Patellar instability is the term given to a range of injuries that occur when the patella, or kneecap, is displaced from its intended resting place.
Causes of patellar instabilities include
The condition affects an average of 7 out of 100,000 individuals in the United States, and is most often diagnosed in individuals in their teens and twenties, particularly adolescent female athletes.
Once individuals have experienced an episode of patellar instability, they are at an increased risk of another episode, with 15% to 44% experiencing it again.
To treat patellar instability, our senior physiotherapists typically
prescribe a combination of strengthening exercises to decrease pain and
Under normal circumstances, the kneecap (patella) properly rests in a groove (trochlea) at the end of the thigh bone (femur).
As our knee bends and straightens, the kneecap should slide up and down, staying in this groove. This function is often illustrated with 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."
This can occur during movement as the kneecap does not stay in the groove, and/or without movement if the kneecap does not rest properly in the groove.
Patellar instability can be either the result of a specific injury, or may slowly develop over time with daily activities.
An event, such as a direct hit to the knee or changing directions quickly while running (eg, "cutting" during sports activities), can force the kneecap fully out of the groove (patellar dislocation). This is called a traumatic injury and occurs with equal frequency in males and females.
Patellar instability can also be present without a specific injury when the kneecap comes partially out of the groove (subluxation).
This is called an atraumatic (non-traumatic) injury and occurs most often in females. In this situation, the kneecap does not rest and/or stay appropriately in the groove with daily activities.
While the kneecap may not come completely out of the groove, the unstable kneecap will still cause knee pain—most commonly while the patient is
As these activities are repeated, the knee becomes increasingly irritated and painful.
Patellar instability also may result from a combination of several different variables, both modifiable and nonmodifiable, including abnormalities in:
Individuals with patellar instability will experience pain and other symptoms that can limit their ability to perform desired daily and recreational activities.
With patellar instability, you may experience:
Our senior physiotherapists will review your medical history and complete a thorough examination of your knee, while also examining other body parts that might contribute to your injured area, most commonly the hip and foot.
The goals of the initial examination are to assess the degree of the injury and determine its cause and contributing factors to the injury.
We will also gently touch the front, side, and back of your knee to determine exactly where it is most painful.
We may also ask questions regarding your daily activities, exercise regimens, and footwear, to identify other contributing factors to your pain.
Imaging techniques, such as X-ray or MRI, are typically not needed to diagnose patellar instability, but may be valuable following traumatic injuries or repeated episodes of instability, in order to evaluate your bone alignment and rule out other knee pains and injuries.
You and our senior physiotherapists will work together to develop a plan to help achieve your specific goals. To do so, we will select treatment strategies in any or all of the following areas:
Many pain-relief strategies may be implemented.
The most common one is to apply cold therapy to the area. A knee brace is often provided to hold the kneecap in a stable position. Avoiding certain aggravating activities for a period of time might also be recommended.
Range of motion
Your knee motion is often limited after an injury. We will work with you to select exercises that will help regain your motion without hurting your knee.
Improving and balancing the muscle strength in your leg can help control the stability of your kneecap. Based on your specific condition, we will design a safe, individualized, progressive program of resistance exercises for you.
You may begin by performing strengthening exercises lying on a table, for example, lifting your leg up while lying in different positions. You then may advance to exercises in a standing position, for example, stepping onto a box or balancing on 1 leg.
We will choose what exercises are right for you, based on your age, physical condition, and goals.
Once your pain eases and your strength improves, you will need to safely transition back into more demanding activities. The way you move while performing these activities can significantly affect the stability of your kneecap.
To maximize its stability and minimize your risk of repeated injury, it is important to teach your body safe, controlled movements. Based on your own unique movement assessment and goals, we will create a series of activities to help you learn how to use and move your body correctly and safely.
We will work with you to identify and change any external factors causing your pain, such as the type and amount of exercise you do, and your footwear.
We will assess all possible factors and recommend improvements, and develop a personal exercise program to help ensure a pain-free return to your desired activities.
Physical therapy promotes recovery from patellar instability by identifying and addressing all modifiable contributing factors, such as any lack of
We may also recommend a period of relative rest during which aggravating activities are avoided, then help you slowly resume safe activities, and carefully guide your progression.
When patellar instability remains untreated, however, your pain will persist and may worsen, resulting in long-term difficulty performing your desired activities.
In the event of a serious ligament tear (of the medial patellofemoral ligament), caused by either a traumatic injury or repeated episodes of the kneecap coming out of its groove, or cases that do not improve following several weeks of knee physiotherapy, corrective knee surgery may be required.
The goal of surgery is to restore normal kneecap stability. Depending on the condition, the surgeon may use new tissue to reconstruct a damaged ligament, release tight surrounding soft tissue that is pulling the knee off track, or make changes to the bone alignment of the thigh and/or shin bone.
Following surgery, your initial rehabilitation will focused on
Immediately after surgery, movement of the knee may be limited to help it heal. As time passes, our senior physiotherapists will help guide you through exercises to safely increase your knee motion.
We will also address specific factors that caused your knee injury, in order to minimize the risk of further injury. As you progress, we will help you systematically reintroduce activities, such as stair climbing, squatting, and desired recreational activities.