The NHL, at least when it comes to injuries, exists in a world of mystery. Players are out with upper or lower body injuries, or sometimes even just a "body injury" when the coach is feeling extra coy, and recovery time frames aren't much more specific.
Given that, it's a minor miracle that Dallas Stars forward Tyler Seguin revealed what actually was injured when he was clipped by the Florida Panthers' Dmitry Kulikov one week ago. When Seguin met with the media on Friday, he said the injury was to his medial collateral ligament, or the MCL.
Here's the full interview for those who are already missing him:
So let's talk that cranky joint that holds your calf to your thigh, the knee.
The largest joint in the body, the knee is made of of four bones - the femur, tibia, fibula and patella (or kneecap), a whole bunch of cartilage of varying types, muscles, ligaments, tendons and other tissue. It's a complicated beast that doesn't take well to impact.
All of those components can be injured in some way or another, but what brings fear to the heart of every athlete are the injuries to the big ligaments that hold the femur to the bones of the lower leg - the medial and lateral collateral ligaments, and the anterior and posterior cruciate ligaments.
In simplified terms, ligaments are connective tissue that hold bone to bone. They stretch to a certain extent but can be stretched to a point they doesn't return immediately, leading to sprains or tears. Healing varies by ligament and injury.
Here's a handy picture from the National Institute of Health for illustration of where all the ligaments live:
The PCL and ACL form a cross-hatch on the inside of the knee, connecting the femur to the tibia. The ACL runs from the back of the femur to the front of the tibia and the PCL, which is significantly thicker and stronger than the ACL (and thus injured less often), from the front of the femur to the back of the tibia.
These are the ligaments, particularly the ACL, that tend to get hurt in head-on collisions where the knee hyperextends backwards. When they are completely torn, they are a no-expenses paid trip to surgery for repair. Even after surgery, the anatomical location and other complications means they are very slow to heal. And because the ACL and PCL provide the real forward and backward stability of the knee, there is also a psychological component to the recovery as well.
The MCL and LCL, on the other hand, provide support to keep the knee from slipping sideways. The MCL, as the name implies, is on the inside of the knee connecting the femur to the tibia while the LCL is on the outside connecting the femur to the smaller fibula. The MCL is much more commonly injured, often when the knee takes an impact from the outside and hyperextends towards the middle of the body. When you see NFL and college football linemen wearing knee braces, they're trying to protect their MCL's from exactly the same type of clip Seguin took.
That particular mechanism of injury is why people were speculating about MCL as soon as they saw the slow motion replays of Kulikov's clip. It's clear Seguin's knee flexes inward in a way it's not supposed to.
So that's the bad news. The good news is that unlike the cruciate ligaments, the collateral ligaments tend to heal relatively quickly and without surgery. And while they heal with scar tissue, the ability of the ligaments to bear load after the injury is not affected.
The timeline depends the nature of the injury and how the athlete's body responds to healing time. Grade I sprains of the MCL are usually two weeks or less to allows for the reduction of pain and swelling. There is no tear to the ligament at this grade, so the time allows for the reduction of swelling as well as the repair of any microtears in the ligament itself.
Grade II sprains (or partial tears of the ligament) and Grade III sprains (complete tears of the ligament) take a while longer to heal, from two weeks at the short end to eight weeks at the long end for professional athletes with access to high-end rehabilitation.
The initial treatment is usually a brace, some anti-inflammatory painkillers and rest. As ligaments have a blood supply, there is a collection of fluid in the knee from the sprain that takes time to reabsorb, and that fluid causes pain and stiffness. That resting time for the pain to dissipate also gives the ligament time to knit itself back together securely. That helps counter the natural tendency to try and rush back. As the pain and stiffness works themselves out, the athlete can begin to rehab the knee for strength and range of motion.
For what its worth, Seguin also mentioned getting a second injection of "blood" into his knee in the interview. It's a guess, but I suspect that refers to the growing area of stem-cell treatment, where immature cells are injected into the knee to try and help aid in the healing of the knee tissue. It's an intriguing, new area of medicine where research is still ongoing. Results have been hard to quantify, but it certainly can't hurt.
[Ed. note: As one of our commenters points out, this could also be a reference to platlet-rich plasma therapy, where a patient's blood is centrifuged to concentrate the watery part of the blood [plasma] with platlets, which both help induce clotting as well as contain many chemicals called growth factors. Like stem-cell treatment, this is a new area of medicine with mixed trial results, but again, it couldn't hurt.]
Once the MCL does heal, however that may happen, many athletes continue to wear hinged knee braces when they return to play, and some keep them on for the rest of their careers. Jere Lehtinen wore a knee brace until he retired, and while I can't pinpoint the exact time he started to wear one, he did miss a month in 1997 with a knee ligament sprain. That screams potential MCL injury.
In a way, the Stars got lucky. Once Kulikov decided to go full submarine on Seguin's knees, an MCL sprain is probably the best possible outcome. While there is often a significant chunk of time off needed for healing, the long-term consequences of that type of injury is generally minor, especially compared to ACL tears or cartilage injures.