Knee joint instability refers to the medical condition under which the tissues of the knee (muscles, ligaments or bones) weaken to the point at which the bones are not held in their proper place. In most cases, this instability results from a knee ligament injury as these ligaments are normally responsible for holding the joint together. Individuals suffering from knee instability will feel as though the knee is unable to support their full body weight and is “giving way” beneath them. Knee joint instability is usually treatable at home using rest, icing, compression and elevation of the knee. If the instability is serious (probably due to a ruptured or detached ligament) surgery may be necessary to correct the problem.
Knee joint instability due to ligament damage can be a result of either injury or overuse. In other (less common) cases it can be a result of a congenital condition known as being “double jointed”. Double jointed individuals are born with knee joints that are looser than normal.
Other potential causes of knee joint instability include primary injuries that then cause instability as a secondary condition. These primary conditions can include injuries such as knee osteoarthritis and patellar instability, among others.
Individuals whose jobs or other activities require extensive use of their knee are more liable to suffer from instability. These include athletes, especially those in sports requiring plenty of running, jumping and sharp changes in speed or direction while running. Sports like football, soccer and rugby fall into this category. Other activities that make strenuous demands of the knees include gymnastics, dancing and even skiing.
As we have mentioned earlier, those with knee joint instability will have difficulty supporting the normal body weight on an unstable knee. There will be a feeling that the knee is “giving way” beneath them.
One way to test for instability at home is to try to stand on one leg (the one with the suspect knee). If the knee cannot support the weight in this position, knee joint instability may be a factor. The next step should be to schedule an appointment with a doctor for an examination and diagnosis.
To confirm a suspected case of instability, doctors will perform various physical tests. The goal will usually be to check the movement of the knee and to listen for unusual sounds while doing so. As mentioned earlier, some cases of knee instability are due to other primary causes. If this is the case, the aim would be to treat those primary causes so that, once they have been corrected, the knee joint instability should resolve itself.
Other steps that doctors may take during the examination & diagnosis stage include:
Asking the patient about previous injuries, especially any (s)he may have suffered just before the appearance of the instability;
Perform X-Ray or MRI scans of the knee to see whether there is bone damage and to assess the extent of ligament or cartilage damage.
Treatment Of Knee Joint Instability
As we have mentioned above, some cases of instability have another, underlying condition such as knee osteoarthritis as the primary underlying cause. In these cases, the focus will be on treating the primary cause rather than the instability.
If the knee joint instability does not have another injury as its cause, most doctors will, as a first step, attempt to treat it at home using conservative (non surgical) methods. These will usually include some or all of the following:
Resting the knee by abstaining from strenuous activity like running or jumping that could stress the knee ligaments and aggravate the instability;
As part of resting the knee, having the patient wear a hinged knee brace or knee stabilizer that provides lateral support and takes pressure off the LCL and MCL knee ligaments. A hinged brace will also help to prevent knee hyperextension and that will in turn take pressure off the ACL ligament;
Another way of providing additional knee support is by applying athletic tape to the joint. A therapist can do this in such a way as to provide lateral support that will help to protect injured LCL or MCL ligaments;
Icing the knee or applying a cold compress. This may be done for periods of 20-30 minutes, and at intervals of 2-3 hours, for best results;
Elevating the knee above heart level whenever possible. This will optimize blood circulation through the knee and aid in ligament healing.
Once the ligaments are well on the way to healing, the patient should start to work with a physiotherapist on rehabilitative exercises that will strengthen the knee muscles and ligaments. This will help to reduce the risk of recurrence of the knee joint instability.
If the knee joint instability is a result of severe ligament damage such as rupturing, the conservative treatment approach may not be enough. A surgeon can perform arthroscopic knee surgery to repair the ligament and, if necessary, reattach it to the adjacent bone.
To do this, the surgeon may either take a portion of healthy ligament tissue from another part of the knee. Alternatively, (s)he may use ligament tissue donated by another individual.
Once surgery is complete and healing is underway, rehabilitative exercises may be required to ensure the knee returns to full health with less or no risk of recurrence of instability.