In Sunday's Eagles game against the Minnesota Vikings, cornerback Ron Brooks went down with a non-contact right knee injury in the first half.  The Eagles have confirmed that he suffered a ruptured quadriceps tendon that will require surgery, making it likely that he will be out for the season.

Quadriceps tendon injuries occur when the tendon tears away from the patella (knee cap). It typically result from a forceful eccentric load where the muscle is resisting bending of the knee. They commonly occur in males over 40 during sporting activities or resulting from a fall.  Other potential non-traumatic causes include tendinosis, use of corticosteroids, or the use of specific antibiotics (fluoroquinolones). However, this injury is very rare in football.

While Achilles tendon ruptures are becoming more frequent in the NFL, ruptures to the quadriceps tendon are hardly seen.  A 2013 study by Boublik in the American Journal of Sports Medicine looked at quadriceps tendon ruptures in the NFL over a 10-year period starting in 1994. During that time, the study found only 14 quad tendon ruptures in 10 years. By comparison, NFL injury rates for Achilles tendon ruptures are between 4-10 per year with the 2015-16 season seeing more than 15.

The injury can vary in severity from a small partial tear that heals without surgery, to a larger partial tear or complete rupture, both of which require surgery.

Recovery from a ruptured quadriceps tendon can be difficult, particularly for professional athletes.  There are many factors that can influence return to play including partial versus complete tear, age of the player, years in the league, and pre-jury performance (starter vs substitue).

Boublik et al found in their studies that only 50 percent of the athletes with this injury returned to play. By comparison, 80 percent of athletes return to play after a patellar tendon rupture, while another study by Parekh et al in 2009 found that 70 percent of Achilles tendon ruptures return sports.

Only time will tell if Ron Brooks will return to his pre-injury level of play. Hopefully, he will prove the statistics wrong.

Read more Sports Doc for Sports Medicine and Fitness.