[Infrapatellar Fat Pad Syndrome] [Transarterial Microembolization (TAME)] Success Story Sharing

Author: Bow Wang, M.D.

Ms. K, 32 years old, injured her left knee in a car accident two years ago. Since then, she has suffered from persistent pain in the lower front of her knee, scoring 9 out of 10 in pain, along with swelling and intense tingling upon touch. Physical examinations and imaging revealed no fractures, ligament damage, tendon damage, or meniscus damage. She was diagnosed with post-traumatic sympathetic dystrophy and infrapatellar fat pad syndrome.

Ms. K has undergone rest, rehabilitation, medication, and even arthroscopic surgery, but her pain has not significantly improved.

Finally, after consulting with Dr. Zhang Zhiwei, Chief Physician of Orthopedics at National Cheng Kung University Hospital, she was referred to the outpatient clinic of Bow Wang, M.D. Interventional Medical Center for further discussion.

After discussing with Ms. K, Bow Wang, M.D. performed transarterial patellar embolization. Guided by X-ray fluoroscopy and under local anesthesia, a microcatheter was inserted through the femoral artery in the groin area. Under arterial angiography, contrast agent was injected to locate newly formed capillary-like vessels in the infrapatellar fat pad of the anterior knee. Embolizing medication was then injected through the microcatheter to remove these abnormal capillary-like vessels (see the two images below).

Ms. K's knee pain improved significantly on the day of treatment. Two months later, her pain score dropped from 9 to 2, and the swelling and tingling sensations gradually improved and disappeared (see video below).

This video was recorded and uploaded with the patient's consent.

There are many causes of anterior knee pain, and infrapatellar fat pad syndrome is one of them. This syndrome is also known as Hoffa's disease.

This diagnosis was proposed by scholar Hoffa in 1903. It generally refers to the infrapatellar fat, which becomes inflamed and swollen due to repetitive strain or trauma. The main symptoms include pain in the front of the knee, increased pain with extension, swelling, and joint effusion.

This condition can occur at all ages and in both sexes. Causes include acute injury or chronic repetitive pressure. Repetitive friction or impact leads to inflammation of the fatty tissue between the patella and femur.

Generally, besides trauma, those who frequently climb stairs and engage in sports that repetitively use their knees are more susceptible to this condition. Risk factors include frequent sudden bending or straightening of the knee joint, such as in sports like soccer, volleyball, and gymnastics, which repeatedly put pressure on the knees, or jobs requiring prolonged squatting or kneeling.

However, Bow Wang, M.D. reminds that transarterial embolization (TACE) for arterial inflammation also has its limitations. The main indications are patients with a pain index exceeding 5 points who have not shown significant improvement after more than three months of various treatments.

This treatment is not suitable in the following situations:

1. Severe tendon or ligament damage or rupture

2. Poor kidney function (eGFR < 30 mL/min/1.73m2)

3. Low platelet count, abnormal coagulation function

4. The patient is unable to lie flat for two hours.

5. Pregnancy

Treatment side effects include possible local hematoma and bruising at the puncture site; temporary local discoloration at the embolization site, which will improve and disappear within minutes to one month.

It is recommended that patients undergo a detailed evaluation by a physician to confirm the true source of pain. After thorough discussion with the physician and family to understand the treatment process and related precautions, treatment is more effective.