A quick turn followed by a pop of the knee may be the pinnacle of oh s*** moments. It’s a common occurrence in sporting events but also happens in everyday life.
It’s not always a grave situation—knees make creaky noises all the time and are quite robust— but the dreaded knee sprain does happen to many and is immediately impactful.
Despite the suddenness of the injury, it leaves prolonged aftermath. Not only painful and limiting, but the biggest struggle is the extended time to heal, and potentially the need for surgery.
In this article, we’ll help explain the knee sprain and guide a path to getting you back into action.
A knee sprain is the result of damage to the ligaments of the knee joint. There are several major ligaments, and a few lesser ones, that will be covered shortly.
A ligament is a fibrous tissue that attaches bone to bone. Ligaments are often confused with tendons, but it’s a different part of the anatomy.
If you want a full review of the knee and how everything ties together, check out our Quick Guide to Understanding How the Knee Works. But if you want to get straight to it, let’s focus specifically on the ligaments of the knee.
Understanding the difference between the types of tissue in the knee is important because it helps answer the usual question…
“How long will this take to heal?!!?”
The reason is due to blood flow! In general, the ligaments in our bodies have a poor blood supply. Bone has a great blood supply, the muscle has a great blood supply, but cartilage, tendons, and ligaments do not.
Without quick access to new blood, and therefore healing factors that our body uses to repair, it takes an extended time to heal those strained or sprained tissues.
SPRAIN VS. STRAIN VS. TEAR
Damage to the ligaments gets classified as either:
A sprain is when we overextend a ligament.
A tear is when we overextend, and the two pieces lose their connection.
(Note- A strain is another common orthopedic injury term, but this occurs when we overextend a tendon or muscle.)
All ligaments have a threshold of strength. Just like a rope has an amount of force that it can withstand when holding two objects together. And just like the rope, if a ligament gets stretched too quickly OR too hard, then it gets damaged.
Each ligament provides a specific restraint to prevent the knee from going too far in one direction. Here are the major ones and usual suspects when it comes to knee sprains:
- Anterior cruciate ligament (ACL) is commonly injured in field sports, volleyball, gymnastics, and skiing. Typically injuries occur by a hit to the side of the knee, or if there is a twisting motion with hyperextension at the knee.
- Posterior cruciate ligament (PCL) is most commonly injured in what is called the “dashboard” mechanism—when knees are bent to the chest (called hyperflexion) and the shin bone is pushed backward. This happens in a car crash (hence the name) or may also occur by getting tackled while the knee is bent.
- Medial collateral ligament (MCL) commonly injured in field and ice sports. This ligament protects the knee from bending inwards.
- Lateral collateral ligament (LCL) protects the knee from going out and is injured much less than the MCL.
- Medial patellofemoral ligament (MPFL) is a small but mighty ligament that helps to stabilize the knee cap in the groove over the knee. An injury to the MPFL is likely anytime there is a dislocation of the knee cap.
You have other ligaments in the knee, but you’re not as likely to injure them.
GRADING YOUR SPRAIN
Sprains are graded by the level of injury to the tissue. These grading systems vary for different ligaments in the body, but the most common scale for knee ligament injuries is I-III (least to worst.)
A grade I sprain occurs due to overstretching. It is considered a “mild” sprain and usually results in minor swelling and stiffness of the knee. Current evidence shows that a grade I sprain in the knee will heal and return to normal in anywhere from 4-8 weeks.
It’s a frustratingly long time for some “minor” stretching. But the blood supply issue pushes the healing time out longer than most people suspect. And since the knee is so crucial to getting around, even minor discomfort doesn’t go unnoticed.
A Grade II sprain means there is a small tear, but it’s not all the way through the ligament. At this time, it’s unknown how much those sprains truly heal, but it’s safe to assume that you can get back to your sport after some time off.
A Grade III sprain is equivalent to a full tear in which the ligament has torn apart from itself and don’t expect these to heal. Grade III sprains often undergo surgery, although there are currently many valid non-operative options.
DIAGNOSING YOUR KNEE SPRAIN
If you’ve been hit with a knee sprain, start by looking for the following Red Flags as a reason to seek further medical evaluation.
Medical Red Flags
- Knee gets “locked” in position- either bent or straight
- New onset of painful clicking or catching
- Feeling of instability or giving out
- Swelling that lasts >5 days
If you test out of all these and want to save time and money, then it’s fine to wait it out.
But, if you’re worried about your knee, get it checked out by a medical professional for peace of mind. It’s not really an emergency situation though, so no need to rush to the emergency room.
A physiotherapist is probably your best resource for the sake of time, cost, and a more comprehensive recovery plan when appropriate. Otherwise, a general practitioner or urgent care clinic can evaluate the issue and provide further recommendations, which are usually rest and anti-inflammatories, and potentially a referral for a sports medicine doctor (ref).
THE PROCESS FOR KNEE SPRAIN REHAB
If you’ve sprained your knee, the first question is likely: What should be done? It’s a simple, yet challenging task, and that is resting the injury.
Rest will be slightly different for each type of sprain, but in general, it means eliminating painful activities. In the best-case scenario, inflammation takes about 14 days to resolve. Thus, the rule of “if it hurts, don’t do it” is a safe bet to follow for 2 weeks. Trying to push through the pain will only bring further inflammation and ultimately slow healing time.
In total, you’re looking at a healing time of 6-8 weeks, but will be feeling better between 2-4 weeks. You will notice a reduction in swelling, and your range of motion will return to normal. You’ll feel that it’s time to get back to life—unfortunately, it’s not done healing.
It’s in the window of weeks 2-4 that people run into issues because they jump right back into their previous activity level. Even though the knee feels better, it’s still missing some stability, which increases the risk of hurting the same ligament again. If not something worse!
It’s during these weeks that a properly structured exercise plan becomes super important.
Low impact exercises targeting the glutes, core, and leg muscles will keep those muscles engaged, while healing occurs. This makes it easier to return to full activity, and potentially even solving some of the underlying strength issues that caused the knee sprain to happen.
If you need help with this, we walk you through everything in our 30-Day Knee Fix.
PREVENTING KNEE SPRAINS
As Ben Franklin once said, “An ounce of prevention is worth a pound of cure.” And considering the time and limitation caused by a knee sprain, an effort towards prevention is worth it. That’s especially true if you’re at higher risk, like in a sport with lots of contact or cutting.
When it comes to knee sprains, there are some things you can’t control. These are known as non-modifiable risk factors and include items such as:
- Ligament Size (some people just have smaller ligaments)
- Gender (women are at higher risk of knee sprains)
- Physical requirements of a sport or task (for example, soccer players are at higher risk of knee sprains than bowlers.)
- Background or history of training (previous time spent working with a strength coach)
Yet there are still things you can do to reduce the risk of knee sprains.
Building the strength of your muscles can help reduce the risk of a knee injury.
The knee is a rather simple joint—which flexes and extends—using the ligaments to keep it along its tracks. A blow to the knee can knock it out of place damaging the ligaments, or forces of just bodyweight moving in an awkward direction can strain a ligament as well.
That’s where strength and stability come into play for protecting the knee joint. Strong muscles slow the body and effectively transfer forces.
For example, the picture above shows the common mechanics for non-contact ACL tears. Someone with weak external rotators is 8x more likely to injure their ACL than someone who isn’t (ref). That’s because the external rotators (AKA- the glutes) help to control the position of the knee when landing and changing direction without overloading the ACL.
Speed and Timing
Again, speed is an essential component behind injuries to the ligaments as well. You could demonstrate the above position slowly and have no risk of injury, but if you got pushed that way, things could easily go wrong.
Again, we prevent entering these positions through the control of the hip extensors, abductors, and extensors. But it’s not enough to just have the strength of the muscles, it’s also essential to engage them quickly and with the right timing.
For that reason, practice and training of explosive cutting and jumping in a controlled situation helps prepare athletes to safely take on the demands of their sport. In sports performance training, this is commonly known as plyometrics, but it’s important for more than just sports performance.
FOR NOW AND FOREVER
If you landed on this to help get past your knee sprain, I hope you found the answers you were looking for. It’s going to take some time, and we would love to help guide you through that.
Our 30-Day Knee Fix will give you a progression of strengthening and active rest to get you back to where you once were.
But it doesn’t end there! Hip and Core strengthening is an important part of knee injury prevention and should be part of every athlete and active person’s regiment. Be sure to check out our glute and core guide to learn more about the key muscles needed to fight off injury.