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Journal of Shoulder and Elbow Surgery

Risk factors affecting rotator cuff retear after arthroscopic repair: a meta-analysis and systematic review

  • Author Footnotes
    1 These authors contributed equally to this work.
    Jinlong Zhao
    Footnotes
    1 These authors contributed equally to this work.
    Affiliations
    The Second School of Clinical Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China

    Research Team on Bone and Joint Degeneration and Injury, Guangdong Academy of Traditional Chinese Medicine, Guangzhou, China
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  • Author Footnotes
    1 These authors contributed equally to this work.
    Minghui Luo
    Footnotes
    1 These authors contributed equally to this work.
    Affiliations
    Research Team on Bone and Joint Degeneration and Injury, Guangdong Academy of Traditional Chinese Medicine, Guangzhou, China

    The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou, China
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  • Author Footnotes
    1 These authors contributed equally to this work.
    Jianke Pan
    Footnotes
    1 These authors contributed equally to this work.
    Affiliations
    Research Team on Bone and Joint Degeneration and Injury, Guangdong Academy of Traditional Chinese Medicine, Guangzhou, China

    The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou, China
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  • Guihong Liang
    Affiliations
    Research Team on Bone and Joint Degeneration and Injury, Guangdong Academy of Traditional Chinese Medicine, Guangzhou, China

    The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou, China
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  • Wenxuan Feng
    Affiliations
    The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou, China
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  • Lingfeng Zeng
    Affiliations
    Research Team on Bone and Joint Degeneration and Injury, Guangdong Academy of Traditional Chinese Medicine, Guangzhou, China

    The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou, China
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  • Weiyi Yang
    Correspondence
    Reprint requests: Weiyi Yang, MD, PhD and Jun Liu, MD, PhD, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou 510120, China.
    Affiliations
    Research Team on Bone and Joint Degeneration and Injury, Guangdong Academy of Traditional Chinese Medicine, Guangzhou, China

    The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou, China
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  • Jun Liu
    Correspondence
    Reprint requests: Weiyi Yang, MD, PhD and Jun Liu, MD, PhD, The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou 510120, China.
    Affiliations
    Research Team on Bone and Joint Degeneration and Injury, Guangdong Academy of Traditional Chinese Medicine, Guangzhou, China

    The Second Affiliated Hospital, Guangzhou University of Chinese Medicine (Guangdong Province Hospital of Traditional Chinese Medicine), Guangzhou, China
    Search for articles by this author
  • Author Footnotes
    1 These authors contributed equally to this work.
Open AccessPublished:June 01, 2021DOI:https://doi.org/10.1016/j.jse.2021.05.010

      Background

      Retear after arthroscopic rotator cuff repair (ARCR) consistently challenges medical staff and patients, and the incidence of retear after surgery is 10%-94%. The purpose of this study was to identify the risk factors that cause retear after ARCR and provide theoretical guidance for clinical intervention to reduce the occurrence of postoperative rotator cuff retear.

      Methods

      The protocol for this meta-analysis was registered with PROSPERO (CRD42021225088). PubMed, Web of Science, and Embase were searched for observational studies on risk factors for rotator cuff retear after arthroscopic repair. Meta-analytical methods were used to determine the odds ratio or weighted mean difference of potential risk factors related to postoperative rotator cuff retear. Stata 15.1 was used to quantitatively evaluate the publication bias of the statistical results.

      Results

      Fourteen studies from 6 countries with a total of 5693 patients were included. The meta-analysis revealed that the risk factors for retear after rotator cuff repair were age, body mass index, diabetes, subscapularis and infraspinatus fatty infiltration, symptom duration, bone mineral density, tear length, tear width, tear size area, amount of retraction, critical shoulder angle, acromiohumeral interval, distance from the musculotendinous junction to the glenoid, operative duration, biceps procedure, and postoperative University of California Los Angeles shoulder score.

      Conclusion

      These findings can help clinical medical staff identify patients who are prone to retear early after arthroscopic repair and develop targeted prevention and treatment strategies for modifiable risk factors, which are of great significance for reducing the occurrence of rotator cuff retear after ARCR.

      Level of evidence

      Keywords

      Rotator cuff tears (RCTs) are one of the main causes of shoulder joint pain and mobility disorders, accounting for approximately 50% of shoulder joint diseases.
      • Mazzocca A.D.
      • Arciero R.A.
      • Shea K.P.
      • Apostolakos J.M.
      • Solovyova O.
      • Gomlinski G.
      • et al.
      The effect of early range of motion on quality of life, clinical outcome, and repair integrity after arthroscopic rotator cuff repair.
      The incidence of rotator cuff injury gradually increases with age. Approximately 25.6% of people aged ≥60 years experience rotator cuff injury, and this prevalence is as high as 45.8% for people aged ≥70 years.
      • Cho N.S.
      • Moon S.C.
      • Jeon J.W.
      • Rhee Y.G.
      The influence of diabetes mellitus on clinical and structural outcomes after arthroscopic rotator cuff repair.
      With the development of arthroscopic technology, arthroscopic rotator cuff repair (ARCR) has become the main method for treating RCTs.
      • Denard P.J.
      • Lädermann A.
      • Burkhart S.S.
      Prevention and management of stiffness after arthroscopic rotator cuff repair: systematic review and implications for rotator cuff healing.
      ,
      • O'Donnell E.A.
      • Fu M.C.
      • White A.E.
      • Taylor S.A.
      • Dines J.S.
      • Dines D.M.
      • et al.
      The effect of patient characteristics and comorbidities on the rate of revision rotator cuff repair.
      Each year, 4.5 million patients in the United States visit a doctor because of rotator cuff injury; nearly 250,000 of these cases are treated through surgical repair, of which arthroscopic surgery accounts for more than 95%, and the related treatment and rehabilitation costs are as high as 7 billion US dollars.
      • Garcia G.H.
      • Liu J.N.
      • Wong A.
      • Cordasco F.
      • Dines D.M.
      • Dines J.S.
      • et al.
      Hyperlipidemia increases the risk of retear after arthroscopic rotator cuff repair.
      The retear rate after ARCR is 10%-48.4%,
      • Crim J.
      • Burks R.
      • Manaster B.J.
      • Hanrahan C.
      • Hung M.
      • Greis P.
      Temporal evolution of MRI findings after arthroscopic rotator cuff repair.
      ,
      • Flurin P.H.
      • Hardy P.
      • Abadie P.
      • Boileau P.
      • Collin P.
      • Deranlot J.
      • et al.
      Arthroscopic repair of the rotator cuff: prospective study of tendon healing after 70 years of age in 145 patients.
      ,
      • Hug K.
      • Gerhardt C.
      • Haneveld H.
      • Scheibel M.
      Arthroscopic knotless-anchor rotator cuff repair: a clinical and radiological evaluation.
      ,
      • Kim H.M.
      • Caldwell J.M.
      • Buza J.A.
      • Fink L.A.
      • Ahmad C.S.
      • Bigliani L.U.
      • et al.
      Factors affecting satisfaction and shoulder function in patients with a recurrent rotator cuff tear.
      ,
      • Shin S.
      • Kook S.
      • Rao N.
      • Seo M.
      Clinical outcomes of modified Mason-Allen single-row repair for bursal-sided partial-thickness rotator cuff tears: comparison with the double-row suture-bridge technique.
      and the retear rate after arthroscopic repair of massive rotator cuff injuries is as high as 94%.
      • Galatz L.M.
      • Ball C.M.
      • Teefey S.A.
      • Middleton W.D.
      • Yamaguchi K.
      The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears.
      ,
      • Garcia G.H.
      • Liu J.N.
      • Wong A.
      • Cordasco F.
      • Dines D.M.
      • Dines J.S.
      • et al.
      Hyperlipidemia increases the risk of retear after arthroscopic rotator cuff repair.
      Compared with primary rotator cuff repair, rotator cuff revision is more difficult, time-consuming, and less effective.
      • Kim H.M.
      • Caldwell J.M.
      • Buza J.A.
      • Fink L.A.
      • Ahmad C.S.
      • Bigliani L.U.
      • et al.
      Factors affecting satisfaction and shoulder function in patients with a recurrent rotator cuff tear.
      ,
      • Namdari S.
      • Donegan R.P.
      • Chamberlain A.M.
      • Galatz L.M.
      • Yamaguchi K.
      • Keener J.D.
      Factors affecting outcome after structural failure of repaired rotator cuff tears.
      The curative effect of secondary repair after retear is far lower than expected, and patient satisfaction is significantly decreased.
      • Namdari S.
      • Donegan R.P.
      • Chamberlain A.M.
      • Galatz L.M.
      • Yamaguchi K.
      • Keener J.D.
      Factors affecting outcome after structural failure of repaired rotator cuff tears.
      Therefore, it is very important to identify high-risk populations and pay attention to the risk assessment of patients with rotator cuff retear.
      Before the operation, a risk assessment of the influencing factors of patients with postoperative retear should be performed to develop the best treatment measures, which is particularly critical for the diagnosis and treatment of patients with RCTs. Some studies have revealed that the cause of rotator cuff retear after ARCR may be related to factors such as age, diabetes, gout, hyperlipidemia, physical labor, and low education level,
      • Borton Z.
      • Shivji F.
      • Simeen S.
      • Williams R.
      • Tambe A.
      • Espag M.
      • et al.
      Diabetic patients are almost twice as likely to experience complications from arthroscopic rotator cuff repair.
      ,
      • Huang S.
      • Wu C.
      • Lin L.
      • Liou T.
      • Lin H.
      Gout can increase the risk of receiving rotator cuff tear repair surgery.
      ,
      • Kim H.M.
      • Caldwell J.M.
      • Buza J.A.
      • Fink L.A.
      • Ahmad C.S.
      • Bigliani L.U.
      • et al.
      Factors affecting satisfaction and shoulder function in patients with a recurrent rotator cuff tear.
      ,
      • Namdari S.
      • Donegan R.P.
      • Chamberlain A.M.
      • Galatz L.M.
      • Yamaguchi K.
      • Keener J.D.
      Factors affecting outcome after structural failure of repaired rotator cuff tears.
      but some risk factors are contradictory across different studies. Therefore, this study used a quantitative, systematic evaluation method to analyze the risk factors for rotator cuff retear after arthroscopic repair and to clarify the risk factors that affect rotator cuff retear.

      Methods

      This meta-analysis was performed in strict accordance with the relevant requirements of the Meta-analysis of Observational Studies in Epidemiology (MOOSE) statement (Supplementary Material S1)
      • Stroup D.F.
      • Berlin J.A.
      • Morton S.C.
      • Olkin I.
      • Williamson G.D.
      • Rennie D.
      • et al.
      Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group.
      and was registered with the PROSPERO International Prospective Register of Systematic Reviews (registration number CRD42021225088).

       Literature inclusion and exclusion criteria

      The following inclusion criteria were applied: (1) All included patients needed to undergo arthroscopic repair. (2) The case groups were defined as patients with rotator cuff retear after surgery, and the control groups comprised patients with rotator cuff healing. (3) The investigations were designed as cohort studies, case-control studies, or cross-sectional studies that were clearly divided into case groups and control groups to compare exposure factors. (4) The studies included at least 1 evaluation index. (5) The included evaluation indicators were reported in at least 2 literature studies. (6) The publication language was not limited.
      The exclusion criteria were as follows: (1) The research was repetitively published literature. (2) The data reported in the article or the original data obtained could not be converted and merged. (3) The publication was a review or a case report. (4) The quality of the literature was too low (New Castle-Ottawa Scale [NOS] score <4 points or Agency for Healthcare Research and Quality score <4 points).

       Search strategy

      A computer search of 3 databases, namely, PubMed, Web of Science, and Embase, was performed. The search adopted a combination of subject terms and free words, and the search time extended from the establishment of each database to October 2020. In addition, the references of the included literature were traced to supplement the further acquisition of relevant literature. The main search terms included risk factor, factor risk, population at risk, rotator cuff, subscapularis, infraspinatus, arthroscopic repair, rotator cuff repair, and arthroscopy. See Supplementary Material S2 for the search strategy used in each database.

       Literature screening and data extraction

      Two researchers independently screened the literature and extracted and cross-checked the data. Disagreements were resolved through discussion or negotiation with a third party. When selecting documents, the researchers read the title first, and after excluding obviously irrelevant documents, they read the abstract and full text to determine whether to include the publication. If necessary, the original research authors were contacted via e-mail or telephone to obtain information that had not yet been determined but was important to this research. The extracted information included the following: (1) basic information of the included research, including first author, publication time, and research type; (2) baseline characteristics of the research object, including sample, and age; (3) key elements of the bias risk evaluation; and (4) the outcome indicators and measurement data of concern.

       Evaluation of literature quality

      The types of documents included in this article were cohort studies, case-control studies, and cross-sectional studies. The NOS was adopted to evaluate the risk of bias for the case-control studies and cohort studies.
      • Wells G.A.
      • Shea B.
      • O’Connell D.
      • et al.
      The Newcastle-Ottawa Scale (NOS) for assessing the quality if nonrandomized studies in metaanalyses.
      The evaluation includes 3 parts: study object selection, intergroup comparability, and outcome measurement. The total score is 9 points. The higher the score, the better the quality of the literature. Cross-sectional studies were evaluated using the risk of bias evaluation criteria recommended by the Agency for Healthcare Research and Quality.
      • Cho N.S.
      • Moon S.C.
      • Jeon J.W.
      • Rhee Y.G.
      The influence of diabetes mellitus on clinical and structural outcomes after arthroscopic rotator cuff repair.
      There are 11 items in total, and each item is answered with “yes,” “no,” or “not clear.”
      • Chou R.
      • Baker W.L.
      • Bañez L.L.
      • Iyer S.
      • Myers E.R.
      • Newberry S.
      • et al.
      Agency for healthcare research and quality evidence-based practice center methods provide guidance on prioritization and selection of harms in systematic reviews.

       Statistical analysis

      RevMan 5.3 software was used for the meta-analysis. The weighted mean difference (WMD) was employed as the effect size for measurement data, and the odds ratio (OR) was used for binary variables. Each effect size is provided with its 95% confidence interval (CI). The heterogeneity of the included studies was evaluated by the heterogeneity test. If there was no heterogeneity (I2 ≤ 50%), the fixed effects model was used to merge the effect sizes. If there was heterogeneity (I2 > 50%), the random effects model was used to merge the effect sizes. According to the characteristics of the research object, sample size, research design type, etc, a subgroup analysis or sensitivity analysis was conducted to find the source of heterogeneity. For outcome indicators with more than 7 articles included, Stata 15.1 software was used to perform Egger linear regression test to evaluate publication bias.

      Results

       Literature screening process and results

      A total of 1299 articles were initially retrieved, including 405 articles from PubMed, 162 articles from Embase, 715 articles from Web of Science, and 17 articles from other sources. After excluding duplicate articles, 307 articles remained. After reading the title and abstract, 237 studies that clearly did not meet the requirements were excluded, and 70 documents were initially screened. After further reading the full text, according to the inclusion and exclusion criteria established in this study, 14 documents were finally included.
      • Chung S.W.
      • Oh J.H.
      • Gong H.S.
      • Kim J.Y.
      • Kim S.H.
      Factors affecting rotator cuff healing after arthroscopic repair.
      ,
      • Diebold G.
      • Lam P.
      • Walton J.
      • Murrell G.A.C.
      Relationship between age and rotator cuff retear.
      ,
      • Garcia G.H.
      • Liu J.N.
      • Wong A.
      • Cordasco F.
      • Dines D.M.
      • Dines J.S.
      • et al.
      Hyperlipidemia increases the risk of retear after arthroscopic rotator cuff repair.
      ,
      • Huang S.
      • Wu C.
      • Lin L.
      • Liou T.
      • Lin H.
      Gout can increase the risk of receiving rotator cuff tear repair surgery.
      ,
      • Jeong H.Y.
      • Kim H.J.
      • Jeon Y.S.
      • Rhee Y.G.
      Factors predictive of healing in large rotator cuff tears: is it possible to predict retear preoperatively?.
      ,
      • Kim I.B.
      • Kim M.W.
      Risk factors for retear after arthroscopic repair of full-thickness rotator cuff tears using the suture bridge technique: classification system.
      ,
      • Kim Y.
      • Jung K.
      • Kim J.
      • Kim U.
      • Hwang D.
      Factors affecting rotator cuff integrity after arthroscopic repair for medium-sized or larger cuff tears: a retrospective cohort study.
      • Kwon J.
      • Kim S.H.
      • Lee Y.H.
      • Kim T.I.
      • Oh J.H.
      The rotator cuff healing index: a new scoring system to predict rotator cuff healing after surgical repair.
      • Le B.T.N.
      • Wu X.L.
      • Lam P.H.
      • Murrell G.A.C.
      Factors predicting rotator cuff retears: an analysis of 1000 consecutive rotator cuff repairs.
      ,
      • Lee Y.S.
      • Jeong J.Y.
      • Park C.
      • Kang S.G.
      • Yoo J.C.
      Evaluation of the risk factors for a rotator cuff retear after repair surgery.
      ,
      • Lobo-Escolar L.
      • Ramazzini-Castro R.
      • Codina-Grañó D.
      • Lobo E.
      • Minguell-Monyart J.
      • Ardèvol J.
      Risk factors for symptomatic retears after arthroscopic repair of full-thickness rotator cuff tears.
      ,
      • Namdari S.
      • Donegan R.P.
      • Chamberlain A.M.
      • Galatz L.M.
      • Yamaguchi K.
      • Keener J.D.
      Factors affecting outcome after structural failure of repaired rotator cuff tears.
      ,
      • Park J.S.
      • Park H.J.
      • Kim S.H.
      • Oh J.H.
      Prognostic factors affecting rotator cuff healing after arthroscopic repair in small to medium-sized tears.
      ,
      • Tashjian R.Z.
      • Hollins A.M.
      • Kim H.M.
      • Teefey S.A.
      • Middleton W.D.
      • Steger-May K.
      • et al.
      Factors affecting healing rates after arthroscopic double-row rotator cuff repair.
      The specific retrieval process and results are shown in Fig. 1. This study included 10 retrospective cohort studies and 4 case-control studies. A total of 5693 patients from 6 countries were enrolled, including 4779 in the rotator cuff healing group and 914 in the retear group. The specific conditions of the included literature are shown in Table I.
      Figure thumbnail gr1
      Figure 1Flowchart of the number of studies identified and included in this meta-analysis.
      Table ICharacteristics of the included studies
      Included studies (first author/year)CountryStudy designNo. of patientsAP tear size
      Values are expressed as mean.
      , cm
      Age, yrSymptom duration,
      Values are expressed as mean.
      mo
      Imaging modalityTime to imaging, moIncidence of retear, %Level of evidenceNOS
      RetearHealedRetearHealedRetearHealedRetearHealed
      Le (2014)
      • Le B.T.N.
      • Wu X.L.
      • Lam P.H.
      • Murrell G.A.C.
      Factors predicting rotator cuff retears: an analysis of 1000 consecutive rotator cuff repairs.
      AustraliaRC1748262.81.665.7 ± 10.457.6 ± 11.7NRNRUS617.47
      Diebold (2017)
      • Diebold G.
      • Lam P.
      • Walton J.
      • Murrell G.A.C.
      Relationship between age and rotator cuff retear.
      AustraliaRC21213882.81.765 ± 11.6558 ± 11.8NRNRUS6138
      Garcia (2016)
      • Garcia G.H.
      • Liu J.N.
      • Wong A.
      • Cordasco F.
      • Dines D.M.
      • Dines J.S.
      • et al.
      Hyperlipidemia increases the risk of retear after arthroscopic rotator cuff repair.
      USARC1157NRNRNRNRNRNRUS716.16
      Jeong (2018)
      • Jeong H.Y.
      • Kim H.J.
      • Jeon Y.S.
      • Rhee Y.G.
      Factors predictive of healing in large rotator cuff tears: is it possible to predict retear preoperatively?.
      KoreaCS51513.33.266.4 ± 6.664.9 ± 6.632.217.8MRI9467
      Kim (2016)
      • Kim I.B.
      • Kim M.W.
      Risk factors for retear after arthroscopic repair of full-thickness rotator cuff tears using the suture bridge technique: classification system.
      KoreaRC37245NRNRNRNRNRNRMRI613.18
      Park (2015)
      • Park J.S.
      • Park H.J.
      • Kim S.H.
      • Oh J.H.
      Prognostic factors affecting rotator cuff healing after arthroscopic repair in small to medium-sized tears.
      KoreaCS45294NRNR63.2 ± 7.159.2 ± 7.843.631.1MRI1213.38
      Kwon (2018)
      • Kwon J.
      • Kim S.H.
      • Lee Y.H.
      • Kim T.I.
      • Oh J.H.
      The rotator cuff healing index: a new scoring system to predict rotator cuff healing after surgical repair.
      KoreaCS1454582.81.764.1 ± 7.559.4 ± 8.239.426.3CT or MRI12247
      Lobo-Escolar (2020)
      • Lobo-Escolar L.
      • Ramazzini-Castro R.
      • Codina-Grañó D.
      • Lobo E.
      • Minguell-Monyart J.
      • Ardèvol J.
      Risk factors for symptomatic retears after arthroscopic repair of full-thickness rotator cuff tears.
      SpainRC15143NRNR52.5 ± 7.252.3 ± 6.810.78.7MRI89.58
      Harada (2020)
      • Harada N.
      • Gotoh M.
      • Ishitani E.
      • et al.
      Combination of risk factors affecting retear after arthroscopic rotator cuff repair: a decision tree analysis.
      JapanRC322543.42.666.8 ± 5.464.7 ± 7.312.69.3MRI611.199
      Tashjian (2010)
      • Tashjian R.Z.
      • Hollins A.M.
      • Kim H.M.
      • Teefey S.A.
      • Middleton W.D.
      • Steger-May K.
      • et al.
      Factors affecting healing rates after arthroscopic double-row rotator cuff repair.
      USACS2425NRNR63.3 ± 1055.1 ± 10NRNRUS6NR8
      Chung (2011)
      • Chung S.W.
      • Oh J.H.
      • Gong H.S.
      • Kim J.Y.
      • Kim S.H.
      Factors affecting rotator cuff healing after arthroscopic repair.
      KoreaRC622102.71.765.0 ± 7.658.2 ± 7.54933.2CT or US1222.88
      Namdari (2014)
      • Namdari S.
      • Donegan R.P.
      • Chamberlain A.M.
      • Galatz L.M.
      • Yamaguchi K.
      • Keener J.D.
      Factors affecting outcome after structural failure of repaired rotator cuff tears.
      USARC28332.52.260.3 ± 8.362.2 ± 8.5NRNRMRI or US12337
      Lee (2017)
      • Lee Y.S.
      • Jeong J.Y.
      • Park C.
      • Kang S.G.
      • Yoo J.C.
      Evaluation of the risk factors for a rotator cuff retear after repair surgery.
      KoreaRC50643NRNR64.6 ± 7.7559.1 ± 12.7NRNRMRI127.229
      Kim (2017)
      • Kim Y.
      • Jung K.
      • Kim J.
      • Kim U.
      • Hwang D.
      Factors affecting rotator cuff integrity after arthroscopic repair for medium-sized or larger cuff tears: a retrospective cohort study.
      KoreaRC281524.13.161.8 ± 1.460.1 ± 0.620.415.7MRI2415.68
      RC, retrospective cohort study; CS, case-control study; AP, anteroposterior; NR, not reported; US, ultrasonography; MRI, magnetic resonance imaging; CT, computed tomography; NOS, New Castle-Ottawa scale.
      Values are expressed as mean.

       Literature quality evaluation

      The publications included in this study comprised retrospective cohort studies and case-control studies, and the NOS was used to evaluate the quality of the literature. The quality evaluation results of the included literature are shown in Table I. The NOS score of the included literature was between 6 and 9 points. Only 1 article
      • Garcia G.H.
      • Liu J.N.
      • Wong A.
      • Cordasco F.
      • Dines D.M.
      • Dines J.S.
      • et al.
      Hyperlipidemia increases the risk of retear after arthroscopic rotator cuff repair.
      had an NOS score of 6, and the average NOS score was 7.7 points, which indicates that the quality of the included literature was very high. The literature quality evaluation details of the 14 included studies
      • Chung S.W.
      • Oh J.H.
      • Gong H.S.
      • Kim J.Y.
      • Kim S.H.
      Factors affecting rotator cuff healing after arthroscopic repair.
      ,
      • Diebold G.
      • Lam P.
      • Walton J.
      • Murrell G.A.C.
      Relationship between age and rotator cuff retear.
      ,
      • Garcia G.H.
      • Liu J.N.
      • Wong A.
      • Cordasco F.
      • Dines D.M.
      • Dines J.S.
      • et al.
      Hyperlipidemia increases the risk of retear after arthroscopic rotator cuff repair.
      ,
      • Huang S.
      • Wu C.
      • Lin L.
      • Liou T.
      • Lin H.
      Gout can increase the risk of receiving rotator cuff tear repair surgery.
      ,
      • Jeong H.Y.
      • Kim H.J.
      • Jeon Y.S.
      • Rhee Y.G.
      Factors predictive of healing in large rotator cuff tears: is it possible to predict retear preoperatively?.
      ,
      • Kim I.B.
      • Kim M.W.
      Risk factors for retear after arthroscopic repair of full-thickness rotator cuff tears using the suture bridge technique: classification system.
      ,
      • Kim Y.
      • Jung K.
      • Kim J.
      • Kim U.
      • Hwang D.
      Factors affecting rotator cuff integrity after arthroscopic repair for medium-sized or larger cuff tears: a retrospective cohort study.
      • Kwon J.
      • Kim S.H.
      • Lee Y.H.
      • Kim T.I.
      • Oh J.H.
      The rotator cuff healing index: a new scoring system to predict rotator cuff healing after surgical repair.
      • Le B.T.N.
      • Wu X.L.
      • Lam P.H.
      • Murrell G.A.C.
      Factors predicting rotator cuff retears: an analysis of 1000 consecutive rotator cuff repairs.
      ,
      • Lee Y.S.
      • Jeong J.Y.
      • Park C.
      • Kang S.G.
      • Yoo J.C.
      Evaluation of the risk factors for a rotator cuff retear after repair surgery.
      ,
      • Lobo-Escolar L.
      • Ramazzini-Castro R.
      • Codina-Grañó D.
      • Lobo E.
      • Minguell-Monyart J.
      • Ardèvol J.
      Risk factors for symptomatic retears after arthroscopic repair of full-thickness rotator cuff tears.
      ,
      • Namdari S.
      • Donegan R.P.
      • Chamberlain A.M.
      • Galatz L.M.
      • Yamaguchi K.
      • Keener J.D.
      Factors affecting outcome after structural failure of repaired rotator cuff tears.
      ,
      • Park J.S.
      • Park H.J.
      • Kim S.H.
      • Oh J.H.
      Prognostic factors affecting rotator cuff healing after arthroscopic repair in small to medium-sized tears.
      ,
      • Tashjian R.Z.
      • Hollins A.M.
      • Kim H.M.
      • Teefey S.A.
      • Middleton W.D.
      • Steger-May K.
      • et al.
      Factors affecting healing rates after arthroscopic double-row rotator cuff repair.
      are shown in Supplementary Material S3.

       Meta-analysis results

       Sociodemographic risk factors

      This study conducted a statistical analysis of 15 sociodemographic factors (Table II) and then evaluated their impact on rotator cuff healing after ARCR. Eight studies reported on the correlation of age with rotator cuff healing after arthroscopic repair. The results of the studies had high heterogeneity (I2 = 93%), and the random effects model was used for analysis. The results showed that the correlation between age and rotator cuff retear was statistically significant (WMD 4.38, 95% CI 2.16, 6.61; P < .001). Meta-analysis showed that rotator cuff retear was more likely with increasing body mass index (BMI) (WMD 0.52, 95% CI 0.23, 0.82; P < .001). A total of 7 studies
      • Chung S.W.
      • Oh J.H.
      • Gong H.S.
      • Kim J.Y.
      • Kim S.H.
      Factors affecting rotator cuff healing after arthroscopic repair.
      ,
      • Harada N.
      • Gotoh M.
      • Ishitani E.
      • et al.
      Combination of risk factors affecting retear after arthroscopic rotator cuff repair: a decision tree analysis.
      ,
      • Kim Y.
      • Jung K.
      • Kim J.
      • Kim U.
      • Hwang D.
      Factors affecting rotator cuff integrity after arthroscopic repair for medium-sized or larger cuff tears: a retrospective cohort study.
      ,
      • Kwon J.
      • Kim S.H.
      • Lee Y.H.
      • Kim T.I.
      • Oh J.H.
      The rotator cuff healing index: a new scoring system to predict rotator cuff healing after surgical repair.
      ,
      • Lobo-Escolar L.
      • Ramazzini-Castro R.
      • Codina-Grañó D.
      • Lobo E.
      • Minguell-Monyart J.
      • Ardèvol J.
      Risk factors for symptomatic retears after arthroscopic repair of full-thickness rotator cuff tears.
      ,
      • Namdari S.
      • Donegan R.P.
      • Chamberlain A.M.
      • Galatz L.M.
      • Yamaguchi K.
      • Keener J.D.
      Factors affecting outcome after structural failure of repaired rotator cuff tears.
      ,
      • Park J.S.
      • Park H.J.
      • Kim S.H.
      • Oh J.H.
      Prognostic factors affecting rotator cuff healing after arthroscopic repair in small to medium-sized tears.
      ,
      • Tashjian R.Z.
      • Hollins A.M.
      • Kim H.M.
      • Teefey S.A.
      • Middleton W.D.
      • Steger-May K.
      • et al.
      Factors affecting healing rates after arthroscopic double-row rotator cuff repair.
      reported the impact of diabetes on rotator cuff healing. Meta-analysis showed that diabetes was a risk factor for retear after ARCR (OR 1.42, 95% CI 1.02, 1.97; P = .04). The results showed that male sex, female sex, the dominant hand, the affected shoulder, a high exercise level, hypertension, cardiovascular disease, hyperlipidemia, smoking, and a history of trauma did not cause rotator cuff retear after ARCR.
      Table IIThe main outcomes of meta-analysis and subgroup analysis (sociodemographic risk factors)
      Risk factorsNo. of studiesOR or WMDLL 95% CIUL 95% CIP valueI2, %Analysis model
      Age, yr84.38
      WMD.
      2.166.61<.00193IV, random
       Subgroup analysis
      Age (Australia)27.53
      WMD.
      6.328.74<.0010IV, fixed
      Age (Korea)53.98
      WMD.
      1.806.17.00490IV, random
      Age (Korea, EHS)35.38
      WMD.
      4.316.44<.00122IV, fixed
      Sex: male110.83
      OR.
      0.581.20.33070M-H, random
      Sex: female111.05
      OR.
      0.791.41.73055M-H, random
       Sex: female (EHS)100.85
      OR.
      0.711.02.08023M-H, fixed
      Dominant arm70.89
      OR.
      0.681.16.3800M-H, fixed
      Right shoulders21.03
      OR.
      0.811.31.8200M-H, fixed
      Left shoulders20.97
      OR.
      0.771.23.8200M-H, fixed
      Level of sports activity: high20.85
      OR.
      0.421.69.64056M-H, random
      Body mass index40.52
      WMD.
      0.230.82.00662IV, random
       Body mass index (EHS)30.69
      WMD.
      0.530.84<.00122IV, fixed
      Hypertension21.34
      OR.
      0.493.69.57074M-H, random
      Hyperlipidemia41.50
      OR.
      0.992.26.0500M-H, fixed
      Cardiovascular disease21.33
      OR.
      0.772.31.3000M-H, fixed
      Diabetes71.42
      OR.
      1.021.97.0400M-H, fixed
      Smoking81.02
      OR.
      0.751.39.91035M-H, fixed
      Demanding work51.50
      OR.
      0.643.51.35079M-H, random
      Trauma history51.04
      OR.
      0.781.39.78042M-H, fixed
      EHS, eliminate heterogeneous sources; OR, odds ratio; WMD, weighted mean differences; LL, lower limit; CI, confidence interval; UL, upper limit; IV, inverse variance; M-H, Mantel Haenszel test.
      Bold values are statistically significant.
      The Forest map of all risk factors is shown in Supplementary Material S5.
      OR.
      WMD.

       Preoperative clinical evaluation

      Sixteen preoperative clinical objective and subjective evaluation indicators were statistically analyzed (Table III). Bone mineral density was measured by dual-energy X-ray absorptiometry before the operation, and the lowest T score of the proximal femur or lumbar spine was used for the data analysis. Steroid injection refers to treatment with steroid injections before the operation. Meta-analysis showed that if the subscapularis and infraspinatus exhibited fat infiltration, whether the Goutallier grade was ≥2 or <2, these indicators were all risk factors for rotator cuff retear (P < .001). In addition, the research results showed that symptom duration (WMD 4.09, 95% CI 2.34, 5.85; P < .001) and bone mineral density (WMD −0.56, 95% CI −1.04, −0.08; P = .02) were both risk factors for rotator cuff retear. Fatty infiltration of the supraspinatus, forward flexion, external rotation, internal rotation, preoperative frozen shoulder, symptom aggravation, preoperative visual analog scale pain score, preoperative University of California Los Angeles (UCLA) shoulder score, and steroid injection were not risk factors for rotator cuff retear.
      Table IIIThe main outcomes of meta-analysis and subgroup analysis (preoperative clinical evaluation)
      Risk factorsNo. of studiesOR or WMDLL 95% CIUL 95% CIP valueI2, %Analysis model
      Subscapularis fatty infiltration, grade <230.23
      OR.
      0.160.33<.0010M-H, fixed
      Subscapularis fatty infiltration, grade ≥233.37
      OR.
      1.437.93.00578M-H, random
      Subscapularis fatty infiltration, grade ≥2 (EHS)25.25
      OR.
      3.487.93<.0010M-H, fixed
      Supraspinatus fatty infiltration, grade <220.50
      OR.
      0.151.70.27087M-H, random
      Supraspinatus fatty infiltration, grade ≥ 221.88
      OR.
      0.516.96.35090M-H, random
      Infraspinatus fatty infiltration, grade <230.08
      OR.
      0.020.29<.00189M-H, random
      Infraspinatus fatty infiltration, grade ≥ 2311.02
      OR.
      4.3028.24<.00180M-H, random
      Forward flexion, degrees2−3.53
      WMD.
      −9.122.07.2200IV, fixed
      External rotation, degrees20.26
      WMD.
      −7.087.60.94082IV, random
      Internal rotation, degrees2−0.32
      WMD.
      −0.910.26.28045IV, fixed
      Preoperative Frozen shoulder30.99
      OR.
      0.601.62.9600M-H, fixed
      Symptom duration, months74.09
      WMD.
      2.345.85<.00128IV, fixed
      Symptom aggravation, months21.65
      WMD.
      −0.964.27.2200IV, fixed
      Preoperative VAS pain score20.30
      WMD.
      −0.030.63.0700IV, fixed
      Preoperative UCLA score20.35
      WMD.
      −2.272.96.80084IV, random
      Steroid injection31.60
      OR.
      0.347.41.55086M-H, random
      Steroid injection (EHS)20.76
      OR.
      0.411.44.4000M-H, fixed
      Bone mineral density, T score3−0.56
      WMD.
      −1.04−0.08.02084IV, random
      Bone mineral density (EHS)2−0.31
      WMD.
      −0.52−0.10.0030IV, fixed
      EHS, eliminate heterogeneous sources; VAS, visual analog scale; UCLA, University of California Los Angeles shoulder score; OR, odds ratio; WMD, weighted mean differences; LL, lower limit; CI, confidence interval; UL, upper limit; M-H, Mantel Haenszel test; IV, inverse variance.
      Fat infiltration evaluation adopts Goutallier classification.
      Bold values are statistically significant.
      OR.
      WMD.

       Anatomic risk factors

      Eight anatomic factors were analyzed (Table IV). Meta-analysis showed that tear length (WMD 0.83, 95% CI 0.48, 1.18; P < .001), tear width (WMD 0.62, 95% CI 0.26, 0.98; P < .001), tear size area (WMD 3.58, 95% CI 2.31, −5.40; P < .001), amount of retraction (WMD 1.13, 95% CI 1.07, 1.19; P < .001), critical shoulder angle (CSA; WMD 1.66, 95% CI 0.76, 2.57; P < .001), acromiohumeral interval (AI; WMD −1.45, 95% CI −1.59, −1.31; P < .001) and distance from the musculotendinous junction to the glenoid (WMD −4.67, 95% CI −5.05, −4.29; P < .001) were risk factors for rotator cuff retear after ARCR. Among the anatomic factors in this study, only glenoid inclination (WMD 2.39, 95% CI −0.13, 4.92; P = .06) was not a risk factor.
      Table IVThe main outcomes of meta-analysis and subgroup analysis (anatomic and intraoperative factors)
      Risk factorsNo. of studiesOR or WMDLL 95% CIUL 95% CIP valueI2, %Analysis model
      Anatomic factors
       Tear length, cm70.83
      WMD.
      0.481.18<.00192IV, random
       Tear length, cm (EHS)61.03
      WMD.
      0.861.19<.00149IV, fixed
       Tear width, cm50.62
      WMD.
      0.260.98.00791IV, random
       Tear width, cm (EHS)40.77
      WMD.
      0.511.03<.00166IV, random
       Tear size area, cm233.58
      WMD.
      2.315.40<.00182IV, random
       Tear size area, cm2 (EHS)24.78
      WMD.
      4.435.14<.0010IV, fixed
       Amount of retraction, cm31.13
      WMD.
      1.071.19<.0010IV, fixed
       Critical shoulder angle, degree31.66
      WMD.
      0.762.57.0030IV, fixed
       Glenoid inclination, degree22.39
      WMD.
      −0.134.92.0600IV, fixed
       Acromiohumeral interval, mm4−1.45
      WMD.
      −1.59−1.31<.00140IV, fixed
       Distance of musculotendinous junction to glenoid, mm2−4.67
      WMD.
      −5.05−4.29<.0010IV, fixed
      Intraoperative factors
       Operative time, min44.32
      WMD.
      0.408.24.03079IV, random
       Operative time (EHS)36.57
      WMD.
      5.088.07<.0010IV, fixed
       Repair technique, single row71.07
      OR.
      0.841.37.56042M-H, fixed
       Repair technique, double row70.91
      OR.
      0.721.16.45042M-H, fixed
       Distal clavicle resection21.23
      OR.
      0.682.25.4900M-H, fixed
       Biceps lesion/Biceps procedure51.71
      OR.
      1.312.23<.00144M-H, fixed
       Postoperative UCLA score2−1.85
      WMD.
      −3.27−0.43.01068IV, random
      EHS, eliminate heterogeneous sources; UCLA, University of California Los Angeles shoulder score; OR, odds ratio; WMD, weighted mean differences; LL, lower limit; CI, confidence interval; UL, upper limit; IV, inverse variance; M-H, Mantel Haenszel test.
      Bold values are statistically significant.
      OR.
      WMD.

       Intraoperative risk factors

      This study analyzed the effects of 6 surgery-related factors on rotator cuff healing (Table IV). Based on the combined ORs or WMDs, the following risk factors were identified: operative duration (WMD 4.32, 95% CI 0.40, 8.24; P = .003), biceps procedure (OR 1.71, 95% CI 1.31, 2.23; P < .001), and postoperative UCLA score (WMD −1.85, 95% CI −3.27, −0.43; P = .01). In addition, the results of the meta-analysis showed that the repair technique (single row or double row) and distal clavicle resection were not risk factors for rotator cuff retear.

       Publication bias

      Stata 15.1 software was used to perform Egger test on the risk factors for ≥7 included articles and then to evaluate whether there was publication bias. Egger test showed no publication bias for age (P = .81), tear length (P = .11), symptom duration (P = .37), dominant hand (P = .07), diabetes (P = .89), smoking (P = .56), single-row repair (P = .82), or double-row repair (P = .49). Male sex (P = .03) and female sex (P = .03) showed publication bias, and the interpretation of the results of these 2 indicators requires caution. The statistical process and results for publication bias of the above 10 outcome indicators are shown in Supplementary Material S5.

      Discussion

      This study analyzed a total of 45 risk factors in 4 aspects (sociodemographic, preoperative clinical evaluation, and anatomic and intraoperative factors), thereby presenting the most comprehensive data for the analysis of factors related to rotator cuff retear after ARCR. This study used a quantitative, systematic evaluation method for the first time to analyze risk factors of rotator cuff retear after ARCR, which is beneficial for the early identification of patients prone to postoperative retear and to reduce the occurrence of retear after rotator cuff repair by intervening in modifiable factors.

       Sociodemographic risk factors

      This study shows that advanced age (WMD 4.38, 95% CI 2.16, 6.61; P <.001) is a risk factor for rotator cuff retear. Because of the high heterogeneity of combining age data, we conducted a subgroup analysis according to different countries (Australia and South Korea). The results showed that in both the South Korean group and the Australian group, age was a risk factor for retear, which shows that the statistical results are reliable. Animal biomechanics experiments have proven that the maximum load of the tendon in elderly rats at 8 weeks after rotator cuff repair is significantly lower than that in young rats, and pathologic sections have shown that the arrangement of tendon-bone fibroblasts in elderly rats is disordered, the formation of collagen fibrous tissue at the tendon-bone interface is reduced, and the structure of the original tendon is very different, which reduces the stability of tendon healing.
      • Plate J.F.
      • Brown P.J.
      • Walters J.
      • Clark J.A.
      • Smith T.L.
      • Freehill M.T.
      • et al.
      Advanced age diminishes tendon-to-bone healing in a rat model of rotator cuff repair.
      Because the above study is based on the induced tear model, it does not necessarily represent the research results after the natural progression of degenerative RCT repair. However, it also provides a way for us to understand the effect of age on retear after rotator cuff repair. The results of this study are consistent with those reported by Diebold and Cho,
      • Cho N.S.
      • Moon S.C.
      • Jeon J.W.
      • Rhee Y.G.
      The influence of diabetes mellitus on clinical and structural outcomes after arthroscopic rotator cuff repair.
      ,
      • Diebold G.
      • Lam P.
      • Walton J.
      • Murrell G.A.C.
      Relationship between age and rotator cuff retear.
      and, therefore, advanced age can be identified as an independent risk factor for rotator cuff retear after ARCR. Meta-analysis revealed that the higher the BMI (WMD 0.52, 95% CI 0.23, 0.82; P < .001), the more likely the rotator cuff retear is after ARCR. Animal studies have shown that the quality of tendons in obese mouse models is poor and that obesity is related to proinflammatory cytokines and reactive oxygen species.
      • David M.A.
      • Jones K.H.
      • Inzana J.A.
      • Zuscik M.J.
      • Awad H.A.
      • Mooney R.A.
      Tendon repair is compromised in a high fat diet-induced mouse model of obesity and type 2 diabetes.
      ,
      • Longo U.G.
      • Petrillo S.
      • Berton A.
      • Spiezia F.
      • Loppini M.
      • Maffulli N.
      • et al.
      Role of serum fibrinogen levels in patients with rotator cuff tears.
      Therefore, an increase in BMI promotes inflammation and affects tendon healing. Previous studies have also shown that obesity leads to a higher tear rate.
      • Ateschrang A.
      • Eggensperger F.
      • Ahrend M.D.
      • Schröter S.
      • Stöckle U.
      • Kraus T.M.
      Obesity causes poorer clinical results and higher re-tear rates in rotator cuff repair.
      ,
      • Gumina S.
      • Arceri V.
      • Carbone S.
      • Albino P.
      • Passaretti D.
      • Campagna V.
      • et al.
      The association between arterial hypertension and rotator cuff tear: the influence on rotator cuff tear sizes.
      ,
      • Warrender W.J.
      • Brown O.L.
      • Abboud J.A.
      Outcomes of arthroscopic rotator cuff repairs in obese patients.
      The possible reason is that as a result of the accumulation of fatty tissue, obese patients need more strength to lift their shoulders. An increase in BMI may increase the mechanical load on the joints and cause greater pressure on the healing tendons.
      • Kessler K.E.
      • Robbins C.B.
      • Bedi A.
      • Carpenter J.E.
      • Gagnier J.J.
      • Miller B.S.
      Does increased body mass index influence outcomes after rotator cuff repair?.
      Obesity may also promote or involve hypercholesterolemia.
      • Bedi A.
      • Fox A.J.
      • Harris P.E.
      • Deng X.H.
      • Ying L.
      • Warren R.F.
      • et al.
      Diabetes mellitus impairs tendon-bone healing after rotator cuff repair.
      Some studies have shown that hypercholesterolemia is not conducive to rotator cuff tendon healing in rats.
      • Beason D.P.
      • Hsu J.E.
      • Marshall S.M.
      • McDaniel A.L.
      • Temel R.E.
      • Abboud J.A.
      • et al.
      Hypercholesterolemia increases supraspinatus tendon stiffness and elastic modulus across multiple species.
      ,
      • Kim J.M.
      • Kim M.W.
      • Do H.J.
      Influence of hyperlipidemia on the treatment of supraspinatus tendinopathy with or without tear.
      Therefore, the control of BMI and hypercholesterolemia is particularly important for patients with rotator cuff injury. Diabetes (OR 1.42, 95% CI 1.02, 1.97; P = .04) is also a risk factor for postoperative rotator cuff retear. Animal experiments
      • Bedi A.
      • Fox A.J.
      • Harris P.E.
      • Deng X.H.
      • Ying L.
      • Warren R.F.
      • et al.
      Diabetes mellitus impairs tendon-bone healing after rotator cuff repair.
      have shown that compared with nondiabetic rats, diabetic rats have less fibrocartilage and tissue collagen formation at the tendon-bone interface after rotator cuff repair, and the maximum failure load is lower, which indicates that continuous hyperglycemia can inhibit rotator cuff healing after repair. Moreover, clinical studies
      • Chen A.L.
      • Shapiro J.A.
      • Ahn A.K.
      • Zuckerman J.D.
      • Cuomo F.
      Rotator cuff repair in patients with type I diabetes mellitus.
      ,
      • Clement N.D.
      • Hallett A.
      • MacDonald D.
      • Howie C.
      • McBirnie J.
      Does diabetes affect outcome after arthroscopic repair of the rotator cuff?.
      have revealed that diabetic patients exhibit poorer efficacy after rotator cuff repair than nondiabetic patients and present higher failure and infection rates.

       Preoperative clinical evaluation

      The results of the meta-analysis suggest that if the subscapularis and infraspinatus exhibit fat infiltration, regardless of whether the Goutallier stage is ≥2 or <2, these indicators are all risk factors for rotator cuff retear after ARCR (P < .001). Adipose tissue will replace internal muscle fibers, and with the increase in connective tissue content and fibrosis, fatty infiltration will reduce the elasticity and vitality of the rotator cuff tendon tissue and affect the healing of the rotator cuff.
      • Gerber C.
      • Meyer D.C.
      • Frey E.
      • von Rechenberg B.
      • Hoppeler H.
      • Frigg R.
      • et al.
      Neer Award 2007: Reversion of structural muscle changes caused by chronic rotator cuff tears using continuous musculotendinous traction. An experimental study in sheep.
      Gladstone et al
      • Gladstone J.N.
      • Bishop J.Y.
      • Lo I.K.Y.
      • Flatow E.L.
      Fatty infiltration and atrophy of the rotator cuff do not improve after rotator cuff repair and correlate with poor functional outcome.
      believe that in most cases, the greater the degree of muscle fat infiltration, the worse the treatment effect. Muscle atrophy and fat infiltration are independent influencing factors, fat infiltration progresses significantly after rotator cuff repair, and the progression in retear patients is more obvious than that in patients who show healing. Rotator cuff muscle atrophy and fat infiltration, especially that of the infraspinatus muscle, play a key role in determining the functional efficacy of the repair operation. The meta-analysis showed that the longer the duration of symptoms (WMD 4.09, 95% CI 2.34, 5.85; P < .001) and the lower the bone density (WMD −0.56, 95% CI −1.04, −0.08; P = .02 < .05), the more likely rotator cuff retear was after ARCR. Tan et al
      • Tan M.
      • Lam P.H.
      • Le B.T.
      • Murrell G.A.
      Trauma versus no trauma: an analysis of the effect of tear mechanism on tendon healing in 1300 consecutive patients after arthroscopic rotator cuff repair.
      found that patients whose symptoms lasted for a period of 12 months had no increase in the rate of retear 6 months after ARCR. However, patients whose symptoms lasted longer than 24 months had a significantly higher rate of retear at 6 months after ARCR than those whose symptoms lasted less than 24 months (20% vs. 13%, P = .04).
      • Tan M.
      • Lam P.H.
      • Le B.T.
      • Murrell G.A.
      Trauma versus no trauma: an analysis of the effect of tear mechanism on tendon healing in 1300 consecutive patients after arthroscopic rotator cuff repair.
      Tingart et al used computed tomography (CT) scans to observe the bone density of the greater tuberosity of humerus specimens and found that the higher the bone density of the proximal humerus, the greater the force required to pull out the anchor.
      • Tingart M.J.
      • Apreleva M.
      • Lehtinen J.
      • Zurakowski D.
      • Warner J.J.P.
      Anchor design and bone mineral density affect the pull-out strength of suture anchors in rotator cuff repair.
      Pietschmann et al
      • Pietschmann M.F.
      • Fröhlich V.
      • Ficklscherer A.
      • Gülecyüz M.F.
      • Wegener B.
      • Jansson V.
      • et al.
      Suture anchor fixation strength in osteopenic versus non-osteopenic bone for rotator cuff repair.
      evaluated the pull-out strength of metal and absorbable anchors on healthy and osteoporotic cadaveric specimens and concluded that the higher the bone density, the greater the pull-out strength required. Combined with the results of this meta-analysis, there is sufficient evidence to confirm that the lower the bone density is, the easier it is to tear the rotator cuff again after ARCR.

       Anatomic factors

      The statistical results show that tear length (P < .001), tear width (P < .001), tear size area (P < .001), amount of retraction (P < .001), distance of the musculotendinous junction to the glenoid (P < .001), CSA (P < .001), and AI (P < .001) are all risk factors of postoperative rotator cuff retear after ARCR. Previous studies have shown that the greater the preoperative RCT and the longer the postoperative recovery period, the higher the possibility of retear.
      • Ahmad S.
      • Haber M.
      • Bokor D.J.
      The influence of intraoperative factors and postoperative rehabilitation compliance on the integrity of the rotator cuff after arthroscopic repair.
      ,
      • Mall N.A.
      • Tanaka M.J.
      • Choi L.S.
      • Paletta G.A.
      Factors affecting rotator cuff healing.
      ,
      • Tashjian R.Z.
      • Hollins A.M.
      • Kim H.M.
      • Teefey S.A.
      • Middleton W.D.
      • Steger-May K.
      • et al.
      Factors affecting healing rates after arthroscopic double-row rotator cuff repair.
      Gasbarro et al
      • Gasbarro G.
      • Ye J.
      • Newsome H.
      • Jiang K.
      • Wright V.
      • Vyas D.
      • et al.
      Morphologic risk factors in predicting symptomatic structural failure of arthroscopic rotator cuff repairs: tear size, location, and atrophy matter.
      found through a retrospective study that the average supraspinatus tendon tear size in patients with RCT repair failure was significantly larger than that in patients without repair failure. A study involving 1000 cases showed that the size of the preoperative RCT (tear size, tear area, tear layer number) was closely related to the postoperative retear rate.
      • Le B.T.N.
      • Wu X.L.
      • Lam P.H.
      • Murrell G.A.C.
      Factors predicting rotator cuff retears: an analysis of 1000 consecutive rotator cuff repairs.
      Studies have shown that there is a certain correlation between preoperative muscle and tendon retraction and the occurrence of rotator cuff retear, which is the most important pathophysiological result of chronic tendon tearing.
      • Shin Y.K.
      • Ryu K.N.
      • Park J.S.
      • Jin W.
      • Park S.Y.
      • Yoon Y.C.
      Predictive factors of retear in patients with repaired rotator cuff tear on shoulder MRI.
      Muscle retraction is assessed by the position of the musculotendinous junction relative to the scapula, and the gap between the large nodule and the edge of the tendon may be due to tendon shortening or muscle retraction. Rotator cuff retraction can increase the tension of the repair, resulting in poor footprint coverage, and the more severe the rotator cuff retraction is, the longer the patient’s disease course and the worse the tendon quality.
      • Kim Y.
      • Jung K.
      • Kim J.
      • Kim U.
      • Hwang D.
      Factors affecting rotator cuff integrity after arthroscopic repair for medium-sized or larger cuff tears: a retrospective cohort study.
      ,
      • Shin Y.K.
      • Ryu K.N.
      • Park J.S.
      • Jin W.
      • Park S.Y.
      • Yoon Y.C.
      Predictive factors of retear in patients with repaired rotator cuff tear on shoulder MRI.
      ,
      • Tashjian R.Z.
      • Hollins A.M.
      • Kim H.M.
      • Teefey S.A.
      • Middleton W.D.
      • Steger-May K.
      • et al.
      Factors affecting healing rates after arthroscopic double-row rotator cuff repair.
      Studies have shown that the compression force and shear force of the shoulder joint depend on the CSA,
      • Gomide L.C.
      • Carmo T.C.D.
      • Bergo G.H.M.
      • Oliveira G.A.
      • Macedo I.S.
      Relationship between the critical shoulder angle and the development of rotator cuff lesions: a retrospective epidemiological study.
      ,
      • Watanabe A.
      • Ono Q.
      • Nishigami T.
      • Hirooka T.
      • Machida H.
      Association between the critical shoulder angle and rotator cuff tears in Japan.
      and the shear force of the joint increases as the CSA increases, which will cause the shoulder joint to become unstable. Thus, the supraspinatus muscle needs additional force to maintain the stability of the joint. Too high of a CSA will induce the supraspinatus muscle to overload, and this also proves that too high of a CSA will cause the biomechanical properties of the rotator cuff to induce tearing after ARCR.
      • Gerber C.
      • Snedeker J.G.
      • Baumgartner D.
      • Viehöfer A.F.
      Supraspinatus tendon load during abduction is dependent on the size of the critical shoulder angle: a biomechanical analysis.
      The AI refers to the shortest distance between the dense cortical bone under the acromion and the subchondral cortex on the upper part of the humeral head, which is an important factor affecting the function of the rotator cuff. Lee et al's
      • Lee S.
      • Min Y.
      Can inadequate acromiohumeral distance improvement and poor posterior remnant tissue be the predictive factors of re-tear? Preliminary outcomes of arthroscopic superior capsular reconstruction.
      observation of 32 patients after shoulder arthroscopy revealed that the difference between the immediate postoperative AI and the preoperative AI in the retear group was significantly smaller than that in the nonretear group (P = .02). Studies have shown that a shorter AI affects normal glenohumeral mechanics, causing the rotator cuff to tear again after surgery.
      • Chung S.W.
      • Kim J.Y.
      • Kim M.H.
      • Kim S.H.
      • Oh J.H.
      Arthroscopic repair of massive rotator cuff tears: outcome and analysis of factors associated with healing failure or poor postoperative function.

       Intraoperative factors

      In the analysis of the factors related to surgery, we found that operative duration (WMD 4.32, 95% CI 0.40, 8.24), biceps procedure (OR 1.71, 95% CI 1.31, 2.23), and postoperative UCLA score (WMD −1.85, 95% CI −3.27, −0.43) were risk factors for retear after rotator cuff surgery. Studies
      • Diebold G.
      • Lam P.
      • Walton J.
      • Murrell G.A.C.
      Relationship between age and rotator cuff retear.
      ,
      • Lee Y.S.
      • Jeong J.Y.
      • Park C.
      • Kang S.G.
      • Yoo J.C.
      Evaluation of the risk factors for a rotator cuff retear after repair surgery.
      have shown that the longer the operation is, the easier it is to tear the rotator cuff after ARCR, but further research is still needed to determine the related mechanism. Le et al
      • Le B.T.N.
      • Wu X.L.
      • Lam P.H.
      • Murrell G.A.C.
      Factors predicting rotator cuff retears: an analysis of 1000 consecutive rotator cuff repairs.
      believe that a longer operation is related to the length and number of RCTs, especially the size of the tear. Therefore, the long operation may be an indirect cause, and the direct risk factor may be related to the severity of the RCT. Intraoperative surgical manipulation of the biceps brachii will directly affect retearing of the rotator cuff after ARCR. As there are still few studies on this aspect, further study is needed to determine the mechanism of action. Studies have shown that there is a negative correlation between the RCT severity and the UCLA score, which indicates that the smaller the RCT is, the better the treatment effect.
      • Ahmad S.
      • Haber M.
      • Bokor D.J.
      The influence of intraoperative factors and postoperative rehabilitation compliance on the integrity of the rotator cuff after arthroscopic repair.
      Therefore, the postoperative UCLA score and even the preoperative UCLA score can reflect the severity of the RCT, which is conducive to the evaluation of postoperative rotator cuff healing. Many previous studies have shown that the double-row repair technique can achieve stronger fixation and a lower rotator cuff retear rate.
      • Hantes M.E.
      • Ono Y.
      • Raoulis V.A.
      • Doxariotis N.
      • Venouziou A.
      • Zibis A.
      • et al.
      Arthroscopic single-row versus double-row suture bridge technique for rotator cuff tears in patients younger than 55 years: a prospective comparative study.
      ,
      • Huang A.L.
      • Thavorn K.
      • van Katwyk S.
      • MacDonald P.
      • Lapner P.
      Double-row arthroscopic rotator cuff repair is more cost-effective than single-row repair.
      ,
      • Wade R.
      • Salgar S.
      Clinico-radiological evaluation of retear rate in arthroscopic double row versus single row repair technique in full thickness rotator cuff tear.
      The results of this study suggest that the repair technique (single row or double row) is not a risk factor for rotator cuff retear after ARCR. Based on the results of this study and considering the clinical practicability and the economic ability of patients, a single-row suture technique with relatively low cost and technical difficulty can be selected.

       Limitations

      This study has the following limitations. (1) The studies included in this meta-analysis did not consider the size of the RCT, which may have an impact on the results of this report. (2) The cases of retear included in this review were not clearly defined as a natural biological tear or as a retear because of human factors, which are areas that need to be explored in depth in future studies. (3) The included literature is limited, and some risk factors, such as the lateral acromion angle, physical labor, and surgical materials, cannot be combined for analysis. (4) Because the original sample data of the included literature could not be obtained, it was impossible to calculate the accurate average data or interval of some risk factors, such as age, symptom duration, CSA, and AI. Further multicenter and large-sample data need to be explored in the future. (5) The included cases in this study did not clearly distinguish between chronic RCTs or traumatic RCTs, which may affect the credibility of this study.

      Conclusions

      This meta-analysis provides a direction in which orthopedic surgeons and RCT patients can evaluate postoperative rotator cuff retears and presents a theoretical basis for advanced prevention. This study found that sociodemographic factors (age, BMI, diabetes), preoperative clinical evaluation factors (subscapular and subspinatus fatty infiltration, symptom duration, bone mineral density), anatomic factors (tear length, tear width, tear size area, amount of retraction, CSA, AI, distance from the musculotendinous junction to the glenoid), and intraoperative factors (operative duration, biceps procedure, postoperative UCLA score) are risk factors for rotator cuff retear after ARCR. Clinical medical staff can refer to the results of this study to enhance the surgical evaluation of high-risk individuals who are prone to develop retears and to intervene and manage modifiable factors, such as BMI, diabetes mellitus, bone mineral density, and operative duration, that may reduce the rate of postoperative retear after ARCR.

      Disclaimer

      This work was supported by the National Natural Science Foundation of China (No. 81974574, No. 81873314, No. 82004386, No.82004383), the Project of Administration of Traditional Chinese Medicine of Guangdong Province (No.20201129), the Project of Guangdong Provincial Department of Finance (No. [2014]157, No.[2018]8), the Medical Science Research Foundation of Guangdong Province (No.A2020105, No.B2019091), the Science and Technology Planning Project of Guangdong Province (No. 2020A1414050050), the Science and Technology Planning Project of Guangzhou (No. 202102010273) and the Science and Technology Research Project of Guangdong Provincial Hospital of Chinese Medicine (No.YN2019ML08, YN2015MS15).
      The authors, their immediate families, and any research foundations with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article.

      Supplementary Data

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