***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: Aim This experimental study aim ed to compare the load-to-failure rate and stiffness of single- versus double-row suture techniques for repairing rotator cuff lesions using two different suture material s. Additionally , the mode of failure of each repair was evaluated . Method In 32 sheep shoulders , a st and ardized tear of the infraspinatus tendon was created . Then , n = 8 specimen were r and omized to four repair methods : ( 1 ) Double-row Anchor Ethibond ® coupled with polyester sutures , USP No. 2 ; ( 2 ) Double-Row Anchor HiFi ® with polyblend polyethylene sutures , USP No. 2 ; ( 3 ) Single-Row Anchor Ethibond ® coupled with braided polyester sutures , USP No. 2 ; and ( 4 ) Single-Row Anchor HiFi ® with braided polyblend polyethylene sutures , USP No. 2 . Arthroscopic Mason – Allen stitches were placed ( single-row ) and combined with medial horizontal mattress stitches ( double-row ) . All specimens were loaded to failure at a constant displacement rate on a material testing machine . Results Group 4 showed lowest load-to-failure result with 155.7 ± 31.1 N compared to group 1 ( 293.4 ± 16.1 N ) and group 2 ( 397.7 ± 7.4 N ) ( P < 0.001 ) . Stiffness was highest in group 2 ( 162 ± 7.3 N/mm ) and lowest in group 4 ( 84.4 ± 19.9 mm ) ( P < 0.001 ) . In group 4 , the main cause of failure was due to the suture cutting through the tendon ( n = 6 ) , a failure case observed in only n = 1 specimen in group 2 ( P < 0.001 ) . Conclusions A double-row technique combined with arthroscopic Mason-Allen/horizontal mattress stitches provides high initial failure strength and may minimize the risk of the polyethylene sutures cutting through the tendon in rotator cuff repair when a single load force is used Background Recurrent defects after open and arthroscopic rotator cuff repair are common . Double-row repair techniques may improve initial fixation and quality of rotator cuff repair .  Purpose To evaluate the load to failure , cyclic displacement , and anatomical footprint of 4 arthroscopic rotator cuff repair techniques .  Hypothesis Double-row suture anchor repair would have superior structural properties and would create a larger footprint compared to single-row repair . Study Design Controlled laboratory study . Methods Twenty fresh-frozen cadaveric shoulders were r and omly assigned to 4 arthroscopic repair techniques . The repair was performed as either a single-row technique or 1 of 3 double-row techniques : diamond , mattress double anchor , or modified mattress double anchor . Angle of loading , anchor type , bone mineral density , anchor distribution , angle of anchor insertion , arthroscopic technique , and suture type and size were all controlled . Footprint length and width were quantified before and after repair . Displacement with cyclic loading and load to failure were determined . Results There were no differences in load to failure and displacement with cyclic loading between the single-row repair and each double-row repair . All repair groups demonstrated load to failure greater than 250 N. A significantly greater supraspinatus footprint width was seen with double-row techniques compared to single-row repair . Conclusions The single-row repair technique was similar to the double-row techniques in load to failure , cyclic displacement , and gap formation . The double-row anchor repairs consistently restored a larger footprint than did the single-row method . Clinical Relevance The arthroscopic techniques studied have strong structural properties that approached the reported performance of open repair techniques . Double-row techniques provide a larger footprint width ; although not addressed by this study , such a factor may improve the biological quality of repair The aim of the study was to evaluate the time zero contact pressure over a defined rotator cuff footprint using different repair and stitch techniques in an established sheep model . Forty fresh-frozen sheep shoulders were r and omly assigned to five repair groups : single-row repair using simple stitches ( SRA-s ) , single-row repair using horizontal mattress stitches ( SRA-m ) , and single-row repair using arthroscopic Mason-Allen stitches ( SRA-ama ) . Double-row repair was either performed with a combination of simple and horizontal mattress stitches ( DRA-sm ) or with arthroscopic Mason-Allen/horizontal mattress stitches ( DRA-amam ) . Investigations were performed using a pressure-sensitive film system . The average contact pressure and pressure pattern were measured for each group . Contact pressure was lowest in SRA-m followed by SRA-s . SRA-ama showed highest contact pressure of all single-row treatment groups ( P < 0.05 ) . DRA-amam presented the highest overall contact pressure ( P < 0.05 ) , whereas DRA-sm exerted contact pressure equal to that of SRA-ama . Both double-row techniques showed the most exp and ed pressure pattern . Average contact pressures for the more complex single- and double-row techniques utilizing arthroscopic Mason-Allen stitches were greater than were those of the repair techniques utilizing simple and horizontal mattress stitches . However , the contact pattern between the anchors could be increased by using the double-row technique , result ing in more footprint coverage compared to patterns utilizing the single-row techniques . These results support the use of the more complex arthroscopic Mason-Allen stitches and may improve the environment for healing of the repaired rotator cuff tendon The purpose of this study was to identify potential predictors of function and tendon healing after  arthroscopic rotator cuff repair  that will enable the orthopaedic surgeon to determine which patients can expect a successful outcome . Between 2003 and 2005 , the Arthroscopic Rotator Cuff Registry was established to collect demographic , intraoperative , functional outcome , and ultrasound data prospect ively on all patients who underwent primary arthroscopic rotator cuff repair . At total of 193 patients met the study criteria , and 127 ( 65.8 % ) completed the 2-year follow-up . The most significant independent factors affecting  ultrasound outcome were age ( odds ratio [ OR ] , 1.08 ; 95 % confidence interval [ CI ] , 1.02 - 1.14 ; P = .006 ) and tear size ( OR , 2.29 ; 95 % CI , 1.55 - 3.38 ; P < .001 ) . After adjustment for age and tear size , the intraoperative factors found to be significantly associated with a tendon defect were concomitant biceps procedures ( OR , 11.39 ; 95 % CI , 2.90 - 44.69 ; P < .001 ) and acromioclavicular joint procedures ( OR , 3.85 ; 95 % CI , 1.46 - 10.12 ; P = .006 ) . In contrast to the ultrasound data , the functional outcome variables , such as satisfaction ( OR , 3.92 ; 95 % CI , 2.00 - 7.68 ; P < .001 ) and strength ( OR , 10.05 ; 95 % CI , 1.61 - 62.77 ; P = .01 ) , had a greater role in predicting an American Shoulder and Elbow Surgeons score greater than 90 . The progression from a single-tendon rotator cuff tear to a multiple-tendon tear with associated pathology increased the likelihood of tendon defect by at least 9 times , and therefore , earlier surgical intervention for isolated , single-tendon rotator cuff tears could optimize the likelihood of ultrasound healing and an excellent functional outcome PURPOSE The purpose of this study was to determine biomechanical differences in cyclic elongation and ultimate strength between double-row rotator cuff repair  and single-row repair  for partial rotator cuff repairs . METHODS We r and omly assigned 18 immature bovine specimens ( aged 12 to 16 weeks ) to 3 repair groups ( 6 per group ) . A 1 x 2-cm defect was created at the infraspinatus tendon insertion site . Two suture anchors were implanted 1 cm apart at the anatomic insertion area for the lateral row . Two suture anchors were implanted 1 cm medial to the lateral row and 1 cm apart from each other for the medial row . Repair groups were constructed as follows : single-row repair with double-loaded suture anchors ( group 1 ) , double-row repair with single-loaded medial row and double-loaded lateral row ( group 2 ) , and double-row repair with single-loaded medial row and single-loaded lateral row ( group 3 ) . Specimens were cyclically loaded from 10 N to 90 N for 500 cycles and then loaded at 0.5 mm/s to failure . Data for cyclic elongation , with loads at 3 mm , 5 mm , and 10 mm , were analyzed via a 1-way analysis of variance ( P < .05 ) . RESULTS There were no significant differences for peak elongation after cyclic loading between groups . There were no significant differences between repair groups for loads at 3 mm , 5 mm , and 10 mm of elongation . Constructs typically failed by knot slippage ( 83 % ) , with a single sample having tendon-suture failure ( 17 % ) . CONCLUSIONS Double-row repair did not show a biomechanical advantage compared with single-row repair . With this result in mind , the theoretic advantage of a potentially larger footprint must be balanced against the added surgical time , complexity , and cost of double-row repair . CLINICAL RELEVANCE Arthroscopic surgeons should choose the best form of fixation for a given patient , without undue emphasis on single-row repair versus double-row repair . The clinical and biologic impact of footprint restoration was not addressed in this study The aim of the study was to evaluate the time zero mechanical properties of single- versus double-row configuration for rotator cuff repair in an animal model with consideration of the stitch technique and suture material . Thirty-two fresh-frozen sheep shoulders were r and omly assigned to four repair groups : suture anchor single-row repair coupled with ( 1 ) braided , nonabsorbable polyester suture sized USP No. 2 ( SRAE ) or ( 2 ) braided polyblend polyethylene suture sized No. 2 ( SRAH ) . The double-row repair was coupled with ( 3 ) USP No. 2 ( DRAE ) or ( 4 ) braided polyblend polyethylene suture No. 2 ( DRAH ) . Arthroscopic Mason – Allen stitches were used ( single-row ) and combined with medial horizontal mattress stitches ( double-row ) . Shoulders were cyclically loaded from 10 to 180 N. Displacement to gap formation of 5- and 10-mm at the repair site , cycles to failure , and the mode of failure were determined . The ultimate tensile strength was verified in specimens that resisted to 3,000 cycles . DRAE and DRAH had a lower frequency of 5- ( P = 0.135 ) and 10-mm gap formation ( P = 0.135 ) . All DRAE and DRAH resisted 3,000 cycles while only three SRAE and one SRAH resisted 3,000 cycles ( P < 0.001 ) . The ultimate tensile strength in double-row specimens was significantly higher than in others ( P < 0.001 ) . There was no significant variation in using different suture material ( P > 0.05 ) . Double-row suture anchor repair with arthroscopic Mason – Allen/medial mattress stitches provides initial strength superior to single-row repair with arthroscopic Mason – Allen stitches under isometric cyclic loading as well as under ultimate loading conditions . Our results support the concept of double-row fixation with arthroscopic Mason – Allen/medial mattress stitches in rotator cuff tears with improvement of initial fixation strength and ultimate tensile load . Use of new polyblend polyethylene suture material seems not to increase the initial biomechanical aspects of the repair construct The reported functional results of rotator cuff repair performed arthroscopically have been good . Only little is known about the cuff integrity after arthroscopic repair and how it influences the outcome . The aim of the study is to set a baseline of what rate of healing response respectively re-tears to expect and how cuff integrity alters the outcome . Fifty-three consecutive patients with an isolated supraspinatus tendon tear were arthroscopically operated and their tendons repaired . All pre- and postoperative data were prospect ively collected . At a minimum follow-up after 24 months ( average 26.4 months ) , the integrity of the cuff was evaluated by an open magnetic resonance imaging and the patients ’ function and satisfaction were documented and grade d to the sex- and age-related Constant-score also using a dynamometer for strength testing . The re-tear rate was 24.5 % with 13 non-healed tendons . The Constant-score of all patients improved significantly . The scores of the patients with a re-tear were significantly lower than those of the patient with an intact cuff . That was due to a less good performance in strength testing . The other categories of the Constant-score did not show any differences . The age of the patients with a re-tear was significantly higher . With the exception of age , we did not find any negative prognostic factor for a re-tear , and with the exception of re-tear no other factor influenced the Constant-score .  Arthroscopic supraspinatus tendon repair yields a re-tear rate of 25 % which is comparable with the results of open or mini/open repair . Cuff integrity influences postoperative strength and Constant-score .  Patients older than 65 years show a higher re-tear rate . Therapeutic Level IV is the level of evidence Th 
    Output:
    
Traditional open rotator cuff repairs using tranosseous bone tunnels had the advantage of reapproximating the rotator cuff tendon solidly onto the greater tuberosity