Actifit® scaffold implantation: Influence of preoperative meniscal extrusion on morphological and clinical outcomes. Comparison of the collagen meniscus implant with partial meniscectomy. A prospective randomized trial. Tissue-engineered collagen meniscus implants: 5- to 6-year feasibility study results. Replacement of the Meniscus with a Collagen Implant (CMI) Partial meniscus substitution with a polyurethane scaffold does not improve outcome after an open-wedge high tibial osteotomy Biodegradable polyurethane meniscal scaffold for isolated partial lesions or as combined procedure for knees with multiple comorbidities: clinical results at 2 years Treatment of Painful, Irreparable Partial Meniscal Defects With a Polyurethane Scaffold Polyurethane-based cell-free scaffold for the treatment of painful partial meniscus loss Open-wedge high tibial osteotomy: comparison between manual and computer-assisted techniques [Results of polyurethane implant for persistent knee pain after partial meniscectomy with a minimum of two years follow-up]. Prospective Long-Term Outcomes of the Medial Collagen Meniscus Implant Versus Partial Medial Meniscectomy Polyurethane scaffold in lateral meniscus segmental defects: clinical outcomes at 24 months follow-up. A clinical study of collagen meniscus implants to restore the injured meniscus. Tissue Ingrowth After Implantation of a Novel, Biodegradable Polyurethane Scaffold for Treatment of Partial Meniscal Lesions Successful Treatment of Painful Irreparable Partial Meniscal Defects With a Polyurethane Scaffold
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 of evidence Case series , Level IV Background : A biodegradable polyurethane scaffold was design ed to fulfill a challenging clinical need in the treatment of patients with painful , irreparable partial meniscal defects . Hypothesis : The use of an acellular polyurethane scaffold for new tissue generation in irreparable , partial meniscal defects provides both midterm pain relief and improved functionality . Study Design : Case series ; Level of evidence , 4 . Methods : A total of 44 patients with irreparable , partial meniscal defects ( 29 medial and 15 lateral ) were implanted with a polyurethane scaffold in a prospect i ve , single-arm proof-of-principle study with a minimum 5-year follow-up . Clinical outcomes were measured with the visual analog scale ( VAS ) for pain , International Knee Documentation Committee ( IKDC ) , and Knee injury and Osteoarthritis Outcome Score ( KOOS ) at baseline and at 2- and 5-year follow-up . Magnetic resonance imaging ( MRI ) was used to evaluate the meniscal implant and cartilage status of the index compartment . Kaplan-Meier time-to – treatment failure distributions were also performed . Removal of the scaffold , conversion to a meniscal transplant , or unicompartmental/total knee arthroplasty was used as endpoints . Results : Seven patients were lost to follow-up ( 15.9 % ) . The patients who participated in this study showed significant clinical improvement after surgery ( mean [ ±SD ] at baseline , 2 years , and 5 years : 56.2 ± 21.6 , 24.6 ± 22.7 , and 19.3 ± 26.9 , respectively [ VAS ] ; 206.5 ± 79.7 , 329.8 ± 108.9 , and 333.6 ± 112.2 , respectively [ total KOOS ] ) . MRI of the scaffolds showed a smaller sized implant when compared with the native meniscus with an irregular surface at 2- and 5-year follow-up . A stable cartilage status of the index compartment at 5-year follow-up was demonstrated in 46.7 % of patients compared with the baseline status . During the follow-up period , 62.2 % of the implants survived . At final follow-up , 66.7 % of the medial scaffolds were still functioning versus 53.8 % of the lateral scaffolds . Conclusion : A polyurethane meniscal implant can improve knee joint function and significantly reduce pain in patients with segmental meniscus deficiency up to 5 years after implantation . A stable cartilage status of the index compartment at 5-year follow-up was demonstrated in 46.7 % of patients , calling into question the chondroprotective ability of the implant . In addition , a relatively high failure rate was noticed . Long-term and r and omized controlled studies are m and atory to confirm the initial results and the reliability of this procedure Purpose The aim of this study was to document , at mid-term follow-up , the clinical and MRI outcome of a polyurethane-based cell-free scaffold implanted to treat painful partial meniscus loss . Methods Eighteen consecutive patients were enrolled and treated with arthroscopic polyurethane meniscal scaffold implantation and , in case of other comorbidities , with concurrent surgical procedures : 16 patients ( 9 men and 7 women , mean age 45 ± 13 years , mean BMI 25 ± 3 , 12 medial and 4 lateral implants ) were prospect ively evaluated with the subjective and objective IKDC and the Tegner scores at 24 , 36 , 48 , 60 , and 72 months of follow-up . Eleven patients were also evaluated by 1.5-T MRI at the final follow-up . Results The IKDC subjective score showed a significant improvement from baseline to 24 months ( 45.6 ± 17.5 and 75.3 ± 14.8 , respectively ; p = 0.02 ) and subsequent stable results over time for up to 72 months ( final score 75.0 ± 16.8 ) . The Tegner score improvement between pre-operative status and final follow-up was also significant ( p = 0.039 ) . Nevertheless , the final score remained significantly lower than the pre-injury sports activity level ( p = 0.027 ) . High-resolution MRIs documented the presence of abnormal findings in terms of morphology , signal intensity , and interface between the implant and the native meniscus . Implant extrusion and bone oedema at the treated compartment were also observed in most of the cases , even though no correlation was found between imaging findings and clinical outcome . Conclusions The present study reports satisfactory clinical outcomes at mid-term follow-up after polyurethane-based meniscal cell-free scaffold implantation . The treatment was effective both in cases of isolated partial meniscal lesions and in complex cases requiring the combination with other surgical procedures . On the other h and , a high rate of altered MRI aspects was documented . However , no correlation was found between the altered imaging parameters and the overall positive clinical findings , thus supporting the use of this procedure to treat painful partial meniscus loss . Level of evidence Case series , Level IV Purpose The purpose of our study was to compare clinical and radiological results of two groups of patients treated for medial compartment osteoarthritis of the knee with either conventional or computer-assisted open-wedge high tibial osteotomy ( HTO ) .  Goals of surgical treatment were a correction of the mechanical axis between 2 ° and 6 ° of valgus and a modification of posterior tibial slope between −2 ° and + 2 ° . Methods Twenty-four patients ( 27 knees ) affected by varus knee deformity and operated with HTO were prospect ively followed-up . They were r and omly divided in two groups , A ( 11 patients , conventional treatment ) and B ( 13 patients , navigated treatment ) . The American Knee Society Score and the Modified Cincinnati Rating System Question naire were used for clinical assessment . All patients were radiologically evaluated with a comparative lower limb weight-bearing digital radiograph , a st and ard digital anteroposterior , a latero-lateral radiograph of the knee , and a Rosenberg view . Results Patients were followed-up at a mean of 39 months . Clinical evaluation showed no statistical difference ( n.s . ) between the two groups . Radiological results showed an 86 % reproducibility in achieving a mechanical axis of 182 ° –186 ° in group B compared to a 23 % in group A ( p = 0.0392 ) ; furthermore , in group B , we achieved a modification of posterior tibial slope between −2 ° and + 2 ° in 100 % of patients , while in group A , this goal was achieved only in 24 % of cases ( p = 0.0021 ) . Conclusion High tibial osteotomy with navigator is more accurate and reproducible in the correction of the deformity compared to st and ard technique . Level of evidence Therapeutic study , Level II PURPOSE To present the results of a polyurethane meniscal scaffold implant in 10 patients with persistent pain after meniscectomy . METHODS Prospect i ve , descriptive study of ten patients who underwent arthroscopic implantation of a polyurethane meniscal scaffold .  Functional , MRI , and radiography assessment was performed pre-operatively and at 6-months , 1-year , and a final follow-up at a minimum of two years . Clinical evaluation included Lysholm score , KOOS and VAS . The  MRI  morphology and signal intensity of the implant were evaluated according to the criteria of Genovese et al. RESULTS Statistically significant differences were found between the mean Lysholm score before surgery ( 63.5 points ) , and that at 6 months ( 76.8 points ) ( p=.001 ) , one year ( 83.3 points ) ( p<.001 ) and final follow-up ( 84.4 points ) ( p<.001 ) . KOOS showed significant differences between before surgery ( 64.23 points ) , 6 months ( 73.66 points ) ( p=.001 ) , one year ( 81.39 points ) ( p<.001 ) and final follow-up ( 83.34 points ) ( p<.001 ) . The mean values for VAS were 5.7 points in the pre-operative evaluation , 3.6 points at 6 months-follow-up ( p<.001 ) , 1.9 points at one year ( p<.001 ) , and 1.9 points at final follow-up ( p<.001 ) . Radiology showed degenerative changes in one case . In MRI , the size of the implant and the intensity of the MRI signal gradually decreased , but it never changed to that of a normal meniscus . CONCLUSION A significant improvement was found in all the clinical parameters 24 months after the surgery , except in one patient who underwent furher surgery . The scaffold reduced its size and but never achieved an MRI image similar to that of a normal meniscus . The procedure proved to be safe and useful for the treatment of persistent pain after meniscectomy Background : Loss of meniscal tissue can be responsible for increased pain and decreased function . Hypothesis : At a minimum 10-year follow-up , patients receiving a medial collagen meniscus implant ( MCMI ) would show better clinical , radiological , and magnetic resonance imaging ( MRI ) outcomes than patients treated with partial medial meniscectomy ( PMM ) . Study Design : Cohort study ; Level of evidence 2 . Methods : Thirty-three nonconsecutive patients ( men ; mean age , 40 years ) with meniscal injuries were enrolled in the study to receive MCMI or to serve as a control patient treated with PMM . The choice of treatment was decided by the patient . All patients were clinical ly evaluated at time 0 and at 5 years and a minimum of 10 years after surgery ( mean follow-up , 133 months ) by Lysholm , visual analog scale ( VAS ) for pain , objective International Knee Documentation Committee ( IKDC ) knee form , and Tegner activity level scores . The SF-36 score was performed preoperatively and at final follow-up . Bilateral weightbearing radiographs were completed before the index surgery and at final follow-up . Minimum 10-year follow-up MRI images were compared with preoperative MRI images by means of the Yulish score . The Genovese score was also used to evalute MCMI MRI survivorship . Results : The MCMI group , compared with the PMM one , showed significantly lower VAS for pain ( 1.2 ± 0.9 vs 3.3 ± 1.8 ; P = .004 ) and higher objective IKDC ( 7A and 10B for MCMI , 4B and 12C for PMM ; P = .0001 ) , Teger index ( 75 ± 27.5 vs 50 ± 11.67 ; P = .026 ) , and SF-36 ( 53.9 ± 4.0 vs 44.1 ± 9.2 ; P = .026 for Physical Health Index ; 54.7 ± 3.8 vs 43.8 ± 6.5 ; P = .004 for Mental Health Index ) scores . Radiographic evaluation showed significantly less medial joint space narrowing in the MCMI group than in the PMM group ( 0.48 ± 0.63 mm vs 2.13 ± 0.79 mm ; P = .0003 ) . No significant differences between groups were reported regarding Lysholm ( P = .062 ) and Yulish ( P = .122 ) scores . Genovese score remained constant between 5 and 10 years after surgery ( P = .5 ) . The MRI evaluation of the MCMI patients revealed 11 cases of myxoid degeneration signal : 4 had a normal signal with reduced size , and 2 had no recognizable implant . Conclusion : Pain , activity level , and radiological outcomes are significantly improved with use of the MCMI at a minimum 10-year follow-up compared with PMM alone . R and omized controlled trials on a larger population are necessary to confirm MCMI benefits at long term BACKGROUND Segmental tissue loss in the lateral meniscus is associated with pain and increased risk of osteoarthritis even when indications have been carefully considered . HYPOTHESIS Repairing the defect using a novel biodegradable scaffold will reduce pain and restore the knee function . METHODS In this prospect i ve multicenter study , a total of 54 patients ( 37 males/17 females ; mean age : 28 years [ 16 - 50 ] ) were enrolled . All patients presented with postmeniscectomy syndrome and segmental lateral meniscus loss , and were treated with a polyurethane biodegradable scaffold ( Actifit ( ® ) , Orteq ) implanted arthroscopically . Clinical outcomes were assessed at 6 , 12 and 24 months using Visual Analogue Scale ( VAS ) , International Knee Documentation Committee Score ( IKDC ) and Knee Injury and Osteoarthritis Outcome Score ( KOOS ) . RESULTS VAS decreased from 5.5 at baseline to 3.6 at 6 months , 3.4 at 12 months and 2.9 at 24 months . IKDC improved from 47.0 at baseline to 60.2 , 67.0 and 67.0 at 6 , 12 and 24 months . All KOOS subscores improved between baseline and 24 months . DISCUSSION Clinical results of this study demonstrate clinical ly and statistically significant improvements of pain and function scores ( VAS , IKDC , and all KOOS subscales except sport ) , at the 6 months follow-up and on all clinical outcomes at the 2-year follow-up . The Actifit ( ® ) scaffold is safe and effective in treating lateral meniscus defects . LEVEL OF EVIDENCE IV continuous prospect i ve multicenter study The meniscus performs critical functions within the knee , and its loss frequently leads to osteoarthritis and irreversible joint damage . Because prosthetic replacement of the meniscus has proven ineffective , the authors used tissue engineering techniques to develop a resorbable collagen scaffold ( collagen meniscus implant ) that supports ingrowth of new tissue and eventual regeneration of the lost meniscus . Eight patients underwent arthroscopic placement the collagen meniscus implant to reconstruct and restore the irreparably damaged medial meniscus of one knee . Seven patients had one or more prior meniscectomies , and one patient had an acute meniscus injury . Patients were observed with frequent clinical , serologic , radiographic , and magnetic resonance imaging examinations for at least 24 months ( range , 24 - 32 months ) . All patients underwent relook arthroscopy and biopsy of the implant regenerated tissue at either 6 or 12 months after implantation . All patients improved clinical ly from preoperatively to 1 and 2 years postoperatively based on pain , Lysholm scores , Tegner activity scale , and self assessment . Relook arthroscopy revealed tissue regeneration in all patients with apparent preservation of the joint surfaces based on visual observations . Histologic analysis confirmed new fibrocartilage matrix formation . Radiographs confirmed no progression of degenerative joint disease . The collagen meniscus implant is implantable , biocompatible , resorbable , and supports new tissue regeneration as it is resorbed . This tissue seems to function similar to meniscus tissue by protecting the chondral surfaces Background : A novel , biodegradable , aliphatic polyurethane scaffold was design ed to fulfill an unmet clinical need in the treatment of patients with irreparable partial meniscal lesions . Hypothesis : Treatment of irreparable partial meniscal lesions with an acellular polyurethane scaffold supports new tissue ingrowth . Study Design : Case series ; Level of evidence , 4 . Methods : Fifty-two patients ( with 34 medial and 18 lateral lesions ) were recruited into a prospect i ve , single-arm , multicenter , proof-of-principle study and treated with the polyurethane scaffold . The scaffold was implanted after partial meniscectomy using st and ard surgeon-preferred techniques for suturing .  Tissue ingrowth was assessed at 3 months by dynamic contrast-enhanced magnetic resonance imaging ( DCE-MRI ) and at 12 months by gross examination during second-look arthroscopy , in the course of which a biopsy sample from the inner free edge of the scaffold meniscus was taken for qualitative histologic analysis . Results : Tissue ingrowth at 3 months was demonstrated on DCE-MRI in 35 of 43 ( 81.4 % ) patients . All but one 12-month second-look ( 43 of 44 [ 97.7 % ] ) showed integration of the scaffold with the native meniscus and all biopsy specimens ( 44 ) showed fully vital material , with no signs of cell death or necrosis . Three distinct layers were observed based on morphologic structure , vessel structure presence or absence , and extracellular matrix composition . Conclusion : The DCE-MRI demonstrated successful early tissue ingrowth into the scaffold . The biopsy findings demonstrated the biocompatibility of the scaffold and ingrowth of tissue with particular histologic characteristics suggestive of meniscus-like tissue . In conclusion , these data show for the first time consistent regeneration of tissue when using an acellular polyurethane scaffold to treat irreparable partial meniscus tissue lesions Background : A novel , biodegradable , polyurethane scaffold was design ed to fulfill an unmet clinical need in the treatment of patients with painful irreparable partial meniscal defects . Hypothesis : The use of an acellular polyurethane scaffold for new tissue generation in irreparable partial meniscal defects provides both pain relief and improved functionality . Study Design : Case series ; Level of evidence , 4 . Methods : Fifty-two patients with irreparable partial meniscal defects ( 34 medial and 18 lateral , 88 % with 1 - 3 previous surgeries on the index meniscus ) were implanted with a polyurethane scaffold in a prospect i ve , single-arm , multicenter , proof-of-principle study . Safety was assessed by the rate of scaffold-related serious adverse events ( SAEs ) and the International Cartilage Repair Society articular cartilage scoring system comparing magnetic resonance imaging ( MRI ) at 24 months to MRI at baseline ( 1 week ) . Kaplan-Meier time to treatment failure distributions were performed . Clinical outcomes were measured comparing visual analog scale , International Knee Documentation Committee , Knee Injury and Osteoarthritis Outcome Score ( KOOS ) , and Lysholm scores at 24 months from baseline ( entry into study ) . Results : Clinical ly and statistically significant improvements ( P < .0001 ) compared with baseline were reported in all clinical outcome scores ( baseline/24 months ) : visual analog scale ( 45.7/20.3 ) , International Knee Documentation Committee ( 45.4/70.1 ) , KOOS symptoms ( 64.6/78.3 ) , KOOS pain ( 57.5/78.6 ) , KOOS activities of daily living ( 68.8/84.2 ) , KOOS sports ( 30.5/59.0 ) , KOOS quality of life ( 33.9/56.6 ) , and Lysholm ( 60.1/80.7 ) , demonstrating improvements in both pain and function . The incidence of treatment failure was 9 ( 17.3 % ) patients , of which 3 patients ( 8.8 % ) had medial meniscal defects and 6 patients ( 33.3 % ) had lateral meniscal defects . There were 9 SAEs requiring reoperation . Stable or improved International Cartilage Repair Society cartilage grade s were observed in 92.5 % of patients between baseline and 24 months . Conclusion : At 2 years after implantation , safety and clinical outcome data from this study support the use of the polyurethane scaffold for the treatment of irreparable , painful , partial meniscal defects
Purpose The purpose of this systematic review is to evaluate the current literature in an effort to assess specific clinical outcomes following meniscal scaffold implantation using the two available scaffolds : Collagen Meniscal Implant ( CMI ) and the Actifit polyurethane meniscal scaffold .