Lateral A
case
synovial plica syndrome
report
MASAHIRO KUROSAKA,* MD, SHINICHI YOSHIYA, MD, MASAHIRO YAMADA, MD, AND KAZUSHI HIROHATA, MD From the
Department of Orthopaedic Surgery, Kobe University, Kobe, Japan the synovial membrane at the lateral aspect of the patella in both knees. A diagnosis of bilateral lateral plica syndrome was made and arthroscopic examination was performed under lumbar anesthesia. At surgery, the only abnormality related to the lateral patellofemoral compartment was a yellowish-white, tongue-shaped band of tissue extending transversely from the lateral parapatellar synovium to cover a part of the lateral face of the patella (Fig. lA). Parts of this tissue mass were hemorrhagic. After drainage of the knee, we observed that this band of tissue impinged in the lateral patellofemoral joint on pressure applied to the lateral aspect of the patella, and when the knee joint was flexed and extended. The site of impingement corresponded to the site of hemorrhage (Fig. 1B). The findings were strikingly similar in both knees. On confirmation of the bilateral lateral synovial plica syndrome, the abnormal tissue was resected from both knees with arthroscopic power instruments. After resection, each kllf’e was drained and examined. Impingement no longer occurred. Examination of the resected synovial tissue revealed a proliferation of capillaries and fibrosis of subsynovial tissue, accompanied by a mild proliferation of the synovial lining cells and infiltration by inflammatory cells. After surgery, the painful clicking disappeared from the left knee but persisted on the right side. Repeat arthroscopy was undertaken 2 weeks later, this time under local anesthesia. Arthroscopic examination did not show impingement or snapping during passive motion or with pressure applied to the patella. However, on active contraction of the quadriceps, snapping occurred again. The snapping this time was located in the lateral aspect of the parapatellar synovial tissue. We therefore undertook further resection. Pain was alleviated and the snapping disappeared after this procedure. At 21/2-year followup, the patient was able to participate in unlimited activities without pain.
Plicae of the synovial membrane can be a cause of dynamic derangements of the patellofemoral joint. The anatomic
significance of the medial plica and the associated clinical syndromes have already been well documented in the literature.3,4.6-8 However, there have been very few reports of problems caused by lateral synovial plica. We encountered a case in which bilateral knee pain and snapping were produced by impingement of lateral synovial plicae. Arthroscopic removal of the plica was performed with good results. The anatomical significance and clinical implications of lateral synovial plica are discussed. CASE REPORT A 21-year-old volleyball player first noticed pain in both knees during participation in high school sports. Pain was episodic but progressive, frequently associated with a painful click. There had been no history of trauma or any other inciting factor. On initial presentation, little abnormality of either knee was detected. The patient was placed on a conservative exercise program that included quadriceps exercises. However, his symptoms failed to improve. The pain and snapping of the patellae worsened gradually and became noticeable even during walking. On examination, a cordlike painful thickening was palpable at the lateral side of each patella. The thickening could be accentuated by pushing the patella laterally. During active knee motion, palpable snapping was observed at the lateral aspect of the patella with the joint flexed at an angle of about 20°. No snapping was produced with passive knee motion. No swelling, redness, local heat, or effusion was observed, and knee motion was unrestricted. Examination of the menisci was negative and no apprehension was found. Plain radiographs were normal, but arthrography suggested possible abnormal thickening of
DISCUSSION *
Address correspondence and reprint requests to: Masahiro Kurosaka, MD, Department of Orthopaedic Surgery, Kobe University School of Medicine, 75-1, Kusunoki-cho, Chuo-ku, Kobe, Japan.
In the normal knee joint, soft tissue structures located distal patella include the infrapatellar synovial plica, which
to the 92
93
Figure 2. Anatomic structures around the patella (P).
1. A, lateral plica showing hermorrhage. B, impingement in the patellofemoral joint when pressure was applied
Figure on
the
patella. P, patella; FC, femoral condyle.
through the intercondylar notch; the plicae alares, which extend proximally along the medial and lateral margins of the patella; and the infrapatellar fat pad. Proximal to the patella is the suprapatellar synovial plica, which forms an incomplete septum with the suprapatellar pouch. A narrow strip of adipososynovial tissue, which was referred to as the parapatellar adipososynovial fringe, is found on the sides of the patella (Fig. 2). In addition to these anatomic plicae, certain abnormal synovial plicae may also be observed, and these may produce passes
symptoms. Most
common
among these is the medial shelf
medial synovial plica.3-8 There has been little literature describing anatomic lesions of the lateral synovial plica.’ The few clinical reports of knee disorders caused by a lateral synovial plica have been mainly in the Japanese literature,1,2,5 with the first
syndrome produced by the
report of five cases by Kurosawa et al.5 As with the medial plica syndrome, most cases involved young patients. We could find only two cases of lateral synovial plica syndrome reported in the English literature.’ As to the location and clinical significance of the lateral synovial plica, Kurosawa’ described the plica as a slightly wider and thicker band than is usually found medially. It is often found as an irregular, bandlike mass of tissue extended in parts to form one-tongue or two-tongue masses. These extend along the lateral margin of the patella. The medial surface is relatively blunt. Inferiorly, the extended plica connects with the infrapatellar fat pad, whereas superiorly it is gradually replaced by normal synovial tissue (Fig. 3). In our case, the lateral synovial plica was short and thick; it was located immediately lateral to the patella, covering a portion of the lateral facet. Therefore, this form corresponded well with the descriptions given by Kurosawa et al.5 Embryologically, the medial synovial plica is believed to be a vestige of a septum that separates the joint space. Judging from the structure and form of the plica, we believe that the lateral synovial plica is not a vestigial septum but is derived from the lateral parapatellar adipososynovial fringe that is normally found (Fig. 2). Since the injury in our case was remarkably symmetric, we believe that the problems arose in each knee from some congenital hypertro-
94
action. This may explain why, in our case, the snapping was not found preoperatively with passive motion, but was found with active quadriceps contraction. Furthermore, the absence of impingement in the patellofemoral joint after arthroscopic removal of the plica under lumbar anesthesia did not account for the role of muscle action. Even after the patient was released from spinal anesthesia, the snapping persisted in the right side. The snapping was reaffirmed under local anesthesia with quadriceps contraction and relieved by further resection of plica. In clinical situations in which symptoms are provoked by active contraction of the quadriceps, arthroscopy should be performed under local anesthesia so that the evaluation may be undertaken in a situation that can best approximate the conditions producing the problem.
CONCLUSIONS Our
provides an example of internal knee derangement a lateral synovial plica. It was likely that the problem was induced from a developmental hypertrophy of the lateral parapatellar structures, since it occurred bilaterally and symmetrically. The lack of previous documentation of this problem in the English literature shows that it is a relative rarity and therefore difficult to diagnose precisely. Our experience offers guidance with respect to assessment and arthroscopic treatment of this problem. We thank T. Derek V. Cooke, FRCS, for his helpful suggestions and discussion in preparing this manuscript. case
caused by
REFERENCES
Regan BF: Medial and lateral synovial plicae of the knee: Pathological significance, diagnosis and treatment by arthroscopic surgery.
1. Bough BW,
Figure 3.
Schema of the lateral synovial plica. Irregular bandlike mass of tissue extends along the lateral margin of the
patella (P; arrow). PAF, para patellar adipososynovial fringe; IPF, infrapatellar fat pad.
phy of the lateral parapatellar adipososynovial fringe. It may be that this hypertrophic fringe tissue impinged in the patellofemoral joint during active motion, resulting in repetitive chronic mechanical irritation. Subsequent inflammatory reactions and fibrosis may then have lead to the thick bandlike plica manifesting the clinical symptoms. The shape of synovial plica changes with distension of the joint cavity and also with active motion caused by muscle
2.
Irish Med J 78: 279-282, 1985 Fujisawa Y, Matsumoto N, Shiomi S, et al: Problems caused by the medial and lateral synovial folds of the patella (in Japanese). Kansetsukyo 1: 40-
44, 1976 3. Hardaker WT, Whipple TL, Bassett FH: Diagnosis and treatment of the plica syndrome of the knee. J Bone Joint Surg 62A: 221-225, 1980 4. Ino S: Normal arthroscopic findings in the knee joint in adult cadavers. J
Jpn Orthop Assoc 14: 467-518, 1939 5. Kurosawa S, Koide S, Yaota T, et al: Disorders of the knee caused by synovial plicae: So-called plica syndrome. Clin Orthop Surg 11: 231-237, 1979 6. Mizumachi S, Kawashima W, Okamura T: So-called synovial shelf in the knee joint. J Jpn Orthop Assoc 23: 22-25, 1948 7. Patel D: Arthroscopy of the plica-synovial folds and their significance. Am J Sports Med 6: 217-225, 1978 8. Sakakibara J: Arthroscopic study on Ino’s band (plica synovialis mediopatellaris). J Jpn Orthop Assoc 50: 513-522, 1976
case
synovial plica syndrome
report
MASAHIRO KUROSAKA,* MD, SHINICHI YOSHIYA, MD, MASAHIRO YAMADA, MD, AND KAZUSHI HIROHATA, MD From the
Department of Orthopaedic Surgery, Kobe University, Kobe, Japan the synovial membrane at the lateral aspect of the patella in both knees. A diagnosis of bilateral lateral plica syndrome was made and arthroscopic examination was performed under lumbar anesthesia. At surgery, the only abnormality related to the lateral patellofemoral compartment was a yellowish-white, tongue-shaped band of tissue extending transversely from the lateral parapatellar synovium to cover a part of the lateral face of the patella (Fig. lA). Parts of this tissue mass were hemorrhagic. After drainage of the knee, we observed that this band of tissue impinged in the lateral patellofemoral joint on pressure applied to the lateral aspect of the patella, and when the knee joint was flexed and extended. The site of impingement corresponded to the site of hemorrhage (Fig. 1B). The findings were strikingly similar in both knees. On confirmation of the bilateral lateral synovial plica syndrome, the abnormal tissue was resected from both knees with arthroscopic power instruments. After resection, each kllf’e was drained and examined. Impingement no longer occurred. Examination of the resected synovial tissue revealed a proliferation of capillaries and fibrosis of subsynovial tissue, accompanied by a mild proliferation of the synovial lining cells and infiltration by inflammatory cells. After surgery, the painful clicking disappeared from the left knee but persisted on the right side. Repeat arthroscopy was undertaken 2 weeks later, this time under local anesthesia. Arthroscopic examination did not show impingement or snapping during passive motion or with pressure applied to the patella. However, on active contraction of the quadriceps, snapping occurred again. The snapping this time was located in the lateral aspect of the parapatellar synovial tissue. We therefore undertook further resection. Pain was alleviated and the snapping disappeared after this procedure. At 21/2-year followup, the patient was able to participate in unlimited activities without pain.
Plicae of the synovial membrane can be a cause of dynamic derangements of the patellofemoral joint. The anatomic
significance of the medial plica and the associated clinical syndromes have already been well documented in the literature.3,4.6-8 However, there have been very few reports of problems caused by lateral synovial plica. We encountered a case in which bilateral knee pain and snapping were produced by impingement of lateral synovial plicae. Arthroscopic removal of the plica was performed with good results. The anatomical significance and clinical implications of lateral synovial plica are discussed. CASE REPORT A 21-year-old volleyball player first noticed pain in both knees during participation in high school sports. Pain was episodic but progressive, frequently associated with a painful click. There had been no history of trauma or any other inciting factor. On initial presentation, little abnormality of either knee was detected. The patient was placed on a conservative exercise program that included quadriceps exercises. However, his symptoms failed to improve. The pain and snapping of the patellae worsened gradually and became noticeable even during walking. On examination, a cordlike painful thickening was palpable at the lateral side of each patella. The thickening could be accentuated by pushing the patella laterally. During active knee motion, palpable snapping was observed at the lateral aspect of the patella with the joint flexed at an angle of about 20°. No snapping was produced with passive knee motion. No swelling, redness, local heat, or effusion was observed, and knee motion was unrestricted. Examination of the menisci was negative and no apprehension was found. Plain radiographs were normal, but arthrography suggested possible abnormal thickening of
DISCUSSION *
Address correspondence and reprint requests to: Masahiro Kurosaka, MD, Department of Orthopaedic Surgery, Kobe University School of Medicine, 75-1, Kusunoki-cho, Chuo-ku, Kobe, Japan.
In the normal knee joint, soft tissue structures located distal patella include the infrapatellar synovial plica, which
to the 92
93
Figure 2. Anatomic structures around the patella (P).
1. A, lateral plica showing hermorrhage. B, impingement in the patellofemoral joint when pressure was applied
Figure on
the
patella. P, patella; FC, femoral condyle.
through the intercondylar notch; the plicae alares, which extend proximally along the medial and lateral margins of the patella; and the infrapatellar fat pad. Proximal to the patella is the suprapatellar synovial plica, which forms an incomplete septum with the suprapatellar pouch. A narrow strip of adipososynovial tissue, which was referred to as the parapatellar adipososynovial fringe, is found on the sides of the patella (Fig. 2). In addition to these anatomic plicae, certain abnormal synovial plicae may also be observed, and these may produce passes
symptoms. Most
common
among these is the medial shelf
medial synovial plica.3-8 There has been little literature describing anatomic lesions of the lateral synovial plica.’ The few clinical reports of knee disorders caused by a lateral synovial plica have been mainly in the Japanese literature,1,2,5 with the first
syndrome produced by the
report of five cases by Kurosawa et al.5 As with the medial plica syndrome, most cases involved young patients. We could find only two cases of lateral synovial plica syndrome reported in the English literature.’ As to the location and clinical significance of the lateral synovial plica, Kurosawa’ described the plica as a slightly wider and thicker band than is usually found medially. It is often found as an irregular, bandlike mass of tissue extended in parts to form one-tongue or two-tongue masses. These extend along the lateral margin of the patella. The medial surface is relatively blunt. Inferiorly, the extended plica connects with the infrapatellar fat pad, whereas superiorly it is gradually replaced by normal synovial tissue (Fig. 3). In our case, the lateral synovial plica was short and thick; it was located immediately lateral to the patella, covering a portion of the lateral facet. Therefore, this form corresponded well with the descriptions given by Kurosawa et al.5 Embryologically, the medial synovial plica is believed to be a vestige of a septum that separates the joint space. Judging from the structure and form of the plica, we believe that the lateral synovial plica is not a vestigial septum but is derived from the lateral parapatellar adipososynovial fringe that is normally found (Fig. 2). Since the injury in our case was remarkably symmetric, we believe that the problems arose in each knee from some congenital hypertro-
94
action. This may explain why, in our case, the snapping was not found preoperatively with passive motion, but was found with active quadriceps contraction. Furthermore, the absence of impingement in the patellofemoral joint after arthroscopic removal of the plica under lumbar anesthesia did not account for the role of muscle action. Even after the patient was released from spinal anesthesia, the snapping persisted in the right side. The snapping was reaffirmed under local anesthesia with quadriceps contraction and relieved by further resection of plica. In clinical situations in which symptoms are provoked by active contraction of the quadriceps, arthroscopy should be performed under local anesthesia so that the evaluation may be undertaken in a situation that can best approximate the conditions producing the problem.
CONCLUSIONS Our
provides an example of internal knee derangement a lateral synovial plica. It was likely that the problem was induced from a developmental hypertrophy of the lateral parapatellar structures, since it occurred bilaterally and symmetrically. The lack of previous documentation of this problem in the English literature shows that it is a relative rarity and therefore difficult to diagnose precisely. Our experience offers guidance with respect to assessment and arthroscopic treatment of this problem. We thank T. Derek V. Cooke, FRCS, for his helpful suggestions and discussion in preparing this manuscript. case
caused by
REFERENCES
Regan BF: Medial and lateral synovial plicae of the knee: Pathological significance, diagnosis and treatment by arthroscopic surgery.
1. Bough BW,
Figure 3.
Schema of the lateral synovial plica. Irregular bandlike mass of tissue extends along the lateral margin of the
patella (P; arrow). PAF, para patellar adipososynovial fringe; IPF, infrapatellar fat pad.
phy of the lateral parapatellar adipososynovial fringe. It may be that this hypertrophic fringe tissue impinged in the patellofemoral joint during active motion, resulting in repetitive chronic mechanical irritation. Subsequent inflammatory reactions and fibrosis may then have lead to the thick bandlike plica manifesting the clinical symptoms. The shape of synovial plica changes with distension of the joint cavity and also with active motion caused by muscle
2.
Irish Med J 78: 279-282, 1985 Fujisawa Y, Matsumoto N, Shiomi S, et al: Problems caused by the medial and lateral synovial folds of the patella (in Japanese). Kansetsukyo 1: 40-
44, 1976 3. Hardaker WT, Whipple TL, Bassett FH: Diagnosis and treatment of the plica syndrome of the knee. J Bone Joint Surg 62A: 221-225, 1980 4. Ino S: Normal arthroscopic findings in the knee joint in adult cadavers. J
Jpn Orthop Assoc 14: 467-518, 1939 5. Kurosawa S, Koide S, Yaota T, et al: Disorders of the knee caused by synovial plicae: So-called plica syndrome. Clin Orthop Surg 11: 231-237, 1979 6. Mizumachi S, Kawashima W, Okamura T: So-called synovial shelf in the knee joint. J Jpn Orthop Assoc 23: 22-25, 1948 7. Patel D: Arthroscopy of the plica-synovial folds and their significance. Am J Sports Med 6: 217-225, 1978 8. Sakakibara J: Arthroscopic study on Ino’s band (plica synovialis mediopatellaris). J Jpn Orthop Assoc 50: 513-522, 1976
