A picture of the knee ligaments looking from behind: Tibial Collateral Ligament = MCL and Fibular Collateral Ligament = LCL
This is a guest post by Jonathan Gelber, M.D. founder of fightmedicine.net.
Famed trainer John Hackleman recently described Dan Henderson to me as "one of the toughest humans ever". Yet, a partial tear of the Medial Collateral Ligament (MCL) did what very few people have ever done - both stop Dan Henderson from fighting and cancel an entire UFC event (UFC 151). Beyond that, Jon Jones' reputation after refusing to fight Chael Sonnen may continue to be injured long after Dan straps on his gloves for his return match. All from a partial tear of a knee ligament.
First, what is a ligament? Ligaments connect one bone to the other. This is in contrast to tendons, which are the tapering ends of muscles and connect the muscle to the bone for movement. By connecting bones together, ligaments act as mostly static stabilizers of joints. Static stabilizers such as ligaments or the geometry of the bones help to stabilize a joint before the dynamic stabilizers have a chance to act. Dynamic stabilizers, which include large muscle groups, act to stabilize the joint through motion.
The knee has four main stabilizing ligaments. The most famous of all of them is the Anterior Cruciate Ligament (ACL) which is in the center of the knee. Its importance was outlined in a previous article from my website fightmedicine.net. Crossing the ACL in the middle of the knee is the Posterior Cruciate Ligament (PCL). On either side of the knee are collateral ligaments: the Medial Collateral Ligament (Medial = Inner) and Lateral Collateral Ligament (Lateral = Outer). The MCL is sometimes called the Tibial Collateral Ligament and the LCL is sometime called the Fibular Collateral Ligament. These collateral ligaments are important in stabilizing the knee when a force is directed from either the inside or outside of the knee. If the knee is hit from the outside (lateral) aspect of the knee, such as someone diving in for a tackle, the Lateral Collateral Ligament (LCL) compresses and the MCL stretches, making the MCL the important stabilizer of the knee at that moment. The opposite is true if the knee is hit from a force on the inner side (medial) side of the knee and directed laterally (outside); there, the LCL becomes tight and acts as the stabilizing ligament.
From what we have heard from Henderson's camp, he has suffered a partial tear of his MCL. When most people hear about a ligament injury of the knee, they think of an ACL rupture which is often a career ending or changing injury. This is because the ACL is not surrounded by a sheath since it is inside the knee joint. Because the ACL lacks this sheath, a hematoma cannot form and stabilize after an injury. Without a hematoma acting as a scaffold, new cells cannot populate the injured site and create repaired tissue. The MCL, on the other hand, does have this sheath as it lies on the outside of the knee joint. As a result, a hematoma can form and the ligament can usually repair itself without surgery.
Tears of ligaments are visualized using Magnetic Resonance Imaging (MRI) because soft tissue cannot show up on xrays. Using an MRI and a physical exam, the level of MCL tearing can be classified. Grade I tears only involve a few fibers of the ligament, resulting in localized tenderness but no instability. Grade II tears occur with disruption of more fibers and result in more generalized tenderness. There is usually either no instability or some instability at 30 degrees of knee flexion (0 degrees is a straight knee) but no instability at 0 degrees of flexion. A Grade III tear is a complete disruption of the ligament, with resultant instability at both 0 and 30 degrees of flexion.
Additional ligaments are often injured along with the MCL, most commonly the ACL. More than 7 mm of looseness on exam is thought to signify additional injury to the ACL, which can be confirmed on MRI or physical exam. The MCL is composed of two layers, a superficial and deep. The deep fibers often attach to the medial meniscus (the C-shaped rings of cartilage in the knee that act as shock absorbers), so injury to the MCL may also lead to a torn meniscus.
As Henderson himself has said, it appears he has a partial tear of his MCL, which would mean it is either a Grade I or Grade II sprain. While there are no hard rules when it comes to treating partial MCL tears, some general guidelines are used. Grade I sprains usually don't need to do anything other than let pain be their guide. If it hurts, back off. If not, go ahead. Grade II sprains will usually get a hinged knee brace locked in full extension for about 2 weeks and then unlock the brace. The brace acts as a lateral support. Athletes can usually return to their sport in about 4-6 weeks. The more severe Grade III, or complete disruption needs a hinged knee brace locked for 6 weeks and it can take at least 3 months for full recovery. There are also rare circumstances when a Grade III needs surgery such as when a piece of bone pulls off with the ligament or the ligament gets trapped inside the knee joint.
While it appears Dan will do just fine with his knee brace and rest, the phantom of testosterone replacement therapy (TRT) hangs over everything that he does. Henderson was granted a therapeutic use exemption (TUE) by the Nevada State Athletic Commission due to low testosterone levels. Many people consider TRT as a performance enhancing drug (PED) and thus will undoubtedly ask the question how TRT and Dan's latest injury will interact. For a primer on TRT, see this article from fightmedicine.net.
As far as testosterone or even anabolic steroids in general, there are no studies to suggest that they help ligament (or tendon) healing. In fact, most studies show that anabolic steroids lead to degeneration of tendon-forming cells when cultured in a lab. Furthermore, there are many case reports documenting tendon rupture and the occasional ligament rupture after anabolic steroid use. One may argue that testosterone is not an anabolic steroid, but its metabolic effects are practically the same. According to Don Catlin, one of the founding fathers of PED testing and research, the gut-feeling of the majority of those that work with and understand the effects of testosterone and anabolic steroids on a cellular level is that, while the literature does not suggest one thing or the other, the use of anabolic steroids and testosterone is deleterious to tendons and ligaments.
A partial tear of the MCL is just a minor bump in the road to the legendary Dan Henderson. He will recover and he will get back in the ring or Octagon and continue to fight. What remains to be seen is if he can ever stand clear of the TRT shadow and if Jon Jones will overcome his major PR injury.
Jonathan Gelber, M.D. is licensed to practice in the State of California and is founder of fightmedicine.net where he brings together the MMA and medical communities. You can follow him on Twitter: @FightMedicine. Or find him on Facebook at FightMedicine.