***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: We describe the results of 50 operations carried out on 46 patients with medial osteoarthritis of the knee of Ahlbäck grade 1 to 3 . Patients were r and omised either to a closed-wedge high tibial osteotomy ( HTO ) or an open-wedge procedure based on the hemicallotasis technique ( HCO ) . Their median age was 55 years ( 38 to 68 ) . The preoperative median hip-knee-ankle ( HKA ) angle was 171 degrees ( 164 to 176 ) in the HTO group and 173 degrees ( 165 to 179 ) in the HCO group . After six weeks , the median HKA angle was 185 degrees ( 176 to 194 ) in the HTO group and 184 degrees ( 181 to 188 ) in the HCO group . In the HTO group , seven patients were within the range of 182 degrees to 186 degrees compared with 21 in the HCO group ( p < 0.001 ) . One year later , ten HTO patients were within this range while the HKA angulation in the HCO group was unchanged . At two years the numbers were 11 and 18 , respectively . We evaluated the clinical results on the Hospital for Special Surgery , Lysholm and Wallgren-Tegner activity scores , and patients completed part of the Nottingham Health Profile question naire . An impartial observer at the two-year follow-up concluded that all scores had improved , but found no clinical differences between the groups Background : Arthrosis is particularly prevalent in the knee . Infiltration treatment for gonarthrosis is among the most widely used techniques in orthopaedic practice . Purpose : To compare the clinical response of hyaluronic acid ( HA ) and platelet-rich plasma ( PRP ) treatment in 2 groups of patients affected by gonarthrosis . Study Design : R and omized controlled trial ; Level of evidence , 1 . Methods : A total of 120 patients affected by clinical ly and radiographically documented gonarthrosis were included in this study . The gonarthrosis was grade d using the Kellgren-Lawrence radiographic classification scale . The 120 patients were r and omized into 2 study groups in a 1:1 ratio : 60 patients received 4 intra-articular injections of PRP ( specifically , autologous conditioned plasma [ ACP ] , 5.5 mL ) , and 60 patients received 4 intra-articular injections of HA ( 20 mg/2 mL ) . An unblinded physician performed infiltration once a week for 4 weeks into the knee affected by clinical ly relevant gonarthrosis ( in both groups ) . All patients were evaluated with the Western Ontario and McMaster ( WOMAC ) score before the infiltration and at 4 , 12 , and 24 weeks after the first injection . Results : Treatment with a local injection of ACP had a significant effect shortly after the final infiltration and a continuously improving sustained effect up to 24 weeks ( WOMAC score , 65.1 and 36.5 in the HA and ACP groups , respectively ; P < .001 ) , where the clinical outcomes were better compared with the results with HA . In the HA group , the worst results were obtained for grade III gonarthrosis , whereas the clinical results obtained in the ACP group did not show any statistically significant difference in terms of the grade of gonarthrosis . The mean WOMAC scores for grade III gonarthrosis were 74.85 in the HA group and 41.20 in the ACP group ( P < .001 ) . Conclusion : Treatment with ACP showed a significantly better clinical outcome than did treatment with HA , with sustained lower WOMAC scores . Treatment with HA did not seem to be effective in the patients with grade III gonarthrosis Background Bisphosphonates increase the callus size and strength in animal fracture studies . In a human non-r and omized pilot study of high tibial osteotomies in knee osteoarthritis , using the hemicallotasis ( HCO ) technique , bisphosphonates shortened the healing time by 12 days . In the present r and omized study , we wanted to determine whether a single infusion of zoledronic acid reduces the time to clinical osteotomy healing . Results from the same trial , showing improved pin fixation with zoledronate , have been published separately . Methods 46 consecutive patients ( aged 35–65 years ) were operated . At 4 weeks postoperatively , the patients were r and omized to an intravenous infusion of either zoledronic acid or sodium chloride . Dual-energy X-ray absorptiometry ( DEXA ) was performed 10 weeks postoperatively . Radiographs were taken at 10 weeks and every second week until there was radiographic and clinical healing . Healing was evaluated blind , with extraction of the external fixator as the endpoint . At 1.5 years , an additional radiograph was taken and the hip-knee-ankle ( HKA ) angle measured to evaluate whether correction had been retained . Results All osteotomies healed with no difference in healing time between the groups ( 77 ( SD 7 ) days ) . Bone mineral density and bone mineral content , as assessed with DEXA , were similar between the groups . Radiographically , both groups had retained the acquired correction at the 1.5-year follow-up . Interpretation In this r and omized comparison , a single infusion of zoledronic acid increased the pin fixation of the external frame but did not shorten the healing time . In both groups , the external fixator was extracted almost 2 weeks earlier than in previous studies . The early extraction did not cause a loss of correction in either group Background Obesity is an important risk factor for knee osteoarthritis ( OA ) , Weight loss can reduce the symptoms of knee OA . No prospect i ve studies assessing the impact of weight loss on knee cartilage structure and composition have been performed . Objectives To assess the impact of weight loss on knee cartilage thickness and composition . Methods 111 obese adults were recruited from either laparoscopic adjustable gastric b and ing or exercise and diet weight loss programmes from two tertiary centres .  MRI was performed at baseline and 12-month follow-up to assess cartilage thickness . 78 eligible subjects also underwent delayed gadolinium-enhanced MRI of cartilage ( dGEMRIC ) , an estimate of proteoglycan content . The associations between cartilage outcomes ( cartilage thickness and dGEMRIC index ) and weight loss were adjusted for age , gender , body mass index ( BMI ) and presence of clinical knee OA . Results Mean age was 51.7±11.8 years and mean BMI was 36.6±5.8 kg/m2 ; 32 % had clinical knee OA . Mean weight loss was 9.3±11.9 % . Percentage weight loss was negatively associated with cartilage thickness loss in the medial femoral compartment in multiple regression analysis ( β=0.006 , r2=0.19 , p=0.029 ) . This association was not detected in the lateral compartment ( r2=0.12 , p=0.745 ) . Percentage weight loss was associated with an increase in medial dGEMRIC in multiple regression analysis ( β=3.9 , r2=0.26 ; p=0.008 ) but not the lateral compartment ( r2=0.14 , p=0.34 ) . For every 10 % weight loss there was a gain in the medial dGEMRIC index of 39 ms ( r2=0.28 ; p=0.014 ) . The lowest weight loss cut-off associated with reduced medial femoral cartilage thickness loss and improved medial dGEMRIC index was 7 % . Conclusions Weight loss is associated with improvements in the quality ( increased proteoglycan content ) and quantity ( reduced cartilage thickness losses ) of medial articular cartilage . This was not observed in the lateral compartment . This could ultimately lead to a reduced need for total joint replacements and is thus a finding with important public health implication OBJECTIVE Although knee malalignment is assumed to correlate with knee osteoarthritis ( OA ) , it is still unknown whether malalignment precedes the development of OA or whether it is a result of OA . The aim of this study was to assess the relationship between malalignment and the development of knee OA as well as progression of knee OA . METHODS A total of 1,501 participants in the Rotterdam study were r and omly selected .  Knee OA at baseline and at followup ( mean followup 6.6 years ) was scored according to the Kellgren/Lawrence ( K/L ) grading system . Alignment was measured by the femorotibial angle on radiographs at baseline . Multivariable logistic regression for repeated measurements was used to analyze the association of malalignment with the development and progression of OA . RESULTS Of 2,664 knees , 1,012 ( 38 % ) were considered to have normal alignment , 693 ( 26 % ) had varus alignment , and 959 ( 36 % ) had valgus alignment . A comparison of valgus alignment and normal alignment showed that valgus alignment was associated with a borderline significant increase in development of knee OA ( odds ratio [ OR ] 1.54 , 95 % confidence interval [ 95 % CI ] 0.97 - 2.44 ) , and varus alignment was associated with a 2-fold increased risk ( OR 2.06 , 95 % CI 1.28 - 3.32 ) . Stratification for body mass index showed that this increased risk was especially seen in overweight and obese individuals but not in non-overweight persons . The risk of OA progression was also significantly increased in the group with varus alignment compared with the group with normal alignment ( OR 2.90 , 95 % CI 1.07 - 7.88 ) . CONCLUSION An increasing degree of varus alignment is associated not only with progression of knee OA but also with development of knee OA . However , this association seems particularly applicable to overweight and obese persons Medial opening-wedge has gained popularity in comparison to other techniques of high tibial osteotomy . This technique involves the creation of a gap in the tibia . Filling the gap with autologous iliac bone graft was recommended in the classic description , to prevent complications such as correction loss or delayed bone union . No previous reports have compared grafted and nongrafted osteotomies . This study hypothesized that the use of autologous bone graft in medial opening-wedge high tibial osteotomy ( MOWHTO ) less than 12.5 mm is unnecessary . A prospect i ve r and omized clinical trial was conducted . Forty-six opening-wedge high tibial osteotomies were carried out between April 2007 and December 2008 . All had fixation with a type of Puddu stainless steel plate and screws . Patients were r and omly divided by software analysis into two groups : group A had osteotomies that were filled with autologous bone graft and group B had osteotomies that were unfilled . Autologous iliac bone graft was harvested in both groups . Clinical and radiographic evaluations were performed twice monthly by blinded investigators . The rates of complications were compared between the groups . There was no difference in demographic data . Mean time to clinical bone union in group A was 12.4 weeks ( confidence interval [ CI ] 11.2 - 13.6 ) and in group B was 13.7 weeks ( CI 12.5 - 14.9 ) , but this difference was not significant ( P = 0.13 ) . Signals of correction loss occurred in one patient ( 4.35 % ) in group A , and in two patients ( 8.70 % ) in group B. All osteotomies had achieved bone union . It was concluded that time to bone union was not statistically different between the group with bone graft and the group without graft CONTEXT Knee osteoarthritis ( OA ) is a leading cause of disability in older persons . Few risk factors for disease progression or functional decline have been identified . Hip-knee-ankle alignment influences load distribution at the knee ; varus and valgus alignment increase medial and lateral load , respectively . OBJECTIVE To test the hypotheses that ( 1 ) varus alignment increases risk of medial knee OA progression during the subsequent 18 months , ( 2 ) valgus alignment increases risk of subsequent lateral knee OA progression , ( 3 ) greater severity of malalignment is associated with greater subsequent loss of joint space , and ( 4 ) greater burden of malalignment is associated with greater subsequent decline in physical function . DESIGN AND SETTING Prospect i ve longitudinal cohort study conducted March 1997 to March 2000 at an academic medical center in Chicago , Ill. PARTICIPANTS A total of 237 persons recruited from the community with primary knee OA , defined by presence of definite tibiofemoral osteophytes and at least some difficulty with knee-requiring activity ; 230 ( 97 % ) completed the study . MAIN OUTCOME MEASURES Progression of OA , defined as a 1- grade increase in severity of joint space narrowing on semiflexed , fluoroscopically confirmed knee radiographs ; change in narrowest joint space width ; and change in physical function between baseline and 18 months , compared by knee alignment at baseline . RESULTS Varus alignment at baseline was associated with a 4-fold increase in the odds of medial progression , adjusting for age , sex , and body mass index ( adjusted odds ratio [ OR ] , 4.09 ; 95 % confidence interval [ CI ] , 2.20 - 7.62 ) . Valgus alignment at baseline was associated with a nearly 5-fold increase in the odds of lateral progression ( adjusted OR , 4.89 ; 95 % CI , 
    Output:
    
Follow-up of studies comparing different osteotomy techniques was too short to measure treatment failure , which implicates revision to a knee arthroplasty .
The conclusion of this up date did not change : Valgus high tibial osteotomy  reduces pain and improves knee function in patients with medial compartmental osteoarthritis of the knee .
However , this conclusion is based on within-group comparisons , not on non-operative controls .
No evidence suggests differences between different osteotomy techniques .
No evidence shows whether an osteotomy is more effective than alternative surgical treatment such as unicompartmental knee replacement or non-operative treatment .
So far , the results of this up date d review do not justify a conclusion on benefit of specific high tibial osteotomy technique for knee osteoarthritis