RESUMEN
BACKGROUND: Radiostereometric analysis (RSA) is an established high precision tool enabling us to detect early implant migration in total hip arthroplasty. The aim of this study is to present the RSA and clinical results of a new cementless hip stem and to compare those with established benchmarks. METHODS: A total of 45 patients (46 hips) undergoing total hip arthroplasty were available for full radiographic and clinical assessment at 2 years post-operatively. Mean patient age was 69 (range 43-85) years and mean body mass index was 29 (range 21-38) kg/m2 . RSA was undertaken at day 1, 6 weeks, 6 months and 1 and 2 years post-operatively. Oxford hip score and EQ-5D-5L scores were recorded preoperatively and at the same other time points. Results were compared to published data of established implants. RESULTS: At 2 years, mean subsidence and retroversion were 0.61 mm (standard deviation 0.7 mm, range -0.19 to 3.06 mm) and 0.44° (standard deviation 0.81°, range 0.98 to 3.29°), respectively. Stem migration occurred primarily in the first 6 weeks with no detectable subsidence or rotation at 6 months or 2 years. Mean Oxford hip score and EQ-5D-5L improved from 18.6 to 44.7, and 69 to 86, respectively. There was one cup-only revision and no revisions for stem loosening. CONCLUSION: RSA serves as an accurate measure of femoral stem stability early in the post-operative period. Our data confirm that stability occurs as early as 6 weeks and is sustained at 2 years. The Paragon stem demonstrates stability parameters at 2 years that exceed other established benchmark implants.
Asunto(s)
Artroplastia de Reemplazo de Cadera , Prótesis de Cadera , Adulto , Anciano , Anciano de 80 o más Años , Artroplastia de Reemplazo de Cadera/efectos adversos , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Diseño de Prótesis , Falla de Prótesis , Análisis Radioestereométrico , Resultado del TratamientoRESUMEN
BACKGROUND: Accurate alignment is a basic principle of TKA surgery, but achieving alignment within this target may not translate into superior outcomes after surgery. PURPOSE: To assess if neutral TKA mechanical alignment was associated with superior knee outcomes and to examine the effect of various aspects of pre-operative and post-operative alignment on knee function. METHODS: Analysis of a database of 444 TKA patients between June 2009 and October 2016. Knee outcomes (WOMAC, AKSS and knee range of motion) were collected before surgery and during follow-up at a minimum of six months. RESULTS: Analysis included 444 TKA patients (62% female, mean age 66â¯years, mean follow-up 23â¯months). Deformity varied from 21° varus (meanâ¯=â¯7.9, SDâ¯=â¯2.8) to 17° valgus deformity (meanâ¯=â¯7.7, SDâ¯=â¯2.8). Pre-operatively, 101 (23%) knees were in native neutral mechanical alignment, while 278 (63%) were in varus and 65 (15%) were in valgus. Post-operatively, a group of 365 (82%) TKA were found to be in neutral mechanical alignment and a group of 79 (18%) TKA were noted to be 'Outliers' (17 [4%] TKAâ¯>â¯3° varus and 62 [14%] TKAâ¯>â¯3° valgus alignment). Restoration of the target of alignment of 0⯱â¯3° or 0⯱â¯1°, did not have better functional outcomes scores, range of motion or prosthesis longevity than those in the outlier range. CONCLUSION: Neutral TKA alignment did not appear to be a significant contributing factor to the improvement in knee function in short-medium term follow-up.
Asunto(s)
Artroplastia de Reemplazo de Rodilla , Articulación de la Rodilla/diagnóstico por imagen , Articulación de la Rodilla/cirugía , Medición de Resultados Informados por el Paciente , Satisfacción del Paciente , Rango del Movimiento Articular , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Estudios de Seguimiento , Humanos , Imagen por Resonancia Magnética , Masculino , Persona de Mediana Edad , Osteoartritis de la Rodilla/cirugía , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: The Stryker Anatomique Benoist Girard (ABG) hip implant system was a commonly used cementless prosthesis in the early 2000s, which fell from favour after several studies emerged implicating the prosthesis in high rates of revision. This retrospective, single-surgeon clinical study examines the fracture rate, revision rate and reasons for revision in 500 consecutive ABG II primary total conventional hip replacements. METHODS: Follow-up was conducted by audit of patient notes, patient mailout survey, patient phone contact and audit of the Australian National Joint Replacement Registry (NJRR) database to find instances of fracture and revision. End points were periprosthetic fracture and revision for any reason. RESULTS: Follow-up was 1.2-13.8 years with a mean of 6.58 years. Of the 500 hips, 17 (3.4%) had undergone a revision. Of these, 13 were due to periprosthetic fracture. Four further fractures occurred that were not revised. Eight of these periprosthetic fractures occurred within 1 year post-operatively. There were four revisions for recurrent dislocations. Kaplan-Meier survival curve demonstrates a 93.7% survivorship at 6.58 years for revision for any reason. Multivariate analysis showed the only statistically significant factor for increased risk of revision was smaller stem size. CONCLUSION: Our results were consistent with the literature in that the ABG II system has good medium-term results but is prone to periprosthetic fractures, especially in the early post-operative period. When used as a primary total hip arthroplasty, the ABG II system has an 8-year revision rate of 5.6% compared with the 4.9% of all primary total hip arthroplasties.
Asunto(s)
Artroplastia de Reemplazo de Cadera/instrumentación , Fracturas de Cadera/etiología , Prótesis de Cadera/efectos adversos , Fracturas Periprotésicas/etiología , Falla de Prótesis , Adulto , Anciano , Anciano de 80 o más Años , Artroplastia de Reemplazo de Cadera/métodos , Femenino , Estudios de Seguimiento , Fracturas de Cadera/epidemiología , Fracturas de Cadera/cirugía , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Fracturas Periprotésicas/epidemiología , Fracturas Periprotésicas/cirugía , Falla de Prótesis/etiología , Reoperación/estadística & datos numéricos , Estudios RetrospectivosRESUMEN
BACKGROUND: The rotational alignment of the femoral component in total knee arthroplasty (TKA) is regarded as being one of the critical factors associated with its long-term success. Traditionally, the femoral component is aligned parallel to the transepicondylar axis (TEA), perpendicular to the Whiteside's line (WL) or at 3 degrees external rotation to the posterior condylar line (PCL). The aim of this study was to use magnetic resonance imaging (MRI) to evaluate the relationship between these anatomical axes used for femoral component rotation (TEA to WL and PCL to TEA) and identify if any of these relationships were influenced by age, sex or coronal axial deformity (mechanical axis). METHODS: Two hundred and sixty-five patients undergoing preoperative MRI for patient-specific jigs TKA were included in our study. The MRI data were then analysed via preoperative planning software, and values relating to WL, TEA, PCL and coronal axial alignment were generated. RESULTS: The mean age was 66.0 ± 8.7 years. There were 102 men and 163 women. The average mechanical axis (coronal deformity) was 4.2 ± 6.1 degrees of varus. TEA compared with WL was on average 92.6 ± 2.3 degrees. PCL was on average 2.3 ± 1.8 degrees internally rotated to the TEA. The PCL was more internally rotated in women (P < 0.01) and valgus (P < 0.001) knees. There was no significant relationship between age or varus knees when comparing TEA to WL (P > 0.1) and PCL to TEA (P > 0.1). CONCLUSIONS: Our study shows that the previously assumed values for rotational alignment of the femoral component may need to be reviewed. The use of advanced preoperative imaging (e.g. MRI) may aid to overcome this variability and assist surgeons in planning femoral component alignment in TKA.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/métodos , Fémur/anatomía & histología , Imagen por Resonancia Magnética/métodos , Osteoartritis de la Rodilla/cirugía , Anciano , Femenino , Fémur/cirugía , Estudios de Seguimiento , Humanos , Masculino , Osteoartritis de la Rodilla/diagnóstico , Estudios Retrospectivos , RotaciónRESUMEN
BACKGROUND: The failure to restore mechanical alignment and appropriate rotational axis intraoperatively has been described as one of the most common causes of implant failure in total knee arthroplasty (TKA). Both conventional and computer-assisted TKA have their limitations. Patient-specific jigs (PSJ) offer a possible alternative method for TKA. The aim of this study was to investigate if the use of PSJ offers reproducible and accurate orientation of the components in TKA compared with conventional and computer-assisted surgery. METHODS: We conducted a prospective case series looking at 261 consecutive patients undergoing TKA for osteoarthritis using the Signature Patient Specific System (Biomet, North Ryde, NSW, Australia). Each patient underwent a preoperative magnetic resonance imaging for planning. Using a computer software program, specialized femoral and tibial pin placement jigs were generated. Post-operative femoral and tibial component alignment was measured using computed tomography. RESULTS: Of patients, 96.2% achieved femoral rotational alignment ±3 degrees of the transepicondylar axis. Tibial coronal alignment showed 92.7% of cases were 90 ± 3 degrees to the tibial medullary axis. Implant measurements of the posterior tibial slope demonstrated 76.6% of cases were within our accepted 0 to 7 degrees slope and 81.2% of patients had an overall mechanical axis within ±3 degrees of neutral. We also recorded femoral coronal alignment of the last 98 patients of our group and found that 99% were within 90 ± 3 degrees. CONCLUSION: PSJ for TKA shows good accuracy in alignment when compared with conventional TKA. However, improvements in the development of the tibial alignment cutting guides will aid in further increasing its overall accuracy and reproducibility.