PVNS

Definition

 

Pigmented Villo-Nodular Synovitis

- benign inflammatory process that arises in synovial tissues

- contains significant amounts of hemosiderin

 

Epidemiology

 

Age: 20 - 50

Sex: M > F

 

Types

 

A.  Diffuse

- throughout joint synovium

- more difficult to treat / excise fully

 

 PVNS Knee ArthroscopyPVNS Localised

 

B.  Localised

- just one area of synovium

- i.e. suprapatella / medial or lateral gutter

 

PVNS Knee MRI LocalisedPVNS LocalisedPVNS Knee LocalisedPVNS Localised

 

Site

 

Major joints

- knee, hip, shoulder, and ankle

- has been observed in all joints

 

Usually mono-articular

- occasionally multiple joints

 

In aggressive cases, PVS may involve adjacent bone

 

Pathogenesis

 

The cause is unknown

 

Theories

 

1.  Recurrent hemarthrosis 

- cavity of the involved joint is recurringly filled with old unclotted blood

- hemosiderin is a prominent gross and histological finding

- may lead to

 

2.  Inflammatory process 

- marked synovitis

- no virus, bacteria or other inflammatory stimulant has been demonstrated

 

3.  ? Neoplasm

- there are scattered reports of distant metastases to the lungs and other organs leading to death

 

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

- results in severe degenerative arthritis

 

Extensive soft-tissue extension occurs

- may produce peripheral neuropathy by neurovascular bundle involvement

 

In aggressive cases, PVNS may involve adjacent bone

- pathologic fracture secondary to subchondral bone invasion is occasionally seen

- especially in the femoral neck

 

Clinical

 

Intermittent joint effusion 

Modest discomfort

Antecedent trauma 

- often recounted but difficult to relate to the development of PVNS

 

Aspirate

 

Blood tinged / xanthochromic

- in absence of trauma

- highly suspicious of PVNS

 

X-ray

 

Soft tissue swelling 

 

Arthritic changes

 

Bone destruction

- invasion of adjacent metaphyseal cancellous bone

- may be suggestive of neoplasm

 

Bone Scan

 

Increased uptake +++

 

MRI

 

Characteristic T2

- heterogenous picture

- high intensity signal from vascular component

- low intensity signal from hemosiderin 

 

Hemosiderin has low signal intensity on TI and T2

 

PVNS Knee MRIPVNS MRI T1

 

Assess involvement of knee areas

- suprapatella

- medial and lateral gutters

- posterior compartments

- femoral notch

 

Nodular

 

PVNS 1PVNS 2PVNS 3PVNS 4PVNS 5

 

Diffuse

 

PVNS Diffuse 1PVNS Diffuse 2PVNS DiffusePVNS Diffuse 4PVNS Diffuse

 

DDx

 

Haemophilia

Lipoma arborescens

Synovial chondromatosis

 

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

 

Options

 

Open

- posterior recess difficult to access

- or if extracapsular

 

PVNS Posterior KneePVNS Posterior Knee

 

Arthroscopic

- often need posterior cannulas / portals

- takes up to 2 hours

 

PVNS ACL ArthroscopyACL post PVNS Debridement

 

PVNS debridement kneePVNS Knee

 

Results

 

Kim et al Clin Orthop Research 2000

- 11 patients with localised PVNS of the knee treated arthroscopically

- no recurrences at 2 - 4 years

 

Chin et al JBJS Am 2002

- treatment of recurrent PVNS in 40 patients

- repeat surgery with post op radiation synovectomy or DXRT if residual disease

- best outcomes with complete surgical excision of all disease