Patella Fractures

The patella, or knee cap, is a small bone that protects the front of the knee. Patella fractures occur when this bone breaks due to a forceful impact. Patella fractures are serious injuries that require medical attention, as they can hinder your ability walk due to pain and mobility deficits.  

Kneecap Anatomy

The patella is a small bone that is attached to the patellar tendon, which connects the thigh muscle (quad) to the shin (tibia). The back of the patella consists of articular cartilage, which helps with smooth articulation with the bottom of the femur (thigh bone) when the knee bends and extends during activity.

anatomical image on kneecap or patella and knee anatomy with labels

How Do You Fracture the Patella?

The patella is most commonly injured from a forceful, direct impact. This injury may occur from any of the following:

  • Falling onto knee (particularly from a height)
  • Car accident – knee hits into dashboard
  • Athletic Injury – hard direct blow from athletic equipment (stick, ball, etc.)
  • Forceful contraction of quadriceps muscle

Signs and Symptoms of a Patella Fracture

  • Pain in the front of knee
  • Swelling
  • Bruising
  • Inability to weight-bear (stand/walk)
  • Difficulty bending or straightening knee
  • Unable to perform straight leg raise
  • Deformity

Types of Patella Fractures

The patella can fracture in many ways depending on the mechanism of injury. Direct force applied to this bone can cause various degrees of fracture ranging from hairline cracks to complex fractures.

  • Stable (Non Displaced fracture) – patella bone fragments remain aligned.
  • Displaced fracture – patella fragments have separated and shifted out of position, discontinuity of bony alignment.
  • Comminuted fracture – patella has shattered into 3 or more fragments (may be stable or unstable)
  • Non-comminuted (Transverse) fracture – patella has broken into 2 fragments.
  • Hairline fracture – also known as “stress” fractures, small fracture where patella remains intact. Uncommon in the patella, but may occur in endurance athletes after repetitive force.

Patella fractures should not be confused with patellar tendonitis symptoms.

Open vs Closed Patella Fractures

  • Closed Fractures – broken patella pieces stay enclosed, do not break the skin.
  • Open Fractures – patella fragments have pierced the skin, requiring medical intervention to align pieces of bone and avoid infection.

Diagnosis of a Patella Fracture

If you have recently injured your knee and suspect a possible patellar fracture, it is important to seek medical attention for further evaluation and treatment. In order to diagnose a patellar fracture, your physician will likely do the following:

  • Patient History – specifics regarding how the injury occurred.
  • Physical Examination – MD will evaluate injured knee (checking bony alignment and range of motion). Your physician will check for a condition called hemarthrosis, where blood from the fractured patella accumulates in the joint causing pain. This condition may require blood to be drained prior to x-ray to alleviate pain and provide clearer diagnostic imaging.
  • Diagnostic Imaging: X-rays will be taken to confirm diagnosis. Additional imaging to assess soft tissue structures may be required (MRI, CT scan).

JOI Patella or Patellar FracturePatella Fracture

Non-Surgical Treatment of Patella Fractures

Used for stable patellar fractures:

  • Casting or bracing (in extension)
  • Non-weightbearing with use of assistive device (crutches), often 6-8 weeks.
  • Pain Medication
  • Physical Therapy (after acute healing phase)

Surgery for Patella Fracture

Used for displaced fractures, open fractures often scheduled immediately due to risk of infection.

  • Hardware utilized to stabilize segmented patella pieces.
  • Repair damaged soft tissue associated with injury.
  • Immobilization (bracing in extension)
  • Prolonged non-weightbearing, often 6-8 weeks.
  • Pain Medication
  • Physical Therapy (after acute healing phase)

Recovery from a Patella Fracture

Physical therapy plays an important role in recovery following patellar fracture. Your physical therapist can help to restore knee mobility and quad strength that is lost during immobilization. Depending upon severity of injury, recovery may take anywhere from 3-6 months.  

Related Links:

If you have knee pain or are concerned about a possible patella fracture, the Jacksonville Orthopaedic Institute can help. To see a JOI Orthopedic specialist, call (904)JOI-2000, schedule online, or click the link below. To see a JOI Rehab Therapist in 1 of our 12 locations, call (904)858-7045.

By: Lisa Chekanowsky, LAT, ATC

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