Jump to content
We need you! See something you could improve? Make an edit and help improve WikSM for everyone.

Bakers Cyst

From WikiSM

Other Names

  • Popliteal synovial cyst
  • Ganglion cyst of the knee
  • Synovial cyst of the knee
  • Baker's Cyst
  • Parameniscal cyst
  • Perimeniscal cyst
  • Meniscal cyst
  • Pseudothrombophlebitis Syndrome
  • Primary popliteal cyst

Background

  • This page refers to a synovial or ganglion cyst of the knee, which when presenting posteriorly is referred to as a Baker's Cyst (BC)

History

  • Named after British surgeon William Morant Baker’s case series published in 1877[1]
  • First described by Robert Adams in 1840[2], and subsequently by Foucher in 1856[3]
  • Further characterized by Wilson in 1938 who dissected 30 knees, of which 58% had a direct connection with the knee joint[4]

Epidemiology

  • Found on 38% of knee MRIs on symptomatic patients[5]
  • Found in 40-54% of adult knees based on cadaveric studies[6]
  • Most commonly seen in adults between ages 35 and 70 (need citation)
  • Pediatric
    • Among children, most frequently seen between ages 4 and 7, reported in children as young as 2[7]
    • In pediatric knee MRI, prevalence estimated at 6.3%[8]

Pathophysiology

Important anatomical landmarks associated with where popliteal cysts commonly form. It is essential to understand the anatomy of the knee because popliteal cysts normally form as an extension of the semimembranosus bursa in the posteromedial portion of the knee. They typically lie between the semimembranosus and the medial head of the gastrocnemius.[9]
Comparison of Knee Joint Anatomy (A) Normal; (B) Baker's Cyst patient[10]
A large bakers cyst is seen in the popliteal fossa[11]
Surgical approaches to a bakers cyst[12]

General

  • A bakers cyst is a type of synovial cyst that forms between the semimembranosus and medial head of the gastroc
  • It can be an incidental finding or the cause of the patients pain
  • It is easily diagnosed on ultrasound or MRI
  • Treatment is initially conservative but definitive care is surgical

Anatomy of the Semimembranosus Gastrocnemius Bursa

  • General
    • Bursal communication between the Semimembranosus (SemiM) and medial head of the Gastrocnemius (Gastroc)
    • There may be occasional involvement of the subgastrocnemius bursa[13]
    • Case report of synvial cyst herniating out laterally through the Iliotibial Band[14]
  • 1 way valve[15]
    • Allows synovial fluid to pass into bursa where it is sequestered
    • In flexion, valve is open allowing flow
    • In extension, valve is closed due to muscle tension of SemiM and Gastroc
  • Function
    • May provide protective effect against hydraulic pressure from knee effusions
    • Size of BC roughly correlates with size of knee effusion[16]

Histology

  • Cyst walls resemble synovial tissue with fibrosis suggesting chronic nonspecific inflammation[17]
  • Cyst fluid is often thickened by the presence of fibrin
  • Rauschnig et al found no difference in histopathology between symptomatic and asymptomatic knees

Pediatric considerations

  • Majority have no communication with the joint capsule and may arise spontaneously[18]
  • When they do communicate with the joint, resemble those seen in adults

Associated Pathology

Risk Factors

Differential Diagnosis

Differential Diagnosis Knee Pain

Clinical Features

Bakers cyst seen in the popliteal fossa[22]

History

  • Patients may report insidious, posterior knee pain
  • Additionally fullness, achiness, mass, and stiffness
  • The most common symptoms are swelling (76%), posterior aching (32%)[23]
  • Pain with full or terminal knee extension
  • Often have symptoms consistent with meniscal or chondral injuries

Physical Exam: Physical Exam Knee

  • Findings often consistent with meniscal or chondral injuries
  • With large cysts, posteromedial fullness may be present but many smaller cysts are not palpable

Special Tests

  • Foucher Sign: Examine posterior mass in full knee extension and flexion, should be soft in flexion
  • Homan Sign: Extend knee, passively dorsiflex ankle and squeeze calf

Evaluation

Bakers Cyst ultrasound long axis
Bakers Cyst ultrasound short axis
Baker’s cyst in a 33-year-old man presenting with nonspecific intermittent knee pain. Sagittal FS PD-weighted MRI (a) shows a hyperintense multiloculated fluid collection surrounding the medial gastrocnemius tendon. Its typical emergence between the medial head of the gastrocnemius muscle and the semimembranosus tendon is more evident on the axial view (b), as well as an intramuscular extension in its lateral aspect (arrow). MGc, medial gastrocnemius; Sm, semimembranosus[24]

Radiographs

  • Standard Knee Radiographs
    • Screening tool
    • Not typically useful for evaluating a bakers cyst
  • Can detect other pathology associated with bakers cyst
    • E.g.: Osteoarthritis, Gout, Osteochondral Defect
    • Loose bodies may be seen within the bakers cyst
  • Arthrography
    • Previously gold standard for evaluation[25]
    • Has fallen out of favor for MRI, US

Ultrasound

  • Advantages
    • Cheap, lacks radiation, ease of use
  • Disadvantages
    • User dependent, cant evaluate all soft tissue injuries
  • Findings
    • Anechoic or hypoechoic, circumferential structure
    • Lacks flow and doppler signal of vascular structures
  • Accuracy[26]
    • Sensitivity: 100%
    • Specificity: 100%
    • PPV: 100%
    • NPV: 100%
    • Accuracy: 100%

MRI

  • Gold standard for evaluating BC and other soft tissue structures
  • Findings
    • Appear as a water-intensity fluid collection (low signal intensity on T1, high signal intensity on T2-weighted images)[20]
  • Description
    • Most are small, unilocular but can also be septated or multiloculated
    • Size, sites of extension, rupture can change appearance of fluid collection
    • Loose bodies/debris can be present

Classification

  • No specific classification
  • Important to characterize
    • Communicating vs noncommunicating
    • Loculated, multiloculated or septated
    • Underlying etiology

Management

Needle and probe position for long axis approach (top) and short axis (bottom) to Bakers Cyst Aspiration and Injection[27]

Nonoperative

  • General
    • Initial treatment of choice unless complications
    • Important to target the underlying disorder
  • Physical Therapy
    • Maintain range of motion and knee flexibility
  • Intra-articular Corticosteroid Injection
    • Intra-articular has been found to decrease size, symptoms of cyst[28]
  • Bakers Cyst Aspiration and Injection
    • This is particularly valuable in the uncommon noncommunicating, multiloculated or septated cyst

Operative

  • Indications
    • Failure of conservative therapy
    • Complicated including infection, neurovascular insult
  • Technique
    • Arthroscopic debridement
    • Arthroscopic cyst decompression or excision
    • Less commonly, open cyst excision
    • Correction of intra-articular pathology

Rehab and Return to Play

Rehabilitation

  • Rehab should begin early and include[29]
    • Knee and core stabilizer strength
    • Flexibility
    • Functional independence

Return to Play

  • General RTP guidelines[30]
    • Confirm anatomical and functional healing
    • Restoration of sport-specific skills
    • Psychosocial readiness

Prognosis and Complications

Prognosis

  • General
    • Prognosis is generally favorable with appropriate conservative or minimally invasive treatment
  • Conservative
    • Most patients experience significant symptom relief and reduction in cyst size with conservative measures[31]
    • Ultrasound-guided aspiration and corticosteroid injection can further improve pain and function[32]
  • Surgical
    • Response to surgical excision seems to correlate with ability to correct intra-articular pathology
    • Rauschning et al: 46 surgical excisions, 63% recurred, 33% had wound complications or pseudothrombophlebitis after[33]
    • Rupp et al: Arthroscopic treatment for 16 intra-articular disorders, 11 cysts persisted of which 2 became larger at 1 year postop[34]
      • Chondral lesions appeared to be most important prognostic factor, all patients had outerbridge III or IV lesions

Complications

See Also

Internal

External

References

  1. ↑ Baker WM. On the formation of synovial cysts in the leg in connection with disease of the knee joint. 1877. Clin Orthop Relat Res. 1994;299:2-10.
  2. ↑ Adams R. Chronic rheumatic arthritis of the knee joint. Dublin J Med Sci. 1840;17:520-522.
  3. ↑ Foucher E. Memoire sur les kystes de la region poplitee. Arch Gen Med. 1856;2:313.
  4. ↑ Wilson PD, Eyre-Brook AL, Francis JD. A clinical and anatomical study of the semimembranosus bursa in relation to popliteal cyst. J Bone Joint Surg Am. 1938;20:963-984.
  5. ↑ 5.0 5.1 Sansone V, De Ponti A, Minio Paluello G, Del Maschio A. Popliteal cysts and associated disorders of the knee: critical review with MR imaging. Int Orthop. 1995;19:275-279.
  6. ↑ Taylor AR, Rana NA. A valve: an explanation of the formation of popliteal cysts. Ann Rheum Dis. 1973;32:419-421
  7. ↑ GRISTINA, ANTHONY G., and PHILIP D. WILSON. "Popliteal cysts in adults and children: a review of 90 cases." Archives of Surgery 88.3 (1964): 357-363.
  8. ↑ De Maeseneer, Michel, et al. "Popliteal cysts in children: prevalence, appearance and associated findings at MR imaging." Pediatric radiology 29.8 (1999): 605-609.
  9. ↑ Brazier, Brett G., et al. "Arthroscopic treatment of popliteal cysts." Arthroscopy techniques 7.11 (2018): e1109-e1114.
  10. ↑ Hutagalung, Muhammad Bayu Z., Panji Anugerah, and Safrizal Rahman. "The Role of Ultrasonography Exam in Baker’s Cyst: Case Report." The 1st Syiah Kuala International Conference on Medical and Health Sciences. 2017.
  11. ↑ Hafez, İzzet, et al. "A rare presentation of a saccular aneurysm of the popliteal vein: A case report." Turkish Journal of Vascular Surgery 30.2 (2021).
  12. ↑ Frush, Todd J., and Frank R. Noyes. "Baker’s cyst: diagnostic and surgical considerations." Sports health 7.4 (2015): 359-365.
  13. ↑ Akagi, Ryuichiro, et al. "Natural history of popliteal cysts in the pediatric population." Journal of Pediatric Orthopaedics 33.3 (2013): 262-268.
  14. ↑ Jensen KH, Jorgensen U. Lateral presentation of a Baker’s cyst. Clin Orthop Relat Res. 1993;287:202-203
  15. ↑ Rauschning W. Anatomy and function of the communication between the knee joint and popliteal bursae. Ann Rheum Dis. 1980;39:354-358.
  16. ↑ Hill CL, Gale DG, Chaisson CE, et al. Knee effusions, popliteal cysts, and synovial thickening: association with knee pain in osteoarthritis. J Rheumatol. 2001;28:1330-1337.
  17. ↑ Rauschning W, Fredriksson BA, Wilander E. Histomorphology of idiopathic and symptomatic popliteal cysts. Clin Orthop Relat Res. 1982;164:306-311.
  18. ↑ Akagi, Ryuichiro, et al. "Natural history of popliteal cysts in the pediatric population." Journal of Pediatric Orthopaedics 33.3 (2013): 262-268.
  19. ↑ Tarhan S, Unlu Z. Magnetic resonance imaging and ultrasonographic evaluation of the patients with knee osteoarthritis: a comparative study. Clin Rheumatol. 2003;22:181-188.
  20. ↑ 20.0 20.1 Marti-Bonmati L, Molla E, Dosda R, Casillas C, Ferrer P. MR imaging of Baker cysts: prevalence and relation to internal derangements of the knee. MAGMA. 2000;10:205-210.
  21. ↑ Corten K, Vandenneucker H, Reynders P, Nijs S, Pittevils T, Bellemans J. A pyogenic, ruptured Baker’s cyst induced by arthroscopic pressure pump irrigation. Knee Surg Sports Traumatol Arthrosc. 2009;17:266-269
  22. ↑ Image courtesy of https://orthoinfo.aaos.org/
  23. ↑ Bryan RS, DiMichele JD, Ford GL., Jr. Popliteal cysts. Arthrography as an aid to diagnosis and treatment. Clin Orthop Relat Res. 1967;50:203-208.
  24. ↑ Neto, Nelson, and Pedro Nunnes. "Spectrum of MRI features of ganglion and synovial cysts." Insights into imaging 7 (2016): 179-186.
  25. ↑ Torreggiani WC, Al-Ismail K, Munk PL, et al. The imaging spectrum of Baker’s (popliteal) cysts. Clin Radiol. 2002;57:681-691.
  26. ↑ Ward EE, Jacobson JA, Fessell DP, Hayes CW, van Holsbeeck M. Sonographic detection of Baker’s cysts: comparison with MR Imaging. AJR Am J Roentgenol. 2001;176:373-380.
  27. ↑ Malanga, Gerard A., and Kenneth R. Mautner. "Atlas of ultrasound-guided musculoskeletal injections." (No Title) (2014).
  28. ↑ Acebes JC, Sanchez-Pernaute O, Diaz-Oca A, Herrero-Beaumont G. Ultrasonographic assessment of Baker’s cysts after intra-articular corticosteroid injection in knee osteoarthritis. J Clin Ultrasound. 2006;34:113-117
  29. ↑ Herring, Stanley A., et al. "Initial assessment and management of select musculoskeletal injuries: a team physician consensus statement." Current Sports Medicine Reports 23.3 (2024): 86-104.
  30. ↑ Herring, Stanley A., et al. "Team Physician Consensus Statement: Return to Sport/Return to Play and the Team Physician: A Team Physician Consensus Statement—2023 Update." Current sports medicine reports 23.5 (2024): 183-191.
  31. ↑ Curl, Walton W. "Popliteal cysts: historical background and current knowledge." JAAOS-Journal of the American Academy of Orthopaedic Surgeons 4.3 (1996): 129-133.
  32. ↑ Di Sante, Luca, et al. "Ultrasound-guided aspiration and corticosteroid injection of Baker's cysts in knee osteoarthritis: a prospective observational study." American journal of physical medicine & rehabilitation 89.12 (2010): 970-975.
  33. ↑ Rauschning W, Lindgren PG. Popliteal cysts (Baker’s cysts) in adults: I. Clinical and roentgenological results of operative excision. Acta Orthop Scand. 1979;50:583-591
  34. ↑ Rupp S, Seil R, Jochum P, Kohn D. Popliteal cysts in adults: prevalence, associated intraarticular lesions, and results after arthroscopic treatment. Am J Sports Med. 2002;30:112-115.
  35. ↑ Eichinger JK, Bluman EM, Sides SD, Arrington ED. Surgical management of septic arthritis of the knee with a coexistent popliteal cyst. Arthroscopy. 2009;25:696-700.
  36. ↑ Ji JH, Shafi M, Kim WY, Park SH, Cheon JO. Compressive neuropathy of the tibial nerve and peroneal nerve by a Baker’s cyst: case report. Knee. 2007;14:249-252.
Created by:
John Kiel on 16 December 2020 21:18:39
Authors:
Last edited:
20 November 2025 00:01:28
Categories:
Retrieved from "https://wikism.org/w/index.php?title=Bakers_Cyst&oldid=38506"