***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 Knee arthroscopy is among the most common orthopaedic surgical procedures . However , the incidence and risk factors for postsurgical morbidity and mortality remain poorly defined . METHODS The American College of Surgeons National Surgical Quality Improvement Program prospect ively collects thirty-day morbidity and mortality data from more than 258 hospitals around the United States . We used Current Procedural Terminology codes to retrospectively query the data base and identified 12,271 cases of elective knee arthroscopy performed from January 1 , 2005 , to December 31 , 2010 . Postoperative complications were divided into categories of minor morbidity , major morbidity or mortality , or any complication . The potential risk factors for complications were analyzed with use of univariate and multivariate analyses . RESULTS The overall incidence of any complication was 1.6 % ( 199 patients ) . The major morbidity was 0.76 % ( ninety-three patients ) , which included one patient death ( 0.008 % ) , and the minor morbidity was 0.86 % ( 106 patients ) . The most frequent major complication was a return to the operating room . The most common minor complication was deep venous thrombosis or thrombophlebitis . The risk factors identified in the univariate analysis for any complication included black race , prior operation within thirty days , American Society of Anesthesiologists class , and operative time of > 1.5 hours as compared with ≤1.5 hours ( p < 0.05 for each ) . The independent risk factors identified in the multivariate analysis for any complication included black race ( odds ratio , 1.81 [ 95 % confidence interval , 1.13 to 2.89 ] ) , prior operation within thirty days ( odds ratio , 6.33 [ 95 % confidence interval , 1.45 to 27.66 ] ) , operative time of > 1.5 hours ( odds ratio , 1.84 [ 95 % confidence interval , 1.21 to 2.78 ] ) , and age of forty to sixty-five years ( odds ratio , 1.46 [ 95 % confidence interval , 1.01 to 2.11 ] ) . CONCLUSIONS The incidence of complication following elective knee arthroscopy is low . The data presented here should be useful for providing prognostic information to patients during informed consent . Surgeons should be encouraged to minimize operative time whenever possible , and may wish to delay elective arthroscopy in patients who have had other recent surgical procedures A prospect i ve cohort study was undertaken at two centers to look for the incidence of deep vein thrombosis ( DVT ) following  knee arthroscopic surgery . Eighty-four patients who had 90 arthroscopic procedures  were review ed . The relevant risk factors : past or family history of DVT , smoking , oral contraceptives , body weight , haemoglobin level , platelet count , tourniquet time and type of anaesthesia were documented . All patients were subjected to preoperative and post-operative duplex ultrasound .  Only one patient ( 1.2 % ) was noted to have DVT involving the peroneal vein . We concluded that the incidence of DVT after knee arthroscopy was very low in this study population In this prospect i ve r and omised study two treatments after non-traumatic medial meniscal tear diagnosed with radiological examination and magnetic resonance imaging were compared ; arthroscopic partial meniscectomy followed by supervised exercise or supervised exercise alone . The aim was to evaluate knee function and physical activity . Ninety patients ( mean age 56 years ) were evaluated using the  Knee Injury and Osteoarthritis Outcome Score , the Lysholm Knee Scoring Scale , the Tegner Activity Scale and a Visual Analogue Scale for knee pain prior to the intervention , after 8 weeks of exercise and after 6 months . According to the outcome scores arthroscopic partial medial meniscectomy combined with exercise did not lead to greater improvement than exercise alone . After the intervention both groups reported decreased knee pain , improved knee function and a high satisfaction ( P < 0.0001 ) . Forty-one per cent of the patients returned to their pre-injury activity level after 6 months . In conclusion , when evaluated with outcome scores , arthroscopic partial medial meniscectomy followed by supervised exercise was not superior to supervised exercise alone in terms of reduced knee pain , improved knee function and improved quality of life PURPOSE The risk of deep vein thrombosis ( DVT ) in patients undergoing arthroscopic knee surgery is not well known . The purpose of this study was to determine the incidence of DVT , to demonstrate the efficacy of a perioperative and postoperative prophylaxis against thromboembolism with use of low -- molecular weight heparin ( LMWH ) , and to show the safety and feasibility of LMWH administration . TYPE OF STUDY Prospect i ve , single-blind , r and omized clinical trial . METHODS There were 218 consecutive out patients scheduled for ambulatory arthroscopic knee surgery eligible . Of these , 130 patients were r and omized to a treatment group with LMWH ( dalteparin : 2,500 IU less-than-or-equal70 kg and 5,000 IU > 70 kg , started perioperatively and given once daily for 4 weeks ; n = 66 ) and a control group ( n = 64 ) with no prophylaxis . To detect DVT , all patients underwent bilateral compression ultrasonography before and 12 and 31 days after surgery . RESULTS Among the 130 patients studied , thromboembolism was significantly lower in the treatment than in the control group : 1 of 66 ( 1.5 % ) versus 10 of 64 ( 15.6 % ) ; 95 % confidence interval , 7.8 % to 26.8 % ; P = .004 . Eighty percent of DVT occurred within the first 14 postoperative days . No severe side effects of LMWH were observed . Only 5 % of patients refused continued subcutaneous LMWH injections . CONCLUSIONS In patients undergoing ambulatory arthroscopic knee surgery without antithrombotic prophylaxis , the risk of DVT is high . Perioperative and postoperative prophylaxis with dalteparin is an effective and safe means of reducing this risk The purpose of this pilot study was to compare the effectiveness of conservative therapy involving medical exercise therapy ( MET ) versus arthroscopic surgery in patients with knee pain , with MRI-verified degenerative meniscus . The patients were r and omly assigned either to  MET ( n = 9 ) or to  arthroscopic surgery ( n = 8) . Patients receiving MET  had 3 treatments a week for 3 months , a total of 36 treatments . The arthroscopy consisted of meniscectomy with no structured conservative therapy after surgery . Assessment of pain , function , anxiety and depression were performed at inclusion and after 3 months . At the end of treatment , which was 3 months after inclusion , there were no statistical differences between the two groups regarding pain and function . However , anxiety and depression were significantly reduced in the MET group compared with the patients receiving arthroscopic surgery . Bearing in mind the low number of included patients in this pilot study , arthroscopy was found to be no better than MET regarding knee pain and overall daily function . The results from this pilot study are similar to other clinical studies , thereby demonstrating that conservative therapy is just as effective as surgery Background — Arthroscopic meniscal surgery is the most common orthopedic procedure , and the incidence has increased in Denmark over the last 10 years . Concomitantly , several r and omized controlled trials have shown no benefit of arthroscopic procedures including arthroscopic partial meniscectomy in middle-aged and older individuals suffering from knee pain with or without knee osteoarthritis . We examined the annual incidence of meniscal procedures together with age , sex , and diagnosis for patients who underwent meniscal procedures in the period 2000–2011 in Denmark . Methods — Data on age , sex , diagnosis , and surgical procedures were extracted from the Danish National Patient Register for the years 2000–2011 , for all records containing meniscal surgery as a primary or secondary procedure . Results — The overall annual incidence of meniscal procedures per 100,000 persons in Denmark doubled from 164 in 2000 to 312 in 2011 ( i.e. 8,750 procedures to 17,368 procedures ) . A 2-fold increase was found for patients aged between 35 and 55 , and a 3-fold increase was found for those older than 55 . Middle-aged and older patients accounted for 75 % of all 151,228 meniscal procedures carried out between 2000 and 2011 . Interpretation — The incidence of meniscal procedures performed in Denmark doubled from 2000 to 2011 , with the largest increase in middle-aged and older patients . This increase contrasts with the mounting evidence showing no added benefit of arthroscopic partial meniscectomy over non-surgical treatments . Our observations illustrate the long delay in the dissemination , acceptance , and implementation of research evidence into the practice of arthroscopic surgery Abstract This study examined the effect of four different methods for treating intrasubstance meniscal lesions . Forty patients ( 21 men , ¶19 women ; age 30.4 years , range 16–50 ) with an isolated and symptomatic painful horizontal grade 2 meniscal lesion on the medial side ( documented with MRI ) were included . Patients were r and omly assigned by the birth date to one of four treatment groups : group A , conservative therapy ( n = 12 ) ; group B , arthroscopic suture repair with access channels ( n = 10 ) ; group C , arthroscopic minimal central resection , intrameniscal fibrin clot and suture repair ( n = 7 ) ; and group D , arthroscopic partial meniscectomy ¶(n = 11 ) . The average length of follow-up was 26.5 months ( range 12–38 months ) . Follow-up evaluation consisted of clinical examination with the findings recorded according to the IKDC protocol , radiographs , and control MRI . Group A had 75 % normal or nearly normal final evaluation at follow-up , group B 90 % , group C 43 % , and group D 100 % normal or nearly normal at follow-up . These short-term results indicate that intrasubstance meniscal lesions can be treated best by performing partial meniscectomy . To preserve the important function of the meniscus , arthroscopic suture repair with access channels might give even better medium- to long-term results . Conservative treatment is often not satisfactory . Additionally , our findings show that MRI examinations are not superior to accurate clinical examinations Background : It is still debated whether a degenerative horizontal tear of the medial meniscus should be treated with surgery . Hypothesis : The clinical outcomes of arthroscopic meniscectomy will be better than those of nonoperative treatment for a degenerative horizontal tear of the medial meniscus . Study Design : R and omized controlled trial ; Level of evidence , 1 . Methods : A total of 102 patients with knee pain and a degenerative horizontal tear of the posterior horn of the medial meniscus on magnetic resonance imaging were included in this study between January 2007 and July 2009 . The study included 81 female and 21 male patients with an average age of 53.8 years ( range , 43 - 62 years ) . Fifty patients underwent arthroscopic meniscectomy ( meniscectomy group ) , and 52 patients underwent nonoperative treatment with strengthening exercises  ( nonoperative group ) . Functional outcomes were compared using a visual analog scale ( VAS ) for pain , Lysholm knee score , Tegner activity scale , and patient subjective knee pain and satisfaction . Radiological evaluations were performed using the Kellgren-Lawrence classification to evaluate osteoarthritic changes . Results : In terms of clinical outcomes , meniscectomy did not provide better functional improvement than nonoperative treatment . At the final follow-up , the average VAS scores were 1.8 ( range , 1 - 5 ) in the meniscectomy group and 1.7 ( range , 1 - 4 ) in the nonoperative group ( P = .675 ) . The average Lysholm knee scores at 2-year follow-up were 83.2 ( range , 52 - 100 ) and 84.3 ( range , 58 - 100 ) in the meniscectomy and nonoperative groups , respectively ( P = .237 ) . In addition , the average Tegner activity scale and subjective satisfaction scores were not significantly different between the 2 groups . Although most patients initially had intense knee pain with mechanical symptoms , both groups reported a relief in knee pain , improved knee function , and a high level of satisfaction with treatment ( P < .05 for all values ) . Two patients in the meniscectomy group and 3 in the nonoperative group with Kellgren-Lawrence grade 1 progressed to grade 2 at the 2-year follow-up . Conclusion : There were no significant differences between arthroscopic meniscectomy and nonoperative management with strengthening exercises in terms of relief in knee pain , improved knee function , or increased satisfaction in patients after 2 years of follow-up Here is an article analyzing some of the consequences of the 2 famous ( infamous ? ) r and omized vertebroplasty trials published in the New Engl and Journal of Medicine in August 2009 . Curiously , it is by some of the same authors . They looked at monthly referral patterns for nearly 
    Output:
    
CONCLUSIONS The small inconsequential benefit seen from interventions that include arthroscopy for the degenerative knee is limited in time and absent at one to two years after surgery .
Knee arthroscopy is associated with harms .
Taken together , these findings do not support the practise of arthroscopic surgery for middle aged or older patients with knee pain with or without signs of osteoarthritis .