Faculty Bibliography

BACKGROUND: Total shoulder arthroplasty (TSA) may be associated with substantial blood loss, and some patients require perioperative blood transfusion. Possible blood transfusion methods include predonated autologous blood transfusion, perioperative autologous blood transfusion, and allogeneic blood transfusion (ALBT). The purposes of the present study were to assess the incidence and recent trends over time of blood transfusion in TSA and analyze patient and hospital characteristics that affect the risk of ALBT. METHODS: This study used national hospital discharge data from the National Inpatient Sample between 2000 and 2009. The data were used to generate the overall blood transfusion rate, and linear regression was used to assess trends in transfusion patterns over time. Logistic regression analysis was performed to analyze which patient and hospital characteristics independently influence the likelihood that a given patient undergoes ALBT. RESULTS: The overall blood transfusion rate (ie, the proportion of patients who received at least 1 transfusion of any kind) was 6.7%. This rate increased over time, from 4.9% in 2000 to 7.1% in 2009 (P < .001). Risk factors associated with ALBT included age, gender, race, insurance status, hospital region, and hospital annual caseload. CONCLUSIONS: The increase in overall blood transfusion rate in TSA found in the present study may be related to factors specific to TSA, such as the introduction of reverse total shoulder arthroplasty during the study period. A variety of patient and hospital characteristics contribute to the risk of undergoing ALBT.

This study analyzes the muscle moment arms of three different reverse shoulder design philosophies using a previously published method. Digital bone models of the shoulder were imported into a 3D modeling software and markers placed for the origin and insertion of relevant muscles. The anatomic model was used as a baseline for moment arm calculations. Subsequently, three different reverse shoulder designs were virtually implanted and moment arms were analyzed in abduction and external rotation. The results indicate that the lateral offset between the joint center and the axis of the humerus specific to one reverse shoulder design increased the external rotation moment arms of the posterior deltoid relative to the other reverse shoulder designs. The other muscles analyzed demonstrated differences in the moment arms, but none of the differences reached statistical significance. This study demonstrated how the combination of variables making up different reverse shoulder designs can affect the moment arms of the muscles in different and statistically significant ways. The role of humeral offset in reverse shoulder design has not been previously reported and could have an impact on external rotation and stability achieved post-operatively. (c) 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:605-613, 2015.

OBJECTIVES:: To empirically define a "delay" for hip fracture surgery based on clinical outcomes, and to identify patient demographics and hospital factors contributing to surgical delay. DESIGN:: Retrospective database analysis. SETTING:: Hospital discharge data. PATIENTS/PARTICIPANTS:: A total of 2,121,215 patients undergoing surgical repair of hip fracture in the National Inpatient Sample (NIS) between 2000 and 2009. INTERVENTION:: Internal fixation or partial/total hip replacement. MAIN OUTCOME MEASUREMENTS:: Logistic regressions were performed to assess the effect of surgical timing on in-hospital complication and mortality rates, controlling for patient characteristics and hospital attributes. Subsequent regressions were performed to analyze which patient characteristics (age, gender, race, comorbidity burden, insurance status, and day of admission) and hospital factors (size, teaching status, and region) independently contributed to the likelihood of surgical delay. RESULTS:: Compared to same-day surgery, each additional day of delay was associated with a significantly higher overall complication rate. However, next-day surgery was not associated with an increased risk of in-hospital mortality. Surgery 2 calendar days (OR: 1.13) and 3+ days (OR: 1.33) following admission was associated with higher mortality rates. Based on these findings, "delay" was defined as surgery performed two or more days after admission. Significant factors related to surgical delay included comorbidity score, race, insurance status, hospital region, and day of admission. CONCLUSIONS:: Surgical delay in hip fracture care contributes to patient morbidity and mortality. A variety of patient and hospital characteristics seem to contribute to surgical delay, and point to important health care disparities. LEVEL OF EVIDENCE:: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

BACKGROUND: The purpose of this study was to evaluate the effect of sling immobilization on driving performance with use of a driving simulator. METHODS: This is a prospective trial with a cohort of 21 healthy volunteers comparing their driving ability with and without sling immobilization on their dominant (driving) extremity. Multiple variables, including number of collisions, off-road excursions, and centerline crossings, were measured with a validated driving simulator. Trials were separated by 2 weeks to control for "adaptations" to the simulator. Statistical significance was found in collisions between sling and no-sling tests. RESULTS: The total number of collisions for trial 1 (no sling) was 36 (mean, 1.7 +/- 1.2) compared with 73 (3.7 +/- 1.6) (P < .01) for trial 2 (sling immobilization). Approximately 70% of participants with upper extremity immobilization were involved in >/=3 collisions; approximately 70% of no-sling participants were involved in