Fat pad impingement occurs if the infrapatellar fat pad or Hoffa’s pad is impinged due to direct trauma to the kneecap. The fat pad is crushed between the femoral condyle and the patella. In cases where strong forces strike the patella, it functions as a shock absorber to protect the underlying structures.
Since the fat pad is a highly sensitive structure in the knee, the injury can be quite painful. The condition is usually long-standing since it is aggravated by flexing or straightening of the knee joint. Understandably, the fat pad is under continuous irritation and might become inflamed significantly.
What are the indications?
The indications of fat pad impingement include the following:
- Soreness around the base and beneath the patella
- The individual might have a history of being able to straighten the knee or hyperextension
- The base of the patella might tilt due to the swelling below
The individual might have a history of being able to straighten the knee or hyperextension.
If the condition is suspected, the therapist might perform the Hoffa’s test to confirm a diagnosis.
What is the Hoffa’s test?
During this test, the individual is placed in a lying position with the knee flexed. The doctor places pressure using both thumbs along whichever side of the patellar tendon which is right beneath the patella.
The individual is instructed to straighten the leg. When a diagnosis of fat pad impingement is confirmed, there is pain and/or uneasiness of the individual.
Management
The treatment for fat pad impingement includes conservative measures rather than surgery. The individual should take a break and avoid engaging in activities that can worsen the symptoms.
Apply an ice pack to minimize the pain and inflammation. The ice pack should be applied for 10 minutes every hour initially as the symptoms settle. Make sure that a barrier is placed over the affected area before the pack is applied.
Electrotherapy such as TENS or ultrasound might also be used. Strengthening of the muscles is also recommended to maintain fitness and strength of the adjacent muscle groups if the pain allows.
Taping of the patella is also effective in treating fat pad impingement. In one method, it involves taping of the upper surface of the patella to provide more space for the structures below the lower surfaces. In case conservative measures fail, surgery might be an option. This usually involves full or partial removal of the fat pad.