Hip and glenohumeral rotational range of motion in healthy professional baseball pitchers and position players.

BACKGROUND: Research suggests that limitations in the hip motion of baseball players may lead to altered motion at the glenohumeral joint to maintain throwing velocity, thereby predisposing the upper extremity to injury. PURPOSE: To measure and evaluate the correlation between hip and shoulder rotational range of motion (ROM) in healthy professional baseball players. STUDY DESIGN: Descriptive laboratory study. METHODS: Ninety-nine professional baseball players (50 pitchers and 49 position players; mean age ± standard deviation [SD], 22 ± 2.8 years; mean height ± SD, 187 ± 5.4 cm; mean weight ± SD, 81.6 ± 7.7 kg) with no history of hip or shoulder injury were tested. Dominant and nondominant hip and glenohumeral joints were measured for the following passive ROM variables: (1) hip internal rotation (IR), (2) hip external rotation (ER), (3) total hip rotational ROM (IR + ER), (4) isolated glenohumeral IR, (5) isolated glenohumeral ER, and (6) total glenohumeral rotational ROM (IR + ER). RESULTS: Statistically, hip ER and total hip rotational ROM were greater in position players than in pitchers and less in the lead leg compared with the stance leg hip with groups combined; however, differences are not clinically meaningful. Pitchers had more glenohumeral rotational ROM than did position players. For all players, glenohumeral motion had less IR and greater ER in the throwing arm than the nonthrowing arm, but total glenohumeral rotational ROM was equivalent between sides. The correlations between hip and glenohumeral ROM were little, if any, and ranged from r = -0.19 to 0.11 (P = .006-.94) for all players and r = -0.29 to 0.23 (P = .04-.97) for pitchers only. CONCLUSION: These data suggest no clinically meaningful differences in hip ROM between pitchers and position players and between lead leg and stance legs of all players. There is little or no relationship between hip and glenohumeral ROM in healthy professional baseball players. CLINICAL RELEVANCE: The study findings add to the growing body of evidence that suggests an absence of chronic hip ROM adaptations. It is therefore suggested that in the hip, unlike the glenohumeral joint, symmetry in ROM between player positions and dominant and nondominant sides should be expected in healthy professional baseball pitchers and position players.

Biomechanical evaluation of pedicle screws versus pedicle and laminar hooks in the thoracic spine.

BACKGROUND CONTEXT: Pedicle screws have been shown to be superior to hooks in the lumbar spine, but few studies have addressed their use in the thoracic spine. PURPOSE: The objective of this study was to biomechanically evaluate the pullout strength of pedicle screws in the thoracic spine and compare them to laminar hooks. STUDY DESING/SETTING: Twelve vertebrae (T1-T12) were harvested from each of five embalmed human cadavers (n=60). The age of the donors averaged 83+8.5 years. After bone mineral density had been measured in the vertebrae (mean=0.47 g/cm(3)), spines were disarticulated. Some pedicles were damaged during disarticulation or preparation for testing, so that 100 out of a possible 120 pullout tests were performed. METHODS: Each vertebra was secured using a custom-made jig, and a posteriorly directed force was applied to either the screw or the claw. Constructs were ramped to failure at 3 mm/min using a Mini Bionix II materials testing machine (MTS, Eden Prairie, MN). RESULTS: Pedicle claws had an average pullout strength of 577 N, whereas the pullout strength of pedicle screws averaged 309 N. Hooks installed using the claw method in the thoracic spine had an overwhelming advantage in pullout strength versus pedicle screws. Even in extremely osteoporotic bone, the claw withstood 88% greater pullout load. CONCLUSION: The results of this study indicate that hooks should be considered when supplemental instrumentation is required in thoracic vertebrae, especially in osteoporotic bone.

Injury risk in professional basketball players: a comparison of Women's National Basketball Association and National Basketball Association athletes.

BACKGROUND: Gender-based differences in injury rates have been reported in scholastic and collegiate basketball. The purpose of this study was to retrospectively compare injury rates in women's and men's professional basketball. HYPOTHESIS: Female professional basketball players are injured at a higher rate than are men. STUDY DESIGN: Cohort study (prevalence); Level of evidence, 2. METHODS: Women's National Basketball Association and National Basketball Association injury data were retrospectively reviewed for 6 full seasons. The frequency of all injuries and the rate of game-related injuries were calculated. RESULTS: Complete player profiles were obtained on 702 National Basketball Association athletes and 443 Women's National Basketball Association athletes who competed in their respective leagues during the data collection period. Total game exposures totaled 70,420 (National Basketball Association) and 22,980 (Women's National Basketball Association). Women's National Basketball Association athletes had a higher overall game-related injury rate (24.9 per 1000 athlete exposures; 95% confidence interval, 22.9-26.9; P < .05) when compared with National Basketball Association athletes (19.3 per 1000 athlete exposures; 95% confidence interval, 18.3-20.4) and sustained a higher rate of lower extremity injuries (14.6 per 1000 athlete exposures; 95% confidence interval, 13.1-16.2; P < .05) than seen in the National Basketball Association (11.6 per 1000 athlete exposures; 95% confidence interval, 10.8-12.4). The lower extremity was the most commonly injured body area (65%), and lateral ankle sprain (13.7%) was the most common diagnosis in both leagues. The incidence of game-related knee injury was higher in Women's National Basketball Association players. The incidence of anterior cruciate ligament injury in the National Basketball Association (n = 22, 0.8%) and Women's National Basketball Association (n = 14, 0.9%) accounted for 0.8% of the 4446 injuries reported. CONCLUSION: The lower extremity is the most frequently injured body area in both leagues, and Women's National Basketball Association athletes are more susceptible than are National Basketball Association athletes. There were, however, few statistical differences in the actual injuries occurring between the 2 leagues.