***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: HYPOTHESIS Local application of autologous platelet rich plasma ( PRP ) improves tendon healing in patients undergoing arthroscopic rotator cuff repair . STUDY DESIGN Prospect i ve , r and omized , controlled , double blind study ; considering an alpha level of 5 % , a power of 80 % , 22 patients for group are needed . MATERIAL S AND METHODS Fifty-three patients who underwent shoulder arthroscopy for the repair of a complete rotator cuff tear were r and omly divided into 2 groups , using a block r and omization procedure . A treatment group ( N = 26 ) consisted of those who received an intraoperative application of PRP in combination with an autologous thrombin component . A control group ( N = 27 ) consisted of those who did not receive that treatment . Patients were evaluated with vali date d outcome scores . A magnetic resonance image ( MRI ) was performed in all cases at more than 1 year post-op . All patients had the same accelerated rehabilitation protocol . RESULTS The 2 groups were homogeneous . The pain score in the treatment group was lower than the control group at 3 , 7 , 14 , and 30 days after surgery ( P < .05 ) . On the Simple Shoulder Test ( SST ) , University of California ( UCLA ) , and Constant scores , strength in external rotation , as measured by a dynamometer , were significantly higher in the treatment group than the control group at 3 months after surgery ( strength in external rotation [ SER ] : 3 ± 1.6 vs 2.1 ± 1.3 kg ; SST : 8.9 ± 2.2 vs 7.1 ± 2.7 ; UCLA : 26.9 ± 3 vs 24.2 ± 4.9 ; Constant : 65 ± 9 vs 57.8 ± 11 ; P < .05 ) . There was no difference between the 2 groups after 6 , 12 , and 24 months . The follow-up MRI showed no significant difference in the healing rate of the rotator cuff tear . In the subgroup of grade 1 and 2 tears , with less retraction , SER in the PRP group was significant higher at 3 , 6 , 12 , and 24 months postoperative ( P < .05 ) . CONCLUSION The results of our study showed autologous PRP  reduced pain in the first postoperative months . The long-term results of subgroups of grade 1 and 2 tears suggest that PRP positively affected cuff rotator healing AIM The value of MRI for pre-operative evaluation of the rotator cuff is proven . In spite of its clinical relevance , there have been only few studies on MR imaging of patients who have already been operated . Thus , the question rises to what extent the post-operative MRI can contribute to the evaluation of the integrity of the rotator cuff . METHOD At least 10 months after successful open repair of the supraspinatus tendon , mostly combined with Neer 's anterior acromioplasty , an MR scan was performed on 33 shoulders . Only patients satisfied with the outcome of surgery and showing a Constant score of 65 to 100 points were included . RESULTS More than half the patients had positive direct diagnostic criteria for a full- or partial-thickness tear of the supraspinatus tendon , in the form of signal intensity or morphological alterations . In addition , the indirect diagnostic criteria described by Zlatkin , such as the absence of the subacromial-subdeltoid fat or the appearance of subacromial-subdeltoid fluid , were often positive . Atrophy of the supraspinatus muscle , as a further indirect diagnostic criterion of a rupture , was also frequently noted . CONCLUSION Taking the excellent clinical outcome of our patients into consideration , this study shows that caution should be taken in evaluating postoperative MR images . There is a high risk of over-interpreting MR findings Periosteal augmentation of tendons in the course of refixation to bone has been shown to be a suitable method for early primarily stable osteofibroblastic integration . The aim of this study was to evaluate the clinical and radiological results of open rotator cuff reconstruction using an autologous periosteal flap augmentation technique . The research was performed as a prospect i ve cohort study . Twenty-three prospect i ve patients ( average age 59.7 years ) with degenerative rotator cuff tears were operated on with an open technique and a subtendinous periosteal flap augmentation using bioabsorbable suture anchors and a modified Mason – Allen technique . Clinical evaluation consisted of the Constant-Score and the Simple Shoulder test . Radiological evaluation included st and ard radiographs and  magnetic resonance imaging ( MRI ) . Twenty patients were evaluated at a mean follow-up of 14.4 months . The average Constant Score increased significantly from 51.7 to 80.9 points ( p<0.05 ) with 12 excellent , seven good and one satisfactory result . The Simple Shoulder test showed a significant increase of an average of 4.8–10.7 questions answered with yes ( p<0.05 ) . Four patients ( 20 % ) demonstrated a retear of the tendon on postoperative MRI . Ectopic ossifications in the supraspinatus tendon were found in four patients ( 20 % ) but these had no impact on the final clinical results . Open rotator cuff repair augmented with an autologous periosteal flap shows high patient satisfaction level with low rerupture rates . Mid- and long-term results remain to be seen . The potential benefits compared with conventional open or arthroscopic rotator cuff surgery must be examined in prospect i ve r and omized studies BACKGROUND Controversy exists regarding the optimal technique for arthroscopic rotator cuff repair . The purpose of this multicenter , r and omized , double-blind controlled study was to compare the functional outcomes and healing rates after use of single-row and double-row suture techniques for repair of the rotator cuff . METHODS Ninety patients undergoing arthroscopic rotator cuff repair  were r and omized to receive either a single-row or a double-row repair . The primary objective was to compare the Western Ontario rotator cuff index ( WORC ) score at twenty-four months . Secondary objectives included comparison of the constant and american shoulder and elbow surgeons ( ASES ) scores and strength between groups . Anatomical outcomes were assessed with magnetic resonance imaging ( MRI ) or ultrasonography to determine the postoperative healing rates . RESULTS Baseline demographic data including age ( p = 0.29 ) , sex ( p = 0.68 ) , affected side ( p = 0.39 ) , and rotator cuff tear size ( p = 0.28 ) did not differ between groups . The WORC score did not differ significantly between groups at any time point ( p = 0.48 at baseline , p = 0.089 at three months , p = 0.52 at six months , p = 0.83 at twelve months , and p = 0.60 at twenty-four months ) . The WORC score at each postoperative time point was significantly better than the baseline value . The Constant score , ASES score , and strength did not differ significantly between groups at any time point . Logistic regression analysis demonstrated that a smaller initial tear size and double-row fixation were associated with higher healing rates . CONCLUSIONS No significant differences in functional or quality -of-life outcomes were identified between single-row and double-row fixation techniques . A smaller initial tear size and a double-row fixation technique were associated with higher healing rates as assessed with ultrasonography or MRI . LEVEL OF EVIDENCE Therapeutic level I. See Instructions for Authors for a complete description of levels of evidence Objectives To retrospectively evaluate fatty degeneration ( FD ) of rotator cuff muscles on CTA using Goutallier ’s grading system and quantitative measurements with comparison between pre- and postoperative states . Material s and methods IRB approval was obtained for this study . Two radiologists independently review ed pre- and postoperative CTAs of 43 patients ( 24 males and 19 females , mean age , 58.1 years ) with 46 shoulders confirmed as full-thickness tears with r and om distribution . FD of supraspinatus , infraspinatus/teres minor , and subscapularis was assessed using Goutallier ’s system and by quantitative measurements of Hounsfield units ( HUs ) on sagittal images . Changes in FD grade s and HUs were compared between pre- and postoperative CTAs and analyzed with respect to preoperative tear size and postoperative cuff integrity . The correlations between qualitative grade s and quantitative measurements and their inter-observer reliabilities were also assessed . Results There was statistically significant correlation between FD grade s and HU measurements of all muscles on pre- and postoperative CTA ( p < 0.05 ) . Inter-observer reliability of fatty degeneration grade s were excellent to substantial on both pre- and postoperative CTA in supraspinatus ( 0.8685 and 0.8535 ) and subscapularis muscles ( 0.7777 and 0.7972 ) , but fair in infraspinatus/teres minor muscles ( 0.5791 and 0.5740 ) ; however , quantitative Hounsfield units measurements showed excellent reliability for all muscles ( ICC : 0.7950 and 0.9346 for SST , 0.7922 and 0.8492 for SSC , and 0.9254 and 0.9052 for IST/TM ) . No muscle showed improvement of fatty degeneration after surgical repair on qualitative and quantitative assessment s ; there was no difference in changes of fatty degeneration after surgical repair according to preoperative tear size and post-operative cuff integrity ( p > 0.05 ) . The average dose-length product ( DLP , mGy · cm ) was 365.2 mGy · cm ( range , 323.8 - 417.2 mGy · cm ) and estimated average effective dose was 5.1 mSv . Conclusions Goutallier grade s correlated well with HUs of rotator cuff muscles . Reliability was excellent for both systems , except for FD grade of IST/TM muscles , which may be more reliably assessed using quantitative measurements In 13 patients , the development of supraspinatus muscle atrophy and fatty infiltration after rotator cuff tendon repair  was quantified prospect ively via magnetic resonance imaging . Intraoperative electrical nerve stimulation at repair showed that the maximal supraspinatus tension ( up to 200 N ) strongly correlated with the anatomic cross-sectional muscle area and with muscle fatty infiltration ( ranging from 12 N/cm(2 ) in Goutallier stage 3 to 42 N/cm(2 ) in Goutallier stage 0 ) . Within 1 year after successful tendon repair ( n = 8) , fatty infiltration did not recover , and atrophy improved partially at best ; however , if the repair failed ( n = 5 ) , atrophy and fatty infiltration progressed significantly . The ability of the rotator cuff muscles to develop tension not only correlates with their atrophy but also closely correlates with their degree of fatty infiltration . With current repair techniques , atrophy and fatty infiltration appear to be irreversible , despite successful tendon repair . Unexpectedly , not only weak but also very strong muscles are at risk for repair failure Background Subacromial impingement syndrome is a frequently observed disorder in orthopedic practice . Lasting symptoms and impairment may occur when a subsequent atraumatic rotator cuff rupture is also present . However , degenerative ruptures of the rotator cuff can also be observed in asymptomatic elderly individuals . Treatment of these symptomatic degenerative ruptures may be conservative or surgical . Acceptable results are reported for both treatment modalities . No evidence -based level-1 studies have been conducted so far to compare these treatment modalities . The objective of this study is to determine whether there is a difference in outcome between surgical reconstruction and conservative treatment of a degenerative atraumatic rotator cuff tendon rupture . Methods / Design A r and omized controlled trial will be conducted . Patients aged between 45 and 75 with a symptomatic atraumatic rotator cuff rupture as diagnosed by MRI will be included . Exclusion criteria are traumatic rotator cuff rupture , frozen shoulder and diabetes mellitus . Patients will be r and omized into two groups . Conservative treatment includes physical therapy according to a st and ardized protocol , NSAIDs and , if indicated , subacromial infiltration with a local anesthetic and corticosteroids . Surgical reconstruction is performed under general anesthesia in combination with an interscalenus plexus block . An acromioplasty with reconstruction of the rotator cuff tendon is performed , as described by Rockwood et al. Measurements take place preoperatively and 6 weeks , 3 months , 6 months and 1 year postoperatively . The primary outcome measure is the Constant score . Secondary measures include both disease-specific and generic outcome measures , and an economic evaluation . Additionally , one year after inclusion a second MRI will be taken of all patients in order to determine whether extent and localization of the rupture as well as the amount of fatty degeneration are prognostic factors . Discussion Both surgical as conservative treatment of a symptomatic atraumatic rotator cuff tendon rupture is used in current practice . There is a lack of level-1 studies comparing surgical vs. conservative treatment . This r and omized controlled trial has been design ed to determine whether the surgical treatment of a degenerative atraumatic rotator cuff tendon rupture may lead to a better functional and radiological outcome than conservative treatment after one year of follow-up . Trial registration numberNetherl and s Trial Register ( NTR ) : Purpose The purpose of this study was to compare arthroscopic rotator cuff repair with single-row and double-row techniques because research has demonstrated the superiority of double-row repair from a biological and 
    Output:
    
With the data available , only the presence of structural integrity showed good intra- and inter-observer agreement .