RESUMEN
The purpose was to determine if increasing serum 25(OH)D and calcium in postmenopausal women increased skeletal muscle size, strength, balance, and functional task performance while decreasing muscle fatigue. PCSA of the vastus lateralis increased and ascent of stairs time decreased after 6 months of increased serum 25(OH)D. PURPOSE: The Institute of Medicine recommends ≥ 20 ng/ml of serum 25-hydroxyvitamin D [25(OH)D] for bone and overall health. Serum 25(OH)D levels have been associated with physical performance, postural sway, and falls. The purpose of this study was to determine if increasing postmenopausal women's serum 25(OH)D levels from 20-30 ng/ml to 40-50 ng/ml improved skeletal muscle size, strength, balance, and functional performance while decreasing skeletal muscle fatigue. METHODS: Twenty-six post-menopausal women (60-85 years old) with baseline serum 25(OH)D levels between 20 and 30 ng/ml were recruited. Oral over-the-counter (OTC) vitamin D3 and calcium citrate were prescribed to increase subjects' serum 25(OH)D to levels between 40 and 50 ng/ml, serum calcium levels above 9.2 mg/dl, and PTH levels below 60 pg/ml, which were confirmed at 6 and 12 weeks. Outcome measures assessed at baseline and 6 months included muscle physiological cross-sectional area (PCSA), muscle strength, postural balance, time to perform functional tasks, and muscle fatigue. Repeated measures comparisons between baseline and follow-up were performed. RESULTS: Nineteen subjects completed the study. One individual could not afford the time commitment for the repeated measures. Three individuals did not take their vitamin D as recommended. Two subjects were lost to follow-up (lack of interest), and one did not achieve targeted serum 25(OH)D. Vastus lateralis PCSA increased (p = 0.007) and ascent of stair time decreased (p = 0.042) after 6 months of increasing serum 25(OH)D levels from 20-30 ng/ml to 40-50 ng/ml. Isometric strength was unchanged. Anterior-posterior center of pressure (COP) excursion and COP path length decreased (p < 0.1) albeit non-significantly, suggesting balance may improve from increased serum 25(OH)D and calcium citrate levels. CONCLUSIONS: Several measures of muscle structure and function were sensitive to elevated serum 25(OH)D and calcium levels indicating that further investigation of this phenomenon in post-menopausal women is warranted.
Asunto(s)
Citrato de Calcio/administración & dosificación , Calcio/sangre , Colecalciferol/administración & dosificación , Fatiga Muscular/efectos de los fármacos , Fuerza Muscular/efectos de los fármacos , Posmenopausia/sangre , Deficiencia de Vitamina D/prevención & control , Vitamina D/análogos & derivados , Absorciometría de Fotón/métodos , Anciano , Anciano de 80 o más Años , Conservadores de la Densidad Ósea/administración & dosificación , Conservadores de la Densidad Ósea/uso terapéutico , Citrato de Calcio/uso terapéutico , Colecalciferol/uso terapéutico , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Persona de Mediana Edad , Actividad Motora/efectos de los fármacos , Proyectos Piloto , Análisis y Desempeño de Tareas , Resultado del Tratamiento , Vitamina D/sangre , Deficiencia de Vitamina D/sangre , Deficiencia de Vitamina D/tratamiento farmacológico , Vitaminas/administración & dosificación , Vitaminas/uso terapéuticoRESUMEN
AIMS: Instability continues to be a troublesome complication after total hip arthroplasty (THA). Patient-related risk factors associated with a higher dislocation risk include the preoperative diagnosis, an age of 75 years or older, high body mass index (BMI), a history of alcohol abuse, and neurodegenerative diseases. The goal of this study was to assess the dislocation rate, radiographic outcomes, and complications of patients stratified as high-risk for dislocation who received a dual mobility (DM) bearing in a primary THA at a minimum follow-up of two years. MATERIALS AND METHODS: We performed a retrospective review of a consecutive series of DM THA performed between 2010 and 2014 at our institution (Hospital for Special Surgery, New York, New York) by a single, high-volume orthopaedic surgeon employing a single prosthesis design (Anatomic Dual Mobility (ADM) Stryker, Mahwah, New Jersey). Patient medical records and radiographs were reviewed to confirm the type of implant used, to identify any preoperative risk factors for dislocation, and any complications. Radiographic analysis was performed to assess for signs of osteolysis or remodelling of the acetabulum. RESULTS: There were 151 patients who met the classification of high-risk according to the inclusion criteria and received DM THA during the study period. Mean age was 82 years old (73 to 95) and 114 patients (77.5%) were female. Mean follow-up was 3.6 years (1.9 to 6.1), with five patients lost to follow-up and one patient who died (for a reason unrelated to the index procedure). One patient (0.66%) sustained an intraprosthetic dislocation; there were no other dislocations. CONCLUSION: At mid-term follow-up, the use of a DM bearing for primary THA in patients at high risk of dislocation provided a stable reconstruction option with excellent radiographic results. Longer follow-up is needed to confirm the durability of these reconstructions.
Asunto(s)
Artroplastia de Reemplazo de Cadera/instrumentación , Luxación de la Cadera/etiología , Prótesis de Cadera , Anciano , Anciano de 80 o más Años , Artroplastia de Reemplazo de Cadera/efectos adversos , Artroplastia de Reemplazo de Cadera/métodos , Femenino , Estudios de Seguimiento , Luxación de la Cadera/diagnóstico por imagen , Articulación de la Cadera/diagnóstico por imagen , Articulación de la Cadera/cirugía , Humanos , Inestabilidad de la Articulación/etiología , Masculino , Complicaciones Posoperatorias , Diseño de Prótesis , Falla de Prótesis , Radiografía , Reoperación/métodos , Estudios Retrospectivos , Factores de RiesgoRESUMEN
AIMS: The aim of this systematic review was to report the rate of dislocation following the use of dual mobility (DM) acetabular components in primary and revision total hip arthroplasty (THA). MATERIALS AND METHODS: A systematic review of the literature according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines was performed. A comprehensive search of Pubmed/Medline, Cochrane Library and Embase (Scopus) was conducted for English articles between January 1974 and March 2016 using various combinations of the keywords "dual mobility", "dual-mobility", "tripolar", "double-mobility", "double mobility", "hip", "cup", "socket". The following data were extracted by two investigators independently: demographics, whether the operation was a primary or revision THA, length of follow-up, the design of the components, diameter of the femoral head, and type of fixation of the acetabular component. RESULTS: In all, 59 articles met our inclusion criteria. These included a total of 17 908 THAs which were divided into two groups: studies dealing with DM components in primary THA and those dealing with these components in revision THA. The mean rate of dislocation was 0.9% in the primary THA group, and 3.0% in the revision THA group. The mean rate of intraprosthetic dislocation was 0.7% in primary and 1.3% in revision THAs. CONCLUSION: Based on the current data, the use of DM acetabular components are effective in minimising the risk of instability after both primary and revision THA. This benefit must be balanced against continuing concerns about the additional modularity, and the new mode of failure of intraprosthetic dislocation. Longer term studies are needed to assess the function of these newer materials compared with previous generations. Cite this article: Bone Joint J 2017;99-B(1 Supple A):18-24.
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Acetábulo/cirugía , Artroplastia de Reemplazo de Cadera/efectos adversos , Luxación de la Cadera/etiología , Prótesis de Cadera/efectos adversos , Artroplastia de Reemplazo de Cadera/métodos , Humanos , Diseño de Prótesis , Falla de Prótesis , Reoperación/efectos adversos , Reoperación/instrumentaciónRESUMEN
In this paper, we will consider the current role of simultaneous-bilateral TKA. Based on available evidence, it is our opinion that bilateral one stage TKR is a safe and efficacious treatment for patients with severe bilateral arthritic knee disease but should be reserved for selected patients without significant medical comorbidities.
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Artroplastia de Reemplazo de Rodilla/métodos , Osteoartritis de la Rodilla/cirugía , Artroplastia de Reemplazo de Rodilla/mortalidad , Humanos , Osteoartritis de la Rodilla/mortalidad , Selección de Paciente , Atención Perioperativa/métodos , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/prevención & control , Resultado del TratamientoRESUMEN
OBJECTIVE: C-reactive protein (CRP) has been associated with disease progression in patients with osteoarthritis (OA), but the reasons for this remain unclear. We hypothesized that higher CRP would be related to local inflammatory findings in the joints of patients with OA. METHODS: Plasma and synovial membrane specimens from 54 OA patients undergoing total hip or knee arthroplasty or arthroscopy were obtained. Synovial fluid was obtained from 25 of these patients. Hematoxylin and eosin stained synovial membrane sections were scored for degree of inflammatory cell infiltration. Plasma high-sensitivity CRP (hsCRP) levels, and serum and synovial fluid interleukin (IL)-6 and IL-1beta levels were measured by enzyme-linked immunosorbent assay. RESULTS: Fifty-seven percent of patients with idiopathic OA had inflammatory infiltrates within the synovial membrane. The mean hsCRP level in patients with inflammatory infiltrates was significantly higher than those without inflammation (4.7 +/- 5.0 mg/L vs 1.7 +/- 3.6 mg/L, P = 0.003). There were significant correlations between hsCRP levels and synovial fluid IL-6 (r = 0.64, P = 0.0006), degree of synovial inflammatory infiltration (r = 0.43, P = 0.002), and body mass index (r = 0.31, P = 0.02). Multivariate analysis indicated that only degree of inflammatory infiltrate was significantly associated with hsCRP level (P = 0.026). CONCLUSION: These results suggest that systemic hsCRP levels reflect synovial inflammation in OA patients, perhaps by means of synovial IL-6 production. Future studies are needed to clarify how these infiltrates and their products may contribute to disease pathogenesis.
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Proteína C-Reactiva/análisis , Interleucina-1beta/análisis , Interleucina-6/análisis , Osteoartritis de la Cadera/metabolismo , Osteoartritis de la Rodilla/metabolismo , Líquido Sinovial/química , Adulto , Anciano , Anciano de 80 o más Años , Artroplastia de Reemplazo de Cadera , Artroplastia de Reemplazo de Rodilla , Artroscopía , Estudios Transversales , Femenino , Humanos , Interleucina-1beta/sangre , Interleucina-6/sangre , Masculino , Persona de Mediana Edad , Osteoartritis de la Cadera/sangre , Osteoartritis de la Rodilla/sangreAsunto(s)
Artritis/historia , Artroplastia de Reemplazo de Rodilla/historia , Prótesis de la Rodilla/historia , Adulto , Anciano , Artritis/cirugía , Artroplastia de Reemplazo de Rodilla/métodos , Femenino , Historia del Siglo XX , Humanos , Articulación de la Rodilla/cirugía , Masculino , Persona de Mediana EdadRESUMEN
Postoperative ileus is a recognized complication of lower extremity surgery. In a review of 21,589 patients who underwent either total hip or total knee arthroplasty between 1988 and 1997, 0.32% developed postoperative ileus. The ileus lasted >3 days in 46% of patients. The purpose of this study was to investigate the risk factors associated with ileus during 3 days after total joint arthroplasty. The average age of the patients with prolonged ileus was 69.1 years, and 70% were male. The development of a prolonged ileus was associated significantly with younger age (P<.005) and male gender (P<.02). In total knee arthroplasty, more cases of postoperative ileus were seen in bilateral surgery. Patients who are younger, male, and undergoing bilateral total knee arthroplasty are at an increased risk of having a more prolonged postoperative ileus and should be monitored closely.
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Artroplastia de Reemplazo de Rodilla , Obstrucción Intestinal/epidemiología , Complicaciones Posoperatorias/epidemiología , Anciano , Distribución de Chi-Cuadrado , Femenino , Humanos , Modelos Lineales , Modelos Logísticos , Masculino , Persona de Mediana EdadRESUMEN
Compared with primary knee replacement, total knee arthroplasty revision surgery is a more complex procedure and accounts for greater expenditures of healthcare resources at each clinical stage. Overall, patients having revision procedures have poorer functional outcomes and higher complication rates than patients having primary arthroplasty. Despite the expanded scope of revision problems and the rapidly emerging technology in revision surgery, the long-term success of any method remains in question. Because there is little consensus on the timing of revision surgery, optimal surgical reconstruction, and the type of prosthesis to be implanted, the Knee Society began development of an Index of Severity for Failed Total Knee Arthroplasty. Fifty-four percent of Knee Society members completed an 82-item questionnaire that determined their clinical impression about potential risk factors for the outcomes of revision surgery for failed total knee replacements. Using these results, a consensus group developed the final version of the index. The result of the nominal group process was the Knee Society Index of Severity, which was based on eight distinct domains. Each domain was divided into attributes and weights based on the questionnaire responses and consensus meeting. Actual case scenarios from five institutions were used to test interrater reliability and validity. The interrater reliability of the average score of all ratings was 0.95; the correlation of the criterion rating with the mean rating was 0.77. When three outliers were not included, the Pearson product correlation increased to 0.92. These data support the application of the Knee Society Index of Severity as a critical component of risk factor studies, effectiveness research, and cost-effectiveness analysis involving revisions of total knee replacements.
Asunto(s)
Artroplastia de Reemplazo de Rodilla , Prótesis de la Rodilla , Falla de Prótesis , Índice de Severidad de la Enfermedad , Humanos , Reoperación , Reproducibilidad de los ResultadosRESUMEN
Previous classifications of severity for total knee arthroplasty revisions have been based largely on bone loss of the femur and tibia. These approaches failed to address the more technically difficult issues in revision surgery such as surgical exposure, contractures, extremity alignment, implant removal, soft tissue stability (in the anteroposterior and in the sagittal planes), extensor mechanism integrity, and patellar revisability. Through the Knee Society, the authors developed a severity index that incorporated these latter factors into one measure. The current authors describe the application of the Knee Society Index of Severity for failed total knee arthroplasty and its method of scoring.
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Prótesis de la Rodilla , Falla de Prótesis , Índice de Severidad de la Enfermedad , Artroplastia de Reemplazo de Rodilla , Humanos , Pronóstico , Reoperación , Factores de RiesgoRESUMEN
Deep venous thrombosis is the most common complication in patients having elective total knee replacement. Pneumatic compression devices play an important role in the prophylaxis of deep venous thrombosis and effectively decrease the risk of distal deep venous thrombosis. The combination therapy with pharmacologic agents has the benefit of decreasing the rate of proximal deep venous thrombosis and therefore is recommended. In the absence of clinical data, recent in vivo flow studies suggest that calf or combined foot and calf compression are superior to foot compression alone. Epidural anesthesia in comparison with general anesthesia decreases the incidence of thromboembolic disease after total knee arthroplasty. Although hypotensive anesthesia and intraoperative heparin have been proven to substantially lower the incidence of deep venous thrombosis after total hip arthroplasty, the current literature does not support its application during the implantation of a total knee replacement. Pneumatic compression devices are an important part of deep venous thrombosis prophylaxis especially in the early postoperative period considering that pharmacologic anticoagulation is contraindicated in the first 12 hours after spinal anesthesia and in the presence of an epidural line.
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Artroplastia de Reemplazo de Rodilla/efectos adversos , Trombosis de la Vena/prevención & control , Humanos , Pierna/irrigación sanguínea , Presión , Flujo Sanguíneo RegionalRESUMEN
BACKGROUND: There is little information in the literature regarding the outcome of total knee arthroplasty following open reduction and internal fixation of fractures of the tibial plateau. The goal of this study was to evaluate the results of such procedures after a minimum of five years of follow-up. METHODS: We retrospectively analyzed the outcomes of fifteen total knee arthroplasties performed at an average of 38.6 months (range, eight months to eleven years) after open reduction and internal fixation of a fracture of the tibial plateau in fifteen consecutive patients. The average duration of follow-up after the total knee arthroplasty procedures was 6.2 years (range, 5.4 to 11.1 years). The average age of the patients was fifty-six years (range, thirty-seven to sixty-eight years) at the time of the arthroplasty. We evaluated the outcomes on the basis of the Hospital for Special Surgery knee score, the Short Form-36 score, and radiographs of the knees. RESULTS: The average Hospital for Special Surgery knee score was 51 points (range, 20 to 74 points) before the arthroplasty, and it increased to 80 points (range, 44 to 91 points) postoperatively. Four knees were scored as excellent, eight had a good result, one was rated as fair, and two had a poor result. The average Short Form-36 scores were 58.0 points for general health, 72.4 points for bodily pain, 72.1 points for mental health, 58.3 points for physical functioning, 84.6 points for physical role functioning, 81.0 points for social functioning, and 57.7 points for vitality. The average active postoperative arc of motion was 105 degrees (range, 70 degrees to 135 degrees ) compared with 87 degrees (range, 20 degrees to 125 degrees ) preoperatively. Incomplete radiolucencies were noted on all of the postoperative radiographs made after the total knee arthroplasties. There was a high rate of infection (three patients), patellar tendon disruption (two patients), and postoperative secondary procedures (three patients required closed manipulation). The patients with infection were considered to have a failure of treatment: two required arthrodesis, and one required a two-stage exchange. CONCLUSION: On the basis of our results, we concluded that total knee arthroplasty after open reduction and internal fixation of a fracture of the tibial plateau decreases pain and improves knee function, but the procedure is technically demanding and is associated with a high failure rate (five of fifteen).
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Artroplastia de Reemplazo de Rodilla , Fijación Interna de Fracturas , Fracturas de la Tibia/cirugía , Adulto , Anciano , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Insuficiencia del TratamientoRESUMEN
Between July 1977 and December 1983, 80 patients underwent 120 arthroplasties using a total condylar knee prostheses. Forty-one patients (68 knees) died and 13 patients were lost to followup. Twenty-six patients with 34 total condylar replacements were available for clinical followup. During the followup, 10 knees in nine patients (8.3%) from the overall 80 patients (120 knees) underwent revision; three (four knees) for aseptic loosening, one for periprosthetic fracture, three for infection, and two patients underwent revision for pain. Three revisions (three patients) occurred in the group of 26 patients available for followup. The average age of this group of patients at followup was 78 years (range, 53-94 years). There were 10 men and 16 women. Considering the high mean age of the patients in the series and patients' overall health status, the clinical results were extremely good. Kaplan-Meier analysis showed a survivorship of 91% at 23 years followup, considering revision as an end point. Although there have been several changes in total knee replacement designs, materials, and implantation techniques, the long-term outcome of the original total condylar knee prosthesis is excellent.
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Artroplastia de Reemplazo de Rodilla , Adulto , Anciano , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Patients' expectations of medical care are linked to their requests for treatment and to their assessments of outcome and satisfaction. Our goals were to measure patients" preoperative expectations of knee surgery and to develop and test patient-derived knee expectations surveys. METHODS: An initial sample of 377 patients (mean age, 54.6 18.2 years; 52% women) was enrolled in the survey-development phase. One hundred and sixty-one (43%) of these patients subsequently underwent total knee arthroplasty; seventy-five (20%), cruciate ligament repair; eighty-five (23%), meniscal surgery; and fifty-six (15%), surgery for another knee condition. Preoperatively, these patients were asked open-ended questions about their expectations of knee surgery. Their responses were grouped with use of qualitative research techniques to generate categories of expectations. Categories were transformed into specific questions and were formatted into two draft surveys, one for patients undergoing total knee arthroplasty and one for patients undergoing other surgical procedures on the knee. A second sample of 163 patients (mean age, 55.1 17.5 years; 49% women) was enrolled in the survey-testing phase, and they completed the draft surveys on two separate occasions to establish test-retest reliability. Items were selected for the final surveys if they were cited by 5% of the patients, if they represented important functional changes resulting from surgery, or if they represented potentially unrealistic expectations. All selected items fulfilled reliability criteria, defined as a kappa (or weighted kappa) value of 0.4, or were deemed to be clinically relevant by a panel of orthopaedic surgeons. RESULTS: From the survey-development phase, a total of fifty-two categories of expectations were discerned; they included both anticipated items such as pain relief and improvement in walking ability and unanticipated items such as improving psychological well-being. Expectations varied by diagnosis and patient characteristics, including functional status. Two final surveys were generated: the seventeen-item Hospital for Special Surgery Knee Replacement Expectations Survey and the twenty-item Hospital for Special Surgery Knee Surgery Expectations Survey. Each required less than five minutes to complete. CONCLUSIONS: Patients have multiple expectations of knee surgery in the areas of symptom relief and improvement of physical and psychosocial function, and these expectations vary according to the diagnosis. We developed two valid and reliable surveys that can be used preoperatively to direct patient education and shared decision-making and to provide a framework for setting reasonable goals. Reexamining patients' responses postoperatively could provide a way to assess fulfillment of expectations, which is a crucial patient-derived measure of outcome and satisfaction.
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Artropatías/cirugía , Articulación de la Rodilla/cirugía , Procedimientos Ortopédicos/métodos , Satisfacción del Paciente , Adulto , Factores de Edad , Anciano , Femenino , Encuestas Epidemiológicas , Humanos , Artropatías/diagnóstico , Modelos Logísticos , Masculino , Persona de Mediana Edad , Ciudad de Nueva York , Procedimientos Ortopédicos/efectos adversos , Evaluación de Resultado en la Atención de Salud , Dimensión del Dolor , Participación del Paciente , Valor Predictivo de las Pruebas , Cuidados Preoperatorios , Rango del Movimiento Articular/fisiología , Reproducibilidad de los Resultados , Muestreo , Sensibilidad y Especificidad , Factores Sexuales , Resultado del TratamientoRESUMEN
We have assessed the effect of the donation of autologous blood and the preoperative level of haemoglobin on the prevalence of postoperative thromboembolism in 2043 patients who had a total hip arthroplasty. The level of haemoglobin was determined seven to ten days before surgery and all patients had venography of the operated leg on the fifth postoperative day. The number of patients who had donated autologous blood (1037) was similar to that who had not (1006). A significant decrease in the incidence of deep-vein thrombosis (DVT) was noted in those who had donated blood preoperatively (9.0%) compared with those who had not (13.5%) (p = 0.003). For all patients, the lower the preoperative level of haemoglobin the less likely it was that a postoperative DVT would develop. Of those who had donated blood, 0.3% developed a postoperative pulmonary embolism compared with 0.7% in those who had not, but this difference was not statistically significant. No significant difference was found in the requirements for transfusion between the two groups.
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Artroplastia de Reemplazo de Cadera , Donantes de Sangre , Transfusión de Sangre Autóloga , Complicaciones Posoperatorias/sangre , Trombosis de la Vena/sangre , Anciano , Femenino , Hemoglobinometría , Humanos , Masculino , Persona de Mediana Edad , Complicaciones Posoperatorias/prevención & control , Factores de Riesgo , Trombosis de la Vena/prevención & controlRESUMEN
Bipolar hemiarthroplasty has been widely used for the treatment of femoral neck fractures in elderly patients. Outcome studies show excellent results with near preoperative ambulation and lasting, painless hip function. However, what has only recently been considered is that, in some cases, failure of bipolar hemiarthroplasty may be due to wear of the thin, ultra-high-molecular weight polyethylene (UHMWPE) insert between the inner and outer bearings of the prosthesis with subsequent generation of particulate debris, periprosthetic osteolysis, and stem loos ening. We reviewed 31 consecutive bipolar hemiarthroplasties converted to total hip arthroplasties by a single surgeon between 1986 and 1994. The average time to failure was 38 months. Fifty-six percent of the cases showed radiographic evidence of osteolysis around the stem. Radiographic migration of the bipolar head of more than 1 mm into the pelvis, suggestive of cartilage wear, occurred in 67% of the cases. Among the patients with radiographic osteolysis and a loose stem at the time of revision, 92% showed a characteristic histiocytic and giant cell reaction to polyethylene particles in tissue obtained during surgery. The UHMWPE liners from the retrieved outer shells showed an average wear rate of 0.7 mm per year. Recent studies comparing bipolar to unipolar hemiarthroplasty show little difference between the two with regard to morbidity, mortality, or functional outcome. In light of our findings, it might be prudent to reconsider the design and indications for bipolar hemiarthroplasty.
Asunto(s)
Artroplastia de Reemplazo de Cadera , Artroplastia/métodos , Prótesis de Cadera , Falla de Prótesis , Adulto , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Femenino , Reacción a Cuerpo Extraño/diagnóstico , Prótesis de Cadera/efectos adversos , Humanos , Masculino , Persona de Mediana Edad , Polietilenos , Reoperación , Estudios Retrospectivos , Propiedades de Superficie , Resultado del TratamientoRESUMEN
BACKGROUND: Dislodgment of the polyethylene liner is an increasingly common complication following total hip arthroplasty. The purposes of this study are to present the results in a series of patients with this complication and to analyze the mode of failure. METHODS: Between November 1995 and January 2001, eighteen patients who had had a total hip arthroplasty presented with dislodgment of the polyethylene liner from a Harris-Galante metal acetabular shell. The medical records, radiographs, operative notes, and retrieved components were reviewed. In addition, scanning electron microscopy was used to study the fractured surfaces in a shell that had four broken tines. RESULTS: The components had been in situ for an average of seven years (range, three to eleven years). Seventeen components were second generation, and one was first generation. Symptoms developed spontaneously in sixteen patients, during sexual intercourse in one, and following a fall on the hip in one. Radiographs showed eccentric positioning of the head in all of the hips and broken tines in six. All of the shells were well fixed. Treatment consisted of revision of the shell in four patients, exchange of the liner in four, cementation of a new liner into the shell in seven, and cementation of an all-polyethylene cup in three. The liners had severe damage of the rim. Scanning-electron microscopy of the fractured surfaces of four tines revealed a fatigue pattern. CONCLUSIONS: We believe that, as the liner wears and becomes loose because of an inadequate locking mechanism, progressive micromotion occurs and the load increases on the polyethylene rim until it deforms and/or fractures. Subsequently, nothing prevents the liner from rotating out of the shell. As this mechanism of failure appears to include fatigue failure of the locking tines and wear of the liner, this complication is likely to increase as the components age in situ.