The recently published article by Cho et al.1Cho N.S. Lubis A.M.T. Ha J.H. Rhee Y.G. Clinical results of arthroscopic Bankart repair with knot-tying and knotless suture anchors.Arthroscopy. 2006; 22: 1276-1282Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar is a retrospective evaluation of 123 shoulders in 117 patients who underwent arthroscopic Bankart repair using either knot-tying suture anchors or knotless suture anchors. Of the patients, 41 (30% of the cohort) were retrospectively excluded from the study. The authors report on the 82 remaining patients, consisting of 61 patients in the knot-tying group and 21 in the knotless group. The redislocation rate in the knot-tying group was superior to that in the knotless group. There are numerous flaws in this study that raise significant questions as to the validity of the authors’ conclusions.Of particular concern is that the surgical technique used for the Knotless Anchor insertion in this study is different from that described by the manufacturer (DePuy Mitek, Raynham, MA). The authors report that a “bone punch” was used to create a “punch hole.” The Knotless Anchor system does not use a bone punch but rather a drill bit of a specific diameter. Use of the Knotless Anchor with an inappropriate drill hole size is an off-label use of the anchor that could affect its performance.The retrospective, disproportionate exclusions from the 2 groups in this study raise significant concern. It would be expected that the groups would have roughly an equal number of cases because the anchor type was randomly selected. Therefore most, if not all, of the 41 shoulders excluded from the study were from the knotless group, leaving a disproportionately lower number of patients in this group.Inclusion and exclusion criteria were established retrospectively, and the rationale for the criteria is not clearly provided. Patients with SLAP tears, rotator cuff fibrillation, bony Bankart lesion, or hyperlaxity were excluded. SLAP tear type or frequency is not reported. The authors do not report whether patients with type I SLAP tears or only those requiring repair were excluded. Were patients with minimal rotator cuff fibrillation excluded? The rationale for exclusion and the number excluded in each group are not reported. Patients with “hyperlaxity” were excluded based on a positive sulcus sign. This is a subjective sign. The authors do explain how they standardized this determination. They fail to report whether any patient underwent additional procedures or whether patients were excluded if an interval closure, posterior labral repair, or thermal capsulorrhaphy was performed. First-time dislocators were included in the study, but it is not reported how many were in each group. The authors do not report whether all patients had an initial traumatic event. The number of preoperative subluxations or dislocations in each group is not reported. The authors report that all patients had a Bankart lesion, but they excluded patients with an anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion. They do not provide a rationale for excluding patients with an ALPSA lesion or indicate how many patients were excluded from each group. The age distribution in each group is not provided, particularly how many patients were aged 22 years or less. All of these factors can significantly influence redislocation rates, particularly if these factors are disproportionately represented in either group.The authors state that they “randomly decided in each case whether to use knot-tying suture anchors or knotless suture anchors” during the operation. They do not explain the randomization process. Because anchor selection was determined intraoperatively, there is concern that the anchor selection process was not entirely random. The choice of anchor could have been influenced by the intraoperative findings.The number of patients lost to follow-up is not reported. Are we to assume that they had 100% follow-up with their initial group of 123 patients? The authors report that “all patients were followed for at least 24 months”; however, they do not indicate when the postoperative evaluations were performed and who performed the evaluations. They do not report whether all patients were re-examined after 24 months or whether this information was obtained by a chart review or phone interview.The authors do not report whether any imaging study was performed preoperatively to evaluate for anterior glenoid deficiency or the presence of a large Hill-Sachs lesion. It is possible that the incidence of these important lesions was not evenly matched in the 2 groups. The authors do not report whether postoperative radiographs were obtained to document appropriate placement of the metallic anchors used in this study.The authors claim several unsupported conclusions. I would challenge the authors to explain how their data support the following reported conclusions:•“The barbs of the knotless anchor are therefore not necessarily locked within the bone, and subsequent cyclic loading of the knotless anchor may result in gap formation and loose fixation.”•“The significantly higher redislocation rate in the knotless group can be attributed to the challenge associated with determining the depth of the anchor.”•“Premature anchor disintegration” is mentioned as another potential cause for failure of the knotless anchor. The anchors used in this study were nonabsorbable metallic anchors!•The authors need to explain why the results in their knotless anchor group are inferior to those in other previously reported series. Hayashida et al.2Hayashida K. Yoneda M. Mizuno N. Fukushima S. Nakagawa S. Arthroscopic Bankart repair with knotless suture anchor for traumatic anterior shoulder instability: Results of short-term follow-up.Arthroscopy. 2006; 22: 620-626Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar reported on 47 patients with a 6.4% recurrence rate and Garofalo et al.3Garofalo R. Mocci A. Moretti B. et al.Arthroscopic treatment of anterior shoulder instability using knotless suture anchors.Arthroscopy. 2005; 21: 1283-1289Abstract Full Text Full Text PDF PubMed Scopus (56) Google Scholar reported on 20 patients with a 5% recurrence rate by use of knotless suture anchors. My series of 72 patients with a 6.9% recurrence rate was just published in the April 2007 issue of Arthroscopy.4Thal R. Nofziger M. Bridges M. Kim J.J. Arthroscopic Bankart repair using Knotless or BioKnotless suture anchors: 2- to 7-year results.Arthroscopy. 2007; 23: 367-375Abstract Full Text Full Text PDF PubMed Scopus (61) Google ScholarObviously, there are numerous significant flaws in this article that can explain why the authors report an apparent difference in recurrence rate. It is surprising that this poorly designed, unscientific paper was accepted for publication without significant modifications. The conclusions are not scientifically supported and are not consistent with other reported clinical and biomechanical studies. The recently published article by Cho et al.1Cho N.S. Lubis A.M.T. Ha J.H. Rhee Y.G. Clinical results of arthroscopic Bankart repair with knot-tying and knotless suture anchors.Arthroscopy. 2006; 22: 1276-1282Abstract Full Text Full Text PDF PubMed Scopus (53) Google Scholar is a retrospective evaluation of 123 shoulders in 117 patients who underwent arthroscopic Bankart repair using either knot-tying suture anchors or knotless suture anchors. Of the patients, 41 (30% of the cohort) were retrospectively excluded from the study. The authors report on the 82 remaining patients, consisting of 61 patients in the knot-tying group and 21 in the knotless group. The redislocation rate in the knot-tying group was superior to that in the knotless group. There are numerous flaws in this study that raise significant questions as to the validity of the authors’ conclusions. Of particular concern is that the surgical technique used for the Knotless Anchor insertion in this study is different from that described by the manufacturer (DePuy Mitek, Raynham, MA). The authors report that a “bone punch” was used to create a “punch hole.” The Knotless Anchor system does not use a bone punch but rather a drill bit of a specific diameter. Use of the Knotless Anchor with an inappropriate drill hole size is an off-label use of the anchor that could affect its performance. The retrospective, disproportionate exclusions from the 2 groups in this study raise significant concern. It would be expected that the groups would have roughly an equal number of cases because the anchor type was randomly selected. Therefore most, if not all, of the 41 shoulders excluded from the study were from the knotless group, leaving a disproportionately lower number of patients in this group. Inclusion and exclusion criteria were established retrospectively, and the rationale for the criteria is not clearly provided. Patients with SLAP tears, rotator cuff fibrillation, bony Bankart lesion, or hyperlaxity were excluded. SLAP tear type or frequency is not reported. The authors do not report whether patients with type I SLAP tears or only those requiring repair were excluded. Were patients with minimal rotator cuff fibrillation excluded? The rationale for exclusion and the number excluded in each group are not reported. Patients with “hyperlaxity” were excluded based on a positive sulcus sign. This is a subjective sign. The authors do explain how they standardized this determination. They fail to report whether any patient underwent additional procedures or whether patients were excluded if an interval closure, posterior labral repair, or thermal capsulorrhaphy was performed. First-time dislocators were included in the study, but it is not reported how many were in each group. The authors do not report whether all patients had an initial traumatic event. The number of preoperative subluxations or dislocations in each group is not reported. The authors report that all patients had a Bankart lesion, but they excluded patients with an anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion. They do not provide a rationale for excluding patients with an ALPSA lesion or indicate how many patients were excluded from each group. The age distribution in each group is not provided, particularly how many patients were aged 22 years or less. All of these factors can significantly influence redislocation rates, particularly if these factors are disproportionately represented in either group. The authors state that they “randomly decided in each case whether to use knot-tying suture anchors or knotless suture anchors” during the operation. They do not explain the randomization process. Because anchor selection was determined intraoperatively, there is concern that the anchor selection process was not entirely random. The choice of anchor could have been influenced by the intraoperative findings. The number of patients lost to follow-up is not reported. Are we to assume that they had 100% follow-up with their initial group of 123 patients? The authors report that “all patients were followed for at least 24 months”; however, they do not indicate when the postoperative evaluations were performed and who performed the evaluations. They do not report whether all patients were re-examined after 24 months or whether this information was obtained by a chart review or phone interview. The authors do not report whether any imaging study was performed preoperatively to evaluate for anterior glenoid deficiency or the presence of a large Hill-Sachs lesion. It is possible that the incidence of these important lesions was not evenly matched in the 2 groups. The authors do not report whether postoperative radiographs were obtained to document appropriate placement of the metallic anchors used in this study. The authors claim several unsupported conclusions. I would challenge the authors to explain how their data support the following reported conclusions:•“The barbs of the knotless anchor are therefore not necessarily locked within the bone, and subsequent cyclic loading of the knotless anchor may result in gap formation and loose fixation.”•“The significantly higher redislocation rate in the knotless group can be attributed to the challenge associated with determining the depth of the anchor.”•“Premature anchor disintegration” is mentioned as another potential cause for failure of the knotless anchor. The anchors used in this study were nonabsorbable metallic anchors!•The authors need to explain why the results in their knotless anchor group are inferior to those in other previously reported series. Hayashida et al.2Hayashida K. Yoneda M. Mizuno N. Fukushima S. Nakagawa S. Arthroscopic Bankart repair with knotless suture anchor for traumatic anterior shoulder instability: Results of short-term follow-up.Arthroscopy. 2006; 22: 620-626Abstract Full Text Full Text PDF PubMed Scopus (49) Google Scholar reported on 47 patients with a 6.4% recurrence rate and Garofalo et al.3Garofalo R. Mocci A. Moretti B. et al.Arthroscopic treatment of anterior shoulder instability using knotless suture anchors.Arthroscopy. 2005; 21: 1283-1289Abstract Full Text Full Text PDF PubMed Scopus (56) Google Scholar reported on 20 patients with a 5% recurrence rate by use of knotless suture anchors. My series of 72 patients with a 6.9% recurrence rate was just published in the April 2007 issue of Arthroscopy.4Thal R. Nofziger M. Bridges M. Kim J.J. Arthroscopic Bankart repair using Knotless or BioKnotless suture anchors: 2- to 7-year results.Arthroscopy. 2007; 23: 367-375Abstract Full Text Full Text PDF PubMed Scopus (61) Google Scholar Obviously, there are numerous significant flaws in this article that can explain why the authors report an apparent difference in recurrence rate. It is surprising that this poorly designed, unscientific paper was accepted for publication without significant modifications. The conclusions are not scientifically supported and are not consistent with other reported clinical and biomechanical studies. Clinical Results of Arthroscopic Bankart Repair With Knot-Tying and Knotless Suture AnchorsArthroscopyVol. 22Issue 12PreviewPurpose: To compare the results of arthroscopic Bankart repair completed with knot-tying with results of the procedure performed with knotless suture anchors. Methods: We evaluated 82 patients who underwent arthroscopic Bankart repair. A total of 61 patients were treated with knot-tying suture anchors, and 21 patients were treated with knotless suture anchors during the same period. In all, 75 male and 7 female patients were studied. Mean patient age at the time of operation was 24 years (range, 16 to 42 years), and the mean follow-up period had a duration of 29 months (range, 24 to 41 months’ duration). Full-Text PDF Authors’ ReplyArthroscopyVol. 23Issue 5PreviewWe thank Dr. Thal for his sincere and valuable comments about our article. We are pleased to offer our explanation to clarify the queries raised. The surgical technique used for the knotless anchor insertion in our study is not different from that described by the manufacturer, DePuy Mitek.1 We described that a “bone punch” was used to create a “punch hole” only when knot-tying suture anchors were used. When knotless suture anchors were used, drill holes were created by use of the Mitek drill guide and the Mitek 2.9-mm arthroscopic super drill.
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Raymond Thal (2007) studied this question.
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