human
***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 Meniscal substitutes have been suggested for the treatment of knee pain  after partial meniscectomy . However , despite the partial nature of the initial meniscectomy , secondary extrusion of the substitute is common . The primary objective of this study was to evaluate morphological outcomes of meniscal substitute implantation and their potential associations with preoperative meniscal extrusion . HYPOTHESIS Preoperative absolute meniscal extrusion in the coronal plane predicts poorer morphological and clinical outcomes . MATERIAL AND METHODS Consecutive patients who received an Actifit ( ® ) meniscal substitute between 2008 and 2011 were included prospect ively . After 1 year and 2 years , the IKDC score and KOOS were determined and magnetic resonance imaging performed . The morphological evaluation consisted in measuring meniscal extrusion and cartilage coverage by the substitute in the coronal and sagittal planes . RESULTS Twenty patients were included . Among them , 3 required subsequent removal of the substitute . The mean subjective IKDC score increased from 48.1 preoperatively to 56.4 after 2 years . Over the same period , the function/sports/recreational activities component of the KOOS improved significantly ( 42.9 vs. 55.0 , P=0.04 ) . Positive correlations between preoperative and 1-year values were demonstrated for both cartilage coverage in the coronal and the sagittal planes ( P=0.03 and P=0.04 , respectively ) and coronal absolute meniscal extrusion ( P=0.05 ) . No significant differences were found between preoperative and 2-year values of cartilage coverage in the coronal and sagittal planes ( P=0.38 ) . There was a negative correlation linking preoperative meniscal extrusion in the coronal plane to 1-year cartilage coverage in the coronal and sagittal planes ( P=0.01 and P=0.04 , respectively ) . Preoperative absolute meniscal extrusion in the coronal plane correlated negatively with the subjective IKDC score after 1 year ( P=0.02 ) . DISCUSSION Preoperative meniscal extrusion in the coronal plane strongly predicts clinical and morphological outcomes . Marked preoperative meniscal extrusion , even in a patient with symptoms after partial meniscectomy , should prompt an appraisal of whether allograft replacement may be more appropriate than a meniscal substitute . LEVEL OF EVIDENCE IV , prospect i ve study BACKGROUND Loss of meniscal tissue leads to increased pain and decreased clinical function and activity levels . We hypothesized that patients receiving a collagen meniscus implant would have better clinical outcomes than patients treated with partial medial meniscectomy alone . METHODS Three hundred and eleven patients with an irreparable injury of the medial meniscus or a previous partial medial meniscectomy , treated by a total of twenty-six surgeon-investigators at sixteen sites , were enrolled in the study . There were two study arms , one consisting of 157 patients who had had no prior surgery on the involved meniscus ( the " acute " arm of the study ) and one consisting of 154 patients who had had one , two , or three prior meniscal surgical procedures ( the " chronic " arm ) . Patients were r and omized either to receive the collagen meniscus implant or to serve as a control subject treated with a partial meniscectomy only . Patients underwent frequent clinical follow-up examinations over two years and completed vali date d outcomes question naires over seven years . The patients who had received a collagen meniscus implant were required by protocol to have second-look arthroscopy at one year to determine the amount of new tissue growth and to perform a biopsy to assess tissue quality . Reoperation and survival rates were determined . RESULTS In the acute group , seventy-five patients received a collagen meniscus implant and eighty-two were controls . In the chronic group , eighty-five patients received the implant and sixty-nine were controls . The mean duration of follow-up was fifty-nine months ( range , sixteen to ninety-two months ) . The 141 repeat arthroscopies done at one year showed that the collagen meniscus implants had result ed in significantly ( p = 0.001 ) increased meniscal tissue compared with that seen after the original index partial meniscectomy . The implant supported meniscus-like matrix production and integration as it was assimilated and resorbed . In the chronic group , the patients who had received an implant regained significantly more of their lost activity than did the controls ( p = 0.02 ) and they underwent significantly fewer non- protocol reoperations ( p = 0.04 ) . No differences were detected between the two treatment groups in the acute arm of the study . CONCLUSIONS New biomechanically competent meniscus-like tissue forms after placement of a collagen meniscus implant , and use of the implant appears safe . The collagen meniscus implant supports new tissue ingrowth that appears to be adequate to enhance meniscal function as evidence d by improved clinical outcomes in patients with a chronic meniscal injury . The collagen meniscus implant has the utility to be used to replace irreparable or lost meniscal tissue in patients with a chronic meniscal injury . The implant was not found to have any benefit for patients with an acute injury PURPOSE In this feasibility study , a 5- to 6-year clinical follow-up evaluation was conducted on 8 patients who had undergone reconstruction of 1 injured medial meniscus with a tissue-engineered collagen meniscus implant .  The hypothesis was that these patients would show significant clinical improvement over their preoperative status and would have maintained their status determined at the 2-year follow-up evaluation . TYPE OF STUDY Prospect i ve longitudinal feasibility study follow-up evaluation . METHODS Eight patients underwent arthroscopic placement of a collagen meniscus implant by a single surgeon to reconstruct and restore the irreparably damaged medial meniscus of 1 knee . All patients returned for clinical , radiographic , magnetic resonance imaging , and arthroscopic examinations an average of 5.8 years ( range , 5.5 - 6.3 y ) after collagen meniscus implant placement .  RESULTS Lysholm scores improved significantly ( P = .045 ) from 75 preoperatively to 88 at most recent follow-up evaluation . Average Tegner activity scores improved significantly ( P = .001 ) from 3 to 6 . Patient self- assessment improved significantly ( P = .046 ) from 2.4 to 1.9 ( 1 = normal , 4 = severely abnormal ) . Pain scores improved from 23 to 11 ( 0 = no pain , 100 = worst pain ) . Imaging studies confirmed that the chondral surfaces of the medial compartment had not degenerated further since the placement of the implant 5.8 years earlier . Relook arthroscopy with direct measurement of the newly generated tissue revealed 69 % defect filling . Histologic assessment of tissue biopsy specimens from 3 patients showed the presence of fibrocartilage with a uniform extracellular matrix . CONCLUSIONS The meniscus-like tissue that developed after collagen meniscus implant placement has maintained its structure and functioned without negative effects for more than 5 years . The hypothesis was affirmed that these patients were improved significantly compared with their preoperative status and unchanged compared with 2-year evaluations . LEVEL OF EVIDENCE Level IV Objective : Replacement of an almost completely absent medial meniscus with a collagen implant ( CMI ) , reconstruction of form and function of the medial meniscus , delay of the development of arthrosis deformans . Indications : Subtotal degenerative or traumatic loss of the medial meniscus , stable meniscal periphery , stable anterior and posterior meniscal insertions , joint with stable ligaments . Contraindications : Complete loss of the medial meniscus . Untreated knee ligament instability . Extreme varus deformity . Extensive cartilaginous damage , i.e. , levels IV and VI as described by Bauer and Jackson . Advanced unicompartmental or generalized arthrosis . Replacement of the lateral meniscus . Surgical Technique : St and ard anterior arthroscopy portals . Resection of the medial meniscus leaving a complete and stable outer rim . Revitalization of the periphery to promote healing . Measurement of defect size . Insertion and fixation of the CMI with nonresorbable suture material in inside-out technique . Postoperative Management : Postoperative knee brace with limited motion in extension/flexion of 0/0/60 ° until week 4 , 0/0/90 ° until week 6 . Coutinuous passive motion within the limits of motion from the 1st postoperative day , actively assisted physiotherapy . No weight bearing for 6 weeks , then increased weight bearing for 2 weeks until full weight bearing is achieved . Cycling can commence from 3 months postoperatively . Full sporting activity after 6 months . Results : 60 patients ( 19–68 years , average 41.6 years ) with subtotal loss of the medial meniscus and varus morphotype were treated from January 2001 to May 2004 as part of a prospect i ve , r and omized , arthroscopically controlled study . The sample consisted of 30 patients with high tibial valgus osteotomy combined with implantation of a CMI , and 30 patients with valgization correction osteotomy only . The CMI had to be removed from one patient because of a dislocation . Evaluation on the Lysholm Score , IKDC ( International Knee Documentation Committee ) , and subjective pain data revealed only slight , nonsignificant differences for 39 patients after 24 months ( CMI and correction n = 23 ; correction only n = 16 ) . The chondroprotective effect of the CMI in the long term remains to be seen Abstract Purpose The aim of the study was to determine whether medial meniscal substitution with a polyurethane scaffold ( Actifit ® ) improves the outcome of medial meniscal-deficient varus knees undergoing open-wedge high tibial osteotomy . Methods Sixty patients with symptomatic varus knees those who underwent open-wedge high tibial osteotomies were prospect ively studied . In 30 patients , the medial meniscus was left with a defect larger than 25 mm ( Group M ) . An Actifit ® device was implanted ( Group A ) in the remaining 30 patients . Patients were functionally evaluated with WOMET , IKDC and VAS . Patient satisfaction was grade d from 0 ( not satisfied ) to 4 ( very satisfied ) . Results Both groups were comparable preoperatively . They had similar follow-up periods ( 31.2 months ; range 24–47.5 ; n.s . ) . WOMET improved a mean of 53.4 ± 8.4 and 42.4 ± 17.2 points in Groups M and A , respectively ( p = 0.002 ) . IKDC improved a mean of 56.7 ± 12 and 50.3 ± 15.6 points in Groups M and A , respectively ( n.s . ) . VAS dropped 5.9 ± 2.1 and 4.7 ± 2.8 points in Groups M and A , respectively ( p = 0.006 ) . Patient satisfaction averaged 3.3 ± 0.8 and 3.3 ± 1 in Groups M and A , respectively ( n.s . ) . Conclusions Patients with symptomatic varus knees were treated with open-wedge high tibial osteotomies , and a meniscectomy was improved more at short-term follow-up in most of the evaluated functional scores than those patients with concomitant implantation of a medial Actifit ® implant . However , there was no difference in terms of patient satisfaction with the procedure . Based on the short-term functional results of this study , no data were provided to support medial meniscal substitution with a polyurethane scaffold when an open-wedge high tibial osteotomy is being performed . Level of evidence Prospect i ve comparative study , Level II Purpose The aim of this study is to evaluate the safety and clinical efficacy of this novel polyurethane meniscal scaffold to treat partial meniscal loss . Methods Eighteen patients ( 11 men and 7 women , mean age : 45 years ) affected by irreparable acute meniscal tears requiring partial meniscectomy or chronic prior loss of meniscal tissue were enrolled in the study . They underwent arthroscopic polyurethane meniscal scaffold implantation ( 13 medial and 5 lateral ) and , in case of presence of other comorbidities , concurrent procedures were also performed . Patients were prospect ively evaluated up to 2 years of follow-up through IKDC objective , IKDC subjective , and Tegner scores . Furthermore , MRI evaluation of the meniscal scaffold was performed . Results No major adverse events were observed . A statistically significant increase in all the clinical parameters considered was found . The IKDC objective score increased from 61 % of normal or nearly normal knees at basal evaluation to 94 % at 2 years of follow-up ( p = 0.01 ) . There was also a significant increase in the IKDC subjective score both at 6–12 months of follow-up ( p = 0.03 and p < 0.005 ) , which was confirmed at 24 months . The Tegner score also showed a significant increase from the pre-operative level ( median value 2 , range 1–5 ) to final evaluation ( median value 3 , range 2–5 ; p = 0.005 ) , albeit not reaching the pre-injury sports activity level . Conclusions The implantation of this novel polyurethane scaffold proved to be a safe and potentially effective procedure to treat partial meniscal loss with encouraging results at short-term follow-up . Further high- quality studies with larger numbers of patients and longer evaluation times are needed to confirm these preliminary data .Level 
    Output:
    
agent
***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 Meniscal substitutes have been suggested for the treatment of knee pain  after partial meniscectomy . However , despite the partial nature of the initial meniscectomy , secondary extrusion of the substitute is common . The primary objective of this study was to evaluate morphological outcomes of meniscal substitute implantation and their potential associations with preoperative meniscal extrusion . HYPOTHESIS Preoperative absolute meniscal extrusion in the coronal plane predicts poorer morphological and clinical outcomes . MATERIAL AND METHODS Consecutive patients who received an Actifit ( ® ) meniscal substitute between 2008 and 2011 were included prospect ively . After 1 year and 2 years , the IKDC score and KOOS were determined and magnetic resonance imaging performed . The morphological evaluation consisted in measuring meniscal extrusion and cartilage coverage by the substitute in the coronal and sagittal planes . RESULTS Twenty patients were included . Among them , 3 required subsequent removal of the substitute . The mean subjective IKDC score increased from 48.1 preoperatively to 56.4 after 2 years . Over the same period , the function/sports/recreational activities component of the KOOS improved significantly ( 42.9 vs. 55.0 , P=0.04 ) . Positive correlations between preoperative and 1-year values were demonstrated for both cartilage coverage in the coronal and the sagittal planes ( P=0.03 and P=0.04 , respectively ) and coronal absolute meniscal extrusion ( P=0.05 ) . No significant differences were found between preoperative and 2-year values of cartilage coverage in the coronal and sagittal planes ( P=0.38 ) . There was a negative correlation linking preoperative meniscal extrusion in the coronal plane to 1-year cartilage coverage in the coronal and sagittal planes ( P=0.01 and P=0.04 , respectively ) . Preoperative absolute meniscal extrusion in the coronal plane correlated negatively with the subjective IKDC score after 1 year ( P=0.02 ) . DISCUSSION Preoperative meniscal extrusion in the coronal plane strongly predicts clinical and morphological outcomes . Marked preoperative meniscal extrusion , even in a patient with symptoms after partial meniscectomy , should prompt an appraisal of whether allograft replacement may be more appropriate than a meniscal substitute . LEVEL OF EVIDENCE IV , prospect i ve study BACKGROUND Loss of meniscal tissue leads to increased pain and decreased clinical function and activity levels . We hypothesized that patients receiving a collagen meniscus implant would have better clinical outcomes than patients treated with partial medial meniscectomy alone . METHODS Three hundred and eleven patients with an irreparable injury of the medial meniscus or a previous partial medial meniscectomy , treated by a total of twenty-six surgeon-investigators at sixteen sites , were enrolled in the study . There were two study arms , one consisting of 157 patients who had had no prior surgery on the involved meniscus ( the " acute " arm of the study ) and one consisting of 154 patients who had had one , two , or three prior meniscal surgical procedures ( the " chronic " arm ) . Patients were r and omized either to receive the collagen meniscus implant or to serve as a control subject treated with a partial meniscectomy only . Patients underwent frequent clinical follow-up examinations over two years and completed vali date d outcomes question naires over seven years . The patients who had received a collagen meniscus implant were required by protocol to have second-look arthroscopy at one year to determine the amount of new tissue growth and to perform a biopsy to assess tissue quality . Reoperation and survival rates were determined . RESULTS In the acute group , seventy-five patients received a collagen meniscus implant and eighty-two were controls . In the chronic group , eighty-five patients received the implant and sixty-nine were controls . The mean duration of follow-up was fifty-nine months ( range , sixteen to ninety-two months ) . The 141 repeat arthroscopies done at one year showed that the collagen meniscus implants had result ed in significantly ( p = 0.001 ) increased meniscal tissue compared with that seen after the original index partial meniscectomy . The implant supported meniscus-like matrix production and integration as it was assimilated and resorbed . In the chronic group , the patients who had received an implant regained significantly more of their lost activity than did the controls ( p = 0.02 ) and they underwent significantly fewer non- protocol reoperations ( p = 0.04 ) . No differences were detected between the two treatment groups in the acute arm of the study . CONCLUSIONS New biomechanically competent meniscus-like tissue forms after placement of a collagen meniscus implant , and use of the implant appears safe . The collagen meniscus implant supports new tissue ingrowth that appears to be adequate to enhance meniscal function as evidence d by improved clinical outcomes in patients with a chronic meniscal injury . The collagen meniscus implant has the utility to be used to replace irreparable or lost meniscal tissue in patients with a chronic meniscal injury . The implant was not found to have any benefit for patients with an acute injury PURPOSE In this feasibility study , a 5- to 6-year clinical follow-up evaluation was conducted on 8 patients who had undergone reconstruction of 1 injured medial meniscus with a tissue-engineered collagen meniscus implant .  The hypothesis was that these patients would show significant clinical improvement over their preoperative status and would have maintained their status determined at the 2-year follow-up evaluation . TYPE OF STUDY Prospect i ve longitudinal feasibility study follow-up evaluation . METHODS Eight patients underwent arthroscopic placement of a collagen meniscus implant by a single surgeon to reconstruct and restore the irreparably damaged medial meniscus of 1 knee . All patients returned for clinical , radiographic , magnetic resonance imaging , and arthroscopic examinations an average of 5.8 years ( range , 5.5 - 6.3 y ) after collagen meniscus implant placement .  RESULTS Lysholm scores improved significantly ( P = .045 ) from 75 preoperatively to 88 at most recent follow-up evaluation . Average Tegner activity scores improved significantly ( P = .001 ) from 3 to 6 . Patient self- assessment improved significantly ( P = .046 ) from 2.4 to 1.9 ( 1 = normal , 4 = severely abnormal ) . Pain scores improved from 23 to 11 ( 0 = no pain , 100 = worst pain ) . Imaging studies confirmed that the chondral surfaces of the medial compartment had not degenerated further since the placement of the implant 5.8 years earlier . Relook arthroscopy with direct measurement of the newly generated tissue revealed 69 % defect filling . Histologic assessment of tissue biopsy specimens from 3 patients showed the presence of fibrocartilage with a uniform extracellular matrix . CONCLUSIONS The meniscus-like tissue that developed after collagen meniscus implant placement has maintained its structure and functioned without negative effects for more than 5 years . The hypothesis was affirmed that these patients were improved significantly compared with their preoperative status and unchanged compared with 2-year evaluations . LEVEL OF EVIDENCE Level IV Objective : Replacement of an almost completely absent medial meniscus with a collagen implant ( CMI ) , reconstruction of form and function of the medial meniscus , delay of the development of arthrosis deformans . Indications : Subtotal degenerative or traumatic loss of the medial meniscus , stable meniscal periphery , stable anterior and posterior meniscal insertions , joint with stable ligaments . Contraindications : Complete loss of the medial meniscus . Untreated knee ligament instability . Extreme varus deformity . Extensive cartilaginous damage , i.e. , levels IV and VI as described by Bauer and Jackson . Advanced unicompartmental or generalized arthrosis . Replacement of the lateral meniscus . Surgical Technique : St and ard anterior arthroscopy portals . Resection of the medial meniscus leaving a complete and stable outer rim . Revitalization of the periphery to promote healing . Measurement of defect size . Insertion and fixation of the CMI with nonresorbable suture material in inside-out technique . Postoperative Management : Postoperative knee brace with limited motion in extension/flexion of 0/0/60 ° until week 4 , 0/0/90 ° until week 6 . Coutinuous passive motion within the limits of motion from the 1st postoperative day , actively assisted physiotherapy . No weight bearing for 6 weeks , then increased weight bearing for 2 weeks until full weight bearing is achieved . Cycling can commence from 3 months postoperatively . Full sporting activity after 6 months . Results : 60 patients ( 19–68 years , average 41.6 years ) with subtotal loss of the medial meniscus and varus morphotype were treated from January 2001 to May 2004 as part of a prospect i ve , r and omized , arthroscopically controlled study . The sample consisted of 30 patients with high tibial valgus osteotomy combined with implantation of a CMI , and 30 patients with valgization correction osteotomy only . The CMI had to be removed from one patient because of a dislocation . Evaluation on the Lysholm Score , IKDC ( International Knee Documentation Committee ) , and subjective pain data revealed only slight , nonsignificant differences for 39 patients after 24 months ( CMI and correction n = 23 ; correction only n = 16 ) . The chondroprotective effect of the CMI in the long term remains to be seen Abstract Purpose The aim of the study was to determine whether medial meniscal substitution with a polyurethane scaffold ( Actifit ® ) improves the outcome of medial meniscal-deficient varus knees undergoing open-wedge high tibial osteotomy . Methods Sixty patients with symptomatic varus knees those who underwent open-wedge high tibial osteotomies were prospect ively studied . In 30 patients , the medial meniscus was left with a defect larger than 25 mm ( Group M ) . An Actifit ® device was implanted ( Group A ) in the remaining 30 patients . Patients were functionally evaluated with WOMET , IKDC and VAS . Patient satisfaction was grade d from 0 ( not satisfied ) to 4 ( very satisfied ) . Results Both groups were comparable preoperatively . They had similar follow-up periods ( 31.2 months ; range 24–47.5 ; n.s . ) . WOMET improved a mean of 53.4 ± 8.4 and 42.4 ± 17.2 points in Groups M and A , respectively ( p = 0.002 ) . IKDC improved a mean of 56.7 ± 12 and 50.3 ± 15.6 points in Groups M and A , respectively ( n.s . ) . VAS dropped 5.9 ± 2.1 and 4.7 ± 2.8 points in Groups M and A , respectively ( p = 0.006 ) . Patient satisfaction averaged 3.3 ± 0.8 and 3.3 ± 1 in Groups M and A , respectively ( n.s . ) . Conclusions Patients with symptomatic varus knees were treated with open-wedge high tibial osteotomies , and a meniscectomy was improved more at short-term follow-up in most of the evaluated functional scores than those patients with concomitant implantation of a medial Actifit ® implant . However , there was no difference in terms of patient satisfaction with the procedure . Based on the short-term functional results of this study , no data were provided to support medial meniscal substitution with a polyurethane scaffold when an open-wedge high tibial osteotomy is being performed . Level of evidence Prospect i ve comparative study , Level II Purpose The aim of this study is to evaluate the safety and clinical efficacy of this novel polyurethane meniscal scaffold to treat partial meniscal loss . Methods Eighteen patients ( 11 men and 7 women , mean age : 45 years ) affected by irreparable acute meniscal tears requiring partial meniscectomy or chronic prior loss of meniscal tissue were enrolled in the study . They underwent arthroscopic polyurethane meniscal scaffold implantation ( 13 medial and 5 lateral ) and , in case of presence of other comorbidities , concurrent procedures were also performed . Patients were prospect ively evaluated up to 2 years of follow-up through IKDC objective , IKDC subjective , and Tegner scores . Furthermore , MRI evaluation of the meniscal scaffold was performed . Results No major adverse events were observed . A statistically significant increase in all the clinical parameters considered was found . The IKDC objective score increased from 61 % of normal or nearly normal knees at basal evaluation to 94 % at 2 years of follow-up ( p = 0.01 ) . There was also a significant increase in the IKDC subjective score both at 6–12 months of follow-up ( p = 0.03 and p < 0.005 ) , which was confirmed at 24 months . The Tegner score also showed a significant increase from the pre-operative level ( median value 2 , range 1–5 ) to final evaluation ( median value 3 , range 2–5 ; p = 0.005 ) , albeit not reaching the pre-injury sports activity level . Conclusions The implantation of this novel polyurethane scaffold proved to be a safe and potentially effective procedure to treat partial meniscal loss with encouraging results at short-term follow-up . Further high- quality studies with larger numbers of patients and longer evaluation times are needed to confirm these preliminary data .Level 
    Output:
    