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.

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.