Amidst the hustle and bustle of daily life, minor niggles are often overlooked. However, ignoring such issues can cause discomfort and significantly affect your quality of life over time. The knees, which bear most of our body weight, are involved in almost all our everyday activities, including sitting, standing, bending, walking and running. However, several factors, like poor posture, excess body weight and injuries, can adversely affect them and restrict their range of motion, making it difficult to fully extend or flex the leg. One such condition resulting from these factors is fat pad impingement of the knee, also known as infrapatellar fat pad syndrome. “The fat pad is a fatty tissue that’s located under the kneecap. It acts as a shock absorber,” says Chandan Poddar, consultant physiotherapist, sports medicine department, Sir HN Reliance Foundation Hospital and Research Centre, Mumbai. “It acts like a cushion between the kneecap and the bone underneath. When this fatty tissue gets pinched, inflamed or injured, it leads to fat pad impingement.”
While seemingly inconspicuous, fat pad impingement can cause mobility issues as well as pain and swelling in the knees. “There’s usually pain in the front of the knee underneath the kneecap,” says Poddar. “It’s also accompanied by localized swelling as the impingement leads to inflammation. It’s quite painful to touch as well. Things like kneeling down or standing for a long time, taking the stairs and locking the knees will cause pain.”
Common causes of fat pad impingement
Infrapatellar fat pad syndrome can be caused by various factors, which include:
♦ Trauma or injury: The knees are not designed to take the brunt of falls effectively. “One of the reasons [for fat pad impingement] is external trauma, such as falling on the knees. There’s a direct impact on the kneecap, potentially causing the fat pad to get pinched,” notes Poddar.
♦ Overuse or repetitive stress: Activities that involve frequent bending or extending of the knee joint, such as running, squatting or jumping, can place excess stress on the fat pad and contribute to its irritation. “Repeated movements like knee hyperextension can also injure the fat pad. When we straighten our knees, it’s called extension; however, we sometimes lock our knees fully, which is referred to as hyperextension. If that happens repeatedly, it can cause fat pad impingement,” cautions Poddar.
♦ Biomechanical issues: Abnormalities in the alignment or mechanics of the knee joint, such as wrong patellar tracking or excessive pronation [inward rotation] of the foot, can cause increased pressure on the fat pad. “Some people are more prone to fat pad impingement, including those who are flat-footed or hypermobile [where hypermobility refers to excessive movement of the knee joints]. They may usually lock their knees when they walk or stand,” explains Poddar.
♦ Excessive body weight: Being overweight places the full load of the body on the knee joints, which can irritate the fat pad and lead to impingement.
Diagnosing fat pad impingement
Unlike injuries to other parts of the knee (like the ACL or patellar tendon), diagnosing fat pad impingement is not easy. “It’s very difficult to pinpoint the injury with one particular test as there are many structures in front of the knee. But if you feel pain when you straighten and lock the knee or when you tighten the kneecap, it could be a fat pad impingement,” says Poddar.
A thorough evaluation by a healthcare professional, which can often include MRIs, is necessary to diagnose the underlying cause and determine the most appropriate treatment approach or modality.
How to manage fat pad impingement
According to experts, some measures to treat the condition include:
♦ Rest and activity modification: Modify or tailor your activities to reduce strain on the knees. This may involve using crutches or a knee brace temporarily to offload the fat pad. “We need to prevent further irritation of the fat pad and not perform movements that are triggering the pain, which can include standing for prolonged periods, squatting, kneeling or taking the stairs. Wearing heels can irritate the fad pad as well because your knees are locked and hyperextended,” explains Poddar.
♦ Physical therapy: A physical therapist can design a tailored exercise program to improve knee strength, flexibility and biomechanics. “The first thing we do is correct their posture. We try to strengthen the muscles around the knee [like the calves and hamstrings] so that they don’t go into that hyperextension posture. We also strengthen the glute muscles and the hip muscles,” says Poddar.
♦ Ice and elevation: Applying ice to the affected area can help reduce swelling and pain. Additionally, elevating your leg while resting can also assist with swelling reduction.
♦ Corticosteroid injections: Cortisone shots are an option to treat inflammation of specific joints or tendons, including the fat pad. “If these approaches don’t work, corticosteroid injections can be administered. They are directly injected into the fat pad, which can help reduce the swelling,” says Poddar.
♦ Biomechanical corrections: It’s essential to address biomechanical issues that are contributing to fat pad impingement. “We recommend exercises to correct the mechanics of the muscles around the kneecap so that the load is taken off the fat pad,” says Poddar.
♦ Weight management: Maintaining an ideal body weight through a healthy diet and regular exercise can help reduce stress on the knee joint.
♦ Surgical intervention: “The last line of management is surgery. However, it’s required in rare cases. The injury usually settles with conventional management,” says Poddar. The common surgical approaches include fat pad resection or realignment procedures.
- Fat pad impingement is characterized by pinching, inflammation or injury of the fat pad — a fatty tissue located under the kneecap.
- The condition causes pain and swelling in the anterior part of the knee. It’s also painful to touch.
- Common causes of fat pad impingement include trauma or injury, overuse, biomechanical issues and excess body weight.
- It’s difficult to diagnose the injury with one particular test. Hence, it’s best to consult a healthcare professional.
- Measures like adequate rest, physical therapy, maintaining an ideal body weight and corticosteroid injections can help treat the condition. Surgery is required in rare cases.