Patellar instability describes a range of conditions where the kneecap is displaced from its normal position. It can result from sports or other injuries or develop over time due to daily activities. Patellar instability affects about 7 out of 100,000 people in the United States. People in their teens and 20s are most likely to be diagnosed with some form of the condition. It is most common in teen female athletes.
Symptoms can include pain, swelling, and problems walking or using the stairs. A person may notice a feeling that the kneecap could become displaced. Once a person has had an episode of patellar instability, there is an increased risk for a recurrence.
Physical therapists prescribe specific exercises for those experiencing patellar instability to help decrease pain, restore proper movement, increase strength, and improve function.
Physical therapists are movement experts who improve quality of life through hands-on care, patient education, and prescribed movement. You can contact a physical therapist directly for an evaluation. To find a physical therapist in your area, visit Find a PT.
Normally, the kneecap (patella) rests in a groove on top of the thigh bone (femur). As the knee bends and straightens, the kneecap stays in this groove as it slides up and down. Think of the groove as a train track and the kneecap as the train. Patellar instability describes a situation when the “train,” or the kneecap, “comes off of the track.” It can occur during movement (if the kneecap does not stay in the groove). It also can occur without movement (if the kneecap does not rest properly in the groove).
Patellar instability can result from an injury, or develop over time with daily activities.
With traumatic injury. A specific injury can force the kneecap fully out of its groove, such as a:
The more extreme form of this injury is called patellar dislocation. It occurs equally in males and females. After a dislocation, knee pain will limit your activity. Most often, the kneecap can return to its proper place on its own. Sometimes, however, the kneecap does not relocate on its own. If it does not, you may require a medical procedure called a reduction.
Without a traumatic injury. Patellar instability also can occur without a specific injury. In these cases, the kneecap comes part of the way out of the groove. This occurs most often in females. The kneecap is unstable and does not fully stay in the groove during everyday activities. The knee becomes more irritated and painful with repeated activity. Pain is most common when:
When combined, several factors can lead to patellar instability over time. Some of these can be addressed, and some cannot. They include:
Patellar instability causes pain and other symptoms. These can limit your ability to do daily and leisure activities.
You may experience:
Your physical therapist will review your medical history. They will then complete a full exam of your knee. They also will examine other areas, such as the hip and foot, that might contribute to your condition. Their goal is to assess the degree of your injury and determine its cause(s) and contributing factors. This will help to determine your treatment program.
Your initial exam can include several tests. Your physical therapist may:
X-rays or MRIs are rarely needed to diagnose patellar instability. However, they may help to assess bone alignment and rule out other problems after a traumatic injury or repeated episodes of patellar instability
You and your physical therapist will work together to develop a plan to achieve your specific goals. Based on your exam, your physical therapist will select treatment strategies and design a personalized program for your condition. Your physical therapy treatment program may include some or all of the following:
Pain management. Your physical therapist may use several pain-relief strategies. The most common one is to apply ice to the area. Often, they will provide or recommend a knee brace to hold the kneecap safely in position. Your physical therapist also may recommend that you avoid certain activities for a period of time.
Range of motion exercises. Knee motion is often limited after an injury. Your physical therapist will guide you through targeted exercises to help restore range of motion without worsening your condition.
Muscle strengthening. Improving and balancing the strength in your leg can help control kneecap stability and reduce your risk for reinjury. Your physical therapist will select safe resistance exercises for you. You may begin by doing exercises lying on a table. You then may advance to doing exercises while standing. Your physical therapist will choose the right exercises for you based on your age, physical condition, and goals.
Functional training. Once your pain eases and your strength improves, you will need to safely transition into more demanding activities. The way you move can affect the stability of your kneecap. Your physical therapist will help you build your kneecap stability and lessen your chances of reinjury. They will teach you safe, controlled movements. Your physical therapist is an expert who can design a series of activities to help you move your body correctly.
Patient education. Your physical therapist will work with you to identify and change any external factors causing your pain. This can include the type and amount of exercise you do, and your footwear. They will look at all possible personal factors and recommend improvements. They will develop a specific exercise program designed to help you return to your desired activities pain-free.
Physical therapy promotes recovery by addressing factors that you can modify. These include lack of strength, flexibility, and body control. Your physical therapist also may recommend a rest period during which you avoid activities that aggravate your knee. Afterward, they will help you gradually resume safe activities. At the right time, they will carefully guide your progression into more demanding activities.
If patellar instability remains untreated, pain will persist and may worsen, resulting in long-term difficulty.
Surgery may be needed for a serious tear of the medial patellofemoral ligament. A tear is most common after a traumatic injury or repeated episodes of kneecap instability. Surgery also may be recommended if your condition does not improve after several weeks of physical therapy.
The goal of surgery is to restore normal kneecap stability. Depending on your specific condition, your surgeon may:
After surgery, you will receive physical therapy to:
Immediately after surgery, you may be required to limit any movement of the knee to help it heal. At the right time, your physical therapist will help guide you through exercises to safely increase your knee motion. They also will address any factors that caused your knee injury, to minimize the risk of reinjury.
Your physical therapist will then help you reintroduce more challenging movements while avoiding overstraining your knee. They will help you gradually add activities such as:
They will guide you through safely adding activities into your routine without overstraining your knee.
Caution: Keep in mind that returning to activities too soon after injury often leads to lasting pain. It also can make it harder to resolve the condition. Your physical therapist will monitor your progress and recommend only those movements and activities that can safely lead to recovery.
Not all cases of patellar instability can be prevented. However, the best ways to prevent the condition are to:
Physical therapists understand which movements put you at highest risk for patellar instability. One of the goals of physical therapy is to educate you on proper movement techniques to keep your knee safe. They will assess how you move, and then provide the right exercises to allow you to move safely.
For athletes, this may include observing and improving the way you jump, land, pivot, and cut. For others, it may include improving the way you climb stairs or even how you sit in a chair. Your physical therapist will identify which movements to improve to minimize your risk of knee injury.
Experiencing patellar instability once increases the likelihood of reinjury in the future. To reduce this risk, a physical therapist will select exercises specific to you. Exercises to increase your strength will, in turn, help increase your stability. You also may work on improving your control when doing activities like running, cutting, and jumping. Your physical therapist can safely guide your return to activity, introducing tasks at the right time for you. They also may recommend using a brace when doing higher-level activities to reduce your risk of reinjury.
Physical therapy can reduce your risk of reinjury and help you return to your regular activities.
All physical therapists are prepared through education and experience to treat various conditions, such as patellar instability. You may want to consider:
You can search for physical therapists in your area who have these and other credentials by using Find a PT, a tool built by the American Physical Therapy Association.
General tips when you’re looking for a physical therapist (or any other health care provider):
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