Inside Slant: Record year for ACL tears?

San Francisco 49ers linebacker NaVorro Bowman's gruesome left leg injury last weekend was, among other things, at least the 62nd instance of an NFL player tearing his ACL in a game or practice during the extended 2013 season.

Depending on how the NFL's injury tracking service officially classifies this season's injuries, it's quite possible 2013 will have brought two milestones:

  • The highest number of ACL injuries, suffered in either practices or games, on record.

  • The highest number of players placed on injured reserve because of any kind of knee injury in at least three years.

In an internal memo in December, the NFL noted there had been 30 torn ACLs in preseason and regular-season games through Week 13. That list, however, did not include injuries suffered during offseason practices, training camp or regular-season practices.

A number of independent bloggers have tracked ACL tears during that extended time period, beginning with offseason workouts last May. I've verified and worked with the list maintained by @ACLrecoveryCLUB, which is updated here with every name except Bowman's. It's possible there are more; these 62 are the ones I could verify.

The NFL has a vested interest in determining whether knee injuries rose as a result of new rules designed to eliminate helmet-to-helmet hits in games. The concern was that defenders would intentionally lower their aim to the knees, but with the exception of a few high-profile instances, that does not appear to have been the case.

Still, there are plenty of other ways to injure a knee and/or tear an ACL, and the league's competition committee will undoubtedly review the larger scale of numbers after the Super Bowl. Based on figures published by theMMQB.com, the highest total of ACL injuries in a season (including playoffs) on record is 56 in 2009 and 2012.

We'll await an official year-end tally before drawing any final conclusions. But the current count of 62 appears to have exceeded the previous high total.

What we do know: Based on research from ESPN Stats & Information, 125 players have been placed on injured reserve because of knee injuries -- tears, sprains, displaced kneecaps, etc. -- this season. That figure tops the totals in 2012 (121) and 2011 (93).

Injured reserve numbers aren't a complete reflection of knee health. But if you subscribe to the theory that limitations on offseason training in the 2011 collective bargaining agreement has left knees more vulnerable, then you've got a friend in these numbers.