An Introduction to the Plica

Transcription

1 /82/ $02.00/0 THE JOURNAL OF ORTHOPAEDIC AND SPORTS PHYSICAL THERAPY Copyright O 1982 by The Orthopaedic and Sports Physical Therapy Sections of the American Physical Therapy Association An Introduction to the Plica T. A. BLACKBURN, JR., MS, PT, ATC,* W. GORDON EILAND, PT,? WILLIAM D. BANDY, PTt Physical therapy literature has been void of information concerning the plica. The authors discuss the literature available past and present. Using current published information and clinical experience, the authors have described the functional anatomy, the evaluation, the surgery, and the prevention and postoperative rehabilitation programs. Case studies were used to demonstrate conservative and nonconservative approaches in treating the plica syndrome. A plica is a distinct, permanent fold of the synovium of the knee which is present in 20-60% of the population (depending on the author). If injured, the plica may become pathological and play a role in various injuries of the knee. Physical therapy literature has given brief reference to the plica as being a possible consideration in knee pathology. However, little anatomical background, evaluation procedures, or specific treatme'nt protocols have been included. (This condition has been referred to by various authors as plica synovialis, medial shelf syndrome, suprapatellar plica synovitis, and medial plica synovitis. For the sake of simplicity, this condition will be called the plica syndrome.) The purpose of this paper is to review the anatomical structure of the plica, describe its function in the knee, and show how pathology of this structure can cause severe knee problems. Emphasis will be put on evaluation, treatment, surgical indications, and postsurgical rehabilitation. suprapatella plica in internal derangement of the knee in With the beginning of the 1970s and the increased use of and expertise with the arthroscope, numerous articles appeared concerning this subject. Hughston and Andrews7 described the suprapatellar plica and its role in internal derangement of the knee at the American Academy of Orthopaedic Surgeons in 1973; Pateli2 described arthroscopy and the synovial plica in 1978, followed in 1980 by Hardacker3 with an article concerning the diagnosis and treatment of the plica. ANATOMY The above authors all come to the conclusion that the synovial fold forms embryologically. At this time, the medial and lateral compartments, as well as the suprapatellar pouch, are divided by thin membranes. These three synovial cavities fuse into a single chamber at about the fourth month of intrauterine life and there is absorption of intervening synovial ti~sue.~~~~'~~'~ In 20-60%i.9.ii.i7 of all adult knees, remnants REVIEW OF LITERATURE of this synovial tissue still exist, resulting from incomplete absorption. The remaining fold of the Reference to the synovial plica in the literature synovium is what has become known as the prior to 1970 is relatively scarce. Two Japanese plica. surgeons, Linog (1939) and Mizumachi" (1948), Researchers differ on the exact make-up of described arthroscopic findings in adult cadav- the plica. Hughston and ~ndrews~ report that it ers including the plica and reported the so-called is one sweeping structure that begins dorsal to synovial shelf syndrome. Lesions of the supra- the vastus lateralis area of the quadriceps tendon patellar plica were described by Pipkini3 in and extends transversely and medially to the 1950, and Hughston6 reported the role of the medial wall of the knee joint where it courses distally, obliquely inserting on the synovium covering the infrapatellar fat pad. Athroscopists de- ' Chief of Sports Physical Therapy at Rehabilitation Services of scribe three distinct plica: 1) that portion that Columbus. Inc.. Columbus. GA t From Western Reserve Therapists, Inc.. Chesterland. OH Courses from the lateral patellar tendon to the 171

2 172 BLACKBURN ET AL JOSPT Vol. 3, No. 4 medial wall of the knee joint (the suprapatellar able to pass back and forth over the femoral plica), 2) that portion that runs along the medial condyles in flexion and extension without prowall to the infrapatellar fat pad (the medial pa- ducing abnormal forces on the articular cartitellar plica), and 3) the section running parallel lage. Injury to this structure may occur from a to the anterior cruciate ligament (the infrapatellar direct blow to any portion of the plica, stretching plica, also called the ligamentum muc~sa).~.'~~'~ or tearing of the plica caused by a twisting mo- Hughston and Andrews8 feel that functionally the tion producing a valgus or anteromedial rotary plica can be described as one structure. (See force, or in some cases, repeated high levels of Figure 1.) acti~ity.~"~' l6 Weakness or inappropriate activity PATHOPHYSIOLOGY The presence of the plica in a knee does not in itself constitute a pathological condition. It only adds one more possible source of injury in the already vulnerable knee joint. The normal plica is a soft pliant tissue, highly elastic and in the vastus medialis obliques may also cause irritation.' The changes resulting from these injuries are inflammatory with resulting edema and thickening. Continued trauma will cause progression to a tough, inelastic fibrotic band. (Some authors even report hyalinization and calcification in advanced case^.)^^'^^'^^'^ (See Figure 2, clinical picture of plica surgery.) Fig. 1. A: Plica from the medial to lateral view on a right knee; 6: Plica from the anterior to posterior view on a right knee.

3 JOSPT Spring 1982 The plica is stretched in a bowstring fashion across the medial femoral condyle underneath the patella. This condition may lead to chondromalacia of the patella and/or the medial femoral ~ ondyle,~~'~~'~*'~~ j6 quadriceps atrophy, and hamstring tightness. This pathological plica may be present alone or associated with other pathological entities of similar etiology such as meniscus tears, synovitis, Osgood-Schlatter disease, loose bodies, or osteochondritis dissecans.3, 14'16 EVALUATION History The patient may report an episode of blunt trauma, twisting injury, or repeated minor traumas (such as increased athletic activity) followed by swelling and a dull aching pain along the medial patella. A classic symptom is the inability to sit for any length of time with the knee flexed. These individuals find it necessary to sit in aisle seats at the movies with their knee extended, move their car seat back, etc. This pain results from the plica being drawn tightly over the femoral condyle and pressed under the patella during flexion. Pain is generally increased with activities requiring flexion of the knee while supporting body weight or applying pressure, as in stair climbing or resistive extension exercises. Fig. 2. Plica as seen at surgery. The patient may also report episodes of snapping, clicking, or giving way. Palpation The plica can normally be palpated just medial to the superior border of the patella (Fig. 3). Clinical Signs Stutter Test. The Stutter Test as described by Pipkin is as follows: "Seat the subject on the edge of the examining table with both legs dangling. Place one finger on the patella and ask the patient to extend his knee. Somewhere in the arc between 60' and 45' flexion, the patella 'stutters' in an otherwise smooth recovery. After this 'jump,' which may be sufficient to throw the examiners' fingers off the patella, the patella resumes its smooth course into the full extension."'3.14 An objective manifestation of the Stutter Test is currently being studied by Porterfield and Goldbergi5 with extremely promising results. It is the intent of this study to show that the Cybex (Lumex Inc., Bay Shore, NY) can be used in assisting with the assessment of some forms of plica syndrome. This is accomplished by long curve analysis of the quadriceps muscle showing a biomechanical deviation of the quadriceps

4 BLACKBURN ET AL JOSPT Vol. 3. No. 4 Fig. 4. Straight leg raise. Fig. 3. Palpations of the plica. curve at 30' per second lever arm speed. (See "Case Study 2.") Medial Compression Test. Pain on moving the patella medially with the knee passively flexed to 30" by examiner will cause pain. (This pinches the edge of the plica between the medial femoral condyle and the patella displaced medially by the e~aminer.)'~.'~ McMurray's Test (False Positive). The click in the medial McMurray's test will be under the patella and not at the joint ~pace.'~~'~this due to external rotation of the tibia causing the plica to be more tightly wedged between the medial facet of the patella and the medial femoral condyle. Variations in the manifestations of these clinical signs will vary with the stage of injury. In the acute phase, painful palpation may be the prominent sign, while in the chronic phase, when fibrosis has set in, the Stutter Test and Mc- Murray's Test will be positive. CONSERVATIVE TREATMENT Conservative treatment can be successful in the management of the plica syndrome, especially in the acute phase with symptoms of short duration. (A conservative approach is aimed at reduction of inflammation, quadriceps strengthening, and hamstring stretching to relieve symptoms and discourage fibrosis from repeated minor traumas.) Quadriceps Strengthening Quadriceps strengthening is important to prevent atrophy associated with knee injury and biasing the quadriceps to draw the plica upward and prevent impingement between the patella and femoral condyles. The primary mechanism for this action is through the articularis genus muscle, which is an offshoot of the vastus intermedius and inserts on the upper and posterior aspect of the synovial membrane of the knee joint. The articularis genus has the same innervation as the vastus intermediu~.~.'~ Quadriceps Setting At least 50 quad sets per waking hour are performed holding for a 6-second count. Straight Leg Raising Straight leg raises are done in the supine position with the opposite knee bent to protect the back. The patient will work up to eight sets of 10 repetitions, at least twice a day, with no resistance at the ankle and then gradually increasing the resistance up to 10 pounds (Fig. 4). When the patient has progressed beyond the acute phase and symptoms are subsiding, progressive resistive exercises in limited range may be initiated. These should start with limited flexion, above that point in the range where the patient experiences pain. As the patient's painfree range increases, so can range through which the progressive resistive exercises can be accomplished. Hamstring Stretching This is important to prevent the compressive forces of the patella against the femoral condyles, thus pinching the plica, which can occur when the quadriceps must work against a shortened hamstring. Stretching is done in a static mode usually with the patient sitting or standing and leaning forward at the hips, holding for a period of 1-2 minutes (Fig. 5). It is recommended the exercises be done three times a day.

5 JOSPT Spring 1982 A Fig. 5. A: Hamstring stretching-standing; stretching-supine. a -- 6: Hamstring Aspirin (or other antiinflammatory medication) and ice are also recommended to help decrease inflammation and effusion. Contraindications Exercises done through the full range of knee motion are contraindicated as this irritates the plica. If the plica is acute, bicycling should also be avoided, as well as running or stair climbing. Squats are also contraindicated. SURGERY If the patients' symptoms do not subside after a 6- to 8-week course of conservative treatment, then surgery may be indicated. In this case, the patients are still having a good deal of pain and their symptoms persist enough to hinder them in their daily activities and sporting events. The rehabilitation postoperatively will vary with the complicating lesions. Following an open arthrotomy and excision of the plica, the patient will be immobilized for 2-3 days at which pointactive range of motion exercises are begun to gain flexion. Quad setting and straight leg raising are done minimally during the first week to 10 days so as not to irritate the synovium. Gait is weight bearing to tolerance with crutches. Ninety degrees of knee flexion is usually obtained in 5-7 days after surgery. The patient will go home working on his range of motion and begin to increase his straight leg raising activity. Care must be taken to make sure the quadricep is contracting in an isolated fashion to maintain as much active knee extension as possible for proper gait. If the patient allows the knee to buckle forward with gait, the synovium will be irritated. The patient who has the arthroscopic division of the plica will begin motion at the knee immediately. Straight leg raises, quadricep setting, and hamstring stretching are also done immediately with slow progression up to eight sets of 10 repetitions three times a day. Full knee flexion is expected within days. Care must be taken not to irritate the synovial lining of the postoperative knee. The patient must refrain from running, bent to straight knee exercises, and excessive stair climbing. A gradual return to bicycling is encouraged with the seat high for minimal flexion. Swimming is very beneficial. Once full knee extension is obtained and effusion of the knee is decreased, isokinetic exercises at fast speeds can be utilized. As with many knee patients, no running is begun until full range of motion is obtained with no joint effusion or pain, and the quadricep on the injured side should be approaching the strength of the opposite quadricep. CASE STUDY 1 A 16-year-old heavyweight wrestler was first seen on February 4,1981, because of knee pain not allowing him to fully flex or extend. The patient reported that pain began after a direct fall on the knee during wrestling practice the previous day. The patient was able to continue wrestling for the duration of practice and reported the injury the next day. Evaluation revealed slight knee effusion, pain upon palpation of the plica only, and elevated local temperature. Structural examinations revealed no laxity, and no meniscal involvement was evident. The patient was assessed as having plica syndrome, conservative treatment as previously outlined was initiated immediately, and he was not allowed to practice. After 3 days, the patient was able to compete in a wrestling tournament with no return of pain and placed second.

6 BLACKBURN ET AL JOSPT Vol. 3, No. 4 A 32-year-old white male was initially seen with the chief complaint of gradual onset of pain in his right knee over approximately 1 % years. It had begun getting progressively worse and was proportional to activity, such as running and jumping. The site of pain was subpatellar and was described as being sharp and stabbing. The patient also reported a sensation of his right knee giving way, which decreased his athletic function. The first Cybex evaluation on April 30, 1980, revealed a significant, consistant, biomechanical deviation of the quadricep curve at 30' per second lever arm speed (Fig. 6A). The patient experienced pain coinciding with the range of motion of the deviation. At this time, he was placed on a rehabilitation program consisting of isotonic strengthening exercises above and below the painful range of motion. Cybex evaluation 2 (Fig. 6B), dated May 30, 1980, revealed a 15% increase in work done, but the biomechanical deviation persisted. The TORQUE FT -LBSI POSITION ANGLE (DEG 1 I physician was then contacted concerning this finding, and arthroscopic resection of a plica was performed. Cybex evaluation 3 on August 18, 1980, which was after surgery, revealed a weakness of the quadriceps mechanism, but a definite change in the biomechanics of the torque curve (Fig. 6C). (Figure 6D shows the normal opposite quadricep and hamstring strengths.) The patient is now back to unlimited activity, including running. SUMMARY The physical therapist should be aware that the plica is a distinct structure of the knee and has pathologies that must be treated. The high rate of success with early conservative treatment makes it a problem physical therapists should have the knowledge to assess and treat accordingly. In addition, the physical therapist can be involved with postoperative rehabilitation when conservative treatment fails and surgery is necessary. It is also important that the physical Fig. 6. A: Preoperative Cybex evaluation before exercise programs at paper scale of 360 foot-pounds; 6: Preoperation Cybex evaluation after 1 month of exercises at paper scale of 180 foot-pounds; C: Postoperative Cybex evaluation after 2 months at paper scale of 360 foot-pounds; D: Postoperative Cybex evaluation of the opposite leg after 2 months at paper scale of 360 foot-pounds.

7 JOSPT Spring therapist be aware of the plica and the complications it can present when dealing with other knee problems. The authors would like to thank Emily Craig, MS, of the Hughston Orthopaedic Clinic for pictures and drawings; Michelle Eiland for typing; and James A. Porterfield. MA. PT, ATC, and Dave Goldberg, PT, of the Akron City Hospital Physical Fitness Center for Cybex information. REFERENCES 1. Akoi, T: The ledge lesion in the knee. In: Proceeding of the Twelfth Congress of the International Society of Orthopaedic Surgery and Traumatology, P 462. Amsterdam: Excerpta Howmedica Beck J (personal communication), Hardaker WT, Whatley, GS, Basset FH: Diagnos~s and treatment of the plica syndrome of the knee. J Bone Joint Surg 62A: Hettinga DL: I. Normal joint structures and their reaction to injury. J Orthop Sports Phys Ther 1 : Hoppenfeld, WH: Textbook of Anatomy, Ed 2. New York: Harper & Row, Publishers, Hughston JC: The role of the suprapatellar plica in internal derangement of the knee. Am J Orthop 5:25-27, Hughston, JC, Andrews JR: The suprapatellar plica and internal derangement. Proceedings of the American Academy of Orthopaedic Surgeons. J Bone Joint Surg 55A:1318, Hughston JC. Andrews JR, Columbus. GA (personal communication) 9. Lino S: Normal arthroscopic findings in the knee joint in adult cadavers. J Jpn Orthop Assoc 14: , Mital M, Hayden J: Pain in the knee in children: the medial plica shelf syndrome. Orthop Clin North Am 10: Mizumachi S, Kawashima W, Okamura T: So-called synovial shelf in the knee joint. J Jpn Orthop Assoc 23: Patel D: Arthroscopy of the plicae-synovial folds and their significance. Am J Sports Med , Pipkin G: Lesions of the suprapatellar plica. J Bone Joint Surg 32: Pipkin G: Knee injuries: the role of the suprapatellar plica and suprapatellar bursa in stimulating internal derangements. Clin Orthop 14: Porterfield J, Goldberg D, Akron City Hospital, Akron. OH (personal communication) 16. Reid GD, Glascow M, Gordon D. Wright TA: Pathological plicae of the knee mistaken for arthritis. J Rheumatol7: , Sakakibara J: Arthroscopic study of linos band (plica synovialis mediopatellaris). J Jpn Orthop Assoc 50: