Knee Surgery & Related Research 2018 Dec; 30(4): 356-363
Arthroscopic Excision of Medial Knee Plica: A Meta-Analysis of Outcomes
Adam Daniel Gerrard1, and Charalambos P. Charalambous1,2
1Department of Orthopaedics, Blackpool Victoria Hospital, Blackpool, UK, 2School of Medicine, University of Central Lancashire, Preston, UK
Correspondence to: Charalambos P. Charalambous, FRCS, Department of Trauma and Orthopaedics, Blackpool Teaching Hospitals NHS Trust, Whinney Heys Rd, Blackpool FY3 8NR, UK, Tel: +44-1253955983, Fax: +44-1253953530, E-mail:
Received: February 13, 2018; Revised: April 19, 2018; Accepted: August 1, 2018; Published online: December 1, 2018.
© Korean Knee Society. All rights reserved.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


A meta-analysis was performed to assess the outcomes following surgical intervention for medial knee plica.

Materials and Methods

A literature search of Medline, EMBASE, CINAHL and Cochrane CENTRAL was performed using relevant key words. The primary outcome was patient-reported postoperative scores of “good” and “excellent”. Meta-analyses were performed using a random effects model.


The literature search identified 731 articles. After removing duplicates and those not meeting the inclusion criteria, 12 articles reporting on a total of 643 knees were included for analysis, and of these, 7 articles including 235 knees were used for meta-analysis. The overall rate of good and excellent outcomes following surgery was estimated at 84.2% (95% confidence interval [CI], 72.8–91.4). In those cases that had non-surgical therapy prior to surgery, the rate of good and excellent outcomes of surgery was estimated at 76.1% (95% CI, 60.1–87).


Arthroscopic surgical management of symptomatic medial knee plica results in favourable outcomes. Our results suggest that arthroscopic surgical excision should be considered as a treatment modality in patients with pathological medial plica disease of the knee either as a first-line treatment or when symptoms have not responded to non-surgical interventions.

Level of Evidence


Keywords: Knee, Plica, Medial, Arthroscopy, Excision

The reported incidence of medial plica of the knee found during arthroscopy varies from 22% to almost 80%1,2). The healthy medial plica has smooth elastic properties and slides freely over the femoral condyle with knee movement. However, a pathological medial plica can develop when inflammation and fibrosis occur. Patients suffer anterior knee pain more often on the medial aspect35). The pain is often made worse through activities involving flexion of the knee and may be associated with symptom of knee clicking or locking6). Often there is a history of injury or reparative sporting activity47).

The diagnosis of symptomatic medial plica is challenging, as the medial plica is a common incidental finding8) and the symptoms experienced by the patient with a pathological medial knee plica are indistinguishable on clinical examination to other pathologies of the knee including torn menisci, inflammation, and osteochondral defects9). Similarly, the management of pathological medial plica is controversial10), with beneficial effects reported for both non-surgical11,12) and surgical treatment13). Non-surgical management uses analgesia and anti-inflammatory medications along with physiotherapy. However, when this has not improved the patient’s symptoms, surgical arthroscopic intervention may be employed. At arthroscopy the pathological medial plica may be excised or divided, with studies advocating complete excision to be a superior treatment7). Surgical intervention is not without its risks as a patient is subject to the inherent dangers of surgery including anaesthetic risks and thromboembolic events, combined with the possibility of the surgery not improving symptoms14) or causing local complications such as haemarthrosis and swelling, increasing the patient’s morbidity1517).

A previous meta-analysis performed for all types of knee plica and including children found arthroscopic resection resulted in patients being asymptomatic in 64% of cases and 26% only experiencing intermittent symptoms18). We hypothesise that within adult patients with only pathological medial plica, arthroscopic excision will yield similar positive postoperative outcomes. This will give surgeons, patients, and health care commissioners information to guide best care.

Materials and Methods

A literature search of MEDLINE (1946 to present), EMBASE (1974 to present), CINAHL (1961 to present), and Cochrane CENTRAL (1988 to present) databases was conducted using any combination of the key words, “plica” and “knee” in December 2016 for articles published in English with no publication year limit.

The study inclusion criteria were as follows: studies including patients over the age of 15 years, published in the English language, reporting cases having arthroscopic intervention in medial plica disease with no other co-existing knee pathology, and reporting outcomes per knee rather than per patient. Studies that reported their outcomes as excellent, good, fair, or poor were included. Randomised control trials and retrospective and prospective study designs were included, with case series of less than ten patients and case reports excluded.

The title and abstract of the articles were reviewed by both authors against the inclusion criteria. Where no decision about inclusion could be made from the publication title and abstract alone, the full texts were reviewed by the first author. The lists of references for all included articles were searched for any further articles for inclusion not identified in the database search.

An electronic standardised proforma for data extraction was created and utilized. The first author performed data collection, and where there was uncertainty, this was checked by the second author. Where articles included other types of pathology or other types of plica, the data for patients with only medial plica were included.

The Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) methodology was used19). The articles were appraised using the methodological index for nonrandomized studies20).

1. Statistical Analysis

The primary outcome was patient-reported postoperative scores of “good” and “excellent”. Meta-analyses were performed using random-effects model20), 95% confidence intervals (CIs) were calculated, and the heterogeneity was assessed using tau2, I2, Q, and p-values. Funnel plots were created, with no formal asymmetrical tests performed. Data were analyzed with CMA ver. 2 (Biostat, Englewood, NJ, USA).


The search of the databases produced 731 results. Duplicated articles were removed, and the remaining articles were assessed. Those of no relevance were eliminated, leaving 41 articles whose full texts were examined (Fig. 1). Twelve articles were identified that reported outcomes of arthroscopic medial plica excision (Table 1). In the study by Yilmaz et al.16), one patient was under the age of 15 years, and the outcomes of that single case were removed from analysis. These studies reported a total of 643 knees which had arthroscopic surgery for symptomatic medial plica. Follow-up ranged between four and 87 months, with the mean age across the studies of between 25 years and 45 years. Six studies were prospective in their design15,16,2124) and six were retrospective17,2529).

In five of these 12 studies, all participants had undergone a course of physiotherapy and conservative management prior to arthroscopic surgery1517,2227). One contained patients whose symptoms persisted despite prior operations21) whilst six did not state what measures had been tried pre-arthroscopic surgical intervention2326,28,29). Of these 12 studies, three reported no complications from arthroscopic management of medial knee plicae25,22,28), two reported cases of effusion within the knee joint postoperatively with all settling without further operative intervention16,17). One study reported four cases of haemarthrosis which required aspiration at one week28). Of these 12 studies, one described their improvement in outcomes in terms of presence or change in symptoms21), one with regards to presence or absence of knee complaints26), one in terms of influence upon daily activities15), and one in terms of satisfaction24). Two studies used mean functional Lysholm scores pre- and postoperatively. Both of these found improvements with surgery. Yilmaz et al.16) reported a mean preoperative scores of 38.5 and a mean postoperative score of 82. Uysal et al.17) reported a mean preoperative scores of 67.19±8.05 and a mean postoperative score of 90.57±9.80. A third study by Guney et al.29) used Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and published mean preoperative and postoperative scores of 1.4±0.7/1.3 (0–3.04) and 0.2±0.5/0 (0–2.42), respectively, again showing an improvement with surgery. In the studies by Maffulli et al.15) and Uysal et al.17), the included cases had undergone a course of phys iotherapy and conservative management prior to arthroscopic surgery.

Seven studies including 235 knees reported their outcomes as either excellent, good, fair, or poor16,22,23,25,2729) and were thus used for meta-analysis (Table 1). Of these, 3 studies reported cases that had undergone a course of physiotherapy and conservative management prior to arthroscopic surgery16,22,27), and a further metaanalysis was performed for these studies in isolation. Meta-analysis of all seven included studies showed that arthroscopic excision of medial knee plica resulted in favorable outcomes in most cases (Fig. 2). An outcome of good or excellent was seen in 84.2% (95% CI, 72.8–91.4) of knees following arthroscopic resection of pathological medial plica (21 knees; heterogeneity: tau2=0.52; I2=64.7%; Q=17; df=6; p=0.009). Funnel plot visual analysis did not show an obvious small study effect. Meta-analysis of the three studies where the participants had non-surgical interventions prior to arthroscopic surgery showed that arthroscopic excision of medial knee plica resulted in favorable outcomes in most cases; an outcome of good or excellent was seen in 76.1% (95% CI, 60.1–87) following arthroscopic resection of pathological medial plica (Fig. 3) (heterogeneity: tau2=0.22; I2=50.2%; Q=4; df=2; p=0.134).

Critical appraisal of the included studies using MINORS criteria20) are summarised in Table 2. A clearly stated aim could be observed in all. Unbiased assessment of outcomes was not seen in any of the studies, as they did not use independent evaluators to assess the postoperative outcomes.


The results of this meta-analysis demonstrate that arthroscopic excision of symptomatic medial knee plica leads to favourable clinical outcomes in most cases. Hence, based on our results, we recommend that arthroscopic excision of symptomatic medial knee plica is considered as a treatment modality in those patients that fail initial non-surgical management. Five of our included studies looked at patients who had a course of physiotherapy and conservative management prior to arthroscopic surgery. One of these15) showed that 67 of 102 cases had no post-surgery complaints with regards to functional activities, whilst another study17) reported an improvement in the mean Lysholm knee score from 67.19±8.05 prior to surgery to 90.57±9.80 postsurgery. Meta-analysis of three further studies which reported their outcomes as excellent, good, fair, or poor showed that arthroscopic excision of medial knee plica resulted in a good or excellent outcome in an estimated 76.1% (95% CI, 60.1–87) of cases.

Synovial plica of the knee was first described by Mayeda in 1918. It is thought that a plica is a remnant strand of mesenchymal tissue persisting from the embryonic development of the knee cavity between 8–12 weeks of gestation. The medial plica arises from the genu-articularis muscle proximally and passes over the medial femoral condyle to merge with the synovial lining of the joint capsule. It ranges from a cord-like appearance to that of a larger shelf structure30).

The majority of medial knee plica identified during arthroscopy are thin and asymptomatic. However, incidents of trauma or overuse result in plica becoming oedematous and fibrotic, and overtime they may tighten or bowstring4). The usual gliding effect of the medial plica over the femoral condyle between 30° and 60° of flexion is lost, and instead the plica may impinge and cause chondral injuries, resulting in pain, mechanical or other symptoms (swelling, snapping sensation, tenderness, stiffness, and locking)5). Examination of the knee may elicit an effusion, decreased range of motion, tenderness over the medial femoral condyle or joint line and on occasion synovial thickening6).

The arthroscopic surgical management for pathological plica is to either excise or divide the plica. Excision may involve the use of punch, shaver, diathermy or scissor devices to take the plica back to a level where it no longer impinges. Division of the plica is performed by breaking its continuity. Patients in whom the plica is divided may risk the two cut ends re-joining via scar tissue and a return of their symptoms; for this reason excision of the plica has been suggested to be preferential22).

Unfortunately, only three studies16,17,29) reported functional score outcomes. However, although there were not enough studies using the same scoring systems to extract any combined data for analysis, all of the studies reported a mean improvement in their patients who had arthroscopic intervention.

There are a number of limitations to this study. Firstly, the preoperative management of the patients within the different studies was not uniformly described. Some patients had undergone pharmaceutical management and physiotherapy to help their symptoms prior to proceeding with surgery, but it could not be determined as to whether this altered their final surgical outcomes. Patients in studies who specified preoperative conservative management had a benefit to arthroscopic resection in 76%, compared with the 84% who had a positive response when all studies were included. Secondly, there was variation in the outcome evaluation systems employed across studies and therefore only seven could be included in the meta-analysis. Furthermore, outcomes employed were mainly categorical rather than continuous numerical. In addition, most studies were observational, with no randomised trial available comparing surgical versus non-surgical intervention. Most of the studies were produced over 20 years ago with few recent studies available to be used in the analysis.

Despite the above limitations, our meta-analysis brings together clinical outcomes from a large number of pooled cases, from which meaningful conclusions can be reached.


Given the available evidence, our results suggest that arthroscopic excision of symptomatic medial knee plica is associated with favourable patient outcomes in an estimated 76% of those cases that had non-surgical therapy prior to surgery and 84% of all patients included. Based on these findings, we recommend that arthroscopic surgical excision should be considered as a treatment modality in patients with pathological medial plica disease of the knee either as a first-line treatment or when symptoms have not responded to non-surgical interventions.

Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Fig. 1. Study flow diagram.
Fig. 2. Meta-analysis of outcomes rated as good and excellent following arthroscopic excision of medial knee plica. CI: confidence interval.
Fig. 3. Meta-analysis of outcomes rated as good and excellent following arthroscopic excision of medial knee plica in patients previously treated by conservative methods. CI: confidence interval.

Summary of Study Demographics, Outcomes, and Complications

Author Year Journal Study type No. of knees (n=643) Age (yr) Sex (M:F) Non-operative management prior to surgery Operation performed Follow-up time (mo) Outcome Complication Included in meta-analysis
Moller21) 1981 Acta Orthopaedica Scandinavica Prospective 78 31.2 51:28 Excision of the medial plica±Z-plasty 11 Without symptoms: 66
Slight symptoms: 8
Unchanged: 1
Worse: 1
Chronic synovitis: 2
Klein25) 1983 Archives of Orthopaedic and Traumatic Surgery Retrospective 17 Excision of the medial plica Apr–42 Excellent: 7
Good: 6
Fair: 1
Poor: 3
Bough and Regan22) 1985 Irish Medical Journal Prospective 23 23 (15–56) 3:1 Yes Excision or division of plica 18 (12–48) Excellent: 16
Good: 5
Fair: 0
Poor: 2
No complications Yes
Andersen and Poulsen23) 1986 Archives of Orthopaedic and Traumatic Surgery Prospective 31 31 (15–44) 20:8 Excision of the medial plica 15 (7–29) Excellent: 12
Good: 14
Fair: 4
Poor: 0
No complications Yes
Brabants et al.26) 1988 Acta Orthopaedica Belgica Retrospective 161 Release of the plica Complaint free: 128
Not complaint free: 33
Dorchak et al.27) 1991 The American Journal of Sports Medicine Retrospective 51 24.9 (17–40) Yes Excision of the medial plica 46.8 (15–77) Excellent: 22
Good: 16
Fair: 0
Poor: 13
Maffulli et al.15) 1993 Medicine and Science in Sports and Exercise Prospective 102 26.5 (18–40) Yes Excision of the medial plica 43 (9–87) No complaints: 67
Not able to perform best at sport, work & social life not affected: 11
Sport affected, able to work: 14
Limited daily activities of living: 10
6 Haematomas No
Farkas et al.28) 1997 Acta Chirurgica Hungarica Retrospective 14 23.6 (15–43) 1:1 Excision of the medial plica 18 (7–35) Excellent: 4
Good: 9
Fair: 0
Poor: 1
No complications Yes
Yilmaz et al.16) 2005 International Orthopaedics RCT between different plica exicions 23 45.1 1:2 Yes Excision of the medial plica 30 (24–36) Excellent: 5
Good: 10
Fair: 2
Poor: 6
20/23 Self resolving effusions Yes
Shetty et al.24) 2007 Journal of Knee Surgery Prospective 44 45 (15–65) Resection of the plica 3 Satisfactory: 39
Unsatisfactory: 5
Uysal et al.17) 2008 International Orthopaedics Retrospective 23 42.4 (23–60) 14:8 Yes Plica resected with punch and then shaved 21 (13–24) All patients regained full range of movement
Average Lysholm knee scale score: preoperative, 67.19±8.05, postoperative, 90.57±9.80
2/23 Self resolving effusions No
Guney et al.29) 2010 Knee Surgery, Sports Traumatology, Arthroscopy Retrospective 76 37.2 (15–61) 44:32 Excision of the medial plica 6 Excellent: 72
Good: 2
Fair: 2
Poor: 0
Mean WOMAC score:
preoperative, 1.4±0.7/1.3 (0–3.04)
postoperative, 0.2±0.5/0 (0–2.42)

Values are presented as mean (range).

RCT: randomized controlled trial, WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index.

Methodological Index for Non-Randomized Studies Assessment of Included Studies

Criteria Moller21) Klein25) Bough and Regan22) Andersen and Poulsen23) Brabants et al.26) Dorchak et al.27) Maffulli et al.15) Farkas et al.28) Yilmaz et al.16) Shetty et al.24) Uysal et al.17) Guney et al.29)
A clearly stated aim 2 2 2 2 2 2 2 2 2 2 2 2
Inclusion of consecutive patients 2 2 2 2 2 2 2 2 2 2 2 2
Prospective collection of data 2 0 0 2 0 0 2 0 2 2 0 2
Endpoints appropriate to the aim of study 2 2 2 2 2 2 2 2 2 2 2 0
Unbiased assessment of study endpoint 0 0 0 0 0 0 0 0 0 0 0 2
Follow-up appropriate to the aim of study 2 2 2 2 0 2 2 2 2 1 2 0
Loss to follow-up, <5% 2 2 2 2 2 2 2 2 2 2 2 2
Prospective calculation of study size 0 0 0 0 0 0 0 0 0 0 0 0
Total 12 10 10 12 8 10 12 10 12 11 10 10

The items are scored 0 (not reported), 1 (reported but inadequate) or 2 (reported and adequate), with maximum possible score being 16.

  1. Blok, A, Weiss, W, Dolata, T, and Szczepaniec, M (2005). Medial synovial plica. Ortop Traumatol Rehabil. 7, 397-400.
  2. Nakayama, A, Sugita, T, Aizawa, T, Takahashi, A, and Honma, T (2011). Incidence of medial plica in 3,889 knee joints in the Japanese population. Arthroscopy. 27, 1523-7.
    Pubmed CrossRef
  3. Matsusue, Y, Ueo, T, and Yamamuro, T (1991). Arthroscopic resection of the shelf (mediopatellar plica) in the knee under local anesthesia in outpatient clinic. Nihon Geka Hokan. 60, 176-83.
  4. Muse, GL, Grana, WA, and Hollingsworth, S (1985). Arthroscopic treatment of medial shelf syndrome. Arthroscopy. 1, 63-7.
    Pubmed CrossRef
  5. Richmond, JC, and McGinty, JB (1983). Segmental arthroscopic resection of the hypertrophic mediopatellar plica. Clin Orthop Relat Res, 185-9.
    Pubmed CrossRef
  6. O’Dwyer, KJ, and Peace, PK (1988). The plica syndrome. Injury. 19, 350-2.
  7. Kent, M, and Khanduja, V (2010). Synovial plicae around the knee. Knee. 17, 97-102.
    Pubmed CrossRef
  8. Ewing, JW (1993). Plica: pathologic or not?. J Am Acad Orthop Surg. 1, 117-21.
    Pubmed CrossRef
  9. Dandy, DJ (1987). Arthroscopic management of the knee. Edinburgh: Churchill Livingstone, pp. 64-71
  10. Bellary, SS, Lynch, G, Housman, B, Esmaeili, E, Gielecki, J, Tubbs, RS, and Loukas, M (2012). Medial plica syndrome: a review of the literature. Clin Anat. 25, 423-8.
    Pubmed CrossRef
  11. Amatuzzi, MM, Fazzi, A, and Varella, MH (1990). Pathologic synovial plica of the knee: results of conservative treatment. Am J Sports Med. 18, 466-9.
    Pubmed CrossRef
  12. Laprade, RF, and Wentorf, F (1999). Acute knee injuries; on-the-field and sideline evaluation. Phys Sportsmed. 27, 55-61.
    Pubmed CrossRef
  13. Weckstrom, M, Niva, MH, Lamminen, A, Mattila, VM, and Pihlajamaki, HK (2010). Arthroscopic resection of medial plica of the knee in young adults. Knee. 17, 103-7.
    Pubmed CrossRef
  14. Griffith, CJ, and LaPrade, RF (2008). Medial plica irritation: diagnosis and treatment. Curr Rev Musculoskelet Med. 1, 53-60.
    Pubmed KoreaMed CrossRef
  15. Maffulli, N, Testa, V, and Capasso, G (1993). Mediopatellar synovial plica of the knee in athletes: results of arthroscopic treatment. Med Sci Sports Exerc. 25, 985-8.
    Pubmed CrossRef
  16. Yilmaz, C, Golpinar, A, Vurucu, A, Ozturk, H, and Eskandari, MM (2005). Retinacular band excision improves outcome in treatment of plica syndrome. Int Orthop. 29, 291-5.
    Pubmed KoreaMed CrossRef
  17. Uysal, M, Asik, M, Akpinar, S, Ciftci, F, Cesur, N, and Tandogan, RN (2008). Arthroscopic treatment of symptomatic type D medial plica. Int Orthop. 32, 799-804.
    Pubmed KoreaMed CrossRef
  18. Schindler, OS (2014). ‘The Sneaky Plica’ revisited: morphology, pathophysiology and treatment of synovial plicae of the knee. Knee Surg Sports Traumatol Arthrosc. 22, 247-62.
    Pubmed CrossRef
  19. Moher, D, Liberati, A, Tetzlaff, J, Altman, DG, and PRISMA Group (2010). Preferred reporting items for systematic reviews and metaanalyses: the PRISMA statement. Int J Surg. 8, 336-41.
    Pubmed CrossRef
  20. Slim, K, Nini, E, Forestier, D, Kwiatkowski, F, Panis, Y, and Chipponi, J (2003). Methodological index for non-randomized studies (minors): development and validation of a new instrument. ANZ J Surg. 73, 712-6.
    Pubmed CrossRef
  21. Moller, H (1981). Incarcerating mediopatellar synovial plica syndrome. Acta Orthop Scand. 52, 357-61.
    Pubmed CrossRef
  22. Bough, BW, and Regan, BF (1985). Medial and lateral synovial plicae of the knee: pathological significance, diagnosis and treatment by arthroscopic surgery. Ir Med J. 78, 279-82.
  23. Andersen, E, and Poulsen, TD (1986). Plica mediopatellaris: arthroscopic resection under local anesthesia. Arch Orthop Trauma Surg. 106, 18-9.
    Pubmed CrossRef
  24. Shetty, VD, Vowler, SL, Krishnamurthy, S, and Halliday, AE (2007). Clinical diagnosis of medial plica syndrome of the knee: a prospective study. J Knee Surg. 20, 277-80.
    Pubmed CrossRef
  25. Klein, W (1983). The medial shelf of the knee: a follow-up study. Arch Orthop Trauma Surg. 102, 67-72.
    Pubmed CrossRef
  26. Brabants, K, Geens, S, and Blondeel, L (1988). Plica synovialis mediopatellaris. Acta Orthop Belg. 54, 474-6.
  27. Dorchak, JD, Barrack, RL, Kneisl, JS, and Alexander, AH (1991). Arthroscopic treatment of symptomatic synovial plica of the knee. Long-term followup. Am J Sports Med. 19, 503-7.
    Pubmed CrossRef
  28. Farkas, C, Gaspar, L, and Jonas, Z (1997). The pathological plica in the knee. Acta Chir Hung. 36, 83-5.
  29. Guney, A, Bilal, O, Oner, M, Halici, M, Turk, Y, and Tuncel, M (2010). Short- and mid-term results of plica excision in patients with mediopatellar plica and associated cartilage degeneration. Knee Surg Sports Traumatol Arthrosc. 18, 1526-31.
    Pubmed CrossRef
  30. Sakakibara, J (1976). Arthroscopic study on linos band (plica synovia is mediopatellaris). J Jpn Orthop Assoc. 50, 513-22.


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