Knee joint instability is a condition in which your knee is unable to support the weight of your body and feels as though it is “giving way”. The most common cause of this condition is damage to the ligaments that hold the bones of your knee (patella, femur and tibia) together. This type of damage typically occurs during sports activities, particularly ones that involve running, jumping and changing speed and/or direction while running at high speed. If you have knee joint instability, the symptoms will include this “giving way” feeling, as well as a “looseness ” in the knee. To treat mild knee instability, your doctor may recommend resting, icing, compressing and elevating your knee as much as possible. If these measures do not work, you may need to undergo corrective surgery.
Causes Of Knee Joint Instability
As we have mentioned at the start, knee joint instability is most commonly due to ligament damage. This can be a mild sprain, meaning overstretching with microscopic tearing, or it can involve ligament tearing or rupture. In the most severe cases, the ligament may have completely separated from its adjacent bone.
ACL injuries are particularly likely to cause instability. The anterior cruciate ligament (ACL) is one of the most important ligaments of the knee and acts to preserve stability in a front to back (or vice versa) direction.
Collateral ligament injuries can also result in knee joint instability. There are two of these ligaments – one positioned on either side of your knee. They act to preserve knee stability in a sideways directions.
This type of ligament damage is usually a result of trying to change direction while running but having your knees locked in one direction while the rest of your body turns in the direction you want to go. It can also be the result of trying to come to a dead stop from a full out sprint and using a flexed knee joint as a “brake”.
Other Possible Causes
However, sometimes knee instability can have other causes. Less commonly, it can be a result of damage to knee muscles. It can also be a result of fluid accumulation in the knee due to another, unrelated, injury. Knee osteoarthritis can sometimes lead to knee instability as a secondary result.
Other, even less common, factors that can cause knee instability may include the following (please note that this is not an exhaustive list):
A torn meniscus or menisci. The meniscus sits between your patella (kneecap) and tibia (shinbone) and acts as a “shock absorber” between the two bones while you walk or run.;
Congenital factors, i.e. you may have been born with loose joints (double jointed).
The symptoms of knee joint instability can include some or all of the the following:
A feeling that your knee cannot support your full weight, or having your knee buckle under you;
A feeling of “looseness” in your knee;
A “locking” or “catching” sensation in your knee;
Difficulty straightening your knee, or a decrease in the joint range of motion;
Knee pain and/or swelling.
If you believe that you may be experiencing knee joint instability because you have noticed some of the symptoms listed above, you should make an appointment with your doctor for a professional examination. If you try to treat this injury yourself, you may have increased the risk that you can develop a chronic knee injury or that your instability may turn into something more serious. Your doctor is qualified to examine your knee, determine what type of injury you have and how serious it is, and finally recommend a treatment plan.
To make a diagnosis, your doctor will likely physically examine your knee and ask questions about other injuries you may have experienced in the past. He or she may also request an X Ray or MRI scan of your knee to assess the extent of ligament damage (or to see whether there is a bone fracture as well).
Treatment Of Knee Joint Instability
If your knee instability is due to another underlying injury, your doctor will likely try to treat it by addressing that underlying injury. Once the primary cause of the knee instability has been treated, the instability itself should go away.
However, if your knee joint instability is due to ligament damage, treatment will likely involve either:
A conservative home based approach that involves rest for your knee ligaments and allowing them to recover naturally; or
Conservative (Non surgical) Treatment
If your doctor determines that your knee instability is due to minor ligament damage (overstretching and possibly microscopic tears in the ligament) he or she may prescribe one or more of the following:
Resting your knee by refraining from running, jumping or other activities that may stress the ligaments;
Keeping your knee elevated above heart level whenever possible (i.e. when you are sitting or lying down).
If your knee joint instability does not respond to the above conservative approaches, you may be asked to consider surgery. Your doctor may have detected tearing or rupturing of the ligament as part of the initial diagnosis. If so, (s)he may suggest going directly to surgery without trying the conservative approach.
The surgery may attempt to graft ligament tissue from another healthy area of your knee. Alternatively, ligament tissue from a donor may be used to repair your damaged ligaments. To correct the ligament damage using surgery, a tiny camera may be inserted into your knee and used to guide the instruments with which the procedure is performed. This is known as arthroscopic surgery.
Whether your knee joint instability is treated using conservative or surgical methods, your doctor will probably suggest a program of physical rehabilitative exercises. The exercises will use physical therapy to strengthen the muscles of your knee and return it to its normal function. Although this may seen an unnecessary part of your treatment, it is actually an essential step on the path to returning to your original quality of life.