Video Analysis of Anterior Cruciate Ligament Tears in Professional American Football Athletes.

BACKGROUND: Anterior cruciate ligament (ACL) injuries are prevalent in contact sports that feature cutting and pivoting, such as American football. These injuries typically require surgical treatment, can result in significant missed time from competition, and may have deleterious long-term effects on an athlete's playing career and health. While the majority of ACL tears in other sports have been shown to occur from a noncontact mechanism, it stands to reason that a significant number of ACL tears in American football would occur after contact, given the nature of the sport. Hypothesis/Purpose: The purpose was to describe the mechanism, playing situation, and lower extremity limb position associated with ACL injuries in professional American football players through video analysis to test the hypothesis that a majority of injuries occur via a contact mechanism. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective cohort of National Football League (NFL) players with ACL injuries from 3 consecutive seasons (2013-2016) was populated by searching publicly available online databases and other traditional media sources. Of 156 ACL injuries identified, 77 occurred during the regular season and playoffs, with video analysis available for 69 injuries. The video of each injury was independently viewed by 2 reviewers to determine the nature of the injury (ie, whether it occurred via a noncontact mechanism), the position of the lower extremity, and the football activity at the time of injury. Playing surface, player position, and time that the injury occurred were also recorded. RESULTS: Contrary to our hypothesis, the majority of ACL injuries occurred via a noncontact mechanism (50 of 69, 72.5%), with the exception of injury to offensive linemen, who had a noncontact mechanism in only 20% of injuries. For noncontact injuries, the most common football activity at the time of injury was pivoting/cutting, and the most common position of the injured extremity included hip abduction/flexion, early knee flexion/abduction, and foot abduction/external rotation. There was no association between injury mechanism and time of injury or playing surface in this cohort. CONCLUSION: In this study of players in the NFL, the majority of ACL tears involved a noncontact mechanism, with the lower extremity exhibiting a dynamic valgus moment at the knee. These findings suggest that ACL injury prevention programs may reduce the risk of noncontact ACL tears in American football players.

Elbow arthroscopy: capitellar osteochondritis dissecans and radiocapitellar plica.

The combination of excessive radiocapitellar compressive forces and the limited vascularity of the capitellum are responsible for the development of osteochondritis dissecans. Repetitive compressive forces are generated by throwing or racket swinging motions or from constant axial compressive loads on the elbow, which are common in athletes such as gymnasts. Symptoms include activity-associated pain and stiffness. Physical examination findings show tenderness over the radiocapitellar joint and, commonly, loss of extension. Plain radiographs may show flattening and sclerosis of the capitellum, lucencies, and possibly intra-articular loose bodies. MRI can detect bone edema early in the disease process and further delineate the extent of the injury. The management of osteochondritis dissecans lesions is primarily based on the demands of the patient, the size and location of the lesion, and the status and stability of the overlying cartilage. Possible treatments include transarticular drilling; removing detached fragments or loose bodies, followed by drilling; and mosaicplasty. Radiocapitellar plica can cause chondromalacic changes on the radial head and capitellum, with symptoms including painful clicking and effusions. Arthroscopic plica resection is indicated when nonsurgical treatment fails.