Anterior cruciate ligament (ACL) ruptures significantly impact athletes in terms of return to play and loss of long‐term quality of life. Before the onset of this study, understanding the mechanism ...of ACL injury was limited. Thus, the primary focus of this manuscript is to describe our multi‐faceted approach to uncovering the mechanism of noncontact ACL injury (NC‐ACLI) with the goal of developing preventive strategies. The initial qualitative analysis of ACL injury events revealed most (70%) injuries involve minimal to no contact and occurr during landing or deceleration maneuvers in team sports with a minor perturbation before the injury that may disrupt the neuromuscular system leading to poor body dynamics. A series of quantitative videotape studies demonstrated differences in leg and trunk positions at the time of NC‐ACLI in comparison to control subjects. Analysis of the faulty dynamics provoking NC‐ACLI, especially the flat‐footed landing component, supports the theory that an axial compressive force is the critical factor responsible for NC‐ACLI. Our magnetic resonance imaging study demonstrated the NC‐ACLI position was associated with a higher tibial slope, and joint contact occurring on the flat, anterior portion of the lateral femoral condyle versus the round, posterior aspect. Both anatomic conditions favor sliding (pivot shift) over rolling in the presence of an axial compressive force. Subsequent cadaveric studies supported axial compressive forces as the primary component of NC‐ACLI. Both a strong eccentric quadriceps contraction and knee abduction moments may increase the compressive force at the joint thereby lowering the axial threshold to injury. This manuscript summarizes the NC‐ACLI mechanism portion of the 2021 OREF Clinical Research Award.
Background:
Research on the cause of lateral patellar dislocation (LPD) has focused on trochlear morphologic parameters, joint alignment, and patellofemoral soft tissue forces. A paucity of ...information is available regarding how patellar morphologic parameters influence the risk for LPD.
Purpose/Hypothesis:
The purpose was to assess whether patellar morphology is a risk factor for recurrent LPD. It was hypothesized that (1) patients with recurrent LPD would have decreased patellar width and volume and (2) patellar morphologic parameters would accurately discriminate patients with recurrent LPD from controls.
Study Design:
Cohort study (diagnosis); Level of evidence, 3.
Methods:
A total of 21 adults with recurrent LPD (age, 29.7 ± 11.1 years; height, 170.8 ± 9.9 cm; weight, 76.1 ± 17.5 kg; 57% female) were compared with 21 sex- and height-matched controls (age, 27.2 ± 6.7 years; height, 172.0 ± 10.6 cm; weight, 71.1 ± 12.8 kg; 57% female). Three-dimensional axial fat-saturated magnetic resonance imaging scans were used to measure patellar medial, lateral, and total width; patellar volume; patellar medial and lateral facet length; the Wiberg index; and previously validated knee joint alignment and femoral shape measurements (eg, tibial tuberosity to trochlear groove distance, trochlear dysplasia).
Results:
The LPD group demonstrated reduced medial patellar width (Δ = −3.6 mm; P < .001) and medial facet length (Δ = −3.7 mm; P < .001) but no change in lateral width or facet length. This resulted in decreased total patellar width (Δ = −3.2 mm; P = .009), decreased patellar volume (Δ = −0.3 cm3; P = .025), and an increased Wiberg index (Δ = 0.05; P < .001). No significant differences were found for all other patellar shape measures between cohorts. Medial patellar width was the strongest single discriminator (83.3% accuracy) for recurrent LPD. Combining medial patellar width, patellofemoral tilt, and trochlear groove length increased the discrimination to 92.9%.
Conclusion:
The medial patellar width was significantly smaller in patients with recurrent LPD and was the single most accurate discriminator for recurrent LPD, even compared with traditional trochlear shape and joint alignment measures (eg, trochlear dysplasia, patella alta). Therefore, medial patellar morphology should be assessed in patients with LPD as a risk factor for recurrence and a potential means to improve treatment.
➤ Catastrophic injuries in U.S. high school and college athletes are rare but devastating injuries.➤ Catastrophic sports injuries are classified as either traumatic, caused by direct contact during ...sports participation, or nontraumatic, associated with exertion while participating in a sport.➤ Football is associated with the greatest number of traumatic and nontraumatic catastrophic injuries for male athletes, whereas cheerleading has the highest number of traumatic catastrophic injuries and basketball has the highest number of nontraumatic catastrophic injuries for female athletes.➤ The incidence of traumatic catastrophic injuries for all sports has declined over the past 40 years, due to effective rule changes, especially in football, pole-vaulting, cheerleading, ice hockey, and rugby. Further research is necessary to reduce the incidence of structural brain injury in contact sports such as football.➤ The incidence of nontraumatic catastrophic injuries has increased over the last 40 years and requires additional research and preventive measures. Avoiding overexertion during training, confirming sickle cell trait status in high school athletes during the preparticipation physical examination, and developing cost-effective screening tools for cardiac abnormalities are critical next steps.
Heat-Related Illness in Athletes Howe, Allyson S.; Boden, Barry P.
The American journal of sports medicine,
08/2007, Letnik:
35, Številka:
8
Journal Article
Recenzirano
Heat stroke in athletes is entirely preventable. Exertional heat illness is generally the result of increased heat production
and impaired dissipation of heat. It should be treated aggressively to ...avoid life-threatening complications. The continuum
of heat illness includes mild disease (heat edema, heat rash, heat cramps, heat syncope), heat exhaustion, and the most severe
form, potentially life-threatening heat stroke. Heat exhaustion typically presents with dizziness, malaise, nausea, and vomiting,
or excessive fatigue with accompanying mild temperature elevations. The condition can progress to heat stroke without treatment.
Heat stroke is the most severe form of heat illness and is characterized by core temperature >104°F with mental status changes.
Recognition of an athlete with heat illness in its early stages and initiation of treatment will prevent morbidity and mortality
from heat stroke. Risk factors for heat illness include dehydration, obesity, concurrent febrile illness, alcohol consumption,
extremes of age, sickle cell trait, and supplement use. Proper education of coaches and athletes, identification of high-risk
athletes, concentration on preventative hydration, acclimatization techniques, and appropriate monitoring of athletes for
heat-related events are important ways to prevent heat stroke. Treatment of heat illness focuses on rapid cooling. Heat illness
is commonly seen by sideline medical staff, especially during the late spring and summer months when temperature and humidity
are high. This review presents a comprehensive list of heat illnesses with a focus on sideline treatments and prevention of
heat illness for the team medical staff.
Keywords:
heat stroke
heat exhaustion
dehydration
prevention
Sports participation is a leading cause of catastrophic cervical spine injury (CSI) in the United States. Appropriate prehospital care for athletes with suspected CSIs should be available at all ...levels of sport. Planning the process of transport for home venues before the start of the season and ensuring that a medical time out occurs at home and away games can reduce complications of transport decisions on the field of play and expedite transport of the spine-injured athlete.
Background: Recent studies have demonstrated that trunk control likely plays a role in anterior cruciate ligament (ACL) injury. Yet, the majority of ACL research remains focused on the lower limb, ...with limited information on the trunk position at the time of injury.
Hypotheses: Athletes experiencing a noncontact ACL injury after a 1-legged landing position their center of mass (COM) more posterior from the base of support (BOS) at initial ground contact in comparison with uninjured athletes. The distance from the COM to the BOS (COM_BOS) is larger in female, as compared with male, athletes during 1-legged landing.
Study Design: Case control study; Level of evidence, 3.
Methods: Movie captures of 20 athletes performing a 1-legged landing maneuver resulting in a torn ACL were compared with matched (for gender, sport, and activity just before landing) movie captures of 20 athletes performing a similar maneuver that did not result in an ACL disruption (controls). The COM_BOS, trunkG angle, and limbG angle (both relative to the gravity vector) were measured in the sagittal plane at initial ground-foot contact. A 2-way ANOVA (injury status × gender) was used to examine the hypotheses.
Results: There was a significant difference in all 3 measures based on injury status but not on gender. The COM_BOS, normalized by femur length, and limbG angle were greater (Δ = 0.9, P < .001 and Δ = 16°, P = .004, respectively), and the trunkG angle was smaller (Δ = 12°, P = .016) in the participants who sustained an ACL injury as compared with controls. The average COM was calculated as 38 cm more posterior relative to the BOS in the participants who sustained an ACL injury as compared with controls.
Conclusion: Landing with the COM far posterior to the BOS may be a risk factor for noncontact ACL injury and potentially can be addressed in prevention programs.
Background
Most anterior cruciate ligament research is limited to variables at the knee joint and is performed in the laboratory setting, often with subjects postinjury. There is a paucity of ...information on the position of the hip and ankle during noncontact anterior cruciate ligament injury.
Hypothesis
When landing after maneuvers, athletes with anterior cruciate ligament injury (subjects) show a more flatfooted profile and more hip flexion than uninjured athletes (controls).
Study Design
Case control study; Level of evidence, 3.
Methods
Data from 29 videos of subjects were compared with data from 27 videos of controls performing similar maneuvers. Joint angles were analyzed in 5 sequential frames in sagittal or coronal planes, starting with initial ground-foot contact. Hip, knee, and ankle joint angles were measured in each sequence in the sagittal plane and hip and knee angles in the coronal plane with computer software. The portion of the foot first touching the ground and the number of sequences required for complete foot-ground contact were assessed. Significance was set at P <. 05.
Results
In sagittal views, controls first contacted the ground with the forefoot; subjects had first ground contact with the hindfoot or entirely flatfooted, attained the flatfoot position significantly sooner, had significantly less plantar-flexed ankle angles at initial contact, and had a significantly larger mean hip flexion angle at the first 3 frames. In coronal views, no significant differences in knee abduction (initial contact) or hip abduction angle were found between groups; knee abduction was relatively unchanged in controls but progressed in subjects.
Conclusion
Initial ground contact flatfooted or with the hindfoot, knee abduction and increased hip flexion may be risk factors for anterior cruciate ligament injury.
Background:
Fatalities in football are rare but tragic events.
Purpose:
The purpose was to describe the causes of fatalities in high school and college football players and potentially provide ...preventive strategies.
Study Design:
Descriptive epidemiology study.
Methods:
We reviewed the 243 football fatalities reported to the National Center for Catastrophic Sports Injury Research from July 1990 through June 2010.
Results:
Football fatalities averaged 12.2 per year, or 1 per 100,000 participants. There were 164 indirect (systemic) fatalities (average, 8.2 annually or 0.7 per 100,000 participants) and 79 direct (traumatic) fatalities (average, 4.0 annually or 0.3 per 100,000 participants). Indirect fatalities were 2.1 times more common than direct fatalities. The risk of a fatality in college compared with high school football players was 2.8 (95% CI, 0.7-8.2) times higher for all fatalities, 3.6 (95% CI, 2.5-5.3) times higher for indirect events, 1.4 (95% CI, 0.6-3.0) times higher for direct injuries, 3.8 (95% CI, 1.8-8.3) times higher for heat illness, and 66 (95% CI, 14.4-308) times higher for sickle cell trait (SCT) fatalities. Most indirect events occurred in practice sessions; preseason practices and intense conditioning sessions were vulnerable periods for athletes to develop heat illness or SCT fatalities, respectively. In contrast, most brain fatalities occurred during games. The odds of a fatality during the second decade, compared with the first decade of the study, were 9.7 (95% CI, 1.2-75.9) for SCT, 1.5 (95% CI, 0.8-2.9) for heat illness, 1.1 (95% CI, 0.8-1.7) for cardiac fatalities, and 0.7 (95% CI, 0.4-1.2) for brain fatalities. The most common causes of fatalities were cardiac failure (n = 100, 41.2%), brain injury (n = 62, 25.5%), heat illness (n = 38, 15.6%), SCT (n = 11, 4.5%), asthma and commotio cordis (n = 7 each, 2.9% each), embolism/blood clot (n = 5, 2.1%), cervical fracture (n = 4, 1.7%), and intra-abdominal injury, infection, and lightning (n = 3, 1.2% each).
Conclusion:
High school and college football have approximately 12 fatalities annually with indirect systemic causes being twice as common as direct blunt trauma. The most common causes are cardiac failure, brain injury, and heat illness. The incidence of fatalities is much higher at the college level for most injuries other than brain injuries, which were only slightly more common at the college level. The risk of SCT, heat-related, and cardiac deaths increased during the second decade of the study, indicating these conditions require a greater emphasis on diagnosis, treatment, and prevention.
Background
The mechanisms of anterior cruciate ligament injury in basketball are not well defined.
Purpose
To describe the mechanisms of anterior cruciate ligament injury in basketball based on ...videos of injury situations.
Study Design
Case series; Level of evidence, 4.
Methods
Six international experts performed visual inspection analyses of 39 videos (17 male and 22 female players) of anterior cruciate ligament injury situations from high school, college, and professional basketball games. Two predefined time points were analyzed: initial ground contact and 50 milliseconds later. The analysts were asked to assess the playing situation, player behavior, and joint kinematics.
Results
There was contact at the assumed time of injury in 11 of the 39 cases (5 male and 6 female players). Four of these cases were direct blows to the knee, all in men. Eleven of the 22 female cases were collisions, or the player was pushed by an opponent before the time of injury. The estimated time of injury, based on the group median, ranged from 17 to 50 milliseconds after initial ground contact. The mean knee flexion angle was higher in female than in male players, both at initial contact (15° vs 9°, P = .034) and at 50 milliseconds later (27° vs 19°, P = .042). Valgus knee collapse occurred more frequently in female players than in male players (relative risk, 5.3; P = .002).
Conclusion
Female players landed with significantly more knee and hip flexion and had a 5.3 times higher relative risk of sustaining a valgus collapse than did male players. Movement patterns were frequently perturbed by opponents.
Clinical Relevance
Preventive programs to enhance knee control should focus on avoiding valgus motion and include distractions resembling those seen in match situations.
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