Hoffa syndrome is a condition due to irritation of infrapatellar fat pad and a cause of anterior knee pain. It is also called Hoffa’s disease or fat pad impingement syndrome or simply fat pad syndrome.
Hoff’s fat pad or the infrapatellar fat pad is a cylindrical piece of fat that is situated under and behind the patella bone within the knee. It is very rich in nerve supply.
It is also called patellar tendon lateral condyle friction syndrome.
Pathophysiology of Hoffa Syndrome
Hoffa syndrome can result from acute trauma or chronic injury. The fat pad can get irritated due to direct trauma to the anterior aspect of the knee or during the course of time.
Chronic irritation is said to occur when on the extension, the inferior pole of the patella tilts back upon the underlying fat pad.
Mostly, this occurs because of hyperextension of the knee. Sports that require frequent kicking or jumping, such as football or volleyball may increase the risk.
Anterior pelvic tilt seen commonly in women wearing high heel shoes pushes the knee into hyperextension which leads to shortening of quadriceps [rectus femoris].
Tightened quadriceps pulls the patella superiorly, tilting the inferior pole posteriorly and causing impingement.
Sports or profession requiring prolonged kneeling are also at risk.
Recurrent episodes of irritation will result in swelling and inflammation of the fat pad and swelling further enhances the impingement, thus setting the vicious cycle.
Patients with Hoffa syndrome would present with acute or chronic sharp pain below the patella which is worsened by activities like walking, prolonged standing, wearing high heel shoes or any other activity that puts their knee into full extension.
On examination, there may be swelling in the infrapatellar region, and it is tender to touch.
The patients get significant relief when the inferior pole of the patella is tipped up and away from the fat pad by pushing the superior border of the patella posteriorly. This posterior pressure, by see-saw effect, lifts the inferior pole of the patella, offloading the fat pad from direct pressure from the patella. This leads to a reduction of the symptoms.
Hoffa’s test is a useful diagnostic test which involves palpating the infrapatellar region for pain. The patient lies supine with knees bent and the examiner presses both thumbs along either side of the patellar tendon in the infrapatellar region. The patient is then asked to straighten their leg. Pain and/or apprehension of the patient is considered a positive sign for fat pad impingement
Treatment of Hoffa Syndrome
Treatment of this condition is normally by conservative methods such as:
- Rest and avoiding aggravating activities.
- Ice therapy to reduce acute pain and inflammation.
- Ultrasound and TENS.
- Taping the patella
- Muscle stretch and strengthening exercises
In the acute period, the aim is to reduce inflammation and pain. Ice can be applied to the infrapatellar region for approximately 15-20 minutes, 2-3 times a day.
Whenever needed NSAIDs can be used to reduce inflammation and pain. Reduction of swelling itself contributes to the reduction of impingement.
Ultrasound and TENS can also help to reduce inflammation and swelling
Taping aims at involves lifting up the inferior pole to offload the fat pad and prevent impingement. The medial and lateral border of the patella is pulled diagonally upwards to sling the patella superiorly and the superior border is be taped across horizontally to tilt the inferior pole away from the fat pad. Range of motion of knee may be restricted.
Taping may also be done to prevent excessive hyperextension which aids in the reduction of the symptoms.
Stretching and Strengthening exercises of quadriceps and hamstring muscles are done for gaining a range of motion and strength of the muscle.
The biomechanical factors also need to be addressed Patients are advised to avoid heels and excessive hyperextension of the knee.