A Biomechanical Evaluation of Casting Technique and Cast Core Size Effect.

BACKGROUNDS: The goals of this study were to (1) compare the effect of casting technique on biomechanical function with different casting materials and different cast core diameters, and (2) compare the strength of a cast based on the number of layers in relation to the core diameter. METHODS: Two standardized cylindrical cast model sizes were used to simulate forearm and short leg casts (core diameter: 60 mm, 100 mm) with 2 different casting techniques (non-smoothing vs. smoothing with lamination), utilizing 2 casting materials [fiberglass and Plaster of Paris (POP)]. Each cast was created using 3 different layers (Fiberglass: 2 to 4 layers; POP: 3 to 5 layers). Ultimate load-to-failure and flexural rigidity were analyzed through cyclic 4-point bend testing. RESULTS: The biomechanical comparison between forearm and short leg casts were significantly different regardless of the same number of layers for both casting materials and between 2 casting techniques. Increased cast thickness significantly increased the ultimate load-to-failure and bending strength. An increased core diameter size significantly decreased the cast's ultimate load-to-failure (fiberglass: 50% to 108%; POP: 10% to 93%) and bending strength (fiberglass: 17% to 35%; POP: 37% to 49%). Casting technique with smoothing with lamination technique had a negative biomechanical effect on POP and a minimal effect on fiberglass. CONCLUSION: The number of layers to apply for a cast should be based on the size of the extremity. Smoothing and lamination technique did not significantly improve the cast mechanical behavior. CLINICAL RELEVANCE: The findings of this study provide valuable evidence, analysis, and supplementary knowledge that helps guide physicians in proper casting technique.

Athletic Shoulder Test Differences Exist Bilaterally in Healthy Pitchers.

Background: There is a lack of valid and reliable tests that assess upper extremity strength and function for rehabilitation and injury prevention purposes in throwing athletes. The Athletic Shoulder (ASH) test has been proposed as a reliable measure of shoulder strength, but has not yet been studied in baseball pitchers. Hypothesis/Purpose: The purpose of this study was to establish values for healthy baseball pitchers performing the ASH test, compare those values with other common tests of shoulder strength and function, and compare ASH test performance bilaterally. It was hypothesized that the dominant arm would perform significantly better on the ASH test compared to the non-dominant arm. A secondary purpose of the study was to evaluate if ASH test performance was related to fastball velocity in baseball pitchers. It was hypothesized that ASH test performance would positively correlate with fastball velocity. Study Design: Cross-Sectional Study. Methods: College and high school baseball pitchers were recruited to complete shoulder range of motion (ROM), isokinetic shoulder strength, and isometric shoulder strength testing using the ASH test. The ASH test was used to assess force production as a proxy for strength bilaterally at four levels of shoulder abduction (0°, 90°, 135°, and 180°), using a force plate. Approximately one-week later subjects returned for a bullpen session where fastball velocity was recorded with a radar gun. Bilateral differences in passive ROM, isokinetic, and isometric shoulder strength were examined using paired t-tests while linear relationships between isometric shoulder strength and fastball velocity were assessed using Pearson correlations. Results: Thirty-five healthy pitchers participated in the study (19.7 ± 1.8 years). Pitchers demonstrated significantly greater isometric shoulder strength at the 90° and 135° abduction positions with the throwing arm compared to the non-throwing arm. Pitchers also demonstrated commonly observed musculoskeletal adaptations in the throwing arm such as increased passive external rotation, decreased passive internal rotation, and greater internal and external rotator strength during isokinetic testing. Peak force production during the ASH test was not related to fastball velocity. Conclusion: The ASH test is capable of detecting bilateral shoulder strength adaptations commonly observed in other clinical tests in healthy pitchers. Pitchers demonstrated greater isometric peak force during the ASH test at levels of shoulder abduction similar to those observed in pitching. While these results may be intriguing for clinical use, peak force from the ASH test was not correlated to fastball velocity in pitchers, and therefore should be used with caution for predictions in this realm. Level of Evidence: 2. Clinical Relevance: A need exists for objective measures of shoulder strength for rehabilitation and injury risk monitoring in throwing athletes that are easy to administer, have high reliability and validity, and provide minimal re-injury risk to athletes recovering from injury. What is known about the subject: Data from the ASH test has been published previously in non-throwing athletes and was shown to be valid and reliable in that group. However, the test has not been explored widely in throwing athletes who are known to have significant musculoskeletal adaptations to the throwing shoulder. What this study adds to existing knowledge: The results from this study confirm that the ASH test is sensitive enough to detect the adaptations that are present in the healthy throwing athlete's shoulder. Due to the prior proven validity and reliability and these results, the test can be used to monitor throwing arm strength and function during rehabilitation or as a pre/intra-season screening tool to help describe arm health.

Thumb and Index Finger Amputation after Radial Artery Occlusion in a Patient with COVID-19.

The pathophysiology and predictability of radial artery thromboembolic events in patients with COVID-19 is not fully understood. We report a case of thumb and index finger gangrene and multiple digit amputations secondary to digital artery occlusion after radial artery cannulation in a patient admitted with COVID-19 pneumonia and encephalopathy. The exact association, causality, and potential hand manifestations in this patient population is unclear at this time, but is of particular interest in the current state of the pandemic.

Does Surgeon Subspecialty Training Affect Outcomes in the Treatment of Displaced Supracondylar Humerus Fractures in Children?

INTRODUCTION: The effect of the treating surgeon's subspecialty training on the outcomes of managing displaced supracondylar humerus fractures in the pediatric cohort remains under debate. The objective of this study was to examine patient outcomes and treatment variables for these injuries based on the surgeon subspecialty training. METHODS: A retrospective study of children who had undergone primary closed reduction and percutaneous fixation for displaced supracondylar humerus fractures was done from January 2012 through May 2019. The following four groups with differing orthopaedic subspecialty training were evaluated: (1) pediatric fellowship trained (2) trauma fellowship trained, (3) sports medicine fellowship trained, and (4) all others. Outcomes examined included time to surgery, surgical time, fluoroscopy usage, postoperative follow-up protocols, radiographic measurements of alignment, and complications between surgeon groups. RESULTS: Two hundred thirty-one cases were included (mean age 6 ± 2 years). Pediatric fellowship-trained surgeons took patients to surgery in a more delayed fashion (>12 hours, P = 0.02). Surgical time and fluoroscopy usage were significantly shorter for pediatric fellowship-trained surgeons (P < 0.001). No statistical difference was noted in pin configuration constructs between the groups. Pediatric fellowship-trained surgeons, on average, saw patients two times postoperatively within a year with most patients being within 30 days. Complications were not statistically different between the groups. CONCLUSIONS: Pediatric fellowship-trained orthopaedic surgeons provide more efficient care on a more delayed basis for displaced supracondylar humerus fractures than other subspecialty-trained orthopaedic surgeons. However, if barriers exist that limit the practicality or availability of these specialists, nonpediatric fellowship-trained surgeons achieve similar and satisfactory outcomes. LEVEL OF EVIDENCE: Level III retrospective cohort study.

Prior Anterior Cruciate Ligament Reconstruction Effects on Future Total Knee Arthroplasty.

BACKGROUND: The impact of prior anterior cruciate ligament (ACL) reconstruction on total knee arthroplasty (TKA) has rarely been studied. The objective of this study was to compare intraoperative characteristics in patients who underwent TKA with pre-existing hardware from prior ACL reconstruction with a matched cohort control group. METHODS: A retrospective study of patients who had undergone primary TKA with pre-existing hardware from prior ACL reconstruction was performed from June 2012 through June 2017. These patients were 2-to-1 matched to the ACL group based on similar patient demographic and provider variables. Outcomes investigated included operative time, estimated blood loss (EBL), and postoperative complications. RESULTS: One hundred one patients met the inclusion/exclusion criteria. The mean age was 54 ± 9 years, and the mean body mass index was 32.6 ± 6.5 kg/m2. The ACL group was divided into 4 subgroups: group 1, no pre-existing hardware removed (22 TKAs); group 2, pre-existing hardware removed from the femur only (8 TKAs); group 3, pre-existing hardware removed from the tibia only (45 TKAs); and group 4, pre-existing hardware removed from both the femur and tibia (26 TKAs). There was no statistical difference in EBL and postoperative complication between the ACL group and controls. Statistical differences were detected between 2 subgroups regarding mean operative time variables: ACL group 3 (74 ± 23 minutes; control: 64 ± 21 minutes, P = .020) and group 4 (79 ± 24 minutes; control: 65 ± 19 minutes, P = .010). CONCLUSION: Hardware retained, especially on the tibia, from prior ACL reconstruction has a major impact on TKA surgical procedure operative time but not on EBL and/or complications.