deformation. The model implanted with a prosthesis with a lattice design presented a slight decrease in displacement, and a decrease in compression and deformation values, which indicated that the proposed design has a better distribution and transport of the loads through its structure.

Resumen La artroplastia total de cadera (ATC) es uno de los tratamientos quirúrgicos llevados a cabo de manera satisfactoria en procedimientos para la osteoartritis y lesiones de trauma. La ATC reduce el dolor y mejora la calidad de vida de los pacientes. Por lo tanto, es de gran importancia mejorar las propiedades de los implantes de cadera, ya que los implantes actuales tienen un tiempo de vida útil y deben cumplir con las expectativas de rehabilitación para los pacientes. Esto se debe a que las prótesis sólidas que existen actualmente tienen un módulo de Young más elevado, y por lo tanto son demasiado rígidas a comparación del tejido óseo. Por otro lado, las cargas cíclicas y continuas a las que se ve sometida la articulación de la cadera en actividades diarias, pueden ser causa del aflojamiento y consecuente pérdida del implante. El presente trabajo propone un implante fabricado con una estructura porosa tipo látice, el cual tiene como objetivos reducir la rigidez, permitir crecimiento óseo y una transferencia de cargas mecánicas más efectiva. Se evaluaron y compararon tres modelos computacionales sometidos a cargas estáticas: 1) fémur sano, 2) fémur implantado con una prótesis comercial, y 3) fémur implantado con una prótesis con estructura látice. Para el modelo computacional se optó por hacer un análisis estático de una persona parada sobre el pie izquierdo; donde se aplicó una carga equivalente del peso corporal sobre la cabeza del fémur, equilibrando las fuerzas de reacción en el sistema de fuerzas (fuerza de contacto, peso corporal, y músculo abductor). Los resultados fueron mostrados en términos de desplazamiento, compresión y deformación. El modelo implantado con una prótesis con un diseño tipo látice presentó una ligera disminución de desplazamiento, y disminución en los valores de compresión y deformación, lo que indicó que el diseño propuesto posee una mejor distribución y transporte de las cargas a través de su estructura.

Bone remodeling after total hip arthroplasty with anatomic medullary locking prosthesis and its long-term effectiveness / 中国修复重建外科杂志

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.

Mid- and long-term effectiveness of total hip arthroplasty with Ribbed femoral stem prosthesis in 354 cases / 中国修复重建外科杂志

Objective: To evaluate the mid- and long-term effectiveness of total hip arthroplasty (THA) with Ribbed femoral stem prosthesis. Methods: A clinical data of 354 patients (384 hips) with hip disease who underwent THA with Ribbed femoral stem prostheses between October 2006 and May 2016 was retrospectively analyzed. There were 171 males and 183 females, with an average age of 53.4 years (range, 20-82 years). There were 324 cases of single hip and 30 cases of bilateral hips. The cause of THA included the avascular necrosis of the femoral head in 151 cases (159 hips), hip osteoarthritis in 134 cases (136 hips), rheumatoid arthritis in 43 cases (43 hips), ankylosing spondylitis in 20 cases (40 hips), and trauma in 6 cases (6 hips). The Harris score of total 354 patients before operation was 42.34±8.89. Harris scores were used to evaluate hip function after operation. X-ray films were used to determine the length of the lower limb, the radiolucent line on the femur side, the stability of the prosthesis, and the occurrence of stress shielding. Results: The incisions healed by first intention. All patients were followed up 2-11 years with an average of 7.4 years. The Harris score at last follow-up was 80.52±7.61, which significantly increased when compared with preoperative score ( t=134.804, P=0.000). Two cases (2 hips) of prosthetic infections, 3 cases (3 hips) of prothesis loosening, and 4 cases (4 hips) of periprosthetic fractures, and 48 cases (48 hips) of mild to moderate thigh pain occurred after operation. X-ray films showed 76 cases (78 hips) with radiolucent lines on the femur side and stress shielding. According to the Engh's method, there were 364 hips of bone ingrowth, 15 hips of fibrosis ingrowth, and 5 hips of prosthesis instability. The femoral stem subsidence occurred in 25 cases (25 hips), and the difference in leg length discrepancy was more than 10 mm in 5 patients. Conclusion: THA with Ribbed femoral stem prosthesis can achieve satisfactory effectiveness with good initial stability and rapid bone growth. The incidence of stress shielding is relatively high, but the stress shielding has no significant impact on the mid- and long-term survival rate and effectiveness of femoral prosthesis.

Morphological Feature of the Fitting Curves of Proximal Femoral Canal in Adults with Developmental Dysplasia of the Hip / 医用生物力学

Objective To measure and investigate the anatomical characteristics of the proximal femur canal curves in patients with developmental dysplasia of the hip (DDH), and to provide references for the design of femoral stem of DDH patients. Methods Three-dimensional reconstructions of the proximal femur were conducted from the CT data, and the anatomical morphology characteristics were obtained from 64 patients with DDH (74 hips, 12 males, 52 females, average age of 45.3 years) and 30 healthy controls (30 hips, 21 males, 9 females, average age of 29.4 years). Multiple anteroposterior diameter and mediolateral diameter around the lesser trochanter at different heights and the fitting curves of different groups were obtained. Results The femoral neck anteversion angle, neck-shaft angle, height of the isthmus, canal flare index (CFI), femoral head diameter and femoral offset of DDH patients and healthy controls were 26.39°±14.74° and 15.68°±7.95°, 125.65°±5.73° and 129.19°±5.80°, (99.14±14.62) mm and (110.13±11.73) mm, 3.63±0.77 and 4.45±0.79, (44.01±5.75) mm and (47.26±3.94) mm, (31.80±3.82) mm and (36.42±4.84) mm, respectively. DDH group had the significantly greater femoral neck anteversion angle, and other anatomical morphology characteristics were significantly smaller than the control group. The obtained anteroposterior diameter, mediolateral diameter and the fitting curves showed that DDH group had narrow medullary cavity and forward shifting anteroposterior diameter. In addition, there was a statistical significance between the Crowe Ⅳ DDH and other types of DDH, and deformation degree of the femur increased with the increase of DDH type. Conclusions The proximal femur of DDH patients was significantly different from the healthy controls. Moreover, there were significantly morphological differences between different types of DDH. The research findings can be used as quantitative references for understanding the morphological feature of DDH patients and the corresponding design of femoral stem for DDH patients.

Morphological Feature of the Fitting Curves of Proximal Femoral Canal in Adults with Developmental Dysplasia of the Hip / 医用生物力学

Objective To measure and investigate the anatomical characteristics of the proximal femur canal curves in patients with developmental dysplasia of the hip (DDH), and to provide references for the design of femoral stem of DDH patients. Methods Three-dimensional reconstructions of the proximal femur were conducted from the CT data, and the anatomical morphology characteristics were obtained from 64 patients with DDH (74 hips, 12 males, 52 females, average age of 45.3 years) and 30 healthy controls (30 hips, 21 males, 9 females, average age of 29.4 years). Multiple anteroposterior diameter and mediolateral diameter around the lesser trochanter at different heights and the fitting curves of different groups were obtained. Results The femoral neck anteversion angle, neck-shaft angle, height of the isthmus, canal flare index (CFI), femoral head diameter and femoral offset of DDH patients and healthy controls were 26.39°±14.74° and 15.68°±7.95°, 125.65°±5.73° and 129.19°±5.80°, (99.14±14.62) mm and (110.13±11.73) mm, 3.63±0.77 and 4.45±0.79, (44.01±5.75) mm and (47.26±3.94) mm, (31.80±3.82) mm and (36.42±4.84) mm, respectively. DDH group had the significantly greater femoral neck anteversion angle, and other anatomical morphology characteristics were significantly smaller than the control group. The obtained anteroposterior diameter, mediolateral diameter and the fitting curves showed that DDH group had narrow medullary cavity and forward shifting anteroposterior diameter. In addition, there was a statistical significance between the Crowe Ⅳ DDH and other types of DDH, and deformation degree of the femur increased with the increase of DDH type. Conclusions The proximal femur of DDH patients was significantly different from the healthy controls. Moreover, there were significantly morphological differences between different types of DDH. The research findings can be used as quantitative references for understanding the morphological feature of DDH patients and the corresponding design of femoral stem for DDH patients.

Clinical and Radiological Outcomes of Rectangular Tapered Cementless Stem According to Proximal Femoral Geometry in Elderly Asian Patients / 대한고관절학회지

PURPOSE: A retrospective analysis of mid- to long-term clinical and radiological outcomes of Korean patients over 60 years of age who underwent hip arthroplasty using a cementless rectangular tapered stem according to Dorr proximal femur geography. MATERIALS AND METHODS: From January 2007 to December 2013, 107 patients (112 hips) underwent hip arthroplasty using the C2 stem. The mean age of patients was 77.4 years (range, 60–91 years) and the mean follow-up duration was 91.1 months (range, 60–116 months). All patients were evaluated clinically and radiologically with special attention to Dorr femoral bone classification, implant fixation, radiolucent line (RLL), and thigh pain. RESULTS: All implants demonstrated radiographic evidence of stable fixation by bone ingrowth without any change in position. The mean Harris hip score improved from 65.5±16.0 (preoperative) to 90.5±15.9 (final follow-up) (P<0.001). Incidence of RLLs, stress shielding, and thigh pain was highest in patients with Dorr type A (RLL, P=0.021; stress shielding, P=0.030; thigh pain, P<0.001). One stem revision was performed due to deep infection. The Kaplan–Meier survival rate of the femoral stem was 97.6%. CONCLUSION: The overall survival rate of the C2 stems was greater than 97%; there were no significant differences in survival of the C2 stem according to the Dorr classification. The incidences of RLL of thigh pain and RLL were significantly different among Dorr classifications and (highest in patients with Dorr type A).

Total Hip Arthroplasty: Past, Present, and Future. What Has Been Achieved? / 대한고관절학회지

In the 1960s, Sir John Charnley introduced to clinical practice his concept of low-friction total hip arthroplasty (THA). Although early designs were plagued by poor performance and even failure, there have been steady advances in implant designs, biomaterials, surgical techniques and an understanding of the biomechanical restoration of the hip; these advances have contributed to improvements in implant survival and clinical outcomes of THA in the past three decades. With improved wear resistance and mechanical reliability, a potential to last for at least 25 to 30 years are now available for THA. In this review, we focus on the evolution of THA and review current controversies and future directions of this procedure based on a single surgeon's 29-year of experience at a single institution.

Total Hip Arthroplasty in Patients with Avascular Necrosis of the Entire Femur / 대한정형외과학회잡지

Avascular necrosis (AVN) is defined as the cellular death of bone and bone marrow components due to the loss of blood supply, and associated with post-traumatic or non-traumatic events. AVN usually involves the epiphysis of a long bone, such as the femoral and humeral heads, which are susceptible to osteonecrosis. Many studies have been conducted but they were restricted to investigations of femoral head avascular necrosis. The presence of osteonecrosis in the proximal femur may impair biological fixation after total hip arthroplasty. We report a 56-year-old male patient with avascular necrosis located not only at the femoral head, but also in the entire femur, including the medullary cavity, who underwent total hip arthroplasty 2 years earlier along with a review of the relevant literature.

Comparison of the Outcomes after Primary Total Hip Arthroplasty Using a Short Stem between the Modified Anterolateral Approach and Direct Anterior Approach with a Standard Operation Table / 대한정형외과학회잡지

PURPOSE: Total hip arthroplasty was performed using a direct anterior approach (DAA) on an ordinary operation table and a short femoral stem. The clinical radiographic results were evaluated by a comparison with those performed using the modified hardinge (anterolateral approach, ALA) method. MATERIALS AND METHODS: From January 2013 to November 2015, 102 patients who underwent total hip arthroplasty using DAA (DAA group) and the same number of patients using ALA (ALA group), both performed by a single surgeon, were compared and analyzed retrospectively. The operation time and amounts of bleeding were compared, and the improvement in post-operative pain, ambulatory capacity and functional recovery of the hip joint were checked. The location of insertion of the acetabular cup and femoral stem were evaluated radiologically, and the complications that occurred in the two groups were investigated. RESULTS: The amount of bleeding was significantly smaller in the DAA group (p=0.018). Up to 3 weeks postoperatively, recovery of hip muscle strength was significantly higher in the DAA group (flexion/extension strength p=0.023, abduction strength p=0.031). The Harris hip score was significantly better in the DAA group for up to 3 months (p<0.001) and the Koval score showed significantly better results in the DAA group up to 6 weeks (p≤0.001). The visual analogue scale score improvement was significantly higher in the DAA group by day 7 (p=0.035). The inclination angle (p<0.001) and anteversion angle (p<0.001) of the acetabular cup were located in the safe zone of the DAA group more than in the ALA group, and there was no statistically significant difference in the position of the femur stem and leg length difference. During surgery, two cases of greater trochanter fracture occurred in the DAA group (p=0.155). CONCLUSION: The DAA performed in the ordinary operation table using a short femoral stem showed post-operative early functional recovery. Because a simple to use fluoroscope was used during surgery with an anatomical position familiar to the surgeon, it is considered to be useful for the insertion of implants into the desired position and for an approach that is useful for the prevention of leg length differences.

Long-term Outcomes of Cemented Total Hip Arthroplasty in Patients with Ankylosing Spondylitis at a Minimum Follow-up of 10 Years / 대한고관절학회지

PURPOSE: This study was performed to evaluate long-term clinical and radiologic outcomes of cemented total hip arthroplasty in patients with ankylosing spondylitis. MATERIALS AND METHODS: A retrospective study of 12 patients (16 cases) diagnosed with ankylosing spondylitis undergoing total hip arthroplasty with cemented femoral stem from November 2002 to January 2006 with a minimum follow up of 10 years. Clinical outcomes were assessed using Harris Hip Scores and measures of pain and range of motion. Radiologic outcomes were assessed with serial plain X-ray. Fixation and stability of implant, enthesopathy of ischium and development of heterotopic ossification were also evaluated. RESULTS: Mean Harris Hip Scores significantly improved from pre-operative levels (58 points; range, 39–81 points) to post-operative (92 points; range, 68–100 points). Mean flexion contracture levels decreased from preoperative (13°) to post-operative (5°), and mean post-operative range of motion improved 106° compared to preoperative levels. No newly developed osteolysis lesions or implant loosening were observed in last follow up X-rays. One heterotopic ossification and one greater trochanter fracture were observed. Greater trochanter fracture was treated conservatively, and was resulted in bony union. No patients underwent revisions. CONCLUSION: This study revealed positive long-term clinical and radiologic outcomes following total hip arthroplasty with cemented femoral stems in patients with ankylosing spondylitis patients.

Utilización de tallos femorales porosos extendidos en revisiones de cadera / Use of extensively porous femoral stem in revision hip arthroplasty

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

Tres roturas sucesivas de los vástagos protésicos de cadera implantados en una paciente / Three successive fractures of different hip femoral stems on the same patient

Resumen: Se presenta el caso clínico de una paciente de 80 años que sufrió tres roturas de vástagos protésicos no cementados implantados en su cadera derecha en un período de tres años. Una rotura ocurrió en el cuello protésico y las otras dos en la unión de la porción cónica y cilíndrica del vástago, coincidiendo con la zona metafiso-diafisaria del fémur. La causas principales del fallo han sido un incremento de la concentración de fuerzas a nivel del implante como consecuencia del aumento de la longitud del cuello y de la lateralización femoral (offset). Se analizan otras causas que han podido contribuir a dicho fallo protésico.

Abstract: The clinical case of an 80-year-old female who suffered three fractures in uncemented stems implanted in her right hip in a period of three years is presented. A fracture occurred in the prosthetic neck and the other two at the juncture of the conical and cylindrical stem portion, coinciding with the metaphyseal-diaphyseal junction of the femur. The main causes of the failure were an increasing concentration of forces at the level of the implant as a consequence of the increased length of the neck and lateralization of the femur (offset). Other causes that have contributed to this prosthetic failure are analyzed.

Three dimensional morphometry of proximal femur to design best-fit Femoral stem for Indonesian population / Morfometría tridimensional del fémur proximal para diseñar prótesis a medida en la población de indonesa

To design custom-made prosthesis in a certain population, the morphometry needs to be measured. The results of this study were expected to provide basic data to design the ideal size of the total hip arthoplasty prosthesis for Indonesian population. This was an anthropometric study conducted on sex matched 100 healthy Indonesian mongoloid race subjects based on Computer Tomographic (CT) imaging on the proximal femur. The parameters being used in this study were Femoral Head Offset (FHO), Femoral Head Position (FHP), Femoral Head Diameter (FHD), Neck-Shaft Angle (NSA), Anteroposterior Width (APW) and Mediolateral Width at 3 different locations, and Canal Flare Index (CFI). This study showed that Indonesian has smaller proximal femur morphometry as compared to Western population. The mean value of all parameters in male were larger than female. Moreover, FHO and FHP showed significant difference among male and female indicating the location of male femoral head center lies superiorly as compared to female. The dimension of femoral canal was found to be mediolaterally oval, 1.43, 1.28, and 1,34, respectively, in 3 different cutting (20 mm above and 40 mm below lesser trochanter, and isthmus). CFI of Indonesian was classified to be stovepipe femoral canal (2.99) that is the suggestion to use cemented femoral stem. This study showed that Indonesian proximal femur dimension has smaller build compared with Western counterpart. The proposed dimensions can be used as the basic data to design the ideal size of the femoral stem for Indonesian population.

Para diseñar prótesis a medida en una población determinada, la morfometría necesita ser conocida. El objetivo de este estudio fue obtener resultados que sean útiles en la investigación para diseñar el tamaño ideal de una prótesis total de artroplastía de cadera para la población de Indonesia. Fue realizado un estudio antropométrico en 100 sujetos sanos de raza mongoloide de Indonesia, en los que se estudió la parte proximal del fémur por tomografía computadorizada (TC). Se consideraron como parámetros la cabeza del fémur (CF), posición de la cabeza del fémur (PCF), diámetro de la cabeza del fémur (DCF), ángulo cérvicodiafisario (ACD), ancho anteroposterior (AAP) y ancho-lateral en 3 lugares diferentes. La población Indonesia tiene una morfometría menor del fémur proximal en comparación con la población occidental. El valor medio de todos los parámetros en hombres fueron mayores a las mujeres. Por otra parte, CF y PCF mostraron diferencia significativa entre hombres y mujeres e indicó una ubicación superior del centro de la cabeza del fémur en hombres, en comparación con las mujeres. Se encontró que la dimensión del canal femoral fue mediolateral oval, 1,43, 1,28, y 1,34, en 3 cortes diferentes, respectivamente (20 mm superior y 40 mm inferior del trocánter menor e istmo). La dimensión del fémur proximal en la población de Indonesia es de menor tamaño en comparación con la contraparte occidental. Las dimensiones propuestas se pueden utilizar como datos básicos para el diseño de un tamaño ideal de vástago femoral para la población Indonesia.

The Short-term Clinical Outcome of Total Hip Arthroplasty Using Short Metaphyseal Loading Femoral Stem / 대한고관절학회지

PURPOSE: The purpose of this study was to retrospectively evaluate the short-term clinical and radiological outcomes of total hip arthroplasty (THA) with short metaphyseal loading femoral stem. MATERIALS AND METHODS: We retrospectively reviewed the records of 56 cases in 47 patients who had undergone THA with short metaphyseal loading femoral stem from April 2010 to December 2011. There were 20 males and 27 females. The mean age was 54 years (range, 26-77 years). The average follow up period was 4.6 years. Clinical results were evaluated by Harris hip scores (HHS) before the operation and at the last follow-up. Radiographic analysis was done by evaluating osteolysis, loosening, stress shielding, and alignement. RESULTS: The mean HHS significantly improved from 45 (range, 15-58) preoperatively to 98 (range, 85-100) at the last follow-up. In radiographic analyses, there was no evidence of osteolysis or loosening around the stems and the acetabuluar components. All cases showed rounding off of the calcar, grade 1 bone resorption of the proximal femur. With regard to implant alignment, 51 femoral component (91.1%) were in neutral position, and 5 (8.9%) were in varus position. There was 1 intraoperative fracture treated by cerclage wiring and no case was revised during follow-up period. CONCLUSION: Although longer follow-up is needed to confirm the durability of the short metaphyseal loading femoral stem, this short stem might provide stable fixation without diaphyseal fixation and demonstrated good clinical result at mean 4.6 year short term follow-up.

Revisiones de cadera en defectos óseos femorales Paprosky II y IIIA. Utilización de prótesis no cementada, modular, de fijación proximal y anclaje distal / Revision total hip arthroplasty in Paprosky II and IIIA femoral bone defects. Use of modular uncemented stems with proximal fixation

Introducción: El objetivo de este estudio retrospectivo fue observar el comportamiento de un tallo modular de fijación proximal y anclaje distal en revisiones de cadera con defectos femorales II y IIIA (Paprosky), evaluando la estabilidad protésica y articular, la restauración del offset y la diferencia de longitud. Materiales y Métodos: Se analizaron 22 revisiones de reemplazos totales de cadera. Doce mujeres y 10 hombres (edad promedio 62.38 años). El seguimiento promedio fue de 62 meses. El tallo femoral utilizado fue S-ROM® (Depuy, Johnson & Johnson). Los defectos óseos femorales fueron 15 de tipo II y 7 de tipo IIIA de Paprosky. Para la evaluación clínica se utilizó el puntaje de cadera de Harris. En las radiografías, se analizó el comportamiento del tallo, su integración, la diferencia de longitud y el offset femoral, y se consideró correcta una diferencia <5 mm. Resultados: El offset fue restaurado en 16 (72,3%) casos y la longitud de miembros se restauró en 15 (68,2%). Hubo un solo hundimiento del tallo, y de acuerdo con la clasificación de Engh, se observaron 17 (77,27%) uniones óseas. Se produjeron siete (31,8%) complicaciones, dos luxaciones que requirieron revisión, cuatro fracturas intraoperatorias y una paresia de ciático poplíteo externo. Conclusiones: Este tallo impresiona ser una alternativa válida para resolver un problema complejo. Por su versatilidad, permite resolver mecánicamente el defecto óseo, devuelve la longitud al miembro y el offset a la articulación, con un índice de complicaciones aceptables.

Background: The purpose of this retrospective analysis was to observe the outcomes of a modular hip system in revision total hip arthroplasty with Paprosky types II and IIIA femoral bone defects, evaluating their performance, offset restoration and leg length discrepancy correction. Methods: Twenty-two revision total hip arthroplasties were analyzed in 12 women and 10 men (average age 62.38 years). The average follow-up was 62 months. Femoral stems S-ROM® (Depuy, Johnson & Johnson) were used. Paprosky femoral bone deficit were 15 types II and 7 IIIA. Clinical evaluation was performed using the Harris Hip Score, while Engh lassification was used for stem fixation. Offset restoration, leg length discrepancy (a difference <5 mm was considered correct) and hip stability were evaluated radiographically. Results: Offset was properly restored in 16 (72.3%) cases and the leg length was matched in 15 (68.2%). There was a single stem subsidence and according to Engh classification, proximal bone ingrowth fixation was obtained in 17 (77.27%) patients. There were 7 (31.8%) complications: two dislocations that required revision, four intraoperative fractures and a lateral popliteal nerve paresis. Conclusions: S-ROM® modular system seems to be a valid alternative to solve a complex problem. Its versatility allows to optimize hip stability, leg length equalization and offset restoration in revision total hip arthroplasty, showing an acceptable complication rate.

Long-term Outcome of Polished Stems in Total Hip Arthroplasty / 대한고관절학회지

PURPOSE: The purpose of this study was to evaluate the clinical outcomes and radiologic findings of primary total hip arthroplasty (THA) using cemented polished femoral stems. MATERIALS AND METHODS: We retrospectively reviewed 91 hips (91 patients) that had undergone primary THA with cemented polished femoral stems who were followed for at least 10 years. The mean age at surgery was 57 years (47-75 years). Mean follow up period was 12.8 years (10.1-14.0 years). Harris Hip Score (HHS) was used for clinical evaluation. Radiologic evaluation was focused on cementing technique including subsidence within the cement mantle, radiolucent lines at the cement-bone or cement-stem interface, cortical hypertrophy, and calcar resorption. RESULTS: The average HHS was 55.2 points before the surgery that improved to an average of 93.2 points at the final follow-up. According to Barrack classification, there were 50, 32, and 9 cases in A, B, and C grades, respectively. Subsidence of femoral stem was less than 2 mm except in one patient. There were no progressing radiolucent line or loosening of the femoral stem. CONCLUSION: In this study, THA using cemented polished femoral stems was found to have favorable outcomes in long term follow-up.

Mid-term Results of Revision Total Hip Arthroplasty Using Modular Cementless Femoral Stems / 대한고관절학회지

PURPOSE: The purpose of this study was to evaluate the clinical and radiological results of revision total hip arthroplasty using modular distal fixation stems for proximal femoral deficiency. MATERIALS AND METHODS: Forty-five patients (47 hips) were analyzed more than 24 months after revision total hip arthroplasty that used modular distal fixation stems and was performed between 2006 and 2012. There were proximal femoral defects in all cases. Preoperative femoral defect classification revealed Paprosky type II in 31 cases, type IIIA in 7, and type IIIB in 9. The mean duration of follow-up was 53.4 (25-100) months. We evaluated the Harris hip score (HHS), walking ability according to Koval as clinical parameters, stem stability, and stem position change as radiographic parameters. Kaplan-Meier survival analysis was performed. RESULTS: The average HHS improved form 39.5 points to 91.3 points and walking ability also improved in most cases; all patients had stable fixation of the femoral stem. Postoperative complications included 5 cases of infection and 2 cases of dislocation. The survival rate with the end point of re-revision surgery due to infection or dislocation was 86% after 8-year follow-up. CONCLUSION: Cementless revision total hip arthroplasty using modular femoral stems is useful because the stems can be stably fixed on the diaphyseal portion of the femur, which has relatively good bone quality at mid-term follow-up.