Unstable Kneecap
As long as your kneecap (patella) stays in its groove in the knee, you can walk, run, sit, stand, and move easily. When the kneecap slips out of the groove, problems and pain often result.
Cause
The kneecap connects the muscles in the front of the thigh to the shinbone (tibia). As you bend or straighten your leg, the kneecap is pulled up or down.
The thighbone (femur) has a V-shaped notch (femoral groove) at one end to accommodate the moving kneecap. In a normal knee, the kneecap fits nicely in the groove. But if the groove is uneven or too shallow, the kneecap could slide off, resulting in a partial or complete dislocation.
A sharp blow to the kneecap, as in a fall, could also pop the kneecap out of place.
Symptoms
- Knee buckles and can no longer support your weight
- Kneecap slips off to the side
- Knee catches during movement
- Pain in the front of the knee that increases with activity
- Pain when sitting
- Stiffness
- Creaking or cracking sounds during movement
- Swelling
Diagnosis
Physical Examination & Patient History
During your first visit, your doctor will talk to you about your symptoms and medical history. During the physical examination, your doctor will check all the structures of your injury, and compare them to your non-injured anatomy. Most injuries can be diagnosed with a thorough physical examination.
Imaging Tests
Imaging Tests Other tests which may help your doctor confirm your diagnosis include:
X-rays. Although they will not show any injury, x-rays can show whether the injury is associated with a broken bone.
Magnetic resonance imaging (MRI) scan. If your injury requires an MRI, this study is utilized to create a better image of soft tissues injuries. However, an MRI may not be required for your particular injury circumstance and will be ordered based on a thorough examination by your Peninsula Bone & Joint Clinic Orthopedic physician.
Treatment Options
Non-Surgical
If the kneecap has been completely dislocated out of its groove, the first step is to return the kneecap to its proper place. This process is called reduction.
Sometimes, reduction happens spontaneously. Other times, your doctor will have to apply gentle force to push the kneecap back in place.
A dislocation often damages the underside of the kneecap and the end of the thighbone, which can lead to additional pain and damage to the cartilage on either the undersurface of the kneecap or covering the thighbone. Occasionally, a loose piece of cartilage is created. Arthroscopic surgery can correct this condition.
If the kneecap is only partially dislocated, your doctor may recommend nonsurgical treatments, such as exercises and braces.
Exercises will help strengthen the muscles in your thigh so that the kneecap stays aligned.
Cycling is often recommended as part of the physical therapy. A stabilizing brace may also be prescribed.
The goal is for you to return to your normal activities within 1 to 3 months.
Surgical
A chronic condition, in which the knee continues to be unstable, can often be corrected by surgery. For example, surgery can be used to realign and tighten tendons to keep the kneecap on track, or to release tissues that pull the kneecap off track.
