***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND There is little in the literature to guide clinicians in advising patients regarding their return to work following a primary total knee arthroplasty . In this study , we aim ed to identify which factors are important in estimating a patient 's time to return to work following primary total knee arthroplasty , how long patients can anticipate being off from work , and the types of jobs to which patients are able to return following primary total knee arthroplasty . METHODS A prospect i ve cohort study was performed in which patients scheduled for a primary total knee arthroplasty completed a vali date d question naire preoperatively and at four to six weeks , three months , and six months postoperatively . The question naire assessed the patient 's occupational physical dem and s , ability to perform job responsibilities , physical status , and motivation to return to work as well as factors that may impact his or her recovery and other workplace characteristics . Two survival analysis models were constructed to evaluate the time to return to work either at least part-time or full-time . Acceleration factors were calculated to indicate the relative percentage of time until the patient returned to work . RESULTS The median time to return to work was 8.9 weeks . Patients who reported a sense of urgency about returning to work were found to return in half the time taken by other employees ( acceleration factor = 0.468 ; p < 0.001 ) . Other preoperative factors associated with a faster return to work included being female ( acceleration factor = 0.783 ) , self-employment ( acceleration factor = 0.792 ) , higher mental health scores ( acceleration factor = 0.891 ) , higher physical function scores ( acceleration factor = 0.809 ) , higher Functional Comorbidity Index scores ( acceleration factor = 0.914 ) , and a h and icap accessible workplace ( acceleration factor = 0.736 ) . A slower return to work was associated with having less pain preoperatively ( acceleration factor = 1.132 ) , having a more physically dem and ing job ( acceleration factor = 1.116 ) , and receiving Workers ' Compensation ( acceleration factor = 4.360 ) . CONCLUSIONS Although the physical dem and s of a patient 's job have a moderate influence on the patient 's ability to return to work following a primary total knee arthroplasty , the patient 's characteristics , particularly motivation , play a more important role Background Prior investigations have suggested that physician-related factors may contribute to differential use of TKA  among women and ethnic minorities . We sought to evaluate the effect of surgeon bias on recommendations for TKA . Questions / purpose Using an experimental approach with st and ardized patient scenarios , we sought to evaluate surgeon recommendations regarding TKA , specifically to determine whether recommendations for TKA are influenced by ( 1 ) patient race , and ( 2 ) patient sex . Methods We developed four computerized scenarios for all combinations of race ( white or black ) and sex ( male or female ) for otherwise similar patients with end-stage knee osteoarthritis . Patients gave an orthopaedic history of 2 years worsening pain with decreased functional status and failure of oral antiinflammatory medications and corticosteroid intraarticular injections . Orthopaedic surgeons attending the 2012 annual meetings of the New York State Society of Orthopaedic Surgeons and American Association of Hip and Knee Surgeons were recruited for the study . Surgeons passing an open recruitment table at each meeting were asked to participate . Of the 1111 surgeons in attendance at either meeting , 113 ( 10.2 % ) participated in the study . All participants viewed the “ control ” patient ’s story ( white male ) and were r and omized to view one of the three “ experimental ” scenarios ( white female , black male , black female ) . After viewing each scenario , the participants were anonymously asked whether they would recommend TKA . An a priori power analysis showed that 112 participants were needed to detect a 15 % difference in the likelihood of recommending surgery for white versus nonwhite patients in the test scenarios evaluated with 90 % power at a level of significance of 0.05 . Results Of the 39 surgeons who viewed the white male plus black female scenario , there were 33 ( 85 % ) concordant responses ( TKA offered to both patients ) and six discordant responses ( TKA offered to only one of the patients ) , with no effect of patient race and sex ( p = 0.99 ) . Of the 37 surgeons who viewed the white male plus black male scenario , there were 33 ( 89 % ) concordant responses and four discordant responses , with no effect of patient race ( p = 0.32 ) . Of the 37 surgeons who viewed the white male plus white female scenario , there were 30 ( 77 % ) concordant responses and seven discordant responses , with no effect of patient sex ( p = 0.71 ) . Conclusion After orthopaedic surgeons viewed video scenarios of patients with end-stage knee osteoarthritis , patient race and sex were not associated with a different likelihood of a surgical recommendation . Our findings support the notion that patient race and sex may be less influential on decision making when there are strong clinical data to support a decision . Physician bias may have a greater effect on decision making in situations where the indications for surgery are less clear The purpose of this study was to compare patient demographics and factors recorded at the time of surgery between patients that were either satisfied or dissatisfied with their TKA at mid-term follow-up . From our prospect i ve outcomes data base , 989 primary TKAs with complete preoperative and intraoperative data were identified . At mean follow-up of 3.5 years , 94/989 TKAs ( 9.5 % ) were not satisfied with their TKA . African American patients were 3.0 times more likely to be dissatisfied than Caucasians ( 95 % CI = 1.5 - 6.0 , P = .003 ) . Patients with less severe degenerative changes  were 2.1 times more likely to be dissatisfied ( 95 % CI = 1.3 - 3.2 , P = .001 ) Total knee arthroplasty has provided dramatic improvements in function and pain for the majority of patients with knee arthritis , yet a significant proportion of patients remain dissatisfied with their results . We performed a prospect i ve analysis of 215 patients undergoing TKA who underwent a comprehensive array of evaluations to discover whether any preoperative assessment could predict high pain scores and functional limitations postoperatively . Patients with severe pain with a simple knee range-of-motion test prior to TKA had a 10 times higher likelihood of moderate to severe pain at 6 months . A simple test of pain intensity with active flexion and extension preoperatively was a significant predictor of postoperative pain at 6 months after surgery . Strategies to address this particular patient group may improve satisfaction rates of TKA 
    Output:
    
US blacks may derive less benefit from TKA than whites as measured by HRQOL , pain , function , and satisfaction .