Plica Syndrome

What is a Plica?

A plica is a fold of synovial membrane most commonly in the anteromedial aspect of the knee. Plica are present in about 50% of the population and are thought to be the remnants of embryonic connective tissue that failed to fully resorb during your foetal development. Luckily, most plicae are asymptomatic.

While your knee potentially has four plica it is the medial plica that is most likely to be symptomatic (Dupont 1997). It runs parallel to your medial patella just below your medial retinaculum and inserts into your fat pad.

What is Plica Syndrome?

Plica syndrome is essentially an inflammed plica. Your plica can catch during:

repetitive knee straightening and bending,

blunt trauma or knee twisting,

fat pad irritation,

altered knee motion,

internal knee derangements eg meniscal tears. (Schindler 2004)

This is particularly the case if you have experienced persistent pain and weakness in the quadriceps muscles. Plica syndrome often does not always occur in isolation, but concurrently with other knee conditions such as meniscal injuries, patellar tendonitis and Osgood-Schlatter’s Disease.

What are the Symptoms of Plica Syndrome?

Plica syndrome can be suspected when you have:

Anteromedial knee pain - esp medial femoral condyle.

Visible and palpably tender plica.

Audible clicking or snap during knee motion - painful arc 30 to 60 degrees. (Dupont 1997).

Positive Duvet test: pain eased by using a duvet between your knees to ease pain in bed.

Pain with activities: ascending and descending stairs, squatting, rising from a chair and/or sitting for extended periods. (Shetty et al 2007).

Quadriceps atrophy is common on chronic cases.

How is Plica Syndrome Diagnosed?

Your physiotherapist will be able to clinically diagnose plica syndrome. It is more important that you have your knee thoroughly assessed by a physiotherapist or sports doctor to exclude other knee pathologies, in particular meniscal injuries.

X-ray may be useful to rule out other associated pathologies but will not identify a plica. MRIs can identify plica inflammation. However, MRI is more useful for diagnosing other pathologies that may be related to the plica irritation. A comprehensive examination by your physiotherapist or sports physician is preferable.

Plica Syndrome Treatment

Studies show that about 60% of patients with plica syndrome will settle successfully with conservative physiotherapy treatment within 6 to 8 weeks. (Lu et al 2010).

Your physiotherapy treatment will aim to:

Reduce pain and inflammation.

Improve patellofemoral (knee cap) alignment via taping, bracing and exercises.

Normalise your muscle lengths.

Strengthen your knee: esp quadriceps (esp VMO) starting with closed-chain exercises and eventually progressing to open-chain exercises

Strengthen your hip and lower limb muscles.

Address foot biomechanics issues.

Improve your proprioception, agility and balance.

Improve your lower limb function and quality of movement eg walking, running, squatting, hopping and landing.

Minimise your chance of re-aggravating your plica syndrome.

We strongly suggest that you discuss your knee injury after a thorough examination from a knee specialist such as a sports physiotherapist, sports physician or knee surgeon.

Plica Surgery

Should your symptoms persist beyond 3 to 6 months, arthroscopic knee surgery for a plica syndrome may be considered. The most successful surgery involves lateral retinacular release to allow the patella to track more medially and thereby alleviate plica irritation as it rolls over the medial femoral condyle. Success rates exceed 85%. (Gerbino et al 2007).

How to Prevent Plica Syndrome?

Since plica syndrome usually occurs concomitantly with other knee conditions, it is important to be proactive in managing your other knee injuries. This involves maintaining normal knee joint alignment, adequate strength and flexibility in the muscles around the knee joint plus the rest of the lower limb.

Ensuring that you wear adequate footwear that supports your foot biomechanics. Also, weight-management can play a role in the pressure exerted on lower limb joints, and thus should be something considered as a long-term preventative measure.

For more advice, please consult your physiotherapist.

Braces for Plica Irritation

Many patients will try a knee brace. Brace that improve patellofemoral joint alignment seem to be the most effective to ease plica-related pain.

Patellofemoral Brace

An effective patellofemoral brace can be useful as an alternative to kneecap taping.