BACKGROUND: The purpose of this study is to evaluate the relationship between multiple radiographic measures of lateralization and distalization and clinical outcome scores after reverse total shoulder arthroplasty (RTSA). METHODS: We retrospectively evaluated all RTSAs performed by the senior author between January 1, 2007, and November 1, 2017. We then evaluated the visual analog scale for pain (VAS pain), Simple Shoulder Test (SST), and American Shoulder and Elbow Surgeons (ASES) scores and complication and reoperation rates at a minimum of 2-year follow-up. We measured preoperative and postoperative (2-week) radiographs for the lateralization shoulder angle (LSA), the distalization shoulder angle (DSA), lateral humeral offset (LHO), and distance from glenoid to lateral aspect of the greater tuberosity (GLAGT). A multivariable analysis was performed evaluating the effect of the postoperative radiographic measurements on final patient reported outcomes (ASES scores, SST, VAS pain). RESULTS: The cohort included 216 shoulders from unique patients who had patient reported outcome scores available at a minimum of 2-year follow-up (average, 4.0±1.9 years) for a total follow-up rate of 70%. In the multivariable models, more lateralization (LSA) was associated with worse final ASES scores -0.52 (95% CI: -0.88 to -0.17; p=0.004), and more distalization (DSA) was associated with better final ASES scores 0.40 (95% CI: 0.11, 0.69; p=0.007). More lateralization (LSA) was associated with worse final SST scores -0.06 (95% CI: -0.11, -0.003; p=0.039). Finally, greater distalization (DSA) was associated with lower final VAS pain scores, Ratio = 0.98 (95% CI: 0.96, 1.00; p=0.021). CONCLUSION: Greater distalization and less lateralization are associated with better function and less pain after Grammont-style RTSA. If utilizing a Grammont-style implant, remaining consistent with Grammont's principles of implant placement will afford better final clinical outcomes.
Background: The impact of single-sport specialization on performance and injury risk in youth and adolescent athletes remains debated. The purpose of this study was to determine the incidence of single-sport specialization and its association with pitch velocity, pitcher utilization, range of motion, strength, and injury history. Methods: High school pitchers in the Northeastern, Southeastern, Midwestern, and Western Regions of the United States were prospectively recruited. Prior to the season, pitchers were surveyed about their basic demographics, sport participation history, and injury history. At this timepoint, a standardized physical examination was performed and max pitch velocity was measured. They were then prospectively followed over the ensuing high school season, where pitch utilization and counts were followed and injuries were tracked. Results: Across the study, 115 pitchers were recruited, of whom 53% played baseball as their only sport and 47% played other sports. Single- position specialization within baseball was uncommon as 90% of athletes played positions other than pitcher. There were no differences in range of motion, strength, or pitch velocity between multisport athletes and single-sport specialists. Within the multisport group, 26% reported a history of injury, while 38% of the single-sport specialists reported a history of injury (P = .179). There were no significant differences in pitcher utilization between multisport athletes and single-sport specialists. Only a single prospective injury occurred in the 115 players. Conclusion: Although single-sport specialization is common, nearly half of all high school pitchers in this study were multisport athletes. While injury history was generally similar between the two groups, single-sport baseball players did not have the following: improved motion, increased strength, higher ball velocity, or greater pitching volumes during the high school baseball season compared to multisport athletes. Accordingly, single-sport specialization did not have a competitive advantage for these high school pitchers based on the performance factors studied. Further prospective studies are necessary to understand the association between single-sport specialization and injury risk in high school baseball players.
