Optimizing Visualization in Shoulder Arthroscopy: An Evidence-Based Guide.

Advances in arthroscopy have contributed toward improved understanding and management of diverse pathological conditions in the shoulder. As a result, arthroscopy is often preferred by both patients and surgeons. However, surgery can be complicated by limited visualization. Techniques to improve visualization include patient and portal positioning, mechanical débridement, radiofrequency ablation, epinephrine added to irrigation fluid, tranexamic acid administration, and controlled hypotensive anesthesia. Despite published literature on each, a thorough understanding of the evidence supporting these techniques and adjuvants is essential to interpret the clinical utility of each.

Trends in reported outcomes and patient reported outcome measures (PROMs) in humeral shaft fracture literature: a systematic review.

PURPOSE: With a lack of standardization among outcome measures in fracture literature, cross-study comparisons remain limited. This systematic review aimed to identify trends in outcome measures reported by studies of the treatment of humeral shaft fractures. METHODS: A systematic review was performed of studies reporting clinical outcomes of humeral shaft fractures indexed in PubMed. Extracted data included demographics, fracture characteristics, treatment modalities, outcomes, patient reported outcome measures (PROMs), and journal characteristics. Cochran-Armitage tests and linear regressions were used to identify data trends. Pearson chi-square and Kruskal-Wallis tests were used for comparisons between studies. RESULTS: This review included 197 studies with outcomes of 15,445 humeral shaft fractures. 126 studies reported PROMs and 37 different PROMs were used. The Constant Score was most commonly reported (34% of studies), followed by ASES Score (21%), MEPS (21%), and DASH Score (20%). There was a significant increase in PROM usage over time (p = 0.016) and in articles using three or more PROMs (p = 0.005). The number of PROMs were significantly greater in prospective cohort studies and RCTs (p = 0.012) compared to retrospective cohort studies and case series (p = 0.044 for both). Post-treatment shoulder motion was reported in 43% of studies and 34% reported elbow motion. 86% of studies reported complications as an outcome parameter. Time to union and nonunion rate were published in 69% and 88% of studies, respectively. CONCLUSION: This study identified increasing PROM usage over time and disparities in the reporting of outcomes in humeral shaft fracture literature requiring further validation and standardization of available outcome measures.

Implant-related and medical complications in patients with sarcopenia undergoing total shoulder arthroplasty: A retrospective matched-cohort analysis.

Background: In the continually aging United States population, the number of patients with sarcopenia who undergo shoulder arthroplasty may concomitantly increase. This retrospective cohort study aims to evaluate the rates of short-term implant-related and medical complications following shoulder arthroplasty in patients with and without a recent diagnosis of sarcopenia. Methods: An exact 1:3 matched analysis of 4177 patients was performed using the PearlDiver database. Multivariable logistic regression was used to compare complications, Kaplan-Meier failure analysis was used to compare the cumulative hospital readmission rates. Two-sample T-testing was used to compare the 90-day cost of care. Results: Sarcopenic patients were significantly more likely to experience postoperative shoulder instability (odds ratio (OR) = 2.32, 95% confidence interval (CI), 1.21-4.39) and periprosthetic infection (OR = 3.83, 95% CI, 1.74-8.67) within 1 year of their arthroplasty. Sarcopenic patients were at 25% and 41% greater risk of emergency department presentation and hospital readmission 1-year post-arthroplasty, respectively. Ninty-day total costs were greater among sarcopenics ($16 112.23 vs. 10 679.58, p < 0.001). Conclusion: These results are important for orthopaedic surgeons counselling patients with a low muscle mass on the potential for increased complications after undergoing a total shoulder arthroplasty procedure.

Acute-on-Chronic Axillary Artery Thrombus After Reverse Total Shoulder Arthroplasty for Failed Proximal Humerus Open Reduction and Internal Fixation: A Case Report.

CASE: A 71-year-old woman presented with post-traumatic arthritis 11 months after open reduction and internal fixation for a left proximal humerus fracture (PHF) dislocation. After revision to reverse total shoulder arthroplasty (rTSA), the patient's left upper extremity was found to be avascular. An emergent thrombectomy was performed with restoration of arterial flow after removal of an acute-on-chronic axillary artery thrombus. CONCLUSION: Although rare, as rTSA becomes more common for management of PHF, incidence of associated vascular injuries is likely to rise. Screening methods and clinical vigilance in diagnosis are advised for patients with anterior PHF dislocations and arterial injury risk factors.

Female sex and ipsilateral reoperation risk following mesh-based inguinal hernia repair: a cohort study including 131,626 repairs in adults from an integrated healthcare system over a 10-year period.

PURPOSE: We sought to compare females and males for the risk of reoperation following different inguinal hernia repair approaches (open, laparoscopic, and robotic). METHODS: We conducted a retrospective cohort study including all patients aged ≥ 18 who underwent first inguinal hernia repair with mesh within a US integrated healthcare system (2010-2020). Data were obtained from the system's integrated electronic health record. Multiple Cox proportional-hazards regression was used to evaluate the association between sex and risk for ipsilateral reoperation during follow-up. Analysis was stratified by surgical approach (open, laparoscopic, and robotic). RESULTS: The study cohort was comprised of 110,805 patients who underwent 131,626 inguinal hernia repairs with mesh, 10,079 (7.7%) repairs were in females. After adjustment for confounders, females had a higher risk of reoperation than males following open groin hernia repair (hazard ratio [HR] = 1.98, 95% CI 1.74-2.25), but a lower reoperation risk following laparoscopic repair (HR = 0.70, 95% CI 0.51-0.97). The crude 5-year cumulative reoperation probability following robotic repair was 2.8% in males and no reoperations were observed for females. Of females who had a reoperation, 10.3% (39/378) were for a femoral hernia, while only 0.6% (18/3110) were for femoral hernias in males. CONCLUSION: In a large multi-center cohort of mesh-based inguinal hernia repair patients, we found a higher risk for reoperation in females after an open repair approach compared to males. Lower risk was observed for females through a minimally invasive approach (laparoscopic or robotic) and may be due to the ability to identify an occult femoral hernia through these approaches.

The effect of concurrent cervical spine degenerative disease on the outcome of rotator cuff repair: a national database study.

BACKGROUND: Cervical spine degenerative disease (CSD) can cause shoulder pain, potentially confounding the management of patients with rotator cuff tears. This study aimed to investigate the relationships between CSD and rotator cuff repair (RCR). METHODS: A national administrative database (PearlDiver) was used to study 4 patient cohorts: (1) RCR only (RCRo), (2) RCR with concurrent CSD (RCRC), (3) RCR after a cervical spine procedure (RCRA), and (4) RCR before a cervical spine procedure (RCRB). The outcomes of RCR were compared using multivariable logistic regression, controlling for age, sex, and Elixhauser Comorbidity Index, as well as preoperative opioid utilization in the analysis of opioid use. RESULTS: Between 2010 and 2021, a total of 889,977 patients underwent RCR. Of these patients, 784,230 (88%) underwent RCRo whereas 105,747 (12%) underwent RCRC, of whom 21,585 (2.4%) underwent cervical spine procedures (RCRA in 9670 [1.1%] and RCRB in 11,915 [1.3%]). At 2 years after RCR, compared with RCRo patients, RCRC patients had an increased risk of surgical-site infection (adjusted odds ratio [aOR] = 1.25, P = .0004), deep vein thrombosis (aOR = 1.17, P = .0002), respiratory complications (aOR = 1.19, P = .0164), and ipsilateral shoulder reoperations (débridement [aOR = 1.66, P < .0001], manipulation under anesthesia or arthroscopic lysis of adhesions [aOR = 1.23, P < .0001], distal clavicle excision [aOR = 1.78, P < .0001], subacromial decompression [aOR = 1.72, P < .0001], biceps tenodesis [aOR = 1.76, P < .0001], incision and drainage [aOR = 1.34, P = .0020], synovectomy [aOR = 1.48, P = .0136], conversion to shoulder arthroplasty [aOR = 1.62, P < .0001], revision RCR [aOR = 1.77, P < .0001], and subsequent contralateral RCR [aOR = 1.71, P < .0001]). At 2 years, compared with RCRC patients who did not undergo cervical spine procedures, RCRC patients who underwent cervical spine procedures had an increased risk of incision and drainage (aOR = 1.50, P = .0255), conversion to arthroplasty (aOR = 1.40, P < .0001), and revision RCR (aOR = 1.11, P = .0374), as well as a lower risk of contralateral RCR (aOR = 0.89, P = .0469). The sequence of cervical spine procedures did not affect the risk of shoulder reoperations. At 1 year, the risk of opioid use after RCR was less for RCRA patients compared with RCRB patients (aOR = 1.71 [95% confidence interval, 1.61-1.80; P < .0001] vs. aOR = 2.01 [95% confidence interval, 1.92-2.12; P < .0001]). CONCLUSION: Concurrent CSD has significant detrimental effects on RCR outcomes. Patients with concurrent CSD undergoing cervical spine procedures have a greater risk of ipsilateral shoulder reoperations but a decreased risk of contralateral RCR. The risk of prolonged opioid use was lower if RCR followed a cervical spine procedure. Concurrent CSD must be considered and possibly treated to optimize the outcomes of RCR.

Risk factors for reoperation following inguinal hernia repair: results from a cohort of patients from an integrated healthcare system.

PURPOSE: Inguinal hernia repair is one of the most common operations performed globally. Identification of risk factors that contribute to hernia recurrence following an index inguinal hernia repair, especially those that are modifiable, is of paramount importance. Therefore, we sought to investigate risk factors for reoperation following index inguinal hernia repair. METHODS: 125,133 patients aged ≥ 18 years who underwent their first inguinal hernia repair with mesh within a large US integrated healthcare system were identified for a cohort study (2010-2020). Laparoscopic, robotic, and open procedures were included. The system's integrated electronic health record was used to obtain data on demographics, patient characteristics, surgical characteristics, and reoperations. The association of these characteristics with ipsilateral reoperation during follow-up was modeled using Cox proportional-hazards regression. Risk factors were selected into the final model by stepwise regression with Akaike Information Criteria, which quantifies the amount of information lost if a factor is left out of the model. Factors associated with reoperation with p < 0.05 were considered statistically significant. RESULTS: The cumulative incidence of reoperation at 5-year follow-up was 2.4% (95% CI 2.3-2.5). Increasing age, female gender, increasing body mass index, White race, chronic pulmonary disease, diabetes, drug abuse, peripheral vascular disease, and bilateral procedures all associated with a higher risk for reoperation during follow-up. CONCLUSION: This study identifies several risk factors associated with reoperation following inguinal hernia repair. These risk factors may serve as targets for optimization protocols prior to elective inguinal hernia repair, with the goal of reducing reoperation risk.

Periodic orbits in chaotic systems simulated at low precision.

Non-periodic solutions are an essential property of chaotic dynamical systems. Simulations with deterministic finite-precision numbers, however, always yield orbits that are eventually periodic. With 64-bit double-precision floating-point numbers such periodic orbits are typically negligible due to very long periods. The emerging trend to accelerate simulations with low-precision numbers, such as 16-bit half-precision floats, raises questions on the fidelity of such simulations of chaotic systems. Here, we revisit the 1-variable logistic map and the generalised Bernoulli map with various number formats and precisions: floats, posits and logarithmic fixed-point. Simulations are improved with higher precision but stochastic rounding prevents periodic orbits even at low precision. For larger systems the performance gain from low-precision simulations is often reinvested in higher resolution or complexity, increasing the number of variables. In the Lorenz 1996 system, the period lengths of orbits increase exponentially with the number of variables. Moreover, invariant measures are better approximated with an increased number of variables than with increased precision. Extrapolating to large simulations of natural systems, such as million-variable climate models, periodic orbit lengths are far beyond reach of present-day computers. Such orbits are therefore not expected to be problematic compared to high-precision simulations but the deviation of both from the continuum solution remains unclear.

Mesh-based inguinal hernia repairs in an integrated healthcare system and surgeon and hospital volume: a cohort study of 110,808 patients from over a decade.

PURPOSE: The aim of this study was to describe a cohort of patients who underwent inguinal hernia repair within a United States-based integrated healthcare system (IHS) and evaluate the risk for postoperative events by surgeon and hospital volume within each surgical approach, open, laparoscopic, and robotic. METHODS: Patients aged ≥ 18 years who underwent their first inguinal hernia repair were identified for a cohort study (2010-2020). Average annual surgeon and hospital volume were broken into quartiles with the lowest volume quartile as the reference group. Multiple Cox regression evaluated risk for ipsilateral reoperation following repair by volume. All analyses were stratified by surgical approach (open, laparoscopic, and robotic). RESULTS: 110,808 patients underwent 131,629 inguinal hernia repairs during the study years; procedures were performed by 897 surgeons at 36 hospitals. Most repairs were open (65.4%), followed by laparoscopic (33.5%) and robotic (1.1%). Reoperation rates at 5 and 10 years of follow-up were 2.4% and 3.4%, respectively; rates were similar across surgical groups. In adjusted analysis, surgeons with higher laparoscopic volumes had a lower reoperation risk (27-46 average annual repairs: hazard ratio [HR] = 0.63, 95% confidence interval [CI] 0.53-0.74; ≥ 47 repairs: HR 0.53, 95% CI 0.44-0.64) compared to those in the lowest volume quartile (< 14 average annual repairs). No differences in reoperation rates were observed in reference to surgeon or hospital volume following open or robotic inguinal hernia repair. CONCLUSION: High-volume surgeons may reduce reoperation risk following laparoscopic inguinal hernia repair. We hope to better identify additional risk factors for inguinal hernia repair complications and improve patient outcomes with future studies.

Comparison of Humeral-Head Replacement with Glenoid-Reaming Arthroplasty (Ream and Run) Versus Anatomic Total Shoulder Arthroplasty: A Matched-Cohort Study.

BACKGROUND: Glenoid component failure is a major concern after anatomic total shoulder arthroplasty (aTSA). Ream and run (RnR) is an alternative procedure that may avoid glenoid-related complications. The purpose of this study was to compare outcomes of RnR versus aTSA in younger patients with advanced glenohumeral osteoarthritis. METHODS: This was a retrospective matched-cohort study of 110 patients who underwent aTSA and 57 patients who underwent RnR; patients were <66 years of age and had a minimum of 2 years of follow-up. Propensity matching was performed using 21 preoperative variables. Pre- and postoperative patient-reported outcome measures (PROMs) and health-related quality-of-life (HRQoL) scores, satisfaction with outcome, and revision data were analyzed. Mixed-effects models examined the association of preoperative variables with outcomes. RESULTS: Thirty-nine patient pairs were matched. All patients were male, with a mean age of 58.6 ± 7.3 years and a mean follow-up 4.4 ± 2.3 years. The aTSA cohort had better final Simple Shoulder Test (SST) and American Shoulder and Elbow Surgeons (ASES) scores. However, in the mixed-effects model analysis, arthroplasty type was not associated with outcome. At 2 years postoperatively, a significantly greater percentage of aTSA patients achieved the substantial clinical benefit (SCB) for the ASES (100% versus 79.2%; p = 0.01) and the minimal clinically important difference (MCID) (89.7% versus 75%; p = 0.02) for the visual analog scale (VAS) for pain. At >5-year follow-up, there were no significant differences between the cohorts in the percentage who achieved the MCID, SCB, or patient acceptable symptom state (PASS) for the ASES, SST, and VAS for pain. Three patients underwent revision arthroplasty for pain after RnR, at a mean of 1.9 ± 1.7 years. Two patients underwent revision arthroplasty for glenoid loosening at 9.2 and 14 years after aTSA. CONCLUSIONS: RnR and aTSA had comparable outcomes in most analyses. The greater early revision rate after RnR should focus attention on optimizing patient selection and postoperative management. Revision for glenoid loosening is a concern among younger and active patients. Longer-term study is needed to better understand the relative benefits and disadvantages of these procedures. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Increased Risk of Periprosthetic Fractures and Revision Arthroplasty in Patients Undergoing Shoulder Arthroplasty With a History of Prior Fragility Fractures: A Matched Cohort Analysis.

INTRODUCTION: As rates of anatomic and reverse total shoulder arthroplasty (SA) continue to grow, an increase in the number of osteoporotic patients undergoing SA, including those who have sustained prior fragility fractures, is expected. The purpose of this study was to examine short-term, implant-related complication rates and secondary fragility fractures after SA in patients with and without a history of fragility fractures. METHODS: A propensity score-matched retrospective cohort study was done using the PearlDiver database to characterize the effect of antecedent fragility fractures in short-term complications after SA. Rates of revision SA, periprosthetic fractures, infection, and postoperative fragility fractures were evaluated using multivariate logistic regression analysis. Risks of these complications were also studied in patients with and without preoperative osteoporosis treatment. Statistical significance was set at P < 0.05. RESULTS: A total of 91,212 SA patients were identified, with 13,050 (14.3%) experiencing a fragility fracture within the 3 years before SA. Two years after SA, there were increased odds of periprosthetic fracture (odds ratio [OR] 2.24, 95% confidence interval [CI] 1.68 to 2.99), fragility fracture (OR 9.11, 95% CI 8.43 to 9.85), deep infection (OR 1.68, 95% CI 1.34 to 2.12), and all-cause revision SA (OR 1.68, 95% CI 1.44 to 1.96) within those patients who had experienced a fragility fracture within 3 years before their SA. Patients who were treated for osteoporosis with bisphosphonates and/or vitamin D supplementation before their SA had similar rates of postoperative periprosthetic fractures, fragility fractures, and all-cause revision SA to those who did not receive pharmacologic treatment. CONCLUSION: Sustaining a fragility fracture before SA portends substantial postoperative risk of periprosthetic fractures, infection, subsequent fragility fractures, and all-cause revision SA at the 2-year postoperative period. Pharmacotherapy did not markedly decrease the rate of these complications. These results are important for surgeons counseling patients who have experienced prior fragility fractures on the risks of SA.

Short-term clinical and radiographic outcomes in patients treated with a modern intramedullary nailing system for 2-part proximal humerus fractures.

OBJECTIVES: The optimal surgical treatment of displaced proximal humerus fractures (PHFs) remains controversial. There are advocates for both open reduction and internal fixation with plate and screws (ORIF) and intramedullary nailing (IMN). The purpose this study was to evaluate the early-term clinical and radiographic outcomes of IMN for isolated, displaced 2-part surgical neck PHFs using a modern, straight nail system and to determine the effect of preoperative patient and fracture characteristics on outcome. METHODS: This was a case series of 23 patients with displaced 2-part surgical neck PHFs who were treated with ORIF using a straight IMN with minimum follow-up of 1 year (mean 2.5 years [range, 1.1-4.6]). Patients were identified retrospectively and contacted for measurement of active range of motion (AROM) and patient reported outcome measures (PROMs) including the American Shoulder and Elbow Surgeons (ASES) score, Oxford Shoulder Score (OSS), and Single Assessment Numeric Evaluation (SANE), EuroQol-5D (EQ-5D), and Visual Analog Scale Pain score (VAS Pain). Plain radiographs were evaluated to assess the quality of the reduction and failure of fixation. Complications and reoperations were identified. RESULTS: Reduction was anatomic in 12 (52%) patients, acceptable in 9 (39%), and 2 (9%) were malreduced. There were no differences in reduction quality based on sex (p = 0.37), age at surgery (p = 0.68), calcar comminution (p = 0.68), number of screws in the head (p = 0.99), or medial hinge disruption (p = 0.06). At final follow-up, the mean ASES score was 92 ± 10, OSS was 45 ± 4, SANE was 93 ± 7, EQ-5D of 0.85 ± 0.17, and VAS Pain was 0 ± 1. The mean active forward flexion was 143° ± 16°, active external rotation was 68° ± 20°, and internal rotation was T11 ± 4 vertebrae. Two (9%) patients underwent reoperation and 2 (9%) patients experienced clinical failure not requiring reoperation. CONCLUSIONS: Straight IMN is a reliable treatment for displaced 2-part surgical neck PHFs with excellent radiographic and clinical outcomes in early follow-up. The implant facilitated anatomic or acceptable alignment of the fracture in the vast majority of patients.

Longitudinal transcriptome analysis of cattle infected with Theileria parva.

The apicomplexan cattle parasite Theileria parva is a major barrier to improving the livelihoods of smallholder farmers in Africa, killing over one million cattle on the continent each year. Although exotic breeds not native to Africa are highly susceptible to the disease, previous studies have illustrated that such breeds often show innate tolerance to infection by the parasite. The mechanisms underlying this tolerance remain largely unclear. To better understand the host response to T. parva infection we characterised the transcriptional response over 15 days in tolerant and susceptible cattle (n = 29) naturally exposed to the parasite. We identify key genes and pathways activated in response to infection as well as, importantly, several genes differentially expressed between the animals that ultimately survived or succumbed to infection. These include genes linked to key cell proliferation and infection pathways. Furthermore, we identify response expression quantitative trait loci containing genetic variants whose impact on the expression level of nearby genes changes in response to the infection. These therefore provide an indication of the genetic basis of differential host responses. Together these results provide a comprehensive analysis of the host transcriptional response to this under-studied pathogen, providing clues as to the mechanisms underlying natural tolerance to the disease.

Early outcome of humeral head replacement with glenoid reaming arthroplasty (Ream and Run) for treatment of advanced glenohumeral osteoarthritis.

INTRODUCTION: Long-term outcomes of anatomic total shoulder arthroplasty (aTSA) can be compromised by glenoid loosening and failure. The purpose of this study was to evaluate the short- and midterm outcomes of humeral head replacement with glenoid reaming arthroplasty (Ream and Run) for the treatment of advanced glenohumeral osteoarthritis, and to identify associations between preoperative factors and outcomes. METHODS: Forty-nine shoulders (mean age 60 ± 7 years) with minimum 2-year follow-up (mean 4.6 ± 1.7) were evaluated. Forty-three (87.8%) were male. Thirteen (26.5%) had previous nonarthroplasty shoulder surgery. There were 19 (38.8%) Walch type A and 30 (61.2%) type B glenoids. Pre- and postoperative shoulder motion, patient-reported outcomes (PROMs), and health-related quality of life (HRQoL) were assessed. Pre- and postoperative plain radiographs were evaluated. Mixed effects models were used to investigate factors associated with outcomes. RESULTS: Active forward elevation and active external rotation improved from 111.7° ± 23.8° to 139.2° ± 21.1° and 13.3° ± 20.7° to 38.7° ± 14.7°, respectively (P < .001). The mean American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), Disabilities of the Arm, Shoulder, and Hand questionnaire (DASH), Simple Shoulder Test (SST), and visual analog scale (VAS) shoulder pain scores at the most recent follow-up were 86.6 ± 19.9, 10.1 ± 14.1, 10.5 ± 2.2, and 1.5 ± 2.3, respectively. The mean changes of PROMs were significant and exceeded the minimal clinically important difference for aTSA. The percentage maximal possible improvement for ASES, DASH, and SST were greater than 75%. Male sex (P < .008) and not having prior shoulder surgery (P < .04) were significantly associated with better absolute and greater change in PROMs. Age, preoperative shoulder motion, and Walch glenoid classification were not associated with PROMs. Five (10.2%, 95% confidence interval [CI] 1.8%-18.6%) patients underwent revision for pain. Three additional patients were dissatisfied at final follow-up without undergoing revision, resulting in 16.7% (95% CI 6.1%-27.2%) of patients being dissatisfied with their outcome after their initial RnR. Mean Short Form-6 Dimensions scores improved from 0.66 ± 0.12 to 0.77 ± 0.13 and mean EuroQol-5 Dimensions scores improved from 0.68 ± 0.20 to 0.85 ± 0.17 (P < .001). Improvement in HRQoL was significantly associated with nondominant arm treatment, increased age, and greater preoperative SST score. Annual medialization of the humeral head center of rotation was 0.56 ± 1.6 mm/yr. No radiographic measure was associated with long-term PROMs. CONCLUSION: Ream and Run can provide significant and clinically important improvement in PROMs and HRQoL for a high percentage of patients at short- and midterm follow-up. This procedure is an appropriate alternative to aTSA in select patients.

A cattle graph genome incorporating global breed diversity.

Despite only 8% of cattle being found in Europe, European breeds dominate current genetic resources. This adversely impacts cattle research in other important global cattle breeds, especially those from Africa for which genomic resources are particularly limited, despite their disproportionate importance to the continent's economies. To mitigate this issue, we have generated assemblies of African breeds, which have been integrated with genomic data for 294 diverse cattle into a graph genome that incorporates global cattle diversity. We illustrate how this more representative reference assembly contains an extra 116.1 Mb (4.2%) of sequence absent from the current Hereford sequence and consequently inaccessible to current studies. We further demonstrate how using this graph genome increases read mapping rates, reduces allelic biases and improves the agreement of structural variant calling with independent optical mapping data. Consequently, we present an improved, more representative, reference assembly that will improve global cattle research.

Biomechanical Comparison of Dual and Posterior Locking Plates in an Ex Vivo Comminuted Olecranon Fracture Model.

PURPOSE: Comminuted olecranon fractures are commonly fixed with posterior locking plates (PLPs). Though biomechanically validated, this method comes with risks of symptomatic implant prominence and wound breakdown. Dual locking plates (DLPs) placed on the medial and lateral surfaces of the olecranon theoretically avoid these risks and allow for fixation of proximal fracture fragments in multiple planes. A biomechanical comparison of DLP and PLP fixation would help to validate the use of DLPs in comminuted olecranon fractures. METHODS: Seven matched pairs of cadaveric upper extremities were evaluated with quantitative computed tomography scans to evaluate bone mineral density (BMD). Osteotomies simulating comminuted olecranon fractures (Mayo Type IIB) were created and the specimens were fixed either with variable angle PLPs or variable angle DLPs. The specimens were then cyclically loaded and loaded to failure. The ultimate strength, fracture displacement, and mechanism of failure were recorded and compared across groups. The correlation between BMD and ultimate strength was analyzed. RESULTS: The mean total BMD was 0.79 g/cm2 (SD, 0.14 g/cm2). No specimen failed during cyclic testing. Five of 7 PLP specimens and 5 of 7 DLP specimens failed by fracture through the proximal screws though in different planes (sagittal vs axial splits, respectively). The mean ultimate strengths of the PLP (1077 N [SD, 462 N]) and DLP (1241 N [SD, 506 N]) groups were similar. There was a linear relationship between ultimate strength and BMD (R2 = 0.33). CONCLUSION: Dual locking plates display biomechanical properties that suggest that they can be used in the fixation of comminuted olecranon fractures. Catastrophic failure of the fixation constructs occurs around stress risers at the proximal screws rather than due to displacement at the fracture itself. CLINICAL RELEVANCE: Dual locking plate constructs can be considered for use in the fixation of comminuted olecranon fractures.

Temporal and Geographic Trends in Medicare Reimbursement of Primary and Revision Shoulder Arthroplasty: 2000 to 2020.

INTRODUCTION: A comprehensive understanding of the trends for financial reimbursement of shoulder arthroplasty is important as progress is made toward achieving sustainable payment models in orthopaedics. This study analyzes Medicare reimbursement trends for shoulder arthroplasty. We hypothesize that Medicare reimbursement has decreased for shoulder arthroplasty procedures from 2000 to 2020 and that revision procedures have experienced greater decreases in reimbursement. METHODS: The Physician Fee Schedule Look-Up Tool from the Centers for Medicare & Medicaid Services was queried for each Current Procedural Terminology code used in shoulder arthroplasty, and physician reimbursement data were extracted. All monetary data were adjusted for inflation to 2020 US dollars. Both the average annual and the total percentage change in surgeon reimbursement were calculated based on these adjusted trends for all included procedures. Mean percentage change in adjusted reimbursement among primary procedures in comparison to revision procedures was calculated. The mean reimbursement was assessed and visually represented by geographic state. RESULTS: The average reimbursement for all shoulder arthroplasty procedures decreased by 35.5% from 2000 to 2020. Revision total shoulder arthroplasty (TSA) experienced the greatest mean decrease (-44.6%), whereas primary TSA (-23.9%) experienced the smallest mean decrease. The adjusted reimbursement rate for all included procedures decreased by an average of 1.8% each year. The mean reimbursement for revision procedures decreased more than the mean reimbursement for primary procedures (-41.1% for revision, -29.9% for primary; P < 0.001). The mean reimbursement for TSA in 2020, and the percent change in reimbursement from 2000 to 2020, varied by state. DISCUSSION: Medicare reimbursement for shoulder arthroplasty procedures has decreased from 2000 to 2020, with revision procedures experiencing the greatest decrease. Increased awareness and consideration of these trends will be important as healthcare reform evolves, and reimbursements for large joint arthroplasty are routinely adjusted.