Synovial Proliferations

Lipoma Arborescens

 

Lipoma Arborescens Knee ArthroscopyLipoma Arborescens Knee Arthroscopy 1Lipoma Arborescens Knee Arthroscopy 2

 

Definition

 

Proliferative synovial condition

- characterised by synovial villi

- centre is lipoma

 

Clinical

 

Lipoma Arborescens

 

Most common in the knee

- massive synovial swelling

- large effusion

 

Problems

 

Can lead to early degenerative change

 

Aetiology

 

Unknown

- postulated to be related to minor knee trauma

 

Diagnosis

 

MRI

- synovial proliferation

- signal similar to surrounding fat

 

Lipoma Arborescens MRI AxialLipoma Arborescens MRI SagittalLipoma Arborescens OCD

 

Arthroscopy

- yellow brown polypoid / frond like villous synovitis

 

DDX

 

PVNS

Synovial Chondromatosis

 

Management

 

Options

 

1.  Arthroscopic Debridement

 

2.  Open Debridement

 

3.  Radionuclide Injection

- Yttrium 90

- not proven to work

- risk skin necrosis

 

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

 

Synovial Chondromatosis

DefinitionSynovial Chondromatosis Knee MRI

 

Chondroid Metaplasia of synovium affecting large joints

 

Nodules of hyaline cartilage

- formed in the subsynovial layer of joint capsules

 

Epidemiology

 

Rare lesion

Most common in 20's and 30's

Sex: M > F (2:1)

Monoarticular

 

Site

 

Any synovial lined joint, tendon or bursal cavity 

 

Marked predilection for large joints 

 

Knee (70%) > Hip > Elbow > Shoulder

 

Subtypes

 

Primary

 

Secondary

- more common

- preexisting OA/RA/AVN/Charcot/TB

 

Pathology

 

Primary

 

Mesenchymal cells in joint capsule (subsynovial layer) become Chondroblasts instead of Fibroblasts

- form nests of cartilage

- nests grow & protrude into joint

- covered by synovium

- eventually become pedunculated into joint

- connected by synovial stalk

 

Then break off & lie free in joint as cartilaginous LB

- Continue to grow in joint 2° synovial diffusion

- can undergo secondary calcification and ossify

 

Secondary

 

Patient with shearing chondral injury

- cartilage cells can seed synovium and continue to grow

 

Patella Chondral DamageSecondary ChondromatosisSecondary Synovial Chondromatosis

 

Histology

 

Central necrotic area that may be calcified

- peripheral ring of viable chondrocytes 

- disorganized chondrocytes with cellular atypia

- can be difficult to pick from chondrosarcoma

 

Stages

Milgram 1977 JBJS

 

Phase 1 - Early; Synovitis, no loose bodies

Phase 2 - Transitional ; Synovitis & loose bodies

Phase 3-  Late ; Loose bodies, no synovitis

 

Clinical

 

Pain & swelling

Loss of ROM

Locking & giving way

Multiple loose bodies

 

X-ray

 

Calcified lesions

 

Loose bodies in suprapatellar pouch

 

MRI

 

Synovial Proliferation

 

Subsynovial masses

- same signal intensity as cartilage

 

Synovial Chondromatosis MRI KneeMRI Knee Synovial Chondromatosis

 

Arthroscopy

 

Synovial proliferation

- localised or generalised

- can see cartilage growing from synovium

 

Multiple loose bodies +++

 

Knee ChondromatosisKnee Chondromatosis

 

Knee ChondromatosisKnee Chondromatosis

 

 

Management

 

Timing

 

Early surgery to prevent secondary degeneration

 

Biopsy

 

Hip

 

Options

 

1. Arthroscopic

 

2.  Open without dislocation

- leave synovium on ligamentum teres

 

3.  Open with dislocation

- lower recurrence

- risk AVN

- Ganz anterior open dislocation

 

Results

 

Boyer et al JBJS Br 2008

- arthroscopic debridement in 111 patients, follow up average 6 years

- 20% required subsequent repeat arthroscopy

- 38% required subsequent open synovectomy

- 20% went on to require THR

 

De Sa et al Arthroscopy 2014

- systematic review of arthroscopic hip debridement

- 7.1% recurrence rate

- minor complication rate 1%

 

 

Lim et al JBJS Am 2006

 

- 21 cases treated with open synovectomy

- 8 treated with arthrotomy alone with 2 recurrences

- 13 treated with surgical dislocation with no recurrences

- recommend dislocation with extensive disease

 

Knee

 

Results

 

Ogilvie-Harris et al Arthroscopy 1994

- 13 patients with generalised disease

- 5 treated with removal loose bodies only

- 8 with synovectomy

- lower recurrence in synovectomy group

 

Shoulder

 

Results

 

Lunn et al JBJS Br 2007

- 15 patients, half primary and half secondary

- arthritic changes present in 8 prior to treatment, 11 after

- arthroscopic synovecotmy + open biceps tenotomy if this area involved

- good pain relief but no improvement in ROM