Charles Nofsinger

Objective Preoperative Measurement of Anterior Glenoid Bone Loss: A Pilot Study of a Computer-Based Method Using Unilateral 3-Dimensional Computed Tomography

PURPOSE The purpose of this study was to evaluate the reproducibility of unilateral computed tomography (CT) measurement of glenoid surface area, based on the typically circular geometry of the inferior glenoid. METHODS This study used 3-dimensional shoulder CT scans before reconstruction for anterior instability. The en face CT views of the normal and abnormal glenoids were randomized and evaluated by 3 independent observers (2 experienced shoulder surgeons and 1 medical student). ImageJ (National Institutes of Health, Bethesda, MD) was used to overlay a perfect circle that was fit to the glenoid. The anterior aspect of the circle was then adjusted to match the true anatomic contour of the anterior glenoid. This adjusted region was used to determine the percentage of the perfect circle occupied by the glenoid, which we defined as the anatomic glenoid index (AGI). RESULTS For the 23 normal shoulders, the AGI reflected a nearly perfect fit of the circle, with very high consistency and reliability among the 3 observers. Overall, mean AGI for the normal shoulders was 100.5%, with an SD of 2.2%. For the 12 shoulders that underwent Bankart repair, the overall AGI was 92.1% ± 5.2%, and 9 of 12 patients had an AGI below the threshold of 96.1%. For the 11 shoulders that underwent Latarjet reconstruction, the overall AGI was 89.6% ± 4.7%. CONCLUSIONS This study confirms that the normal inferior glenoid surface is a nearly perfect circle with remarkably low variability. This observation allows for determination of a tight reference range that can be applied to clinical analysis of unilateral CT reconstructions of symptomatic shoulders. This pilot study evaluates a simple and reliable method for determination of the AGI, creating an anatomic preoperative description of bone loss. LEVEL OF EVIDENCE Level III, retrospective comparative study.

Diagnostic ultrasound in sports medicine: current concepts and advances.

Diagnostic ultrasound is a valuable imaging tool that is slowly gaining in popularity among sports medicine clinicians. Commonly referred to as “musculoskeletal ultrasound,” its valuable role in assisting with sports medicine diagnoses has been to date underused for a variety of reasons. Effective clinical usage for sports medicine diagnoses includes commonly seen conditions such as rotator cuff disease, ulnar collateral ligament of the elbow injury, and internal derangement of the knee, among many others. Limitation of clinical usage has been deterred by the cost of the unit, perception of time associated with assessment procedures, and the lack of formal training associated with diagnostic implementation. However, when properly used, musculoskeletal ultrasound can increase the accuracy of diagnosis and treatment, improve time to treatment intervention, and improve patient satisfaction. The purpose of this paper is to review the fundamentals of musculoskeletal ultrasound and present its specific diagnostic uses.

FLS Skill Acquisition: A Comparison of Blocked vs Interleaved Practice

INTRODUCTION Fundamentals of Laparoscopic Surgery (FLS) certification is required for general surgery. The recommended practice for learning FLS is to practice tasks one at a time until proficient (blocked practice). Learning theory suggests that interleaved practice, a method in which tasks are rotated rather than learned one at a time, may result in superior learning. METHOD Residents were randomized into 1 of 2 groups: blocked practice or interleaved practice. We compared the performance of residents across groups over 20 trials of each of 4 FLS tasks (peg transfer, pattern cut, extracorporeal suture, and intracorporeal suture). Four weeks later, participants returned to the laboratory and completed 2 additional trials of each of the 4 tasks. RESULTS Performance on each of the tasks improved with increased practice. The interleaved group showed significantly better performance on the peg transfer task; trends favoring the interleaved group resulted for the other tasks. Standardized mean differences in favor of the interleaved group were substantial both at the end of practice and at follow-up (with the exception of the pattern cut). CONCLUSION Interleaved practice appears to have advantages over blocked practice in developing and retaining FLS skills. We encourage others to experiment with the method to confirm our findings.

Surface Electromyography of the Forearm Musculature During the Windmill Softball Pitch

Background: Previous studies investigating the windmill softball pitch have focused primarily on shoulder musculature and function, collecting limited data on elbow and forearm musculature. Little information is available in the literature regarding the forearm. This study documents forearm muscle electromyographic (EMG) activity that has not been previously published. Purpose: Elbow and upper extremity overuse injuries are on the rise in fast-pitch softball pitchers. This study attempts to describe forearm muscle activity in softball pitchers during the windmill softball pitch. Overuse injuries can be prevented if a better understanding of mechanics is defined. Study Design: Descriptive laboratory study. Methods: Surface EMG and high-speed videography was used to study forearm muscle activation patterns during the windmill softball pitch on 10 female collegiate-level pitchers. Maximum voluntary isometric contraction of each muscle was used as a normalizing value. Each subject was tested during a single laboratory session per pitcher. Data included peak muscle activation, average muscle activation, and time to peak activation for 6 pitch types: fastball, changeup, riseball, curveball, screwball, and dropball. Results: During the first 4 phases, muscle activity (seen as signal strength on the EMG recordings) was limited and static in nature. The greatest activation occurred in phases 5 and 6, with increased signal strength, evidence of stretch-shortening cycle, and different muscle characteristics with each pitch style. These 2 phases of the windmill pitch are where the arm is placed in the 6 o’clock position and then at release of the ball. The flexor carpi ulnaris signal strength was significantly greater than the other forearm flexors. Timing of phases 1 through 5 was successively shorter for each pitch. There was a secondary pattern of activation in the flexor carpi ulnaris in phase 4 for all pitches except the fastball and riseball. Conclusion: During the 6 pitches, the greatest muscular activity was in phases 5 and 6. Flexor carpi ulnaris activity was greatest among the muscles tested. The riseball had the highest peak activity, but the curveball and dropball had the highest average signal strength. This muscle activity correlates with increasing distraction in the elbow, suggesting that flexor muscles act to counterdistract the elbow as they do for the baseball pitch. Clinical Relevance: Windmill pitchers are unique among overhead athletes as they throw, on average, more pitches per overhead athlete. Understanding the mechanics and physiology of the elbow in windmill pitchers is crucial to prevention and treatment of these increasingly common elbow injuries. This study establishes baseline data that will be useful to further prevent windmill pitch elbow injury.