New York Giants linebacker Michael Boley is expected to be sidelined for a month after undergoing arthroscopic knee surgery on Tuesday to "repair" a "partially" torn meniscus.
The injury apparently happened during this past Sunday's game against Kansas City, although Boley did not miss a snap and made five solo tackles with one sack.
Signed as a free agent in February after four years with Atlanta, Boley played three games this season and is the team's third-leading tackler with 15 stops, including 13 solo.
Quiz: If you were in the NFL, what would you rather have: a meniscus tear or an ACL tear?
First, a lesson in Sports Medicine History and Nomenclature 101:
There are two types of cartilage in the knee. The articular cartilage is the lining of the joint and the meniscus are the "crescent shaped cushions" on the medial and lateral (inner and outer aspect). The meniscus plays an important role in joint stability, force transmission, and lubrication.
Acute tears occur from flexion twisting injuries. Location, pattern, and stability of the tear are important characteristics. Blood flows only to the outer edges so tears of the inner aspect do not heal, even with surgery.
A tear can further be classified as complete or incomplete, whereby a complete tear, less common, is one in which a piece is thoroughly separated or completely torn off from the rest of the meniscus.
Hard to believe but the meniscus was once thought to be of little function and in the 1970s, tears were treated with complete removal of the meniscus (a meniscectomy). Bone on bone arthritis and bow legged or knock kneed deformity quickly ensued, depending if the medial or lateral meniscus was removed.
After this grave mistake, a "partial" meniscectomy became the standard of care, whereby only the part of the meniscus with the tear was shaved down to "clean" edges.
The severity of post partial meniscectomy arthritic changes is dependent on how much meniscus is shaved away; take away more, the more arthritis you get. Return to play can occur in 4-6 weeks.
Repair then is the preferred treatment whereby the tear is sutured back together without removal; but only certain tears located in the outer peripheral vascular region are amenable to repair and most do not occur here. Return to play after a repair is usually 4-6 months.
So what did Boley most likely have then? A partial meniscectomy.
The ACL (anterior cruciate ligament) is one of the ligaments that connect the femur to the tibia that provides stability to the knee joint. ACLs can partially tear (strain) but usually rupture (completely tear) and leave the athlete with an unstable or loose knee that buckles under stress of pivoting or planting.
ACLs are NOT repaired (the two ends can’t be tied back together) they are reconstructed. A reconstruction involves drilling a tunnel through the femur and tibia and placing a "new" "ligament" made from the athlete’s patella tendon or hamstring tendon (cut and removed) or from a cadaver graft (ligament removed from a dead person).
ACL ruptures usually cause bone contusions or bruises with the femur impacting the tibia. Return to play after an ACL reconstruction is usually 6-9 months.
So if you were in the NFL, what would you rather have: a meniscus tear and meniscectomy or an ACL rupture and reconstruction?
According to a study presented at the American Orthopaedic Society for Sports Medicine 35th Annual Meeting in July, you would rather have a meniscectomy.
The study evaluated the injury history and career statistics of NFL players who entered the league from 1987 to 2000, matching 54 athletes with a history of partial meniscectomy, 29 with a history of ACL reconstruction and 11 with a history of both to a control group of athletes with no previous injuries matched according to position, year drafted, and additional history.
Compared with controls who had no surgeries, players with isolated meniscectomy had careers that were approximately 1.5 years shorter (5.6 years vs 7.0 years; P = .03), and played 23 fewer games (62 vs. 85; P = .02).
Athletes who underwent surgery for both injuries had their careers shortened by nearly two years and 32 games.
Athletes with isolated ACL surgery, however, had no reduction in length of career or games played, compared with non-injured controls.
Surprised? Isolated meniscectomy worse than an ACL reconstruction?
Here is a closer look at the meniscus function:
The medial meniscus bears up to 50 percent of the load applied to the inside compartment of the knee. The lateral meniscus absorbs up to 80 percent of the load on the outside compartment of the knee.
While running, forces on the knee increase up to 6-8 times body weight. If the menisci are removed, the forces are no longer distributed over a wide area of the tibia.
Without the medial meniscus, the tibial contact area is decreased 50-70 percent which means the same forces from the femur are concentrated on a smaller surface area of the tibia.
When the lateral meniscus is removed, there is a 45-50 percent decrease in contact surface area, resulting in a 200-300 percent increase in contact pressure.
The end result is damage to the articular cartilage, or early degenerative arthritis and exit from the NFL.
Boley should be back in 4-6 weeks. But he may have a sooner retirement.
Marc Silberman, M.D.
New Jersey Sports Medicine and Performance Center