3-dimensionally printed patient-specific glenoid drill guides vs. standard nonspecific instrumentation: a randomized controlled trial comparing the accuracy of glenoid component placement in anatomic total shoulder arthroplasty.

BACKGROUND: Traditional, commercially sourced patient-specific instrumentation (PSI) systems for shoulder arthroplasty improve glenoid component placement but can involve considerable cost and outsourcing delays. The purpose of this randomized controlled trial was to compare the accuracy of glenoid component positioning in anatomic total shoulder arthroplasty (aTSA) using an in-house, point-of-care, 3-dimensionally (3D) printed patient-specific glenoid drill guide vs. standard nonspecific instrumentation. METHODS: This single-center randomized controlled trial included 36 adult patients undergoing primary aTSA. Patients were blinded and randomized 1:1 to either the PSI or the standard aTSA guide groups. The primary endpoint was the accuracy of glenoid component placement (version and inclination), which was determined using a metal-suppression computed tomography scan taken between 6 weeks and 1 year postoperatively. Deviation from the preoperative 3D templating plan was calculated for each patient. Blinded postoperative computed tomography measurements were performed by a fellowship-trained shoulder surgeon and a musculoskeletal radiologist. RESULTS: Nineteen patients were randomized to the patient-specific glenoid drill guide group, and 17 patients were allocated to the standard instrumentation control group. There were no significant differences between the 2 groups for native version (P = .527) or inclination (P = .415). The version correction was similar between the 2 groups (P = .551), and the PSI group was significantly more accurate when correcting version than the control group (P = .042). The PSI group required a significantly greater inclination correction than the control group (P = .002); however, the 2 groups still had similar accuracy when correcting inclination (P = .851). For the PSI group, there was no correlation between the accuracy of component placement and native version, native inclination, or the Walch classification of glenoid wear (P > .05). For the control group, accuracy when correcting version was inversely correlated with native version (P = .033), but accuracy was not correlated with native inclination or the Walch classification of glenoid wear (P > .05). The intraclass correlation coefficient was 0.703 and 0.848 when measuring version and inclination accuracy, respectively. CONCLUSION: When compared with standard instrumentation, the use of in-house, 3D printed, patient-specific glenoid drill guides during aTSA led to more accurate glenoid component version correction and similarly accurate inclination correction. Additional research should examine the influence of proper component position and use of PSI on clinical outcomes.

Predictors of dislocations after reverse shoulder arthroplasty: a study by the ASES complications of RSA multicenter research group.

BACKGROUND: Instability after reverse shoulder arthroplasty (RSA) is one of the most frequent complications and remains a clinical challenge. Current evidence is limited by small sample size, single-center, or single-implant methodologies that limit generalizability. We sought to determine the incidence and patient-related risk factors for dislocation after RSA, using a large, multicenter cohort with varying implants. METHODS: A retrospective, multicenter study was performed involving 15 institutions and 24 American Shoulder and Elbow Surgeons members across the United States. Inclusion criteria consisted of patients undergoing primary or revision RSA between January 2013 and June 2019 with minimum 3-month follow-up. All definitions, inclusion criteria, and collected variables were determined using the Delphi method, an iterative survey process involving all primary investigators requiring at least 75% consensus to be considered a final component of the methodology for each study element. Dislocations were defined as complete loss of articulation between the humeral component and the glenosphere and required radiographic confirmation. Binary logistic regression was performed to determine patient predictors of postoperative dislocation after RSA. RESULTS: We identified 6621 patients who met inclusion criteria with a mean follow-up of 19.4 months (range: 3-84 months). The study population was 40% male with an average age of 71.0 years (range: 23-101 years). The rate of dislocation was 2.1% (n = 138) for the whole cohort, 1.6% (n = 99) for primary RSAs, and 6.5% (n = 39) for revision RSAs (P < .001). Dislocations occurred at a median of 7.0 weeks (interquartile range: 3.0-36.0 weeks) after surgery with 23.0% (n = 32) after a trauma. Patients with a primary diagnosis of glenohumeral osteoarthritis with an intact rotator cuff had an overall lower rate of dislocation than patients with other diagnoses (0.8% vs. 2.5%; P < .001). Patient-related factors independently predictive of dislocation, in order of the magnitude of effect, were a history of postoperative subluxations before radiographically confirmed dislocation (odds ratio [OR]: 19.52, P < .001), primary diagnosis of fracture nonunion (OR: 6.53, P < .001), revision arthroplasty (OR: 5.61, P < .001), primary diagnosis of rotator cuff disease (OR: 2.64, P < .001), male sex (OR: 2.21, P < .001), and no subscapularis repair at surgery (OR: 1.95, P = .001). CONCLUSION: The strongest patient-related factors associated with dislocation were a history of postoperative subluxations and having a primary diagnosis of fracture nonunion. Notably, RSAs for osteoarthritis showed lower rates of dislocations than RSAs for rotator cuff disease. These data can be used to optimize patient counseling before RSA, particularly in male patients undergoing revision RSA.

Relationship Between Arm Path, Ball Velocity, and Elbow Varus Torque in Professional Baseball Pitchers.

Background: Currently, most pitching instructors suggest a shorter arm path-the total distance the arm travels during pitching. Theoretically, this combination allows for better body segment sequencing, a more efficient energy transfer through the kinetic chain, and increased ball velocity, while limiting elbow varus torque. Hypothesis: Shorter arm paths would be associated with increased ball velocity and decreased elbow varus torque. Study Design: Descriptive laboratory study. Methods: A total of 182 professional pitchers threw 8 to 12 fastball pitches while evaluated by 3-dimensional motion capture (480 Hz). The arm path was calculated as the total distance the hand marker traveled during the pitch. The pitch was divided into early, late, and total arm paths. A linear regression model assessed the interpitcher relationship between arm path, elbow varus torque, and ball velocity. A linear mixed-effects model with random intercepts assessed intrapitcher relationships. Results: Interpitcher comparison showed that total arm path weakly correlated with greater elbow varus torque (P = .025). Strong correlations were found between ball velocity and early (R2 = 0.788; P < .001), late (R2 = 0.787; P = .024), and total arm paths (R2 = 0.792; P < .001). Strong positive intrapitcher correlations were found between elbow varus torque and early (R2 = 0.962; P < .001) and total arm path (R2 = 0.964; P < .001). For individual pitchers, there was a large variation in the early (30.1 ± 15.7 cm) and late (21.4 ± 12.1 cm) arm path. For every 30-cm (11.8-inch) increase in early arm path (the mean range for an individual pitcher), there was a 1.29-N (ß = 0.0429) increase in elbow varus torque and a 0.354 m/s (0.79 mph) (ß = 0.0118) increase in ball velocity. Conclusion: A shorter arm path correlated with decreased elbow varus torque and decreased ball velocity in intrapitcher comparisons. Determining the individual mechanics that decrease elbow varus torque may help coaches and trainers correct these patterns. Clinical Significance: A shorter arm path during the pitch can decrease elbow varus torque, which limits the load on the medial elbow but also has a detrimental effect on ball velocity. An improved understanding of the impact of shortening arm paths on stresses on the throwing arm may help minimize injury risk.

Costs of shoulder and elbow procedures are significantly reduced in ambulatory surgery centers compared to hospital outpatient departments.

BACKGROUND: Recent literature has shown the advantages of outpatient surgery for many shoulder and elbow procedures, including cost savings with equivalent safety in appropriately selected patients. Two common settings for outpatient surgeries are ambulatory surgery centers (ASCs), which function as independent financial and administrative entities, or hospital outpatient departments (HOPDs), which are owned and operated by hospital systems. The purpose of this study was to compare shoulder and elbow surgery costs between ASCs and HOPDs. METHODS: Publicly available data from 2022 provided by the Centers for Medicare & Medicaid Services (CMS) was accessed via the Medicare Procedure Price Lookup Tool. Current Procedural Terminology (CPT) codes were used to identify shoulder and elbow procedures approved for the outpatient setting by CMS. Procedures were grouped into arthroscopy, fracture, or miscellaneous. Total costs, facility fees, Medicare payments, patient payment (costs not covered by Medicare), and surgeon's fees were extracted. Descriptive statistics were used to calculate means and standard deviations. Cost differences were analyzed using Mann-Whitney U tests. RESULTS: Fifty-seven CPT codes were identified. Arthroscopy procedures (n = 16) at ASCs had significantly lower total costs ($2667 ± $989 vs. $4899 ± $1917; P = .009), facility fees ($1974 ± $819 vs. $4206 ± $1753; P = .008), Medicare payments ($2133 ± $791 vs. $3919 ± $1534; P = .009), and patient payments ($533 ± $198 vs. $979 ± $383; P = .009) compared with HOPDs. Fracture procedures (n = 10) at ASCs had lower total costs ($7680 ± $3123 vs. $11,335 ± $3830; P = .049), facility fees ($6851 ± $3033 vs. $10,507 ± $3733; P = .047), and Medicare payments ($6143 ± $2499 vs. $9724 ± $3676; P = .049) compared with HOPDs, although patient payments were not significantly different ($1535 ± $625 vs. $1610 ± $160; P = .449). Miscellaneous procedures (n = 31) at ASCs had lower total costs ($4202 ± $2234 vs. $6985 ± $2917; P < .001), facility fees ($3348 ± $2059 vs. $6132 ± $2736; P < .001), Medicare payments ($3361 ± $1787 vs. $5675 ± $2635; P < .001), and patient payments ($840 ± $447 vs. $1309 ± $350; P < .001) compared with HOPDs. The combined cohort (n = 57) at ASCs had lower total costs ($4381 ± $2703 vs. $7163 ± $3534; P < .001), facility fees ($3577 ± $2570 vs. $6539.1 ± $3391; P < .001), Medicare payments ($3504 ± $2162 vs. $5892 ± $3206; P < .001), and patient payments ($875 ± $540 vs. $1269 ± $393; P < .001) compared with HOPDs. CONCLUSION: Shoulder and elbow procedures performed at HOPDs for Medicare recipients were found to have average total cost increase of 164% compared with those performed at ASCs (184% savings for arthroscopy, 148% for fracture, and 166% for miscellaneous). ASC use conferred lower facility fees, patient payments, and Medicare payments. Policy efforts to incentivize migration of surgeries to ASCs may translate into substantial health care cost savings.

Risk factors of acromial and scapular spine stress fractures differ by indication: a study by the ASES Complications of Reverse Shoulder Arthroplasty Multicenter Research Group.

BACKGROUND: Both patient and implant related variables have been implicated in the incidence of acromial (ASF) and scapular spine fractures (SSF) following reverse shoulder arthroplasty (RSA); however, previous studies have not characterized nor differentiated risk profiles for varying indications including primary glenohumeral arthritis with intact rotator cuff (GHOA), rotator cuff arthropathy (CTA), and massive irreparable rotator cuff tear (MCT). The purpose of this study was to determine patient factors predictive of cumulative ASF/SSF risk for varying preoperative diagnosis and rotator cuff status. METHODS: Patients consecutively receiving RSA between January 2013 and June 2019 from 15 institutions comprising 24 members of the American Shoulder and Elbow Surgeons (ASES) with primary, preoperative diagnoses of GHOA, CTA and MCT were included for study. Inclusion criteria, definitions, and inclusion of patient factors in a multivariate model to predict cumulative risk of ASF/SSF were determined through an iterative Delphi process. The CTA and MCT groups were combined for analysis. Consensus was defined as greater than 75% agreement amongst contributors. Only ASF/SSF confirmed by clinical and radiographic correlation were included for analysis. RESULTS: Our study cohort included 4764 patients with preoperative diagnoses of GHOA, CTA, or MCT with minimum follow-up of 3 months (range: 3-84). The incidence of cumulative stress fracture was 4.1% (n = 196). The incidence of stress fracture in the GHOA cohort was 2.1% (n = 34/1637) compared to 5.2% (n = 162/3127) (P < .001) in the CTA/MCT cohort. Presence of inflammatory arthritis (odds ratio [OR] 2.90, 95% confidence interval [CI] 1.08-7.78; P = .035) was the sole predictive factor of stress fractures in GHOA, compared with inflammatory arthritis (OR 1.86, 95% CI 1.19-2.89; P = .016), female sex (OR 1.81, 95% CI 1.20-2.72; P = .007), and osteoporosis (OR 1.56, 95% CI 1.02-2.37; P = .003) in the CTA/MCT cohort. CONCLUSION: Preoperative diagnosis of GHOA has a different risk profile for developing stress fractures after RSA than patients with CTA/MCT. Though rotator cuff integrity is likely protective against ASF/SSF, approximately 1/46 patients receiving RSA with primary GHOA will have this complication, primarily influenced by a history of inflammatory arthritis. Understanding risk profiles of patients undergoing RSA by varying diagnosis is important in counseling, expectation management, and treatment by surgeons.

Management of Glenoid Bone Loss in Primary Reverse Total Shoulder Arthroplasty.

PURPOSE OF REVIEW: Glenoid bone loss presents distinct challenges in reverse total shoulder arthroplasty (rTSA) which, if unaddressed, can cause complications including poor outcomes and early implant failure. The purpose of this review is to discuss the etiology, evaluation, and management strategies of glenoid bone loss in primary rTSA. RECENT FINDINGS: Three-dimensional computed tomography (3D CT) imaging and preoperative planning software have revolutionized the understanding of complex glenoid deformity and wear patterns from bone loss. With this knowledge, a detailed preoperative plan can be created and implemented for a more optimal management strategy. When appropriately indicated, deformity correction techniques with biologic or metal augmentation are successful in addressing the glenoid bone deficiency, creating optimal implant position, and thus providing stable baseplate fixation and improving outcomes. Thorough evaluation and characterization of the degree of glenoid deformity with 3D CT imaging is necessary prior to treatment with rTSA. Eccentric reaming, bone grafting, and augmented glenoid components have shown promising results in correcting glenoid deformity due to bone loss, but long-term outcomes are currently unknown.

Minimal inter-surgeon agreement on the diagnosis of pseudoparalysis in patients with massive rotator cuff tears.

BACKGROUND: Pseudoparalysis is commonly used to describe patients with severe loss of active elevation associated with advanced rotator cuff disease, but its definition in the literature has been variable. This study aimed to determine how 15 expert shoulder surgeons use the term "pseudoparalysis" when presented with clinical cases and assess clinical agreement on the diagnosis of pseudoparalysis. METHODS: Fifteen expert shoulder surgeons were surveyed regarding 18 patients with magnetic resonance imaging-diagnosed massive rotator cuff tears, restricted active range of motion (ROM), full passive ROM, and without advanced rotator cuff arthropathy (Hamada grade <3). The survey included 18 patient vignettes with key clinical details and a deidentified video demonstrating the physical examination of the patient. For all patients, surgeons were instructed to assume that the patient has a full passive ROM. An anteroposterior radiograph and T2 sequences of the patient's coronal, axial, and sagittal magnetic resonance imaging were also provided. After each case, the surgeons were asked: (1) does the patient have pseudoparalysis, and (2) if so, how severe it is. At the end of the patient vignettes, surgeons were asked to define pseudoparalysis using a checklist with predefined options. Surgeons were also asked if there was a difference between the term pseudoparalysis and pseudoparesis. Fleiss' kappa (κ) correlation coefficient was used to determine intersurgeon agreement. RESULTS: There was minimal inter-rater agreement on the diagnosis of pseudoparalysis (κ = 0.360) and no agreement on describing the severity of pseudoparalysis (κ = -0.057). Although 80% of surgeons stated that an active glenohumeral elevation less than 90° was a diagnostic feature of pseudoparalysis, there was disagreement on the remaining criteria, leading to no agreement on a set of universal criteria that defines pseudoparalysis. A total of 67% included maintained full passive elevation, 33% included the absence of pain, 67% included elevation causing anterosuperior escape, and 27% included an additional unlisted factor. There was minimal agreement among the 15 surgeons on the diagnostic criteria of pseudoparalysis (κ = 0.092). Finally, 7 surgeons stated that pseudoparalysis and pseudoparesis are identical, whereas 8 surgeons stated that they are 2 different clinical diagnoses. CONCLUSION: Among this panel of expert shoulder surgeons, there was a lack of consensus on the definition of pseudoparalysis and minimal agreement on the diagnosis of pseudoparalysis based on clinical scenarios. In addition, half the surgeons believed that pseudoparalysis and pseudoparesis are identical, whereas the other half believed that they represent 2 separate clinical entities. A standardized definition of pseudoparalysis would be of value to facilitate communication and research efforts.

Rotator cuff repair: what questions are patients asking online and where are they getting their answers?

BACKGROUND: This study analyzed questions searched by rotator cuff patients and determined types and quality of websites providing information. METHODS: Three strings related to rotator cuff repair were explored by Google Search. Result pages were collected under the "People also ask" function for frequent questions and associated webpages. Questions were categorized using Rothwell classification and topical subcategorization. Webpages were evaluated by Journal of the American Medical Association (JAMA) benchmark criteria for source quality. RESULTS: One hundred twenty "People also ask" questions were collected with associated webpages. Using the Rothwell classification of questions, queries were organized into fact (41.7%), value (31.7%), and policy (26.7%). The most common webpage categories were academic (28.3%) and medical practice (27.5%). The most common question subcategories were timeline of recovery (21.7%), indications/ management (21.7%), and pain (18.3%). Average JAMA score for all 120 webpages was 1.50. Journal articles had the highest average JAMA score (3.77), while commercial websites had the lowest JAMA score (0.91). The most commonly suggested question for rotator cuff repair/ surgery was, "Is rotator cuff surgery worth having?," while the most commonly suggested question for rotator cuff repair pain was, "What happens if a rotator cuff is not repaired?" CONCLUSIONS: The most commonly asked questions pertaining to rotator cuff repair evaluate management options and relate to timeline of recovery and pain management. Most information is provided by medical practice, academic, and medical information websites, which have highly variable reliability. By understanding questions their patients search online, surgeons can tailor preoperative education to patient concerns and improve postoperative outcomes.

Internet search analytics for shoulder arthroplasty: what questions are patients asking?

BACKGROUND: Common questions about shoulder arthroplasty (SA) searched online by patients and the quality of this content are unknown. The purpose of this study is to uncover questions SA patients search online and determine types and quality of webpages encountered. METHODS: The "People also ask" section of Google Search was queried to return 900 questions and associated webpages for general, anatomic, and reverse SA. Questions and webpages were categorized using the Rothwell classification of questions and assessed for quality using the Journal of the American Medical Association (JAMA) benchmark criteria. RESULTS: According to Rothwell classification, the composition of questions was fact (54.0%), value (24.7%), and policy (21.3%). The most common webpage categories were medical practice (24.6%), academic (23.2%), and medical information sites (14.4%). Journal articles represented 8.9% of results. The average JAMA score for all webpages was 1.69. Journals had the highest average JAMA score (3.91), while medical practice sites had the lowest (0.89). The most common question was, "How long does it take to recover from shoulder replacement?" CONCLUSIONS: The most common questions SA patients ask online involve specific postoperative activities and the timeline of recovery. Most information is from low-quality, non-peer-reviewed websites, highlighting the need for improvement in online resources. By understanding the questions patients are asking online, surgeons can tailor preoperative education to common patient concerns and improve postoperative outcomes.

A validated preoperative risk prediction tool for extended inpatient length of stay following anatomic or reverse total shoulder arthroplasty.

BACKGROUND: Recent work has shown inpatient length of stay (LOS) following shoulder arthroplasty to hold the second strongest association with overall cost (after implant cost itself). In particular, a preoperative understanding for the patients at risk of extended inpatient stays (≥3 days) can allow for counseling, optimization, and anticipating postoperative adverse events. METHODS: A multicenter retrospective review was performed of 5410 anatomic (52%) and reverse (48%) total shoulder arthroplasties done at 2 large, tertiary referral health systems. The primary outcome was extended inpatient LOS of at least 3 days, and over 40 preoperative sociodemographic and comorbidity factors were tested for their predictive ability in a multivariable logistic regression model based on the patient cohort from institution 1 (derivation, N = 1773). External validation was performed using the patient cohort from institution 2 (validation, N = 3637), including area under the receiver operator characteristic curve (AUC), sensitivity, specificity, and positive and negative predictive values. RESULTS: A total of 814 patients, including 318 patients (18%) in the derivation cohort and 496 patients (14%) in the validation cohort, experienced an extended inpatient LOS of at least 3 days. Four hundred forty-five (55%) were discharged to a skilled nursing or rehabilitation facility. Following parameter selection, a multivariable logistic regression model based on the derivation cohort (institution 1) demonstrated excellent preliminary accuracy (AUC: 0.826), with minimal decrease in accuracy under external validation when tested against the patients from institution 2 (AUC: 0.816). The predictive model was composed of only preoperative factors, in descending predictive importance as follows: age, marital status, fracture case, ASA (American Society of Anesthesiologists) score, paralysis, electrolyte disorder, body mass index, gender, neurologic disease, coagulation deficiency, diabetes, chronic pulmonary disease, peripheral vascular disease, alcohol dependence, psychoses, smoking status, and revision case. CONCLUSION: A freely-available, preoperative online clinical decision tool for extended inpatient LOS (≥ 3 days) after shoulder arthroplasty reaches excellent predictive accuracy under external validation. As a result, this tool merits consideration for clinical implementation, as many risk factors are potentially modifiable as part of a preoperative optimization strategy.

Activation of cannabinoid-2 receptor protects against Pseudomonas aeruginosa induced acute lung injury and inflammation.

BACKGROUND: Bacterial pneumonia is a major risk factor for acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Pseudomonas aeruginosa (PA), an opportunistic pathogen with an increasing resistance acquired against multiple drugs, is one of the main causative agents of ALI and ARDS in diverse clinical settings. Given the anti-inflammatory role of the cannabinoid-2 receptor (CB2R), the effect of CB2R activation in the regulation of PA-induced ALI and inflammation was tested in a mouse model as an alternative to conventional antibiotic therapy. METHODS: In order to activate CB2R, a selective synthetic agonist, JWH133, was administered intraperitoneally (i.p.) to C57BL/6J mice. Furthermore, SR144528 (a selective CB2R antagonist) was administered in combination with JWH133 to test the specificity of the CB2R-mediated effect. PA was administered intratracheally (i.t.) for induction of pneumonia in mice. At 24 h after PA exposure, lung mechanics were measured using the FlexiVent system. The total cell number, protein content, and neutrophil population in the bronchoalveolar lavage fluid (BALF) were determined. The bacterial load in the whole lung was also measured. Lung injury was evaluated by histological examination and PA-induced inflammation was assessed by measuring the levels of BALF cytokines and chemokines. Neutrophil activation (examined by immunofluorescence and immunoblot) and PA-induced inflammatory signaling (analyzed by immunoblot) were also studied. RESULTS: CB2R activation by JWH133 was found to significantly reduce PA-induced ALI and the bacterial burden. CB2R activation also suppressed the PA-induced increase in immune cell infiltration, neutrophil population, and inflammatory cytokines. These effects were abrogated by a CB2R antagonist, SR144528, further confirming the specificity of the CB2R-mediated effects. CB2R-knock out (CB2RKO) mice had a significantly higher level of PA-induced inflammation as compared to that in WT mice. CB2R activation diminished the excess activation of neutrophils, whereas mice lacking CB2R had elevated neutrophil activation. Pharmacological activation of CB2R significantly reduced the PA-induced NF-κB and NLRP3 inflammasome activation, whereas CB2KO mice had elevated NLRP3 inflammasome. CONCLUSION: Our findings indicate that CB2R activation ameliorates PA-induced lung injury and inflammation, thus paving the path for new therapeutic avenues against PA pneumonia.

Influence of Pelvic Rotation on Lower Extremity Kinematics, Elbow Varus Torque, and Ball Velocity in Professional Baseball Pitchers.

Background: Early pelvic rotation has been associated with decreased throwing arm kinetics in college baseball pitchers, though professional pitchers have yet to be examined. Purpose: To investigate the effect of pelvic rotation on trunk, pelvis and lower extremity kinematics, as well as throwing arm kinetics and pitch velocity in professional baseball pitchers. Study Design: Descriptive laboratory study. Methods: Data were analyzed for 157 professional baseball pitchers throwing fastballs using 3-dimensional motion capture (480 Hz). Pitchers were divided into an open pelvis (rotated toward target; n = 78) and a closed pelvis (n = 79) group based on pelvic rotation at foot contact. Variables of interest were compared between the groups using t tests and 2-way analysis of variance, while Spearman correlation was used to measure relationships between the variables of interest. Results: Pitchers in the open group had a longer stride length (81% ± 5% vs 77% ± 5% body height; P < .01, d = 0.74), greater lead knee flexion (49° ± 6° vs 47° ± 10°; P = .043, d = 0.33), faster peak knee extension velocity (424°/s ± 158°/s vs 325°/s ± 142 °/s; P < .01, d = 0.66), and faster ball velocity (39.1 ± 1.7 m/s vs 38.4 ± 2.1 m/s; P = .029, d = 0.35) compared with those in the closed group. There was no significant difference in elbow varus torque between the 2 groups (open: 87.8 ± 14.7 N·m, closed: 90.5 ± 17.2 N·m; P = .311). There were moderate negative relationships between pelvic rotation at foot contact and stride length (r S = -0.385, P < .001), lead knee extension (r S = -0.429, P < .001), and peak lead knee extension velocity (r S = -0.359, P < .001). Conclusion: Professional pitchers who landed with an open pelvis demonstrated longer stride length, greater lead knee extension, faster lead knee velocity, and faster ball velocity compared with pitchers with a closed pelvis at foot contact. This increase in segment velocities and ball velocity was not associated with an increase in elbow varus torque and displays a potentially efficient method in which pitchers can increase ball velocity without an increase in elbow varus torque. Clinical Relevance: Instructing pitchers to rotate their pelvis toward the target at foot contact may allow pitchers to transfer momentum up the kinetic chain more efficiently, while producing greater ball velocity and limiting the torque sustained at the elbow.

Travel distance does not affect outcomes after total shoulder arthroplasty.

Background: The purpose of this investigation was to determine the effect of travel distance on achieving the minimal clinically important difference (MCID) on all three commonly used patient-reported outcome measures (PROMs) for the shoulder more than 1 year following total shoulder arthroplasty (TSA). Methods: Patients undergoing reverse or anatomic TSA at a high-volume tertiary referral center between September 2016 and August 2018 were retrospectively reviewed. Patients were divided into 2 groups: driving distance of >50 miles from the location of surgery (referral group) and driving distance of <50 miles (local group). Scores on preoperative and postoperative PROMs, including American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation (SANE) score, and Constant Score (CS) at minimum 1-year follow-up were assessed. Chi-square analysis was used to analyze the achievement of MCID on any PROM or a combination of PROMs. Logistic regression was performed to determine whether travel distance and other variables of interest had an effect on achieving MCID on all three PROMs. Results: A total of 214 patients with minimum 1-year follow-up were included in the final analysis. Of these, 165 patients (77.1%) traveled <50 miles to their orthopedic provider at the time of surgery. The local group demonstrated significantly inferior preoperative SANE scores (P < .001) and significantly higher postoperative ASES scores (P = .001). A total of 166 (77%) patients achieved all three MCIDs postoperatively. There was no significant difference between distance groups for achievement of all MCIDs (P = .328). On multivariable regression, body mass index > 30 (odds ratio [OR], 5.78; 95% confidence interval [CI], 1.53-30.28), worker's compensation status (OR, 16.78; 95% CI, 2.34-161.39), and higher preoperative ASES score (OR, 1.04; 95% CI, 1.01-1.07) were associated with an increased risk of failure to achieve all MCIDs (P < .05). Age, adjusted gross income, private insurance, and travel distance were not significantly associated with failure to achieve all MCIDs. Conclusions: After controlling for age, sex, and adjusted gross income, distance traveled to a high-volume referral center did not have an effect on achieving the MCID on all three commonly used PROMs for the shoulder at least 1 year after undergoing TSA. Elevated body mass index, worker's compensation status, and higher preoperative ASES score were associated with an increased risk of failure to achieve all MCIDs after TSA.

Roles of each leg in impulse generation in professional baseball pitchers: preliminary findings uncover the contribution of the back leg towards whole-body rotation.

This study examined the roles of each leg in generating linear and angular impulses during baseball pitching. Professional pitchers (n = 4) pitched from a force plate instrumented mound, and 6-11 successful fastball pitches were used for analyses. We compared linear and angular impulses across the back and front legs. Linear and angular impulses were calculated from ground reaction force (GRF) and moment about each global axis passing through the centre of mass (COM), respectively. Additionally, we analysed measures that control the moment: (1) GRF magnitude, (2) magnitude of the position vector from COM to the centre of pressure and (3) the angle between (1) and (2). We found that the back leg generated forward linear impulse and the front leg generated backward linear impulse for all pitchers. Surprisingly, we found that the back leg generated significantly greater positive angular impulse about a global leftward axis (from the mound towards first base) than did the front leg in all four pitchers. Furthermore, the back leg's moment about the leftward axis became positive after the magnitude of forward GRF decreased from its maximum, suggesting that the back leg's role transitioned from generating forward linear momentum to angular momentum.

The fifty most cited publications in shoulder arthroplasty research.

Introduction: Frequency of citation provides one quantitative metric of the impact that an article has on a given field. The purpose of this study was to evaluate characteristics of the 50 most cited publications on shoulder arthroplasty. Methods: The Web of Science database was used to determine the 50 most frequently cited shoulder arthroplasty articles. Articles were evaluated for several factors including type of arthroplasty, citation frequency and rate, source journal, country of origin, study type, and level of evidence. Results: The most common countries of origin were the United States (60%) followed by France (24%) and Switzerland (6%). A total of 27 (54%) articles included anatomic total shoulder arthroplasty (TSA), 18 (36%) included reverse total shoulder arthroplasty (RTSA), and 15 (30%) included hemiarthroplasty. Articles including RTSA had the greatest number of citations compared to those on TSA (p = 0.037) and hemiarthroplasty (p = 0.035). Citations per year were also greatest with RTSA compared to TSA and hemiarthroplasty (p ≤ 0.001). Discussion: This citation analysis includes many of the landmark studies that shaped, and continue to impact, the field of shoulder arthroplasty. This list provides a group of influential articles that provide a foundation for future research in shoulder arthroplasty.

Do total shoulder arthroplasty implants corrode?

BACKGROUND: Total shoulder arthroplasty (TSA) has become the gold-standard treatment to relieve joint pain and disability in patients with glenohumeral osteoarthritis who do not respond to conservative treatment. An adverse reaction to metal debris released due to fretting corrosion has been a major concern in total hip arthroplasty. To date, it is unclear how frequently implant corrosion occurs in TSA and whether it is a cause of implant failure. This study aimed to characterize and quantify corrosion and fretting damage in a single anatomic TSA design and to compare the outcomes to the established outcomes of total hip arthroplasty. METHODS: We analyzed 21 surgically retrieved anatomic TSAs of the same design (Tornier Aequalis Pressfit). The retrieved components were microscopically examined for taper corrosion, and taper damage was scored. Head and stem taper damage was quantitatively measured with a non-contact optical coordinate-measuring machine. In selected cases, damage was further characterized at high magnifications using scanning electron microscopy. Energy-dispersive x-ray spectroscopy and metallographic evaluations were performed to determine underlying alloy microstructure and composition. Comparisons between groups with different damage features were performed with independent-samples t tests; Mann-Whitney tests and multivariate linear regression were conducted to correlate damage with patient factors. The level of statistical significance was set at P < .05. RESULTS: The average material loss for head and stem tapers was 0.007 mm3 and 0.001 mm3, respectively. Material loss was not correlated with sex, age, previous implant, or time in situ (P > .05). We observed greater volume loss in head tapers compared with stem tapers (P = .002). Implants with evidence of column damage had larger volumetric material loss than those without such evidence (P = .003). Column damage aligned with segregation bands within the alloy (preferential corrosion sites). The average angular mismatch was 0.03° (standard deviation, 0.0668°), with negative values indicating distal engagement and positive values indicating proximal engagement. Implants with proximal engagement were significantly more likely to have column damage than those with distal engagement (P = .030). DISCUSSION: This study has shown not only that the metal components of TSA implants can corrode but also that the risk of corrosion can be reduced by (1) eliminating preferential corrosion sites and (2) ensuring distal engagement to prevent fluid infiltration into the modular junction.

Magnetic Resonance Imaging Findings of the Asymptomatic Shoulder May Impact Performance, Not Future Injury List Placement in Major League Baseball Pitchers.

Purpose: To evaluate preseason shoulder magnetic resonance images (MRIs) obtained from pitchers entering either major or minor league baseball (MLB) and correlate findings with subsequent injury, operative repair, and placement on the injured list (IL). Methods: Preseason-MRI of the throwing shoulders of professional-level baseball pitchers, taken during routine evaluations at a single organization (2004-2017) were retrospectively reviewed. Publicly available databases were queried to exclude pitchers with known injuries prior to pre-signing imaging. Three blinded reviewers reviewed all MRI scans independently to evaluate for the presence of abnormalities in the rotator cuff (RTC), labrum, capsule, long-head of the biceps tendon (LHBT), and humeral head. Binary imaging findings were correlated to future placement on the IL for subsequent shoulder complaints. Bivariate statistics using Student's t-tests and Fisher exact tests (both α = .05) were used in this study. Results: A total of 38 asymptomatic pitchers with shoulder MRIs were included. Pitchers had a mean (±SD) age of 28.2 ± 4.9 and had pitched an average of 119.6 ± 143.8 career games. Pitchers with partial articular-sided RTC tears (P = .04) or intra-articular BT hyperintensity (P = .04) on preseason MRI demonstrated an association with the need for future surgery. Pitchers with evidence of labral heterogeneity demonstrated greater total career pitch counts (10,034.1 vs 2,465.3; P = .04). Evidence of a posterior-superior humeral cyst was associated with decreased strikeouts per 9 innings (6.1 vs 8.0; P = .039) and total strikeout percentage (16.1% vs 23.2%; P = .04). Conclusion: Although there was a significant difference in the percent of various radiographic findings between the injured and healthy cohort, no MRI findings were predictive of future IL placement or duration of placement. The presence of a posterior superior humeral cyst was associated with decreased strikeout rates at 2 and 3 years, the presence of a labral tear was associated with decreased earned run average (ERA) at 3 years and decreased career strikeout percentages, and increased capsular signal was associated with decreased 5-year ERA. Level of Evidence: Level IV, retrospective study.

The Definition of Periprosthetic Osteolysis in Shoulder Arthroplasty: A Systematic Review of Grading Schemes and Criteria.

BACKGROUND: Periprosthetic osteolysis is a known complication after shoulder arthroplasty that may lead to implant loosening and revision surgery. To date, there is no consensus in the shoulder arthroplasty literature regarding the definition of osteolysis or the grading criteria, thus making it difficult to quantify and compare outcomes involving this complication. The purpose of this study was to perform a systematic review of the literature to assess how periprosthetic osteolysis in shoulder arthroplasty is defined and evaluated radiographically. METHODS: A systematic review of MEDLINE, Scopus, Cochrane, and CINAHL was performed in August 2021 for studies that provided a definition and/or grading criteria for osteolysis in shoulder arthroplasty. Only studies with a minimum of 2 years of radiographic follow-up were included. RESULTS: Thirty-four articles met the inclusion criteria. After consolidating studies by the same primary author that included the same grading criteria, 29 studies were examined for their definition and grading criteria for osteolysis. Of these, 19 (65.5%) evaluated osteolysis surrounding the glenoid and 18 (62.1%) evaluated osteolysis surrounding the humerus. There was considerable heterogeneity in the systems used to grade periprosthetic osteolysis surrounding the glenoid, whereas humeral periprosthetic osteolysis was often categorized via visualization into binary or categorical groups (e.g., presence versus absence; mild, moderate, or severe; partial versus complete). Four studies (13.8%) provided novel measurements for assessing either glenoid or humeral osteolysis. CONCLUSIONS: Considerable heterogeneity exists in the assessment and grading of periprosthetic osteolysis in shoulder arthroplasty. The most common grading systems were binary and used qualitative visual interpretation, making them relatively subjective and prone to bias. Quantitative measurements of osteolysis were infrequently utilized. A standardized method of assessing osteolysis would be of value to facilitate communication and research efforts.

Does native glenoid anatomy predispose to shoulder instability? An MRI analysis.

BACKGROUND: It is unclear if native glenohumeral anatomic features predispose young patients to instability and if such anatomic risk factors differ between males and females. The purpose of this study was to compare glenoid and humeral head dimensions between patients with a documented instability event without bone loss to matched controls and to evaluate for sex-based differences across measurements. The authors hypothesized that a smaller glenoid width and glenoid surface area would be significant risk factors for instability, whereas humeral head width would not. METHODS: A prospectively maintained database was queried for patients aged <21 years who underwent magnetic resonance imaging (MRI) for shoulder instability. Patients with prior shoulder surgery, bony Bankart, or glenoid or humeral bone loss were excluded. Patients were matched by sex and age to control patients who had no history of shoulder instability. Two blinded independent raters measured glenoid height, glenoid width, and humeral head width on sagittal MRI. Glenoid surface area, glenoid index (ratio of glenoid height to width), and glenohumeral mismatch ratio (ratio of humeral head width to glenoid width) were calculated. RESULTS: A total of 107 instability patients and 107 controls were included (150 males and 64 females). Among the entire cohort, there were no differences in glenoid height, glenoid width, glenoid surface area, humeral head width, or glenoid index between patients with instability and controls. Overall, those with instability had a greater glenohumeral mismatch ratio (P = .029) compared with controls. When stratified by sex, female controls and instability patients showed no differences in any of the glenoid or humerus dimensions. However, males with instability had a smaller glenoid width by 3.5% (P = .017), smaller glenoid surface area by 5.2% (P = .015), and a greater glenohumeral mismatch ratio (P = .027) compared with controls. CONCLUSION: Compared with controls, males with instability were found to have smaller glenoid width and surface area, and a glenoid width that was proportionally smaller relative to humeral width. In contrast, bony glenohumeral morphology did not appear to be a significant risk factor for instability among females. These sex-based differences suggest that anatomic factors may influence risk of instability for male and female patients differently.

Trends in outpatient versus inpatient total shoulder arthroplasty over time.

BACKGROUND: The purpose of this study was to investigate the safety of outpatient and inpatient total shoulder arthroplasty (TSA) and to investigate changes over time. METHODS: Patients undergoing primary TSA during 2006-2019 as part of the American College of Surgeons National Surgical Quality Improvement Program were identified. Patients were divided into an early cohort (2006-2016, 12,401 patients) and a late cohort (2017-2019, 12,845 patients). Outpatient procedures were defined as those discharged on the day of surgery. Patient comorbidities and rate of adverse events within 30 days postoperatively were compared with adjustment for baseline characteristics using standard multivariate regression. RESULTS: There was a significant reduction in complications over time when considering all cases (5.69% in the early cohort vs. 3.67% in the late cohort, adjusted relative risk [RR] = 0.65, 95% confidence interval [CI] = 0.58-0.73, P < .001). The rate of complications decreased over time among inpatients (5.80% vs. 3.90%, adjusted RR = 0.68, 95% CI = 0.60-0.76, P < .001). However, there was no difference in the rate of complications among outpatients over time (1.98% vs. 1.38%, adjusted RR = 0.64, 95% CI = 0.28-1.47, P = .293). There were significantly more complications among inpatients vs. outpatients in both the early and late cohorts (early: 5.80% vs. 1.98%, adjusted RR = 2.57, 95% CI = 1.24-5.34, P = .011, late: 3.90% vs. 1.38%, adjusted RR = 2.28, 95% CI = 1.39-3.74, P = .001). TSA became more common in elderly patients over 70 years of age over time in both the inpatient and outpatient cohorts, whereas fewer young patients (aged 18-59 years) underwent TSA in the late cohorts than in the early cohorts for both the inpatient and outpatient samples (P < .001). CONCLUSION: The overall complication rate of TSA has decreased over time as outpatient TSA has become increasingly common. When contemporary data are examined, the complication rate of outpatient procedures has remained constant over time while that of inpatient procedures decreased, despite the changing demographics of patients undergoing TSA. This indicates that outpatient TSA remains a safe procedure as patient selection criteria have evolved, while the safety of inpatient TSA continues to improve.