Definition
Pigmented Villo-Nodular Synovitis
- benign proliferation of the synovium
- AKA tenosynovial giant cell tumour
Epidemiology
Age: 20 - 50
Male:Female 1:1
Most common in the knee
Types
A. Localised
- just one area of synovium
- i.e. suprapatellar / medial or lateral gutter / posterior compartment
B. Diffuse
- throughout joint
- anterior and posterior
- more difficult to excise fully
Site
Knee most common
- also hip / shoulder / ankle
- usually mono-articular / rarely poly-articular
- case series of 237 patients with PVNS
- 74% knee
- 18% hip
Etiology
Translocations of chromosome 1p13
- present in the majority of PVNS cases
- overexpressing colony-stimulating factor 1 (CSF1)
Natural History
The process is intermittently progressive
- over a period of several months or years
- diffuse synovial involvement
Progressive destruction of the articular cartilage and subchondral bone
In aggressive cases, PVNS may involve adjacent bone
Clinical
Insidious onset
Joint swelling / effusion
May present after years of symptoms
Aspirate
Blood tinged fluid in absence of trauma
X-ray
Soft tissue swelling
Arthritic changes
Bone destruction
- invasion of adjacent metaphyseal cancellous bone
- may be suggestive of neoplasm
Bony involvement PVNS
MRI
Synovial thickening
Hemosiderin
- low signal intensity on TI and T2 - "drop out" signals
- blooming on gradient echo
Localized / nodular
Localized PVNS of the notch
Localized posterolateral PVNS
Diffuse
Diffuse PVNS with involvement of suprapatella pouch and posterior compartments, including posterior extra-articular
Severe diffuse PVNS with bony involvement
Differential diagnosis
Haemophilia
Lipoma arborescens
Synovial chondromatosis
Arthroscopy
Localized / nodular PVNS anterior knee joint
Localized / nodular PVNS posteromedial compartment knee
Diffuse knee joint
Pathology
Histology
Hemosiderin stained multinucleated giant cells
Management
Synovectomy
Complete synovectomy
- dissecting the synovium and intermediate layers
- preserve deep fibrous layers and ligaments
- need to remove all affected synovium for best results
- meticulous surgical technique required
Issue
Recurrence
Mastboom et al Lancet Oncol 2019
- multicentred study of diffuse PVNS in 966 patients treated surgically
- recurrence rate 44%
Medical treatments
Radiotherapy
- 50 patients with diffuse PVNS
- treated with surgery and radiotherapy
- recurrence rate 6%
Heyd et al Int J Radiat Oncol Biol Phys 2010
- 41 patients receiving postoperative radiotherapy
- single dose
- recurrence 5%
- mild early and late toxicity
Radiosynoviorthesis
Yttrium labelled colloid injections
Gortzak et al Bone Joint J 2018
- patients with diffuse PVNS knee
- retrospective analysis between 1991 and 2014
- 34 patients with synovectomy and Yttrium: residual disease 15/34
- 22 patients synovectomy alone: residual disease 11/22
- inconclusive benefit
Pexidartinib
Tyrosine kinase inhibitor / CSFR1 inhibitor
- 120 patient RCT of pexidartinib v placebo
- patients not amenable to surgery
- 39% response rate to pexidartinib
- 70% hair colour change, 50% fatigue
- 40% elevation of liver enzymes
Knee
Arthroscopic synovectomy
Vumedi localized anterior PVNS
Surgical technique video transeptal portal posterior PVNS
Anterior
- suprapatella
- medial and lateral gutters
- ACL / PCL
Posterior compartments
- posteromedial / posterolateral
- transeptal portal
Open posterior synovectomy
Extracapsular nodules
Surgical technique posterior approach for PVNS
Removal of extra-articular PVNS via direct posterior approach
Results of synovectomy
Auregan et al Arthroscopy 2014
- systematic review of 6 studies and 1000 patients
- recurrence rate localized: 9% open, 7% arthroscopic
- recurrence rate diffuse: 23% open, 16% arthroscopic
- complications rate: 19% open, 0% arthroscopic
Results of TKA
Tan et al Knee Surg Rel Res 2021
- systematic review of 5 studies with 550 TKA in setting of PVNS
- recurrence of PVNS 7% (all diffuse PVNS)
- stiffness in 6%
- infection 2.9%
Casp et al J Arthroplasty 2018
- database study of 453 patients with PVNS of the knee
- no difference in revision rate at 2 years
- increased stiffness compared to control group: 7% v 5%
- increased infection compared to control group: 3% v 1.5%
Hip
Results of synovectomy
Chen et al Arthroscopy 2013
- 32 hips treated with arthroscopic synovectomy
- recurrence rate 6%
- 37 cases treated with open synovectomy
- recurrence rate 8%
Results of THA
Ardeljan et al J Arthroplasty 2021
- registry data of 1240 patients with PVNS undergoing THA
- 2% aseptic loosening at 2 years
- 22 patients with PVNS undergoing total synovectomy and THA
- average age 35 years with 8 years follow up
- no recurrent
- 90% 10 year survivorship similar to matched controls
Ankle
Surgical technique ankle arthroscopy for PVNS
Results
- systematic review of 25 studies and 382 patients with PVNS foot and ankle
- diffuse: recurrence rate 21%
- localized: recurrence rate 7%
Barnet et al Foot Ankle Int 2023
- 123 cases ankle PVNS
- recurrence rate 37% with diffuse PVNS
- patients with pain and pre-operative erosive change - 57% had postoperative pain