imagine a door hinge and it is relatively similar to the way the knee swings anterior to posterior. Synovial joints are the most common types of joints. They are characterized by being highly moveable and all having synovial capsules that surround the joint and secrete synovial fluid which is used for lubrication between the bones. The major muscles that allow the knee to move are the femoris group, also known as the quadriceps, the gastrocnemius or calf muscle and the hamstring muscle group. All of these muscles aid in the movement of the knee joint. The femoris group aids in extension and the hamstring group aids in flexion. Each has a protagonist, or the muscle doing the action, an antagonist, the muscle that moves in the opposite direction and a synergist which is the stabilizing muscle helping the protagonist muscle. The MCL is one of the most common injuries in the knee.
It can even be a career ending injury in professional and collegiate sports. The main function of the knee besides holding everything in place is to make sure that the knee doesn’t hyperextend medially. It also aids in the stabilization of the knee and allowing it to rotate. If you plant your foot and stabilize your other joints you will notice you can still rotate on the axis of your knee slightly. The main reason it is only slightly is because of the MCL and LCL. Injury can come in many forms to the MCL. Deceleration and then acceleration in another direction especially laterally is a large culprit to MCL strains, sprains and tears. The other most common way to injure the MCL is when an outside force is applied to the opposing side causing the movement that the MCL is there to stop. An example would be a football player catching a helmet to the lateral side of the knee causing it to hyperextend medially. (see figure
1.1) People often use Sprain and strain interchangeably. They are not the same thing. A sprain is when you tear or stretch a ligament. A strain is when you stretch or tear the tendons or muscles. Thus, you cannot sprain your bicep or any other muscle or tendon group and vice versa, you cannot strain your MCL etc. There are 3 grades to measure the severity of a sprain. A grade one sprain is where the ligaments are slightly stretched or very small tears, usually a few days to a week and half to heal. A grade two sprain is where the ligaments may be partially torn, approximately two to four weeks for proper healing. A grade three sprain is where a ligament is completely torn. This is the worst case scenario, usually four to eight weeks of heal time however the ACL causes further healing time and surgery may be indicated. (See figure 1.2) Some signs and symptoms you might see from an MCL sprain include swelling and redness at the site as well as decreased range of motion and stiffness. The patient may complain of pain and tenderness at the site. Sprains on average usually take six weeks to heal. Ligaments have very poor blood flow and so they take a longer time to heal than other tissues. They usually treat by managing the pain and then managing inflammation so they can begin to stabilize the knee via a knee immobilizer. The key in the begging is the acronym R.I.C.E, Rest, Ice, Compress and Elevate. Pain relievers and anti-inflammatories can be prescribed to help with the pain and swelling. Usually the pain and swelling will dissipate in the first 72 hours. After that 72 hour period, rehabilitation can begin. Crutches are usually prescribed so as to limit or eliminate the weight bearing of that leg. An orthopedist can prescribe a special knee brace. That allows the anterior to posterior movement of the knee but a metal brace prevents the side to side motion so the MCL can heal. Slowly exercises will be brought into everyday regimen to strengthen the synergist muscles as well as the ligament. The key is to move slowly and not over exert. We use the patients tolerance and range of motion as progress points after each rehabilitation session. As mentioned earlier if the ACL is involved in the damage of the MCL surgery may be indicated. If we think about the four main ligaments as points holding the knee together we can see why this is so. If one point (the MCL) is damaged three other points are still holding it together. Anterior to posterior movement is not inhibited. If the ACL is damaged then no movement may occur. This is why surgery may be indicated. Surgery however is very rare for the MCL itself. If the ligament is torn closer to the bones the surgeon will go in and reattach it. If it is torn in the middle then he or she will sew the two ends back together. The surgery when it is done is through a small incision rather than arthroscopically because the ligament isn’t inside the knee joint. Rehabilitation for an MCL injury is greatly outlined in four phases for the grades 2+ sprains. It is very important to make sure that the ends of these ligaments are left to heal properly so immobilization is key. In phase one which immediately follows the injury up until 4 weeks post injury, we start with cold compresses and rest with non weight bearing up until week two. Crutches can be used as well as knee brace for immobilization. After week two some weight bearing can be done as pain allows. Phase two starts after week four and lasts about two weeks. This phase is to eliminate all swelling and get to full weight bearing, full range of motion and almost full strength. Cold therapy continues and range of motion exercises should be continued coupled with isometric strength training. Swimming is also a good option in phase two. Phase three starts after week 6 from the initial injury and lasts up to four weeks. Sports massage techniques can be applied to the knee during this time. Light jogging as pain allows is also started by week 10. After week six is also the mark that we can begin running, no sooner. After week eight lateral movements should start to be incorporated into the rehab program. After week 10 plyometric drills can be incorporated into the rehab as well so long as it can be tolerated by the patient. Phase four begins after week 10 from initial injury and last about 2 to 4 weeks. By this time, the goal Is to return to the athletes sport specific exercises without pain and to have full strength and mobility. These exercises should be brought on slowly and as tolerated by the patient. Returning to activity is largely based on the patients overall feelings on the stability of the knee. Of course returning to each sport would require different levels of participation. If a Doctor and an athletic trainer release the patient to return to play, they are confident that that player has enough range of motion, stability and strength to meet the standards that will be asked of the patient within the sport. If certain check points are not met during rehabilitation the athlete may be held from returning to play until the Doctor is satisfied with the results. Protective equipment is not usually recommended especially during contact sports as this just presents a target for other players. Instead if a brace is needed the athlete should withhold from playing until full confidence is restored into the knee. If a brace is needed it would be wise to put it underneath the uniform so as not to display a weak spot. Prevention of this injury would include strengthening of the synergist muscles as well as the quadriceps so that the brunt of the work isn’t being taken by the ligament itself. Proper body mechanics when cutting and changing direction as the athlete runs is also a large part in preventing injury. Of course, stretching lightly before any exercise in a dynamic vs. static manner will help with the warming up of the ligament so it is ready to do its job.