Comparison of the collagen meniscus implant with partial meniscectomy. A prospective randomized trial. Arthroscopic collagen meniscus implant results at 6 to 8 years follow up Prospective Long-Term Outcomes of the Medial Collagen Meniscus Implant Versus Partial Medial Meniscectomy Potential market for new meniscus repair strategies: evaluation of the MOON cohort. [Replacement of the meniscus with a collagen implant (CMI)]. Tissue Ingrowth After Implantation of a Novel, Biodegradable Polyurethane Scaffold for Treatment of Partial Meniscal Lesions
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 Meniscal substitution is a fundamental procedure to prevent osteoarthritis of the knee after massive meniscectomy . Stone , Steadman and Rodkey have developed a bioreadsorbable collagen matrix ( CMI ) which acts as a scaffold to restore the original medial meniscal . The objective of this study was to prospect ively evaluate the results of CMI implantation at a follow up from a minimum of 6 to a maximum of 8 years . Eight patients ( mean age 25 ) were evaluated at a final observation point from 6 to 8 years after CMI implantation . Inclusion criteria were an irreparable meniscal tear or a previous meniscectomy involving the medial meniscus . Follow up evaluation included Cincinnati Knee Rating Scale ( CKRS ) , IKDC , subjective evaluation and X-ray and MRI control . There were no complications related to the device . All patients were able to return to day activities without limitations 3 months after surgery . Both subjective CKRS score and objective IKDC score showed improvement in all cases except one patient with an ACL re-injury . In two cases scores were slightly worse from 2 years after surgery to the final observation point . The other five cases obtained maximum score at final follow-up . In four cases the absence of pain remained until the final observation point , while in four cases a low entity of pain was described at long term follow-up . MRI showed in five cases mixoid degeneration signal , two had normal signal with reduced size , while one patient had no recognizable implant . Six patients had preserved cartilage and articular space , with no changes respect to pre-op control . Arthroscopic second look evaluation has been performed in three cases , revealing in two cases the presence of the implant , although with a reduced size respect to the original one , while in one case the CMI was almost disappeared . Our small series of eight patients prospect ively followed from 6 to 8 years of follow-up has shown highly satisfactory results . Although the aspect of the implant was mostly abnormal , the implant may have helped reduce the deterioration of the knee joint at final observation time 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 This study aim ed to determine the incidence of meniscal tears and describe the tear morphology and selected treatment in patients undergoing anterior cruciate ligament ( ACL ) reconstruction .  We also will discuss the potential market for future tissue engineering aim ed at preserving meniscal function . A multicenter cohort of 1014 patients undergoing ACL reconstruction between January 2002 and December 2003 was evaluated . Data on patient demographics , presence of a meniscus tear at time of ACL reconstruction , tear morphology , and meniscal treatment were collected prospect ively . Meniscal tears were categorized into 3 potential tissue engineering treatment strategies : all-biologic repair , advanced repair , and scaffold replacement . Of the knees , 36 % had medial meniscal tears and 44 % had lateral meniscal tears . Longitudinal tears were the most common tear morphology . The most frequent treatment method was partial meniscectomy . Thirty percent of medial meniscal tears and 10 % of lateral meniscal tears are eligible for all-biologic repair ; 35 % of medial meniscal tears and 35 % of lateral meniscal tears are eligible for an advanced repair technique ; and 35 % of medial meniscal tears and 55 % of lateral meniscal tears are eligible for  scaffold replacement .  Although meniscal preservation is generally accepted in the treatment of meniscal tears , most tears in this cohort were not repairable , despite contemporary methods . The results of this cohort will hopefully stimulate and focus future research and development of new tissue engineering strategies for meniscus repair 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 degrees until week 4 , 0/0/90 degrees until week 6 . Continuous 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 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
PURPOSE The aim of this systematic review was to address tissue engineering and regenerative medicine ( TERM ) strategies applied to the meniscus , specifically ( 1 ) clinical applications , indications , results , and pitfalls and ( 2 ) the main trends in research assessed by evaluation of pre clinical ( in vivo ) studies .