What Is Fat Pad Syndrome?
There are many structures capable of causing pain in the front of the knee, one such potential source of anterior knee pain is the fat pad. This “fat pad” in the knee is known specifically as the infrapatella fat pad and is a mass of fatty tissue sitting just below the kneecap. Positioned deep to the patella tendon wedged in this infrapatella space, enclosed between the tiba-femur bones (behind), patella tendon (in front) and the kneecap (above). The fat pad is considered to be a sensitive soft tissue and with that a potential source of knee pain
. Fat pad syndrome is a condition where irritation to the fat pad occurs through pinching of the pad, pinching if a soft tissue like this in the physio world is referred to as impingement
What Are The Potential Causes Of Fat Pad Syndrome?
Fat pad syndrome also referred to as Hoffa’s syndrome occurs when the infrapatella fat pad becomes irritated. Such irritation can have multiple causes ranging from;
- receiving a direct blow to the area (local trauma) from a fall onto the knee, or blunt trauma directly to the area
- a hyperextension injury, as can occur when landing awkwardly from a jump, or in a tackle where the knee is forced backwards on a planted foot
- or the result of chronic irritation
The infrapatella fat pad sits all squished in the space just below the knee cap, therefore variations in kneecap anatomy, or knee biomechanics can potentially alter the risk of developing fat pad impingement. One biomechanical variation reported to increase the risk is genu recurvatum, or naturally occurring hyperextension of the knee. Individuals with a knee that bends backwards excessively in standing may be a higher risk of developing Hoffa’s syndrome because during many normal daily activities the inferior pole of the patella is more likely to “pinch” up against the fat pad compressing it when the knee hyperextends.
Hyperextension Injury And A Pinched Fat Pad
Hyperextension injury as noted above is considered a cause of fat pad syndrome. When the knee is unnaturally forced into a position of extreme extension, such as landing from a jump, or being tackled playing football then this trauma can trigger pinching of the inferior pole of the knee cap forcefully against the fat pad squishing it between the hard boney surfaces of the kneecap and the knee.
Direct Trauma And Fat Pad Pain
A direct blow to the knee can also impact and irritate the fat pad. Some examples of direct trauma include falling forwards onto the front of the knee landing directly on the space in front of the fat pad. A motor vehicle accident whereby the front of the knee is slammed into the dashboard on impact. A tackle playing sport where body part, or implement is driven into the front of the knee via an opponent.
Degenerative Knee Complaints And Fat Pad Syndrome
Degenerative knee complaints
such as osteoarthritis of the knee has been highlighted as another potential cause of developing fat pad pain as is fibrosis (hardening) of the fat pad. Tight quadriceps although not a degenerative complaint is something that can occur over time or be genetically predisposed has also been suggested as a potential cause through tightness of these muscles potentially creating increased tension on the kneecap and patella tendon.
Could I Have Hoffa’s Syndrome
With Hoffa’s syndrome knee pain may be aggravated by a number of activities including jumping, prolonged standing, or any position that causes the knee to hyperextend. Unlike patella tendinopathy which is another condition that can cause pain to occur in a similar location, with fat pad impingement the pain isn’t confined to the proximal tendon. And as a rule pain originating from the patella tendon has a tendency to be a more localised pain than that of a symptomatic fat pad.
Common signs and symptoms of fat pad syndrome include:
- Pain is typically felt in the front of the knee just below the level of the knee cap.
- Swelling may or may not be present, if there is swelling again this is likely to be noted locally just below the level of the knee cap.
- Pain is commonly experienced when straightening the knee towards full extension and in positions of hyperextension.Typically simple everyday aggravating positions and activities that encourage hyperextension of the knee may include: resting your leg out straight when putting your feet up on the coffee table, standing still for a prolonged time, walking (or standing) in high heels.
- In athletic adventures someone suffering from fat pad related pain will likely experience pain with jumping and kicking actions which can both rapidly push the knee into hyperextension triggering sharp pain.
The Diagnostic Process With Hoffa’s Syndrome
Symptoms associated with Hoffa’s syndrome are similar to that of a number of other knee conditions and fat pad syndrome can coexist with other knee pathology’s so obtaining an accurate diagnosis regarding the source of discomfort or functional limitation assists in appropriate advice and rehabilitation to be prescribed. Via a subjective understanding regarding the history and behavior of symptoms and physical assessment of the knee your physiotherapist can develop an understanding of the complaint. Frequently clinical assessment by your physiotherapist is satisfactory for “landing on” a diagnosis of fat pad irritation being the relevant source of knee pain. However, the use of investigations such as MRI, or ultrasound imaging may sometimes be used to aid diagnosis and treatment planning.
Physio Treatment And Fat Pad Syndrome
Physiotherapy guided rehabilitation will hasten recovery and a frequent starting point is the modification of load and aggravating activities. Some treatment modalities used by our physiotherapists at The Movement Centre may include:
- Soft tissue release and stretching techniques/exercises in an attempt to restore soft tissue range of motion often in an attempt to reduce the forces that tight quadriceps may create at the knee/kneecap.
- In an attempt to manage discomfort the application of cryotherapy, electrotherapy, dry needling… may be offered.
- Taping, in an attempt to offload, assist patella tracking, improve biomechanics, reduce impingement may also be considered.
- Exercises to improve strength, postural control and biomechanics around the trunk and lower limb are often prescribed.
- Dynamic balance training to improving proprioception, landing technique and functional movement patterns when running, jumping, hopping, squatting… can potentially help in offloading painful areas.
- The use of anti-inflammatory agents may be used in some situations, such as the application of topical creams such as Voltaren Emulgel, or suggestion of taking oral anti-inflammatory medication which can be obtained from a pharmacy, or prescribed by your GP.
Physiotherapy treatment modalities will look to reduce impingement through improving biomechanics and optimising patellofemoral alignment coupled with reducing irritation, promoting “healing” with therapeutic approaches some of which are listed above.
Preventing Fat Pad Syndrome
Preventing fat pad syndrome in the average Joe could be pretty successful through simply avoiding a few simple activities and postures such as; excessive kneeling, judicious use of high heels, locking out the knees when standing for extended periods, resting your heels up on the coffee table in the evening and kicking a football. If all this fails, then your physiotherapist can help you understand some of your potential risk factors and what you can do to mange this.
Surgery And Hoffa’s Syndrome
Ideally fat pad impingement can be settled conservatively however, if conservative measures fail to achieve satisfactory results and the knee pain symptoms persist then the use of a local corticosteroid injection in an attempt to reduce inflammation and even surgery may be considered. At the Movement Centre we like to think that ideally our physiotherapists could work with you to achieve a satisfactory result, without having to resort to any of these more invasive options.