What Is Plica Syndrome?


Plica syndrome, an uncommon yet significant knee condition, brings forth challenges in both diagnosis and management. The term "plica" refers to a fold in the synovial lining of the knee joint, and when this fold becomes irritated or inflamed, it can lead to a range of symptoms impacting knee function. This article aims to provide insights into the intricacies of plica syndrome, shedding light on its causes, symptoms, diagnosis, and potential treatment approaches.1

Unravelling the complexities of plica syndrome

Plica syndrome is characterised by the irritation or inflammation of the plica, a fold in the synovial membrane that lines the knee joint. While the precise cause of plica irritation can vary, it is often associated with overuse, trauma, or repetitive knee movements. The plica itself is a remnant of foetal development that usually diminishes as a person grows. However, in some individuals, it persists and can lead to symptoms associated with plica syndrome.1

Symptoms and manifestations

Pain and swelling

Visual representation: Persistent pain and swelling in the knee region are hallmark features of plica syndrome.

Description: Individuals with plica syndrome often experience discomfort, especially during or after activities that involve bending or extending the knee.

Clicking sensation

Visual representation: Some patients may report a clicking or popping sensation when moving the knee.

Description: The plica's irritation can cause friction within the joint, resulting in audible or palpable sensations.

Limited range of motion

Visual representation: Reduced flexibility and limited range of motion in the affected knee.

Description: Plica syndrome can hinder smooth movement, leading to stiffness and limitations in performing regular activities.

Localised tenderness

Visual representation: Tenderness over the plica site when palpated.

Description: Direct pressure on the plica can elicit tenderness, aiding in clinical diagnosis.

Diagnosing plica syndrome

Healthcare providers conduct a thorough examination, assessing the patient's medical history, symptoms, and conducting a physical examination.

Imaging studies

  • Magnetic Resonance Imaging (MRI) or ultrasound may be employed to visualise the knee joint's internal structures, confirming the presence of an irritated plica.1


  • In some cases, arthroscopic surgery may be recommended for both diagnosis and treatment. This minimally invasive procedure allows direct visualisation of the joint and the plica.1

When diagnosing plica syndrome, physical examination demonstrates 90% sensitivity and 89% specificity, ultrasound exhibits 90% sensitivity and 83% specificity, MRI shows 77% sensitivity and 58% specificity, with arthroscopy being considered the gold standard for accurate diagnosis.1

Treatment and management of plica syndrome

Conservative measures

  • Non-surgical approaches often include rest, ice, compression, and elevation (RICE) to alleviate symptoms.2
  • Physical therapy may be recommended to strengthen the muscles surrounding the knee and improve joint stability.2

Anti-inflammatory medications

  • Nonsteroidal anti-inflammatory drugs (NSAIDs) can be prescribed to reduce inflammation and manage pain.2

Corticosteroid injections

  • In some cases, corticosteroid injections may be administered directly into the knee joint to alleviate inflammation.2

Arthroscopic surgery

  • If conservative measures prove ineffective, arthroscopic surgery may be considered to address the irritated plica directly.2

Recent research and advancements

Diagnostic innovations

  • Advanced imaging techniques: Ongoing research explores the use of advanced imaging techniques such as high-resolution ultrasound and dynamic MRI sequences to enhance the accuracy of diagnosing plica syndrome. These methods aim to provide detailed insights into the dynamics of the knee joint during movement, aiding in the identification of irritated or inflamed plica.2
  • Biomarkers: Researchers are investigating potential biomarkers associated with plica syndrome. Identifying specific biomarkers in blood or synovial fluid could contribute to more precise and non-invasive diagnostic methods.

Regenerative therapies

  • Platelet-Rich Plasma (PRP): Some studies explore the use of PRP injections as a regenerative therapy for plica syndrome. PRP, derived from the patient's own blood, contains growth factors that may stimulate tissue healing and reduce inflammation. This approach aims to promote natural healing processes in the irritated plica.3
  • Stem Cell Therapy: Investigating the potential of stem cell therapy for promoting tissue regeneration in the knee joint is an area of interest. Stem cells have the capacity to differentiate into various cell types, and their application in orthopaedics is an evolving field.

Patient-specific treatment plans

  • Personalised physical therapy: Tailoring physical therapy programs to the individual characteristics of each patient is an area of ongoing research. Patient-specific exercises and rehabilitation plans aim to address the unique biomechanical factors contributing to plica irritation.
  • Precision medicine approaches: Advancements in precision medicine may lead to the development of individualised treatment strategies based on genetic, molecular, and biomechanical profiles. This approach considers the specific characteristics of each patient's condition, optimising therapeutic outcomes.

Long-term outcomes and quality of life

  • Longitudinal studies: Research is increasingly focusing on conducting longitudinal studies to assess the long-term outcomes of individuals with plica syndrome. Understanding the natural course of the condition and factors influencing prognosis is essential for refining treatment strategies.
  • Patient-reported outcomes: Incorporating patient-reported outcomes and quality-of-life assessments into research studies provides valuable insights into the impact of plica syndrome on daily activities, mental well-being, and overall quality of life.
  • A study of 969 patients found that, with appropriate treatment, 64% were symptom-free at a median follow-up of 27.5 months.

Surgical innovations

  • Arthroscopic techniques: Advancements in arthroscopic techniques continue to refine the surgical management of plica syndrome. Research explores novel approaches and tools to enhance the precision and effectiveness of arthroscopic procedures.
  • Rehabilitation protocols: Research is dedicated to optimising post-surgical rehabilitation protocols. Tailored rehabilitation programs aim to promote optimal recovery, prevent complications, and improve long-term functional outcomes.


Ongoing research endeavours are expanding our understanding of plica syndrome, from refined diagnostic methods to innovative therapeutic approaches. The collaborative efforts of clinicians, researchers, and patients contribute to the continuous evolution of knowledge in the field. As these advancements progress, the hope is to enhance diagnostic accuracy, refine treatment strategies, and ultimately improve the outcomes and quality of life for individuals affected by plica syndrome.


  1. Casadei, Kyle, and John Kiel. ‘Plica Syndrome’. StatPearls, StatPearls Publishing, 2023. PubMed, Available from: http://www.ncbi.nlm.nih.gov/books/NBK535362/.
  2. Lee, Paul Yuh Feng, et al. ‘Synovial Plica Syndrome of the Knee: A Commonly Overlooked Cause of Anterior Knee Pain’. The Surgery Journal, vol. 3, no. 1, Feb. 2017, pp. e9–16. PubMed Central, Available from: https://doi.org/10.1055/s-0037-1598047.
  3. Lox, Dr. ‘Plica Syndrome’. Dr. Dennis Lox Stem Cell Therapy, Available from: https://www.drlox.com/medical-co nditions-treated/knee-conditions/plica-syndrome/. Accessed 18 Nov. 2023.
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Dafydd Thomas

MSc, Genomic Medicine, The University of Manchester, UK

As a Genomic Medicine student pursuing an MSc at Manchester University, my academic journey is rooted in the realm of biochemistry, with a specialized focus on genetics and the intricacies of rare diseases. Throughout my academic pursuits, I've gained valuable insights into the field of genomics and its applications in medicine. I am committed to sharing advancements in genomic medicine and to delve into cutting-edge research and emerging technologies. With a keen interest in the genetic nuances of rare diseases, I aspire to contribute meaningfully to the field and bridge the gap between genomic knowledge and its clinical implications.

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