Patellar Instability Specialist

Urgently Ortho

Orthopaedic Urgent Care, Sports Medicine & Wellness Clinics located in Scottsdale, AZ

Patellar Instability Q&A




Three bones meet to form your knee joint: your thighbone (femur), shinbone (tibia), and kneecap (patella). The patella lies in front of your knee and assists in bending of your knee.  There is a tendon that attaches to the top and bottom of the patella, this tendon allows the function of the big four muscles in the front of your thigh (quadriceps) to happen.   The patella sits in a groove on your femur. This groove may not be very deep or the angle from your hip to your ankle may cause the patella to slide out of the groove.  When the patella slides out of the groove, we call that patellar instability. It almost always slides to the outside (lateral)



Patellar Instability can happen due to several issues:

  • Bone structure: Shallow groove where the patella slides up and down.  It does not provide a stable base on which the kneecap can rest.  Wider hips or “knock knees” can contribute to patellar instability.
  • Muscle weakness: The muscles surrounding the hip and knee need to be strong to help control the position of the leg and keep the kneecap stable.
  • Soft tissue malfunction: Ligaments and tendons also work to hold the kneecap in place. These tissues may be very loose since birth, or those who have previously experienced an episode of patellar instability, these tissues may have stretched out, losing their ability to hold the kneecap properly in place. In other cases, the soft tissue on the outside of the knee is too tight and pulls the kneecap out of its ideal resting place in the groove.
  • Poor movement patterns: Activities, such as running, jumping, and landing with the knee in a bad position makes the kneecap vulnerable for patellar instability.




Following the injury, you may feel a "pop" or be unable to bend your knee.  The knee may not look “right”, as the patella is not sitting in the correct location.  The most common symptoms of patella instability are:

  • Pain with straightening of the knee
  • Stiffness and swelling
  • Visible movement of the patella (most often

to the outside of the knee)

  • Tenderness around your patella
  • The sensation of your knee "giving way"
  • You are not able to move your knee through

its full range of motion



Physical Examination

During your first visit, be prepared to explain how you hurt your knee and how it feels since the injury.  The more you can explain to your provider, the more they can understand your symptoms and medical history.

At your visit, your provider will perform a physical exam and evaluate all the structures of your knee.  You will receive an x ray to determine if there are any fractures present.  X ray can assist with evaluating the bone structures and assist with determining the cause of the patellar instability.

Many Patella Instability injuries can be diagnosed with a thorough physical examination of the knee, but other tests, such as a Magnetic Resonance Imaging (MRI) scan may be ordered. The MRI creates better images of soft tissues like the ligaments and tendons.  These images allow the physician to determine if this injury requires non-surgical or surgical treatment



Treatment for Patella Instability is most often Non-Surgical first.  After exhaustive non-surgical treatment, surgery may be needed to correct the problem.

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.


Non-Surgical Treatment

Initially, the standard treatment is the RICE protocol.  This stands for:

  • Rest. Take a break from the activity that caused the injury. You may need to use crutches to avoid putting weight on your leg.
  • Ice. Use cold packs for 20 - 30 minutes at a time, several times a day.
  • Compression. To prevent additional swelling apply an elastic compression bandage.
  • Elevation. Lift your leg up higher than your heart.

In addition to the RICE protocol, there are many types of non-surgical treatment options for Patellar Instability and all have their advantages and disadvantages.  Your Orthopedic Specialist can review these options and assist you in determining which will be most effective in treating your injury:

  • Non-steroidal anti-inflammatory medicines
  • Physical Therapy
  • Bracing
  • Taping
  • Orthotics
  • PRP (Plasma Rich Protein) injections
  • Stem Cell Therapy


Surgical Treatment

If the symptoms persist after exhaustive non-surgical treatment, you may need surgical treatment to correct the Patellar Instability.  There are many possible procedures to correct this issue, the best option is dependent upon the cause to the patella instability.  The Orthopedic Surgeon may tighten ligaments, or they may correct bone abnormalities.  All the options will be discussed if non-surgical treatment does not rectify the Patellar Instability. 



The first line of treatment is always rehabilitation.  A physical therapy program will guide you in regaining knee function strength and function.  This may occur in conjunction with bracing or taping.  Your rehabilitation specialist will assist in the decision-making process for the best options.