Minimal but potentially clinically relevant anteroinferior position of the humeral head following traumatic anterior shoulder dislocations: A 3D-CT analysis.

In unstable shoulders, excessive anteroinferior position of the humeral head relative to the glenoid can lead to a dislocation. Measuring humeral head position could therefore be valuable in quantifying shoulder laxity. The aim of this study was to measure (1) position of the humeral head relative to the glenoid and (2) joint space thickness during passive motion in unstable shoulders caused by traumatic anterior dislocations and in contralateral uninjured shoulders. A prospective cross-sectional CT-study was performed in patients with unilateral anterior shoulder instability. Patients underwent CT scanning of both injured and uninjured side in supine position (0° abduction and 0° external rotation) and in 60°, 90°, and 120° of abduction with 90° of external rotation without an external load. Subsequently, 3D virtual models were created of the humerus and the scapula to create a glenoid coordinate system to identify poster-anterior, inferior-superior, and lateral-medial position of the humeral head relative to the glenoid. Joint space thickness was defined as the average distance between the subchondral bone surfaces of the humeral head and glenoid. Fifteen consecutive patients were included. In supine position, the humeral head was positioned more anteriorly (p = 0.004), inferiorly (p = 0.019), and laterally (p = 0.021) in the injured compared to the uninjured shoulder. No differences were observed in any of the other positions. A joint-space thickness map, showing the bone-to-bone distances, identified the Hill-Sachs lesion footprint on the glenoid surface in external rotation and abduction, but no differences on average joint space thickness were observed in any position.

Statistical shape models that predict native glenoid width based on glenoid height are inaccurate in their current form: A cross-sectional study.

BACKGROUND: The extent of measurement errors of statistical shape models that predict native glenoid width based on glenoid height to subsequently determine the amount of anterior glenoid bone loss is unclear. Therefore, the aim of this study was to (1) create a statistical shape model based on glenoid height and width measured on 3D-CT and determine the accuracy through measurement errors and (2) determine measurement errors of existing 3D-CT statistical shape models. MATERIALS AND METHODS: A retrospective cross-sectional study included all consecutive patients that underwent CT-imaging before undergoing primary surgical treatment of traumatic anterior shoulder dislocation between 2007 and 2022 at the Tohoku University Hospital and affiliated hospitals. Patients were included when instability was unilateral and CT scans of both the injured and contralateral uninjured shoulder were available. 3D segmentations were created and glenoid height and width of the injured and contralateral uninjured side (gold standard) were measured. Accuracy was determined through measurement errors, which were defined as a percentage error deviation from native glenoid width (contralateral uninjured glenoid), calculated as measurement error = ((estimated glenoid width with a statistical shape model - native glenoid width) / native glenoid width) x 100%. A linear regression analysis was performed to create a statistical shape model based on glenoid height according to the formula native glenoid width = a * glenoid height + b. RESULTS: The diagnosis and procedure codes identified 105 patients, of which 69 (66%) were eligible for inclusion. Glenoid height demonstrated a very strong correlation (r= 0.80) with native glenoid width. The linear regression formula based on this cohort was native glenoid width = 0.75 * glenoid height - 0.61 and demonstrated an absolute average measurement error of 5 ± 4%. The formulas by Giles et al, Chen et al and Rayes et al demonstrated absolute average measurement errors of 10 ± 7%, 6 ± 5% and 9 ± 6%, respectively CONCLUSION: Statistical shape models that estimate native glenoid width based on glenoid height demonstrate unacceptable measurement errors, despite a high correlation. Therefore, great caution is advised when using these models to determine glenoid bone loss percentage. To minimize errors caused by morphological differences, preference goes to methods that use the contralateral side as reference.

High variability in what is considered important to report following instability surgery: a Delphi study among Dutch shoulder specialists.

Background: Standardized reporting leads to high-quality data and can reduce administration time. The aim of this study was to (1) get an insight into the variability of what is considered important to report in the surgical report following shoulder instability surgery and (2) determine which elements should be included in the surgical report following shoulder instability surgery according to Dutch surgeons using a Delphi method. Methods: Dutch orthopedic shoulder surgeons were included in a panel for a Delphi study consisting of 3 rounds. Importance of the elements was rated on a 9-point Likert scale. High variability was defined as an element that received at least 1 score between 1 and 3 and 1 score between 7 and 9 in round 3. Consensus was defined as ≥80% of the panel giving a score of 7 or more. Results: Seventeen shoulder specialists completed all 3 rounds and identified a total of 82 elements for the arthroscopic Bankart repair and 60 for the open Latarjet. High variability was observed in 57 (70%) and 52 (87%) of the elements, respectively. After round 3, the panel reached consensus on 27 and 11 elements that should be mentioned in the surgical report following arthroscopic Bankart repair and open Latarjet. Conclusion: There is high variability in what shoulder specialists regard essential to report. Consensus was reached on 27 and 11 elements to be reported following arthroscopic Bankart repair and open Latarjet, respectively. Future studies on an international scale can further improve data collection and communication between specialists.

A modified Delphi study to identify which items should be evaluated in shoulder instability research: a first step in developing a core outcome set.

Background: The aim of this study was to identify items that healthcare providers and/or patients consider important to include in a questionnaire for clinical trials and cohort studies in shoulder instability research. This could serve as a basis to develop a core outcome set for shoulder instability research. Methods: Healthcare providers and patients were included in a panel for a modified Delphi consensus study. The study consisted of three rounds, comprising (1) identifying items, (2) rating the importance of the items, and (3) rating the importance again after seeing a summary of the results of round two. Importance was rated on a 9-point Likert scale. Consensus was defined as ≥ 80% of the panel giving a score of 7 or higher. Results: In total, 44 healthcare providers and 30 patients completed all three rounds. Round one identified 54 items. After round three, the panel reached a consensus on 11 items that should be included in a questionnaire, comprising re-dislocation (99%), instable feeling of the shoulder (96%), limitations during sport (93%), patient satisfaction with the shoulder (93%), fear/anxiety for re-dislocation (91%), range of motion (88%), return to old level of functioning (85%), performing daily activities (85%), return to sport (82%), return to work (82%), and trusting the shoulder (81%). Conclusion: Healthcare providers and patients reached a consensus on 11 items that should be included in a questionnaire for shoulder instability research. These items can facilitate design and development of future clinical trials and form the basis for the development of a core outcome set.

Changes in Scapular Function, Shoulder Strength, and Range of Motion Occur After Latarjet Procedure.

Purpose: To evaluate the current literature on the effects of anatomic changes caused by the Latarjet procedure and to identify areas for future research. Methods: English-language studies that addressed the consequences of anatomic alterations after the open Latarjet procedure were included. Articles written in languages other than English, reviews, and case reports were excluded. Titles and abstracts were screened by 2 authors. Studies that met the inclusion criteria were screened by the same authors. The following data were extracted from the included studies: authors, year of publication, journal, country of origin, aims or purpose, study population and sample size, methods, procedure, intervention type, and key findings that relate to the scoping review questions. Results: Twenty-two studies were included for analysis, yielding the following findings: First, the Latarjet procedure may change the position of the scapula owing to pectoralis minor tenotomy and/or transfer of the conjoint tendon. Second, dissection of the coracoacromial ligament may result in increased superior translation of the humeral head. The impact of this increased translation on patients' function remains unclear. Third, the subscapularis split shows, overall, better internal rotation strength compared with subscapularis tenotomy. Fourth, passive external rotation may be limited after capsular repair. Fifth, despite the movement of the conjoint tendon, elbow function seems unchanged. Finally, the musculocutaneous nerve is lengthened with a changed penetration angle into the coracobrachialis muscle, but the clinical impact seems limited. Conclusions: The Latarjet procedure leads to anatomic and biomechanical changes in the shoulder. Areas of future research may include better documentation of scapular movement (bilateral, as well as preoperative and postoperative) and elbow function, the effect of (degenerative) rotator cuff ruptures after the Latarjet procedure on shoulder function, and the impact of capsular closure and its contribution to the development of glenohumeral osteoarthritis. Clinical Relevance: This comprehensive overview of anatomic changes after the Latarjet procedure, with its effects on shoulder and elbow function, showed gaps in the current literature. Orthopaedic shoulder surgeons and physical therapists could use our findings when providing patient information and performing future clinical research.

Surgical Intervention Following a First Traumatic Anterior Shoulder Dislocation Is Worthy of Consideration.

Up to 60% of patients experience recurrence after a first traumatic anterior shoulder dislocation (FTASD), which is often defined as having experienced either dislocation or subluxation. Thus surgical intervention after FTASD is worthy of consideration and is guided by the number of patients who need to receive surgical intervention to prevent 1 redislocation (i.e., number needed to treat), (subjective) health benefit, complication risk, and costs. Operative intervention through arthroscopic stabilization can be successful in reducing recurrence risk in FTASD, as has been shown in multiple randomized controlled trials. Nevertheless, there is a large "gray area" for the indication of arthroscopic stabilization, and it is therefore heavily debated which patients should receive operative treatment. Previous trials showed widely varying redislocation rates in both the intervention and control group, meta-analysis shows 2% to 19% after operative and 20% to 75% after nonoperative treatment, and redislocation rates may not correlate with patient-reported outcomes. The literature is quite heterogeneous, and a major confounder is time to follow-up. Furthermore, there is insufficient standardization of reporting of outcomes and no consensus on definition of risk factors. As a result, surgery is a reasonable intervention for FTASD patients, but in which patients it best prevents redislocation requires additional refinement.

Why do patients with anterior shoulder instability not return to sport after surgery? A systematic review of 63 studies comprising 3545 patients.

Purpose: To review athletes' reasons not to return to sport (RTS) after surgical treatment of anterior shoulder instability, comparing capsulolabral repair and bony reconstruction procedures. The hypothesis is that the most common reason for patients unable to RTS is not due to physical inability of the shoulder. Methods: A systematic review was performed using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. PubMed, Embase/Ovid, Cochrane Database of Systematic Reviews/Wiley, Cochrane Central Register of Controlled Trials/Wiley, SPORTDiscus/Ebsco, and Web of Science/Clarivate Analytics were searched in collaboration with an information specialist up to August 11, 2022. Observational and interventional studies reporting reasons for no RTS following surgical treatment of anterior shoulder instability were included. Quality assessment of studies was conducted using the Methodological Index for Non-Randomized Studies (MINORS) criteria and Risk of Bias (RoB) assessment. Forest plots were generated to show an overview of the proportion shoulder function independent reasons for each study. Results: Sixty-three studies were included reporting on 3545 athletes, of which 2588 (73%) underwent capsulolabral repair versus 957 (27%) who underwent surgical treatment with bony reconstruction procedures. A total of 650 athletes (18%) were unable to RTS. The reason not to RTS was most frequently shoulder function independent (70%) compared to shoulder function dependent (30%) following both capsulolabral repair and bony reconstruction procedures. Most cited reasons for no RTS after capsulolabral repair were fear of reinjury (17%), personal reasons or change of priorities (11%) and retirement/discharge of military service or sports team (10%). Of these reasons, 106 (22%) were not specified other than being shoulder function dependent or shoulder function independent. Most cited reasons for no RTS after bony reconstruction procedures were fear of reinjury (12%), shoulder pain (10%), and retirement/discharge of military service or sports team (9%). Of these reasons, 74 (44%) were not specified other than being shoulder function dependent or shoulder function independent. Forest plots showed a variation from 0% to 100% shoulder independent reasons for both capsulolabral repair and bony reconstruction procedures. Conclusion: The majority of athletes who did not RTS following surgical treatment for anterior shoulder instability did so due to shoulder function independent reasons, such as fear of reinjury. However, there was a high variety between studies and many reasons were unspecified, warranting unified definitions for reasons of patients that do not RTS.

Wide Range in Complication Rates Following Elbow Arthroscopy in Adult and Pediatric Patients: A Systematic Review.

PURPOSE: To perform a systematic review of complications associated with elbow arthroscopy in adults and children. METHODS: A literature search was performed in the PubMed, EMBASE, and Cochrane databases. Studies reporting complications or reoperations after elbow arthroscopy with at least 5 patients were included. Based on the Nelson classification, the severity of complications was categorized as minor or major. Risk of bias was assessed using the Cochrane risk-of-bias tool for randomized clinical trials, and nonrandomized trials were assessed using the Methodological Items for Non-randomized Studies (MINORS) tool. RESULT: A total of 114 articles were included with 18,892 arthroscopies (16,815 patients). A low risk of bias was seen for the randomized studies and a fair quality for the nonrandomized studies. Complication rates ranged from 0% to 71% (median 3%; 95% confidence interval [CI], 2.8%-3.3%), and reoperation rates from 0% to 59% (median 2%; 95% CI, 1.8%-2.2%). A total of 906 complications were observed, with transient nerve palsies (31%) as the most frequent complication. According to Nelson classification, 735 (81%) complications were minor and 171 (19%) major. Forty-nine studies reported complications in adults and 10 studies in children, showing a complication rate ranging from 0% to 27% (median 0%; 95% CI, 0%-0.4%) and 0% to 57% (median 1%; 95% CI, 0.4%-3.5%), respectively. A total of 125 complications were observed in adults, with transient nerve palsies (23%) as the most frequent complication, and 33 in children, with loose bodies after surgery (45%) as the most frequent complication. CONCLUSIONS: Predominantly low-level evidence studies demonstrate varying complication rates (median 3%, range 0%-71%) and reoperation rates (median 2%, range 0%-59%) after elbow arthroscopy. Higher complication rates are observed after more complex surgery. The incidence and type of complications can aid surgeons in patient counseling and refining surgical techniques to further reduce the complication rates. LEVEL OF EVIDENCE: Level IV; systematic review of Level I-IV studies.

Prognostic factors associated with failure to return to sport following primary arthroscopic Bankart repair: a retrospective multicenter study.

BACKGROUND: Even though many studies have been published regarding return-to-sport (RTS) rates following arthroscopic Bankart repair (ABR), evidence regarding prognostic factors for which patients do not RTS is limited. The aim of this study was to identify prognostic factors that are associated with failure to RTS and failure to return to preinjury level of sport (RTPS) following primary ABR. The hypothesis was that prognostic factors for failure to RTS and failure to RTPS would be similar to those predisposing recurrence. METHODS: A multicenter, retrospective case-control study including 6 Dutch hospitals was performed. Consecutive patients who underwent primary ABR between 2014 and 2019 were invited to participate and received a questionnaire. Sports participation was assessed before symptom onset, at 6 months postoperatively, and at final follow-up. Failure to RTS was defined as no return to any sport, and failure to RTPS was defined as no return to the same level (or a higher level) of sport. Prognostic factors for failure to RTS or failure to RTPS were identified using logistic regression. Covariates for the regression analysis were selected based on univariate analyses. RESULTS: This study included 318 patients with a mean follow-up period of 4.2 years (standard deviation, 1.8 years). Of these 318 patients, 26 (8.2%) did not RTS and 100 (31%) did not RTPS. Logistic regression analysis demonstrated that glenoid bone loss (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.04-1.15; P = .001) and overhead use of the shoulder during work (OR, 3.77; 95% CI, 1.45-9.85; P = .007) were prognostic factors for failure to RTS. In addition, it showed that preoperative professional sports level (OR, 2.94; 95% CI, 1.07-8.05; P = .04) and preoperative body mass index (OR, 1.11; 95% CI, 1.01-1.21; P = .04) were prognostic factors for failure to RTPS. Repair of a bony Bankart lesion (OR, 0.35; 95% CI, 0.15-0.81; P = .02) and the presence of an anterior labral periosteal sleeve avulsion (ALPSA) (OR, 0.44; 95% CI, 0.20-0.97; P = .04) were identified as factors that facilitated RTPS. CONCLUSION: This study identified glenoid bone loss and overhead use of the shoulder during work to be associated with failure to RTS. Moreover, preoperative sports level and preoperative body mass index were found to be associated with failure to RTPS. In contrast, a bony Bankart lesion and an anterior labral periosteal sleeve avulsion (ALPSA) lesion facilitated RTPS. Future prospective studies are needed to confirm these factors and determine which part of the effect can be attributed to (failure of) surgical treatment or changes in behavior.

The O'Brien test demonstrates a higher diagnostic value in identifying posteroinferior labral tears than superior labral anterior to posterior (SLAP) tears.

Background: The primary aim was to determine the diagnostic value of the O'Brien test in localizing labral tears of the shoulder. Methods: A consecutive series of patients electing for labral repair between January 2005 and March 2021 were included in this retrospective study. Inclusion criteria were as follows: (1) any patient with a labral tear who was elected for arthroscopic labral repair and (2) had documentation of the O'Brien test in the preoperative evaluation. Exclusion criteria were patients that had a negative arthrographically enhanced computed tomography or magnetic resonance imaging scan. During arthroscopy, the localization and extension of the labral tear was documented in a standardized 12-o'clock configuration. Anteroinferior, posteroinferior, superior labrum anterior to posterior (SLAP), and combined labral tears were documented. The sensitivity, specificity, positive and negative predictive values, accuracy, positive and negative likelihood ratios, receiver operating characteristic curve, and area under the curve were calculated to determine the diagnostic value. Results: The cohort consisted of 271 patients (77% male) and included 105 anteroinferior, 86 posteroinferior, 46 SLAP, and 32 combined parts of the labrum. The mean age at time of surgery was 30 (±10.2) years. The O'Brien test was positive in 142 (52%) patients and showed the highest sensitivity and specificity for the posteroinferior tears (83% and 62%) compared to the anteroinferior (16% and 25%), combined labral parts (69% and 50%), and SLAP (65% and 50%) tears. In addition, receiver operating characteristic-analysis demonstrated a significantly higher area under the curve for posteroinferior tears compared to the other tears (P < .001). Conclusion: The O'Brien test demonstrates more diagnostic value for posteroinferior tears than other labral tears. This includes the SLAP tear, for which the O'Brien test was originally designed. Clinical Relevance: These findings are helpful towards reinterpreting the O'Brien test as well as diagnosing, and more specifically localizing labral tears in clinics.

Predictive value of Gagey's hyperabduction test in identifying inferior glenohumeral ligament lesions.

INTRODUCTION: Clinical tests that can identify inferior glenohumeral ligament (IGHL) complex injuries are indispensable for the diagnosis of shoulder instability. Gagey's hyperabduction test had been developed to diagnose IGHL hyperlaxity, however, it is unclear whether the test is able to accurately diagnose an IGHL lesion. The aim of this study was to (1) determine the diagnostic performance of the Gagey test in identifying an IGHL lesion and (2) determine if a positive Gagey test is more predictive for an anterior or posterior IGHL lesion thanks to the heatmapping of the lesions. It was hypothesized that a Gagey test can accurately predict IGHL lesions, but would not be able to distinguish between anterior and inferior IGHL lesions. METHODS: A retrospective diagnostic accuracy study was conducted including all consecutive patients who underwent glenoid labral repair between January 2005 and September 2021 with a documented Gagey test prior to surgery. Using arthroscopic findings as a reference standard, the diagnostic performance characteristics of the Gagey test for each type of IGHL lesion (anterior, posterior and combined) were calculated and labral heatmapping was used to depict its localisation. RESULTS: A total of 167 patients were included, with a mean age of 29±10 years. The sensitivity, specificity and accuracy of the Gagey test on determining an IGHL lesion were 46%, 38% and 46%, respectively. The positive and negative predictive values were 88% and 7%, respectively. Heatmapping of the labral lesions demonstrated that a positive Gagey test was most predictive of anterior IGHL and axillary pouch tears and non-predictive of posterior IGHL lesions. DISCUSSION: The Gagey test demonstrated a low sensitivity and specificity to identify an IGHL lesion and therefore the hypothesis could not be confirmed. However, the Gagey test has a high positive predictive value to diagnose anterior IGHL lesions. Further prospective research with a more evenly distribution of lesions is needed to investigate the clinical value of the Gagey test to identify these lesions. Based on this data, the Gagey test seems especially important to support the results of other clinical tests such as the apprehension, relocation and surprise tests. LEVEL OF EVIDENCE: III, Retrospective Case-Control study.

"Nearly off-track lesions" or a short distance from the medial edge of the Hill-Sachs lesion to the medial edge of the glenoid track does not seem to be accurate in predicting recurrence after an arthroscopic Bankart repair in a military population: a case-control study.

BACKGROUND: On-track lesions with a short distance from the medial edge of the Hill-Sachs lesion to the medial edge of the glenoid track (nearly off-track) may predispose recurrence after arthroscopic Bankart repair (ABR) in the general population. The aim of this study was to determine if a shorter distance between the medial edge of the Hill-Sachs lesion and the medial edge of the glenoid track could accurately predict recurrence after an ABR in a high-demand military population. It was hypothesized that a shorter distance would not accurately predict recurrence. MATERIALS AND METHODS: A retrospective monocenter case-control study was performed at the Dutch Central Military Hospital. Patients with an on-track Hill-Sachs lesion who underwent a primary ABR between 2014 and 2019 with a minimal follow-up of 2 years and a preoperative magnetic resonance imaging (MRI) assessment received a questionnaire. The primary outcome was recurrence, defined as a complete dislocation or subluxation. Glenoid bone loss was assessed using a linear-based method on MRI. The distance from the medial edge of the Hill-Sachs lesion to the medial edge of the glenoid track was defined as the distance to dislocation (DTD). A receiver operating characteristic curve was created to determine the predictive value of the DTD for recurrence. Logistic regression was used to determine preoperative risk factors that predispose recurrence. Covariates were selected based on univariable analysis and included gender, body mass index, age at surgery and first dislocation, laterality, smoking habits, overhead shoulder activity during work, preoperative dislocations, sports type and level, bony or labral lesions on MRI, and DTD. RESULTS: In total, 80 patients with an average follow-up of 4.8 ± 1.9 years completed the questionnaire and were included in the analyses. Seventeen patients (21%) experienced recurrence at the final follow-up. No difference in DTD was observed among patients who experienced recurrence (9 ± 4 mm) compared with patients who did not (9 ± 5 mm; P = .81). The receiver operating characteristic curve demonstrated no predictive power of DTD for recurrence (area under the curve = 0.49). Smoking at the time of surgery (odds ratio: 3.9; confidence interval: 1.2-12.7; P = .02) and overhead shoulder movement during work (odds ratio: 9.3; confidence interval: 1.1-78.0; P = .04) were associated with recurrence according to the logistic regression analysis. CONCLUSION: A shorter DTD demonstrated no accuracy in predicting recurrence in a military population. Smoking at the time of surgery and overhead shoulder activity during work were associated with recurrence; however, these analyses were underpowered to draw valid conclusions.

High resorption rates following glenoid augmentation procedures do not seem to lead to higher recurrence rates or worse clinical outcomes: a systematic review and meta-analysis.

PURPOSE: Bone augmentation techniques show a relatively high complication rate, which might be due to graft non-union and resorption. It is unclear which augmentation techniques demonstrate the highest amount of non-union and resorption and whether this leads to worse clinical or functional outcomes. Therefore, the aim of this review was (i) to compare non-union and resorption rates between surgical approaches, procedures, graft types, donor sites and fixation methods regarding clinical and functional outcomes and (ii) determine whether high non-union or resorption rates lead to less favorable clinical or functional outcomes. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses statements were followed. PubMed, EMBASE (Ovid) and Cochrane Library were searched on December 15th 2021 for studies examining bone graft non-union or resorption using radiograph or CT following glenoid augmentation to treat anterior shoulder dislocation. RESULTS: The search resulted in 103 inclusions, comprising 5,128 glenoid augmentations. When comparing pooled proportions of bony union, graft fracture rate, hardware failure rate, recurrence rate, return to sports and Rowe score, most results were similar between approaches, procedures, graft types, donor sites and fixation methods. High resorption rates were seen for allograft augmentation (74.3; 95% CI: 39.8-92.7) compared to autograft augmentation (15.5; 95% CI 10.1-23.2), but this was not associated with higher recurrence rates or worse clinical outcomes. Meta-analyses (8 studies; 494 patients) demonstrated no difference in incomplete and complete non-union rates between arthroscopic and open procedures; however, both analyses showed substantial heterogeneity. Higher partial resorption rates were observed on CT (48.0; 95% CI 43.3-52.7) compared to radiograph (14.1; 95% CI 10.9-18.1). Three studies comprising 267 shoulders demonstrated a higher rate of non-union and recurrence in smokers, whereas one study comprising 38 shoulders did not. CONCLUSION: Non-union and resorption rates were similar among procedures, grafts and fixation methods. Higher resorption rates were observed in allografts, but this was not associated with higher recurrence rates or worse clinical outcomes. Pooling data demonstrated substantial heterogeneity and definitions varied among studies, warranting more standardized measuring. LEVEL OF EVIDENCE: IV.

Development and training of a machine learning algorithm to identify patients at risk for recurrence following an arthroscopic Bankart repair (CLEARER): protocol for a retrospective, multicentre, cohort study.

INTRODUCTION: Shoulder instability is a common injury, with a reported incidence of 23.9 per 100 000 person-years. There is still an ongoing debate on the most effective treatment strategy. Non-operative treatment has recurrence rates of up to 60%, whereas operative treatments such as the Bankart repair and bone block procedures show lower recurrence rates (16% and 2%, respectively) but higher complication rates (<2% and up to 30%, respectively). Methods to determine risk of recurrence have been developed; however, patient-specific decision-making tools are still lacking. Artificial intelligence and machine learning algorithms use self-learning complex models that can be used to make patient-specific decision-making tools. The aim of the current study is to develop and train a machine learning algorithm to create a prediction model to be used in clinical practice-as an online prediction tool-to estimate recurrence rates following a Bankart repair. METHODS AND ANALYSIS: This is a multicentre retrospective cohort study. Patients with traumatic anterior shoulder dislocations that were treated with an arthroscopic Bankart repair without remplissage will be included. This study includes two parts. Part 1, collecting all potential factors influencing the recurrence rate following an arthroscopic Bankart repair in patients using multicentre data, aiming to include data from >1000 patients worldwide. Part 2, the multicentre data will be re-evaluated (and where applicable complemented) using machine learning algorithms to predict outcomes. Recurrence will be the primary outcome measure. ETHICS AND DISSEMINATION: For safe multicentre data exchange and analysis, our Machine Learning Consortium adhered to the WHO regulation 'Policy on Use and Sharing of Data Collected by WHO in Member States Outside the Context of Public Health Emergencies'. The study results will be disseminated through publication in a peer-reviewed journal. No Institutional Review Board is required for this study.

Greater tuberosity fractures are not a continuation of Hill-Sachs lesions, but do they have a similar etiology?

Background: It is unclear whether greater tuberosity fractures (GTF) in the setting of a shoulder dislocation are due to an avulsion of the rotator cuff or a result of an extensive Hill-Sachs lesion (HSL). To explore whether these lesions have similar etiology, the primary aim of this study is to compare the postinjury morphology of the proximal humerus after GTF and HSL. Methods: Computed tomography scans of 19 patients with HSL and 18 patients with GTF after first-time shoulder dislocations were analyzed. We assessed the location by measuring height in relation to the highest point of the humerus and angles for the origin (most medial point of lesion), center, and endpoint (most lateral point of lesion) between GTF and HSL and the bicipital groove. For both GTF and HSL, we assessed whether infraspinatus and supraspinatus insertions were involved and whether they were off-track or on-track. Results: Measured from the bicipital groove, HSLs and GTFs have different origins (153˚ vs. 110˚; P < .0001, respectively), centers (125˚ vs. 60˚; P < .0001, respectively), and endpoints (92˚ vs. 37˚; P < .0001, respectively). HSLs had a higher position (0.76 cm vs. 1.71 cm; P < .0001), involved the supraspinatus footprint less often (16% vs. 72%; P = .0008), and were less likely to be off-track (31% vs. 94%; P = .0002). Half of the GTF were on the lateral side of the glenoid track and thus extra-capsular, versus 0% of HSL. Conclusion: HSLs and GTFs have different anatomical characteristics and thus GTFs are likely to be distinct from extensive HSLs.

Bony reconstruction after failed labral repair is associated with higher recurrence rates compared to primary bony reconstruction: a systematic review and meta-analysis of 1319 shoulders in studies with a minimum of 2-year follow-up.

BACKGROUND: There is uncertainty with regard to the optimal revision procedure after failed labral repair for anterior shoulder instability. An overview of outcomes of these procedures with quantitative analysis is not available in literature. The aim of this review is (1) to compare recurrence rates after revision labral repair (RLR) and revision bony reconstruction (RBR), both following failed labral repair. In addition, (2) recurrence rates after RBR following failed labral repair and primary bony reconstruction (PBR) are compared to determine if a previous failed labral repair influences the outcomes of the bony reconstruction. METHODS: Randomized controlled trials and cohort studies with a minimum follow-up of 2 years and reporting recurrence rates of (1) RBR following failed labral repair and PBR and/or (2) RLR following failed labral repair and RBR following failed labral repair were identified by searching PubMed, Embase/Ovid, Cochrane Database of Systematic Reviews/Wiley, Cochrane Central Register of Controlled Trials/Wiley, and Web of Science/Clarivate Analytics. RESULTS: Thirteen studies met the inclusion criteria and comprised 1319 shoulders. Meta-analyses showed that RBR has a significantly higher recurrence rate than PBR (risk ratio [RR] 0.51, P < .008) but found no significant difference in the recurrence rates for RLR and RBR (RR 1.40, P < .49). Also, no significant differences were found between PBR and RBR in return to sport (RR 1.07, P < .41), revision surgery (RR 0.8, P < .44), and complications (RR 0.84, P < .53). Lastly, no significant differences between RLR and RBR for revision surgery (RR 3.33, P < .19) were found. CONCLUSION: The findings of this meta-analyses show that (1) RBR does not demonstrate a significant difference in recurrence rates compared with RLR and that (2) RBR has a significantly higher recurrence rate than PBR.

Recurrence in traumatic anterior shoulder dislocations increases the prevalence of Hill-Sachs and Bankart lesions: a systematic review and meta-analysis.

PURPOSE: The extent of shoulder instability and the indication for surgery may be determined by the prevalence or size of associated lesions. However, a varying prevalence is reported and the actual values are therefore unclear. In addition, it is unclear whether these lesions are present after the first dislocation and whether or not these lesions increase in size after recurrence. The aim of this systematic review was (1) to determine the prevalence of lesions associated with traumatic anterior shoulder dislocations, (2) to determine if the prevalence is higher following recurrent dislocations compared to first-time dislocations and (3) to determine if the prevalence is higher following complete dislocations compared to subluxations. METHODS: PubMed, EMBASE, Cochrane and Web of Science were searched. Studies examining shoulders after traumatic anterior dislocations during arthroscopy or with MRI/MRA or CT published after 1999 were included. A total of 22 studies (1920 shoulders) were included. RESULTS: The proportion of Hill-Sachs and Bankart lesions was higher in recurrent dislocations (85%; 66%) compared to first-time dislocations (71%; 59%) and this was statistically significant (P < 0.01; P = 0.05). No significant difference between recurrent and first-time dislocations was observed for SLAP lesions, rotator-cuff tears, bony Bankart lesions, HAGL lesions and ALPSA lesions. The proportion of Hill-Sachs lesions was significantly higher in complete dislocations (82%) compared to subluxations (54%; P < 0.01). CONCLUSION: Higher proportions of Hill-Sachs and Bankart were observed in recurrent dislocations compared to first-time dislocations. No difference was observed for bony Bankart, HAGL, SLAP, rotator-cuff tear and ALPSA. Especially when a Hill-Sachs or Bankart is present after first-time dislocation, early surgical stabilization may need to be considered as other lesions may not be expected after recurrence and to limit lesion growth. However, results should be interpreted with caution due to substantial heterogeneity and large variance. LEVEL OF EVIDENCE: IV.

Antihypertensive drugs demonstrate varying levels of hip fracture risk: A systematic review and meta-analysis.

OBJECTIVE: By aggregating the literature, we evaluated the association between use of specific antihypertensive drugs and the risk of hip fractures compared with nonuse. STUDY DESIGN AND SETTING: We systematically searched the Pubmed, Embase, and Cochrane databases from inception of each database until July 30, 2020 to identify articles including patients 18 years of age or older reporting on the association between antihypertensive drugs and the risk of hip fracture. Antihypertensive drugs were restricted to thiazides; beta-blockers; calcium-channel blockers; angiotensin-converting enzyme (ACE) inhibitors; and angiotensin receptor blockers. Nonusers encompass all patients that are not using the specific antihypertensive drug that has been reported. Unadjusted odds ratios with 95% confidence intervals (CIs) of the association between antihypertensive drug use and hip fractures were reported. Meta-analysis was performed when a minimum of five studies were identified for each antihypertensive drug class. Quality assessment was done using ROBINS-I tool. The GRADE approach was used to evaluate the certainty of the evidence. RESULTS: Of 962 citations, 22 observational studies were included; 9 studies had a cohort design and 13 studies were case-control studies. No randomized controlled trials were identified. We found very low certainty of evidence that both thiazides (pooled odds ratio: 0.85, 95% CI 0.73 to 0.99, p = 0.04) as well as beta-blockers (pooled odds ratio: 0.88, 95% CI 0.79 to 0.98, p = 0.02) were associated with a reduced hip fracture risk as compared to specific nonuse. One study, reporting on angiotensin receptor blockers, also suggested a protective effect for hip fractures, whereas we found conflicting findings in four studies for calcium-channel blockers and in two studies for ACE inhibitors. CONCLUSION: Among 22 observational studies, we found very low certainty of evidence that, compared to specific nonuse of antihypertensive drugs, use of thiazides, beta-blockers, and angiotensin receptor blockers were associated with a reduced protective hip fracture risk, while conflicting findings for calcium-channel blockers and ACE inhibitors were found. Given the low quality of included studies, further research -randomized controlled trials- are needed to definitively assess the causal relationship between specific antihypertensive drug classes and (relatively infrequent) hip fractures.