A cost-utility analysis comparing the cost-effectiveness of simultaneous and staged bilateral total knee arthroplasty.

BACKGROUND: The safety and efficacy of simultaneous or staged bilateral total knee arthroplasty have long been debated among orthopaedic surgeons. Advocates for simultaneous bilateral total knee arthroplasty posit that the benefits of decreased costs and recovery time, with no difference in functional outcomes, outweigh the economic costs of potential complications. The purpose of the study was to conduct a cost-utility analysis comparing simultaneous bilateral total knee arthroplasty with staged bilateral total knee arthroplasty. METHODS: A Markov model was designed to compare the cost-effectiveness of simultaneous bilateral total knee arthroplasty with that of staged bilateral total knee arthroplasty. Nationwide Inpatient Sample data sets from 2004 to 2007 were used to identify 24,574 simultaneous and 382,496 unilateral procedures. On the basis of the codes of the International Classification of Diseases, Ninth Revision, Clinical Modification, perioperative complications were categorized as minor, major, and mortality, and respective probability values were calculated. Nationwide Inpatient Sample data were used to determine hospital costs conditional on procedure type and complications. Rehabilitation costs, anesthesia costs, and heath utilities were estimated from the literature. To minimize selection bias, propensity score matching was used to match the groups on comorbid conditions, socioeconomic variables, and hospital characteristics. RESULTS: Using the matched sample, all complication rates were higher for the staged group. The estimated mean cost (in 2012 U.S. dollars) was $43,401 for simultaneous bilateral total knee arthroplasty compared with $72,233 for staged bilateral total knee arthroplasty. The quality-adjusted life years gained were 9.31 for simultaneous bilateral total knee arthroplasty and 9.29 for staged bilateral total knee arthroplasty. On the basis of these matched results, simultaneous bilateral total knee arthroplasty dominated staged bilateral total knee arthroplasty with lower costs and better outcomes. CONCLUSIONS: On the basis of this analysis, simultaneous bilateral total knee arthroplasty is more cost-effective than staged bilateral total knee arthroplasty, with lower costs and better outcomes for the average patient. These data can inform shared medical decision-making when bilateral total knee arthroplasty is indicated.

MRI issues for ballistic objects: information obtained at 1.5-, 3- and 7-Tesla.

BACKGROUND CONTEXT: Few studies exist for magnetic resonance imaging (MRI) issues and ballistics, and there are no studies addressing movement, heating, and artifacts associated with ballistics at 3-tesla (T). Movement because of magnetic field interactions and radiofrequency (RF)-induced heating of retained bullets may injure nearby critical structures. Artifacts may also interfere with the diagnostic use of MRI. PURPOSE: To investigate these potential hazards of MRI on a sample of bullets and shotgun pellets. STUDY DESIGN: Laboratory investigation, ex vivo. METHODS: Thirty-two different bullets and seven different shotgun pellets, commonly encountered in criminal trauma, were assessed relative to 1.5-, 3-, and 7-T magnetic resonance systems. Magnetic field interactions, including translational attraction and torque, were measured. A representative sample of five bullets were then tested for magnetic field interactions, RF-induced heating, and the generation of artifacts at 3-T. RESULTS: At all static magnetic field strengths, non-steel-containing bullets and pellets exhibited no movement, whereas one steel core bullet and two steel pellets exhibited movement in excess of what might be considered safe for patients in MRI at 1.5-, 3- and 7-Tesla. At 3-T, the maximum temperature increase of five bullets tested was 1.7°C versus background heating of 1.5°C. Of five bullets tested for artifacts, those without a steel core exhibited small signal voids, whereas a single steel core bullet exhibited a very large signal void. CONCLUSIONS: Ballistics made of lead with copper or alloy jackets appear to be safe with respect to MRI-related movement at 1.5-, 3-, and 7-T static magnetic fields, whereas ballistics containing steel may pose a danger if near critical body structures because of strong magnetic field interactions. Temperature increases of selected ballistics during 3-T MRI was not clinically significant, even for the ferromagnetic projectiles. Finally, ballistics containing steel generated larger artifacts when compared with ballistics made of lead with copper and alloy jackets and may impair the diagnostic use of MRI.

Comparison of pediatric outcomes data collection instrument scores and range of motion before and after shoulder tendon transfers for children with brachial plexus birth palsy.

BACKGROUND: Children with brachial plexus birth palsy (BPBP) may undergo shoulder external rotation tendon transfers (ERTT) to improve function. In terms of outcome measurements, and according to the World Health Organization International Classification of Functioning, Disability, and Health model, ERTT reduces impairment as measured by range of motion (ROM), but has not been shown to improve activity and participation. Furthermore, correlation between these outcome measures has not been established. The Pediatric Outcomes Data Collection Instrument (PODCI) is a well-validated musculoskeletal health questionnaire that addresses activity and participation components of function. The aim of this study is to determine whether PODCI scores improve after ERTT, and whether this improvement correlates with improvement in ROM. METHODS: A total of 23 children with a mean age of 6.3 years (range, 4.4-12.8 years) with BPBP and standard indications for ERTT underwent preoperative and 1-year postoperative shoulder ROM measurements, and parental completion of the PODCI. Change in ROM was compared with change in PODCI scores to determine if these were correlated. RESULTS: Average range of active shoulder abduction improved 35 degrees (P < 0.001), and average range of active external rotation improved 41 degrees (P < 0.001). The PODCI scores for Upper Extremity Function, Sports Function, and Global Function improved (12 points [P < 0.001], 4 points [P = 0.04], and 6 points [P = 0.001], respectively). Improvement in ROM did not correlate with improvement in PODCI scores. However, postoperative peak active abduction correlated strongly with postoperative PODCI scores for Upper Extremity Function, and Global Function (rs = 0.712 [P < 0.001], rs = 0.735 [P < 0.001], respectively), and moderately with Transfers and Basic Mobility and Sports Function scores (rs = 0.496 [P=0.016], rs = 0.449 [P = 0.032], respectively). CONCLUSIONS: For children with BPBP, ERTT is associated with reduced impairment and improved activity and participation. Maximum postoperative abduction is positively associated with PODCI scores, but change in ROM is not. Further study is needed to determine if ceiling effects or other factors account for the lack of correlation between these outcome measures. LEVEL OF EVIDENCE: Level of evidence IV, case series.