The Role of Complete Suprapatellar Plicae Takatomo Mine, M.D., Kazuki Chagawa, M.D., Koichiro Ihara, M.D., Hiroyuki Kawamura, M.D., Ryutaro Kuriyama, M.D., and Ryo Date, M.D.
Abstract: Shelf syndrome mainly affects younger people, often athletes. Cases of complete suprapatellar plica syndrome are rare. Arthroscopic inspection is necessary to diagnose complete suprapatellar plicae. The patients’ symptoms improve after removal of the plicae. Our technique is an easy, completely arthroscopic procedure that has yielded good clinical outcomes in patients who have complete suprapatellar plicae. Although cases of complete suprapatellar plica syndrome are rare, it should be considered in patients with moderate knee pain.
T
he synovial plica of the knee joint is considered a remnant of the septum that existed in the patellofemoral joint during fetal life.1 The synovial plica is classified into four distinct anatomic patterns: superior, medial, inferior, and lateral. In particular, a medial patellar plica is called a “shelf” and is a well-known disease.2 A suprapatellar plica, which is little known, divides the suprapatellar pouch from the remainder of the knee. It is said that in complete type, symptoms occur. We present our technique for arthroscopic diagnosis and treatment of complete suprapatellar plica syndrome. Our surgical technique is an easy, completely arthroscopic procedure that has yielded good clinical outcomes in patients whose symptoms were considered to be caused by complete suprapatellar plicae.
magnetic resonance imaging shows a band-like structure that exhibits low signal intensity above the patella, but it is not depicted clearly on a T2-weighted spin-echo image (Fig 1). The condition of a complete
Surgical Technique The patient is placed supine on the operating room table. A standard anterolateral viewing portal and anteromedial working portal are created. We use a standard 30 arthroscope and a pump system. Arthroscopic examination shows a complete suprapatellar plica above the patellofemoral joint in the suprapatellar bursa (Video 1). Preoperative From the Department of Orthopaedic Surgery, Kanmon Medical Center, Yamaguchi, Japan. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received July 9, 2015; accepted October 26, 2015. Address correspondence to Takatomo Mine, M.D., 1-1 Chofusotoura, Shimonoseki, Yamaguchi 751-8501, Japan. E-mail: minet@kanmon-mc2. hosp.go.jp Ó 2016 by the Arthroscopy Association of North America 2212-6287/15632/$36.00 http://dx.doi.org/10.1016/j.eats.2015.10.022
Fig 1. Preoperative magnetic resonance imaging (right knee, T2-weighted spin-echo image, sagittal view) showed a bandlike low-signal structure (arrow) above the patella that was not depicted clearly.
Arthroscopy Techniques, Vol 5, No 1 (February), 2016: pp e197-e199
e197
e198
T. MINE ET AL.
Fig 2. Arthroscopic view from anterolateral portal. A complete suprapatellar plica (arrow) was noted above the patellofemoral joint. (A) The plica generally exhibited a uniform thickness; however, some regions were slightly thicker than others. (B) The central portion of the plica was thinner than its peripheral region.
suprapatellar plica is observed (Fig 2). The plica does not exhibit a uniform thickness; some regions are slightly thicker than others. The complete suprapatellar plica is released gradually with a radiofrequency device (ArthroCare, Sunnyvale, CA) inserted through the anterolateral portal (Fig 3). The released plica is removed piece by piece with a punch (Duckling Upbiter; Smith & Nephew, Andover, MA) inserted through the anterolateral portal (Table 1). Postoperatively, immediate weight bearing and range of motion are allowed. The knee pain disappears after surgery, and the patient is able to resume daily activities, with sporting activity being allowed at 1 to 2 months after surgery.
Fig 3. (A) The complete suprapatellar plica was released gradually with a radiofrequency device. (B) The released plica was removed piece by piece with a punch. (C) Condition after plica removal.
Discussion Medial and lateral alar folds are found between the patellofemoral joint space and the medial and lateral femorotibial joint spaces, and the “shelf” refers to the medial alar fold extending and ascending the medial joint wall toward the suprapatellar synovial plica, which exhibits a shelf-like appearance.1,3 Suprapatellar plicae, which are little known, divide the suprapatellar pouch from the remainder of the knee. It is said that cases of complete suprapatellar plicae produce symptoms. The pathophysiology of plica syndrome is not clearly defined but can generally be described as follows: In the presence of inflammation associated with edema and thickening, the plica can become relatively
e199
COMPLETE SUPRAPATELLAR PLICA Table 1. Tips and Pearls of Procedure Arthroscopic diagnosis of complete suprapatellar plica syndrome is made. For the surgical procedure, resection is performed with a radiofrequency device and a punch inserted through an anteromedial portal. The indication for our technique is a patient whose symptoms are considered to be caused by a complete suprapatellar plica.
inelastic and eventually symptomatic as it snaps over the femoral condyle. This results in secondary mechanical synovitis and erosion around the margins of the condyle. Hughston et al.4 reported that pain can develop when complete suprapatellar plicae are subjected to inflammation and scarring, whereas Strover et al.5 suggested that the pain was caused by impingement between the quadriceps tendon and the medial condyle. On the other hand, Hardaker et al.6 reported that it was caused by patellar malalignment due to hypertrophy and fibrillation of the plica. Regarding the pathogenic mechanism of suprapatellar plica syndrome, it has been suggested that decreased flexibility and retractility of the suprapatellar plica and enhanced irritability of the joint capsule are involved. The plica does not exhibit a uniform thickness; some regions are slightly thicker than others. These variations in the thickness of the plica are considered to be caused by inflammation and scarring of the complete suprapatellar plica over a long period. The clinical characteristics of suprapatellar plica syndrome are poorly understood, and so, it is difficult to diagnose the condition without arthroscopy. The
conditions of the patients described in this study did not improve after nonsurgical treatment at other hospitals. The advantage of the described technique is that it is an easy, completely arthroscopic procedure. The candidate is a patient whose symptoms are considered to be caused by complete suprapatellar plicae. The disadvantage is that preoperative diagnosis of complete suprapatellar plicae is difficult. Although cases of complete suprapatellar plica syndrome are rare, this condition should be considered in patients in whom persistent pain develops around the patellofemoral joint, as was found in the cases reported in this article.
References 1. Dandy DJ. Anatomy of the medial suprapatellar plica and medial synovial shelf. Arthroscopy 1990;6:79-85. 2. Nottage WM, Sprague NF III, Auerbach BJ, Shahriaree H. The medial patellar plica syndrome. Am J Sports Med 1983;11:211-214. 3. Sakakibara J. Arthroscopic study on Ino’s band (plica synovialis mediopatellaris). J Jpn Orthop Assoc 1974;50: 513-522. 4. Hughston JC, Stone M, Andrew JR. The suprapatellar plica: Its role in internal derangement of the knee. J Bone Joint Surg Am 1973;55:13-18. 5. Strover AE, Rouholamin E, Guirguis N, Behdad H. An arthroscopic technique of demonstrating the pathomechanics of the suprapatellar plica. Arthroscopy 1991;7: 308-310. 6. Hardaker W Jr, Whipple TL, Bassett FH III. Diagnosis and treatment of the plica syndrome of the knee. J Bone Joint Surg Am 1980;62:221-225.