***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 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 Abstract Objective To examine the extent and nature of outcome reporting bias in a broad cohort of published r and omised trials . Design Retrospective review of publications and follow up survey of authors . Cohort All journal articles of r and omised trials indexed in PubMed whose primary publication appeared in December 2000 . Main outcome measures Prevalence of incompletely reported outcomes per trial ; reasons for not reporting outcomes ; association between completeness of reporting and statistical significance . Results 519 trials with 553 publications and 10 557 outcomes were identified . Survey responders ( response rate 69 % ) provided information on unreported outcomes but were often unreliable — for 32 % of those who denied the existence of such outcomes there was evidence to the contrary in their publications . On average , over 20 % of the outcomes measured in a parallel group trial were incompletely reported . Within a trial , such outcomes had a higher odds of being statistically non-significant compared with fully reported outcomes ( odds ratio 2.0 ( 95 % confidence interval 1.6 to 2.7 ) for efficacy outcomes ; 1.9 ( 1.1 to 3.5 ) for harm outcomes ) . The most commonly reported reasons for omitting efficacy outcomes included space constraints , lack of clinical importance , and lack of statistical significance . Conclusions Incomplete reporting of outcomes within published articles of r and omised trials is common and is associated with statistical non- significance . The medical literature therefore represents a selective and biased subset of study outcomes , and trial protocol s should be made publicly available 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 OBJECTIVE The aim is of this prospect i ve r and omised study was to investigate the necessity of resurfacing the patella in combination with total knee arthroplasty in patients without or mild anterior knee pain before undergoing total knee replacement .  METHODS Between May 1999 and May 2000 fifty patients were enrolled in a prospect i ve , r and omised study . All patients received the same posterior-cruciate-sparing total knee replacement and were r and omised to treatment with and without resurfacing of the patella .  Inclusion criteria were primary osteoarthritis of the knee , preoperatively no pain when the patella was shifted during clinical examination , a maximal grade III radiological degeneration of the patella according to Sperner et al. and at most a mild anterior knee pain in preoperative interview . Evaluations consisted of the determination of the Knee Society clinical score , the completion of a patient satisfaction question naire , and radiographic assessment basing on the Knee Society roentgenographic evaluation and scoring system . All patients were examined preoperatively and 3 , 6 , and 12 months postoperatively . RESULTS In all postoperative examinations patients with patella resurfacing demonstrated a higher overall Knee Society score . At month 6 the difference was statistically significant . The patient satisfaction question naire demonstrated no significant difference between both groups . However , regarding to relief of anterior knee pain and improvement of pain in general patients with nonresurfacing were less satisfied at all follow-ups . Furthermore , after 12 months all answers to the patient satisfaction question naire of the resurfaced group were better . Patella-associated revisions were performed in two patients without resurfacing . Radiographic analysis demonstrated no loosening , fracture , subluxation or dislocation . CONCLUSION The presented study demonstrated after one year follow-up a better functional result , a higher degree of contentment and fewer complications after total knee replacement with patella resurfacing in patients without or mild preoperative anterior knee pain 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 Summary We suggest a three-step approach when using an article from the surgical literature to guide your patient care : ( 1 ) assess whether the study can provide valid results , ( 2 ) review the results , and ( 3 ) consider how the results might be applied to your patient . R and omization , concealment , intention-to-treat analysis , similarity of patients for known prognostic factors , blinding of patients and outcome assessors , and completeness of follow-up are important guides to study validity . The 95 % confidence interval around the treatment effect is a measure of precision . Consider whether all of the clinical ly important outcomes were reported and whether the likely benefits of treatment outweigh the potential harm and costs Patellofemoral problems are a common cause of morbidity and reoperation after total knee arthroplasty . We made a prospect i ve study of 52 patients who had bilateral arthroplasty ( 104 knees ) and in whom the patella was resurfaced on one side and not on the other . A movable-bearing prosthesis with an anatomical femoral groove was implanted on both sides by the same surgeon using an otherwise identical technique . The mean follow-up was 5.24 years ( 2 to 10 ) . In the 30 available patients ( 60 knees ) there was no difference between the two sides in subjective preference , performance on ascending and descending stairs or the incidence of anterior knee pain . Radiographs showed no differences in prosthetic alignment , femoral condylar height , patellar congruency or joint line position . The use of an appropriate prosthetic design and careful surgical technique can provide equivalent results after knee arthroplasty with or without patellar resurfacing . Given the indications and criteria , which we discuss , retention of the patellar surface is an acceptable option To find out the improvement of joint position sense after  total knee arthroplasty with patellar resurfacing  compared to total knee arthoplasty without patellar resurfacing , the study was carried out as a r and omised parallel trial in patients who had stage III and IV primary osteoarthrosis of only 1 side of the knee with a 2 year follow-up . Twenty-one patients underwent patellar resurfacing and 26 patients had no patellar resurfacing .  Joint position sense was evaluated by the average absolute different angle of the operated knees from the non operated knees which was the asymptomatic knee and acted as the reference knee . Position sense was improved significantly in both groups . However , the patients without patellar resurfacing had better improvement . The patients with patellar resurfacing had better results in terms of anterior knee pain and tenderness .  Patellar resurfacing should be used in severe articular cartilage damage , not as a routine operation Patellar resurfacing in total knee arthroplasty remains controversial . This study evaluates the results of resurfacing and nonresurfacing the patella in a r and omized controlled , clinical trial at a minimum of 10 years followup . One hundred knees ( 90 patients ) with osteoarthritis were enrolled in a prospect i ve r and omized clinical trial using a  posterior – cruciate-retaining total knee arthroplasty . Patients were r and omized to  receive resurfacing or retention of the patella .  Evaluations were done preoperatively and yearly , up to a minimum of 10 years ( range , 10.1–11.5 years ) postoperatively . Disease-specific ( Knee Society clinical rating score ) and functional ( stair climbing , flexion/extension torques , patellar examination ) outcomes were measured . Patient satisfaction , anterior knee pain , and patellofemoral question naires were completed . Intraoperative grading of the articular cartilage was done . No patients were lost to followup ; 45 patients remained alive . Nine revisions ( in nine of 90 knees ; 10 % ) were done in seven patients in the nonresurfaced group ( 15 % of knees ) and in two patients in the resurfaced group ( 5 % of knees ) . No significant difference was found between the groups regarding revision rates , Knee Society clinical rating scores , and functional , patient satisfaction , anterior knee pain , patellofemoral , and radiographic outcomes . Intraoperative cartilage quality was not a predictor of outcome . This study currently is the longest followup of a r and omized controlled , clinical trial that examines patellar resurfacing in total knee arthroplasty . The results showed no significant difference between the groups for all outcome measures at a minimum of 10 years of followup Patellar resurfacing in total knee arthroplasty is a topic debated in the literature . Concerns include fracture , dislocation , loosening , and extensor mechanism injury . Residual anterior knee pain has been reported when the patella is not resurfaced . One hundred patients with osteoarthritic knees were prospect ively r and omized to either have their patella resurfaced or left not resurfaced . All patients were treated with a single prosthesis that featured an anatomically design ed patellofemoral articulation ( Anatomic Medullary Knee , DePuy , Warsaw , IN ) Two patients in the unresurfaced group and one in the resurfaced group required repeat surgery for patellofemoral complications . At 8- to 10-year follow-up evaluations , Knee Society Clinical Ratings scores were not different between the 2 groups . Rates of anterior knee pain with walking and stair climbing were significantly less in the resurfaced group . Eighty percent of patients with a resurfaced patella were extremely satisfied with their total knee arthroplasty versus 48 % without patellar resurfacing . When satisfied and extremely satisfied patients were grouped together , there was no difference between the 2 groups A series of 100 consecutive osteoarthritic patients was r and omised to undergo  total knee replacement using a Miller-Galante II prosthesis , with or without a cemented polyethylene patellar component .  Knee function was evaluated using the American Knee Society score , Western Ontario and McMaster University Osteoarthritis index , specific patellofemoral-related questions and radiographic evaluation until the fourth post-operative year , then via question naire until ten years post-operatively . A ten 
    Output:
    
The evidence suggests that patellar resurfacing would reduce the risk of anterior knee pain , as well as the risk of patella-related reoperation .
Furthermore , patients not undergoing patella resurfacing would experience more knee pain during stair climbing and be less satisfied with surgery .
No significant difference in range of motion can be expected with or without patellar resurfacing .