Plica Syndrome: Symptoms, Types, Causes and Treatment

Plica syndrome is a frequently overlooked source of joint pain, often misdiagnosed due to its subtle presentation and overlapping symptoms with other joint disorders. Most commonly affecting the knee, but also seen in the elbow, plica syndrome arises when normal synovial folds (plicae) become irritated or inflamed, leading to discomfort and functional limitations. Understanding its symptoms, types, causes, and the full spectrum of treatment options is essential for patients and clinicians alike. This article explores these facets in detail, synthesizing evidence from current research.

Symptoms of Plica Syndrome

Plica syndrome often presents with a constellation of symptoms that can mimic other joint pathologies, making early recognition challenging. Patients commonly experience intermittent or persistent pain, often localized to the anterior aspect of the knee or lateral elbow, accompanied by mechanical symptoms such as clicking or snapping. A careful clinical assessment is crucial for diagnosis.

Symptom	Description	Typical Location	Source(s)
Pain	Dull, intermittent or sharp	Anterior knee, elbow	1 2 3 4 6
Clicking	Audible or palpable clicks	Knee, elbow	1 2 4 6
Swelling	Localized joint effusion	Knee	4 6
Instability	Feeling of giving way	Knee	1 4 6
Locking	Joint catches or locks	Knee	4 6
Tenderness	Pain on palpation	Over plica region	1 4 5

Table 1: Key Symptoms of Plica Syndrome

Common Presentations

• Anterior Knee Pain
  Pain in the front of the knee is the hallmark of plica syndrome, particularly in children, adolescents, and active adults. The pain is often intermittent and aggravated by activity, squatting, or prolonged sitting 1 3 6.

• Mechanical Symptoms
  Clicking, snapping, or a sensation of catching within the joint may occur during flexion and extension. These are especially reported with movement after periods of inactivity 1 2 4.

• Swelling and Effusion
  Some patients notice mild swelling, usually not as pronounced as in more severe intra-articular injuries 4 6.

• Instability and Locking
  A feeling of the knee "giving way" or episodes of locking may be reported, particularly if the plica impinges between moving parts of the joint 1 4 6.

• Localized Tenderness
  Tenderness is often found over the affected plica, especially on the medial or suprapatellar aspect of the knee. In the elbow, tenderness is most pronounced over the radiocapitellar joint 1 2 4 5.

Symptom Variability and Diagnosis

• Variable Onset: Symptoms can develop gradually or follow trauma or increased activity.
• Overlap with Other Conditions: Due to similarities with meniscal injuries, patellofemoral pain syndrome, or ligamentous injuries, plica syndrome is a diagnosis of exclusion 3 4 6.
• Physical Examination: A palpable, thickened band and pain on provocative tests help in clinical suspicion 1 6.

Types of Plica Syndrome

Plicae are embryological remnants present in most joints, but only occasionally do they become symptomatic. In the knee, several distinct types are recognized based on location and morphology. Elbow plica syndrome, though less common, is also notable.

Type	Description	Prevalence/Significance	Source(s)
Medial (Medio-patellar)	Fold along medial knee	Most commonly symptomatic	3 5 6 7 10
Suprapatellar	Above the patella	Frequent, often asymptomatic	4 5 6
Inferior	Anterior to intercondylar notch	Rarely symptomatic	6
Elbow	Radiocapitellar joint plica	Can cause lateral elbow pain	2

Table 2: Types of Plica Syndrome

Medial (Medio-patellar) Plica

• Anatomy: Runs from the medial wall of the knee towards the infrapatellar fat pad.
• Clinical Relevance: Most frequently implicated in symptomatic cases, particularly causing anteromedial knee pain 3 6 7 10.
• Morphology: Five different medial plicae described, varying in size and location 6.

Suprapatellar Plica

• Anatomy: Located above the patella within the suprapatellar pouch.
• Variants: Classified from absent to complete septum types using systems like the Dandy classification 5.
• Clinical Relevance: While common (seen in up to 78% of individuals), only certain morphologies, such as the complete septum, tend to become symptomatic 4 5.
• Diagnosis: Suprapatellar plica syndrome is diagnosed when anterior knee pain, localized tenderness, and imaging findings are present without other pathologies 5.

Inferior Plica

• Anatomy: Found anterior to the intercondylar notch, inserting into the infrapatellar fat pad.
• Significance: Rarely causes symptoms 6.

Elbow Plica Syndrome

• Location: Synovial plicae of the radiocapitellar joint.
• Symptoms: Lateral elbow pain, clicking, and tenderness 2.
• Diagnosis: Best confirmed with MRI and clinical examination.

Causes of Plica Syndrome

Understanding why synovial plicae become symptomatic involves recognizing both intrinsic and extrinsic factors. Not all individuals with plicae experience symptoms; only when these structures are irritated or inflamed do problems arise.

Cause	Mechanism	Typical Trigger	Source(s)
Trauma	Direct blow or injury	Sports, accidents	1 4 7 9 10
Overuse	Repetitive flexion-extension	Running, cycling	6 7
Inflammation	Synovial irritation/swelling	Synovitis, arthritis	4 7
Congenital	Embryonic remnant (structure)	Present from birth	4 5 6 7
Idiopathic	Unknown, no clear cause	—	4

Table 3: Causes of Plica Syndrome

Traumatic Causes

• Direct Trauma: A single blow or twisting injury can inflame or thicken the plica, leading to symptoms 1 4 7 9.
• Sudden Activity Change: Increase in athletic activity, especially in youth or previously sedentary individuals, is a common trigger 7.

Overuse and Repetitive Strain

• Sports Participation: Activities involving repetitive knee flexion and extension, such as running, cycling, and rowing, increase risk 6 7.
• Microtrauma: Chronic microtrauma can result in fibrosis, thickening, and loss of elasticity of the plica 7.

Inflammatory Causes

• Synovitis: Any condition causing joint inflammation can involve the plica, making it more susceptible to irritation 4 7.
• Association with Arthritis: Though less common, inflammatory arthritis may contribute 4.

Congenital and Idiopathic Factors

• Embryological Remnants: Plicae are normal developmental structures; however, certain types (e.g., complete septum) are more likely to become symptomatic 4 5 6 7.
• Idiopathic Cases: Sometimes, no clear cause is identified 4.

Pathophysiology

• Fibrosis and Thickening: Chronic irritation leads to thickened, less elastic plicae that may impinge on joint structures, causing pain and sometimes cartilage damage 7 10.
• Mechanical Impingement: Enlarged plicae can rub against the femoral condyle or patella, or, in the elbow, against the radial head, producing symptoms 2 7.

Treatment of Plica Syndrome

Treatment for plica syndrome is tailored to symptom severity and response to initial therapies. The approach is stepwise, starting with conservative methods before considering surgical intervention.

Treatment	Description	Indication	Source(s)
Rest & Activity Modification	Reduce aggravating activities	First-line	3 4 6 7 8
Physiotherapy	Strengthening, stretching, modalities	Persistent symptoms	1 3 4 6 7
Medication	NSAIDs, corticosteroid injections	Acute inflammation	7
Arthroscopy	Surgical excision of plica	Refractory cases	1 3 4 7 8 9 10

Table 4: Treatment Strategies for Plica Syndrome

Conservative Management

• Rest and Activity Modification: Advising patients to avoid activities that aggravate symptoms (e.g., squatting, running) is a crucial first step 3 4 6 7.
• Physical Therapy: Focuses on reducing inflammation, correcting biomechanical issues, and strengthening periarticular muscles, particularly the quadriceps 1 3 4 6 7.
• Medications: NSAIDs help reduce pain and swelling; corticosteroid injections may be considered for persistent cases 7.
• Duration: Conservative management is typically continued for up to 6 months before considering surgery 3 4.

Surgical Treatment

• Arthroscopic Excision:
  • Indication: Reserved for cases not responding to conservative measures.
  • Technique: The plica is visualized and excised through minimally invasive arthroscopy 1 3 4 7 8 9 10.
  • Outcomes: High rates of symptomatic improvement; better outcomes are seen in younger patients, those with localized symptoms, and absence of cartilage damage 1 7 10.
  • Complications: Generally low, with few recurrences if the entire plica is removed 9 10.
• Open Surgery: Rarely needed; arthroscopic approaches are preferred 7.

Prognosis and Follow-up

• Most patients have good to excellent outcomes with appropriate treatment 1 7 8.
• Long-term results depend on the presence of coexisting cartilage injuries and patient adherence to rehabilitation 10.
• Arthroscopy is both diagnostic and therapeutic, especially when imaging is inconclusive 1 3 4 7.

Conclusion

Plica syndrome, while often under-recognized, is a significant cause of joint pain—most notably in the knee and, less commonly, the elbow. Early recognition and a structured approach to management are key to successful outcomes.

Key Takeaways:

• Plica syndrome presents with anterior joint pain, mechanical symptoms (clicking, catching), and tenderness, typically in the knee 1 3 4 6.
• The medial plica is most commonly symptomatic, but suprapatellar and even elbow plica syndrome can occur 2 3 4 5 6.
• Causes include trauma, repetitive overuse, congenital anatomical variants, and inflammation 1 4 5 6 7.
• Diagnosis is clinical and by exclusion; MRI and arthroscopy are valuable tools 3 4 5 7.
• Treatment begins conservatively (rest, physiotherapy, NSAIDs), with arthroscopic excision reserved for persistent cases 1 3 4 6 7 8 9 10.
• Prognosis is excellent in most cases, especially with early intervention and absence of cartilage damage 1 7 10.

By maintaining a high index of suspicion and following evidence-based protocols, clinicians can ensure optimal recovery for patients with plica syndrome.