A Scapular Statistical Shape Model can Reliably Predict Premorbid Glenoid Morphology in Conditions of Severe Glenoid Bone Loss.

BACKGROUND: Knowledge of premorbid glenoid parameters at the time of shoulder arthroplasty, such as inclination, version, joint line position, height, and width, can assist with implant selection, implant positioning, metal augment sizing and/or bone graft dimensions. The objective of this study was to validate a scapular statistical shape model (SSM) in predicting patient-specific glenoid morphology in scapulae with clinically relevant glenoid erosion patterns. METHODS: Computer tomography scans of 30 healthy scapulae were obtained and used as the control group. Each scapula was then virtually eroded to create seven erosion patterns (Walch A1, A2, B2, B3, D, Favard E2, and E3). This resulted in 210 uniquely eroded glenoid models, forming the eroded glenoid group. A scapular SSM, created from a different database of 85 healthy scapulae, was then applied to each eroded scapula to predict the premorbid glenoid morphology. The premorbid glenoid inclination, version, height, width, radius of best fit sphere, and glenoid joint line position were automatically calculated for each of the 210 eroded glenoids. The mean values for all outcome variables were compared across all erosion types between the healthy, eroded, and SSM predicted groups using a two-way repeated-measures analysis of variance. RESULTS: The SSM was able to predict the mean premorbid glenoid parameters of the eroded glenoids with a mean absolute difference of 3±2° for inclination, 3±2° for version, 2±1mm for glenoid height, 2±1mm for glenoid width, 5±4mm for radius of best fit sphere, and 1±1mm for glenoid joint line. The mean SSM predicted values for inclination, version, height, width, and radius were not significantly different than the control group (P>0.05). DISCUSSION: A statistical shape model has been developed that can reliably predict premorbid glenoid morphology and glenoid indices in patients with common glenoid erosion patterns. This technology can serve as a useful template to visually represent the premorbid healthy glenoid in patients with severe glenoid bony erosions. Knowledge of the premorbid glenoid preoperatively can assist with implant selection, positioning, and sizing.

The Kouvalchouk Procedure versus Distal Tibial Allograft for Treatment of Posterior Shoulder Instability: The Deltoid "Hammock" Effect Exists.

BACKGROUND: In 1993, Kouvalchouk described an acromial bone block with a pedicled deltoid flap for the treatment of posterior shoulder instability. This procedure provides a "double blocking" effect in that the acromial autograft restores posterior glenoid bone loss and the deltoid flap functions as a muscular "hammock" resembling the sling effect of the conjoint in the Latarjet procedure. The primary aim of this study was to compare the Kouvalchouk procedure to distal tibial allograft (DTA) reconstruction for the management of posterior shoulder instability with associated bone loss, while the secondary aim was to evaluate the deltoid hammock effect. s METHODS: Ten upper extremity cadavers were evaluated using a validated shoulder testing apparatus in 0° and 60° of glenohumeral abduction in the scapular plane. Testing was first performed on the normal shoulder state and was followed by the creation of a 20% posterior glenoid defect. Subsequently, the Kouvalchouk and DTA procedures were conducted. Forces of 0N, 5N, 10N and 15N were applied to the posterior deltoid tendinous insertion on the Kouvalchouk graft along the physiological muscle line-of-action to evaluate the 'hammock" effect of this procedure. Testing was additionally performed on the Kouvalchouk bone graft with the deltoid muscle sectioned from its bony attachment. For all test states, a posteriorly directed force was applied to the humeral head perpendicular to the direction of the glenoid bone defect, with the associated translation quantified using an optical tracking system. The outcome variable was posterior translation of the humeral head at an applied force magnitude of 30N. RESULTS: The Kouvalchouk procedure with the loaded deltoid flap (10N: P=0.039 and 15N: P<0.001) was significantly better at reducing posterior humeral head translation than the DTA. Overall, increased glenohumeral stability was observed with increased force applied to the posterior deltoid flap in the Kouvalchouk procedure. The 15N Kouvalchouk was most effective at preventing posterior humeral translation, and the difference was statistically significant compared with the 20% glenoid defect (P=0.003), detached Kouvalchouk (P<0.001), and 0N Kouvalchouk (P<0.001). The 15N Kouvalchouk procedure restored posterior shoulder joint stability to near normal levels, such that it was not significantly different from the intact state (P=0.203). CONCLUSIONS: The Kouvalchouk procedure with load applied to the deltoid was found to be biomechanically superior to the DTA for the management of posterior shoulder instability with associated bone loss. Additionally, the results confirmed the presence and effectiveness of the deltoid "hammock" effect.

Bridge Plating is an Effective Adjunct Treatment for Complex Elbow Instability.

BACKGROUND: Managing persistent elbow instability and chronic dislocations presents challenges despite traditional treatments. Supplementary methods like immobilization and various fixations, though common, can carry high complication rates. This study assesses the efficacy of bridge plating in treating complex elbow instability through a retrospective review of patients. Data on characteristics, treatment duration, range of motion, complications, and evaluation scores were analyzed, providing insights into outcomes complications associated with bridge plating. RESULTS: Eleven patients were reviewed at an average follow-up of 80 ± 68 weeks. postoperatively. The average age was 53±14 years and there were 5 females and 6 males. The average BMI was 38. Bridge plating was used for a spectrum of complex elbow injuries. The average time from injury to bridge plating in acute cases was 29±19 days and 344±381 days in chronic cases. The average duration of bridge plating was 121 ± 72 days. At the time of plate removal, mean intraoperative elbow motion was extension 58±12°, flexion 107±14°, supination 66±23° and pronation 60±26°. At the latest follow-up visit, average elbow motion was extension 37±22°, Flexion 127± 17°, supination 72±15° and pronation 63±18°. There were 6 complications (55%); heterotopic ossification, ulnar neuropathy, wound failure over the plate in a thin patient, an ulnar shaft peri-prosthetic fracture due to a seizure induced fall, and elbow subluxation despite bridge plate fixation. One patient sustained a fracture of a 3.5mm locking bridge plate. One patient required a contracture release for persistent stiffness. Four of these complications can be directly attributed to the use of the bridge plate (36%). At final follow-up, the average patient rated elbow evaluation score was 34, with 0 indicating no pain and disability. The average single assessment numeric evaluation score was 66% for the 8 patients who had this available, with 100% being the best possible attainable score. CONCLUSION: Bridge plating effectively maintains joint reduction in selected complex elbow instability cases. However, patients with bridge plates often require a second surgery for removal and experience high rates of general complications due to the complexity of their condition.

Strength after the arthroscopic Latarjet procedure: Are shoulder internal rotation, elbow flexion & supination strength decreased?

Background: The Latarjet procedure is an effective shoulder stabilizing surgery, however, the procedure results in an alteration of anatomy that may result in shoulder and elbow weakness. Thus, the purpose of this study was to assess post-operative shoulder and elbow strength after the Latarjet procedure. We hypothesized that shoulder and elbow strength are not affected after the procedure. Methods: The study group consisted of patients that had undergone the arthroscopic Latarjet procedure. An isokinetic dynamometer was used to evaluate the strength of bilateral shoulder internal rotation, elbow flexion, forearm supination using peak torque (N/m), as well as grip strength (kilograms). Shoulder range of motion and the potential effects of hand dominance were further analysed. Results: Nineteen patients with a mean age of 29 years and an average follow up of 47 months were included. Shoulder internal rotation strength, elbow flexion and forearm supination strength and grip strength were not significantly different when compared to the non-operative side (p > 0.13). The range of shoulder external rotation was significantly reduced (p < 0.001) on the Latarjet side. Conclusion: The results from this study demonstrate no statistically significant differences in the strength of shoulder internal rotation, elbow flexion, forearm supination or grip strength despite the surgical alterations to the subscapularis and conjoint tendon.

Scapular morphology variation affects reverse total shoulder arthroplasty biomechanics. A predictive simulation study using statistical and musculoskeletal shoulder models.

Reverse total shoulder arthroplasty (RTSA) accounts for over half of shoulder replacement surgeries. At present, the optimal position of RTSA components is unknown. Previous biomechanical studies have investigated the effect of construct placement to quantify mobility, stability and functionality postoperatively. While studies have provided valuable information on construct design and surgical placement, they have not systematically evaluated the importance of scapular morphology on biomechanical outcomes. The aim of this study was to assess the influence of scapular morphology variation on RTSA biomechanics using statistical models, musculoskeletal modeling and predictive simulation. The scapular geometry of a musculoskeletal model was altered across six modes of variation at four levels (±1 and ±3 SD) from a clinically derived statistical shape model. For each model, a standardized virtual surgery was performed to place RTSA components in the same relative position on each model then implemented in 50 predictive simulations of upward and lateral reaching tasks. Results showed morphology affected functional changes in the deltoid moment arms and recruitment for the two tasks. Variation of the anatomy that reduced the efficiency of the deltoids showed increased levels of muscle force production, joint load magnitude and shear. These findings suggest that scapular morphology plays an important role in postoperative biomechanical function of the shoulder with an implanted RTSA. Furthermore a "one-size-fits-all" approach for construct surgical placement may lead to suboptimal patient outcomes across a clinical population. Patient glenoid as well as scapular anatomy may need to be carefully considered when planning RTSA to optimize postoperative success.

Validation of mixed-reality surgical navigation for glenoid axis pin placement in shoulder arthroplasty using a cadaveric model.

BACKGROUND: Mixed reality may offer an alternative for computer-assisted navigation in shoulder arthroplasty. The purpose of this study was to determine the accuracy and precision of mixed-reality guidance for the placement of the glenoid axis pin in cadaver specimens. This step is essential for accurate glenoid placement in total shoulder arthroplasty. METHODS: Fourteen cadaveric shoulders underwent simulated shoulder replacement surgery by 7 experienced shoulder surgeons. The surgeons exposed the cadavers through a deltopectoral approach and then used mixed-reality surgical navigation to insert a guide pin in a preplanned position and trajectory in the glenoid. The mixed-reality system used the Microsoft Hololens 2 headset, navigation software, dedicated instruments with fiducial marker cubes, and a securing pin. Computed tomography scans obtained before and after the procedure were used to plan the surgeries and determine the difference between the planned and executed values for the entry point, version, and inclination. One specimen had to be discarded from the analysis because the guide pin was removed accidentally before obtaining the postprocedure computed tomography scan. RESULTS: Regarding the navigated entry point on the glenoid, the mean difference between planned and executed values was 1.7 ± 0.8 mm; this difference was 1.2 ± 0.6 mm in the superior-inferior direction and 0.9 ± 0.8 mm in the anterior-posterior direction. The maximum deviation from the entry point for all 13 specimens analyzed was 3.1 mm. Regarding version, the mean difference between planned and executed version values was 1.6° ± 1.2°, with a maximum deviation in version for all 13 specimens of 4.1°. Regarding inclination, the mean angular difference was 1.7° ± 1.5°, with a maximum deviation in inclination of 5°. CONCLUSIONS: The mixed-reality navigation system used in this study allowed surgeons to insert the glenoid guide pin on average within 2 mm from the planned entry point and within 2° of version and inclination. The navigated values did not exceed 3 mm or 5°, respectively, for any of the specimens analyzed. This approach may help surgeons more accurately place the definitive glenoid component.

Stemless reverse humeral component neck-shaft angle has an influence on initial fixation.

BACKGROUND: Stemless anatomic humeral components are commonly used and are an accepted alternative to traditional stemmed implants in patients with good bone quality. Presently, little literature exists on the design and implantation parameters that influence primary time-zero fixation of stemless reverse humeral implants. Accordingly, this finite element analysis study assessed the surgical implantation variable of neck-shaft angle, and its effect on the primary time-zero fixation of reversed stemless humeral implants. METHODS: Eight computed tomography-derived humeral finite element models were used to examine a generic stemless humeral implant at varying neck-shaft angles of 130°, 135°, 140°, 145°, and 150°. Four loading scenarios (30° shoulder abduction with neutral forearm rotation, 30° shoulder abduction with forearm supination, a head-height lifting motion, and a single-handed steering motion) were employed. Implantation inclinations were compared based on the maximum bone-implant interface distraction detected after loading. RESULTS: The implant-bone distraction was greatest in the 130° neck-shaft angle implantation cases. All implant loading scenarios elicited significantly lower micromotion magnitudes when neck-shaft angle was increased (P = .0001). With every 5° increase in neck-shaft angle, there was an average 17% reduction in bone-implant distraction. CONCLUSIONS: The neck-shaft angle of implantation for a stemless reverse humeral component is a modifiable parameter that appears to influence time-zero implant stability. Lower, more varus, neck-shaft angles increase bone-implant distractions with simulated activities of daily living. It is therefore suggested that humeral head osteotomies at a higher neck-shaft angle may be beneficial to maximize stemless humeral component stability.

Proximal Humerus Fractures: How to Achieve Best Outcomes.

The treatment of proximal humerus fractures remains controversial. Although treatment modalities may vary, the goal of obtaining the best outcomes for patients remains the same. Most proximal humerus fractures can be treated nonsurgically but should still be managed actively. Deciding on surgical management requires a good understanding of indications and options. Indications for open reduction and internal fixation include younger or active patients with displaced two-, three-, and four-part fractures as well as fracture-dislocations with head-split patterns. Obtaining ideal outcomes requires anatomic reduction with restoration of the medial calcar as well as optimal position of implants to favor biomechanical stability. Reverse total shoulder arthroplasty is indicated for patients with severe and displaced fractures in older or low-demand patients. Obtaining the best functional outcomes depends on implant position, tuberosity healing, and early surgical intervention. Regardless of the treatment modality, these fractures can be challenging, and proper patient rehabilitation must be implemented. Future research will focus on patient selection and improving surgical techniques to maximize outcomes.

Developing a machine learning algorithm to predict the probability of aseptic loosening of the glenoid component after anatomical total shoulder arthroplasty: protocol for a retrospective, multicentre study.

INTRODUCTION: Despite technological advancements in recent years, glenoid component loosening remains a common complication after anatomical total shoulder arthroplasty (ATSA) and is one of the main causes of revision surgery. Increasing emphasis is placed on the prevention of glenoid component failure. Previous studies have successfully predicted range of motion, patient-reported outcomes and short-term complications after ATSA using machine learning methods, but an accurate predictive model for (glenoid component) revision is currently lacking. This study aims to use a large international database to accurately predict aseptic loosening of the glenoid component after ATSA using machine learning algorithms. METHODS AND ANALYSIS: For this multicentre, retrospective study, individual patient data will be compiled from previously published studies reporting revision of ATSA. A systematic literature search will be performed in Medline (PubMed) identifying all studies reporting outcomes of ATSA. Authors will be contacted and invited to participate in the Machine Learning Consortium by sharing their anonymised databases. All databases reporting revisions after ATSA will be included, and individual patients with a follow-up less than 2 years or a fracture as the indication for ATSA will be excluded. First, features (predictive variables) will be identified using a random forest feature selection. The resulting features from the compiled database will be used to train various machine learning algorithms (stochastic gradient boosting, random forest, support vector machine, neural network and elastic-net penalised logistic regression). The developed and validated algorithms will be evaluated across discrimination (c-statistic), calibration, the Brier score and the decision curve analysis. The best-performing algorithm will be used to create an open-access online prediction tool. ETHICS AND DISSEMINATION: Data will be collected adhering to the WHO regulation on data sharing. An Institutional Review Board review is not applicable. The study results will be published in a peer-reviewed journal.

Reverse shoulder arthroplasty: State-of-the-art.

The reverse shoulder arthroplasty conceived by Paul Grammont in 1985 has gradually gained popularity as a treatment for multiple shoulder diseases. Unlike previous reverse shoulder prosthesis characterized by unsatisfactory results and a high glenoid implant failure rate, the Grammont design has immediately shown good clinical outcomes. This semi constrained prosthesis solved the issues of the very first designs by medializing and distalizing the center of rotation with an increased stability of the replacement of the component. The indication was initially limited to cuff tear arthropathy (CTA). It has then been expanded to irreparable massive cuff tears and displaced humeral head fractures. The most frequent problems of this design are a limited postoperative external rotation and scapular notching. Different modifications to the original Grammont design have been proposed with the aim of decreasing the risk of failure and complications and improving the clinical outcomes. Both the position and version/inclination of the glenosphere and the humeral configuration (e.g. neck shaft angle) influence the RSA outcomes. A lateralized glenoid (whether with bone or metal) and a 135° Inlay system configuration leads to a moment arm which is the closest to the native shoulder. Clinical research will focus on implant designs reducing bone adaptations and revision rate, strategies to prevent more effectively infections. Furthermore, there is still room for improvement in terms of better postoperative internal and external rotations and clinical outcomes after RSA implanted for humeral fracture and revision shoulder arthroplasty.

Statistical Shape and Bone Property Models of Clinical Populations as the Foundation for Biomechanical Surgical Planning: Application to Shoulder Arthroplasty.

This work developed, validated, and compared statistical shape, statistical intensity, and statistical shape and intensity models (SSMs, SIMs, SSIMs) of scapulae from a clinical population. SSMs efficiently describe bone shape variation while SIMs describe bone material property variation, and SSIM's combine description of both variables. This work establishes these models' efficacy and whether they can be used in surgical planning. Models were developed using shoulder arthroplasty data of patients with bone erosion, which is challenging to treat and would benefit from improved surgical planning. Models were created using previously validated nonrigid registration and material property assignment processes that were optimized for scapula characteristics. The models were assessed using standard metrics, anatomical measurements, and correlation analyses. The SSM and SIM specificity and generalization error metrics were 3.4 mm and <1 mm and 184 HU and 156 HU, respectively. The SSIM did not achieve the same level of performance as the SSM and SIM in this study (e.g., shape generalization: SSIM-2.2 mm versus SSM-<1 mm). Anatomical correlation analysis showed that the SSM more effectively and efficiently described shape variation compared to the SSIM. The SSM and SIM modes of variation were not strongly correlated (e.g., rmax = 0.56 for modes explaining ≤2.1% of variance). The SSIM is outperformed by the SSM and SIM and the latter two are not strongly correlated; therefore, using the SSM and SIM in conjunction will generate synthetic bone models with realistic characteristics and thus can be used for biomechanical surgical planning applications.

Mixed reality visualization in shoulder arthroplasty: is it better than traditional preoperative planning software?

BACKGROUND: Preoperative traditional software planning (TSP) is a method used to assist surgeons with implant selection and glenoid guide-pin insertion in shoulder arthroplasty. Mixed-Reality (MR) is a new technology that uses digital holograms of the preoperative plan and guide-pin trajectory projected into the operative field. The purpose of this study was to compare TSP to MR in a simulated surgical environment involving insertion of guide-pins into models of severely deformed glenoids. METHODS: Eight surgeons inserted guide-pins into eight randomized three-dimensional-printed severely eroded glenoid models in a simulated surgical environment using either TSP or MR. In total, 128 glenoid models were used and statistically compared. The outcomes compared between techniques included procedural time, difference in guide-pin start point, difference in version and inclination, and surgeon confidence via a confidence rating scale. RESULTS: When comparing traditional preoperative software planning to MR visualization as techniques to assist surgeons in glenoid guide pin insertion, there were no statistically significant differences in terms of mean procedure time (P=0.634), glenoid start-point (TSP = 2.2 ± 0.2 mm , MR = 2.1 ± 0.1 mm; P=0.760), guide-pin orientation (P=0.586), or confidence rating score (P=0.850). CONCLUSIONS: The results demonstrate that there were no significant differences between traditional preoperative software planning and MR visualization for guide-pin placement into models of eroded glenoids. A perceived benefit of MR is the real-time intraoperative visibility of the surgical plan and the patient's anatomy; however, this did not translate into decreased procedural time or improved guide-pin position. Level of evidence: Basic Science Study; Biomechanics.

Evaluation and treatment of postoperative periprosthetic humeral fragility fractures.

Postoperative periprosthetic humeral shaft fractures represent a growing and difficult complication to treat given the aging patient population and associated bone loss. Determining the best treatment option is multifactorial, including patient characteristics, fracture pattern, remaining bone stock, and implant stability. Possible treatment options include nonoperative management with bracing or surgical intervention. Nonoperative treatment has been shown to have higher nonunion rates, thus should only be selected for a specific patient population with minimally displaced fractures or those that are unfit for surgery. Surgical management is recommended with prosthetic loosening, fracture nonunion, or failure of nonoperative treatment. Surgical options include open reduction and internal fixation, revision arthroplasty, or hybrid fixation. Careful evaluation, decision making, and planning is required in the treatment of these fractures.

Balancing clinician and patient priorities for total shoulder replacement preoperative education programs.

OBJECTIVE: To investigate patient and clinician preferences regarding a preoperative educational program for patients undergoing shoulder replacement surgery. METHODS: This study used a cross-sectional survey of patients awaiting shoulder replacement surgery and clinicians. The survey was comprised of 41 questions for patients and clinicians, regarding preferences for receiving information, content preferences and device preferences. Descriptive statistics were reported for survey questions. RESULTS: 180 patients and 175 clinicians completed the survey. Patients and clinicians' top choices for ways to receive information were: in-person, website and booklets, with use of CD/DVD being extremely unlikely. Patients and clinicians had different preferences regarding content choices. Patients rated the following content topics as important to include in a program: including other patient's previous experiences with this surgery (83 % patients; 40 % clinicians), information for caregivers (84 % patients; 65 % clinicians), expectations for hospital stay (89 % patients; 57 % clinicians), process of anesthesia (87 % patients; 51 % clinicians), and how the surgery is performed (94 % patients; 60 % clinicians). CONCLUSIONS: Clinicians and patients have differing priorities and perspectives on the content and delivery of preoperative education programs, however, therapeutic goals and accessibility should be considered when designing programs. PRACTICE IMPLICATIONS: Creating education programs should include the lens of both clinicians and patients.

Arthroscopic reduction and internal fixation of capitellar and trochlear fractures: A case series.

Background: In a simple isolated capitellar/trochlear fracture without extensive posterior comminution, arthroscopic reduction and internal fixation (ARIF) can provide an alternative option to open reduction internal fixation. The purpose of this retrospective case series was to report on the technique and outcomes of arthroscopic reduction and internal fixation of capitellar/trochlear fractures. Methods: All patients that underwent ARIF at a single upper extremity referral centre in the last twenty years were reviewed. Patient demographics, preoperative, intraoperative, and postoperative records were obtained through chart review and telephone followup. Results: Ten cases of ARIF were identified over a twenty year period performed by two surgeons. The average age of patients was 37 years (17-63 years), with nine females and one male. With an average followup of eight years, nine of ten patients had a mean range of motion from 0 to 142 degrees. Their average MEPI and PREE score were 93 ± 7 and 8 ± 14, respectively. Four patients had focal cartilage collapse with three that required a reoperation. There were no infections, nonunions, or arthroscopy related complications. Conclusion: ARIF offers an alternative to ORIF for capitellar/trochlear fractures producing good results while providing better visualization of the fracture reduction and minimizing soft tissue dissection.

Stress shielding following stemless anatomic total shoulder arthroplasty.

Background: Finite element analysis has suggested that stemless implants may theoretically decrease stress shielding. The purpose of this study was to assess the radiographic proximal humeral bone adaptations seen following stemless anatomic total shoulder arthroplasty. Methods: A retrospective review of 152 prospectively followed stemless total shoulder arthroplasty utilizing a single implant design was performed. Anteroposterior and lateral radiographs were reviewed at standard time points. Stress shielding was graded as mild, moderate, and severe. The effect of stress shielding on clinical and functional outcomes was assessed. Also, the influence of subscapularis management on the occurrence of stress shielding was determined. Results: At 2 years postoperatively, stress shielding was noted in 61 (41%) shoulders. A total of 11 (7%) shoulders demonstrated severe stress shielding with 6 occurring along the medial calcar. There was one instance of greater tuberosity resorption. At the final follow-up, no humeral implants were radiographically loose or migrated. There was no statistically significant difference in clinical and functional outcomes between shoulders with and without stress shielding. Patients undergoing a lesser tuberosity osteotomy had lower rates of stress shielding, which was statistically significant (p = 0.021). Discussion: Stress shielding does occur at higher rates than anticipated following stemless total shoulder arthroplasty, but was not associated with implant migration or failure at 2 years follow-up. Level of evidence: IV, Case series.

Indomethacin for heterotopic ossification prophylaxis following surgical treatment of elbow trauma: a randomized controlled trial.

BACKGROUND: Heterotopic ossification is a frequent complication following surgical treatment of elbow trauma. The use of indomethacin to prevent heterotopic ossification is reported in the literature; however, its effectiveness is controversial. The purpose of this randomized, double-blind, placebo-controlled study was to determine whether indomethacin is effective in reducing the incidence and severity of heterotopic ossification after surgical management of elbow trauma. METHODS: Between February 2013 and April 2018, 164 eligible patients were randomized to receive postoperative indomethacin or placebo medication. The primary outcome was the incidence of heterotopic ossification on elbow radiographs at 1-year follow-up. Secondary outcomes included the Patient Rated Elbow Evaluation score, Mayo Elbow Performance Index score, and Disabilities of the Arm, Shoulder and Hand score. Range of motion, complications, and nonunion rates were also obtained. RESULTS: At 1-year follow-up, there was no significant difference in the incidence of heterotopic ossification between the indomethacin group (49%) and the control group (55%) (relative risk, 0.89; P = .52). There were no significant differences in postoperative Patient Rated Elbow Evaluation, Mayo Elbow Performance Index, and Disabilities of the Arm, Shoulder and Hand scores or range of motion (P = .16). The complication rate was 17% in both the treatment and control groups (P > .99). There were no nonunions in either group. CONCLUSION: This Level I study demonstrated that indomethacin prophylaxis against heterotopic ossification in the setting of surgically treated elbow trauma was not significantly different from placebo.

Developing a machine learning algorithm to predict probability of retear and functional outcomes in patients undergoing rotator cuff repair surgery: protocol for a retrospective, multicentre study.

INTRODUCTION: The effectiveness of rotator cuff tear repair surgery is influenced by multiple patient-related, pathology-centred and technical factors, which is thought to contribute to the reported retear rates between 17% and 94%. Adequate patient selection is thought to be essential in reaching satisfactory results. However, no clear consensus has been reached on which factors are most predictive of successful surgery. A clinical decision tool that encompassed all aspects is still to be made. Artificial intelligence (AI) and machine learning algorithms use complex self-learning models that can be used to make patient-specific decision-making tools. The aim of this study is to develop and train an algorithm that can be used as an online available clinical prediction tool, to predict the risk of retear in patients undergoing rotator cuff repair. METHODS AND ANALYSIS: This is a retrospective, multicentre, cohort study using pooled individual patient data from multiple studies of patients who have undergone rotator cuff repair and were evaluated by advanced imaging for healing at a minimum of 6 months after surgery. This study consists of two parts. Part one: collecting all potential factors that might influence retear risks from retrospective multicentre data, aiming to include more than 1000 patients worldwide. Part two: combining all influencing factors into a model that can clinically be used as a prediction tool using machine learning. ETHICS AND DISSEMINATION: For safe multicentre data exchange and analysis, our Machine Learning Consortium adheres 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. Institutional Review Board approval does not apply to the current study protocol.

Comparison of clinical-CT segmentation techniques for measuring subchondral bone cyst volume in glenohumeral osteoarthritis.

PURPOSE: This study aimed to assess the accuracy and reproducibility of four common segmentation techniques measuring subchondral bone cyst volume in clinical-CT scans of glenohumeral OA patients. METHODS: Ten humeral head osteotomies collected from cystic OA patients, having undergone total shoulder arthroplasty, were scanned within a micro-CT scanner, and corresponding preoperative clinical-CT scans were gathered. Cyst volumes were measured manually in micro-CT and served as a reference standard (n = 13). Respective cyst volumes were measured on the clinical-CT scans by two independent graders using four segmentation techniques: Qualitative, Edge Detection, Region Growing, and Thresholding. Cyst volume measured in micro-CT was compared to the different clinical-CT techniques using linear regression and Bland-Altman analysis. Reproducibility of each technique was assessed using intraclass correlation coefficient (ICC). RESULTS: Each technique outputted lower volumes on average than the reference standard (-0.24 to -3.99 mm3). All linear regression slopes and intercepts were not significantly different than 1 and 0, respectively (p < 0.05). Cyst volumes measured using Qualitative and Edge Detection techniques had the highest overall agreement with reference micro-CT volumes (mean discrepancy: 0.24, 0.92 mm3). These techniques showed good to excellent reproducibility between graders. CONCLUSIONS: Qualitative and Edge Detection techniques were found to accurately and reproducibly measure subchondral cyst volume in clinical-CT. These findings provide evidence that clinical-CT may accurately gauge glenohumeral cystic presence, which may be useful for disease monitoring and preoperative planning. LEVEL OF EVIDENCE: Retrospective cohort Level 3 study.

How does computed tomography inform our understanding of shoulder kinematics? A structured review.

The objective of this structured review was to review how computed tomography (CT) scanning has been used to measure the kinematics of the shoulder. A literature search was conducted using Evidence-based Medicine Reviews (Embase) and PubMed. In total, 29 articles were included in the data extraction process. Forty percent of the studies evaluated healthy participants' shoulder kinematics. The glenohumeral joint was the most studied, followed by the scapulothoracic, acromioclavicular, and sternoclavicular joints. Three-dimensional computed tomography (3DCT) and 3DCT with biplane fluoroscopy are the two primary imaging techniques that have been used to measure shoulder joints' motion under different conditions. Finally, many discrepancies in the reporting of the examined motions were found. Different authors used different perspectives and planes to report similar motions, which results in confusion and misunderstanding of the actual examined motion. The use of 3DCT has been widely used in the examination of shoulder kinematics in a variety of populations with varying methods employed. Future work is needed to extend these methodologies to include more diverse populations, to examine the shoulder complex as a whole, and to standardize their reporting of motion examined to make study to study comparisons possible.