RESUMEN
In a patient with severe unicompartmental knee osteoarthritis where conservative treatments have been exhausted, with painful symptoms located on the affected side and with a reducible axis, the unicompartmental knee prosthesis (UKP) is the first option for our work group. Within the study to confirm the diagnosis and plan the surgery, weight-bearing knee x-rays, Rosenberg x-rays, and teleradiographs of the lower extremities stand out. The objective of surgery is to replace the affected area, restoring the anatomy with an adequate balance of soft tissues. Regarding alignment, the challenge is not to overload the opposite side or that of the prosthesis. There are mobile and fixed plates and although the clinical and survival results are similar, in recent years with the incorporation of robotic surgery, the balance has tipped towards the use of fixed plates. The clinical and functional results are better and there are fewer complications than when total knee prostheses (TKP) are used in the same type of patients. The survival studied in registries is lower than for TKP, but when used in high-flow centers where the percentage of UKP is close to a third of the total with strict patient selection, the duration is as good as in PTR.
En un paciente con artrosis unicompartimental de rodilla grave, donde se agotaron los tratamientos conservadores que tiene clínica dolorosa localizada en el lado afectado y con alteración del eje reductible, la prótesis unicompartimenal de rodilla (PUR) es la primera opción para nuestro grupo de trabajo. Dentro del estudio para confirmar el diagnóstico y planificar la cirugía destacan las radiografías de rodillas con carga, radiografía de Rosenberg y telerradiografías de extremidades inferiores. El objetivo de la cirugía es reemplazar la zona afectada, restituyendo la anatomía con un adecuado balance de partes blandas. Respecto al alineamiento el desafío es no sobrecargar el lado contrario ni tampoco el de la prótesis. Existen de platillo móvil y fijo y aunque los resultados clínicos y de supervivencia son semejantes, en los últimos años con la incorporación de la cirugía robótica, la balanza se ha inclinado para el uso de los platillos fijos. En pacientes con artrosis unicompartimental los resultados clínicos y funcionales son mejores con PUR y tiene menos complicaciones que cuando se usan prótesis totales (PTR). La supervivencia estudiada en registros es menor que para PTR, pero cuando se usa en centros de alto flujo en que el porcentaje de PUR es cercano a un tercio del total con una estricta selección de pacientes, la duración es tan buena como en la PTR.
Asunto(s)
Artroplastia de Reemplazo de Rodilla , Prótesis de la Rodilla , Osteoartritis de la Rodilla , Humanos , Resultado del Tratamiento , Estudios Retrospectivos , Artroplastia de Reemplazo de Rodilla/métodos , Osteoartritis de la Rodilla/cirugía , Articulación de la Rodilla/cirugía , Diseño de Prótesis , Falla de PrótesisRESUMEN
Resumen: En un paciente con artrosis unicompartimental de rodilla grave, donde se agotaron los tratamientos conservadores que tiene clínica dolorosa localizada en el lado afectado y con alteración del eje reductible, la prótesis unicompartimenal de rodilla (PUR) es la primera opción para nuestro grupo de trabajo. Dentro del estudio para confirmar el diagnóstico y planificar la cirugía destacan las radiografías de rodillas con carga, radiografía de Rosenberg y telerradiografías de extremidades inferiores. El objetivo de la cirugía es reemplazar la zona afectada, restituyendo la anatomía con un adecuado balance de partes blandas. Respecto al alineamiento el desafío es no sobrecargar el lado contrario ni tampoco el de la prótesis. Existen de platillo móvil y fijo y aunque los resultados clínicos y de supervivencia son semejantes, en los últimos años con la incorporación de la cirugía robótica, la balanza se ha inclinado para el uso de los platillos fijos. En pacientes con artrosis unicompartimental los resultados clínicos y funcionales son mejores con PUR y tiene menos complicaciones que cuando se usan prótesis totales (PTR). La supervivencia estudiada en registros es menor que para PTR, pero cuando se usa en centros de alto flujo en que el porcentaje de PUR es cercano a un tercio del total con una estricta selección de pacientes, la duración es tan buena como en la PTR.
Abstract: In a patient with severe unicompartmental knee osteoarthritis where conservative treatments have been exhausted, with painful symptoms located on the affected side and with a reducible axis, the unicompartmental knee prosthesis (UKP) is the first option for our work group. Within the study to confirm the diagnosis and plan the surgery, weight-bearing knee x-rays, Rosenberg x-rays, and teleradiographs of the lower extremities stand out. The objective of surgery is to replace the affected area, restoring the anatomy with an adequate balance of soft tissues. Regarding alignment, the challenge is not to overload the opposite side or that of the prosthesis. There are mobile and fixed plates and although the clinical and survival results are similar, in recent years with the incorporation of robotic surgery, the balance has tipped towards the use of fixed plates. The clinical and functional results are better and there are fewer complications than when total knee prostheses (TKP) are used in the same type of patients. The survival studied in registries is lower than for TKP, but when used in high-flow centers where the percentage of UKP is close to a third of the total with strict patient selection, the duration is as good as in PTR.
RESUMEN
BACKGROUND: The main reasons for revision of unicompartmental knee arthroplasty (UKA) are loosening, wear, extension of osteoarthritis to another compartment, and infection. There have been no studies of the management of infected UKA, whose incidence varies from 0.2% to 1%. Our objective was to describe infection-related and mechanical outcomes of chronic UKA infection managed by one-stage conversion to total knee arthroplasty (TKA). PATIENTS AND METHODS: Consecutive patients with chronic UKA infection managed by one-stage conversion to TKA between January 2003 and December 2010 were included in a retrospective single-center study. All patients also received appropriate dual antibiotic therapy intravenously for 6 weeks then orally for 6 additional weeks. RESULTS: During the study period, among 233 cases of infected knee arthroplasty managed at our center, 9 met the study inclusion criteria. The UKA was medial in 6 patients, lateral in 2, and patellofemoral in 1. Median age was 67 years (range, 36-83 years) and median infection duration was 9months. In 5 patients, previous treatment with synovectomy, joint lavage, and antibiotics had failed. The following bacteria were identified: oxacillin-susceptible Staphylococci, n=6 (S. epidermidis, n=4; S. capitis, n=1; and S. lugdunensis, n=1); nutritionally deficient Streptococcus, n=1; Enterococcus durans, n=1; and Escherichia coli, n=1. Median follow-up was 60 months (range, 36-96 months). No patient experienced recurrent infection or required revision surgery for infection. No medical complications limiting the use of appropriate antibiotic therapy were recorded. The mean preoperative knee and function scores were 60 and 50, respectively; corresponding mean postoperative values were 75 and 65, respectively. DISCUSSION: UKA infection involves both the prosthesis and the native cartilage, neither of which can be treated conservatively in chronic forms. After identification of the causative organism, synovectomy and joint excision followed by same-stage TKA and combined with appropriate antibiotic therapy for 3 months is effective. LEVEL OF EVIDENCE: IV, retrospective cohort study.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/métodos , Prótesis de la Rodilla/efectos adversos , Infecciones Relacionadas con Prótesis/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Antibacterianos/uso terapéutico , Estudios de Cohortes , Femenino , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , SinovectomíaRESUMEN
BACKGROUND: Since 2000, the Register of Prosthetic Orthopedic Implants (RIPO) has been following all hip, knee, and shoulder arthroplasties in the Emilia-Romagna region, comprising 4.5 million inhabitants, in northern Italy. The aim of the present analysis was to present the main figures of unicompartmental knee implants processed from the Registry. METHODS: During the period 2000-2011, 3929 unicompartmental knee arthroplasties were performed on 3645 resident patients, of which 71% were females. The medial condyle was treated in 94% of cases, where mean age at surgery was 67.3 years and mean body weight was 76.6 kg. The main outcome measure was time to revision of at least one single component. The Kaplan-Meier survival and Cox multivariate analyses have been applied. RESULTS: At 10-year follow-up, the percentage of survival was 86.8% (confidence interval (CI) at 95% was 84.1-89.5); total aseptic loosening represented 42% of the causes of failure, pain represented 15%, and sepsis represented 11%. Age at surgery significantly influences the survival of the prosthesis, whatever the reason for revision, while the type of tibial component (monoblock or metal tray) does not appear to be a determinant. Septic failure is not prevented by the use of antibiotic-loaded cement. CONCLUSION: Results are comparable to main orthopedic registries from Scandinavia, Australia, and New Zealand, even if some differences can be highlighted.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/estadística & datos numéricos , Prótesis de la Rodilla/estadística & datos numéricos , Sistema de Registros/estadística & datos numéricos , Factores de Edad , Anciano , Artroplastia de Reemplazo de Rodilla/métodos , Femenino , Humanos , Italia/epidemiología , Masculino , Dolor Postoperatorio/epidemiología , Falla de Prótesis , Sepsis/epidemiologíaRESUMEN
INTRODUCTION: Results of unicompartmental knee arthroplasty (UKA) revision are known but the severity of bone loss and the need for reconstruction are not detailed for different tibial implants. HYPOTHESIS: Metal-backing UKA revision exposes the patient to more severe tibial bone loss and requires more substantial reconstruction procedures than cemented polyethylene UKA revision. MATERIALS AND METHODS: This retrospective series of 23 revisions of UKA to total knee arthroplasty (TKA) compared 11 all-polyethylene UKAs with 12 metal-backing UKAs. Factors that contributed to failure were aseptic loosening (n=12) and osteoarthritis evolution (n=11). Both groups were similar regarding the demographic and clinical features. We reported bone loss and the reconstruction procedure to fill it according to the initially used tibial implant. The results were evaluated with the IKS score to a follow-up of 37 months (range, 24-67 months). RESULTS: There were more tibial segmental bone loss (10 versus 3) and more metal wedges (8/12 versus 2/11) in metal-backing UKA revision (P<0.05). Tibial stems were more often used in metal-backing UKA revision (12/12 versus 7/11) (P=0.04). The results of TKA at follow-up did not differ according to whether the revised tibial implant was all polyethylene (IKS=155 [range, 107-195]) or metal-back (IKS=155 [range, 127-172]). DISCUSSION: This study suggests that metal-backing UKA revision exposes the patient to more severe tibial bone loss requiring more substantial reconstruction. These results must be confirmed on a larger population, but surgeons should be alerted to this kind of revision surgery, which warrants having available a revision knee prothesis. LEVEL OF EVIDENCE: Level III, case-control study.
Asunto(s)
Artroplastia de Reemplazo de Rodilla/efectos adversos , Prótesis de la Rodilla , Osteoartritis de la Rodilla/cirugía , Osteoporosis/complicaciones , Falla de Prótesis/etiología , Anciano , Artroplastia de Reemplazo de Rodilla/métodos , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Humanos , Masculino , Metales , Persona de Mediana Edad , Osteoartritis de la Rodilla/diagnóstico por imagen , Osteoporosis/diagnóstico , Dimensión del Dolor , Polietileno , Diseño de Prótesis , Radiografía , Recuperación de la Función , Reoperación/métodos , Estudios Retrospectivos , Medición de Riesgo , Factores de Tiempo , Resultado del TratamientoRESUMEN
Unicompartmental knee arthroplasty (UKA) has evolved into a suitable option for diseased knees that cannot be managed with arthroscopic treatment and at the same time are not good candidates for total knee replacement. Since meticulous execution of the surgical technique is essential to optimizing UKA outcome, some procedural key-points are mandatory. Templates (phantoms) are then used to size the required prosthetic component (using these radiographs. Arthritic varus (or valgus) knees with an asymptomatic patello-femoral joint are typically ideal for UKA. Metal-backed tibial components should be favourite instead of all-polyethylene tibial components to avoid polyethylene creep that may occur in fixed bearings. Moreover, a proper thickness of the polyethylene layer is mandatory, in order to avoid early failure.