Fat Pad Syndrome
Original Editor - Mariam Hashem
Top Contributors - Mariam Hashem, Tarina van der Stockt, Kim Jackson, Tony Lowe, Simisola Ajeyalemi, Uchechukwu Chukwuemeka, Jess Bell, Marleen Moll, Robin Tacchetti, Rishika Babburu and Wanda van Niekerk
Anatomy and Biomechanics[edit | edit source]
Infrapatellar fat pad has been considered as a source of anterior knee pain. A differentiated diagnosis came later as symptoms and diagnostic modalities showed clear evidence of a distinctive pathology yielding practical application to its management.
The infrapatellar fat pad is an intra-articular extra synovial structure occupying the whole anterior part of the knee joint in all joint positions[1].
Boundaries:
- Superiorly by the inferior pole of the patella,
- Inferiorly by the anterior tibia, intermeniscal ligament, meniscal horns and infrapatellar bursa,
- Anteriorly by the patellar tendon
- Posteriorly by the femoral condyles and intercondylar notch
Attachments:
- The intercondylar notch via the ligamentum mucosum,
- Anterior horns of the menisci
- The proximal end of the patella tendon
- The inferior pole of the patella
Supplied mainly by the posterior tibial nerve. The infrapatellar fat pad can be a source of both localized and sever pain this could be attributed to the presence of type VIa nerve endings[2] which could be activated through mechanical deformation or chemical pain mediators. Substance P-nerve fibers is also present in individuals with anterior knee pain, particularly when the infrapatellar fat pad is inflamed[3]. As a potential source of inflammation and pain, some authors considered the fat pad to be a key structure in patellar tendinopathy[4] and osteoarthritis[5].
Numerous studies investigated the influence of the fat pad on knee mechanics. Earlier studies reported fat pad to be a lubricant structure that facilitated the flow of synovial fluid inside the joint[1]. Later, it became clear that the role of the fat pad yields more sophisticated functions due to the complex neurovascular supply of the structure. A study showed reduced coordination between medial and lateral vastus muscle motor units in anterior knee pain[6]. Another reported a a significantly later activation and reduced amplitude of contraction of quadriceps during stair stepping following injecting the fat pad with a painful hypertonic saline[7]. The inhibited fat pad resulted in increased patellofemoral loading and reduced quadricpes activation[1]. However, the exact association of fat pad and knee biomechanics needs further investigations.
Diagnosis[edit | edit source]
Metabolic Role of the Infrapatellar Fat Pad[edit | edit source]
Acute Fat Pad Syndrome[edit | edit source]
Chronic Fat Pad Syndrome[edit | edit source]
References[edit | edit source]
- ↑ 1.0 1.1 1.2 Mr James MA, Bhatti W, ANAND MS. Infrapatellar fat pad syndrome: a review of anatomy, function, treatment and dynamics. Acta Orthopaedica Belgica. 2016;82:1-2016.
- ↑ Bohnsack M, Wilharm A, Hurschler C, Rühmann O, Stukenborg-Colsman C, Joachim Wirth C. Biomechanical and kinematic influences of a total infrapatellar fat pad resection on the knee. The American journal of sports medicine. 2004 Dec;32(8):1873-80.
- ↑ Bohnsack M, Meier F, Walter GF, Hurschler C, Schmolke S, Wirth CJ, Rühmann O. Distribution of substance-P nerves inside the infrapatellar fat pad and the adjacent synovial tissue: a neurohistological approach to anterior knee pain syndrome. Archives of orthopaedic and trauma surgery. 2005 Nov 1;125(9):592-7.
- ↑ Culvenor AG, Cook JL, Warden SJ, Crossley KM. Infrapatellar fat pad size, but not patellar alignment, is associated with patellar tendinopathy. Scandinavian journal of medicine & science in sports. 2011 Dec;21(6):e405-11.
- ↑ Clockaerts S, Bastiaansen-Jenniskens YM, Runhaar J, Van Osch GJ, Van Offel JF, Verhaar JA, De Clerck LS, Somville J. The infrapatellar fat pad should be considered as an active osteoarthritic joint tissue: a narrative review. Osteoarthritis and Cartilage. 2010 Jul 1;18(7):876-82.
- ↑ Mellor R, Hodges PW. Motor unit syncronization is reduced in anterior knee pain. The Journal of pain. 2005 Aug 1;6(8):550-8.
- ↑ Hodges PW, Mellor R, Crossley K, Bennell K. Pain induced by injection of hypertonic saline into the infrapatellar fat pad and effect on coordination of the quadriceps muscles. Arthritis Care & Research. 2009 Jan 15;61(1):70-7.
