RESUMEN
BACKGROUND: Aseptic loosening (AL) is a frequent complication after rotating hinge knee (RHK) prosthesis. Citak's ratio has recently been developed to describe and classify distal femoral morphology into 3 groups (A, B, C). It consists in a ratio between the diameters of the femoral canal at 20 cm from the knee joint line and at 2 cm from the adductor tubercle. The objective of the study was to identify whether the femoral distal anatomical shape described with this ratio represents a risk factor for AL in RHK prosthesis. METHODS: Retrospective study of patients who had undergone primary or revision RHK prosthesis, with a follow-up of minimum 4 years. Citak's ratio was calculated, and patients were classified depending on its value. Univariate and bivariate statistical analysis was performed to identify AL risk factors. Receiver Operating Characteristics (ROC) analyses were conducted to examine diagnostic quality of the parameters of interest. RESULTS: Thirty-three patients were included. Most of them females (ratio 26:7), with a mean age of 78.2 (SD 6.9). Three patients presented AL (rate of 9%), all of them classified into group C (100%). Citak's ratio was significantly related to the AL rate (p < 0.001), and so was the femoral canal diameter at 20 cm from the knee joint (p 0.010). The ROC curve analysis yielded an Area Under the Curve (AUC) of 0.922 (CI 95% 0.819-1.000) for the Citak´s ratio. CONCLUSION: The inner femoral diameter at 20 cm proximal to the knee joint line and Citak's ratio help indentify patients at risk of AL after RHK prosthesis, and thus a better planning of the surgery.
RESUMEN
The objective of this study was to evaluate our preliminary results after changing our surgical strategy from 2-stage revision arthroplasty to 1-stage revision arthroplasty for patients with chronic knee periprosthetic joint infection. We conducted a prospective study of knee arthroplasty patients that had been diagnosed with chronic infection and treated using a 1-stage revision regardless of the traditional criteria applied for indication thereof. We evaluated two main variables: infection control and economic costs. The definitive diagnosis of infection of the revision was determined by using the criteria proposed by the Musculoskeletal Infection Society. The costs were calculated as average costs in USD, as described by Srivastava (2019), for 1-stage or 2-stage revisions. Eighteen patients were included in the study, and infection was controlled in 17 patients. The total economic savings for our hospital from these 18 patients amounted to USD 291,152. This clinical success has led to major changes in how our hospital approaches the treatment of chronically infected knee replacements, in addition to substantial economic advantages for the hospital.
RESUMEN
BACKGROUND: The objective of our study is to evaluate our preliminary results after changing from a 2-stage revision arthroplasty protocol to a 1-stage revision arthroplasty protocol using cementless arthroplasty for all patients with chronic infected hip replacements. METHODS: Prospective study of all hip arthroplasties that were diagnosed with chronic infection and were treated using the 1-stage revision without taking into account the traditional criteria used to determine the use of a 1-stage revision was conducted. There were 2 main variables evaluated: infection control and costs. The definitive diagnosis of infection of the revision was determined using the criteria proposed by the Musculoskeletal Infection Society. The costs were calculated using average cost in USD, excluding social expenses, as described by Klouche (2010) for 1-stage or 2-stage revisions. RESULTS: Nineteen patients were included in the study and the infection was controlled in 18 patients. The total economic savings for our hospital for these 19 patients was 391.609 USD. CONCLUSION: This clinical success has led to an important change in our hospital in treating chronic infected hip replacements and an important cost reduction from an economic point of view.