Understanding Fat Pad Impingement

The infrapatellar fat pad is a sensitive mass of tissue that lies behind the patella tendon and on the front side of the knee joint.  With it being located below and behind the distal end of the patella or kneecap, it’s quite vulnerable to trauma and is an obvious source of pain.

It is not the most common of knee injuries but it may be one of the most difficult ailments to eliminate.  The main function of the fat pad, or Hoffa’s pad, is to provide a protective padding to the knee’s condyles located at the distal end of the femur or thighbone.  Many knee injuries involve a blow to the front of the knee and the fat pad is an effective structure to buffer the forces on the vulnerable articular surfaces of the distal femur.

The two most common mechanisms of injury for fat pad impingement is a direct blow to the patella and front of the knee and hyperextension of the knee joint itself.  Both mechanisms create a pinching of the fat pad resulting in swelling of the pad and surrounding tissue.

With this type of a knee injury, the fat pad becomes very painful and slow to heal. Due to the location of the fat pad behind the patella tendon and the high forces associated with the patella itself, an enlargement of the fat pad can significantly impair the overall function of the knee and quickly limit the athlete’s leg strength.

Signs & Symptoms of an Impingement of a Fat Pad

  • Palpable swelling below and to both sides of the patella tendon.
  • Pain below and to the sides of the patella tendon with squatting.
  • Pain below and to the sides of the patella tendon with leg extension along with noticeable bulges to the sides of the patella tendon when the knee reaches full extension.
  • Increased warmth and a sense of fullness in front of the knee below the patella.
  • The inability to actively extend the knee to full extension due to pain when pressure is applied to both sides of the patella tendon.  This is referred to as a Hoffa’s Test.

Professional Treatment for Fat Pad Impingement

  • Resting the knee while avoiding all activities that apply pressure to the anterior knee and/or increase symptoms.
  • Ice, ice and more ice.
  • The necessary modalities and therapy devices to reduce swelling, decrease pain and restore normal knee mechanics.
  • The use of a roller and massage therapy for the hip flexors, quadriceps, ITB, hamstrings and calves to increase tissue mobility and reduce patella compressive forces.
  • Painfree flexibility activities for the hip flexors, quadriceps, ITB, hamstrings and calves to improve lower extremity range of motion.
  • Implement a quad-strengthening program that is painfree while being performed in a range of motion between 90 degrees of flexion and 20 degrees from full extension.
  • Patellofemoral taping can be an effective treatment for sub-acute and chronic knee injuries that involve the patella and the patella tendon.
  • Knee sleeves that provide stability and motion control to the patella may be helpful if additional pressure is not applied to the infrapatella area.

Asking the Questions a Pro Athlete Would Ask

Here’s what a smart pro athlete would ask his/her sports medicine specialists to ensure a fast and safe return to sports:

  1. Are you certain of the diagnosis (Dx) of fat pad impingement and does this Dx match my mechanism of injury (MOI)?
  2. Are there any additional complications to this injury that I need to be made aware of?
  3. I’m concerned about losing my quad strength so what can I do to help me maintain my lower extremity strength?
  4. Do I show any signs of a mechanical abnormality such as a leg length discrepancy or chondromalacia that needs to be addressed in addition to my fat pad injury?
  5. What type of progression do I need to follow when I return to my sport?

Elite Sports Medicine Tips from Mike Ryan

  • Start Treatment ASAP – You don’t want a chronically inflamed fat pad.  Treat it the right way now and be done with it.  If you wait expecting it to “just go away”, you may be sorry that you did.
  • No Go 2 Stop & Go – Stop & go sports such as tennis and basketball are no friend to a painful fat pad.  Don’t be in a rush to return to such sports until the swelling is minimal, the quad strength is at least 90% and the pain is mild.
  • Pray for Help – Kneeling on the knee, as in the praying position, will increase the symptoms of an inflamed fat pad.  I’m not suggesting that you stop praying but a simple pillow under your knee will help make your religious duties much more comfortable.
  • Looking Elsewhere – If your fat pad is painful yet the mechanism of injury just does match up, the problem may be from somewhere else.  Chronic foot pain, tight hips, a symptomatic plica and Jumpers Knee are just a few examples of injuries that can indirectly inflame a fat pad.
  • Avoid the Knife – I have seen very few fat pads that required surgery.  I strongly suggest that you avoid getting surgery on this issue until you have exhausted all of your conservative options and been diligent with your rehabilitation.