Gerard P. Slobogean

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» The propensity score is a patient's modeled probability of receiving a treatment given measured baseline characteristics (covariates). Matching patients with similar scores balances those covariates between groups, approximating the comparability achieved by randomization. » Target trial emulation specifies the protocol of the ideal randomized trial and then reproduces it in observational data, enforcing an explicit eligibility window, time zero (the single point at which eligibility, treatment assignment, and the start of follow-up coincide), and analysis plan. » Regression adjusts for confounders within the outcome model, whereas propensity score matching balances those confounders before outcomes are examined. Propensity matching is preferred for rare outcomes or many confounders, where regression tends to overfit. » Neither propensity matching nor target trial emulation addresses unmeasured confounding, and both lose validity in small single-center cohorts with limited overlap (few treated and untreated patients who resemble one another closely enough to be fairly compared); a randomized trial remains the reference standard when feasible. » When appraising studies using propensity matching or target trial emulation, look for 3 key features: (1) Postmatching covariate balance: Are the treatment groups well balanced after matching? (standardized mean difference <0.10). (2) Positivity: Is there enough overlap in patient characteristics that treated and untreated patients can be fairly compared? (3) Unambiguous “time zero”: Did follow-up begin at the same well-defined starting point for all patients?

Hip fractures in older adults carry substantial perioperative risk, with cardiovascular complications being a major concern. The dual physiologic stress from fracture and surgical repair activates neuroendocrine pathways and creates sympathovagal imbalance. While peripheral nerve blocks are established for analgesia in hip fracture management, their potential to attenuate the surgical stress response and reduce cardiovascular complications remains unclear. This study evaluated the association between peripheral nerve blocks and cardiac events in older adults undergoing hip fracture surgery. This cohort study used the Premier Healthcare Database, including patients aged 65 years or older with hip fractures surgically treated in 2022 or 2023. Peripheral nerve block administration was identified through procedure codes and pharmacy records. Propensity score matching (1:1) balanced baseline characteristics between groups. The primary outcome was myocardial infarction during index hospitalization. Secondary outcomes included other cardiac events and noncardiac complications. All-cause 90-day readmission was an exploratory outcome. Among 23,812 eligible patients, 3,299 (14%) received peripheral nerve blocks. After propensity matching, each group contained 3,299 patients (median age 81 years). Myocardial infarction showed a protective point estimate but did not reach statistical significance (risk ratio [RR] 0.64; 95% confidence interval [CI]:0.37-1.12; p = 0.12). Nerve blocks were associated with reduced acute congestive heart failure (RR 0.47; 95% CI: 0.31-0.72; p < 0.001) and cardiac arrest (RR 0.41; 95% CI: 0.19-0.90; p = 0.03). Nerve blocks were also associated with a reduced risk of 90-day hospital readmission (RR 0.82; 95% CI: 0.72-0.93; p = 0.003). Peripheral nerve blocks were associated with reduced cardiovascular complications in older adults undergoing hip fracture surgery. While myocardial infarction rates were similar between groups, nerve blocks were associated with reduced in-hospital acute congestive heart failure and cardiac arrest. These findings are hypothesis-generating for cardioprotective effects from peripheral nerve blocks. Level III, Therapeutic. See Instructions for Authors for a complete description of levels of evidence.

Background: Early prediction of nonhome discharge after lower extremity fracture treatment may improve care coordination and reduce costs. While preinjury functional status is an established predictor, it is commonly assessed subjectively. We hypothesized that preinjury Apple Health mobility metrics, including step count, walking speed, step length, walking asymmetry, and double support time, would be associated with discharge disposition after fracture management. Methods: We conducted a retrospective cohort study of adults with lower extremity fractures. Preinjury Apple Health mobility data within 26 weeks of injury were analyzed. The primary outcome was discharge home vs. nonhome. Multivariable logistic regression assessed associations between mobility metrics and discharge location, adjusting for age (<65 vs. ≥65 years) and isolated vs. nonisolated fractures. Results: The cohort included 249 patients (median age, 39 years; 58% male). Overall, 179 (72%) were discharged home, and 70 (28%) to nonhome facilities. Patients discharged home were younger and more likely to have isolated fractures (p < 0.001 for both). In the adjusted model (area under the receiver operating characteristic curve, 0.80; 95% confidence interval [CI], 0.74-0.86), higher preinjury step count was strongly associated with discharge disposition. Compared with 5,000 steps/day (OR, 4.21; p = 0.001) were associated with increased odds of home discharge. Walking asymmetry <10% (OR, 3.21; p = 0.01) and faster walking speed (OR per 0.1 m/s, 1.31; p = 0.01) were also associated with higher odds of home discharge. Patients 5,000 steps/day had a 94% probability of home discharge (95% CI, 90%-98%) compared with 8% (95% CI, 1%-16%; p < 0.001) among those ≥65 years with nonisolated injuries and <2,500 steps/day. Conclusions: Preinjury smartphone mobility data were independently associated with discharge disposition after lower extremity fracture treatment. These objective measures may improve perioperative risk stratification and discharge planning in orthopaedic trauma populations. Level of Evidence: Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Background: The contemporary causes of postoperative mortality in orthopedic surgery are not well characterized. Objective: This study aimed to describe the epidemiology of postoperative complications among adult patients who underwent orthopedic surgery and inform their relationships with 30-day mortality. Methods: Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) was a prospective cohort study involving 40,004 adult patients who underwent noncardiac surgery across 28 centers in 14 countries. For the subset of patients who underwent orthopedic surgery, a Cox proportional hazards model was used to determine time-dependent associations between various surgical complications and 30-day postoperative mortality. Analyses were adjusted for preoperative and surgical variables. Results: Among 8385 patients who underwent an orthopedic surgery in VISION, 1.6% (n=132) died within 30 days of surgery. Of the 132 deaths, 63.6% (n=84) occurred in hospital during the index hospitalization, while 36.4% (n=48) occurred after discharge. The incidence of death across the subcategories of orthopedic surgery was above-knee amputation (30/221, 13.6%), internal fixation of femur (29/750, 3.9%), lower leg amputation (9/252, 3.6%), major hip or pelvic surgery (49/2898, 1.7%), major spine surgery (8/1405, 0.6%), and knee arthroplasty (7/2876, 0.2%). A total of 6 postoperative complications (myocardial injury after noncardiac surgery [MINS], major bleeding, infection without sepsis, sepsis, stroke, and atrial fibrillation) were associated with death in adjusted analyses. The greatest attributable fractions of postoperative mortality (ie, proportion of deaths in the cohort that can be attributed to each complication, if causality were established) were from MINS (1454/8385, 17.3%; hazard ratio [HR] 2.08, 95% CI 1.38‐3.14; P <.001; attributable fraction=20.6%), major bleeding (2422/8385, 28.9%; HR 1.95, 95% CI 1.34‐2.85; P <.001; attributable fraction=16.5%), and sepsis (318/8385, 3.8%; HR 6.24, 95% CI 3.85‐10.12; P <.001; attributable fraction=9.7%). Conclusions: The complications most attributable to 30-day mortality following orthopedic surgery were MINS, major bleeding, and sepsis. These findings highlight areas for further study to mitigate perioperative mortality in orthopedic surgery. MINS demonstrated the highest attributable fraction for mortality (20.6%), emphasizing the importance of appropriate MINS screening, diagnosis, and management.

Musculoskeletal disorders are common and can profoundly affect the survival, mobility, and independence of patients. The overall objective of the Musculoskeletal Adaptive Platform Trial (MAPT) is to incrementally compare the effectiveness of available interventions to improve outcomes for adult patients with health conditions affecting physical mobility. The MAPT framework is flexible, allowing the detection of varying levels of meaningful benefit or harm (or equivalence) on the basis of the burden of disease and the available treatments. Treatment comparisons will be evaluated as intervention domains on the platform in order to achieve the overarching objective. Specific objectives for each intervention domain will be included in intervention domain-specific protocol appendices. The primary outcome is a hierarchically assessed composite of death within 120 days, ambulation status at 120 days, and days alive and out of the hospital within 120 days of randomization. Secondary outcomes will include the components of the composite outcome and patient-reported outcomes. Participants will be contacted at 6 weeks, 4 months, 8 months, and 12 months after randomization to ascertain trial outcomes. The MAPT will enable researchers to efficiently evaluate multiple treatment options for patients with musculoskeletal impairments, which may improve patient care and outcomes globally. Clinical Relevance: The MAPT is clinically relevant because it provides a practical framework for rapidly identifying which treatments improve survival, mobility, and recovery in patients with musculoskeletal conditions. It can directly guide better treatment decisions regarding a leading cause of disability.

Background: Clinical trial participants have a right to know the results of the trials in which they participate. Trial results are often not shared directly with participants and concerns with privacy and resource constraints may prevent researchers from contacting participants after trial completion. Questions/Purposes: The objectives of this cross-sectional study were to explore the feasibility of contacting orthopaedic fracture trial participants after trial completion and to determine the preferences and priorities of the participants who wished to know the results. Patients/Methods: Following the publication of the primary manuscript, we attempted to contact participants from the completed PREPARE trial at Hamilton Health Sciences to determine if they would like to know the trial results. We asked participants about their preferences for receiving trial results, their experiences upon learning them, and if they wished to learn which treatment they received. Results: Twenty-eight percent (181/641) of PREPARE trial participants contacted agreed to participate in this study. We found that 95.5% (95% CI 91.0%—97.9%) of respondents wished to know the trial results and the preferred method was through viewing summary posters via an online link (78.2%; 95% CI 71.1%—84.0%). Most felt satisfied after learning the trial results (67.8%; 95% CI 59.5%- 75.2%) and 82.2% (95% CI 75.2%—87.5%) wanted to know which treatment they received. Fifty-one percent (95% CI 42.7%—58.7%) reported that learning the results increased their likelihood of participating in a future trial. Conclusions: Although it was challenging to both contact and re-engage participants after completing an orthopaedic trial that involved minimal participant burden, our study findings suggest that learning the trial results may have a positive impact on individual participants and the research community. Given the limited understanding of results among our respondents, researchers should have processes in place to engage participants meaningfully throughout the trial and proactively discuss with them how the results will be shared once the trial is complete. Level of evidence: IV.

OBJECTIVES: To compare the effectiveness and safety of aspirin versus low-molecular-weight heparin (LMWH) for thromboprophylaxis in 11 high-risk or fracture location subpopulations. METHODS: Design: A post hoc secondary analysis of the published PREVENT CLOT trial. Setting: 21 trauma centers. Patient Selection Criteria: Adult patients with an operatively treated extremity fracture or any pelvic or acetabular fracture were enrolled from April 2017 through August 2021. Patients with only hand or foot fractures, presenting >48 hours after injury, or with a history of venous thromboembolism within 6 months of injury were excluded. The 11 subpopulations included (1) head injury, (2) abdominal injury, (3) spinal injury, (4) thoracic injury, (5) multiply injured patients, (6) obesity, (7) previous venous thromboembolism ≥6 months, (8) isolated upper extremity fracture, (9) isolated lower extremity fracture, (10) isolated pelvic or acetabular fracture, and (11) geriatric femur fracture. Outcome Measures and Comparisons: The primary outcome was 90-day all-cause mortality. Secondary outcomes included nonfatal pulmonary embolism, proximal deep vein thrombosis (DVT), distal DVT, and bleeding events. Outcomes were assessed using Kaplan–Meier estimators and Cox proportional hazards models comparing 81 mg of aspirin versus 30 mg of LMWH twice daily. The threshold for statistical significance was a Bonferroni-corrected alpha of 0.001 to account for multiple comparisons. RESULTS: The largest subpopulations were isolated lower extremity fractures (n = 6289), obesity (n = 4234), and polytrauma with Injury Severity Score (ISS) >16 (n = 1596). No comparison of aspirin versus LMWH within the 11 subpopulations for the 5 outcomes reached the corrected threshold for statistical significance of P < 0.001. However, 5 comparisons of aspirin versus LMWH were less than the conventional P -value of 0.05. Specifically, the aspirin group demonstrated lower mortality in patients with a head injury (difference, −3.2%; 95% CI −6.1% to −0.3%; P = 0.03) or a spine injury (difference, −6.0%; 95% CI −11.7% to −0.3%; P = 0.04) than the LMWH group. The LMWH group demonstrated a lower rate of distal DVTs for patients with a head injury (difference, 4.4%; 95% CI, 0.8% to 8.1%; P = 0.02), thoracic injury (difference, 1.5%; 95% CI, 0.0% to 2.9%; P = 0.04) or with ISS >16 (difference, 1.7%; 95% CI, 0.2% to 3.3; P = 0.03) than the aspirin group. CONCLUSIONS: Within 11 high-risk or fracture location-specific subpopulations, there were no statistically significant differences between aspirin and LMWH in the 90-day rates of all-cause mortality, nonfatal PE, proximal DVT, distal DVT, or bleeding complications at a threshold corrected for multiple comparisons ( P < 0.001). LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.