***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 The primary purpose of this r and omized controlled trial ( RCT ) was to compare knee-specific outcomes ( stiffness , pain , function ) between patellar retention and resurfacing up to 10 years after primary total knee arthroplasty ( TKA ) . Secondarily , we compared re-operation rates . Methods 38 subjects with non-inflammatory arthritis were r and omized at primary TKA surgery to receive patellar resurfacing ( n = 21 ; Resurfaced group ) or to retain their native patella ( n = 17 ; Non-resurfaced group ) . Evaluations were performed preoperatively , one , five and 10 years postoperatively by an evaluator who was blinded to group allocation . Self-reported knee-specific stiffness , pain and function , the primary outcomes , were measured by the Western Ontario McMaster Osteoarthritis Index ( WOMAC ) . Revision rate was determined at each evaluation and through hospital record review . Results 30 ( 88 % ) and 23 ( 72 % ) of available subjects completed the five and 10-year review respectively . Knee-specific scores continued to improve for both groups over the 10-years , despite diminishing overall health with no significant group differences seen . All revisions occurred within five years of surgery ( three Non-resurfaced subjects ; one Resurfaced subject ) ( p = 0.31 ) . Two revisions in the Non-resurfaced group were due to persistent anterior knee pain . Conclusions We found no differences in knee-specific results between groups at 5–10 years postoperatively . The Non-resurfaced group had two revisions due to anterior knee pain similar to rates reported in other studies . Knee-specific results provide useful postoperative information and should be used in future studies comparing patellar management strategies . Clinical Trials.gov BACKGROUND The need for patella resurfacing remains an area of considerable controversy in total knee replacement surgery . There would appear to be no reported evidence on the effect of patella resurfacing on knee function , as measured by functional range of movement used in a series of tasks , in patients undergoing knee replacement . The object of this study was to measure knee joint motion during functional activities both prior to and following total knee replacement in a r and omised group of patients with and without patella resurfacing and to compare these patient groups with a group of normal age-matched subjects . METHODS The study design was a double blinded , r and omised , prospect i ve , controlled trial . The knee joint functional ranges of movement of a group of patients ( n=50 , mean age=70 years ) with knee osteoarthritis were investigated prior to and following total knee arthroplasty ( 4 months and 18 - 24 months ) along with a group of normal subjects ( n=20 , mean age=67 ) . Patients were r and omly allocated into two groups , those who received patella resurfacing ( n=25 ) and those who did not ( n=25 ) . Flexible electrogoniometry was used to measure the flexion-extension angle of the knees with respect to time in eleven functional activities . FINDINGS No statistically significant differences ( alpha level 0.05 ) in joint excursion of the affected knee were found between patients who received patella resurfacing and those who did not . INTERPRETATION Routine patella resurfacing in a typical knee arthroplasty population does not result in an increase in the functional range of movement used after knee replacement BACKGROUND In total knee arthroplasty ( TKA ) , h and ling of the patella surface is still quite controversial . We carried out a prospect i ve r and omized study to compare circumpatellar electrocautery plus patella resurfacing vs circumpatellar electrocautery only in the single-staged bilateral TKA in Chinese population . METHODS One hundred five patients diagnosed with late-staged osteoarthritis who received single-staged bilateral TKA were screened and 53 patients were included . All patients received the same posterior cruciate-stabilizing total knee prostheses . Patients were r and omized to receive circumpatellar electrocautery plus patellar resurfacing or circumpatellar electrocautery only for the first TKA , and the second knee received the opposite treatment . All patients were followed for a minimum of 2 years . RESULTS No differences were found with regard to Knee Society Score , Feller score , anterior knee pain , and revision rates . Fifty-two percent of patients had no preference with regard to pain and function , 27 % of patients preferred the resurfacing plus circumpatellar electrocautery knee while 21 % of the patients preferred the circumpatellar electrocautery only knee . The Insall-Salvati index and the patella tilt were a little smaller in the resurfacing group . One patient ( 2.1 % ) in the circumpatellar electrocautery group underwent a  patella resurfacing revision for severe anterior knee pain and patella subluxation . CONCLUSION Equivalent clinical results for circumpatellar electrocautery plus resurfacing and circumpatellar electrocautery alone of the patella in TKA were demonstrated in selective Chinese population with thick enough patella Background There is no difference in the functional outcomes 6 months after total knee arthroplasty ( TKA ) for knee osteoarthritis between patellar resurfacing and non-resurfacing . Thus , we have performed this study to compare the short-term clinical outcomes of TKA performed with and without the patella resurfacing . Methods A total of 50 patients with osteoarthritis of the knee ( OAK ) were r and omized to receive patellar resurfacing ( n=24 ; resurfaced group ) or to retain their native patella ( n=26 ; non-resurfaced group ) based on envelope selection and provided informed consent . Disease specific outcomes including Knee Society Score ( KSS ) , Knee Society Function Score ( KSKS-F ) , Kujala Anterior Knee Pain Scale ( AKPS ) , Western Ontario and McMaster Universities Arthritis Index ( WOMAC ) , Short Form 36 ( SF-36 ) , and functional patella-related activities were measured within six months of follow-up . Results There was no significant difference between the resurfaced and non-resurfaced groups in pre and post-operative improvement of range of motion ( ROM ) ( P=0.421 ) , KSS ( P=0.782 , P=0.553 ) , KSKS-F ( P=0.241 , P=0.293 ) , AKPS ( P=0.128 , P=0.443 ) , WOMAC ( P=0.700 , P=0.282 ) , and pain scores ( P=0.120 , P=0.508 ) . There was no difference in ROM between resurfaced and non-resurfaced group pre ( 15.24 ° and 15.45 ° ) and post-operative ( 18.48 ° and 18.74 ) . No side effects related to patella was observed in any of the groups . Revision was required in none of the participants . Conclusion The results showed no significant difference between patellar resurfacing and non-resurfacing in TKA for all outcome measures in a short term . Level of evidence : Introduction :  Anterior knee pain following total knee arthroplasty is estimated to occur in 4 - 49 % of patients . Some orthopedic surgeons use circumpatellar electrocautery ( diathermy ) to reduce the prevalence of postsurgical anterior knee pain ; however , the extent of its use is unknown . Material s and Methodology : In April 2009 , a postal question naire was sent to all 98 departments of orthopedic surgery in The Netherl and s. The questions focused on the frequency of  total knee arthroplasties , patellar resurfacing  , and the use of circumpatellar electrocautery .  Results : The response rate was 92 % . A total of 18,876 TKAs , 2,096 unicompartmental knee arthroplasties , and 215 patellofemoral arthroplasties are performed yearly in The Netherl and s by the responding orthopedic surgeons . Of the orthopedic surgeons performing TKA , 13 % always use  patellar resurfacing  in total knee arthroplasty for osteoarthritis , 49 % use  selective patellar resurfacing  , and 38 % never use it . Fifty-six percent of orthopedic surgeons use  circumpatellar electrocautery  when not resurfacing the patella , and 32 % use  electrocautery  when resurfacing the patella . Conclusion : There is no consensus among Dutch orthopedic surgeons on the use of  patellar resurfacing or circumpatellar electrocautery  in total knee replacement performed for osteoarthritis . A prospect i ve clinical trial is currently underway to fully evaluate the effect of circumpatellar electrocautery on the prevalence of anterior knee pain following total knee arthroplasty Complications of patellar resurfacing in total knee arthroplasty have rekindled the interest of many surgeons in patellar retention . In a prospect i ve study 20 r and omly selected patients of 40 underwent patellar resurfacing in combination with their total knee arthroplasty .  The other 20 patients were left with an unresurfaced patella . Within 24 months of follow-up , the advantages of patellar resurfacing could be seen according to the Knee Society Score . Especially in advanced osteoarthritis of the knee joint , the patients achieved better scores in climbing stairs and in function . The superior functional results are arguments for patellar resurfacing , at least in knees with advanced osteoarthritis Background : Whether to resurface the patella during a primary total knee arthroplasty performed for the treatment of degenerative osteoarthritis remains a controversial issue . Parameters that have been suggested as being useful in guiding this decision include patient height and weight , the presence of anterior knee pain preoperatively , and the grade of chondromalacia encountered intraoperatively . The purpose of this study was to determine whether these parameters were predictive of the clinical result following total knee arthroplasty with or without patellar resurfacing . Methods : Eighty-six patients ( 118 knees ) undergoing primary total knee arthroplasty for the treatment of osteoarthritis were enrolled in a prospect i ve , r and omized , double-blind study . All patients received the same posterior-cruciate-sparing total knee prosthetic components . Patients were r and omized to treatment with or without resurfacing of the patella . Evaluations consisted of the determination of a Knee Society clinical score , the completion of a patient satisfaction question naire , specific questions relating to patellofemoral symptoms , and radiographs .  Sixty-seven patients ( ninety-three knees ) were followed for a minimum of five years ( range , sixty to eighty-four months ; average , 70.5 months ) . Results : With the numbers available , there was no significant difference between the groups treated with and without resurfacing with regard to the overall Knee Society score or the pain and function subscores . Obesity , the degree of patellar chondromalacia , and the presence of preoperative anterior knee pain did not predict postoperative clinical scores or the presence of postoperative anterior knee pain . Conclusions : The occurrence of anterior knee pain could not be predicted with any clinical or radiographic parameter studied . On the basis of these results , it seems likely that postoperative anterior knee pain is related either to the component design or to the details of the surgical technique , such as component rotation , rather than to whether or not the patella is resurfaced 350 knees were evaluated in a prospect i ve , r and omized , double-blinded study of selective patellar resurfacing in primary total knee arthroplasty . Knees with exposed bone on the patellar articular surface were excluded . 327 knees were evaluated at a mean follow-up of 7.8years . 114 knees followed for greater than 10 years were analyzed separately . Satisfaction was higher in patients with a resurfaced patella . In patients followed for at least 10 years , no significant difference was found . No difference was found in KSS scores or survivorship . No complications of patellar resurfacing were identified . The vast majority of patients with remaining patellar articular cartilage do very well with total knee arthroplasty regardless of patellar resurfacing . Patient satisfaction may be slightly higher with patellar resurfacing The aim of this study was to assess medium term results of patellar resurfacing in total knee arthroplasty , specifically looking at anterior knee pain , patellofemoral function and need for reoperation . A prospect i ve cohort study was conducted with patients undergoing staged bilateral knee arthroplasty with the patella being resurfaced only on one side . This was due to change in the clinical practice of the senior author . Sixty patients were review ed clinical ly and radiologically on a regular basis . The surgery was either performed or supervised by the senior author in all cases . All patients received the cemented press-fit condylar © prosthesis . The Knee Society clinical rating system was used . Scores were recorded pre-operatively and post-operatively at three months , one year , two years and three yearly thereafter . The mean age of patients in the study group was 75 years ( range : 62–89 years ) . There were 42 women and 18 men in the study . The mean duration of follow-up was 4.5 years ( range : 2–12 years ) . There was no significant difference in the pre-operative scores in both groups . There 
    Output:
    
Based on the main findings of this meta- analysis , patellar resurfaced TKA was demonstrated to have performed superior overall .
Patellar resurfacing detected a lower rate of postoperative anterior knee pain and reoperation .
Moreover , the resurfacing group showed greater value of the HSS , KSS and related subscales .