Pigmeted Villonodular Synovitis

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Definition/Description[edit | edit source]

Pigmented Villonodular Synovitis, also known as PVNS, is a rare idiopathic proliferative disorder of the synovium that leads to villous and or nodular formations within joints, tendon sheaths and bursae. It affects adults between twenty and sixty years old, independent of the gender. It may also uncommonly appear in children . Despite the disease is benign, PVNS can be aggressive, spreading to surrounding synovial tissues and invading adjacent soft tissue structures and bone, resulting in effusions and bony erosion.

Clinically Relevant Anatomy[edit | edit source]

Any joint can be affected but PVNS occurs mostly in the knee (80%), followed by the hip and the ankle (foot). To a lesser degree in the wrist, shoulder and elbow. It may also appear in the spine, but it is infrequent.
The synovium, tendon sheaths, bursae and bone can be involved by patients with PVNS. In the spine, the disease originates from the vertebral articular facet joints .

Characteristics/Clinical Presentation[edit | edit source]

The symptoms by patients with PVNS are sporadic or slowly progressive [5]. Some may experience pain, swelling, warmth and stiffness in the joint [5][8]. Locking and instability, mechanical symptoms, may develop [5]. PVNS in the spine may cause back pain, tenderness, and neurological dysfunction leading to acute paralysis [13].

PVNS is characterized by a unique gross and histologic structure consisting of brownish villous and nodular masses arising on the surface of synovial tissue and consisting of fibrous elements, hemosiderin containing macrophages, lipid-filled foam cells, multinucleated giant cells, and some inflammatory cells [1][5][7][9]. Hemosiderin is an iron-rich pigment, responsible for the brownish rusty colour [2][5][14]. 
Bilateral is rare, PVNS mostly occurs only in one joint (monoarticular) [1][8][9][6].
These characteristics count for both localized and diffuse PVNS [5][9].
The disease has a high risk of recurrence, but also a variant recurrence rate of 8% to 60% [1][11].

Differential Diagnosis[edit | edit source]

Diagnosing PVNS is relatively easily (on the basis of MRI etc.), but in the knee it is more difficult because the clinical presentation and symptoms are similar with more common disorders at the joint, such as internal derangements or arthritis [3][7].

Diagnostic Procedures[edit | edit source]

Results of laboratory studies, such as a complete blood count and erythrocyte sedimentation rate, are within normal limits and can help exclude infection and rheumatoid arthritis [5].
Joint aspiration reveals a brown, red or yellow fluid [5].
Radiographs reveal, in earlier stages, periarticular synovial swelling, absence of synovial calcification, normal bone density, and preservation of the cartilage space [1][5].
A magnetic resonance image (MRI) will show nodular foci of decreased signal on both T1 and T2 images, because of the release of hemosiderin. Additionally, low signal on fast field echo (FFE) sequences are helpful in the diagnosis of PVNS [5].
If the diagnosis still remains in question, an arthroscopic exam can show the gross appearance of the lesion [5].
A biopsy can confirm the diagnosis of PVNS [5].
The diagnosis by PVNS in the spine can be confirmed by histopathology [13].

Outcome Measures[edit | edit source]

Patients can be evaluated according to the Knee Society Score [1].

Medical Management[edit | edit source]

Good results can be obtained with local excision of a solitary nodule [5][7][11]. However, once diffuse PVNS is diagnosed, a total synovectomy is recommended [2][5][12]. Arthroscopic resection may be useful, if the MRI shows the lesion to be accessible by arthroscopy, and if it is associated with relatively low morbidity [5][9]. But an open synovectomy may be necessary because lesions extend beyond the reach of the arthroscope [1][5]. Unfortunately, synovectomy has a high recurrence rate [2][5][11].  This also applies  to arthroscopic synovectomy [5]. But actually it is the type of surgery and the disease subtype that is associated with recurrence [11].
If diffuse PVNS is diagnosed, especially in an older patient with degenerative joint disease, an arthroplasty can give good outcomes [5]. In a younger patient, arthrodesis may be considered as a savage procedure [5].
Radiation therapy is recommended as an adjuvant to surgery to control the disease process [1][5][7][9].
Intra-articular injection of yttrium 90 or dysprosium after surgery can be used to treat diffuse PVNS [5][10].  But the effectiveness is inconclusive [5][7].
Eventually, a total joint replacement can be required, particularly in the hip [7]. 

Physical Therapy Management[edit | edit source]

Physical therapy before PVNS is diagnosed or before surgery, is unsuccessful. .
Postoperative rehabilitation can obtain good results, but it is not yet established. .
Because PVNS is considered as a rheumatic disease, the same therapy may be used [5].

Surgery of the hip mostly lead to a total joint replacement. The physical therapy after such surgery is already described.

References [edit | edit source]

[1] Akinci O, Akalin Y, Incesu M, Eren A. Long-term results of surgical treatment of pigmented villonodular synovitis of the knee. Acta Orthopaedica Et Traumatologica Turcica 2011; 45(3):149-155. http://www.aott.org.tr/index.php/aott/article/view/4976/2716

[2] Garner HW, Ortiguera C, Nakhleh RE. Best Cases from the AFIP: Pigmented Villonodular Synovitis. RG 2008, Vol:28, No: 5. (Level of Evidence: 4)  http://radiographics.rsna.org/content/28/5/1519.full.pdf+html

[3] Hegedus EJ, Theresa K. Postoperative management of pigmented villonodular synovitis in a single subject. J Orthop Sports Phys Ther. 2008 Dec; 38(12):790-7.

[4] Huang GS, Lee CH, Chan WP, Chen CY, Yu JS, Resnick D. Localized Nodular Synovitis of the Knee: MR Imaging Appearance and Clinical Correlates in 21 Patients. AJR:181, August 2003. (Level of Evidence: 2B)  http://www.ajronline.org/content/181/2/539.full.pdf+html

[5] Klippel JH. Primer on the Rheumatic Diseases. New York: Springer, 2008.

[6] Krause FG, Wroblewski JA, Younger ASE. Pigmented villonodular synovitis in both hindfeet. Can J Surg. 2009 April; 52(2): E38–E39. (Level of Evidence: 4) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2673156/pdf/20090400s00025pE38.pdf

[7] Mankin H, Trahan C, Hornicek F. Pigmented Villonodular Synovitis of Joints. Journal of Surgical Oncology 2011; 103:386-389. (Level of Evidence: 2C)

[8] Neubauer P, Weber K, Miller NH, McCarthy EF. Pigmented Villonodular Synovitis in Children: A report of six cases and review of the literature. Iowa Orthop J. 2007; 27:90–94. (Level of Evidence: 4) http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2150657/pdf/iowa0027-0090.pdf

[9] Schnirring-Judge M, Lin B. Pigmented Villonodular Synovitis of the Ankle – Radiation Therapy as a Primary Treatment to Reduce Recurrence: A Case Report with 8-year Follow-up. The Journal of Foot & Ankle Surgery 50. 2001; 108-116. (Level of Evidence: 4)

[10] Shabat S, Kollender Y, Merimsky O, Isakov J, Flusser G, Nyska M, Meller I. The use of surgery and yttrium 90 in the management of extensive and diffuse pigmented villonodular synovitis of large joints. Rheumatology 2002; 41:1113-1118. (Level of Evidence: 1B)

[11] Sharma V, Cheng EY. Outcomes after Excision of Pigmented Villonodular Synovitis of the Knee. Clin Orthop Relat Res. 2009; 467:2852-2858. (Level of Evidence: 4)

[12] Wyatt MC, Rolton N, Veale GA. Pigmented villonodular synovitis of the elbow with a fenestrated fossa: a case report. Journal of Orthopaedic Surgery 2009; 17(1):127-9.
(Level of Evidence: 4) http://www.josonline.org/pdf/v17i1p127.pdf

[13] Yener U, Konya D, Bozkurt S, Ozgen S. Pigmented Villonodular Synovitis of the Spine: Report of a Lumbar Case. Turkisch Neurosurgery 2010, Vol:20, No: 2, 251-256.
(Level of Evidence: 4) http://www.turkishneurosurgery.org.tr/pdf/pdf_JTN_750.pdf

[14] http://medical-dictionary.thefreedictionary.com/hemosiderin