***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 
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    Input: Background In the majority of patients with osteoarthritis of the knee the disease originates in the medial compartment . There are two fundamentally different approaches to knee replacement for patients with unicompartmental disease : some surgeons feel that it is always best to replace both the knee compartments with a total knee replacement ( TKR ) ; whereas others feel it is best to replace just the damaged component of the knee using a partial or unicompartment replacement ( UKR ) . Both interventions are established and well-documented procedures . Little evidence exists to prove the clinical and cost-effectiveness of either management option . This provides an explanation for the high variation in treatment of choice by individual surgeons for the same knee pathology . The aim of the TOPKAT study will be to assess the clinical and cost effectiveness of TKRs compared to UKRs in patients with medial compartment osteoarthritis . Methods / Design The design of the study is a single layer multicentre superiority type r and omised controlled trial of unilateral knee replacement patients . Blinding will not be possible as the surgical scars for each procedure differ . We aim to recruit 500 patients from approximately 28 secondary care orthopaedic units from across the UK including district general and teaching hospitals . Participants will be r and omised to either UKR or TKR . R and omisation will occur using a web-based r and omisation system . The study is pragmatic in terms of implant selection for the knee replacement operation . Participants will be followed up for 5 years . The primary outcome is the Oxford Knee Score , which will be collected via question naires at 2 months , 1 year and then annually to 5 years . Secondary outcomes will include cost-effectiveness , patient satisfaction and complications data .Trial registration Current Controlled Trials IS RCT N03013488 ; Clinical Trials.gov Identifier : Abstract Purpose During recent years , there has been an intensive growth of interest in the patient ’s perception of functional outcome . The Forgotten Joint Score ( FJS ) is a recently introduced score that measures joint awareness of patients who have undergone knee arthroplasty and is less limited by ceiling effects . The aim of this study was to compare the FJS between patients who undergo medial unicompartmental knee arthroplasty ( UKA ) and patients who undergo total knee arthroplasty ( TKA )  1 and 2 years post-operatively . Methods This prospect i ve study compares the FJS at a minimum of one ( average 1.5 years , range 1.0–1.9 ) and a minimum of 2 years ( average 2.5 years , range 2.0–3.6 ) post-operatively between patients who underwent medial UKA and TKA .  Results One-hundred and thirty patients were included . Sixty-five patients underwent medial UKA and 65 patients underwent TKA . At both follow-up points , the FJS was significantly higher in the UKA group ( FJS 1 year 73.9 ± 22.8 , FJS 2 year 74.3 ± 24.8 ) in contrast to the TKA group ( FJS 1 year 59.3 ± 29.5 ( p = 0.002 ) , FJS 2 year 59.8 ± 31.5 , ( p = 0.004 ) ) . No significant improvement in the FJS was observed between 1- and 2-year follow-up of the two cohorts . Conclusion Patients who undergo UKA are more likely to forget their artificial joint in daily life and consequently may be more satisfied . Level of evidence II Purpose Unicompartmental knee replacement preserves uninvolved osteocartilaginous and soft tissue structures , thereby allowing a more physiological and early clinical and functional recovery . The aim of this study was to report the results of  ZUK unicompartmental fixed metal-back prosthesis and how these results change over time . Methods Between 2005 and 2007 , 80 ZUK prostheses were implanted in 80 patients for unicompartmental osteoarthritis or osteonecrosis . Patients were clinical ly assessed using the International Knee Society scores . Postoperative values of mechanical axis were calculated 12 months after surgery and compared to the preoperative ones . Results The mean International Knee Society knee and function scores improved , respectively , from 46 ± 9 and 54 ± 8 preoperatively to 82 ± 5 and 94 ± 3 at the last follow-up ( P < 0.001 ) . Average flexion increased from 110 ° ± 9 ° to 127 ° ± 8 ° ( P < 0.01 ) . Patients with unicompartmental knee reached good clinical outcome very early and remained at the same level . Age did not significantly influence clinical and functional scores . Conclusions High success rates of the modern unicompartmental knee implants depend on the material s and design evolution , improvement of the surgical technique , and the strong restriction of indications . Level of evidence Prospect i ve non-r and omized case-series study , Level IV BACKGROUND Improvements in surgical techniques , implant design , and adherence to indications have result ed in favorable outcomes after unicompartmental knee arthroplasty ( UKA ) , particularly in an older population . However , no studies have compared the performance of contemporary UKA and total knee arthroplasty ( TKA ) in a young population . METHODS Prospect ively collected registry data of 160 UKAs performed in 160 patients younger than 55 years were review ed . Propensity scores generated using logistic regression were used to adjust for confounding variables of age , gender , body mass index , preoperative range of motion , Knee Society Score , Oxford Knee Score , and Short-Form 36 , allowing matching of the TKA cohort to the UKA cohort in a 1:1 ratio using the nearest-neighbor method . RESULTS The UKA group had significantly greater flexion at 6 months and 2 years ( P < .001 ) . There was no significant difference in Knee Society Score , Oxford Knee Score , and Short-Form 36 . At 2 years , 89.4 % and 88.8 % of the TKA and UKA groups were satisfied ( P = 1.00 ) while 86.9 % and 86.3 % had their expectations fulfilled ( P = 1.00 ) . At a mean follow-up of 7 years , there were 2 revisions in each group ( 2.2 % ) . CONCLUSION Although native knee biomechanics are preserved , younger patients do not seem to perceive this oft-cited benefit of UKA , as this did not translate into greater health-related quality of life or patient satisfaction compared to TKA . The theoretical advantages of UKA were not borne out by our findings , other than greater flexion up to 2 years postoperatively The objective of this study was to evaluate incremental cost-utility of total knee replacement ( TKR ) versus unicompartmental knee arthroplasty ( UKA ) in patients with knee osteoarthritis ( OA ) of the medial compartment . A 2-year non-r and omised prospect i ve observational cohort study was conducted in unicompartmental knee osteoarthritis patients scheduled for TKR ( n = 431 ) or UKA ( n = 102 ) .  Costs were identified using administrative data bases and health outcomes were measured using the SF-36 and the Oxford knee score ( OKS ) 1 week before , 6 months after , and 2 years after surgery . The incremental cost-utility ratio ( ICUR ) for TKR versus UKA was calculated and its 95 % confidence interval estimated using a nonparametric bootstrapping technique . Cost-effectiveness acceptability curves were constructed from different perspectives . On average , from the societal perspective , the ICUR was US $ 65,245 per quality -adjusted life-year ( QALY ) . In the scenario with costs calculated from the perspective of patients , the ICUR was $ 60,382/QALY . This value decreased to $ 4,860/QALY in the scenario with costs calculated from the governmental perspective . However , the 95 % confidence interval of ICURs can not be defined because more than 5 % bootstrapped sample s fell into the upper left quadrant of the cost-effectiveness plane from all three perspectives . Based on the 2-year data , TKR gained more QALYs at higher costs compared to UKA . A long-term prospect i ve study is necessary to determine cost-effectiveness of TKR and UKA BACKGROUND With increasing number of patients with early osteoarthritis of knee opting for total knee arthroplasty ( TKA ) , there has been increase in patients dissatisfied with surgical outcomes . It is being presumed that offering unicondylar knee arthroplasty ( UKA ) to them would improve outcomes . METHODS Primary objective of our study was to look for any difference in patient-reported outcome and function at 2-year follow-up in patients undergoing UKA as compared to TKA .  Our study was a r and omized study with parallel assignment conducted at a high-volume specialized arthroplasty center . Eighty patients with bilateral isolated medial compartment knee arthritis were r and omized into simultaneous 2-team bilateral TKA ( n = 40 ) and UKA ( n = 40 ) group . We finally analyzed 36 patients in each group . Main outcome measure was improvement in Knee Outcome Survey-Activities of Daily Living Scale ( KOS-ADLS ) and High Activity Arthroplasty Score ( HAAS ) obtained at 2-year follow-up . RESULTS Improvement in KOS-ADLS and HAAS at 2 years was similar ( P = .2143 and .2010 ) in both groups . Performance as assessed with Delaware index was also similar . Length of hospital stay was less in UKA group ( 6.6 days as against 5.4 days ) . Complications and readmission rates were more in TKA group ( nil in UKA group ; 08 in TKA group ) . CONCLUSION At 2-year follow-up , UKA provides similar improvement in patient-reported outcomes , function , and performance as compared to TKA when performed in patients with early arthritis . However , UKA patients have shorter hospital stay and fewer complications We r and omised 102 knees suitable for a unicompartmental replacement to receive either a unicompartmental ( UKR ) or total knee replacement ( TKR ) after arthrotomy . Both groups were well matched with a predominance of females and a mean age of 69 years . Patients in the UKR group showed less perioperative morbidity , but regained knee movement more rapidly and were discharged from hospital sooner . At five years , two UKRs and one TKR had been revised ; another TKR was radiologically loose . All other knees appeared to be clinical ly and radiologically sound . Pain relief was good in both groups but the number of knees able to flex > or = 120 degrees was significantly higher in the UKR group ( p < 0.001 ) and there were more excellent results in this group . Our findings have shown that UKR gives better results than TKR and that this superiority is maintained for at least five years BACKGROUND Whether patient-reported symptoms and function after  total knee arthroplasty ( TKA ) and medial unicompartmental knee arthroplasty ( UKA )  compare favorably to similar individuals without a diagnosis of knee pathology has not been investigated . METHODS A retrospective , multicenter study was design ed in which 4 centers contributed patients between ages 18 and 80 years undergoing knee arthroplasty .  Data were collected by an independent , third-party survey center that administered a question naire assessing patient satisfaction and function . The survey center identified a " control " population of the same age range using a " r and om digit dial call method " with no prior knee interventions or major problems with their knees limiting their activity . Comparisons were performed using multivariate logistic regression analyses accounting for differences in demographic variables among the 3 cohorts . RESULTS Overall , 1456 TKAs , 476UKAs , and 409 controls were included for analysis . Controls reported a surprisingly high incidence of pain ( 30 % ) , a limp ( 26 % ) , stiffness ( 22 % ) , and noise ( 21 % ) in their knee . However , the likelihood of reported noise ( odds ratio [ OR ] , 1.3 ) , swelling ( OR , 1.4 ) , stiffness ( OR , 1.8 ) , and difficulty getting in and out of a chair ( OR , 2.5 ) was increased after TKA vs controls ( P < .001-.03 ) . The likelihood of swelling ( OR , 1.8 ) , stiffness ( OR , 1.5 ) , and difficulty getting in and out of a chair ( OR , 1.7 ) was increased after UKA vs controls ( P = .002-.005 ) . CONCLUSION When interviewed by an independent , third party , a substantial percentage of control patients reported the presence of knee symptoms , but to a lesser degree than patients after a knee arthroplasty We prospect ively evaluated a consecutive series of 56 patients with unicompartmental knee arthritis who underwent unicompartmental knee replacement or total knee arthroplasty and received an average of 52months of follow-up . These patients were enrolled in a prospect i ve r and omized clinical trial . There were no significant differences in the pre-operative parameters of both groups . All the patients were followed up and evaluated preoperatively and yearly , the data was collected and statistical analysis was performed . At an average of 52months after surgery the mean Knee Society score was 80.5 ( range : 70 - 100 ) and 78.9 ( range : 70 - 87 ) for Unicompartmental knee replacement and total knee arthropl 
    Output:
    
Conclusions TKA and UKA are both viable options for the treatment of isolated unicompartmental osteoarthritis .
By directly comparing the two treatments , this study demonstrates better results for UKA in several outcome domains .
However , the risk of revision surgery was lower for TKA .