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Medial Synovial Plica Irritation excerpt
Article Last Updated: Apr 14, 2005
Excerpt
from Plica Syndrome
Synonyms, Key Words, and Related Terms: medial synovial shelf, medial
shelf, synovial chorda, medial pleat, Iino's band, Iino band, Aoki's ledge,
Aoki ledge, medial intraarticular band, meniscus of the patella,
mediopatellar pseudomeniscus, plica synovialis mediopatellaris, plica
synovialis suprapatellaris, superomedial plica, medial suprapatellar plica,
plica alaris elongata, ligamentum mucosum, plica synovialis patellaris,
plica synovialis patellae, infrapatellar plica, infrapatellar fold,
infrapatellar septum, knee pain
Please see middle of page #2 for the full topic text: Plica Syndrome
Plica syndrome of the knee is a constellation of signs and symptoms that occur secondary to injury or overuse. An otherwise normal structure, a plica can be a significant source of anterior knee pain. Once an inflammatory process is established, the normal plical tissue may hypertrophy into a truly pathological structure (see Image 1). This article provides an overview of pertinent anatomy as well as diagnosis and treatment of plica syndrome of the knee.
During embryonic development, the knee is initially divided into 3 completely separate compartments. Synovial membranes divide the compartments. By the third or fourth month of fetal life, the membranes are resorbed, and the knee becomes a single chamber. If the membranes resorb incompletely, various degrees of septation may persist. These embryonic remnants are known as synovial plicae. Four types of synovial plicae of the knee have been described in the literature.
The suprapatellar plica, or plica synovialis suprapatellaris, divides the suprapatellar pouch from the remainder of the knee. Rarely, this plica may initiate a suprapatellar bursitis or perhaps chondromalacia, and symptoms secondary to these conditions may be present. Anatomically, the suprapatellar plica can be complete or in the form of a porta, which only partially separates the compartments. It courses from the anterior femoral metaphysis or the posterior quadriceps tendon to the medial wall of the joint. The suprapatellar plica most commonly begins proximal to the superior pole of the patella but may begin anywhere.
The mediopatellar plica is the most frequently cited cause of plica syndrome. It lies on the medial wall of the joint, originating suprapatellar and courses obliquely down to insert on the infrapatellar fat pad. This plica, sometimes known as a shelf, lies in the coronal plane.
The rare and poorly documented lateral synovial plica is a wider and thicker band than the medial plica. It is located along the lateral parapatellar synovium, inserting on the lateral patellar facet. The lateral plica has been argued to be derived from the parapatellar adipose synovial fringe rather than being a vestigial septum.
The plica found to be the least symptomatic of all, the infrapatellar plica or ligamentum mucosum, is ironically the most commonly encountered plica. Some authors even claim this plica is never responsible for plica syndrome. This bell-shaped remnant originates in the intercondylar notch, widens as it sweeps through the anterior joint space, and attaches to the infrapatellar fat pad. This plica’s ability to obscure portal entry sites or interfere with visualization during arthroscopy is touted as its only significance.
For excellent patient education resources, visit eMedicine’s Foot, Ankle, Knee, and Hip Center, Arthritis Center, and Bone Health Center. Also, see eMedicine’s patient education article Knee Pain.
History of the Procedure: Both the normal and pathologic aspects of various synovial plicae became readily apparent to orthopaedic surgeons with the advent of arthroscopy. Arthroscopy is a Japanese innovation that changed the face of orthopaedics forever. Kenji Takagi (1888-1963) and Masaki Wantanabe and others in Japan drove its early development, and early adopters in North America, such as Robert Jackson and Lanny Johnson, helped popularize this technology.
The word plica comes from the Latin word meaning fold. This term is simply descriptive in nature, as there is no empiric evidence that true folding of the synovial lining ever occurs. The medial para .....
Medial Synovial Plica Irritation
Article Last Updated: Apr 14, 2005
Section 1 of 10
AUTHOR AND EDITOR INFORMATION
Author: Robert F LaPrade, MD, PhD, Professor, Department of Orthopedic
Surgery, Divisions of Sports Medicine and Shoulder Services, University of
Minnesota
Robert F LaPrade is a member of the following medical societies:
American Academy of Orthopaedic Surgeons,
American Orthopaedic Society for Sports Medicine, and
Arthroscopy Association of North America
Editors: Anthony J Saglimbeni, MD, Medical Director, Center for Sports
Medicine, O'Connor Hospital; Francisco Talavera, PharmD, PhD, Senior
Pharmacy Editor, eMedicine; Marlene DeMaio, MD, Consulting Staff, Assistant
Professor, Department of Orthopedic Surgery, Bone & Joint/Sports Medicine
Institute, Naval Medical Center; Jon Whitehurst, MD, Consulting Staff,
Rockford Orthopedic Associates; William Jay Bryan, MD, Clinical Professor,
Department of Orthopedic Surgery, Baylor University College of Medicine
Author and Editor Disclosure
Synonyms and related keywords: suprapatellar plica, medial
retinaculum
Section 2 of 10
INTRODUCTION
Background
The medial suprapatellar plica of the knee is an intra-articular synovial fold on the medial aspect of the knee. This plica is one of the most common sources of knee pain in patients. In most patients, a proper rehabilitation program allows patients to recover from the symptoms associated with irritation of this structure.
Frequency
United States
No exact numbers on the incidence of patients with an irritated synovial plica are available; however, it is estimated that approximately 50% of patients who present with knee pain to a physician's office have some irritation of their patellofemoral joint. In this group of patients, most of them have some amount of suprapatellar plical irritation.
Functional Anatomy
The suprapatellar plica is an intra-articular synovial fold, which has its main component on the medial aspect of the knee. When the knee is in full extension, the suprapatellar plica commonly forms a shelf, which can be palpated by an examiner. Proximally, the plica is attached to the articularis genu muscle. Distally, it is attached to the anterior horn of the medial meniscus and the medial edge of the retropatellar fat pad. In some patients, this plical shelf can become fibrotic and may impinge on the medial edge of the medial femoral condyle.
Sport Specific Biomechanics
The quadriceps muscles and the articularis genu muscle dynamically control the medial suprapatellar plica. Good quadriceps tone seems to result in normal motion of this plica, while patients with poor quadriceps tone or tight hamstring muscles (antagonists of the quadriceps) commonly have irritation of their synovial plica.
Section 3 of 10
CLINICAL
History
- Medial suprapatellar plical irritation is a common finding in patients who present with complaints of anterior knee pain.
·
- Symptoms include complaints of pain and stiffness over the anteromedial aspect of the knee upon arising from a prolonged sitting position, pain going up and/or down stairs, and pain with prolonged walking.
- The symptoms often wax and wane over periods of time until the patient presents to a physician's office because of continued irritation.
- Some patients may have had a previous arthroscopy for complaints of medial sided knee pain with no alleviation of their symptoms after the arthroscopy, whether they had some medial meniscus or medial compartment articular cartilage pathology addressed at the time of their arthroscopy. Those patients usually did not have physical therapy or an exercise program either before or after this surgery.
Physical
- The examiner can palpate the plica by rolling one's fingers along the tissue between the medial epicondyle and the medial border of the patella. The plica is most commonly palpated about 1-2 fingerbreadths medial to the medial edge of the patella. In this position, the plica can be rolled under the examiner's fingers.
- Pain and irritation upon rolling the medial suprapatellar plica under one's fingers is a classic finding on physical examination. The examiner should ascertain whether this pain is due to him or her palpating this well-innervated area of the synovium or if it is the type of pain that the patient experiences with activities that is being produced by the examiner.
Causes
- Any type of dysfunction of the patellofemoral joint may cause irritation of the medial synovial plica. This dysfunction can be due to overuse, injury, or abnormal mechanics.
- Patients often have concurrent patellar subluxation or apprehension and this should be assessed as part of the physical examination. In addition, these patients often have a component of tight hamstrings or concurrent irritation of the pes anserine bursa. Measuring the hamstring-popliteal angle assesses hamstring tightness, while direct palpation assesses irritation of the pes anserine bursa.
- Direct blows to the knee can also result in irritation of the medial plica (eg, dashboard injuries, fall on a flexed knee).
- In addition, other pathology in the knee joint, such as a meniscal tear or arthritis, may cause knee effusions or quadriceps atrophy, which could result in plical irritation.
Section 4 of 10
DIFFERENTIALS
Meniscus Injuries
Patellar Injury and Dislocation
Patellofemoral Joint Syndromes
Pes Anserine Bursitis
Other Problems to be Considered
Plica
Osteochondritis dissecans
Medial meniscus tear
Section 5 of 10
WORKUP
Imaging Studies
- Plain radiographs should be ordered in most patients to rule out the differential diagnosis or concurrent possible pathology of a medial synovial plica. Routine radiographs should include a standing anteroposterior (AP), lateral view, and a 45° patellofemoral view. These radiographs help to demonstrate any evidence of medial compartment arthritis, osteochondritis dissecans, or patellofemoral joint pathology.
- An MRI also may be useful to confirm the pressure of a thickened plica (axial view) and to rule out other causes of medial sided knee pain (eg, medial meniscus tear, bone bruise, osteochondritis dissecans).
Procedures
- Diagnostic intra-articular lidocaine injections can be useful in some patients where it is difficult to determine if the pathology is intra-articular or extra-articular. Continued pain after an intra-articular lidocaine injection would point to an extra-articular cause of a patient's pain.
Section 6 of 10
TREATMENT
Acute Phase
Rehabilitation Program
Physical Therapy
The first mode of treatment for suprapatellar plical irritation of the knee is nonoperative. All patients should have a program of physical therapy established for them, which includes closed-chain quadriceps kinetic exercises and a hamstring-stretching program.
An important consideration to recognize is that patients who participate in open-chain quadriceps exercises, especially those that work on knee extension exercises on a weight machine, often have an increase in their suprapatellar plical irritation. A closed-chain quadriceps exercise program should include the use of an exercise bike, leg presses, straight leg raises (with and without leg weights), and the performance of mini-squats or use of a squat rack machine.
Patients should recognize that a hamstring-stretching program must be performed several times daily to maximize their improvement. Approximately 50% of patients notice a significant improvement with an exercise program in the initial 6 weeks, with a larger percentage of the remaining patients improving with an additional 6 weeks of rehabilitation.
Recreational Therapy
Patients who have medial synovial plical irritation should avoid those activities that cause irritation of their knees. This may include avoidance of stairs, squatting activities, or long distance jogging or running until they note improvement with a physical therapy home exercise program.
Medical Issues/Complications
The most common complication associated with medial synovial plical irritation is continued pain or increased pain after surgery. For this reason, it is important to have exhausted all nonoperative forms of treatment for patients prior to any attempts at surgery.
Surgical Intervention
In patients who have exhausted all other means, an arthroscopic evaluation of the knee may be indicated. Since a debrided synovial plica results in alleviation of symptoms in only about 60-70% of cases, with some of the remaining patients actually having more pain after surgery, it is recommended that the synovial plica be debrided only if significant scar tissue is present in the plica or if shelf erosion is noted on the medial femoral condyle from a fibrotic plica.
Consultations
Any patient who fails this treatment protocol should have consultation with a subspecialist fellowship-trained orthopedic surgeon dealing with knee pathology.
Other Treatment
In patients who have continued pain after a rehabilitation or home therapy program, consideration should be given in these patients for a possible combined local anesthetic and corticosteroid injection to try and decrease some of their inflammation.
Patients who undergo this injection need to recognize that they still need to address their underlying quadriceps dysfunction and hamstring tightness. They need to either be enrolled in a physical therapy program or have a well-instituted home therapy program after the injection to maximize their chances for a good outcome.
Maintenance Phase
Rehabilitation Program
Physical Therapy
Once a patient has recovered from their plical irritation, they need to recognize that they are very likely to be at risk for a recurrence of symptoms if they do not participate in a maintenance rehabilitation program. Always recommend to these patients that they try to work on a routine exercise program indefinitely to minimize their chances of recurrence of their knee pain.
Section 7 of 10
MEDICATION
Any of the nonsteroidal anti-inflammatory drugs (NSAIDs) may be used to try to supplement the physical therapy program. Generally, it is recommended to start with over-the-counter (OTC) NSAIDs first. If these do not work, or if they work only in the maximum doses, prescription drugs may be utilized based upon the patient's previous success with these medications, drug allergies, or other medications.
Drug Category: Nonsteroidal anti-inflammatory agents
Have analgesic, anti-inflammatory, and antipyretic activities. Their mechanism of action is not known, but may inhibit cyclo-oxygenase activity and prostaglandin synthesis. Other mechanisms may exist as well, such as inhibition of leukotriene synthesis, lysosomal enzyme release, lipoxygenase activity, neutrophil aggregation, and various cell membrane functions.
|
Drug Name |
Ibuprofen (Motrin, Ibuprin) |
|
Description |
An OTC NSAID useful to decrease pain and inflammation. DOC for patients with mild to moderate pain. Inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis. |
|
Adult Dose |
200-800 mg PO tid |
|
Pediatric Dose |
Not established |
|
Contraindications |
Documented hypersensitivity; peptic ulcer disease, recent GI bleeding or perforation, renal insufficiency, or high risk of bleeding |
|
Interactions |
Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and, possibly, toxicity of NSAIDs; may decrease effect of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; monitor PT closely (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently |
|
Pregnancy |
B - Usually safe but benefits must outweigh the risks. |
|
Precautions |
Category D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy |
Section 8 of 10
FOLLOW-UP
Return to Play
Patients/athletes may return back to participation in sports based upon their symptoms. Athletes are recommended to start out slowly and observe how their knee reacts overnight, prior to advancing their workout/exercise regimen. This gradual progression is important to follow because plical irritation appears to involve some tissue inflammation, which may take some patients hours to develop after activities. Usually, it is safe to say that if a patient does not have pain or swelling with an activity, that it is safe to continue or attempt to advance in that activity.
Complications
Nonoperative complications include continued medial synovial plical irritation, which over time could potentially lead to a fibrotic plica. The most common complication, which is more a poor result than a complication, is increased pain after surgical debridement due to increased scar tissue formation after surgery. The best way to avoid these complications is to make sure that the patient is enrolled in an appropriate physical therapy or home exercise program.
Prevention
The best way to prevent continued medial synovial plical irritation is to avoid those activities that cause irritation and to address the problem that caused the plical irritation in the first place. This would include surgery to address meniscal tears or cartilage flaps or enrollment in a proper physical therapy program for those with patellofemoral dysfunction.
Prognosis
The overall prognosis for most patients with medial synovial plical irritation is good. Most patients will respond to a physical therapy program within the first 6-8 weeks, with most of the other patients responding over the next few months. Surgical intervention for a medial synovial plica should be reserved for those patients who have failed all other modalities previously described in this article.
Education
Most patients need to be instructed in a home exercise program to address their underlying quadriceps weakness and hamstring tightness. In addition, many of these patients may have a recurrence of some symptoms over time. Patients need to be informed of this possibility and be instructed to work on a home exercise program first before consulting their physician's office because they frequently can have an alleviation of symptoms with this program.
Section 9 of 10
MULTIMEDIA
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Section 10 of 10
REFERENCES
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- Broom MJ, Fulkerson JP. The plica syndrome: a new perspective. Orthop Clin North Am. Apr 1986;17(2):279-81. [Medline].
- Dorchak JD, Barrack RL, Kneisl JS, Alexander AH. Arthroscopic treatment of symptomatic synovial plica of the knee. Long-term followup. Am J Sports Med. Sep-Oct 1991;19(5):503-7. [Medline].
- Hardaker WT, Whipple TL, Bassett FH 3rd. Diagnosis and treatment of the plica syndrome of the knee. J Bone Joint Surg Am. Mar 1980;62(2):221-5. [Medline].
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- Patel D. Plica as a cause of anterior knee pain. Orthop Clin North Am. Apr 1986;17(2):273-7. [Medline].
- Rovere GD, Adair DM. Medial synovial shelf plica syndrome. Treatment by intraplical steroid injection. Am J Sports Med. Nov-Dec 1985;13(6):382-6. [Medline].
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