Clinical Scenario: Ulnar collateral ligament injuries are common in baseball pitchers, with excessive elbow varus torque linked to medial elbow injuries. Trunk tilt, or motion in the frontal plane, could be an identifiable and modifiable factor in medial elbow loading. Clinical Question: In high school through professional baseball pitchers, how does increased contralateral trunk tilt compared with no/limited contralateral trunk tilt influence elbow varus torque? Summary of Key Findings: Four studies were included: all were labeled as “controlled” or “descriptive laboratory studies,” representing cross-sectional observational analytic design. One study compared biomechanics of professional pitchers with and without ulnar collateral ligament reconstruction. Two studies measured biomechanics in college pitchers, one of which also included simulations of joint angles. The fourth study measured biomechanics of high school pitchers. All studies measured trunk tilt and its relationship to elbow varus torque, with 3 of the studies linking increased contralateral trunk tilt with increased elbow varus torque. Clinical Bottom Line: Moderate evidence indicated as contralateral trunk tilt increased, so did elbow varus torque, indicating trunk tilt may be a modifiable factor to decrease medial elbow loading during pitching. Strength of Recommendation: Majority consistent findings from the level 3 cross-sectional observational analytic designs suggest grade B evidence in support of trunk tilt as a factor in increasing elbow varus torque.
Sierra Hakanson, Samuel T. Johnson, Emily C. Norcross, and Cathleen N. Brown
Germanna M. Barbosa, Larissa P. Ribeiro, Ana B. Nasser, Gretchen D. Oliver, and Paula R. Camargo
Context: Understanding the musculoskeletal adaptations in the shoulder complex of varying ages of tennis athletes may suggest preventive protocols and conditioning and rehabilitation programs to this population. This study aimed to generate a bilateral descriptive profile of shoulder flexibility, scapular and clavicular position, and muscle strength in pediatric and adult amateur tennis athletes. The outcome measures were compared between groups and sides. The number and percentage of athletes “at risk” according to cutoff values for shoulder range of motion (ROM) were also analyzed. Design: Cross-sectional study. Methods: 36 pediatric and 28 adult amateur tennis athletes were tested. Outcome measures were ROM of shoulder flexion, abduction, internal and external rotation, posterior capsule tightness, pectoralis minor index (PMI), scapular upward rotation, clavicular elevation, and strength of the external rotators, serratus anterior, and lower trapezius of the dominant/nondominant sides. Results: Pediatric athletes had greater dominant side external rotation (P = .01) and total ROM (P = .04), increased Low Flexion test (P = .01), and decreased PMI (P = .01) compared with the adults. Bilaterally, the pediatric athletes had greater dominant side external rotation ROM (P < .01) and decreased PMI (P = .002) as compared with their nondominant side, whereas the adults displayed lower values on posterior capsule tightness (P = .01) and decreased PMI (P = .02) on their dominant side compared with their nondominant side. For the remaining outcomes, no interaction effects were observed. The cutoff values for shoulder ROM showed that several athletes were “at risk” of shoulder problems. Conclusion: Upper extremity adaptations at the shoulder are present in both pediatric and adult tennis athletes. These data can assist clinicians in better understanding the biomechanical adaptations in the shoulder of amateur tennis athletes in different age groups.
Eric R. Levasseur, Kevin D. Dames, Mark A. Sutherlin, Alyson Dearie, and Sonya Comins
Collegiate- and elite-level swimmers can see extraordinary volumes in training throughout a season. Consequentially, injury and dysfunction in the shoulder are common in competitive swimmers. This study investigated whether preseason Kerlan-Jobe Orthopedic Clinic Questionnaire scores could identify collegiate swimmers who sustained a shoulder injury during an athletic season. A Kerlan-Jobe Orthopedic Clinic Questionnaire score of ≥81 was able to identify swimmers who did not sustain an injury versus those who did. The receiver operating characteristics demonstrated an area under the curve of 0.820, p < .004. A Kerlan-Jobe Orthopedic Clinic Questionnaire score of 81 had a sensitivity of 1.00 and specificity of 0.333. The current findings suggest that selective preseason patient-reported outcome measures could be utilized as a preparticipation screening tool to investigate athlete readiness to compete.
Lilly H. VanDeMark, Christina B. Vander Vegt, Cassie B. Ford, Jason P. Mihalik, and Erik A. Wikstrom
Context: Prophylactic and rehabilitative balance training is needed to maximize postural control and develop appropriate sensory organization strategies. Partially occluding vision during functional exercise may promote appropriate sensory organization strategies, but little is known about the influence of partially occluded vision on postural control in those with and without a history of musculoskeletal injury. Objective: To determine the effect of increasing levels of visual occlusion on postural control in a heterogeneous sample of those with and without chronic ankle instability (CAI). The secondary objective was to explore postural control responses to increasing levels of visual occlusion among those with unilateral and bilateral CAI relative to uninjured controls. Design: Cross-sectional. Setting: Sports medicine research laboratory. Patients or Other Participants: Twenty-five participants with unilateral CAI, 10 with bilateral CAI, and 16 participants with no history of lower extremity injury. Main Outcome Measures: All participants completed four 3-minute postural control assessments in double-limb stance under the following 4 visual conditions: (1) eyes open, (2) low occlusion, (3) high occlusion, and (4) eyes closed. Low- and high-occlusion conditions were produced using stroboscopic eyewear. Postural control outcomes included time-to-boundary minima means in the anteroposterior (TTB-AP) and mediolateral directions (TTB-ML). Repeated-measures analysis of variances tested the effects of visual condition on TTB-AP and TTB-ML. Results: Postural control under the eyes-open condition was significantly better (ie, higher) than the limited visual occlusion and eyes-closed conditions (P < .001) for TTB-AP and TTB-ML. For TTB-AP only, partially occluded vision resulted in better postural control than the eyes-closed condition (P ≤ .003). Conclusions: Partial and complete visual occlusion impaired postural control during dual-limb stance in a heterogeneous sample of those with and without CAI. Stroboscopic eyewear appears to induce postural control impairments to the same extent as complete visual occlusion in the mediolateral direction.
Kyeongtak Song, Kyle B. Kosik, Phillip A. Gribble, and Erik A. Wikstrom
Context: Quantifying early posttraumatic ankle osteoarthritis pathogenesis using compositional magnetic resonance (MR) imaging sequences is becoming more common. These MR sequences are often manually segmented to isolate the cartilage of interest before cartilage compositional values (eg, T1ρ or T2) are quantified. However, limited information is available regarding the reliability and reproducibility of manual segmentation for the entire talar dome. Objective: The purpose of this study was to determine the intraobserver and interobserver reliability of manually segmenting T1ρ MR sequences of the entire talar dome and 4 subregions of interest. Design: Descriptive observational study. Setting: Laboratory. Patients or Other Participants: Ten uninjured healthy individuals (4M and 6F: 21.40 [3.03] y, 170.00 [7.93] cm, 71.03 [14.97] kg) participated. Intervention: None. Main Outcome Measures: Two investigators manually segmented 10 T1ρ ankle MR sequences using ITK-SNAP software to calculate T1ρ mean relaxation times and cartilage volumes. Each observer repeated the segmentation twice, with segmentations separated by 1 month. Intraobserver and interobserver reliability was determined using intraclass correlation coefficients (ICCs) with 95% confidence intervals and root mean square coefficient of variations (RMSCVs). Results: For T1ρ relaxation time, intraobserver (ICC = .994–.997, RMSCV = 1.31%–1.51%) and interobserver reliability (ICC = .990, RMSCV = 2.36%) was excellent for the overall talar dome. Excellent intraobserver (ICC = .975–.980, RMSCV = 3.88%–4.59%) and excellent interobserver reliability (ICC = .970, RMSCV = 5.13%) was noted for overall talar cartilage volume. Conclusions: The results demonstrate that manual segmentation of the entire talar dome from a T1ρ MR is reliable and repeatable.
Bernadette D. Buckley and Christopher J. Joyce
A 13-year-old female recreational soccer player presented with spontaneous left knee effusion approximately 2 weeks after the start of soccer season. Radiographic imaging was negative, and a complete blood count identified an increase in inflammatory markers. Additional two-tier testing confirmed a Lyme disease diagnosis, which was unusual for an athlete residing in the southeast region of the United States. The presentation of knee effusion, and subsequently Lyme arthritis, is a common clinical manifestation of late-stage Lyme disease. Early recognition of this infection and prompt treatment by a variety of specialists reduce the severity or chronicity of symptoms.
Hannah E. Wyatt, Gillian Weir, Carl Jewell, Richard E.A. van Emmerik, and Joseph Hamill
Coordination variability (CV) is commonly analyzed to understand dynamical qualities of human locomotion. The purpose of this study was to develop guidelines for the number of trials required to inform the calculation of a stable mean lower limb CV during overground locomotion. Three-dimensional lower limb kinematics were captured for 10 recreational runners performing 20 trials each of preferred and fixed speed walking and running. Stance phase CV was calculated for 9 segment and joint couplings using a modified vector coding technique. The number of trials required to achieve a CV mean within 10% of 20 strides average was determined for each coupling and individual. The statistical outputs of mode (walking vs running) and speed (preferred vs fixed) were compared when informed by differing numbers of trials. A minimum of 11 trials were required for stable mean stance phase CV. With fewer than 11 trials, CV was underestimated and led to an oversight of significant differences between mode and speed. Future overground locomotion CV research in healthy populations using a vector coding approach should use 11 trials as a standard minimum. Researchers should be aware of the notable consequences of an insufficient number of trials for overall study findings.
Kyndell R. Crowell, Ryan D. Nokes, and Nicole L. Cosby
Clinical Scenario: Dynamic knee valgus (DKV) is a mechanical alteration in the knee that leads to increased risk of injury. Weakness of hip musculature in hip abduction (HABD), extension (HEXT), and external rotation (HER) may contribute to increased DKV in single-leg landing tasks. Focused Clinical Question: Is decreased hip strength associated with an increase in DKV during a single-leg landing task in collegiate female athletes? Summary of Key Findings: Three studies were included: One randomized control trial (RCT), one cohort study, and one case-control. All three studies found that decreases in HABD and HER strength contributed to increased DKV during single-leg landing tasks. One study also found that the hip extensors contribute to controlling hip adduction, a common factor in many mechanisms of injuries. These three studies recommended strengthening HABD, HEXT, and HER to decrease DKV and reduce the risk of injury at the knee. Clinical Bottom Line: Weak HABD, HEXT, and HER contribute to increased DKV in college female athletes, but strengthening HABD, HEXT, and HER can lead to decreases in DKV and, overall, reduce the risk of injury at the knee. Strength of Recommendation: These articles were graded with a level of evidence of III or higher, giving a grade of B strength of recommendation that weak HABD, HEXT, and HER are associated with increased DKV in collegiate female athletes.
Hiromichi Usuki, Nealy Grandgenett, Sofia Jawed-Wessel, Adam B. Rosen, and Melanie L. McGrath
While Brazilian jiu-jitsu (BJJ) has a rate of injury similar to other combat sports, there is little information on the types of injuries sustained by BJJ athletes. The purpose of this study was to assess demographic information, participation rates, injuries, and medical care in BJJ athletes over a 12-month period. Seventy-eight athletes (75.0%) reported 136 injuries in the past year; however, medical attention was only sought for 59 (43.4%) of those injuries. No significant association was found between each demographic variable and injury prevalence. Despite the fact that a majority of BJJ athletes reported suffering an injury within the past year, slightly less than half of these injured athletes sought medical care. There was no difference in injury prevalence between belt ranks.
Kelly M. Cheever, W. Geoffrey Wright, Jane McDevitt, Michael Sitler, and Ryan T. Tierney
The objective of this study was to explore the correlation between preseason measures of cervical sensorimotor function and musculoskeletal injury rates across a contact sport season. The authors hypothesized that athletes with higher sensorimotor dysfunction at baseline would be more likely to suffer an injury. The authors further hypothesized that contact sport participation would lead to greater changes in cervical sensorimotor function across a sport season compared with noncontact controls. Forty-nine collegiate club athletes (26 rugby and 23 noncontact controls) participated in a cohort study. Low positive correlations between baseline sign and symptom severity (r = .383), and score (r = .344), and cervical joint position error (r = .385–.425) and time loss injury were observed. Combining sign and symptom severity score and the neck reposition error predicted musculoskeletal injury status with 80.8% accuracy (area under the curve = 0.80, p = .003). The results suggest preseason deficits in cervical sensorimotor function may be related to future musculoskeletal injury risk. Sign and symptom severity score, Neck Disability Index score, and cervical joint position error can help identify athletes requiring more comprehensive cervical spine assessment that may benefit from preventative intervention.