Suprapatellar Plica Research Articles

Anterior Knee Pain: Plica syndrome, the forgotten pathology?

Summary The following article is a literature review of plica syndrome. It demonstrates that although it is not commonly diagnosed in clinical practice, its occurrence and relevance are important and should not be excluded from a knee examination. Further, if the fundamentals of plica syndrome can be understood, this may lead to a greater success in diagnosis and management. A synovial plica is a shelf-like membrane between the synovium of the patella and the tibiofemoral joint. Three plicae are found in the knee: suprapatellar, medial and inferior. A symptomatic plica causes pain, clicking, effusion, instability and locking of the patellofemoral joint. It is common in teenagers, more so in women than in men. A suprapatellar plica is found generally within the suprapatellar pouch and its occurrence ranges from 65% to 78%. Medial plicae are commonly found between the medial border of the patella and medial femoral condyle and are the most problematic. There are five medial plicae, all found in different anatomical positions. The inferior plica is found anterior to the intercondylar notch inserting into the infrapatellar fat pad. Mechanism of injury is varied, but principally repeated flexion-extension movements such as those seen in cycling, running and rowing sports can exacerbate the asymptomatic plicae. The pathophysiology constitutes repetitive microtrauma causing fibrosis and thickening of the synovium, inflammation and fluid production and increases articular pressure and loose bodies within the patellofemoral joint. This can mimic an internal derangement of the knee and can be mistaken for a torn anterior cruciate ligament on arthroscopy. Clinical examination may reveal some mal-tracking of the patella and in some cases the plicae may be palpable. Several tests are discussed in the text. Conservative treatment is advocated initially, including physiotherapy to help reduce inflammation. Arthroscopy and resection are also implicated in some cases. These are further discussed. The literature review of plica syndrome was initiated using a Medline search (1940-1999) using the key words ‘plicae', ‘patellofemoral pain' and ‘anterior knee pain'.

Arch type pathologic suprapatellar plica

The authors encountered a case of arch type pathologic suprapatellar plica that was excised using an arthroscopic technique. It is reported with a review of the literature.Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 17, No 5 (May-June), 2001: pp 536–538

The clinical significance of the complete type of suprapatellar membrane

The plicae are synovial septa remaining in adult life that existed in early fetal life. The suprapatellar plica separates the suprapatellar pouch from the knee joint. The plica syndrome has clinical significance, which has been occasionally overlooked, but the pathophysiology of symptomatic plicae may be hard to explain. To evaluate the clinical significance of the suprapatellar plicae, the authors reviewed 34 cases in 23 patients with vague pain around the knee and a total septum of the suprapatellar plica at arthroscopic examination from September 1991 to December 1993. The follow-up period was from 6 months to 2 years and 9 months. The most common presenting symptom was chronic mild knee pain, aggravated by prolonged squatting or standing, with other patients reporting recurrent swelling, instability, giving-way, or a feeling of snapping. The objective findings include palpable band on the superomedial side, audible snapping, and local tenderness, but there were no significant abnormal findings in the laboratory. The radiographic findings were few, with sclerosis of the articular surface of the patella in 2(6%), malalignment in 1(3%), and mild degenerative change in 4 cases(12%). Five of 11 patients evaluated by bone scan had increased uptake around the patellofemoral joint, and 7 of 13 knees had a relatively small suprapatellar bursa on conventional arthrogram or pneumoarthrogram. At arthroscopy, a suprapatellar plicae with complete septum was identified in 30 of 34 cases (88%) and associated lesions presented as meniscal tears, loose body, and discoid meniscus without tear. The complete plicae were surgically excised under arthroscopic control in 30 patients and the results were excellent in 22 patients (73%), good in 5 (17%), and poor in 3 (10%)at 17 months follow-up; there were no failures. In our opinion, the complete suprapatellar plica is clinically significant in patients who have equivocal diagnosis of knee problems and further studies of the pathophysiology of complete suprapatellar plica are needed. (Arthroscopy 1998 Nov-Dec;14(8):830-5.)

Arthroscopic findings of the synovial plicae of the knee

From June 1991 to March 1993, 400 knees in 363 patients were studied arthroscopically to clarify the arthroscopic anatomy of the plica and determine the classification of the plica. The various patterns of the synovial plicae were classified according to their shape and size from the arthroscopic view. Incidences of the synovial plica at the knees were: suprapatellar plica, 87.0%; mediopatellar plica, 72.0%; infrapatellar plica, 86.0%; and lateral patellar plica, 1.3%. There was no significant correlation in frequencies and distributions of patterns among the four groups of the plica, between men and women, with age, and between right and left. However the significant similarity in patterns of the right and left knees in the same persons was noted.

Suprapatellar plicae of the knee presenting as a soft-tissue mass report of five patients

It is well recognized that synovial plicae can lead to clinical manifestations that simulate internal derangements of the knee, meniscal tears, or arthritis. Such plicae, however, also can lead to compartmentalization of the joint. We report on five patients with abnormal suprapatellar plicae that led to joint compartmentalization and distention of the suprapatellar bursa manifested as a soft-tissue mass.

Medial patellar plica (A morphological study in neonatal cadavers)

In this study 100 knees of 50 neonatal cadavers were examined morphologically. The patellar plica was seen in 18 knees (18%) in this series. And the medial patellar plicae were in the from of the distal extentions of the suprapatellar plicae in all cases.

An arthroscopic technique of demonstrating the pathomechanics of the suprapatellar plica

The suprapatellar plica or incomplete suprapatellar septum of the knee is a recognized cause of knee pain in some patients and appears to exist in others without causing any symptoms. To date no clear method of demonstrating the pathomechanics of the suprapatellar plica by arthroscopic means has been described. This article describes a new technique of visualizing this structure arthroscopically and demonstrating the mechanism of its morbidity. By the use of a proximal viewpoint via the lateral suprapatellar portal, we have shown that the suprapatellar plica impinges on the medial femoral condyle and is trapped between the quadriceps mechanism and the femoral trochlea when the knee is flexed beyond 70°. We conclude that our arthroscopic method may show the mechanism of production of symptoms of the pathological suprapatellar plica.

The development of synovial plicae in human knee joints: An embryologic study

An embryologic study about the development of the human knee joint cavity was carried out with special attention to the formation of synovial plicae, using a total of 116 knees of embryos and fetuses. The incidence of synovial plicae in the fetal stage was also investigated. Formation of joint space starts at the middle of the interzone at around 8 weeks of gestation. Multiple small cavitations around the femoral condyle and patella coalesce to form larger cavitations. At around 10 1/2 weeks, the knee joint consists of a single cavity with synovial lining. At certain sites, such as at the medial part of patello-femoral and the infrapatellar regions, mesenchymal tissue strands remain. They may become plica. In the fetal stage from 11 to 20 weeks, an infrapatellar plica was found in 50% of specimens, a suprapatellar plica in 33%, and a mediopatellar plica in 37%. Only the infrapatellar plica showed a decrease in incidence.

Anatomy of the medial suprapatellar plica and medial synovial shelf

The anatomy of the medial suprapatellar plica and medial synovial shelf was studied arthroscopically in 500 knees. The medial suprapatellar plica extended up to one third of the way across the suprapatellar pouch in 64.2% of knees, between one and two thirds in 4%, and two thirds or more in 31.6%. The medial synovial shelf was absent or vestigial in 36% of knees and broader than 1 cm in 13.2%. When both knees were examined arthroscopically, the similarity between the appearances of the plica and the shelf in the two knees was statistically significant. No relationship between age and the pattern of plica or shelf could be found. There was no association between large plicae and large shelves, but the shelf was absent significantly more often in knees with a narrow plica.

The superolateral approach: A better view of the medial patellar plica

When attempting to perform medial patellar plica surgery, the arthroscopist often finds that the three standard portals, namely, central, inferolateral, and midpatella lateral, offer poor visualization, awkward instrumentation, or both. This article suggests and describes the superolateral approach as a better arthroscopic portal for medial patellar plica surgery; while affording a sweeping, unobstructed view of the entire plica, this approach enables the arthroscopist to utilize the midpatella lateral portal for effective and convenient excision, with no damage to articular surfaces. The superolateral approach also offers excellent visualization of the suprapatellar pouch, the suprapatellar plica, and the patellofemoral joint. We further recommend the use of an infusion pump to improve knee distension, as well as the use of arthroscopic electrocoagulation to minimize postoperative hemarthrosis.

Arthrography (Plica Views)

In 45 patients with chronic knee problems arthrograms of the knee were obtained with emphasis on plica views. Thirty arthrograms showed radiographic evidence of plica syndrome. Three patients had thin bands in the proximal part of the suprapatellar pouch. Four patients had infrapatellar plicae. Eighteen patients had suprapatellar plicae, and five had mediopatellar plicae. The cross-table lateral view of the knee in different degrees of flexion is a valuable prognostic method. Five patients with suprapatellar plicae demonstrated excursion of the thick fibrotic band over the anteromedial femoral condyle during arthrography with the knee in different degrees of flexion. These patients did not respond to conservative treatment and required surgical excision of the plicae. Cross-table anteroposterior and tangential views with the medial side of the knee facing upward demonstrate impingement of the medial femoral condyle or the medial facet joint of the patella by the fibrotic mediopatellar plica. All patients (5 of 5) with mediopatellar plicae required surgical excision of the plicae.

The importance of the mediopatellar synovial plica for chondromalacia patellae.

In 60 autopsy knee joints findings on morphology and topography of medio- and suprapatellar plicae and level of insertion of the medial vastus muscle in relation to localization and degree of severity of chondromalacia were determined. The middle fields were affected most frequently and severely with 70% (chondromalacia class II and III). Thirty specimen with mediopatellar plica could be identified out of which 29 (97%) had class II or III chondromalacia; out of 30 specimen without a plica 18 (60%) showed chondromalacia. Accordingly a significant correlation could be detected between the incidence of chondromalacia and that of a mediopatellar synovial plica. When measuring the level of insertion of the medial vastus muscle class III chondromalacia showed an average level of insertion of 11%, class II of 22%, and class O or I of 30%. These differences are statistically significant. Patellar index, patellar facet angle, and patellar depth angle did not show any direct correlation to chondromalacia. The question arises whether the involution anomaly of the genicular septa and the muscular changes are not a manifestation of the same developmental disorder, thus creating the basis for an imbalance of the dynamic functional structure.

Synovial plicae of the knee.

This report describes the anatomy, pathophysiology, clinical, and radiographic findings, and treatment of the synovial plicae of the knee joint. The suprapatellar plica is a synovial fold present in the suprapatellar pouch of the knee joint in approximately 20% of the population. This fold may become symptomatic after injury and cause symptoms similar to other common internal derangements of the knee. Double contrast arthrography of the knee can be used to identify the presence of plicae. Although arthrography can identify the presence of a plica, its clinical significance requires close correlation with symptoms and an accurate clinical examination.

LESIONS OF THE SUPRAPATELLAR PLICA

1. In 78 per cent. of adult knees, a suprapatellar synovial plica exists, representing the fusion of the suprapatellar bursa with the knee joint.2. In pneumo-arthrograms the density of the suprapatellar plica serves as an index of synovial reaction, and is of value in prognosis.3. Fibrosis, hyaliniz