human
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: CONTEXT Tendon disorders comprise 30 % to 50 % of all activity-related injuries ; chronic degenerative tendon disorders ( tendinopathy ) occur frequently and are difficult to treat . Tendon regeneration might be improved by injecting platelet-rich plasma ( PRP ) , an increasingly used treatment for releasing growth factors into the degenerative tendon . OBJECTIVE To examine whether a PRP injection would improve outcome in chronic midportion Achilles tendinopathy . DESIGN , SETTING , AND PATIENTS A stratified , block-r and omized , double-blind , placebo-controlled trial at a single center ( The Hague Medical Center , Leidschendam , The Netherl and s ) of 54 r and omized patients aged 18 to 70 years with chronic tendinopathy 2 to 7 cm above the Achilles tendon insertion . The trial was conducted between August 28 , 2008 , and January 29 , 2009 , with follow-up until July 16 , 2009 . INTERVENTION Eccentric exercises ( usual care ) with either a PRP injection ( PRP group ) or saline injection ( placebo group ) . R and omization was stratified by activity level . MAIN OUTCOME MEASURES The vali date d Victorian Institute of Sports Assessment -Achilles ( VISA-A ) question naire , which evaluated pain score and activity level , was completed at baseline and 6 , 12 , and 24 weeks . The VISA-A score ranged from 0 to 100 , with higher scores corresponding with less pain and increased activity . Treatment group effects were evaluated using general linear models on the basis of intention-to-treat . RESULTS After r and omization into the PRP group ( n = 27 ) or placebo group ( n = 27 ) , there was complete follow-up of all patients . The mean VISA-A score improved significantly after 24 weeks in the PRP group by 21.7 points ( 95 % confidence interval [ CI ] , 13.0 - 30.5 ) and in the placebo group by 20.5 points ( 95 % CI , 11.6 - 29.4 ) . The increase was not significantly different between both groups ( adjusted between-group difference from baseline to 24 weeks , -0.9 ; 95 % CI , -12.4 to 10.6 ) . This CI did not include the predefined relevant difference of 12 points in favor of PRP treatment . CONCLUSION Among patients with chronic Achilles tendinopathy who were treated with eccentric exercises , a PRP injection compared with a saline injection did not result in greater improvement in pain and activity . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00761423 Background Elbow epicondylar tendinosis is a common problem that usually resolves with nonoperative treatments . When these measures fail , however , patients are interested in an alternative to surgical intervention . Hypothesis Treatment of chronic severe elbow tendinosis with buffered platelet-rich plasma will reduce pain and increase function in patients considering surgery for their problem . Study Design Cohort study ; Level of evidence , 2 . Methods One hundred forty patients with elbow epicondylar pain were evaluated in this study . All these patients were initially given a st and ardized physical therapy protocol and a variety of other nonoperative treatments .  Twenty of these patients had significant persistent pain for a mean of 15 months ( mean , 82 of 100 ; range , 60 - 100 of 100 on a visual analog pain scale ) , despite these interventions . All patients were considering surgery . This cohort of patients who had failed nonoperative treatment was then given either a single percutaneous injection of platelet-rich plasma ( active group , n = 15 ) or bupivacaine ( control group , n = 5 ) . Results Eight weeks after the treatment , the platelet-rich plasma patients noted 60 % improvement in their visual analog pain scores versus 16 % improvement in control patients ( P = . 001 ) . Sixty percent ( 3 of 5 ) of the control subjects withdrew or sought other treatments after the 8-week period , preventing further direct analysis . Therefore , only the patients treated with platelet-rich plasma were available for continued evaluation . At 6 months , the patients treated with platelet-rich plasma noted 81 % improvement in their visual analog pain scores ( P = . 0001 ) . At final follow-up ( mean , 25.6 months ; range , 12 - 38 months ) , the platelet-rich plasma patients reported 93 % reduction in pain compared with before the treatment ( P < . 0001 ) . Conclusion Treatment of patients with chronic elbow tendinosis with buffered platelet-rich plasma reduced pain significantly in this pilot investigation . Further evaluation of this novel treatment is warranted . Finally , platelet-rich plasma should be considered before surgical intervention 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 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 Non-insertional Achilles tendinopathy commonly impedes the functioning of active persons . Treatment methods vary , as do their results . The aim of the study was to evaluate the effectiveness of non-insertional Achilles tendinopathy treatment with autologous platelet-rich plasma ( PRP ) . Autologous PRP was injected into the affected Achilles tendon of 14 prospect ively selected patients ( 15 Achilles tendons ) . Before PRP administration , all patients were evaluated using the American Orthopedic Foot and Ankle Society ( AOFAS ) scale for the hind foot , and the Victorian Institute of Sport Assessment - Achilles ( VISA-A ) scale . Ultrasonography ( US ) and Power-Doppler ultrasonography ( PDUS ) of the area was also performed . Identical physical and imaging evaluations were performed at 6 weeks , and at 3 , 6 , and 18 months after injection . During follow up , a significant improvement was observed in the clinical and imaging results . The AOFAS scale improved from a baseline median of 55 points to 96 points at 18 months ( p=0.000655 ) , while the VISA-A scale improved from a baseline of 24 to 96 ( p=0.000655 ) in the final evaluations . During the final evaluation , one subject experienced minor pain following prolonged daily activity , while another subject complained of pain following overloading activity . Local , accurate PRP administration improved symptoms of non-insertional Achilles tendinopathy 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 Background Platelet-rich fibrin matrices release a natural mixture of growth factors that play central roles in the complex processes of tendon healing . Hypothesis Application of autologous platelet-rich matrices during Achilles tendon surgery may promote healing and functional recovery . Study Design Case-control study and descriptive laboratory study ; Level of evidence , 3 . Methods Twelve athletes underwent open suture repair after complete Achilles tendon tear .  Open suture repair in conjunction with a preparation rich in growth factors ( PRGF ) was performed in 6 athletes and retrospectively compared with a matched group that followed conventional surgical procedure . The outcomes were evaluated on the basis of range of motion , functional recovery , and complications . Achilles tendons were examined by ultrasound at 50 ± 11 months in retrospective controls and 32 ± 10 months in the PRGF group . In the laboratory portion of the study , PRGF treatment was characterized by the number of platelets and concentration of insulin ( IGF-I ) , transformed ( TGF-β1 ) , platelet-derived ( PDGF-AB ) , vascular endothelial ( VEGF ) , hepatocyte ( HGF ) , and epidermal ( EGF ) growth factors in patients affected by musculoskeletal traumatic injuries . Results Athletes receiving PRGF recovered their range of motion earlier ( 7 ± 2 weeks vs 11 ± 3 weeks , P = .025 ) , showed no wound complication , and took less time to take up gentle running ( 11 ± 1 weeks vs 18 ± 3 weeks , P = .042 ) and to resume training activities ( 14 ± 0.8 weeks vs 21 ± 3 weeks , P = .004 ) . The cross-sectional area of the PRGF-treated tendons increased less ( t = 3.44 , P = .009 ) . TGF-β1 ( 74.99 ± 32.84 ng/mL ) , PDGF-AB ( 35.62 ± 14.57 ng/mL ) , VEGF ( 383.9 ± 374.9 pg/mL ) , EGF ( 481.5 ± 187.5 pg/mL ) , and HGF ( 593.87 ± 155.76 pg/mL ) significantly correlated with the number of platelets ( 677 ± 217 platelets/μL , P < .05 ) . Conclusion The operative management of tendons combined with the application of autologous PRGF may present new possibilities for enhanced healing and functional recovery . This needs to be evaluated in a r and omized clinical trial Background and purpose . Arthroscopic repair of rotator cuff tears can produce excellent results . The application of platelet rich plasma during arthro 
    Output:
    
agent
***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: CONTEXT Tendon disorders comprise 30 % to 50 % of all activity-related injuries ; chronic degenerative tendon disorders ( tendinopathy ) occur frequently and are difficult to treat . Tendon regeneration might be improved by injecting platelet-rich plasma ( PRP ) , an increasingly used treatment for releasing growth factors into the degenerative tendon . OBJECTIVE To examine whether a PRP injection would improve outcome in chronic midportion Achilles tendinopathy . DESIGN , SETTING , AND PATIENTS A stratified , block-r and omized , double-blind , placebo-controlled trial at a single center ( The Hague Medical Center , Leidschendam , The Netherl and s ) of 54 r and omized patients aged 18 to 70 years with chronic tendinopathy 2 to 7 cm above the Achilles tendon insertion . The trial was conducted between August 28 , 2008 , and January 29 , 2009 , with follow-up until July 16 , 2009 . INTERVENTION Eccentric exercises ( usual care ) with either a PRP injection ( PRP group ) or saline injection ( placebo group ) . R and omization was stratified by activity level . MAIN OUTCOME MEASURES The vali date d Victorian Institute of Sports Assessment -Achilles ( VISA-A ) question naire , which evaluated pain score and activity level , was completed at baseline and 6 , 12 , and 24 weeks . The VISA-A score ranged from 0 to 100 , with higher scores corresponding with less pain and increased activity . Treatment group effects were evaluated using general linear models on the basis of intention-to-treat . RESULTS After r and omization into the PRP group ( n = 27 ) or placebo group ( n = 27 ) , there was complete follow-up of all patients . The mean VISA-A score improved significantly after 24 weeks in the PRP group by 21.7 points ( 95 % confidence interval [ CI ] , 13.0 - 30.5 ) and in the placebo group by 20.5 points ( 95 % CI , 11.6 - 29.4 ) . The increase was not significantly different between both groups ( adjusted between-group difference from baseline to 24 weeks , -0.9 ; 95 % CI , -12.4 to 10.6 ) . This CI did not include the predefined relevant difference of 12 points in favor of PRP treatment . CONCLUSION Among patients with chronic Achilles tendinopathy who were treated with eccentric exercises , a PRP injection compared with a saline injection did not result in greater improvement in pain and activity . TRIAL REGISTRATION clinical trials.gov Identifier : NCT00761423 Background Elbow epicondylar tendinosis is a common problem that usually resolves with nonoperative treatments . When these measures fail , however , patients are interested in an alternative to surgical intervention . Hypothesis Treatment of chronic severe elbow tendinosis with buffered platelet-rich plasma will reduce pain and increase function in patients considering surgery for their problem . Study Design Cohort study ; Level of evidence , 2 . Methods One hundred forty patients with elbow epicondylar pain were evaluated in this study . All these patients were initially given a st and ardized physical therapy protocol and a variety of other nonoperative treatments .  Twenty of these patients had significant persistent pain for a mean of 15 months ( mean , 82 of 100 ; range , 60 - 100 of 100 on a visual analog pain scale ) , despite these interventions . All patients were considering surgery . This cohort of patients who had failed nonoperative treatment was then given either a single percutaneous injection of platelet-rich plasma ( active group , n = 15 ) or bupivacaine ( control group , n = 5 ) . Results Eight weeks after the treatment , the platelet-rich plasma patients noted 60 % improvement in their visual analog pain scores versus 16 % improvement in control patients ( P = . 001 ) . Sixty percent ( 3 of 5 ) of the control subjects withdrew or sought other treatments after the 8-week period , preventing further direct analysis . Therefore , only the patients treated with platelet-rich plasma were available for continued evaluation . At 6 months , the patients treated with platelet-rich plasma noted 81 % improvement in their visual analog pain scores ( P = . 0001 ) . At final follow-up ( mean , 25.6 months ; range , 12 - 38 months ) , the platelet-rich plasma patients reported 93 % reduction in pain compared with before the treatment ( P < . 0001 ) . Conclusion Treatment of patients with chronic elbow tendinosis with buffered platelet-rich plasma reduced pain significantly in this pilot investigation . Further evaluation of this novel treatment is warranted . Finally , platelet-rich plasma should be considered before surgical intervention 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 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 Non-insertional Achilles tendinopathy commonly impedes the functioning of active persons . Treatment methods vary , as do their results . The aim of the study was to evaluate the effectiveness of non-insertional Achilles tendinopathy treatment with autologous platelet-rich plasma ( PRP ) . Autologous PRP was injected into the affected Achilles tendon of 14 prospect ively selected patients ( 15 Achilles tendons ) . Before PRP administration , all patients were evaluated using the American Orthopedic Foot and Ankle Society ( AOFAS ) scale for the hind foot , and the Victorian Institute of Sport Assessment - Achilles ( VISA-A ) scale . Ultrasonography ( US ) and Power-Doppler ultrasonography ( PDUS ) of the area was also performed . Identical physical and imaging evaluations were performed at 6 weeks , and at 3 , 6 , and 18 months after injection . During follow up , a significant improvement was observed in the clinical and imaging results . The AOFAS scale improved from a baseline median of 55 points to 96 points at 18 months ( p=0.000655 ) , while the VISA-A scale improved from a baseline of 24 to 96 ( p=0.000655 ) in the final evaluations . During the final evaluation , one subject experienced minor pain following prolonged daily activity , while another subject complained of pain following overloading activity . Local , accurate PRP administration improved symptoms of non-insertional Achilles tendinopathy 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 Background Platelet-rich fibrin matrices release a natural mixture of growth factors that play central roles in the complex processes of tendon healing . Hypothesis Application of autologous platelet-rich matrices during Achilles tendon surgery may promote healing and functional recovery . Study Design Case-control study and descriptive laboratory study ; Level of evidence , 3 . Methods Twelve athletes underwent open suture repair after complete Achilles tendon tear .  Open suture repair in conjunction with a preparation rich in growth factors ( PRGF ) was performed in 6 athletes and retrospectively compared with a matched group that followed conventional surgical procedure . The outcomes were evaluated on the basis of range of motion , functional recovery , and complications . Achilles tendons were examined by ultrasound at 50 ± 11 months in retrospective controls and 32 ± 10 months in the PRGF group . In the laboratory portion of the study , PRGF treatment was characterized by the number of platelets and concentration of insulin ( IGF-I ) , transformed ( TGF-β1 ) , platelet-derived ( PDGF-AB ) , vascular endothelial ( VEGF ) , hepatocyte ( HGF ) , and epidermal ( EGF ) growth factors in patients affected by musculoskeletal traumatic injuries . Results Athletes receiving PRGF recovered their range of motion earlier ( 7 ± 2 weeks vs 11 ± 3 weeks , P = .025 ) , showed no wound complication , and took less time to take up gentle running ( 11 ± 1 weeks vs 18 ± 3 weeks , P = .042 ) and to resume training activities ( 14 ± 0.8 weeks vs 21 ± 3 weeks , P = .004 ) . The cross-sectional area of the PRGF-treated tendons increased less ( t = 3.44 , P = .009 ) . TGF-β1 ( 74.99 ± 32.84 ng/mL ) , PDGF-AB ( 35.62 ± 14.57 ng/mL ) , VEGF ( 383.9 ± 374.9 pg/mL ) , EGF ( 481.5 ± 187.5 pg/mL ) , and HGF ( 593.87 ± 155.76 pg/mL ) significantly correlated with the number of platelets ( 677 ± 217 platelets/μL , P < .05 ) . Conclusion The operative management of tendons combined with the application of autologous PRGF may present new possibilities for enhanced healing and functional recovery . This needs to be evaluated in a r and omized clinical trial Background and purpose . Arthroscopic repair of rotator cuff tears can produce excellent results . The application of platelet rich plasma during arthro 
    Output:
    