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Background: In patients with traumatic posterior shoulder instability, little is known about the precise location and size of the reverse Hill-Sachs lesion., Methods: Forty-nine shoulders of 47 patients with traumatic posterior instability were included in this study based on the following inclusion criteria: (1) a primary or recurrent traumatic posterior shoulder dislocation and (2) the initial event being caused by trauma. Patients were excluded if they had (1) no history of trauma, (2) prior shoulder surgery, (3) no computed tomographic (CT) examination, or (4) were seizure cases. Three-dimensional images of the humerus reconstructed from CT images were reviewed using an image analysis software. The location and size of the reverse Hill-Sachs lesion were measured and described on a clock face on the humeral head., Results: The reverse Hill-Sachs lesion was observed in 25 of 49 shoulders (51%). The reverse Hill-Sachs lesions were located between 1:37 and 2:48. The depth of the reverse Hill-Sachs lesion (mean ± standard deviation) was 5.8 ± 2.2 mm. The extent of the reverse Hill-Sachs lesion was 35° ± 12°. The average orientation of the reverse Hill-Sachs lesion, represented by an angle measured from the 12 o'clock position, was 64° ± 12° and pointing toward 2:09 on a clock face. The mean length and width of reverse Hill-Sachs lesions were 9.7 ± 4.7 mm and 11.1 ± 3.6 mm, respectively., Conclusion: The reverse Hill-Sachs lesion was a semicircular compression fracture located on the anteromedial aspect of the humeral head. Compared with shoulders with anterior shoulder instability, the humeral defect was smaller and located more inferiorly in shoulders with posterior instability., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate and compare the pathologies and clinical outcomes of patients with traumatic anterior shoulder instability who underwent arthroscopic stabilization at 40 years or older between shoulders with initial dislocation before age 40 years and at 40 years or after., Methods: Shoulders that underwent arthroscopic stabilization for recurrent traumatic anterior shoulder instability at 40 years or older with a minimum of 2-year follow-up were included. The subjects were divided into 2 groups according to age at initial dislocation after propensity score matching to reduce potential bias: younger than 40 years (group 1) and 40 years or older (group 2). Radiographic findings, pathologies, clinical outcomes, and complications were compared between the groups., Results: Group 1 included 56 shoulders in 56 patients (26 men and 30 women) with a mean age of 51 years (range, 40-77 years). Group 2 included 28 shoulders in 28 patients (13 men and 15 women) with a mean age of 51 years (range, 40-77 years). Glenoid bone loss was greater in group 1 than in group 2 (P = .004). Rotator cuff tears were more frequently observed in group 2 than in group 1 (P < .001). Both groups showed significant improvement in the West Ontario Shoulder Instability Index score (P < .001 for each) and flexion (P < .001 for each). The recurrence rate was 4% in group 1 and 7% in group 2., Conclusions: Rotator cuff tears are significantly more frequent in recurrent shoulder instability patients with initial dislocation at age 40 or older. Arthroscopic stabilization yielded a low recurrence rate and favorable outcomes with a good return-to-sport rate in patients 40 years or older., Level of Evidence: Level III, retrospective comparative prognostic trial., Competing Interests: Disclosures The authors report the following potential conflicts of interest or sources of funding: H.S. is on the speakers bureau of DePuy Synthes, Smith & Nephew, Zimmer Biomet, and Wright Medical, outside the submitted work. K.M. receives grant support from Exactech and Arthrex, outside the submitted work. All other authors (Y.U., N.T., M.T., S.H., K.U., I.K.) declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Full ICMJE author disclosure forms are available for this article online, as supplementary material., (Copyright © 2024 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to investigate the clinical and radiographic outcomes of arthroscopic iliac bone grafting with capsulolabral reconstruction for severe glenoid bone loss with a minimum of 5 years' follow-up., Methods: The inclusion criterion was shoulders that underwent arthroscopic iliac bone grafting for >20%-25% glenoid defect between January 2007 and April 2014, and the exclusion criterion was <5 years' follow-up. Iliac crest bone grafts of approximately 2.0 cm length and 0.8 cm height were arthroscopically fixed to the anterior glenoid using 2 cannulated screws followed by capsulolabral repair. Rowe score, Western Ontario Shoulder Instability Index (WOSI), and passive range of motion were evaluated. Radiographic findings including the Kellgren and Lawrence osteoarthritis grade and graft integration on 3-dimensional computed tomography at the final follow-up were also evaluated., Results: Forty-eight shoulders met the inclusion criteria, and 24 shoulders with ≥5 years' follow-up were included (1 died; 23 were lost follow-up): 22 males, 2 females; a mean age at surgery, 30 years (range, 18-52 years); a mean follow-up of 8 years (range, 5-11 years). The mean preoperative glenoid bone defect was 22% (range, 20%-28%). All shoulders had a Hill-Sachs lesion including 4 on-track lesions. One shoulder experienced traumatic redislocation at 5 years after surgery. The scores significantly improved: Rowe score, 19 ± 8 to 94 ± 8 (P < .001); WOSI, 1547 ± 241 to 439 ± 318 (P < .001). Postoperative flexion showed significant improvement from 158 ± 18 to 169 ± 11 (P = .008), whereas internal rotation deteriorated from T8 ± 3 to T10 ± 3 (P = .005). Graft integration showed remodeling in 54% and excessive absorption in 13%. Osteoarthritis grades progressed significantly (P < .001), but only grade 1 osteoarthritic changes were seen, except for 4 shoulders with grade 2 osteoarthritis., Conclusions: Arthroscopic iliac bone grafting for traumatic anterior shoulder instability with severe glenoid bone loss yielded satisfactory outcomes with mid-term follow-up. Arthritic changes progressed in half of the shoulders; however, most shoulders only demonstrated grade 1 osteoarthritis., Level of Evidence: Level IV, therapeutic case series., (Copyright © 2021 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: To establish an international expert consensus, using the modified Delphi technique, on the evaluation and management of glenohumeral instability with associated bone loss., Methods: A working group of 6 individuals generated a list of statements related to history and physical examination, imaging and specialized diagnostic tests, bone loss quantification and classification, treatment outcomes and complications, and rehabilitation for the management of glenohumeral instability associated with bone loss to form the basis of an initial survey for rating by a group of experts. The expert group (composed of 22 high-volume glenohumeral instability experts) was surveyed on 3 occasions to establish a consensus on the statements. Items with over 70% agreement and less than 10% disagreement achieved consensus., Results: After a total of 3 rounds, 31 statements achieved consensus. Eighty-six percent of the experts agreed that a history of multiple dislocations and failed soft-tissue surgery should raise suspicion about the possibility of an associated bone deficit. Ninety-five percent of the experts agreed that 3-dimensional (3D) computed tomography (CT) is the most accurate diagnostic method to evaluate and quantify bone loss. Eighty-six percent of the experts agreed that any of the available methods to measure glenoid bone deficiency is adequate; however, 91% of the experts thought that an en face view of the glenoid using 3D CT provides the most accurate method. Ninety-five percent of the experts agreed that Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Ninety percent of the experts agreed that in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed and any of the available options is valid. There was no consensus among experts on how Hill-Sachs injuries should be managed or on how postoperative rehabilitation should be carried out., Conclusions: The essential statements on which the experts reached consensus included the following: A history of multiple dislocations and failed soft-tissue surgery should make surgeons consider the possibility of an associated bone deficit. Three-dimensional CT is the most accurate diagnostic method to evaluate and quantify bone loss. Although any of the available methods to measure glenoid bone deficiency is adequate, an en face view of the glenoid using 3D CT provides the most accurate method. Hill-Sachs lesions are poorly quantified and classified by current imaging systems. Finally, in cases with a glenoid bone deficit greater than 20%, glenoid bone graft reconstruction should be performed., Level of Evidence: Level V, consensus statement., (Copyright © 2021 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: Many surgeons prefer bony stabilization including Bristow or Latarjet procedures for shoulder instability in collision athletes, even though several potential complications have been reported. There has been a limited number of studies on the midterm outcomes of arthroscopic soft tissue stabilization for anterior shoulder instability in competitive collision athletes., Purpose: To assess the outcomes of arthroscopic soft tissue stabilization in combination with selective augmentation procedures for collision athletes with traumatic anterior shoulder instability., Study Design: Case series; Level of evidence, 4., Methods: We retrospectively assessed rugby or American football players (<40 years old) who underwent arthroscopic Bankart or bony Bankart repair with selective augmentations (rotator interval closure and/or Hill-Sachs remplissage) for traumatic anterior shoulder instability between January 2012 and March 2017. Shoulders that required other bony procedures were excluded. Recurrence, complications, return to sport, and functional scores (Rowe score and Subjective Shoulder Value sports score) were investigated., Results: This study included 113 shoulders in 100 patients with a mean age of 20 years (range, 15-36 years) at surgery. Rotator interval closure was performed on 36 shoulders in addition to Bankart repair, and rotator interval closure and Hill-Sachs remplissage were performed on 77 shoulders. The mean follow-up period was 44 months (range, 24-72 months). Of the 113 shoulders, 4 (3.5%) experienced postoperative dislocation, but there were no complications. A total of 93 athletes (93%) attained complete or near complete preinjury sports activity levels. The mean Rowe score significantly improved from 36 (range, 10-75) at presurgery to 96 (range, 35-100; P = .003) at postsurgery. The mean Subjective Shoulder Value sports score significantly improved after surgery, from a mean preoperative score of 22 (range, 0-50) to a postoperative score of 92 (range, 64-100; P = .002)., Conclusion: Our treatment strategy, where arthroscopic soft tissue stabilization was combined with selected augmentations, provided good clinical outcomes for competitive collision athletes in terms of low rates of recurrence and complication, a high rate of return to sports, and good shoulder function.

Arthur Sidney Blundell Bankart was a London-based orthopedic surgeon who discovered the essential lesion in recurrent anterior shoulder instability in 1923. He pioneered a technique, the Bankart repair, to re-establish stability to the glenohumeral joint, without sacrificing native joint motion. In this article, the original Bankart repair is compared to the modern arthroscopic Bankart repair, accompanied by a surgical video of Blundell Bankart performing the Bankart repair in 1951, shortly before his death. Bankart's original description included an open repair with a coracoid osteotomy and subscapularis tenotomy and repair. The history of the technique, its utility in present day, and the future of the Bankart repair are discussed., (Copyright © 2020 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate the incidence of axillary nerve palsy after arthroscopic shoulder stabilization and to measure the distance between the nerve and capsule in shoulders with a capsular lesion., Methods: This retrospective study included 2,027 shoulders (1,909 patients; 1,433 male and 476 female patients; mean age, 32 years [age range, 13-81 years]) subjected to arthroscopic soft-tissue stabilization for recurrent shoulder instability from 2005 to 2017. The exclusion criteria were bone grafting or transfer and preoperative axillary nerve symptoms. We retrospectively reviewed patient records and investigated the incidence and clinical features of axillary nerve palsy. We measured the closest distance between the axillary nerve and capsule on preoperative magnetic resonance images., Results: Postoperative axillary nerve palsy occurred in 4 shoulders (0.2% of all arthroscopic stabilizations). Capsular repair was performed in 2 shoulders (1.2% of 160 capsular repairs); humeral avulsion of the glenohumeral ligament (HAGL) repair, 1 shoulder (2% of 47 HAGL repairs); and isolated Bankart repair, 1 shoulder (0.05% of 1,941 Bankart repairs). The closest distance between the nerve and capsule was 3.4 ± 3.2 mm in shoulders with capsular or HAGL lesions and less than 1 mm in the 3 shoulders with palsy. The common symptoms in axillary nerve palsy cases were shoulder discomfort, delayed recovery of range of motion, and deltoid weakness and atrophy. A definitive diagnosis was made with electromyography in all cases. Nerve injury by a suture was confirmed during revision surgery in 3 shoulders subjected to capsular or HAGL repair during the initial operation. The palsy was transient and fully recovered in 1 shoulder with isolated Bankart repair., Conclusions: The incidence of axillary nerve palsy after arthroscopic soft-tissue shoulder stabilization was low but higher in shoulders subjected to capsular or HAGL repair. We should always consider the possibility of axillary nerve palsy in shoulders that require capsular or HAGL repair., Level of Evidence: Level IV, therapeutic case series., (Copyright © 2020 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Purpose: To evaluate osteoconductivity of a poly-L-lactide co-glycolide (PLG)-calcium sulfate (CS)-β-tricalcium phosphate (β-TCP) biocomposite suture anchor after arthroscopic shoulder labral repair., Methods: The subjects of this study were patients who participated in a clinical trial for acquisition of marketing approval of a PLG-CS-β-TCP biocomposite anchor in Japan. They underwent arthroscopic labral repair using the anchor, and computed tomographic (CT) images of the glenoid were obtained 2 years after surgery. Osteoconductivity at the anchor sites was evaluated with the CT images using the established ossification quality score. Shoulder function scores including the Rowe score and Japanese Shoulder Society shoulder instability score were also assessed 2 years after surgery., Results: CT images and functional scores were obtained from 37 patients, comprising 29 men and 8 women with a mean age of 29 years (range, 25-33 years) at surgery. A total of 148 anchors were implanted in the 37 shoulders. Osteoconductivity was seen in 133 of 148 anchor sites (90.0%) 2 years after implantation. No significant differences in osteoconductivity were found by anchor diameter or position. The Rowe score significantly improved from 39.9 points (95% confidence interval [CI], 33.8-45.9 points) preoperatively to 96.6 points (95% CI, 95.1-98.1 points) at 2 years postoperatively (P < .001). The Japanese Shoulder Society shoulder instability score also significantly improved, from 63.1 points (95% CI, 58.4-67.7 points) preoperatively to 96.3 points (95% CI, 94.7-97.8 points) at 2 years postoperatively (P < .001)., Conclusions: Biocomposite suture anchors made of PLG, CS, and β-TCP exhibited some osteoconductivity 2 years after arthroscopic labral repair, as well as good clinical outcomes., Level of Evidence: Level IV, therapeutic case series., (Copyright © 2019 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: Evaluation of range of motion (ROM) restriction before treatment of shoulder disorders is important for predicting the final functional outcomes. The purpose of this study was to investigate correlations of thickness of the coracohumeral ligament (CHL) and ROM restriction in patients with recurrent anterior glenohumeral instability., Methods: Between January 2005 and March 2015, 181 shoulders (137 male and 44 female patients; mean age, 29.3 years) with recurrent anterior glenohumeral instability treated with an arthroscopic Bankart repair were enrolled in this study. We evaluated preoperative ROM, thickness of the CHL, and obliteration of the subcoracoid fat triangle on magnetic resonance arthrography. ROM measurements, including forward flexion (FF), external rotation with the arm at the side (ER), and hand behind the back (HBB), were made in a standing position., Results: There were significant negative correlations between FF and age (P < .001) and between HBB and age (P < .001) but not between ER and age (P = .11). The thickness of the CHL significantly increased with age (P < .001). FF, ER, and HBB were significantly restricted in patients with obliteration compared with those without obliteration (P < .001, P = .004, P < .001, respectively)., Conclusions: Obliteration of the subcoracoid fat triangle and the thickness of the CHL positively correlated with ROM restrictions, and these changes were greater with age in patients with recurrent anterior glenohumeral instability., (Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.)

Background: Arthroscopic osseous Bankart repair for shoulders with chronic recurrent anterior instability has been reported as an effective procedure with promising short-term outcomes. However, to date, we know of no report describing longer-term outcomes and glenoid morphologic change. The purpose of the present study was to report intermediate to long-term outcomes and glenoid morphologic change after arthroscopic osseous Bankart repair in patients with substantial glenoid bone loss., Methods: A consecutive series of eighty-five patients with traumatic anterior glenohumeral instability associated with a chronic osseous Bankart lesion underwent arthroscopic repair from January 2005 through December 2006. Forty-six patients with bone loss of >15% of the inferior glenoid diameter relative to the assumed inferior circle regardless of the fragment size were selected as candidates for this study. Thirty-eight patients (83%), including thirty-four male and four female patients, with a mean age of 23.4 years (range, fifteen to thirty-six years) at the time of surgery, were available for final follow-up at a mean of 6.2 years (range, 5.0 to 8.1 years) after surgery., Results: One patient had a redislocation during a traffic accident five months after surgery before obtaining an osseous union. The mean Rowe score and the mean Western Ontario Shoulder Instability Index improved significantly from 30.7 points preoperatively to 95.4 points postoperatively and from 26.5% to 81.5%, respectively. Although the mean preoperative fragment size was measured as only 4.7%, the mean glenoid bone loss improved from 20.4% preoperatively to -1.1% postoperatively., Conclusions: Arthroscopic osseous Bankart repair is an effective primary treatment for shoulders with substantial glenoid bone loss as it provides successful outcomes without recurrence of instability once osseous union is obtained. Glenoid morphology can be normalized during the intermediate to long-term postoperative period, even in shoulders with a smaller fragment., (Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.)

Purpose: The purpose of this study was to clarify the effectiveness of an arthroscopic procedure for restoration of anterior transverse sliding (RATS) mechanism of the subscapularis tendon in patients with loss of external rotation after surgical stabilization of anterior glenohumeral instability., Methods: Seven patients who underwent an arthroscopic RATS procedure for loss of external rotation after surgical stabilization of anterior glenohumeral instability were retrospectively reviewed. There were 4 male and 3 female patients with a mean age of 30.7 years. The original procedure was arthroscopic Bankart repair and rotator interval closure in 5 patients, open Bankart repair in 1, and an open Bristow procedure in 1. The arthroscopic RATS procedure was performed as follows: (1) removal of the fibrous tissue in the rotator interval; (2) release of the subscapularis tendon from the glenoid neck; and (3) incision of the superior part of the inferior glenohumeral ligament until a sufficient external rotation angle was obtained without causing anterior instability. We evaluated the mean forward flexion and external and internal rotation angles, Constant score, and University of California, Los Angeles score before the arthroscopic RATS procedure and at final follow-up (mean, 24 months)., Results: The mean forward flexion and external and internal rotation angles improved from 162.1° ± 9.5° to 171.4° ± 3.8° (P < .05), from 2.9° ± 4.9° to 47.9° ± 9.1° (P < .005), and from T10 to T8 (P < .05), respectively. The mean Constant and University of California, Los Angeles scores improved from 81.0 ± 13.6 points to 95.1 ± 4.0 points and from 24.0 ± 3.7 points to 33.9 ± 2.0 points, respectively (P < .005)., Conclusions: The arthroscopic RATS mechanism procedure is a useful treatment option with minimum morbidity in patients with loss of external rotation after surgical stabilization of traumatic anterior glenohumeral instability., Level of Evidence: Level IV, therapeutic case series., (Copyright © 2012 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: The Western Ontario Shoulder Instability Index (WOSI) questionnaire is a disease-specific self-evaluated measurement tool used for patients with shoulder instability. The purpose of this study was to evaluate the reliability and validity of the WOSI Japanese version for the Japanese population., Methods: The WOSI Japanese version was prepared by use of several steps including translation, back translation, and verification by the author and owner of the WOSI. Reliability (internal consistency and reproducibility) and validity were then tested for 85 patients with shoulder instability. All patients completed the WOSI Japanese version, Quick DASH, and SF-36, and underwent assessment of the Rowe rating scale for the purpose of internal consistency and validity. Fifty-nine of the patients repeated the WOSI 2 weeks after the first examination for assessment of test-retest reproducibility., Results: Both internal consistency (0.84 for Cronbach's alpha) and reproducibility (Pearson's r = 0.91, intraclass correlation coefficient = 0.91) indicated the reliability of the WOSI Japanese questionnaire was good. Comparison with the Rowe rating scale (p < 0.001) also showed validity was good. The correlation coefficient between the WOSI Japanese version and the Quick DASH (Pearson's r = 0.62) was higher than that between the WOSI Japanese version and the SF-36 (Pearson's r = 0.10-0.36 for subscales)., Conclusion: The WOSI Japanese questionnaire is a reliable self-assessment tool that is comparable with the original English version. We therefore recommend use of the WOSI Japanese version when evaluating patients with shoulder instability in the Japanese population.

Background: A chronic osseous Bankart lesion has traditionally been treated with soft-tissue repair and/or open bone-grafting for a large glenoid defect. We developed an arthroscopic method of osseous reconstruction of the glenoid without bone-grafting. The purpose of this study was to evaluate the postoperative outcomes of our technique for chronic recurrent traumatic anterior glenohumeral instability., Methods: A consecutive series of forty-two shoulders in forty-one patients with chronic recurrent traumatic glenohumeral instability underwent an arthroscopic osseous Bankart repair. All shoulders were evaluated preoperatively with three-dimensionally reconstructed computed tomography, which confirmed an osseous fragment at the anteroinferior portion of the glenoid. The average bone loss in the glenoid was 24.8% (range, 11.4% to 38.6%), and the average fragment size was 9.2% (range, 2.1% to 20.9%) of the glenoid fossa. In all shoulders, a displaced osseous fragment, firmly attached to the labroligamentous complex, was separated from the glenoid neck before reduction and fixation in the optimal position with use of suture anchors. All patients were assessed with use of the scoring systems of Rowe et al. and the University of California at Los Angeles preoperatively and at the final evaluation., Results: The mean duration of follow-up was thirty-four months. At that time, thirty-nine of the forty-two shoulders were rated as having a good or excellent result. The mean Rowe score improved from 33.6 points preoperatively to 94.3 points postoperatively (p < 0.01). The mean score on the University of California at Los Angeles system improved from 20.5 points preoperatively to 33.6 points at the final evaluation (p < 0.01). The average passive external rotation was 75 degrees with the arm at the side and 93 degrees with the arm at 90 degrees of abduction. Two patients had a reinjury. Eventually, thirty-five of thirty-seven patients who were active participants in sports returned to the sport they had played before the injury., Conclusions: Arthroscopic osseous Bankart repair with use of suture anchors yields a successful outcome even in shoulders with a chronic large glenoid defect.

Background: A chronic osseous Bankart lesion has traditionally been treated with soft-tissue repair and/or open bone-grafting for a large glenoid defect. We developed an arthroscopic method of osseous reconstruction of the glenoid without bone-grafting. The purpose of this study was to evaluate the postoperative outcomes of our technique for chronic recurrent traumatic anterior glenohumeral instability., Methods: A consecutive series of forty-two shoulders in forty-one patients with chronic recurrent traumatic glenohumeral instability underwent an arthroscopic osseous Bankart repair. All shoulders were evaluated preoperatively with three-dimensionally reconstructed computed tomography, which confirmed an osseous fragment at the anteroinferior portion of the glenoid. The average bone loss in the glenoid was 24.8% (range, 11.4% to 38.6%), and the average fragment size was 9.2% (range, 2.1% to 20.9%) of the glenoid fossa. In all shoulders, a displaced osseous fragment, firmly attached to the labroligamentous complex, was separated from the glenoid neck before reduction and fixation in the optimal position with use of suture anchors. All patients were assessed with use of the scoring systems of Rowe et al. and the University of California at Los Angeles preoperatively and at the final evaluation., Results: The mean duration of follow-up was thirty-four months. At that time, thirty-nine of the forty-two shoulders were rated as having a good or excellent result. The mean Rowe score improved from 33.6 points preoperatively to 94.3 points postoperatively (p < 0.01). The mean score on the University of California at Los Angeles system improved from 20.5 points preoperatively to 33.6 points at the final evaluation (p < 0.01). The average passive external rotation was 75 degrees with the arm at the side and 93 degrees with the arm at 90 degrees of abduction. Two patients had a reinjury. Eventually, thirty-five of thirty-seven patients who were active participants in sports returned to the sport they had played before the injury., Conclusions: Arthroscopic osseous Bankart repair with use of suture anchors yields a successful outcome even in shoulders with a chronic large glenoid defect.

Background: Knowledge regarding the morphology of the glenoid rim is important when patients with recurrent anterior glenohumeral instability are assessed. Ordinary imaging techniques are not always sensitive enough to demonstrate the morphology of the glenoid rim accurately. We developed a method of three-dimensionally reconstructed computed tomography with elimination of the humeral head to evaluate glenoid morphology. The purpose of the present study was to quantify glenoid osseous defects and to define their characteristics in patients with recurrent anterior instability., Methods: The morphology of the glenoid rim in 100 consecutive shoulders with recurrent unilateral anterior glenohumeral instability was evaluated on three-dimensionally reconstructed computed tomography images with the humeral head eliminated. The configuration of the glenoid rim was evaluated on both en face and oblique views. Concurrently, we also investigated seventy-five normal glenoids, including both glenoids in ten normal volunteers. Shoulders without an osseous fragment at the anteroinferior portion of the glenoid were compared with the contralateral shoulder in the same patient to determine if the glenoid morphology was normal. In shoulders with an osseous fragment, the fragment was evaluated quantitatively and its size was classified as large (>20% of the glenoid fossa), medium (5% to 20%), or small (<5%). Finally, all 100 shoulders were evaluated arthroscopically to confirm the presence of the lesion at the glenoid rim that had been identified with three-dimensionally reconstructed computed tomography., Results: Investigation of the normal glenoids revealed no side-to-side differences. Investigation of the affected glenoids revealed an abnormal configuration in ninety shoulders. Fifty glenoids had an osseous fragment. One fragment was large (26.9% of the glenoid fossa), twenty-seven fragments were medium (10.6% of the glenoid fossa, on the average), and twenty-two were small (2.9% of the glenoid fossa, on the average). In the forty shoulders without an osseous fragment, the anteroinferior portion of the glenoid appeared straight on the en face view and it appeared obtuse or slightly rounded, compared with the normally sharp contour of the normal glenoid rim, on the oblique view, suggesting erosion or a mild compression fracture at this site. Arthroscopic investigation revealed a Bankart lesion in ninety-seven of the 100 shoulders and an osseous fragment in forty-five of the fifty shoulders in which an osseous Bankart lesion had been identified with the three-dimensionally reconstructed computed tomography. In the shoulders with distinctly abnormal morphology on three-dimensionally reconstructed computed tomography, the arthroscopic appearance of the anteroinferior portion of the glenoid rim was compatible with the appearance demonstrated by the three-dimensionally reconstructed computed tomography., Conclusions: We introduced a method to evaluate the morphology of the glenoid rim and to quantify the osseous defect in a simple and practical manner with three-dimensionally reconstructed computed tomography with elimination of the humeral head. Fifty percent of the shoulders with recurrent anterior glenohumeral instability had an osseous Bankart lesion; 40% did not have an osseous fragment but demonstrated loss of the normal circular configuration on the en face view and an obtuse contour on the oblique view, suggesting erosion or compression of the glenoid rim.