Is there a role for adult non-cultivated bone marrow stem cells in ACL reconstruction? Reduction of tunnel enlargement with use of autologous ruptured tissue in anterior cruciate ligament reconstruction: a pilot clinical trial. Bone Morphogenetic Protein–7 (Osteogenic Protein–1) Promotes Tendon Graft Integration in Anterior Cruciate Ligament Reconstruction in Sheep Effects of Remnant Tissue Preservation on the Tendon Graft in Anterior Cruciate Ligament Reconstruction Acute anterior cruciate ligament reconstruction with an augmented remnant repair: a comparative macroscopic and biomechanical study in an animal model. Comparison of magnetic resonance imaging findings in anterior cruciate ligament grafts with and without autologous platelet-derived growth factors. Remnant Repair-enhanced Polyethylene Terepthalate Artificial Ligament Graft Ligamentization. Use of a Bioactive Scaffold to Stimulate Anterior Cruciate Ligament Healing Also Minimizes Posttraumatic Osteoarthritis After Surgery The impact of platelet-rich plasma on the prevention of tunnel widening in anterior cruciate ligament reconstruction using quadrupled autologous hamstring tendon: a randomised clinical trial. Incidence of Second ACL Injuries 2 Years After Primary ACL Reconstruction and Return to Sport Effects of platelet concentrate and a bone plug on the healing of hamstring tendons in a bone tunnel. Platelet-rich plasma: does it help reduce tunnel widening after ACL reconstruction? Weak link of tendon–bone healing and a control experiment to promote healing Anatomic ACL reconstruction: does the platelet-rich plasma accelerate tendon healing? The effectiveness of demineralized cortical bone matrix in a chronic rotator cuff tear model. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions Influence of hydroxyapatite-coated and growth factor-releasing interference screws on tendon-bone healing in an ovine model. Intraarticular application of autologous conditioned serum (ACS) reduces bone tunnel widening after ACL reconstructive surgery in a randomized controlled trial Effects of Demineralized Bone Matrix on Tendon-Bone Healing in an Intra-articular Rodent Model Has platelet-rich plasma any role in anterior cruciate ligament allograft healing? Enhancement of the osseointegration of a polyethylene terephthalate artificial ligament graft in a bone tunnel using 58S bioglass A Novel Silk Fiber–Based Scaffold for Regeneration of the Anterior Cruciate Ligament The effect of transforming growth factor-beta1 on intraosseous healing of flexor tendon autograft replacement of anterior cruciate ligament in dogs. Nanohydroxyapatite-based bone graft substitute in tunnel enlargement after ACL surgery: RMN study. Comparison between two different platelet-rich plasma preparations and control applied during anterior cruciate ligament reconstruction. Is there any evidence to support their use? Arthroscopic anterior cruciate ligament reconstruction with periosteum-enveloping hamstring tendon graft Shockwave therapy improves anterior cruciate ligament reconstruction. Effect of muscle preserved on tendon graft on intra-articular healing in anterior cruciate ligament reconstruction Magnetic resonance imaging evaluation of the integration and maturation of semitendinosus-gracilis graft in anterior cruciate ligament reconstruction using autologous platelet concentrate. Hamstrings anterior cruciate ligament reconstruction with and without platelet rich fibrin matrix Increased platelet concentration does not improve functional graft healing in bio-enhanced ACL reconstruction Magnetic Resonance Imaging Evaluation of Patellar Tendon Graft Remodelling after Anterior Cruciate Ligament Reconstruction with or without Platelet-Rich Plasma Effect of Calcium Phosphate–Hybridized Tendon Graft in Anterior Cruciate Ligament Reconstruction The long‐term clinical and radiological outcomes in patients who suffer recurrent injuries to the anterior cruciate ligament after reconstruction Biomechanical and Biological Findings Between Acute Anterior Cruciate Ligament Reconstruction With and Without an Augmented Remnant Repair: A Comparative in Vivo Animal Study.
Purpose To assess by magnetic resonance imaging ( MRI ) if adult non-cultivated bone marrow stem cells accelerate tendon-to-bone healing in the femoral tunnel , after hamstring anterior cruciate ligament ( ACL ) reconstruction . Methods Forty-three patients underwent ACL reconstruction and were prospect ively r and omized into two groups : 20 patients in the experimental group ( group A ) with adult non-cultivated bone marrow stem cells and 23 patients in the control group ( group B ) without adult non-cultivated bone marrow stem cells . All patients underwent MRI of the knee at three months after surgery to evaluate the signal-to-noise ratio of the interzone . Results There was no difference in the signal-to-noise ratio of the interzone on MRI between the experimental and the control group . Conclusions Adult non-cultivated bone marrow stem cells do not seem to accelerate graft-to-bone healing in ACL reconstruction . The clinical relevance of this finding is that adult non-cultivated bone marrow stem cells apparently have a limited role in ACL reconstruction . Level of evidence II PURPOSE To compare the tunnel enlargement of  double-bundle ( DB ) anterior cruciate ligament reconstruction ( ACLR )  with and without suturing of autologous ruptured tissue to hamstring graft in patients with subacute anterior cruciate ligament injury . METHODS Ten patients with subacute ( ≤3 months after injury ) anterior cruciate ligament rupture were r and omly allocated to undergo DB ACLR with suturing of the ruptured tissue to hamstring graft ( n = 5 ) or conventional DB ACLR ( n = 5 ) . When autologous ruptured tissue was used , remnant ruptured tissue was then harvested , divided into 4 pieces , placed between the loops at the distal and proximal portions of the graft , and secured with the suture . As the primary endpoint , tunnel volume assessment by  3-dimensional multi-detector row computed tomography ( MDCT ) was performed 1 year after ACLR . To assess the efficacy of these procedures , the Lysholm score , anterior tibial translation ( measured with a KT-1000 arthrometer [ MEDmetric , San Diego , CA ] ) , and rotational instability ( measured by the pivot-shift test ) were evaluated after 2 years . RESULTS Tunnel volume enlargement between 3 weeks and 1 year after ACLR as assessed by 3-dimensional MDCT was significantly less for ACLR using ruptured tissue than for conventional ACLR , especially at the femoral site ( P < .05 ) . However , the postoperative Lysholm score , anterior stability of the knee measured with the KT-1000 arthrometer , and rate of negative manual pivot-shift test results did not differ significantly between the 2 groups . There was no correlation to the clinical outcomes in terms of tunnel size . CONCLUSIONS The Lysholm score , anterior laxity measured with the KT-1000 arthrometer , and rotational instability according to the pivot-shift test did not differ significantly between ACLR using ruptured tissue and the conventional technique . However , ACLR using ruptured tissue produced less femoral tunnel enlargement as assessed by MDCT , warranting further long-term follow-up to eluci date its effectiveness . LEVEL OF EVIDENCE Level II , prospect i ve comparative study Background Bone morphogenetic proteins induce new bone both in patients with bone defects and at extraskeletal sites in animals . After anterior cruciate ligament rupture , tendon graft fixation into a bone tunnel is a widely used method for anterior cruciate ligament reconstruction . Hypothesis Bone morphogenetic protein–7 applied to the bone-tendon interface enables better integration of a free tendon graft into the surrounding bone . Study Design Controlled laboratory study . Methods The anterior cruciate ligament was reconstructed using a free tendon graft in the right rear knees of 30 one-year-old male sheep .  Recombinant human bone morphogenetic protein–7 ( 25 μg ) was applied r and omly to the bone-tendon interface in 15 animals , and a vehicle was applied in 15 control animals . At 3 weeks , 10 animals from each group were sacrificed , and the remaining sheep were sacrificed at 6 weeks after surgery . Subsequently , histologic analysis and mechanical testing were performed . In another group of 20 sheep , the same procedure was used and mechanical testing was performed after 3 weeks . Results More new bone was formed at the bone-tendon interface in the knees treated with bone morphogenetic protein–7 as compared histologically with similar areas in control animals , creating areas of dense trabecular network with significantly greater invasion of the tendon fibrous tissue into the bone marrow space . Mechanical testing showed greater strain resistance to force ( 368 N ) in the knees treated with bone morphogenetic protein–7 than in control specimens ( 214 N ) . There was no difference between mechanical testing of sample s from 3 and 6 weeks after surgery . Conclusion Bone morphogenetic protein–7 promotes complete tendon graft integration into the newly formed surrounding trabecular bone in the reconstruction of the anterior cruciate ligament . Clinical Relevance Bone morphogenetic protein–7 in tendon graft integration might be successfully used in reconstructive surgery of ligaments Background : There is controversy regarding the efficacy of remnant tissue preservation on graft healing in anterior cruciate ligament ( ACL ) reconstruction . Hypothesis : The preserved remnant tissue will ( 1 ) adhere to the graft surface and undergo a remodeling process , ( 2 ) accelerate graft revascularization , ( 3 ) increase the number of graft mechanoreceptors by 4 weeks , and ( 4 ) improve anteroposterior knee laxity and structural properties of the graft by 12 weeks . Study Design : Controlled laboratory study . Methods : Forty-two sheep were r and omly divided into 2 groups of 21 animals . In group I , the ACL was completely removed . In group II , the ACL was transected at the midsubstance but not debrided . ACL reconstruction was performed using a semitendinosus tendon autograft in both groups . Histological changes of the grafted tendon and the remnant tissue were evaluated at 4 and 12 weeks after surgery . Biomechanically , anterior translation and knee joint stiffness under an anterior drawer force and the structural properties of the femur-graft-tibia complex were evaluated . Results : The preserved remnant tissue was histologically distinct from the graft at 4 weeks , while the tissue partially adhered to the graft surface at 12 weeks . The ACL remnant tissue significantly accelerated revascularization in the grafted tendon at 4 weeks and significantly increased the number of mechanoreceptors at 4 and 12 weeks . In addition , remnant preservation significantly improved anterior translation ( 9.3 ± 2.1 mm and 5.4 ± 1.7 mm at 60 ° of knee flexion in groups I and II , respectively ) and knee joint stiffness at 12 weeks . However , there were no significant differences in the structural properties between the 2 groups at 4 and 12 weeks after surgery . Conclusion : Preservation of the ACL remnant tissue in ACL reconstruction enhanced cell proliferation , revascularization , and regeneration of proprioceptive organs in the reconstructed ACL and reduced anterior translation . However , remnant preservation did not improve the structural properties of the graft . Clinical Relevance : These results imply that preservation of the ACL remnant tissue may improve graft healing after ACL reconstruction PURPOSE Our purpose was ( 1 ) to compare the structural integrity and healing capacity of the acutely repaired anterior cruciate ligament ( ACL ) remnants and ( 2 ) to determine whether the short-term postoperative biomechanical results of the acute remnant-repairing anterior cruciate ligament reconstruction ( ACLR ) were superior to the conventional ACLR . METHODS An acute complete ACL femoral detachment model was created in 50 rabbits . The rabbits were immediately r and omly allocated into the remnant-repairing ACLR group ( group 1 , n = 25 ) and the conventional ACLR group ( group 2 , n = 25 ) . Each animal in both groups was subjected to unilateral ACLR with semitendinosus tendon autografts . During ACLR , the ACL remnants were acutely repaired with the femoral-tensioning technique in group 1 , whereas the ACL remnants were debrided in group 2 . The outcomes of the remnant were macroscopically evaluated in group 1 . The remnant 's structural integrity and remnant-to-graft healing capacity were divided into 3 categories ( grade A , good ; grade B , fair ; or grade C , poor ) according to 2 distinct criteria . Biomechanical tests including the anterior tibial translation test at 30 ° and 90 ° of knee flexion and tensile tests were compared between groups . All the macroscopic evaluations and biomechanical tests were performed postoperatively at week 12 . RESULTS The macroscopic evaluations of the ACL remnants in group 1 ( n = 25 ) showed that the remnants ' structural integrity was grade A ( well-maintained continuity with an adequate amount of tissue and tension on probing ) in 10 specimens ( 40 % ) , grade B ( fairly maintained continuity with thin and slack fibers detected ) in 5 ( 20 % ) , and grade C ( resorption with no remnant left in situ ) in 10 ( 40 % ) . The remnant-to-graft healing capacities among the specimens with surviving remnants ( grade s A and B for structural integrity , n = 15 ) were all classified as grade C ( an obvious remnant-to-graft interval through the entire length of the graft ) . For the biomechanical tests , there were no significant differences between the groups ( 25 in each group ) with respect to the anterior tibial translation test at 30 ° ( P = .15 ) and 90 ° ( P = .91 ) of knee flexion and stiffness ( P = .66 ) , ultimate failure load ( P = .11 ) , and elongation at failure ( P = .92 ) . CONCLUSIONS In our rabbit model of ACL femoral detachment , the acutely repaired ACL remnants showed a high resorption rate , low healing capacity , and poor biomechanical properties . The acute remnant-repairing ACLR had no evident superiority over the conventional ACLR  in rabbits . CLINICAL RELEVANCE The findings did not support the contention that the remnant-repairing ACLR , even performed in the acute setting , could produce better postoperative knee joint stability outcomes than the conventional ACLR PURPOSE To determine whether the use of platelet-rich plasma gel ( PRPG ) affects magnetic resonance imaging ( MRI ) findings in the anterior cruciate ligament ( ACL ) graft during the first year after reconstruction . METHODS A prospect i ve single-blinded study of 50 ACL reconstructions in 50 patients was performed . In group A ( study group ) PRPG was added to the graft with a st and ardized technique , and in group B ( control group ) no PRPG was added . An  MRI study  was performed postoperatively between 3 and 9 months in group A and between 3 and 12 months in group B. The imaging analysis was performed in a blind protocol by the same radiologist . RESULTS The mean heterogeneity score value at the time of MRI , assigned by the radiologist , was 1.14 in group A and 3.25 in group B. Both groups were comparable in terms of sex and age ( P < .05 ) . The mean time to obtain a completely homogeneous intra-articular segment in group A ( PRPG added ) was 177 days after surgery , and it was 369 days in group B. Using the quadratic predictive model , these findings show that group A ( PRPG added ) needed only 48 % of the time group B required to achieve the same MRI image ( P < .001 ) . CONCLUSIONS ACL reconstruction with the use of PRPG achieves complete homogeneous grafts assessed by MRI , in 179 days compared with 369 days for ACL reconstruction without PRPG . This represents a time shortening of 48 % with respect to ACL reconstruction without PRPG The aim of this study was to investigate whether augmented remnant repair could enhance polyethylene terepthalate ( PET ) artificial ligament graft ligamentization . 12 female goats underwent ACL reconstruction with PET artificial ligament graft in the right knees . Right knees in 6 goats were reconstructed with augmented remnant repair ( Remnant group ) , whereas the other 6 goats had no augmented remnant repair  comprised the Control group . 3 goats in each group were r and omly sacrificed at 6 months and 12 months respectively after surgery . The intra-articular parts of the reconstructed grafts were harvested for histological evaluation . Well-vascularized tissue ingrowth within the artificial ligament was observed in the remnant group at 12 months postoperatively . Collagen-I content of graft was significantly higher in the Remnant group than in the Control group at each time point ( p<0.05 ) . The relative expression of collagen-III positive area of the remnant-preserved group was significantly higher than that of the Control group at 12 months ( p=0.005 ) . The vascular endothelial growth factor (VEGF)-positive or CD31-positive area in the graft appeared higher in the Remnant group compared with the Control group at 6 months . Remnant repair enhanced the revascularization and remodeling of the PET artificial ligament in ACL reconstruction Background : Although  anterior cruciate ligament ( ACL ) reconstruction  is the treatment gold st and ard for ACL injury , it does not reduce the risk of posttraumatic osteoarthritis . Therefore , new treatments that minimize this postoperative complication are of interest . Bioenhanced ACL repair , in which a bioactive scaffold is used to stimulate healing of an ACL transection , has shown considerable promise in short-term studies . The long-term results of this technique and the effects of the bioenhancement on the articular cartilage have not been previously evaluated in a large animal model . Hypotheses : ( 1 ) The structural ( tensile ) properties of the porcine ACL at 6 and 12 months after injury are similar when treated with bioenhanced ACL repair , bioenhanced ACL reconstruction , or conventional ACL reconstruction , and all treatments yield results superior to untreated ACL transection . ( 2 ) After 1 year , macroscopic cartilage damage following bioenhanced ACL repair is similar to that in bioenhanced ACL reconstruction and less than in conventional ACL reconstruction and untreated ACL transection . Study Design : Controlled laboratory study . Methods : A total of 64 Yucatan mini-pigs underwent ACL transection and r and omization to 4 experimental groups : no treatment , conventional ACL reconstruction , bioenhanced ACL reconstruction using a bioactive scaffold , and bioenhanced ACL repair using a bioactive scaffold . The biomechanical properties of the ligament or graft were examined and macroscopic assessment s of the cartilage surfaces were performed after 6 and 12 months of healing . Results : The structural properties ( ie , linear stiffness , yield , and maximum loads ) of the ligament after bioenhanced ACL repair were not significantly different from those in bioenhanced ACL reconstruction or conventional ACL reconstruction but were significantly greater than those in untreated ACL transection after 12 months of healing . Macroscopic cartilage damage after bioenhanced ACL repair was significantly less than that in untreated ACL transection and bioenhanced ACL reconstruction , and there was a strong trend ( P = .068 ) for less macroscopic cartilage damage than in conventional ACL reconstruction in the porcine model at 12 months . Conclusion : Bioenhanced ACL repair produces a ligament that is biomechanically similar to an ACL graft and provides chondroprotection to the joint after ACL surgery . Clinical Relevance : Bioenhanced ACL repair may provide a new , less invasive treatment option that reduces cartilage damage following joint injury The use of platelet-rich plasma ( PRP ) as an adjuvant to tissue repair is gaining favour in orthopaedic surgery . Tunnel widening after anterior cruciate ligament ( ACL ) reconstruction is a recognised phenomenon that could compromise revision surgery . The purpose of this study was to determine whether PRP might prevent tunnel widening in ACL reconstruction . Patients undergoing ACL reconstruction using a hamstring graft were r and omly allocated either to have PRP introduced into the tunnels peri-operatively or not . CT scanning of the knees was carried out on the day after surgery and at three months post-operatively and the width of the tunnels was measured . Patients were also evaluated clinical ly at three months , when laxity was also measured . Each group comprised 25 patients , and at three months post-operatively all were pain-free with stable knees , a negative Lachman test and a good range of movement . Arthrometric results had improved significantly in both groups ( p < 0.001 ) . Despite slightly less tunnel widening in the PRP group , there was no significant difference between the groups at the femoral opening or the mid-tunnel ( p = 0.370 and p = 0.363 , respectively ) nor at the tibial opening or mid-tunnel ( p = 0.333 and p = 0.177 , respectively).We conclude that PRP has no significant effect in preventing tunnel widening after ACL reconstruction Background : The incidence of second anterior cruciate ligament ( ACL ) injuries in the first 12 months after ACL reconstruction ( ACLR )  and return to sport ( RTS ) in a young , active population has been reported to be 15 times greater than that in a previously uninjured cohort . There are no reported estimates of whether this high relative rate of injury continues beyond the first year after RTS and ACLR . Hypothesis : The incidence rate of a subsequent ACL injury in the 2 years after ACLR and RTS would be less than the incidence rate reported within the first 12 months after RTS but greater than the ACL injury incidence rate in an uninjured cohort of young athletes . Study Design : Cohort study ; Level of evidence , 2 . Methods : Seventy-eight patients ( mean age , 17.1 ± 3.1 years ) who underwent ACLR and were ready to return to a pivoting/cutting sport and 47 controls ( mean age , 17.2 ± 2.6 years ) who also participated in pivoting/cutting sports were prospect ively enrolled . Each participant was followed for injury and athlete exposure ( AE ) data for a 24-month period after RTS . Twenty-three ACLR and 4 control participants suffered an ACL injury during this time . Incidence rate ratios ( IRRs ) were calculated to compare the rates ( per 1000 AEs ) of ACL injury in athletes in the ACLR and control groups . For the ACLR group , similar comparisons were conducted for side of injury by sex . Results : The overall incidence rate of a second ACL injury within 24 months after ACLR and RTS ( 1.39/1000 AEs ) was nearly 6 times greater ( IRR , 5.71 ; 95 % CI , 2.0 - 22.7 ; P = .0003 ) than that in healthy control participants ( 0.24/1000 AEs ) . The rate of injury within 24 months of RTS for female athletes in the ACLR group was almost 5 times greater ( IRR , 4.51 ; 95 % CI , 1.5 - 18.2 ; P = .0004 ) than that for female controls . Although only a trend was observed , female patients within the ACLR group were twice as likely ( IRR , 2.43 ; 95 % CI , 0.8 - 8.6 ) to suffer a contralateral injury ( 1.13/1000 AEs ) than an ipsilateral injury ( 0.47/1000 AEs ) . Overall , 29.5 % of athletes suffered a second ACL injury within 24 months of RTS , with 20.5 % sustaining a contralateral injury and 9.0 % incurring a retear injury of the ipsilateral graft . There was a trend toward a higher proportion of female participants ( 23.7 % ) who suffered a contralateral injury compared with male participants ( 10.5 % ) ( P = .18 ) . Conversely , for ipsilateral injuries , the incidence proportion between female ( 8.5 % ) and male ( 10.5 % ) participants was similar . Conclusion : These data support the hypothesis that in the 24 months after ACLR and RTS , patients are at a greater risk to suffer a subsequent ACL injury compared with young athletes without a history of ACL injuries . In addition , the contralateral limb of female patients appears at greatest risk PURPOSE The purpose of this study was to determine if the use of platelet concentrate ( PC ) and bone plug ( BP ) does accelerate the healing process in anterior cruciate ligament ( ACL ) reconstruction . METHODS One hundred and eight patients requiring ACL reconstruction were prospect ively r and omized into 4 groups :  control  ( 27 patients ) , PC ( 26 patients ) , BP ( 28 patients ) , and a combination of PC and BP ( 27 patients ) . Magnetic resonance imaging ( MRI ) studies were carried out at both 3 and 6 months postsurgery . Maturation of the graft was evaluated at the femoral tunnel using MRI maturation criteria defined by a low-intensity signal , absence of osteoligamentous interface , and no widening of the femoral tunnel . RESULTS Three months after surgery , no differences were found among the groups regarding MRI maturation criteria . Six months postsurgery , 78 % of the patients in the control group had a low-intensity signal , while in the PC group the low-intensity signal was present in 100 % of the patients ( P = .036 ) . No statistical differences were observed regarding the osteoligamentous interface between the various groups . Finally , tunnel widening was seen in 11 % of the patients of the BP group versus 41 % of the patients in the control group ( P = .047 ) , but no statistical difference was seen with the other groups . CONCLUSIONS The use of PC had an enhancing effect on the graft maturation process evaluated only by MRI signal intensity , without showing any significant effect in the osteoligamentous interface or tunnel widening evolution . The use of a BP effectively prevented tunnel widening . The BP and PC combination did not show a synergic effect as compared to PC or BP individually . LEVEL OF EVIDENCE Level II , lesser quality r and omized controlled trial Purpose The purpose of this study was to evaluate the efficacy of platelet-rich plasma ( PRP ) in reducing femoral and tibial tunnel enlargement in patients operated on for anterior cruciate ligament reconstruction with hamstrings . Methods Forty male patients , in which both femoral and tibial 9-mm tunnels were performed because of the graft size , were enrolled in this prospect i ve study . They were r and omly assigned to group A ( 20 patients , PRP group ) and group B ( 20 patients , control group ) . All patients were followed up at a median of 14.7 months ( range 10–16 months ) , with a physical examination , the Tegner , Lysholm and objective IKDC scoring scales , and with the KT-1000 arthrometer . Moreover , they underwent a  CT evaluation in order to assess the amount of tunnel enlargement . Results Femoral tunnel diameter increased from 9.0 ± 0.1 mm to 9.8 ± 0.3 mm in group A ( p = 0.032 ) and from 9.0 ± 0.1 mm to 9.4 ± 0.5 mm in group B ( p = 0.043 ) . Tibial tunnel diameter increased from 9.0 ± 0.2 mm to 10.9 ± 0.2 mm in group A ( p = 0.029 ) and from 9.1 ± 0.1 mm to 10.1 ± 0.4 mm in group B ( p = 0.028 ) . Physical examination as well as the evaluation scales used showed no differences between the two groups . Conclusions The use of PRP does not seem to be effective in preventing tunnel enlargement . Level of evidence Therapeutic study , Level II Objective This study aims to observe the mechanical weak point and histological features of tendon – bone interface after anterior cruciate ligament reconstructive surgery  and to explore the tendon – bone healing effects of the platelet-rich gel ( PRG ) + deproteinized bone ( DPB ) compound . Methods A total of 48 New Zeal and white rabbits were r and omly divided into normal group , model ( without embedding ) , experimental ( embedded with the PRG + DPB compound ) , and control ( embedded with DPB ) groups . The rabbits were executed at 2 , 4 , 8 , and 12 weeks after the operation . Then , micro-computed tomography scan and uniaxial tensile test were conducted . The fractured specimens were subjected to histological observation . Results At 4 , 8 , and 12 weeks after the operation , the bone density of the tendon – bone bound section of the experimental group was higher than that of the other groups ( P < 0.05 ) . At 4 and 8 weeks , the maximum tensile load of the experimental group was obviously higher than that of the control and model groups ( P < 0.05 ) . Histological observation indicated that the tendon – bone interface in the experimental group had more cartilage and bone tissue growing toward the internal tendon , but the fracture layer mainly occurred in the non-ankylosed part . Conclusion The mechanical weak point of the early tendon – bone interface was in the immature fibrous tissue . The PRG + DPB compound can effectively trigger tendon – bone healing by promoting the maturation and ossification of the tendon – bone tissue . This compound improved the tensile strength of the healing interface and reduced bone tunnel enlargement Recently , the use of hamstring tendons in anterior cruciate ligament repair has been increasing . However , tendon-to-bone healing occurs slowly , which can be a problem to an early return to sport activities . The use of growth factors from platelets seems to improve tissue healing . We enrolled 40 patients in a prospect i ve study that were su bmi tted to an anatomic reconstruction of the anterior cruciate ligament . Patients were sequentially enrolled into four groups : group A without platelet-rich plasma ( PRP ) ; group B with PRP in femoral tunnels at the end of surgery ; group C with PRP in femoral tunnels at the end of surgery and intra-articular at 2- and 4 weeks after surgery ; group D with PRP activated with thrombin in the femoral tunnels . All patients underwent magnetic resonance imaging of the knee 3 months after surgery to evaluate the signal intensity of the fibrous interzone ( FIZ ) in the femoral tunnels . We did not find any difference among the groups when comparing the signal intensity of the FIZ on magnetic resonance imaging BACKGROUND The purpose of this study was to assess the effect of demineralized bone matrix ( DBM ) on rotator cuff tendon-bone healing . The hypothesis was that compared with a commercially available dermal matrix scaffold , DBM would result in a higher bone mineral density and regenerate a morphologically superior enthesis in a rat model of chronic rotator cuff degeneration . METHODS Eighteen female Wistar rats underwent unilateral detachment of the supraspinatus tendon . Three weeks later , tendon repair was carried out in animals r and omized into 3 groups : group 1 animals were repaired with DBM ( n = 6 ) ; group 2 received augmentation with the dermal scaffold ( n = 6 ) ; and group 3 ( controls ) underwent nonaugmented tendon-bone repair ( n = 6 ) . Specimens were retrieved at 6 weeks postoperatively for histologic analysis and evaluation of bone mineral density . RESULTS No failures of tendon-bone healing were noted throughout the study . All groups demonstrated closure of the tendon-bone gap with a fibrocartilaginous interface . Dermal collagen specimens exhibited a disorganized structure with significantly more abnormal collagen fiber arrangement and cellularity than in the DBM-based repairs . Nonaugmented repairs exhibited a significantly higher bone mineral density than in DBM and the dermal collagen specimens and were not significantly different from control limbs that were not operated on . CONCLUSION The application of DBM to a rat model of chronic rotator cuff degeneration did not improve the composition of the healing enthesis compared with nonaugmented controls and a commercially available scaffold . However , perhaps the most important finding of this study was that the control group demonstrated a similar outcome to augmented repairs Non-r and omised studies of the effects of interventions are critical to many areas of healthcare evaluation , but their results may be biased . It is therefore important to underst and and appraise their strengths and weaknesses . We developed ROBINS-I ( “ Risk Of Bias In Non-r and omised Studies - of Interventions ” ) , a new tool for evaluating risk of bias in estimates of the comparative effectiveness ( harm or benefit ) of interventions from studies that did not use r and omisation  to allocate units ( individuals or clusters of individuals ) to comparison groups . The tool will be particularly useful to those undertaking systematic review s that include non-r and omised studies PURPOSE Our purpose was to determine whether a bioresorbable interference screw coated with a hydroxyapatite-based mineral layer design ed to release an engineered peptide growth factor ( linkBMP-2 [ where " BMP-2 " indicates bone morphogenetic protein 2 ] ) improved tendon-bone healing compared with a screw without coating . METHODS Tagged linkBMP-2 peptides were used to quantify binding efficiency and release kinetics on 9 mineral-coated BIORCI screws ( Smith & Nephew , And over , MA ) . Fourteen mature female sheep were used in this study . In each of the 14 sheep , each stifle was r and omized to either receive a linkBMP-2-coated or uncoated interference screw ( n = 14 per treatment ) . The sheep were euthanized at 6 weeks after surgery . Eight sheep were subjected to biomechanical testing for peak load at failure and stiffness , and six sheep were used for histologic analysis according to a semiquantitative scoring scale . RESULTS The linkBMP-2 molecule bound efficiently to the surface of mineral-coated interference screws . Over 80 % of the initially bound linkBMP-2 was released during a 6-week time frame in vitro . Peak load at failure in the linkBMP-2-coated interference screw group ( mean + /- SD , 449.3 + /- 84.7 N ) was not significantly different from that in the uncoated group ( 421.0 + /- 61.8 N ) ( P = .22 ) . Stiffness in the linkBMP-2-coated interference screw group ( 157.3 + /- 39.6 N/mm ) was not significantly different from that in the uncoated group ( 140.6 + /- 20.3 N/mm ) ( P = .12 ) . Histologic analysis showed that the tendons in the linkBMP-2-coated interference screw group had higher scores ( better ) than the uncoated group . In the linkBMP-2-coated interference screw group , mesenchymal cells were present at the interface between screw and tendon , whereas these cells were not present in the uncoated group . CONCLUSIONS We found that linkBMP-2 can be bound onto a mineral-coated BIORCI interference screw surface and subsequently released from the screw surface in a sustained manner . The histologic result of this study showed that the linkBMP-2-coated interference screw significantly improved the histologic scores of early tendon-bone healing in this sheep model . CLINICAL RELEVANCE This linkBMP-2 coating material may improve early tendon/ligament fixation Purpose Pro-inflammatory cytokines play a pivotal role in osteoarthritis , as well as in bone tunnel widening after ACL reconstructive surgery . A new treatment option is to administer autologous conditioned serum ( ACS ) containing endogenous anti-inflammatory cytokines including IL-1Ra and growth factors ( IGF-1 , PDGF , and TGF-β1 , among others ) in the liquid blood phase . The purpose of this trial was to establish whether the postoperative outcome could be affected by intraarticular application of ACS . Methods In a prospect i ve , r and omized , double-blinded , placebo-controlled trial with two parallel groups , 62 patients were treated .  Bone tunnel width was measured by CT scans , while clinical efficacy was assessed by patient-administered outcome instruments ( WOMAC , IKDC 2000 ) up to 1 year following the ACL reconstruction in patients receiving either ACS ( Group A ) or placebo ( Group B ) . We compared the levels and dynamics of IL-1β concentrations in the synovial liquid and examined the correlation between the levels of IL-1β at three different postoperative points . Results Bone tunnel enlargement was significantly less ( 6 months : 8 % , 12 months : 13 % ) in Group A than in Group B ( 6 months : 31 % , 12 months : 38 % ) . Clinical outcomes ( WOMAC , IKDC 2000 ) were consistently better in patients treated with ACS at all data points and for all outcome parameters , and there were statistically significant differences in the WOMAC stiffness subscale after 1 year . The decrease in IL-1β synovial fluid concentration was more pronounced in the ACS group , and values were lower , to a statistically significant degree , in the ACS group at day 10 . Conclusion The intraarticular administration/injection of ACS results in decreased bone tunnel widening after ACL reconstructive surgery . Level of evidence Therapeutic study , R and omized controlled trial ( significant differences and narrow confidence intervals ) , Level Background : Techniques to improve and accelerate tendon-bone healing could be advantageous in anterior cruciate ligament ( ACL ) reconstruction . Effects of demineralized bone matrix ( DBM ) on intra-articular tendon-bone healing have not been examined . Hypothesis : Demineralized bone matrix has the potential to convey osteoinductive growth proteins to the site of healing at the tendon-bone interface . We hypothesized that the presence of DBM will result in more bone formation and hasten tendon-bone healing . Study Design : Controlled laboratory study . Methods : Fifty-six female athymic rnu/rnu ( nude ) rats were used . Rats were r and omly allocated into 2 groups ( control or treatment ) . The control group underwent an ACL reconstruction , while the treatment group had human DBM implanted in the tendon graft and bone tunnel before reconstruction . Rats were sacrificed at 2 ( n = 8) , 4 ( n = 24 ) , and 6 ( n = 24 ) weeks for histological , and immunohistochemical ( t = 2 , 4 , and 6 weeks ) , and biomechanical testing and micro – computed tomography ( t = 4 and 6 weeks ) end points . Results : Our findings suggest that in the presence of  DBM  , tendon-bone healing is augmented by increased woven bone formation and enhanced bone remodeling as indicated by histology and micro – computed tomography . This ultimately result ed in a statistically significant increase in peak load to failure of the tendon-bone interface at 4 weeks ( DBM group : 5.96 ± 1.36 N ; control group : 2.86 ± 0.7 N ) and 6 weeks ( DBM group : 9.13 ± 0.97 N ; control group : 5.81 ± 1.1 N ) . Conclusion : Demineralized bone matrix at the tendon-bone interface promotes healing between the tendon and bone in a rodent ACL model . Clinical Relevance : Introduction of osteoinductive DBM at the tendon-bone interface during ACL reconstructive surgery may improve short-term outcomes PURPOSE The aim of this study was to evaluate and compare the clinical and inflammatory parameters with the addition of platelet-derived growth factor ( PDGF ) in primary anterior cruciate ligament ( ACL ) reconstruction with bone-patellar tendon-bone allograft .  METHODS We prospect ively r and omized 100 patients undergoing arthroscopic patellar tendon allograft ACL reconstruction  to a group in whom platelet-enriched gel was used ( n = 50 ) and a non-gel group ( n = 50 ) . The platelet concentration was 837 x 10(3)/mm(3 ) , and the gel was introduced inside the graft and the tibial tunnel . Demographic data were comparable between groups . The mean follow-up was 24 months for both groups and included a history , clinical evaluation with the International Knee Documentation Committee score , radiographs , and magnetic resonance imaging . RESULTS There were no differences in the number of associated injuries . The results did not show any statistically significant differences between the groups for inflammatory parameters ( perimeters of the knee and C-reactive protein level ) , magnetic resonance imaging appearance of the graft , and clinical evaluation scores ( visual analog scale , International Knee Documentation Committee , and KT-1000 arthrometer [ MEDmetric , San Diego , CA ] ) . CONCLUSIONS At this time , the therapeutic role of PDGF in ACL reconstruction remains unclear . The use of PDGF , on the graft and inside the tibial tunnel , in patients treated with bone-patellar tendon-bone allografts has no discernable clinical or biomechanical effect at 2 years ' follow-up . More clinical studies will be needed to show the efficacy and use of these factors in daily practice in ACL reconstruction . LEVEL OF EVIDENCE Level I , prospect i ve , r and omized , double-blind study Purpose The aim of the study was to investigate whether a bioactive glass ( BG ) coating on the polyethylene terephthalate ( PET ) artificial ligament could enhance graft osseointegration by promoting bone regeneration at the interface between PET graft and bone tunnel . Methods Thirty New Zeal and white rabbits underwent artificial ligament graft transplantation in proximal tibial tunnels bilaterally . One limb was implanted with a 58S BG-coated PET graft , and the contralateral limb was implanted with a non-BG-coated PET graft as a control .  The rabbits were r and omly sacrificed at three , six and 12 weeks after surgery for biomechanical and histological examinations . Results The maximum load to failures of the BG-coated experimental group were significantly higher than those of the control group at 12 weeks ( p = 0.0051 ) . Histologically , at 12 weeks , the BG-coated PET graft induced great new bone formation between graft and host bone , and the average graft-bone interface width of the BG group became significantly lower than that of the control group . Furthermore , the BG coating on the ligament graft surface also stimulated greater expression of bone morphogenetic protein 2 ( BMP-2 ) and vascular endothelial growth factor ( VEGF ) around the graft in vivo compared to the control group at three weeks ( p < 0.05 ) . Conclusions This study has shown that a BG coating on the PET artificial ligament surface has a positive effect in the induction of artificial ligament osseointegration within the bone tunnel Background : Because of ongoing problems with anterior cruciate ligament ( ACL ) reconstruction , new approaches in the treatment of ACL injuries , particularly strategies based on tissue engineering , have gained increasing research interest . To allow for ACL regeneration , a structured scaffold that provides a mechanical basis , has cells from different sources , and comprises mechanical as well as biological factors is needed . Biological material s , biodegradable polymers , and composite material s are being used and tested as scaffolds . The optimal scaffold for ACL regeneration should be biocompatible and biodegradable to allow tissue ingrowth but also needs to have the right mechanical properties to provide immediate mechanical stability . Hypotheses : The study hypotheses were that ( 1 ) a novel degradable silk fiber – based scaffold with mechanical properties similar to the native ACL will be able to initiate ligament regeneration after ACL resection and reconstruction under in vivo conditions and ( 2 ) additional cell seeding of the scaffold with autologous stromal vascular fraction – containing adipose-derived stem cells will increase regenerative activity . Study Design : Controlled laboratory study . Methods : A total of 33 mountain sheep underwent ACL resection and r and omization to 2 experimental groups : ( 1 )  ACL reconstruction with a scaffold alone and ( 2 )  ACL reconstruction with a cell-seeded scaffold .  Histological evaluation of the intra-articular portion of the reconstructed/regenerated ligament was performed after 6 and 12 months . Results : After 6 months , connective tissue surrounded the silk scaffold with ingrowth in some areas . The cell-seeded scaffolds had a significant lower silk content compared with the unseeded scaffolds and demonstrated a higher content of newly formed tissue . After 12 months , the density of the silk fibers decreased significantly , and the ingrowth of newly formed tissue increased in both groups . No differences between the 2 groups regarding silk fiber degradation and regenerated tissue were detected at 12 months . Conclusion : The novel silk fiber – based scaffold was able to stimulate ACL regeneration under in vivo conditions . Additional cell seeding led to increased tissue regeneration and decreased silk fiber content at 6 months , whereas these differences were not present at 12 months . Clinical Relevance : ACL regeneration using a silk fiber – based scaffold with and without additional cell seeding may provide a new treatment option after joint injuries PURPOSE To clarify the effect of transforming growth factor (TGF)-beta1 on intraosseous healing of the flexor tendon autograft in anterior cruciate ligament ( ACL ) replacement . TYPE OF STUDY R and omized trial in animals . METHODS Twenty-one adult beagle dogs were divided into 3 groups of 7 animals each . The ACL was replaced with a flexor tendon autograft in the left knee . The distal end of each graft was placed in the tibial bone tunnel . In group I , no treatment was applied in the bone tunnel . In group II , 0.1 mL of fibrin sealant was applied in the tendon-bone gap . In group III , 2 ng of TGF-beta1 mixed with 0.1 mL fibrin sealant was applied in the gap . Each animal was euthanized 3 weeks after surgery . RESULTS In pullout testing , the ultimate load of the graft-tibia complex of group III ( 188.2 + /- 51.4 N ) was significantly greater than that of groups I ( 86.7 + /- 36.5 N ) and II ( 99.0 + /- 18.7 N ) ( P = .005 ) . There were no significant differences between groups I and II . Histologically , the perpendicular collagen fibers connecting the tendon to the bone were narrowly seen in groups I and II , whereas the fibers were richly generated in group III . CONCLUSIONS In ACL replacement using flexor tendon autograft , exogenous administration of TGF-beta1 significantly increased the bonding strength of the graft to the tunnel wall at 3 weeks , although the long-term effects are unknown . CLINICAL RELEVANCE Intraosseous healing of the flexor tendon autograft in ACL reconstruction may be enhanced by a use of some growth factors involving TGF-beta1 in the future BACKGROUND AND AIM A successful anterior cruciate ligament reconstruction ( ACL ) requires solid healing of the tendon graft in the bone tunnel . New biological strategies have already been proposed with the aim of improving ACL graft healing and therefore allowing a faster rehabilitative program . The aim of this prospect i ve study was to clinical ly and radiologically evaluate the efficacy of nanohydroxyapatite bone-base grafts in facilitating bone-tendon incorporation after ACL reconstruction with hamstrings ( HS ) . As far as we know , this is the first study that has tried to asses the efficacy of such a type of bone substitute on human beings . MATERIAL S AND METHODS 40 male patients with chronic ACL rupture who underwent surgical reconstruction with 4-str and semitendinosus and gracilis tendon autograft via a single-bundle technique .  Patients were r and omly assigned to enter group A ( 20 patients , nanohydroxyapatite group ) or group B ( 20 patients , control group ) . Preoperative and postoperative clinical evaluation was always performed , in a blinded way , assessing the Lachman and Pivot-shift tests and range of motion ( ROM ) of the affected knee . The Lysholm knee score , Tegner activity level , subjective and objective International Knee Documentation Committee ( IKDC ) forms , and 30 lb KT-1000 arthrometer evaluations . Patients underwent a magnetic resonance imaging ( MRI ) exam at 30 , 90 and 180 days after surgery by the same musculoskeletal radiologist in a blinded way . RESULTS As for the clinical evaluation , Lysholm , Tegner , IKDC scales , and KT-1000 arthrometer results did not show any significant difference between the two groups . Radiological data show a tendency toward better results in regard to the graft strength signal , the graftbone interface , and bone edema remodeling process , these parameters show significant differences between the two groups only at the short or mid-term follow-ups , while they are never significant at the mid-to long-term follow-up . CONCLUSIONS In conclusion the use of nanohydroxyapatite bone substitute does not provide significant clinical improvements in terms of better knee stability or patient satisfaction INTRODUCTION To compare the clinical , analytical and graft maturation effects of two different platelet-rich plasma ( PRP ) preparations applied during anterior cruciate ligament ( ACL ) reconstruction . MATERIAL S AND METHODS A total of 150 patients with ACL disruption were included in the study . Arthroscopic ACL reconstruction with patellar tendon allograft was conducted on all knees using the same protocol . One hundred patients were prospect ively r and omised to either a group to receive double-spinning platelet-enriched gel ( PRP ) with leukocytes ( n=50 ) or to a non-gel group ( n=50 ) . Finally , we included 50 patients treated with a platelet-rich preparation from a single-spinning procedure ( PRGF Endoret ( ® ) Technology ) without leukocytes . Inflammatory parameters , including C-reactive protein ( CRP ) and knee perimeters ( PER ) , were measured 24 hours and 10 days after surgery . Postoperative pain score ( visual analogue score [ VAS ] ) was recorded the day after surgery . Follow-up visits occurred postoperatively at 3 , 6 , and 12 months . The International Knee Documentation Committee scale ( IKDC ) was included to compare functional state , and MRI was conducted 6 months after surgery . RESULTS The PRGF group showed a statistically significant improvement in swelling and inflammatory parameters compared with the other two groups at 24 hours after surgery ( p<0.05 ) . The results did not show any significant differences between groups for MRI and clinical scores . CONCLUSIONS PRGF used in ACL allograft reconstruction was associated with reduced swelling ; however , the intensity and uniformity of the graft on MRI were similar in the three groups , and there was no clinical or pain improvement compared with the control group . LEVEL OF EVIDENCE II Tendon – bone incorporation of a tendon graft within the bone tunnel is of priority concern when using for anterior cruciate ligament ( ACL ) reconstruction . Superior healing process and stronger healing strength can be achieved when periosteum is sutured on the tendon inserted into a bone tunnel . We applied this idea to ACL reconstruction for enhancing tendon graft – bone tunnel healing . This is a prospect i ve clinical outcome study with this surgical technique at minimal 2 years follow-up . Periosteum-enveloping hamstring tendon graft has been used in 68 patients . Data from 62 patients who had been followed up completely were analyzed . All patients suffered from a grade 3 or higher grade of Lachman and anterior drawer test with a positive pivot-shift test . Clinical assessment s included the Lysholm knee scores , International Knee Documentation Committee ( IKDC ) scores , KT-1000 instrumented testing , thigh muscle assessment , and radiographic evaluation . The median Lysholm knee score was 59 ( 40–70 ) and 94 ( 60–100 ) points ( P<0.01 ) before and after surgery . After reconstruction , 81 % of patients were able to return to moderate or strenuous activity . Four ( 6 % ) patients were found to exhibit grade 2 or more ligament laxity . Complete range of motion could be achieved in 86 % of patients . Three patients ( 5 % ) had positive pivot shift . Finally , 92 % of patients were assessed as normal or nearly normal rating by IKDC guideline . Bone tunnels enlargement of more than 1 mm was identified in 5 % of femoral tunnels and 6 % of tibial tunnels . The study shows that a satisfactory result can be achieved with the periosteum-enveloping hamstring tendon graft in ACL reconstruction . Periosteum can be easily harvested at the proximal tibia from a routine incision for hamstring tendon harvesting . Besides the potential for improving tendon – bone healing , enveloped periosteum may help to seal the intra-articular tunnel opening in the early postoperative period , and thus avoid synovial fluid reflux into the tunnel . Bone tunnel enlargement could be reduced BACKGROUND Shockwave was shown to enhance the healing of anterior cruciate ligament ( ACL ) reconstruction in rabbits . This study evaluated the effect of extracorporeal shockwave therapy ( ESWT ) on ACL reconstruction in human subjects . We hypothesized that ESWT may improve human ACL reconstruction . METHODS Fifty-three patients were r and omized into two groups with 26 patients in ESWT group and 27 patients in control group . The ESWT group underwent single-bundle hamstring autograft ACL reconstruction and received ESWT immediately after surgery . The control group underwent ACL surgery without ESWT . Both groups received the same rehabilitation postoperatively . The evaluations included Lysholm score , IKDC score and KT-1000 , radiograph , bone mineral density , and magnetic resonance imaging . RESULTS ESWT group showed significantly better Lysholm score than control group at 1 and 2 y postoperatively ( P < 0.001 and 0.001 , respectively ) . No significant difference was noted in IKDC score between the two groups ( P = 0.080 and 0.076 , respectively ) . The KT-1000 values were significantly better in ESWT group than control group at 2 y postoperatively ( P = 0.027 ) . The tibia tunnel on X-ray was significantly smaller in ESWT group compared with control group at 2 y ( P = 0.018 ) . The bone mineral density values showed no discernable difference between the two groups at 6 mo and 2 y ( P = 0.522 and 0.984 , respectively ) . On magnetic resonance imaging , ESWT group showed significant decrease in tibia tunnel enlargement at 6 mo and 2 y compared with the control group ( P = 0.024 and < 0.001 , respectively ) . CONCLUSIONS ESWT significantly improves the subjective Lysholm score and decreases the middle 1/3 tibia tunnel enlargement after single hamstring autograft ACL reconstruction Purpose The aim of this study was to determine the impact on intra-articular healing of muscle tissue retained on tendon grafts used for anterior cruciate ligament ( ACL ) reconstruction . Methods In an animal study on 40 New Zeal and rabbits , a semi-tendon/semi-muscle graft ( SSG ) and a total tendon graft ( TTG ) were individually harvested from the Achilles tendons in each animal . After transecting the ACLs in both knees of each rabbit , SSG and TTG were r and omly used on bilateral sides of the knee for ACL reconstruction . After 2 , 4 , and 8 weeks , functional scoring , gross observations , and histological evaluations of the repaired knees were performed ( each time point ; n = 10 ) . Biomechanical testing was conducted on remaining animals at 8 weeks ( n = 10 ) . Results At 2 , 4 , and 8 weeks after surgery , there were no statistically significant differences in functional scores between the SSG group and TTG group ( n.s . ) . As healing progressed , skeletal muscle on the SSG was gradually absorbed with a corresponding decrease in graft diameter , compared to TTG , at each time point ( P < 0.001 ) . However , healing and incorporation of the intra-articular graft in the SSG were more apparent than those in the TTG , based on histology . The vascularity and cellularity in the center of the sample were significantly greater in the SSG group than the TTG group at all the time points ( P < 0.01 ) . At 8 weeks , the SSG group ’s ultimate failure load , yield load , and elongation at failure were significantly less than for the TTG group ( P < 0.01 ) . There were no significant differences in stiffness between the two groups with biomechanical testing ( n.s . ) . Conclusion Results of this study indicate that muscle left on tendon grafts promotes intra-articular healing and remodeling of the graft in a rabbit model . However , excessive amounts of retained skeletal muscle weaken tendon graft ’s strength for ACL reconstruction . Preserving small amounts of muscle on tendon grafts is feasible for improving the biological success of ACL reconstruction in humans PURPOSE To evaluate integration and maturation of semitendinosus-gracilis ( STG ) grafts in anterior cruciate ligament ( ACL ) reconstruction with magnetic resonance imaging ( MRI ) in patients who underwent ACL reconstruction with STG with and without autologous platelet concentrate ( APC ) .  METHODS A r and omized single-blinded evaluator prospect i ve study was performed in 2 consecutive series of patients who underwent reconstruction over a 14-month period : 30 with APC use ( group A ) and 20 as control subjects ( group B ) . At 6 months , an  MRI evaluation was performed , with observation of the graft 's maturation and presence or absence of synovial fluid at the tunnel-graft interface . To facilitate interpretation , a scoring scale was design ed to evaluate graft integration and maturation . RESULTS Regarding the presence of synovial fluid at the bone-graft interface , the test was negative in 86.84 % of patients in group A and 94.74 % in group B. A disorganized autograft signal pattern was found in 2.63 % in group A and 5.26 % in group B. Signal intensity was considered hypointense in 63.16 % in group A and 42.11 % in group B , isointense in 34.21 % in group A and 52.63 % in group B , and hyperintense in 0 % in both groups . The final mean score was 4.45 points in group A and 4.2 points in group B ( P ≥ .05 ) . Poor integration was found in 2.63 % in group A and 5.26 % in group B ( P = .214 ) . Good integration was found in 97.37 % in group A and 94.74 % in group B ( P = .784 ) . CONCLUSIONS In our consecutive series of patients who underwent ACL reconstruction with STG grafts , 1 group with intraoperative APC use versus a control group , followed up by MRI at 6 months after reconstruction , we did not find any statistically significant benefit in the APC group in terms of integration assessment and graft maturation ( ligamentization ) . LEVEL OF EVIDENCE Level III , case-control study Purpose Anterior cruciate ligament ( ACL ) rupture is the most common complete ligamentous injury in the knee . Many studies explored ACL graft integration and maturation , but only a few assessed the application of platelet rich fibrin matrix ( PRFM ) as augmentation for ACL reconstruction . The main aim of this study was to test the PRFM augmentation in terms of graft – bone integration and knee stability . The secondary aim was to investigate patient-reported functional status . Methods Prospect i ve evaluation has been done in two consecutive series of patients who underwent ACL reconstruction with semitendinosus and gracilis ( STG ) grafts : 14 patients were operated with PRFM augmentation and 14 patients without PRFM augmentation .  Objective clinical evaluation ( Rolimeter ) and MRI evaluation were performed at 1 year from surgery . Subjective evaluation ( IKDC ) was performed pre-operatively and at 6 months , 1 and 2 years from surgery . Results A statistically significant difference was not detected between the two groups in terms of MRI and objective clinical evaluation , although PRFM-augmented patients showed a statistically significant higher clinical improvement . Conclusions The procedure described for PRFM augmentation in ACL STG reconstruction does not improve radiologic graft integration and knee stability after 1 year and should not be used by clinicians to this purpose . However , it may result in a short-term improvement of patient-reported knee function , and future research should focus on further developing PRP treatment to optimize ACL clinical outcome .Level of evidence III Purpose The use of an extracellular matrix scaffold ( ECM ) combined with platelets to enhance healing of an anterior cruciate ligament ( ACL ) graft ( “ bio-enhanced ACL reconstruction ” ) has shown promise in animal models . However , the effects of platelet concentration on graft healing remain unknown . The objectives of this study were to determine whether increasing the platelet concentration in the ECM scaffold would ( 1 ) improve the graft biomechanical properties and ( 2 ) decrease cartilage damage after surgery . Methods Fifty-five adolescent minipigs were r and omized to five treatment groups : untreated ACL transection ( n = 10 ) , conventional ACL reconstruction ( n = 15 ) and bio-enhanced ACL reconstruction using 1 × ( n = 10 ) , 3 × ( n = 10 ) or 5 × ( n = 10 ) platelet-rich plasma .  The graft biomechanical properties , anteroposterior ( AP ) knee laxity , graft histology and macroscopic cartilage integrity were measured at 15 weeks . Results The mean linear stiffness of the bio-enhanced ACL reconstruction procedure using the 1 × preparation was significantly greater than traditional reconstruction , while the 3 × and 5 × preparations were not . The failure loads of all the ACL-reconstructed groups were equivalent but significantly greater than untreated ACL transection . There were no significant differences in the Ligament Maturity Index or AP laxity between reconstructed knees . Macroscopic cartilage damage was relatively minor , though significantly less when the ECM-platelet composite was used . Conclusions Only the 1 × platelet concentration improved healing over traditional ACL reconstruction . Increasing the platelet concentration from 1 × to 5 × in the ECM scaffold did not further improve the graft mechanical properties . The use of an ECM-platelet composite decreased the amount of cartilage damage seen after ACL surgery Purpose . To evaluate the stages of patellar tendon graft remodelling using magnetic resonance imaging ( MRI ) after anterior cruciate ligament ( ACL ) reconstruction with or without platelet-rich plasma ( PRP ) injection . Methods . 98 patients aged 18 to 65 years with complete rupture of the ACL were r and omised to undergo reconstruction with the autologous patellar tendon grafts with or without PRP injection . For the PRP group , 8 ml of PRP was obtained in the surgery room and was percutaneously injected into the suprapatellar joint after portal suture . MRI was obtained at months 4 , 6 , and 12 . Remodelling stages of the grafts were classified as hypointense , mildly hyperintense , moderately hyperintense , severely hyperintense , and diffusely hyperintense by a radiologist blinded to treatment allocation . Results . More patients in the  PRP group than controls attained higher stages of remodelling at month 4 ( p=0.003 ) , month 6 ( p=0.0001 ) , and month 12 ( p=0.354 ) . Conclusion . PRP enabled faster remodelling of patellar tendon grafts Background : The authors developed a novel technique to improve tendon-bone healing by hybridizing calcium phosphate ( CaP ) with a tendon graft using an alternating soaking process . Hypothesis : Anterior cruciate ligament ( ACL ) reconstruction using the CaP-hybridized tendon graft would have a better clinical outcome and reduce the percentage of bone tunnel enlargement compared with a conventional method because of the enhanced anchoring between the tendon graft and the bone . Study Design : R and omized controlled trial ; Level of evidence , 1 . Methods : Patients ( N = 64 ) with unilateral ACL rupture underwent arthroscopically assisted single-bundle ACL reconstruction using a 4-str and semitendinosus tendon or 4-str and semitendinosus and gracilis tendons with EndoButton femoral fixation and screw washer tibial fixation . These patients were equally r and omized to undergo the CaP ( n = 32 ) or conventional ( n = 32 ) method using a transtibial tunnel approach according to the closed envelope method . In the CaP group , the tendon graft was hybridized with the CaP at both ends of the graft . One surgeon performed all reconstructions without knowing which graft was prepared . Patients ’ background s regarding age at surgery , gender , period before surgery , and associated meniscal injuries were similar in the 2 groups . All patients followed the same postoperative protocol . At 1 and 2 years after surgery , they were evaluated with the manual knee laxity test , KT-1000 arthrometry , International Knee Documentation Committee ( IKDC ) examination form , Tegner scale , and Lysholm scale . Also , 1 year postoperatively , bone tunnel enlargement was analyzed using computed tomography , intensity of the tendon graft by magnetic resonance imaging ( MRI ) , and tendon graft appearance by arthroscopic examination . All the examinations were performed blindly . Results : All patients underwent a minimum 2-year follow-up . KT-1000 arthrometry data indicated statistically significant decreased average anterior tibial translation in the CaP group compared with the conventional method group : 1.0 ± 2.0 mm versus 1.9 ± 1.6 mm ( P < .05 ) , respectively , at 1 year ; 1.6 ± 2.1 mm versus 2.6 ± 2.4 mm ( P < .05 ) , respectively , at 2 years . The Lysholm score was higher in the CaP group than in the conventional method group at 2 years ( 96.9 ± 4.3 vs 91.7 ± 13.3 , P < .05 ) . The CaP-hybridized tendon graft reduced the percentage of bone tunnel enlargement of the anteroposterior diameter at the main joint aperture site 1 year postoperatively ( femoral side : 15.5 % ± 13.4 % vs 22.1 % ± 16.4 % , P < .05 ; tibial side : 19.3 % ± 17.1 % vs 26.1 % ± 13.7 % , P < .05 ) . The results of the pivot-shift test , IKDC grade , and Tegner score ; the intensity of the tendon graft ( MRI ) ; and arthroscopic appearance were not significantly different at both follow-up periods in the 2 groups . Conclusion : The CaP-hybridized tendon graft  improved anterior knee stability and Lysholm scores at the 2-year follow-up and improved anterior knee stability and reduced the percentage of bone tunnel enlargement in both tunnels at the 1-year follow-up compared with the conventional method for single-bundle ACL reconstruction . However , longer follow-up is needed to investigate the appearance of any increased instability Aims The aim of this study was to investigate the long‐term clinical and radiological outcome of patients who suffer recurrent injuries to the anterior cruciate ligament ( ACL ) after reconstruction and require revision surgery .  Patients and Methods From a consecutive series of 200 patients who underwent primary reconstruction following rupture of the ACL , we identified 36 who sustained a further rupture , 29 of whom underwent revision surgery .  Patients were review ed prospect ively at one , two , seven , 15 and about 20 years after their original surgery . Primary outcome measures were the number of further ruptures , the posterior tibial slope ( PTS ) , and functional and radiological outcomes . These were compared with a gender and age matched cohort of patients who underwent primary ACL reconstruction only .  Results At a mean follow‐up of 18.3 years ( 14.3 to 20.2 ) , 29 patients had undergone revision surgery and within this revision group 11 had sustained more than three ruptures of the ACL ( 3 to 6 ) . The mean age at the time of revision reconstruction  was 26.4 years ( 14 to 54 ) . The mean PTS was significantly higher in those patients who suffered a further injury to the ACL ( 11 ° ) compared with the control group ( 9 ° ) ( p < 0.001 ) . The mean PTS in those patients who sustained more than three ruptures was 12 ° . Conclusion Patients who suffer recurrent injuries to the ACL after reconstruction have poorer functional and radiological outcomes than those who suffer a single injury . The causes of further injury are likely to be multifactorial but an increased PTS appears to have a significant association with recurrent ACL injuries PURPOSE To investigate whether remnant-preserving anterior cruciate ligament reconstruction ( ACLR ) for acute complete anterior cruciate ligament ( ACL ) tears can improve the biomechanical strength , revascularization status , and proprioceptive recovery potential of the grafted tendons compared with conventional ACLR . METHODS An acute complete ACL femoral detachment model was created in 60 rabbits . The animals were r and omly allocated into the remnant-repairing ACLR group ( group 1 , n = 30 ) or the  conventional ACLR group ( group 2 , n = 30 ) . The ACL remnants were either acutely repaired with a femoral tensioning technique in group 1 or completely debrided in group 2 . For group 1 , remnant structural integrity was evaluated macroscopically and divided into grade A ( bridging femur and tibia ) and grade B ( not bridging femur and tibia ) . Then , the remnant-to-graft healing capacity was assessed histologically . For intergroup comparisons , the biomechanical strength of the grafted tendons was evaluated by tensile tests and the revascularization status ( vascular endothelial growth factor ) and proprioceptive recovery potential ( neurofilament ) of the grafted tendons were evaluated by immunofluorescent staining . All assessment s were performed postoperatively at week 24 . RESULTS In group 1 , 60 % of remnants ( 18 of 30 ) showed grade A and 40 % ( 12 of 30 ) showed grade B structural integrity . An obvious remnant-to-graft interval could be detected through the whole length of the graft . Tensile tests showed that the ultimate failure loads of the grafted tendons were similar between the groups ( P = .365 ) . In addition , there were no significant differences in the number of vascular endothelial growth factor-positive vessels and neurofilament-positive mechanoreceptors at either the femoral ( P = .887 and P = .578 , respectively ) , midsubstance ( P = .063 and P = .546 , respectively ) , or tibial ( P = .193 and P = .978 , respectively ) level within the grafted tendons between the groups . CONCLUSIONS The acute remnant-repairing ACLR in our rabbit femoral ACL detachment model showed no biomechanical and biological advantages compared with conventional ACLR . The acutely repaired ACL remnants presented a high proportion of poor structural integrity and low remnant-to-graft healing capacity . CLINICAL RELEVANCE During our clinical practice , conventional ACLR may still not be replaced by remnant-repairing ACLR for the treatment of acute complete ACL tears
Aims The success of anterior cruciate ligament reconstruction ( ACLR ) depends on osseointegration at the graft‐tunnel interface and intra‐articular ligamentization .
Our aim was to conduct a systematic review of clinical and pre clinical studies that evaluated biological augmentation of graft healing in ACLR .